Reproductive success and habitat characteristics of Golden-winged Warblers in high-elevation pasturelands

USGS Publications Warehouse

Wood, Petra; Aldinger, Kyle R.

2016-01-01

The Golden-winged Warbler (Vermivora chrysoptera) is one of the most rapidly declining vertebrate species in the Appalachian Mountains. It is the subject of extensive range-wide research and conservation action. However, little is known about this species' breeding ecology in high-elevation pasturelands, a breeding habitat with conservation potential considering the U.S. Natural Resource Conservation Service's Working Lands for Wildlife program targeting private lands in the Appalachian Mountains. We located 100 nests of Golden-winged Warblers in pastures in and around the Monongahela National Forest in West Virginia during 2008–2012. Daily nest survival rate (mean ± SE  =  0.962 ± 0.006), clutch size (4.5 ± 0.1), and number of young fledged per nest attempt (2.0 ± 0.2) and successful nest (4.0 ± 0.1) fell within the range of values reported in other parts of the species' range and were not significantly affected by year or the presence/absence of cattle grazing. Classification tree analysis revealed that nests were in denser vegetation (≥52%) and closer to forest edges (<36.0 m) and shrubs (<7.0 cm) than random locations within the male's territory. Successful nests had significantly more woody cover (≥9%) within 1 m than failed nests. Our results suggest that cattle grazing at 1.2–2.4 ha of forage/animal unit with periodic mowing can create and maintain these characteristics without interfering with the nesting of Golden-winged Warblers. High-elevation pasturelands may provide a refuge for remaining populations of Golden-winged Warblers in this region.

Tropical flatback turtle (Natator depressus) embryos are resilient to the heat of climate change.

PubMed

Howard, Robert; Bell, Ian; Pike, David A

2015-10-01

Climate change is threatening reproduction of many ectotherms by increasing nest temperatures, potentially making it more difficult for females to locate nest sites that provide suitable incubation regimes during embryonic development. Elevated nest temperatures could increase the incidence of embryonic mortality and/or maladaptive phenotypes. We investigated whether elevated nest temperatures reduce hatching success in tropical flatback turtles (Natator depressus) nesting in the Gulf of Carpentaria, Australia. Egg incubation treatments began at 29.5°C and progressively increased in temperature throughout incubation, up to maxima of 31, 32, 33, 34 and 35°C. Elevated nest temperatures did not reduce hatching success or hatchling body size relative to control temperatures (29.5°C), but did speed up embryonic development. A combination of sudden exposure to high temperatures during the first 2 weeks of incubation (>36°C for 48 h) and prolonged warming throughout incubation (from 29.5-35°C) did not reduce hatching success. We also recorded an unusually high pivotal sex-determining temperature in this flatback turtle population relative to other sea turtle populations: an equal ratio of male and female hatchlings is produced at ∼30.4°C. This adaptation may allow some flatback turtle populations to continue producing large numbers of hatchlings of both sexes under the most extreme climate change scenarios. Some tropical populations of nesting flatbacks may possess important adaptations to high-temperature incubation environments, which are not found in more southerly temperate populations. © 2015. Published by The Company of Biologists Ltd.

Host–parasite behavioral interactions in a recently introduced, whooping crane population

USGS Publications Warehouse

King, Richard S.; McKann, Patrick C.; Gray, Brian R.; Putnam, Michael S.

2015-01-01

The whooping crane Grus americana has a long conservation history, but despite multiple attempts across North America, introduction success is lacking. Recently introduced, captively reared whooping cranes have had periods of poor reproductive performance in central Wisconsin that sometimes coincided with black fly (Diptera: Simuliidae) emergences. Sandhill crane Grus canadensis reproductive performance in central Wisconsin is approximately double that of whooping cranes. We used comfort behaviors as a measure of black fly harassment to infer whether behavioral differences existed between nesting sandhill cranes and nesting whooping cranes and between successful and unsuccessful whooping crane pairs. To further explore the interaction between black flies and incubating whooping cranes, we examined differences in behaviors between incubating birds and their off-nest mates. Compared to their off-nest mates, incubating whooping cranes exhibited elevated comfort behaviors, suggesting a bird at a nest may experience greater harassment from black flies. Sandhill cranes had elevated head-flicks over whooping cranes. Whooping cranes exhibited more head-rubs than sandhill cranes, and successful whooping crane pairs had elevated head-rubs over pairs that deserted their nests. Behavioral differences between sandhill cranes and whooping cranes as well as differences in reproductive performance, could be explained by exposure to local breeding conditions. Whereas sandhill cranes have nested in the area for hundreds, if not thousands, of years, whooping cranes were only recently introduced to the area. Behavioral differences between the species as well as those between successful and unsuccessful whooping crane pairs could also be explained by the effect of captive exposure, which could affect all whooping crane introductions.

Mediation of a corticosterone-induced reproductive conflict.

PubMed

Love, Oliver P; Breuner, Creagh W; Vézina, François; Williams, Tony D

2004-06-01

Current research in birds suggests that a conflict should exist during reproduction for the role of the glucocorticoid corticosterone (CORT). While elevated levels have been correlated with the increased energetic demand of raising offspring, elevated CORT levels have traditionally been implicated in reproductive abandonment. We examined the relationship between CORT and nest desertion in breeding wild female European starlings (Sturnus vulgaris) incorporating analyses of both total circulating levels and 'free', unbound CORT through analysis of corticosteroid-binding globulin (CBG). Free baseline CORT levels of nest-abandoning birds were significantly higher than nonabandoning birds within each stage, with chick-rearing birds exhibiting the highest free baseline CORT levels, while concurrently remaining the most resistant stage to nest desertion. Elevated free baseline CORT levels in chick-rearing birds were not due to increased total CORT secretion, but rather to a decrease in CBG levels. Overall, our results suggest that CORT and CBG interact to play a role in mediating the increased energetic demand of offspring, while minimizing the chances of nest desertion, thereby alleviating any potential behavioral conflict for CORT during reproduction. Furthermore, these results demonstrate that the traditional view of the role of CORT during reproduction is much more complex than previously appreciated. Together with mounting evidence, we suggest that elevated corticosteroid levels are an inherent and necessary part of reproduction in nonmammalian tetrapods.

Risk of predation and weather events affect nest site selection by sympatric Pacific (Gavia pacifica) and Yellow-billed (Gavia adamsii) loons in Arctic habitats

USGS Publications Warehouse

Haynes, Trevor B.; Schmutz, Joel A.; Lindberg, Mark S.; Rosenberger, Amanda E.

2014-01-01

Pacific (Gavia pacifica) and Yellow-billed (G. adamsii) loons nest sympatrically in Arctic regions. These related species likely face similar constraints and requirements for nesting success; therefore, use of similar habitats and direct competition for nesting habitat is likely. Both of these loon species must select a breeding lake that provides suitable habitat for nesting and raising chicks; however, characteristics of nest site selection by either species on interior Arctic lakes remains poorly understood. Here, logistic regression was used to compare structural and habitat characteristics of all loon nest locations with random points from lakes on the interior Arctic Coastal Plain, Alaska. Results suggest that both loon species select nest sites to avoid predation and exposure to waves and shifting ice. Loon nest sites were more likely to be on islands and peninsulas (odds ratio = 16.13, 95% CI = 4.64–56.16) than mainland shoreline, which may help loons avoid terrestrial predators. Further, nest sites had a higher degree of visibility (mean degrees of visibility to 100 and 200 m) of approaching predators than random points (odds ratio = 2.57, 95% CI = 1.22–5.39). Nests were sheltered from exposure, having lower odds of being exposed to prevailing winds (odds ratio = 0.34, 95% CI = 0.13–0.92) and lower odds of having high fetch values (odds ratio = 0.46, 95% CI = 0.22–0.96). Differences between Pacific and Yellow-billed loon nesting sites were subtle, suggesting that both species have similar general nest site requirements. However, Yellow-billed Loons nested at slightly higher elevations and were more likely to nest on peninsulas than Pacific Loons. Pacific Loons constructed built up nests from mud and vegetation, potentially in response to limited access to suitable shoreline due to other territorial loons. Results suggest that land managers wishing to protect habitats for these species should focus on lakes with islands as well as shorelines sheltered from exposure to prevailing wind and ice patterns.

Loggerhead sea turtle environmental sex determination: implications of moisture and temperature for climate change based predictions for species survival.

PubMed

Wyneken, Jeanette; Lolavar, Alexandra

2015-05-01

It has been proposed that because marine turtles have environmentally determined sex by incubation temperature, elevated temperatures might skew sex ratios to unsustainable levels, leading to extinction. Elevated temperatures may also reduce availability of suitable nesting sites via sea level rise. Increased tropical storm activity can directly affect nest site moisture, embryonic development, and the probability that nests will survive. Here, we question some of these assumptions and review the limits of sex ratio estimates. Sea turtles may be more resilient to climate change than previously thought, in part because of hitherto unappreciated mechanisms for coping with variable incubation conditions. © 2015 Wiley Periodicals, Inc.

Mixed Species Flock, Nest Height, and Elevation Partially Explain Avian Haemoparasite Prevalence in Colombia

PubMed Central

González, Angie D.; Matta, Nubia E.; Ellis, Vincenzo A.; Miller, Eliot T.; Ricklefs, Robert E.; Gutiérrez, H. Rafael

2014-01-01

The high avian biodiversity present in the Neotropical region offers a great opportunity to explore the ecology of host-parasite relationships. We present a survey of avian haemoparasites in a megadiverse country and explore how parasite prevalences are related to physical and ecological host characteristics. Using light microscopy, we documented the presence of haemoparasites in over 2000 individuals belonging to 246 species of wild birds, from nine localities and several ecosystems of Colombia. We analysed the prevalence of six avian haemoparasite taxa in relation to elevation and the following host traits: nest height, nest type, foraging strata, primary diet, sociality, migratory behaviour, and participation in mixed species flocks. Our analyses indicate significant associations between both mixed species flocks and nest height and Haemoproteus and Leucocytozoon prevalence. The prevalence of Leucocytozoon increased with elevation, whereas the prevalence of Trypanosoma and microfilariae decreased. Plasmodium and Haemoproteus prevalence did not vary significantly with elevation; in fact, both parasites were found up to 3300m above sea level. The distribution of parasite prevalence across the phylogeny of bird species included in this study showed little host phylogenetic signal indicating that infection rates in this system are evolutionarily labile. Vector distribution as well as the biology of transmission and the maintenance of populations of avian haemoparasites deserve more detailed study in this system. PMID:24950223

Mixed species flock, nest height, and elevation partially explain avian haemoparasite prevalence in Colombia.

PubMed

González, Angie D; Matta, Nubia E; Ellis, Vincenzo A; Miller, Eliot T; Ricklefs, Robert E; Gutiérrez, H Rafael

2014-01-01

The high avian biodiversity present in the Neotropical region offers a great opportunity to explore the ecology of host-parasite relationships. We present a survey of avian haemoparasites in a megadiverse country and explore how parasite prevalences are related to physical and ecological host characteristics. Using light microscopy, we documented the presence of haemoparasites in over 2000 individuals belonging to 246 species of wild birds, from nine localities and several ecosystems of Colombia. We analysed the prevalence of six avian haemoparasite taxa in relation to elevation and the following host traits: nest height, nest type, foraging strata, primary diet, sociality, migratory behaviour, and participation in mixed species flocks. Our analyses indicate significant associations between both mixed species flocks and nest height and Haemoproteus and Leucocytozoon prevalence. The prevalence of Leucocytozoon increased with elevation, whereas the prevalence of Trypanosoma and microfilariae decreased. Plasmodium and Haemoproteus prevalence did not vary significantly with elevation; in fact, both parasites were found up to 3300 m above sea level. The distribution of parasite prevalence across the phylogeny of bird species included in this study showed little host phylogenetic signal indicating that infection rates in this system are evolutionarily labile. Vector distribution as well as the biology of transmission and the maintenance of populations of avian haemoparasites deserve more detailed study in this system.

Beach Geomorphology and Kemp's Ridley (Lepidochelys kempii) Nest Site Selection along Padre Island, Texas, USA

NASA Astrophysics Data System (ADS)

Culver, M.; Gibeaut, J. C.; Shaver, D. J.; Tissot, P.; Starek, M. J.

2017-12-01

The Kemp's ridley sea turtle (Lepidochelys kempii) is the most endangered sea turtle in the world, largely due to the limited geographic range of its nesting habitat. In the U.S., the majority of nesting occurs along Padre Island National Seashore (PAIS) in Texas. There has been limited research regarding the connection between beach geomorphology and Kemp's ridley nesting patterns, but studies concerning other sea turtle species suggest that certain beach geomorphology variables, such as beach slope and width, influence nest site selection. This research investigates terrestrial habitat variability of the Kemp's ridley sea turtle and quantifies the connection between beach geomorphology and Kemp's ridley nest site selection on PAIS and South Padre Island, Texas. Airborne topographic lidar data collected annually along the Texas coast from 2009 through 2012 was utilized to extract beach geomorphology characteristics, such as beach slope and width, dune height, and surface roughness, among others. The coordinates of observed Kemp's ridley nests from corresponding years were integrated with the aforementioned data in statistical models, which analyzed the influence of both general trends in geomorphology and individual morphologic variables on nest site selection. This research identified the terrestrial habitat variability of the Kemp's ridley and quantified the range of geomorphic characteristics of nesting beaches. Initial results indicate that dune width, beach width, and wind speed are significant variables in relation to nest presence, using an alpha of 0.1. Higher wind speeds and narrower beaches and foredunes favor nest presence. The average nest elevation is 1.13 m above mean sea level, which corresponds to the area directly below the potential vegetation line, and the majority of nesting occurs between the elevations of 0.68 m and 1.4 m above mean sea level. The results of this study include new information regarding Kemp's ridley beach habitat and its influence on nesting patterns that could be useful for the conservation and management of the species.

Discovery of a new Kittlitz's murrelet nest: Clues to habitat selection and nest-site fidelity

USGS Publications Warehouse

Piatt, John F.; Naslund, Nancy L.; van Pelt, Thomas I.

1999-01-01

On 13 June 1993, a new Kittlitz's murrelet (Brachyramphus brevirostris) nest was discovered near Red Mountain on the Kenai Peninsula, Alaska. The nest was on a 22° slope at about 900 m elevation with a northeast aspect, and contained a 60.2 × 40.6 mm egg that weighed 49.0 g. Downy feathers and weathered fecal material found at the nest indicated re-use from a previous year, suggesting possible nest site fidelity. The nest was located in an area scoured by winds and free of snow during early spring, suggesting that this may be an important mesoscale factor influencing selection of nesting habitat. Proximity to suitable foraging habitat, particularly sheltered bays and glacial river outflows, may affect breeding habitat choice over larger spatial scales.

Post-Wildfire Potential for Carbon and Nitrogen Sequestration in the Southwestern United States in Restored Ephemeral and Intermittent Stream Channels

NASA Astrophysics Data System (ADS)

Callegary, J. B.; Norman, L.; Eastoe, C. J.; Sankey, J. B.; Youberg, A.

2016-12-01

The Kemp's ridley sea turtle (Lepidochelys kempii) is the most endangered sea turtle in the world, largely due to the limited geographic range of its nesting habitat. In the U.S., the majority of nesting occurs along Padre Island National Seashore (PAIS) in Texas. There has been limited research regarding the connection between beach geomorphology and Kemp's ridley nesting patterns, but studies concerning other sea turtle species suggest that certain beach geomorphology variables, such as beach slope and width, influence nest site selection. This research investigates terrestrial habitat variability of the Kemp's ridley sea turtle and quantifies the connection between beach geomorphology and Kemp's ridley nest site selection on PAIS and South Padre Island, Texas. Airborne topographic lidar data collected annually along the Texas coast from 2009 through 2012 was utilized to extract beach geomorphology characteristics, such as beach slope and width, dune height, and surface roughness, among others. The coordinates of observed Kemp's ridley nests from corresponding years were integrated with the aforementioned data in statistical models, which analyzed the influence of both general trends in geomorphology and individual morphologic variables on nest site selection. This research identified the terrestrial habitat variability of the Kemp's ridley and quantified the range of geomorphic characteristics of nesting beaches. Initial results indicate that dune width, beach width, and wind speed are significant variables in relation to nest presence, using an alpha of 0.1. Higher wind speeds and narrower beaches and foredunes favor nest presence. The average nest elevation is 1.13 m above mean sea level, which corresponds to the area directly below the potential vegetation line, and the majority of nesting occurs between the elevations of 0.68 m and 1.4 m above mean sea level. The results of this study include new information regarding Kemp's ridley beach habitat and its influence on nesting patterns that could be useful for the conservation and management of the species.

The importance of microclimate variation in determining size, growth and survival of avian offspring: experimental evidence from a cavity nesting passerine.

PubMed

Dawson, Russell D; Lawrie, Cheyenne C; O'Brien, Erin L

2005-07-01

Organisms are expected to balance energy allocation in such a way that fitness is maximized. While much research has focussed on allocation strategies of reproducing parents, in particular birds, relatively little attention has been paid to how nestlings allocate energy while in the nest. Nestling birds are faced with a trade-off between devoting energy to growth or to thermoregulation, and in altricial species it is likely that the thermal environment of the nest site influences the nature of this trade-off. Here, we experimentally investigate how altering the microclimate of nests affects the growth, size and survival, as well as cell-mediated immune (CMI) response, of nestling tree swallows (Tachycineta bicolor) in a temperate environment. We place air-activated heating pads in nests of swallows when young were between 4 days and 16 days of age, and compared performance of offspring to control nests. Our manipulation raised temperatures of heated nests by approximately 5 degrees C compared to control nests. Offspring in heated nests had enhanced survival while in the nest, and we also found that they were heavier and had longer ninth primary feathers at 16 days of age. In addition, heating nest boxes resulted in significantly faster growth of primaries, and there was a trend for growth rates of mass to also be higher in heated nests. There were no significant differences between heated and control nests in growth rate or size of tarsus at age 16 days, and we speculate that this lack of response to elevated nest temperatures may be due to growth of skeletal structures being limited by other factors such as calcium availability. We also found no difference between heated and control nests in CMI response. Nonetheless, our results show overall that increasing temperatures of nests has significant benefits that enhance the fitness of offspring. As provisioning rates to offspring did not differ between heated and control nests, we suspect that the beneficial effects of heating were not the consequence of changes in parental behaviour. Our results provide insight into factors, other than food supply, that have important consequences in determining reproductive success of birds breeding in temperate environments.

Effects of climate and exurban development on nest predation and predator presence in the southern Appalachian Mountains (USA).

PubMed

Lumpkin, Heather A; Pearson, Scott M; Turner, Monica G

2012-08-01

In the eastern United States, land-use and climate change have likely contributed to declines in the abundance of Neotropical migrant birds that occupy forest interiors, but the mechanisms are not well understood. We conducted a nest-predation experiment in southern Appalachian Mountain forests (North Carolina, U.S.A.) during the 2009 and 2010 breeding seasons to determine the effects of exurban development and temperature on predator presence and the average number of days until eggs in an artificial nest were disturbed by predators. We baited artificial nests with quail (Excalfactoria chinensi) eggs and monitored them for 18 days. We used clay eggs, track plates, and motion-triggered cameras to detect and identify nest predators. The average number of days a nest was undisturbed decreased as mean temperature increased and, to a lesser extent, as the density of buildings increased. Nests on the ground were more often depredated than those in trees, likely due to increased predation by opossum (Didelphis virginiana) and other carnivores. Raccoons (Procyon lotor), opossums, corvids (Corvus brachyrhynchos and Cyanocitta cristata), chipmunks (Tamias striatus), black bears (Ursus americanus), and domestic cats (Felis catus) were the most commonly detected predators. Presence of these predators did not vary as a function of mean temperature. Domestic cats and corvids were detected more frequently in plots with high rather than low densities of buildings. Forest-interior specialists and Neotropical migrants often nest in cool, high-elevation areas with low housing density. These bird species, especially those that nest on the ground, may be most vulnerable to increased nest predation if temperature and exurban development increase at higher elevations as anticipated. ©2012 Society for Conservation Biology.

Differential behavioural and endocrine responses of common voles (Microtus arvalis) to nest predators and resource competitors.

PubMed

Liesenjohann, Monique; Liesenjohann, Thilo; Palme, Rupert; Eccard, Jana Anja

2013-09-08

Adaptive behavioural strategies promoting co-occurrence of competing species are known to result from a sympatric evolutionary past. Strategies should be different for indirect resource competition (exploitation, e.g., foraging and avoidance behaviour) than for direct interspecific interference (e.g., aggression, vigilance, and nest guarding). We studied the effects of resource competition and nest predation in sympatric small mammal species using semi-fossorial voles and shrews, which prey on vole offspring during their sensitive nestling phase. Experiments were conducted in caged outdoor enclosures. Focus common vole mothers (Microtus arvalis) were either caged with a greater white-toothed shrew (Crocidura russula) as a potential nest predator, with an herbivorous field vole (Microtus agrestis) as a heterospecific resource competitor, or with a conspecific resource competitor. We studied behavioural adaptations of vole mothers during pregnancy, parturition, and early lactation, specifically modifications of the burrow architecture and activity at burrow entrances. Further, we measured pre- and postpartum faecal corticosterone metabolites (FCMs) of mothers to test for elevated stress hormone levels. Only in the presence of the nest predator were prepartum FCMs elevated, but we found no loss of vole nestlings and no differences in nestling body weight in the presence of the nest predator or the heterospecific resource competitor. Although the presence of both the shrew and the field vole induced prepartum modifications to the burrow architecture, only nest predators caused an increase in vigilance time at burrow entrances during the sensitive nestling phase. Voles displayed an adequate behavioural response for both resource competitors and nest predators. They modified burrow architecture to improve nest guarding and increased their vigilance at burrow entrances to enhance offspring survival chances. Our study revealed differential behavioural adaptations to resource competitors and nest predators.

Differential behavioural and endocrine responses of common voles (Microtus arvalis) to nest predators and resource competitors

PubMed Central

2013-01-01

Background Adaptive behavioural strategies promoting co-occurrence of competing species are known to result from a sympatric evolutionary past. Strategies should be different for indirect resource competition (exploitation, e.g., foraging and avoidance behaviour) than for direct interspecific interference (e.g., aggression, vigilance, and nest guarding). We studied the effects of resource competition and nest predation in sympatric small mammal species using semi-fossorial voles and shrews, which prey on vole offspring during their sensitive nestling phase. Experiments were conducted in caged outdoor enclosures. Focus common vole mothers (Microtus arvalis) were either caged with a greater white-toothed shrew (Crocidura russula) as a potential nest predator, with an herbivorous field vole (Microtus agrestis) as a heterospecific resource competitor, or with a conspecific resource competitor. Results We studied behavioural adaptations of vole mothers during pregnancy, parturition, and early lactation, specifically modifications of the burrow architecture and activity at burrow entrances. Further, we measured pre- and postpartum faecal corticosterone metabolites (FCMs) of mothers to test for elevated stress hormone levels. Only in the presence of the nest predator were prepartum FCMs elevated, but we found no loss of vole nestlings and no differences in nestling body weight in the presence of the nest predator or the heterospecific resource competitor. Although the presence of both the shrew and the field vole induced prepartum modifications to the burrow architecture, only nest predators caused an increase in vigilance time at burrow entrances during the sensitive nestling phase. Conclusion Voles displayed an adequate behavioural response for both resource competitors and nest predators. They modified burrow architecture to improve nest guarding and increased their vigilance at burrow entrances to enhance offspring survival chances. Our study revealed differential behavioural adaptations to resource competitors and nest predators. PMID:24010574

Use of radio-telemetry to reduce bias in nest searching

USGS Publications Warehouse

Powell, L.A.; Lang, J.D.; Krementz, D.G.; Conroy, M.J.

2005-01-01

We used traditional searching, as well as radio-telemetry, to find 125 Wood Thrush (Hylocichla mustelina) nests during 1994?1996 at the Piedmont National Wildlife Refuge in Georgia, USA. We compared daily nest survival rates for 66 nests of radio-marked birds with 59 nests of birds found through systematic searching. By using radio-telemetry, we found Wood Thrush nests in higher elevation pine habitats, in addition to the more usual hardwood forests with moist soils. We found nests of radio-marked birds farther from streams than nests found by systematic searching. Thirty-two percent of radio-marked birds' nests were found at the tops of slopes, compared to 15% of the nests found by traditional searching. In addition, radio-marked birds generally moved up-slope for re-nesting attempts. Although the distribution of nests found with telemetry and searching varied, daily nest survival did not vary between the two groups. Radio-telemetry provided new information about Wood Thrush nesting habitats. We believe radio-telemetry can be a valuable addition to traditional searching techniques; it has the potential to provide a sample of nests free from a priori habitat biases.

Nest movement by piping plovers in response to changing habitat conditions

USGS Publications Warehouse

Wiltermuth, Mark T.; Anteau, Michael J.; Sherfy, Mark H.; Shaffer, Terry L.

2009-01-01

Birds that nest along reservoir or river shorelines may face fluctuating water levels that threaten nest survival. On Lake Sakakawea of the upper Missouri River, 37 and 70% of Piping Plover (Charadrius melodus) nests found in 2007 and 2008, respectively, were initiated at elevations inundated prior to projected hatch date. We describe eight events at seven nests in which adult Piping Plovers appeared to have moved active nests threatened by rising water or gathered eggs apparently displaced by rising water on Lake Sakakawea and the Garrison reach of the upper Missouri River. Additionally, we describe one nest that was moved after the habitat at the nest site had been disturbed by domestic cattle. Our observations and evidence indicate that adult Piping Plovers are capable of moving eggs and establishing nests at new sites during incubation. Furthermore, our results suggest that Piping Plovers evaluate their reproductive investment under potential threat of nest loss and may be capable of acting prospectively (moving nests prior to inundation) and reactively (regathering eggs after inundation) to avoid nest failure.

Inter-assemblage facilitation: the functional diversity of cavity-producing beetles drives the size diversity of cavity-nesting bees.

PubMed

Sydenham, Markus A K; Häusler, Lise D; Moe, Stein R; Eldegard, Katrine

2016-01-01

Inter-specific interactions are important drivers and maintainers of biodiversity. Compared to trophic and competitive interactions, the role of non-trophic facilitation among species has received less attention. Cavity-nesting bees nest in old beetle borings in dead wood, with restricted diameters corresponding to the body size of the bee species. The aim of this study was to test the hypothesis that the functional diversity of cavity-producing wood boring beetles - in terms of cavity diameters - drives the size diversity of cavity-nesting bees. The invertebrate communities were sampled in 30 sites, located in forested landscapes along an elevational gradient. We regressed the species richness and abundance of cavity nesting bees against the species richness and abundance of wood boring beetles, non-wood boring beetles and elevation. The proportion of cavity nesting bees in bee species assemblage was regressed against the species richness and abundance of wood boring beetles. We also tested the relationships between the size diversity of cavity nesting bees and wood boring beetles. The species richness and abundance of cavity nesting bees increased with the species richness and abundance of wood boring beetles. No such relationship was found for non-wood boring beetles. The abundance of wood boring beetles was also related to an increased proportion of cavity nesting bee individuals. Moreover, the size diversity of cavity-nesting bees increased with the functional diversity of wood boring beetles. Specifically, the mean and dispersion of bee body sizes increased with the functional dispersion of large wood boring beetles. The positive relationships between cavity producing bees and cavity nesting bees suggest that non-trophic facilitative interactions between species assemblages play important roles in organizing bee species assemblages. Considering a community-wide approach may therefore be required if we are to successfully understand and conserve wild bee species assemblages in forested landscapes.

Stabilities of ant nests and their adjacent soils

NASA Astrophysics Data System (ADS)

Echezona, B. C.; Igwe, C. A.

2012-10-01

Nests habour ants and termites and protect them from harsh environmental conditions. The structural stabilities of nests were studied to ascertain their relative vulnerability to environmental stresses. Arboreal-ant nests were pried from different trees, while epigeous-termite nests were excavated from soil surface within the sample area. Soils without any visible sign of ant or termite activity were also sampled 6 m away from the nests as control. Laboratory analysis result showed that irrespective of the tree hosts, the aggregate stabilities of the ant nests were lower than those of the ground termite, with nests formed on Cola nitida significantly showing lower aggregate stability (19.7%) than other antnest structures. Clay dispersion ratio, moisture content, water stable aggregate class <0.25mm and sand mass were each negatively correlated with aggregate stability, while water stable aggregate class1.00-0.50 mm gave a positive correlation. Nest structures were dominated more by water stable aggregate class >2.00 mm but path analysis demonstrated that water stable aggregate class <0.25 mm contributed most to the higher aggregate stability of the termite nest than the other nest. Nest aggregates had greater structural stability compared to the control soil. The higher structural stability of termite nests over other nest and soil was considered a better adaptive mechanism against body desiccation.

Caterpillars benefit from thermal ecosystem engineering by wandering albatrosses on sub-Antarctic Marion Island.

PubMed

Sinclair, Brent J; Chown, Steven L

2006-03-22

Wandering albatrosses (Diomedea exulans) nest on Southern Ocean islands, building elevated nests upon which they incubate eggs and raise chicks, and which the chicks occupy through winter. The nests support high invertebrate biomass, including larvae of the flightless moth Pringleophaga marioni. Here we argue that high biomass of P. marioni in the nests is not associated with nutrient loading as previously suspected, but that higher temperatures in the nests increase growth and feeding rate, and decrease deleterious repeated cold exposure, providing fitness advantages for P. marioni. Thus, wandering albatrosses may be serving as thermal engineers, modifying temperature and therefore enabling better resource use by P. marioni.

Construction patterns of birds' nests provide insight into nest-building behaviours.

PubMed

Biddle, Lucia; Goodman, Adrian M; Deeming, D Charles

2017-01-01

Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch ( Pyrrhula pyrrhula ) nests as a model for open-nesting songbird species that construct a "twig" nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process.

Nest-site characteristics of Glyptemys muhlenbergii (Bog Turtle) in New Jersey and Pennsylvania

USGS Publications Warehouse

Zappalorti, Robert T.; Lovich, Jeffrey E.; Farrell, Ray F.; Torocco, Michael E.

2015-01-01

Nest-site selection can affect both the survival and fitness of female turtles and their offspring. In many turtle species, the nest environment determines the thermal regime during incubation, length of incubation period, sex ratio of the hatchlings, and exposure to predators and other forms of mortality for both mothers and their offspring. Between 1974 and 2012, we collected detailed data on habitat variables at 66 Glyptemys muhlenbergii (Bog Turtle) nests in 9 different bogs, fens, and wetland complexes in New Jersey and Pennsylvania. The nests had a mean elevation above the substrate of 8.2 cm, and many were shallow and located in raised tussocks of grass or sedges. Females covered most nests, but we also observed partially or completely uncovered eggs. Some females deposited eggs in communal nests; we found 4 nests with 2 separate clutches, and 2 nests with 3 clutches. Principal component analysis confirmed the importance of cover and vegetation to nest-site selection in this species. Availability of open, shade-free, wet nesting areas is an important habitat requirement for Bog Turtles.

An improved spatial contour tree constructed method

NASA Astrophysics Data System (ADS)

Zheng, Yi; Zhang, Ling; Guilbert, Eric; Long, Yi

2018-05-01

Contours are important data to delineate the landform on a map. A contour tree provides an object-oriented description of landforms and can be used to enrich the topological information. The traditional contour tree is used to store topological relationships between contours in a hierarchical structure and allows for the identification of eminences and depressions as sets of nested contours. This research proposes an improved contour tree so-called spatial contour tree that contains not only the topological but also the geometric information. It can be regarded as a terrain skeleton in 3-dimention, and it is established based on the spatial nodes of contours which have the latitude, longitude and elevation information. The spatial contour tree is built by connecting spatial nodes from low to high elevation for a positive landform, and from high to low elevation for a negative landform to form a hierarchical structure. The connection between two spatial nodes can provide the real distance and direction as a Euclidean vector in 3-dimention. In this paper, the construction method is tested in the experiment, and the results are discussed. The proposed hierarchical structure is in 3-demintion and can show the skeleton inside a terrain. The structure, where all nodes have geo-information, can be used to distinguish different landforms and applied for contour generalization with consideration of geographic characteristics.

Waterfowl productivity and use of nesting structures in the prairie pothole region

USGS Publications Warehouse

Johnson, Rex R.; Higgins, Kenneth F.; Ball, I.J.; Kohn, Stan C.

1994-01-01

Over-water duck nests are usually more successful than upland nests. We evaluated mallard (Anas platyrhynchos) and giant Canada goose (Branta canadensis maxima) use of nest baskets, straw and hay bales, and earth-filled culverts and determined nesting success rates by structure type during 1987-1989. Mallards used bales and culverts more than baskets, whereas Canada geese used baskets more than bales or culverts. Nesting success was greatest for baskets and culverts (>80%) and lowest for bales (58.3%). Logistics aside, culverts appear to be the most valuable nesting structures for mallards, and baskets are the most valuable structures for Canada geese.

Optimization of the time series NDVI-rainfall relationship using linear mixed-effects modeling for the anti-desertification area in the Beijing and Tianjin sandstorm source region

NASA Astrophysics Data System (ADS)

Wang, Jin; Sun, Tao; Fu, Anmin; Xu, Hao; Wang, Xinjie

2018-05-01

Degradation in drylands is a critically important global issue that threatens ecosystem and environmental in many ways. Researchers have tried to use remote sensing data and meteorological data to perform residual trend analysis and identify human-induced vegetation changes. However, complex interactions between vegetation and climate, soil units and topography have not yet been considered. Data used in the study included annual accumulated Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m normalized difference vegetation index (NDVI) from 2002 to 2013, accumulated rainfall from September to August, digital elevation model (DEM) and soil units. This paper presents linear mixed-effect (LME) modeling methods for the NDVI-rainfall relationship. We developed linear mixed-effects models that considered the random effects of sample points nested in soil units for nested two-level modeling and single-level modeling of soil units and sample points, respectively. Additionally, three functions, including the exponential function (exp), the power function (power), and the constant plus power function (CPP), were tested to remove heterogeneity, and an additional three correlation structures, including the first-order autoregressive structure [AR(1)], a combination of first-order autoregressive and moving average structures [ARMA(1,1)] and the compound symmetry structure (CS), were used to address the spatiotemporal correlations. It was concluded that the nested two-level model considering both heteroscedasticity with (CPP) and spatiotemporal correlation with [ARMA(1,1)] showed the best performance (AMR = 0.1881, RMSE = 0.2576, adj- R 2 = 0.9593). Variations between soil units and sample points that may have an effect on the NDVI-rainfall relationship should be included in model structures, and linear mixed-effects modeling achieves this in an effective and accurate way.

Creating and managing wetland impoundments to provide habitat for aquatic birds

USGS Publications Warehouse

Perry, M.C.; Kangas, P.; Obrecht, H.H.; Comin, Francisco A.; Herrera-Silveira, Jorge A.; Ramirez-Ramirez, Javier

2000-01-01

Patuxent Research Refuge, located in Central Maryland (USA), has approximately 140 ha of impoundments that were constructed for recreational and wildlife conservation purposes. Impoundments are of three major designs: dammed ravines, excavated basins, and diked ponds. Over 50 species of wetland plants were transplanted to impoundments of Patuxent from many parts of the United States between 1945 and 1963 to determine the species best suited for establishment in tannin-stained infertile waters. The wood duck was the only waterfowl species commonly observed on the Refuge when the area was established, but Canada geese, mallards, and black ducks, were introduced and numerous techniques developed to improve nesting and brood habitat. Twenty-six waterfowl species and 80 species of other water birds have used the impoundments for resting, feeding, or nesting. Management is now conducted to optimize avian biodiversity. Management techniques include drawdowns of water every 3-5 years in most impoundments to provide maximum plant and invertebrate food resources for wildlife. Research on the impounded wetlands at Patuxent has included evaluation of vegetation in regard to water level management, improving nest box design to reduce use of boxes by starlings, imprinting of waterfowl to elevated nesting structures to reduce predation on nests, and drawdown techniques to increase macroinvertebrates. Data on waterfowl abundance are evaluated relative to management activities and a preliminary computer model for management of the impoundments has been developed. Past, present, and future management and research projects are reviewed in this paper.

Importance of structural stability to success of mourning dove nests

USGS Publications Warehouse

Coon, R.A.; Nichols, J.D.; Percival, H.F.

1981-01-01

Studies of nest-site selection and nesting habitats often involve a "characterization" of nests and of habitats in which nests are found. Our objective in the present work is to identify nest-site characteristics that are associated with variation in components of Mourning Dove (Zenaida macroura) fitness (e.g. the probability of a nest succeeding), as opposed to simply "characterizing" dove nest sites. If certain nest- site characteristics affect the probability that a nest will succeed, then we suspect that these characteristics will be associated with either concealment (the probability of detection by certain predators) or structural stability (the probability of eggs or entire nests falling to the ground as a result of wind, rain storms, parental activity, etc.). Although other workers agree that structural stability is an important determinant of Mourning Dove nesting success (e.g. McClure 1944: 384; Woolfenden and Rohwer 1969: 59), we are aware of no actual tests of this hypothesis.

[Structure characteristics of natural nests and its implication to artificial nest frame design for Ciconia boyciana].

PubMed

Wei, Yi-qing; Cui, Guo-fa

2014-12-01

Artificial nest can improve the breeding success of birds in the field, and it has been proved to be more effective to endangered species. We surveyed the structure characteristics of natural nest and the status of the use of artificial nests for oriental white stork, Ciconia boyciana, in Honghe National Nature Reserve, Heilongjiang Province. Differences were investigated among the structure characteristics of the used and unused artificial nests, and natural nests based on one-way ANOVA. It was observed that significant differences in the diameter of nest branch, the vertical an- gle between nest branch, the height of the jointthe height of the nest above ground exited in different nest types. On account of the structure characteristics of the natural nests of C. boyciana, the suitable diameter of nest pillar for artificial nest frame should be 15.0-25.0 cm with the height of 5.0-12.0 m, which would be better if they were constructed by some acid-resistant materials, e.g., cement. The number of nest stands should be 3-4 individuals with the diameter of 9.0-12.0 cm, the vertical angle of 45 degrees-60 degrees, and the length of 90.0-140.0 cm.

Construction patterns of birds’ nests provide insight into nest-building behaviours

PubMed Central

Goodman, Adrian M.

2017-01-01

Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula) nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process. PMID:28265501

Chapter 16: Inland Habitat Associations of Marbled Murrelets in British Columbia

Treesearch

Alan E. Burger

1995-01-01

Most Marbled Murrelets (Brachyramphus marmoratus) in British Columbia nest in the Coastal Western Hemlock biogeoclimatic zone. In this zone, detection frequencies were highest in the moister ecosections and in low elevation forests. Nests and moderately high levels of activity were also found in some forest patches in the subalpine Mountain Hemlock...

Myrmecophagy by Yellowstone grizzly bears

USGS Publications Warehouse

Mattson, D.J.

2001-01-01

I used data collected during a study of radio-marked grizzly bears (Ursus arctos horribilis) in the Yellowstone region from 1977 to 1992 to investigate myrmecophagy by this population. Although generally not an important source of energy for the bears (averaging 8 mm long) nested in logs over small ants (6 mm long) nested under stones. Optimal conditions for consumption of ants occurred on the warmest sites with ample substrate suitable for ant nests. For ants in mounds, this occurred at low elevations at non-forested sites. For ants in logs, this occurred at low elevations or on southerly aspects where there was abundant, large-diameter, well-decomposed woody debris under an open forest canopy. Grizzly bears selected moderately decomposed logs 4a??5 dm in diameter at midpoint. Ants will likely become a more important food for Yellowstone's grizzly bears as currently important foods decline, owing to disease and warming of the regional climate.

The Impact of Ignoring the Level of Nesting Structure in Nonparametric Multilevel Latent Class Models

ERIC Educational Resources Information Center

Park, Jungkyu; Yu, Hsiu-Ting

2016-01-01

The multilevel latent class model (MLCM) is a multilevel extension of a latent class model (LCM) that is used to analyze nested structure data structure. The nonparametric version of an MLCM assumes a discrete latent variable at a higher-level nesting structure to account for the dependency among observations nested within a higher-level unit. In…

Use of a nesting platform by Gull-billed Terns and Black Skimmers at the Salton Sea, California

USGS Publications Warehouse

Molina, Kathy C.; Ricca, Mark A.; Miles, A. Keith; Schoneman, Christian

2009-01-01

In 2006, we constructed an elevated nesting platform at the Salton Sea, California, and monitored its use by Gull-billed Terns and Black Skimmers over three subsequent breeding seasons. Black Skimmers were the first to colonize the platform with a total of five nests in 2006. In 2007 Gull-billed Terns colonized the platform with a total of 28 nests and the number of Black Skimmer nests increased to 20. Neither species nested on the platform in 2008. Low success for both species was probably influenced by at least two factors. First, when both species nested on the platform, nest densities were higher than is typical of their colonies on larger, earthen islands, and colony success may have been reduced by overcrowding. Second, lack of access to water may have reduced chicks' ability to thermoregulate effectively in the hot environment of the Salton Sea. Refinements to the size, design, and location of artificial nesting habitats are necessary to enhance productivity of colonial groundnesting birds at the Salton Sea successfully.

Elevated temperatures are associated with stress in rooftop-nesting Common Nighthawk (Chordeiles minor) chicks.

PubMed

Newberry, Gretchen N; Swanson, David L

2018-01-01

Grasslands and riparian forests in southeastern South Dakota have been greatly reduced since historical times, primarily due to conversion to row-crop agriculture. Common Nighthawk ( Chordeiles minor ) nesting habitat includes grasslands, open woodlands and urban rooftops, but nesting sites in southeastern South Dakota are confined to rooftops, as natural nesting habitat is limited. Nighthawks nesting on exposed rooftop habitats may encounter thermal conditions that increase operative temperatures relative to vegetated land cover types. Mean humidity has increased and mean wind speed and cloud cover have decreased during the nighthawk breeding season from 1948 to 2016 in southeastern South Dakota. These changes might contribute to increasing operative temperatures at exposed rooftop nest sites and this could influence chick condition. We studied nest micro-climate and the plasma stress response for 24 rooftop-nesting nighthawk chicks from 17 nests during 2015 and 2016. High humidity prior to blood collection reduced both baseline and stress-induced plasma corticosterone (CORT). In contrast, high maximum temperatures during the day before sampling increased stress-induced CORT. The magnitude of the chick stress response was significantly negatively related to maximum wind speed for the week prior to CORT measurement. Other weather and micro-climate variables were not significant effectors of CORT metrics. Most chicks had low baseline CORT and were able to mount a stress response, but a subset of chicks ( n = 4) showed elevated baseline CORT and a negative association between the magnitude of stress response and ambient temperature. For this subset, mean ambient temperature for the day before sampling was significantly higher (2.3°C) than for chicks with typical baseline CORT levels. These data suggest that regional climate change trends could affect the ability of nighthawk chicks to mount a stress response, which, in turn, might influence the susceptibility of nighthawk chicks to climate change in the Northern Prairie region.

Predictive habitat models derived from nest-box occupancy for the endangered Carolina northern flying squirrel in the southern Appalachians

Treesearch

W. Mark Ford; Andrew M. Evans; Richard H. Odom; Jane L. Rodrigue; Christine A. Kelly; Nicole Abaid; Corinne A. Diggins; Douglas Newcomb

2015-01-01

In the southern Appalachians, artificial nest-boxes are used to survey for the endangered Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus), a disjunct subspecies associated with high elevation (>1385 m) forests. Using environmental parameters diagnostic of squirrel habitat, we created 35 a priori occupancy...

Methods for excluding cliff swallows from nesting on highway structures.

DOT National Transportation Integrated Search

2009-08-01

Cliff swallows (Petrochelidon pyrrhonota) are colonially breeding migratory birds that frequently nest on highway : structures. Protected by the Migratory Bird Treaty Act of 1918, nesting control methods cannot harm swallows or active : nests. This c...

Can hedgerow management mitigate the impacts of predation on songbird nest survival?

PubMed

Dunn, Jenny C; Gruar, Derek; Stoate, Chris; Szczur, John; Peach, Will J

2016-12-15

Nest predators can have significant impacts on songbird reproductive success. These impacts may be amplified by habitat simplification and here we test whether sympathetic management of farmland hedgerows can reduce nest depredation, especially by corvids. We test whether songbirds select nest sites according to structural features of hedgerows (including nest visibility and accessibility), and whether these features influence nest predation risk. Songbirds selected nesting sites affording higher vegetation cover above the nest, increased visibility on the nest-side of the hedgerow and reduced visibility on the far side of the hedge. Nest survival was unrelated to corvid abundance and only weakly related (at the egg stage) to corvid nest proximity. Nest survival at the chick stage was higher where vegetation structure restricted access to corvid-sized predators (averaging 0.78 vs. 0.53), and at nests close to potential vantage points. Overall nest survival was sensitive to hedgerow structure (accessibility) particularly at low exposure to corvid predation, while the overall impact of corvid exposure was dependent on the relationship involving proximity to vantage points. Nest survival over the chick stage was much higher (0.67) in stock-proof, trimmed and mechanically cut hedgerows, (which tended to provide lower side visibility and accessibility) than in recently laid, remnant or leggy hedgerows (0.18). Long-term reductions in the management of British hedgerows may therefore be exposing nesting songbirds to increased predation risk. We recommend regular rotational cutting of hedgerows to maintain a dense woody structure and thereby reduce songbird nest predation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Variability in vegetation effects on density and nesting success of grassland birds

USGS Publications Warehouse

Winter, Maiken; Johnson, Douglas H.; Shaffer, Jill A.

2005-01-01

The structure of vegetation in grassland systems, unlike that in forest systems, varies dramatically among years on the same sites, and among regions with similar vegetation. The role of this variation in vegetation structure on bird density and nesting success of grassland birds is poorly understood, primarily because few studies have included sufficiently large temporal and spatial scales to capture the variation in vegetation structure, bird density, or nesting success. To date, no large-scale study on grassland birds has been conducted to investigate whether grassland bird density and nesting success respond similarly to changes in vegetation structure. However, reliable management recommendations require investigations into the distribution and nesting success of grassland birds over larger temporal and spatial scales. In addition, studies need to examine whether bird density and nesting success respond similarly to changing environmental conditions. We investigated the effect of vegetation structure on the density and nesting success of 3 grassland-nesting birds: clay-colored sparrow (Spizella pallida), Savannah sparrow (Passerculus sandwichensis), and bobolink (Dolichonyx oryzivorus) in 3 regions of the northern tallgrass prairie in 1998-2001. Few vegetation features influenced the densities of our study species, and each species responded differently to those vegetation variables. We could identify only 1 variable that clearly influenced nesting success of 1 species: clay-colored sparrow nesting success increased with increasing percentage of nest cover from the surrounding vegetation. Because responses of avian density and nesting success to vegetation measures varied among regions, years, and species, land managers at all times need to provide grasslands with different types of vegetation structure. Management guidelines developed from small-scale, short-term studies may lead to misrepresentations of the needs of grassland-nesting birds.

California gull chicks raised near colony edges have elevated stress levels

USGS Publications Warehouse

Herring, Garth; Ackerman, Joshua T.

2011-01-01

Coloniality in nesting birds represents an important life history strategy for maximizing reproductive success. Birds nesting near the edge of colonies tend to have lower reproductive success than individuals nesting near colony centers, and offspring of edge-nesting parents may be impaired relative to those of central-nesting parents. We used fecal corticosterone metabolites in California gull chicks (Larus californicus) to examine whether colony size or location within the colony influenced a chick's physiological condition. We found that chicks being raised near colony edges had higher fecal corticosterone metabolite concentrations than chicks raised near colony centers, but that colony size (ranging from 150 to 11,554 nests) had no influence on fecal corticosterone levels. Fecal corticosterone metabolite concentrations also increased with chick age. Our results suggest that similarly aged California gull chicks raised near colony edges may be more physiologically stressed, as indicated by corticosterone metabolites, than chicks raised near colony centers.

Potential Influences of Climate and Nest Structure on Spotted Owl Reproductive Success: A Biophysical Approach

PubMed Central

Rockweit, Jeremy T.; Franklin, Alan B.; Bakken, George S.; Gutiérrez, R. J.

2012-01-01

Many bird species do not make their own nests; therefore, selection of existing sites that provide adequate microclimates is critical. This is particularly true for owls in north temperate climates that often nest early in the year when inclement weather is common. Spotted owls use three main types of nest structures, each of which are structurally distinct and may provide varying levels of protection to the eggs or young. We tested the hypothesis that spotted owl nest configuration influences nest microclimate using both experimental and observational data. We used a wind tunnel to estimate the convective heat transfer coefficient (hc) of eggs in 25 potential nest configurations that mimicked 2 nest types (top-cavity and platform nests), at 3 different wind speeds. We then used the estimates of hc in a biophysical heat transfer model to estimate how long it would take unattended eggs to cool from incubation temperature (∼36°C) to physiological zero temperature (PZT; ∼26°C) under natural environmental conditions. Our results indicated that the structural configuration of nests influences the cooling time of the eggs inside those nests, and hence, influences the nest microclimate. Estimates of time to PZT ranged from 10.6 minutes to 33.3 minutes. Nest configurations that were most similar to platform nests always had the fastest egg cooling times, suggesting that platform nests were the least protective of those nests we tested. Our field data coupled with our experimental results suggested that nest choice is important for the reproductive success of owls during years of inclement weather or in regions characterized by inclement weather during the nesting season. PMID:22859993

Ecological consequences of colony structure in dynamic ant nest networks.

PubMed

Ellis, Samuel; Franks, Daniel W; Robinson, Elva J H

2017-02-01

Access to resources depends on an individual's position within the environment. This is particularly important to animals that invest heavily in nest construction, such as social insects. Many ant species have a polydomous nesting strategy: a single colony inhabits several spatially separated nests, often exchanging resources between the nests. Different nests in a polydomous colony potentially have differential access to resources, but the ecological consequences of this are unclear. In this study, we investigate how nest survival and budding in polydomous wood ant ( Formica lugubris ) colonies are affected by being part of a multi-nest system. Using field data and novel analytical approaches combining survival models with dynamic network analysis, we show that the survival and budding of nests within a polydomous colony are affected by their position in the nest network structure. Specifically, we find that the flow of resources through a nest, which is based on its position within the wider nest network, determines a nest's likelihood of surviving and of founding new nests. Our results highlight how apparently disparate entities in a biological system can be integrated into a functional ecological unit. We also demonstrate how position within a dynamic network structure can have important ecological consequences.

Genetic variation, multiple paternity, and measures of reproductive success in the critically endangered hawksbill turtle (Eretmochelys imbricata).

PubMed

González-Garza, Blanca Idalia; Stow, Adam; Sánchez-Teyer, Lorenzo Felipe; Zapata-Pérez, Omar

2015-12-01

The Yucatán Peninsula in Mexico contains some of the largest breeding groups of the globally distributed and critically endangered hawksbill turtle (Eretmochelys imbricata). An improved understanding of the breeding system of this species and how its genetic variation is structured among nesting areas is required before the threats to its survival can be properly evaluated. Here, we genotype 1195 hatchlings and 41 nesting females at 12 microsatellite loci to assess levels of multiple paternity, genetic variation and whether individual levels of homozygosity are associated with reproductive success. Of the 50 clutches analyzed, only 6% have multiple paternity. The distribution of pairwise relatedness among nesting localities (rookeries) was not random with elevated within-rookery relatedness, and declining relatedness with geographic distance indicating some natal philopatry. Although there was no strong evidence that particular rookeries had lost allelic variation via drift, younger turtles had significantly lower levels of genetic variation than older turtles, suggesting some loss of genetic variation. At present there is no indication that levels of genetic variation are associated with measures of reproductive success such as clutch size, hatching success, and frequency of infertile eggs.

Ocean acidification affects fish spawning but not paternity at CO2 seeps.

PubMed

Milazzo, Marco; Cattano, Carlo; Alonzo, Suzanne H; Foggo, Andrew; Gristina, Michele; Rodolfo-Metalpa, Riccardo; Sinopoli, Mauro; Spatafora, Davide; Stiver, Kelly A; Hall-Spencer, Jason M

2016-07-27

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher risk of sperm competition found at elevated CO2, we also found a trend of lower satellite and sneaker male paternity at elevated CO2 Given the importance of fish for food security and ecosystem stability, this study highlights the need for targeted research into the effects of rising CO2 levels on patterns of reproduction in wild fish. © 2016 The Author(s).

Ocean acidification affects fish spawning but not paternity at CO2 seeps

PubMed Central

Cattano, Carlo; Alonzo, Suzanne H.; Foggo, Andrew; Gristina, Michele; Rodolfo-Metalpa, Riccardo; Sinopoli, Mauro; Spatafora, Davide; Stiver, Kelly A.; Hall-Spencer, Jason M.

2016-01-01

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher risk of sperm competition found at elevated CO2, we also found a trend of lower satellite and sneaker male paternity at elevated CO2. Given the importance of fish for food security and ecosystem stability, this study highlights the need for targeted research into the effects of rising CO2 levels on patterns of reproduction in wild fish. PMID:27466451

The evolution of cerebellum structure correlates with nest complexity.

PubMed

Hall, Zachary J; Street, Sally E; Healy, Susan D

2013-01-01

Across the brains of different bird species, the cerebellum varies greatly in the amount of surface folding (foliation). The degree of cerebellar foliation is thought to correlate positively with the processing capacity of the cerebellum, supporting complex motor abilities, particularly manipulative skills. Here, we tested this hypothesis by investigating the relationship between cerebellar foliation and species-typical nest structure in birds. Increasing complexity of nest structure is a measure of a bird's ability to manipulate nesting material into the required shape. Consistent with our hypothesis, avian cerebellar foliation increases as the complexity of the nest built increases, setting the scene for the exploration of nest building at the neural level.

Daily survival rate and habitat characteristics of nests of Wilson's Plover

USGS Publications Warehouse

Zinsser, Elizabeth; Sanders, Felicia J.; Gerard, Patrick D.; Jodice, Patrick G.R.

2017-01-01

We assessed habitat characteristics and measured daily survival rate of 72 nests of Charadrius wilsonia (Wilson's Plover) during 2012 and 2013 on South Island and Sand Island on the central coast of South Carolina. At both study areas, nest sites were located at slightly higher elevations (i.e., small platforms of sand) relative to randomly selected nearby unused sites, and nests at each study area also appeared to be situated to enhance crypsis and/or vigilance. Daily survival rate (DSR) of nests ranged from 0.969 to 0.988 among study sites and years, and the probability of nest survival ranged from 0.405 to 0.764. Flooding and predation were the most common causes of nest failure at both sites. At South Island, DSR was most strongly related to maximum tide height, which suggests that flooding and overwash may be common causes of nest loss for Wilson's Plovers at these study sites. The difference in model results between the 2 nearby study sites may be partially due to more-frequent flooding at Sand Island because of some underlying yet unmeasured physiographic feature. Remaining data gaps for the species include regional assessments of nest and chick survival and habitat requirements during chick rearing.

Suicide by people in a community justice pathway: population-based nested case–control study

PubMed Central

King, Carlene; Senior, Jane; Webb, Roger T.; Millar, Tim; Piper, Mary; Pearsall, Alison; Humber, Naomi; Appleby, Louis; Shaw, Jenny

2015-01-01

The elevated risk of suicide in prison and after release is a well-recognised and serious problem. Despite this, evidence concerning community-based offenders' suicide risk is sparse. We conducted a population-based nested case–control study of all people in a community justice pathway in England and Wales. Our data show 13% of general population suicides were in community justice pathways before death. Suicide risks were highest among individuals receiving police cautions, and those having recent, or impending prosecution for sexual offences. Findings have implications for the training and practice of clinicians identifying and assessing suicidality, and offering support to those at elevated risk. PMID:26159602

Flower diversity and bee reproduction in an arid ecosystem.

PubMed

Dorado, Jimena; Vázquez, Diego P

2016-01-01

Diverse flower communities are more stable in floral resource production along the flowering season, but the question about how the diversity and stability of resources affect pollinator reproduction remains open. High plant diversity could favor short foraging trips, which in turn would enhance bee fitness. In addition to plant diversity, greater temporal stability of floral resources in diverse communities could favor pollinator fitness because such communities are likely to occupy the phenological space more broadly, increasing floral availability for pollinators throughout the season. In addition, this potential effect of flower diversity on bee reproduction could be stronger for generalist pollinators because they can use a broader floral spectrum. Based on above arguments we predicted that pollinator reproduction would be positively correlated to flower diversity, and to temporal stability in flower production, and that this relationship would be stronger for the most generalized pollinator species. Using structural equation models, we evaluated the effect of these variables and other ecological factors on three estimates of bee reproduction (average number of brood cells per nest per site, total number of brood cells per site, and total number of nests per site), and whether such effects were modulated by bee generalization on floral resources. Contrary to our expectations, flower diversity had no effect on bee reproduction, stability in flower production had a weakly negative effect on one of the bee reproductive variables, and the strength of the fitness-diversity relationship was unrelated to bee generalization. In contrast, elevation had a negative effect on bee reproduction, despite the narrow elevation range encompassed by our sites. Flower diversity did not affect the reproduction of the solitary bees studied here. This result could stem from the context dependence of the diversity-stability relationship, given that elevation had a positive effect on flower diversity but a negative effect on bee reproduction. Although high temporal stability in flower production is expected to enhance pollinator reproduction, in our study it had a weakly negative-instead of positive-effect on the average number of brood cells per nest. Other environmental factors that vary with elevation could influence bee reproduction. Our study focused on a small group of closely-related bee species, which cautions against generalization of our findings to other groups of pollinators. More studies are clearly needed to assess the extent to which pollinator demography is influenced by the diversity of floral resources.

Leafcutter bee nests and pupae from the Rancho La Brea Tar Pits of Southern California: implications for understanding the paleoenvironment of the Late Pleistocene.

PubMed

Holden, Anna R; Koch, Jonathan B; Griswold, Terry; Erwin, Diane M; Hall, Justin

2014-01-01

The Rancho La Brea Tar Pits is the world's richest and most important Late Pleistocene fossil locality and best renowned for numerous fossil mammals and birds excavated over the past century. Less researched are insects, even though these specimens frequently serve as the most valuable paleoenvironemental indicators due to their narrow climate restrictions and life cycles. Our goal was to examine fossil material that included insect-plant associations, and thus an even higher potential for significant paleoenviromental data. Micro-CT scans of two exceptionally preserved leafcutter bee nest cells from the Rancho La Brea Tar Pits in Los Angeles, California reveal intact pupae dated between ∼23,000-40,000 radiocarbon years BP. Here identified as best matched to Megachile (Litomegachile) gentilis Cresson (Hymenoptera: Megachilidae) based on environmental niche models as well as morphometrics, the nest cells (LACMRLP 388E) document rare preservation and life-stage. The result of complex plant-insect interactions, they offer new insights into the environment of the Late Pleistocene in southern California. The remarkable preservation of the nest cells suggests they were assembled and nested in the ground where they were excavated. The four different types of dicotyledonous leaves used to construct the cells were likely collected in close proximity to the nest and infer a wooded or riparian habitat with sufficient pollen sources for larval provisions. LACMRLP 388E is the first record of fossil Megachile Latreille cells with pupae. Consequently, it provides a pre-modern age location for a Nearctic group, whose phylogenetic relationships and biogeographic history remain poorly understood. Megachile gentilis appears to respond to climate change as it has expanded its distribution across elevation gradients over time as estimated by habitat suitability comparisons between low and high elevations; it currently inhabits mesic habitats which occurred at a lower elevation during the Last Glacial Maximum ∼21,000 years ago. Nevertheless, the broad ecological niche of M. gentilis appears to have remained stable.

Leafcutter Bee Nests and Pupae from the Rancho La Brea Tar Pits of Southern California: Implications for Understanding the Paleoenvironment of the Late Pleistocene

PubMed Central

Holden, Anna R.; Koch, Jonathan B.; Griswold, Terry; Erwin, Diane M.; Hall, Justin

2014-01-01

The Rancho La Brea Tar Pits is the world’s richest and most important Late Pleistocene fossil locality and best renowned for numerous fossil mammals and birds excavated over the past century. Less researched are insects, even though these specimens frequently serve as the most valuable paleoenvironemental indicators due to their narrow climate restrictions and life cycles. Our goal was to examine fossil material that included insect-plant associations, and thus an even higher potential for significant paleoenviromental data. Micro-CT scans of two exceptionally preserved leafcutter bee nest cells from the Rancho La Brea Tar Pits in Los Angeles, California reveal intact pupae dated between ∼23,000–40,000 radiocarbon years BP. Here identified as best matched to Megachile (Litomegachile) gentilis Cresson (Hymenoptera: Megachilidae) based on environmental niche models as well as morphometrics, the nest cells (LACMRLP 388E) document rare preservation and life-stage. The result of complex plant-insect interactions, they offer new insights into the environment of the Late Pleistocene in southern California. The remarkable preservation of the nest cells suggests they were assembled and nested in the ground where they were excavated. The four different types of dicotyledonous leaves used to construct the cells were likely collected in close proximity to the nest and infer a wooded or riparian habitat with sufficient pollen sources for larval provisions. LACMRLP 388E is the first record of fossil Megachile Latreille cells with pupae. Consequently, it provides a pre-modern age location for a Nearctic group, whose phylogenetic relationships and biogeographic history remain poorly understood. Megachile gentilis appears to respond to climate change as it has expanded its distribution across elevation gradients over time as estimated by habitat suitability comparisons between low and high elevations; it currently inhabits mesic habitats which occurred at a lower elevation during the Last Glacial Maximum ∼21,000 years ago. Nevertheless, the broad ecological niche of M. gentilis appears to have remained stable. PMID:24718701

Dual response to nest flooding during monsoon in an Indian ant

PubMed Central

Kolay, Swetashree; Annagiri, Sumana

2015-01-01

Flooding causes destruction of shelter and disruption of activity in animals occupying subterranean nests. To ensure their survival organisms have evolved various responses to combat this problem. In this study we examine the response of an Indian ant, Diacamma indicum, to nest flooding during the monsoon season. Based on characterization of nest location, architecture and the response of these ants to different levels of flooding in their natural habitat as well as in the laboratory, we infer that they exhibit a dual response. On the one hand, the challenges presented by monsoon are dealt with by occupying shallow nests and modifying the entrance with decorations and soil mounds. On the other hand, inundated nests are evacuated and the ants occupy shelters at higher elevations. We conclude that focused studies of the monsoon biology of species that dwell in such climatic conditions may help us appreciate how organisms deal with, and adapt to, extreme seasonal changes. PMID:26349015

NASA airborne laser altimetry and ICESat-2 post-launch data validation

NASA Astrophysics Data System (ADS)

Brunt, K. M.; Neumann, T.; Studinger, M.; Hawley, R. L.; Markus, T.

2016-12-01

A series of NASA airborne lidars have made repeated surveys over an 11,000-m ground-based kinematic GPS traverse near Summit Station, Greenland. These ground-based data were used to assess the surface elevation bias and measurement precision of two airborne laser altimeters: Airborne Topographic Mapper (ATM) and Land, Vegetation, and Ice Sensor (LVIS). Data from the ongoing monthly traverses allowed for the assessment of 8 airborne lidar campaigns; elevation biases for these altimeters were less than 12.2 cm, while assessments of surface measurement precision were less than 9.1 cm. Results from the analyses of the Greenland ground-based GPS and airborne lidar data provide guidance for validation strategies for Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) elevation and elevation-change data products. Specifically, a nested approach to validation is required, where ground-based GPS data are used to constrain the bias and measurement precision of the airborne lidar data; airborne surveys can then be designed and conducted on longer length-scales to provide the amount of airborne data required to make more statistically meaningful assessments of satellite elevation data. This nested validation approach will continue for the ground-traverse in Greenland; further, the ICESat-2 Project Science Office has plans to conduct similar coordinated ground-based and airborne data collection in Antarctica.

Nest Site Characteristics of Cavity Nesting Birds in Central Missouri

Treesearch

Jeffery D. Brawn; Bernice Tannenbaum; Keith E. Evans

1984-01-01

Two study sites in central Missouri oak-hickory forests were searched for nest sites of cavity nesting birds. Researchers located and measured 133 nests of 11 species. Cavity nesting bird habitat selection is affected by both snag characteristics and vegetation structure.

The Need of Nested Grids for Aerial and Satellite Images and Digital Elevation Models

NASA Astrophysics Data System (ADS)

Villa, G.; Mas, S.; Fernández-Villarino, X.; Martínez-Luceño, J.; Ojeda, J. C.; Pérez-Martín, B.; Tejeiro, J. A.; García-González, C.; López-Romero, E.; Soteres, C.

2016-06-01

Usual workflows for production, archiving, dissemination and use of Earth observation images (both aerial and from remote sensing satellites) pose big interoperability problems, as for example: non-alignment of pixels at the different levels of the pyramids that makes it impossible to overlay, compare and mosaic different orthoimages, without resampling them and the need to apply multiple resamplings and compression-decompression cycles. These problems cause great inefficiencies in production, dissemination through web services and processing in "Big Data" environments. Most of them can be avoided, or at least greatly reduced, with the use of a common "nested grid" for mutiresolution production, archiving, dissemination and exploitation of orthoimagery, digital elevation models and other raster data. "Nested grids" are space allocation schemas that organize image footprints, pixel sizes and pixel positions at all pyramid levels, in order to achieve coherent and consistent multiresolution coverage of a whole working area. A "nested grid" must be complemented by an appropriate "tiling schema", ideally based on the "quad-tree" concept. In the last years a "de facto standard" grid and Tiling Schema has emerged and has been adopted by virtually all major geospatial data providers. It has also been adopted by OGC in its "WMTS Simple Profile" standard. In this paper we explain how the adequate use of this tiling schema as common nested grid for orthoimagery, DEMs and other types of raster data constitutes the most practical solution to most of the interoperability problems of these types of data.

The Antsy Social Network: Determinants of Nest Structure and Arrangement in Asian Weaver Ants.

PubMed

Devarajan, Kadambari

2016-01-01

Asian weaver ants (Oecophylla smaragdina) are arboreal ants that are known to form mutualistic complexes with their host trees. They are eusocial ants that build elaborate nests in the canopy in tropical areas. A colony comprises of multiple nests, usually on multiple trees, and the boundaries of the colony may be difficult to identify. However, they provide the ideal model for studying group living in invertebrates since there are a definite number of nests for a given substrate, the tree. Here, we briefly examine the structure of the nests and the processes involved in the construction and maintenance of these nests. We have described the spatial arrangement of weaver ant nests on trees in two distinct tropical clusters, a few hundred kilometres apart in India. Measurements were made for 13 trees with a total of 71 nests in the two field sites. We have considered a host of biotic and abiotic factors that may be crucial in determining the location of the nesting site by Asian weaver ants. Our results indicate that tree characteristics and architecture followed by leaf features help determine nest location in Asian weaver ants. While environmental factors may not be as influential to nest arrangement, they seem to be important determinants of nest structure. The parameters that may be considered in establishing the nests could be crucial in picking the evolutionary drivers for colonial living in social organisms.

Nest size is predicted by female identity and the local environment in the blue tit (Cyanistes caeruleus), but is not related to the nest size of the genetic or foster mother

PubMed Central

Parker, Timothy H.; Griffith, Simon C.

2018-01-01

The potential for animals to respond to changing climates has sparked interest in intraspecific variation in avian nest structure since this may influence nest microclimate and protect eggs and offspring from inclement weather. However, there have been relatively few large-scale attempts to examine variation in nests or the determinates of individual variation in nest structure within populations. Using a set of mostly pre-registered analyses, we studied potential predictors of variation in the size of a large sample (803) of blue tit (Cyanistes caeruleus) nests across three breeding seasons at Wytham Woods, UK. While our pre-registered analyses found that individual females built very similar nests across years, there was no evidence in follow-up (post hoc) analyses that their nest size correlated to that of their genetic mother or, in a cross-fostering experiment, to the nest where they were reared. In further pre-registered analyses, spatial environmental variability explained nest size variability at relatively broad spatial scales, and especially strongly at the scale of individual nest boxes. Our study indicates that nest structure is a characteristic of individuals, but is not strongly heritable, indicating that it will not respond rapidly to selection. Explaining the within-individual and within-location repeatability we observed requires further study. PMID:29765658

Influence of habitat heterogeneity on distribution, occupancy patterns, and productivity of breeding peregrine falcons in central west Greenland

USGS Publications Warehouse

Wightman, C.; Fuller, Mark R.

2006-01-01

We used occupancy and productivity data collected at 67 cliffs used for nesting from 1972 to 1999 to assess patterns of distribution and nest-site selection in an increasing population of Peregrine Falcons (Falco peregrinus) in central West Greenland. Peregrine Falcons breeding at traditionally occupied cliffs used for nesting had significantly lower variation in productivity and thus these cliffs were better quality sites. This indicates that Peregrine Falcons occupied cliffs according to a pattern of despotic distribution. Falcons breeding at cliffs that were consistently occupied during the breeding season had higher average productivity and lower variation in productivity than falcons at inconsistently occupied cliffs, and thus consistent occupancy also was indicative of cliff quality. Features of high quality habitat included tall cliffs, greater change in elevation from the lowest point within 3 km of the cliff to the cliff top (elevation gain), and protection from weather on the eyrie ledge. Spacing of suitable and occupied cliffs also was an important feature, and the best cliffs generally were more isolated. Increased spacing was likely a mechanism for reducing intraspecific competition. Our results suggest that Peregrine Falcons use a resource defense strategy to compete for better quality habitats and may use spacing and physical features of a nest site to identify good quality breeding habitat.

Multilevel Dynamic Generalized Structured Component Analysis for Brain Connectivity Analysis in Functional Neuroimaging Data.

PubMed

Jung, Kwanghee; Takane, Yoshio; Hwang, Heungsun; Woodward, Todd S

2016-06-01

We extend dynamic generalized structured component analysis (GSCA) to enhance its data-analytic capability in structural equation modeling of multi-subject time series data. Time series data of multiple subjects are typically hierarchically structured, where time points are nested within subjects who are in turn nested within a group. The proposed approach, named multilevel dynamic GSCA, accommodates the nested structure in time series data. Explicitly taking the nested structure into account, the proposed method allows investigating subject-wise variability of the loadings and path coefficients by looking at the variance estimates of the corresponding random effects, as well as fixed loadings between observed and latent variables and fixed path coefficients between latent variables. We demonstrate the effectiveness of the proposed approach by applying the method to the multi-subject functional neuroimaging data for brain connectivity analysis, where time series data-level measurements are nested within subjects.

Hurricane disturbance benefits nesting American Oystercatchers (Haematopus palliatus)

USGS Publications Warehouse

Simons, Theodore R.; Schulte, Shiloh A.

2016-01-01

Coastal ecosystems are under increasing pressure from human activity, introduced species, sea level rise, and storm activity. Hurricanes are a powerful destructive force, but can also renew coastal habitats. In 2003, Hurricane Isabel altered the barrier islands of North Carolina, flattening dunes and creating sand flats. American Oystercatchers (Haematopus palliatus) are large shorebirds that inhabit the coastal zone throughout the year. Alternative survival models were evaluated for 699 American Oystercatcher nests on North Core Banks and South Core Banks, North Carolina, USA, from 1999–2007. Nest survival on North Core Banks increased from 0.170 (SE = 0.002) to 0.772 (SE = 0.090) after the hurricane, with a carry-over effect lasting 2 years. A simple year effects model described nest survival on South Core Banks. Habitat had no effect on survival except when the overall rate of nest survival was at intermediate levels (0.300–0.600), when nests on open flats survived at a higher rate (0.600; SE = 0.112) than nests in dune habitat (0.243; SE = 0.094). Predator activity declined on North Core Banks after the hurricane and corresponded with an increase in nest survival. Periodic years with elevated nest survival may offset low annual productivity and contribute to the stability of American Oystercatcher populations.

Lifespan Analyses of Forest Raptor Nests: Patterns of Creation, Persistence and Reuse

PubMed Central

Jiménez-Franco, María V.; Martínez, José E.; Calvo, José F.

2014-01-01

Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively). Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species), to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding attempts. PMID:24717935

Lifespan analyses of forest raptor nests: patterns of creation, persistence and reuse.

PubMed

Jiménez-Franco, María V; Martínez, José E; Calvo, José F

2014-01-01

Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively). Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species), to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding attempts.

Conceptual Model Development for Sea Turtle Nesting Habitat: Support for USACE Navigation Projects

DTIC Science & Technology

2015-08-01

regional values. • Beach Width: The width of the beach (m) defines the region from the shoreline to the dune toe . Loggerhead turtles tend to prefer...primary drivers of the model parameters. • Beach Elevation: Beach elevation (m) is measured from the shoreline to the dune toe . Elevation influences...mapping, and morphological features in combination with imagery-derived environmental parameters (i.e., dune vegetation) have not been attempted

Identifying Kittlitz's Murrelet nesting habitat in North America at the landscape scale

USGS Publications Warehouse

Felis, Jonathan J.; Kissling, Michelle L.; Kaler, Robb S.A.; Kenney, Leah A.; Lawonn, Matthew J.

2016-01-01

The Kittlitz's Murrelet (Brachyramphus brevirostris) is a small, non-colonial seabird endemic to marine waters of Alaska and eastern Russia that may have experienced significant population decline in recent decades, in part because of low reproductive success and terrestrial threats. Although recent studies have shed new light on Kittlitz's Murrelet nesting habitat in a few discrete areas, the location and extent of suitable nesting habitat throughout most of its range remains unclear. Here, we have compiled all existing nest records and locations to identify landscape-scale parameters (distance to coast, elevation, slope, and land cover) that provide potential nesting habitat in four regions: northern Alaska, Aleutian Islands, Alaska Peninsula Mountains and Kodiak Island, and Pacific Coastal Mountains (including nearshore interior Canada). We produced a final map classifying 12% (70,411 km2) of the lands assessed as potential Kittlitz's Murrelet nesting habitat, with dense but distinct patches in northern Alaska and a more uninterrupted, narrow band extending across the Pacific Coastal Mountains, Alaska Peninsula Mountains, and Aleutian Islands. The extent of habitat-capable parameter values varied regionally, indicating that the Kittlitz's Murrelet may be able to use a variety of habitats for nesting, depending on availability. Future nesting habitat studies could employ spatially random sampling designs to allow for quantitatively robust modeling of nesting habitat and predictive extrapolation to areas where nests have not been located but likely exist.

When social behaviour is moulded in clay: on growth and form of social insect nests.

PubMed

Perna, Andrea; Theraulaz, Guy

2017-01-01

The nests built by social insects are among the most complex structures produced by animal groups. They reveal the social behaviour of a colony and as such they potentially allow comparative studies. However, for a long time, research on nest architecture was hindered by the lack of technical tools allowing the visualisation of their complex 3D structures and the quantification of their properties. Several techniques, developed over the years, now make it possible to study the organisation of these nests and how they are built. Here, we review present knowledge of the mechanisms of nest construction, and how nest structure affects the behaviour of individual insects and the organisation of activities within a colony. © 2017. Published by The Company of Biologists Ltd.

Phenotypic plasticity of nest timing in a post-glacial landscape: how do reptiles adapt to seasonal time constraints?

PubMed

Edge, Christopher B; Rollinson, Njal; Brooks, Ronald J; Congdon, Justin D; Iverson, John B; Janzen, Fredric J; Litzgus, Jacqueline D

2017-02-01

Life histories evolve in response to constraints on the time available for growth and development. Nesting date and its plasticity in response to spring temperature may therefore be important components of fitness in oviparous ectotherms near their northern range limit, as reproducing early provides more time for embryos to complete development before winter. We used data collected over several decades to compare air temperature and nest date plasticity in populations of painted turtles and snapping turtles from a relatively warm environment (southeastern Michigan) near the southern extent of the last glacial maximum to a relatively cool environment (central Ontario) near the northern extent of post-glacial recolonization. For painted turtles, population-level differences in reaction norm elevation for two phenological traits were consistent with adaptation to time constraints, but no differences in reaction norm slopes were observed. For snapping turtle populations, the difference in reaction norm elevation for a single phenological trait was in the opposite direction of what was expected under adaptation to time constraints, and no difference in reaction norm slope was observed. Finally, among-individual variation in individual plasticity for nesting date was detected only in the northern population of snapping turtles, suggesting that reaction norms are less canalized in this northern population. Overall, we observed evidence of phenological adaptation, and possibly maladaptation, to time constraints in long-lived reptiles. Where present, (mal)adaptation occurred by virtue of differences in reaction norm elevation, not reaction norm slope. Glacial history, generation time, and genetic constraint may all play an important role in the evolution of phenological timing and its plasticity in long-lived reptiles. © 2016 by the Ecological Society of America.

Nest site characteristics of three coexisting Accipiter hawks in northeastern Oregon

USGS Publications Warehouse

Moore, K.R.; Henny, C.J.

1983-01-01

Habitat data were evaluated at 34 Goshawk (Accipiter gentilis), 31 Cooper's Hawk (A. cooperii), and 15 Sharp-shinned Hawk (A. striatus) nest sites in coniferous forests of northeastern Oregon. Crown volume profiles indicate a strong similarity in vegetative structure at nest sites of cooperii and striatus; both commonly nest in younger successional stands than gentilis. Habitat separation of nest sites among the three species was illustrated using a stepwise discriminant analysis; 88% of all gentilis sites were correctly classified. Interspecific overlap in nest site habitat was further demonstrated using a canonical analysis of habitat variables. Nest site habitat space of gentilis is distinct and is less variable in structure than that of the other species. Cooperii preferred nesting sites with norhern aspects, whereas striatus and gentilis showed no preference. The use of mistletoe (Arceuthobium sp.) growth by cooperii for nest platforms (64% of all nests) may explain its preference for Douglas fir (Pseudotsuga menziesii) as a nesting tree. Douglas fir is most commonly parasitized by mistletoe.

Nest survival of piping plovers at a dynamic reservoir indicates an ecological trap for a threatened population

USGS Publications Warehouse

Anteau, Michael J.; Shaffer, Terry L.; Sherfy, Mark H.; Sovada, Marsha A.; Stucker, Jennifer H.; Wiltermuth, Mark T.

2012-01-01

In the past 60 years, reservoirs have reshaped riverine ecosystems and transformed breeding habitats used by the threatened piping plover (Charadrius melodus; hereafter plover). Currently, 29% of the Northern Great Plains plover population nests at reservoirs that might function as ecological traps because reservoirs have more diverse habitat features and greater dynamics in water levels than habitats historically used by breeding plovers. We examined factors influencing daily survival rates (DSR) of 346 plover nests at Lake Sakakawea (SAK; reservoir) during 2006–2009 by evaluating multiple a priori models, and we used our best model to hindcast nest success of plovers during 1985–2009. Our observed and hindcast estimates of nest success were low compared to published estimates. Previous findings indicate that plovers prefer nest sites that are low relative to water level. We found that elevation of nests above the water level had a strong positive correlation with DSR because water levels of SAK typically increased throughout the nesting period. Habitat characteristics on the reservoir differ from those that shaped nest-site selection for plovers. Accordingly, extraordinary nest loss occurs there in many years, largely due to inundation of nests, and based on low fledging rates those losses were not compensated by potential changes in chick survival. Therefore, our example supports the concept of ecological traps in birds because it addresses quantitative assessments of habitat preference and productivity over 25 years (since species listing) and affects a large portion of the population.

Ultra-Fine Scale Spatially-Integrated Mapping of Habitat and Occupancy Using Structure-From-Motion.

PubMed

McDowall, Philip; Lynch, Heather J

2017-01-01

Organisms respond to and often simultaneously modify their environment. While these interactions are apparent at the landscape extent, the driving mechanisms often occur at very fine spatial scales. Structure-from-Motion (SfM), a computer vision technique, allows the simultaneous mapping of organisms and fine scale habitat, and will greatly improve our understanding of habitat suitability, ecophysiology, and the bi-directional relationship between geomorphology and habitat use. SfM can be used to create high-resolution (centimeter-scale) three-dimensional (3D) habitat models at low cost. These models can capture the abiotic conditions formed by terrain and simultaneously record the position of individual organisms within that terrain. While coloniality is common in seabird species, we have a poor understanding of the extent to which dense breeding aggregations are driven by fine-scale active aggregation or limited suitable habitat. We demonstrate the use of SfM for fine-scale habitat suitability by reconstructing the locations of nests in a gentoo penguin colony and fitting models that explicitly account for conspecific attraction. The resulting digital elevation models (DEMs) are used as covariates in an inhomogeneous hybrid point process model. We find that gentoo penguin nest site selection is a function of the topography of the landscape, but that nests are far more aggregated than would be expected based on terrain alone, suggesting a strong role of behavioral aggregation in driving coloniality in this species. This integrated mapping of organisms and fine scale habitat will greatly improve our understanding of fine-scale habitat suitability, ecophysiology, and the complex bi-directional relationship between geomorphology and habitat use.

Enclosed nests may provide greater thermal than nest predation benefits compared with open nests across latitudes

USGS Publications Warehouse

Martin, Thomas E.; Boyce, Andy J.; Fierro-Calderon, Karolina; Mitchell, Adam E.; Armstad, Connor E.; Mouton, James C.; Bin Soudi, Evertius E.

2017-01-01

Nest structure is thought to provide benefits that have fitness consequences for several taxa. Traditionally, reduced nest predation has been considered the primary benefit underlying evolution of nest structure, whereas thermal benefits have been considered a secondary or even non-existent factor. Yet, the relative roles of these factors on nest structures remain largely unexplored.Enclosed nests have a constructed or natural roof connected to sides that allow a restricted opening or tube entrance that provides cover in all directions except the entrance, whereas open nests are cups or platforms that are open above. We show that construction of enclosed nests is more common among songbirds (Passeriformes) in tropical and southern hemisphere regions than in north temperate regions. This geographic pattern may reflect selection from predation risk, under long-standing assumptions that nest predation rates are higher in southern regions and that enclosed nests reduce predation risk compared with open cup nests. We therefore compared nest predation rates between enclosed vs. open nests in 114 songbird species that do not nest in tree holes among five communities of coexisting birds, and for 205 non-hole-nesting species from the literature, across northern temperate, tropical, and southern hemisphere regions.Among coexisting species, enclosed nests had lower nest predation rates than open nests in two south temperate sites, but not in either of two tropical sites or a north temperate site. Nest predation did not differ between nest types at any latitude based on literature data. Among 319 species from both our field studies and the literature, enclosed nests did not show consistent benefits of reduced predation and, in fact, predation was not consistently higher in the tropics, contrary to long-standing perspectives.Thermal benefits of enclosed nests were indicated based on three indirect results. First, species that built enclosed nests were smaller than species using open nests both among coexisting species and among species from the literature. Smaller species lose heat fastest and thereby may gain important thermal benefits from reduced convective cooling. Second, eggs were warmed by parents for less time in species with enclosed nests, as can be expected if egg cooling rates are slower. Finally, species using enclosed nests exhibited enhanced growth of mass and wings compared with species using open nests, suggesting reduced thermoregulatory costs allowed increased energy for growth.Enclosed nests may therefore provide more consistent thermal than nest predation benefits, counter to long-standing perspectives.

New homes for prairie ducks

USGS Publications Warehouse

Doty, H.A.

1970-01-01

This pamphlet describes how to make, install and care for inexpensive duck nesting baskets. Ducks have been attracted to these structures in the prairies of eastern North and South Dakota, western Minnesota, and northern Iowa. Nesting structures can help increase the number of local nesting ducks, especially mallards.

Effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in Alberta, Canada

PubMed Central

Koper, Nicola

2017-01-01

Grassland songbird populations across North America have experienced dramatic population declines due to habitat loss and degradation. In Canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in North American mixed-grass prairies remains largely unknown. From 2010–2012, in southeastern Alberta, Canada, we monitored 257 nests of two ground-nesting grassland songbird species, Savannah sparrow (Passerculus sandwichensis) and chestnut-collared longspur (Calcarius ornatus). Nest locations varied with proximity to and density of conventional shallow gas well structures and associated roads in forty-two 258-ha mixed-grass prairie sites. We estimated the probabilities of nest success and clutch size relative to gas well structures and roads. There was little effect of distance to or density of gas well structure on nest success; however, Savannah sparrow experienced lower nest success near roads. Clutch sizes were lower near gas well structures and cattle water sources. Minimizing habitat disturbance surrounding gas well structures, and reducing abundance of roads and trails, would help minimize impacts on reproductive success for some grassland songbirds. PMID:28355241

Effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in Alberta, Canada.

PubMed

Yoo, Jenny; Koper, Nicola

2017-01-01

Grassland songbird populations across North America have experienced dramatic population declines due to habitat loss and degradation. In Canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in North American mixed-grass prairies remains largely unknown. From 2010-2012, in southeastern Alberta, Canada, we monitored 257 nests of two ground-nesting grassland songbird species, Savannah sparrow (Passerculus sandwichensis) and chestnut-collared longspur (Calcarius ornatus). Nest locations varied with proximity to and density of conventional shallow gas well structures and associated roads in forty-two 258-ha mixed-grass prairie sites. We estimated the probabilities of nest success and clutch size relative to gas well structures and roads. There was little effect of distance to or density of gas well structure on nest success; however, Savannah sparrow experienced lower nest success near roads. Clutch sizes were lower near gas well structures and cattle water sources. Minimizing habitat disturbance surrounding gas well structures, and reducing abundance of roads and trails, would help minimize impacts on reproductive success for some grassland songbirds.

Wetland and microhabitat use by nesting four-toed salamanders in Maine

USGS Publications Warehouse

Chalmers, R.J.; Loftin, C.S.

2006-01-01

Little is known of Four-Toed Salamander (Hemidactylium scutatum) habitat use, despite the species' extensive range and elevated conservation status. We investigated species-habitat relationships that predict H. scutatum nesting presence in Maine at wetland and microhabitat scales by comparing microhabitats with and without nests. We created logistic regression models, selected models with AIC, and evaluated models with reserve data. Wetlands with nests were best predicted by shoreline microhabitat of Sphagnum spp., wood substrate, water flow, blue-joint reed grass (Calamagrostis canadensis), meadowsweet (Spiraea alba), steeplebush (Spiraea tomentosa), sensitive fern (Onoclea sensibilis), and absence of sheep laurel (Kalmia angustifolia) or deciduous forest canopy. Within occupied wetlands, shoreline microhabitat where nests occurred was best distinguished from available, unoccupied shoreline microhabitat by steeper shore, greater near-shore and basin water depth, deeper nesting vegetation, presence of moss spp. and winterberry (Ilex verticillata), and a negative association with S. alba, leatherleaf (Chamaedaphne calyculata), and K. angustifolia. These models of wetland and microhabitat use by H. scutatum may assist ecologists and managers in detecting and conserving this species. Copyright 2006 Society for the Study of Amphibians and Reptiles.

Why are some plant-pollinator networks more nested than others?

PubMed

Song, Chuliang; Rohr, Rudolf P; Saavedra, Serguei

2017-10-01

Empirical studies have found that the mutualistic interactions forming the structure of plant-pollinator networks are typically more nested than expected by chance alone. Additionally, theoretical studies have shown a positive association between the nested structure of mutualistic networks and community persistence. Yet, it has been shown that some plant-pollinator networks may be more nested than others, raising the interesting question of which factors are responsible for such enhanced nested structure. It has been argued that ordered network structures may increase the persistence of ecological communities under less predictable environments. This suggests that nested structures of plant-pollinator networks could be more advantageous under highly seasonal environments. While several studies have investigated the link between nestedness and various environmental variables, unfortunately, there has been no unified answer to validate these predictions. Here, we move from the problem of describing network structures to the problem of comparing network structures. We develop comparative statistics, and apply them to investigate the association between the nested structure of 59 plant-pollinator networks and the temperature seasonality present in their locations. We demonstrate that higher levels of nestedness are associated with a higher temperature seasonality. We show that the previous lack of agreement came from an extended practice of using standardized measures of nestedness that cannot be compared across different networks. Importantly, our observations complement theory showing that more nested network structures can increase the range of environmental conditions compatible with species coexistence in mutualistic systems, also known as structural stability. This increase in nestedness should be more advantageous and occur more often in locations subject to random environmental perturbations, which could be driven by highly changing or seasonal environments. This synthesis of theory and observations could prove relevant for a better understanding of the ecological processes driving the assembly and persistence of ecological communities. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Greater sage-grouse nest predators in the Virginia Mountains of northwestern Nevada

USGS Publications Warehouse

Lockyer, Zachary B.; Coates, Peter S.; Casazza, Michael L.; Espinosa, Shawn; Delehanty, David J.

2013-01-01

Greater sage-grouse Centrocercus urophasianus, hereafter sage-grouse, populations have declined across their range due to the loss, degradation, and fragmentation of habitat. Habitat alterations can lead not only to vegetative changes but also to shifts in animal behavior and predator composition that may influence population vital rates, such as nest success. For example, common ravens Corvus corax are sage-grouse nest predators, and common raven abundance is positively associated with human-caused habitat alterations. Because nest success is a central component to sage-grouse population persistence, research that identifies factors influencing nest success will better inform conservation efforts. We used videography to unequivocally identify sage-grouse nest predators within the Virginia Mountains of northwestern Nevada, USA, from 2009 to 2011 and used maximum likelihood to calculate daily probability of nest survival. In the Virginia Mountains, fires, energy exploration, and other anthropogenic activities have altered historic sage-grouse habitat. We monitored 71 sage-grouse nests during the study, placing video cameras at 39 nests. Cumulative nest survival for all nests was 22.4% (95% CI, 13.0–33.4%), a survival rate that was significantly lower than other published results for sage-grouse in the Great Basin. Depredation was the primary cause for nest failure in our study (82.5%), and common ravens were the most frequent sage-grouse nest predator, accounting for 46.7% of nest depredations. We also successfully documented a suite of mammalian and reptilian species depredating sage-grouse nests, including some predators never previously confirmed in the literature to be sage-grouse nest predators (i.e., bobcats Lynx rufus and long-tailed weasels Mephitis frenata). Within the high elevation, disturbed habitat of the Virginia Mountains, low sage-grouse nest success may be limiting sage-grouse population growth. These results suggest that management actions that restore habitat in the Virginia Mountains and decrease anthropogenic subsidies of ravens will benefit sage-grouse.

Influence of habitat heterogeneity on distribution, occupancy patterns, and productivity of breeding peregrine falcons in central West Greenland

USGS Publications Warehouse

Wightman, C.S.; Fuller, M.R.

2006-01-01

We used occupancy and productivity data collected at 67 cliffs used for nesting from 1972 to 1999 to assess patterns of distribution and nest-site selection in an increasing population of Peregrine Falcons (Falco peregrinus) in central West Greenland. Peregrine Falcons breeding at traditionally occupied cliffs used for nesting had significantly lower variation in productivity and thus these cliffs were better quality sites. This indicates that Peregrine Falcons occupied cliffs according to a pattern of despotic distribution. Falcons breeding at cliffs that were consistently occupied during the breeding season had higher average productivity and lower variation in productivity than falcons at inconsistently occupied cliffs, and thus consistent occupancy also was indicative of cliff quality. Features of high quality habitat included tall cliffs, greater change in elevation from the lowest point within 3 km of the cliff to the cliff top (elevation gain), and protection from weather on the eyrie ledge. Spacing of suitable and occupied cliffs also was an important feature, and the best cliffs generally were more isolated. Increased spacing was likely a mechanism for reducing intraspecific competition. Our results suggest that Peregrine Falcons use a resource defense strategy to compete for better quality habitats and may use spacing and physical features of a nest site to identify good quality breeding habitat. ?? The Cooper Ornithological Society 2006.

Influence of an extreme high water event on survival, reproduction, and distribution of snail kites in Florida, USA

USGS Publications Warehouse

Bennetts, R.E.; Kitchens, W.M.; Dreitz, V.J.

2002-01-01

Hydrology frequently has been reported as the environmental variable having the greatest influence on Florida snail kite (Rostrhamus sociabilis) populations. Although drought has received the most attention, high-water conditions also have been reported to affect kites. Years of high water generally have been reported to be favorable for nesting, although prolonged high water may be detrimental to sustaining suitable habitat. During 1994 and 1995, southern Florida experienced an extreme high water event. This event enabled us to compare survival, nesting success, number of young per successful nest, and spatial distribution of nesting before, during, and after the event. We found no evidence of an effect (either negative or positive) on survival of adult kites. In contrast, juvenile kites experienced the highest survival during the event, although our data suggest greater annual variability than can be explained by the event alone. We found no evidence of an effect of the high water event on nest success or number of young per successful nest. Nest success was highest during the event in the southern portion of the range but was quite similar to other years, both before and after the event. Our data do indicate a substantial shift in the spatial distribution of nesting birds. During the event, nesting activity shifted to higher elevations (i.e., shallower water) in the major nesting areas of the Everglades region. Nesting also occurred in Big Cypress National Preserve during the event, which is typically too dry to support nesting kites. Thus, our data indicate a potential short-term benefit of increased juvenile survival and an expansion of nesting habitat. However, the deterioration of habitat quality from prolonged high water precludes any recommendation for such conditions to be maintained for extended periods. ?? 2002, The Society of Wetland Scientists.

Response of Brown Creepers to elevation and forest edges in the southern Sierra Nevada, California

Treesearch

Kathryn Purcell; Craig Thompson; Douglas Drynan

2012-01-01

We studied the responses of the Brown Creeper (Certhia americana) to forest edges in the southern Sierra Nevada, California. We censused birds and monitored nests in four forest types over an elevational gradient. We identified habitat patches homogeneous in terms of forest type, seral stage, and canopy cover and rated edges between adjoining...

Flower diversity and bee reproduction in an arid ecosystem

PubMed Central

Vázquez, Diego P.

2016-01-01

Background: Diverse flower communities are more stable in floral resource production along the flowering season, but the question about how the diversity and stability of resources affect pollinator reproduction remains open. High plant diversity could favor short foraging trips, which in turn would enhance bee fitness. In addition to plant diversity, greater temporal stability of floral resources in diverse communities could favor pollinator fitness because such communities are likely to occupy the phenological space more broadly, increasing floral availability for pollinators throughout the season. In addition, this potential effect of flower diversity on bee reproduction could be stronger for generalist pollinators because they can use a broader floral spectrum. Based on above arguments we predicted that pollinator reproduction would be positively correlated to flower diversity, and to temporal stability in flower production, and that this relationship would be stronger for the most generalized pollinator species. Materials and Methods: Using structural equation models, we evaluated the effect of these variables and other ecological factors on three estimates of bee reproduction (average number of brood cells per nest per site, total number of brood cells per site, and total number of nests per site), and whether such effects were modulated by bee generalization on floral resources. Results: Contrary to our expectations, flower diversity had no effect on bee reproduction, stability in flower production had a weakly negative effect on one of the bee reproductive variables, and the strength of the fitness-diversity relationship was unrelated to bee generalization. In contrast, elevation had a negative effect on bee reproduction, despite the narrow elevation range encompassed by our sites. Discussion: Flower diversity did not affect the reproduction of the solitary bees studied here. This result could stem from the context dependence of the diversity-stability relationship, given that elevation had a positive effect on flower diversity but a negative effect on bee reproduction. Although high temporal stability in flower production is expected to enhance pollinator reproduction, in our study it had a weakly negative—instead of positive—effect on the average number of brood cells per nest. Other environmental factors that vary with elevation could influence bee reproduction. Our study focused on a small group of closely-related bee species, which cautions against generalization of our findings to other groups of pollinators. More studies are clearly needed to assess the extent to which pollinator demography is influenced by the diversity of floral resources. PMID:27547556

The structure of gallery networks in the nests of termite Cubitermes spp. revealed by X-ray tomography

NASA Astrophysics Data System (ADS)

Perna, Andrea; Jost, Christian; Couturier, Etienne; Valverde, Sergi; Douady, Stéphane; Theraulaz, Guy

2008-09-01

Recent studies have introduced computer tomography (CT) as a tool for the visualisation and characterisation of insect architectures. Here, we use CT to map the three-dimensional networks of galleries inside Cubitermes nests in order to analyse them with tools from graph theory. The structure of these networks indicates that connections inside the nest are rearranged during the whole nest life. The functional analysis reveals that the final network topology represents an excellent compromise between efficient connectivity inside the nest and defence against attacking predators. We further discuss and illustrate the usefulness of CT to disentangle environmental and specific influences on nest architecture.

Evidence that Magnetic Navigation and Geomagnetic Imprinting Shape Spatial Genetic Variation in Sea Turtles.

PubMed

Brothers, J Roger; Lohmann, Kenneth J

2018-04-23

The canonical drivers of population genetic structure, or spatial genetic variation, are isolation by distance and isolation by environment. Isolation by distance predicts that neighboring populations will be genetically similar and geographically distant populations will be genetically distinct [1]. Numerous examples also exist of isolation by environment, a phenomenon in which populations that inhabit similar environments (e.g., same elevation, temperature, or vegetation) are genetically similar even if they are distant, whereas populations that inhabit different environments are genetically distinct even when geographically close [2-4]. These dual models provide a widely accepted conceptual framework for understanding population structure [5-8]. Here, we present evidence for an additional, novel process that we call isolation by navigation, in which the navigational mechanism used by a long-distance migrant influences population structure independently of isolation by either distance or environment. Specifically, we investigated the population structure of loggerhead sea turtles (Caretta caretta) [9], which return to nest on their natal beaches by seeking out unique magnetic signatures along the coast-a behavior known as geomagnetic imprinting [10-12]. Results reveal that spatial variation in Earth's magnetic field strongly predicts genetic differentiation between nesting beaches, even when environmental similarities and geographic proximity are taken into account. The findings provide genetic corroboration of geomagnetic imprinting [10, 13]. Moreover, they provide strong evidence that geomagnetic imprinting and magnetic navigation help shape the population structure of sea turtles and perhaps numerous other long-distance migrants that return to their natal areas to reproduce [13-17]. Copyright © 2018 Elsevier Ltd. All rights reserved.

Physical cognition: birds learn the structural efficacy of nest material

PubMed Central

Bailey, Ida E.; Morgan, Kate V.; Bertin, Marion; Meddle, Simone L.; Healy, Susan D.

2014-01-01

It is generally assumed that birds’ choice of structurally suitable materials for nest building is genetically predetermined. Here, we tested that assumption by investigating whether experience affected male zebra finches’ (Taeniopygia guttata) choice of nest material. After a short period of building with relatively flexible string, birds preferred to build with stiffer string while those that had experienced a stiffer string were indifferent to string type. After building a complete nest with either string type, however, all birds increased their preference for stiff string. The stiffer string appeared to be the more effective building material as birds required fewer pieces of stiffer than flexible string to build a roofed nest. For birds that raised chicks successfully, there was no association between the material they used to build their nest and the type they subsequently preferred. Birds’ material preference reflected neither the preference of their father nor of their siblings but juvenile experience of either string type increased their preference for stiffer string. Our results represent two important advances: (i) birds choose nest material based on the structural properties of the material; (ii) nest material preference is not entirely genetically predetermined as both the type and amount of experience influences birds’ choices. PMID:24741011

Physical cognition: birds learn the structural efficacy of nest material.

PubMed

Bailey, Ida E; Morgan, Kate V; Bertin, Marion; Meddle, Simone L; Healy, Susan D

2014-06-07

It is generally assumed that birds' choice of structurally suitable materials for nest building is genetically predetermined. Here, we tested that assumption by investigating whether experience affected male zebra finches' (Taeniopygia guttata) choice of nest material. After a short period of building with relatively flexible string, birds preferred to build with stiffer string while those that had experienced a stiffer string were indifferent to string type. After building a complete nest with either string type, however, all birds increased their preference for stiff string. The stiffer string appeared to be the more effective building material as birds required fewer pieces of stiffer than flexible string to build a roofed nest. For birds that raised chicks successfully, there was no association between the material they used to build their nest and the type they subsequently preferred. Birds' material preference reflected neither the preference of their father nor of their siblings but juvenile experience of either string type increased their preference for stiffer string. Our results represent two important advances: (i) birds choose nest material based on the structural properties of the material; (ii) nest material preference is not entirely genetically predetermined as both the type and amount of experience influences birds' choices.

The design and function of birds' nests

PubMed Central

Mainwaring, Mark C; Hartley, Ian R; Lambrechts, Marcel M; Deeming, D Charles

2014-01-01

All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build structures that are extended phenotypic signals whose sole purpose is to attract a mate, nests contain eggs and/or offspring, thereby suggesting a direct trade-off between the conflicting requirements of natural and sexual selection. Nest design also varies adaptively in order to both minimize the detrimental effects of parasites and to create a suitable microclimate for parents and developing offspring in relation to predictable variation in environmental conditions. Our understanding of the design and function of birds' nests has increased considerably in recent years, and the evidence suggests that nests have four nonmutually exclusive functions. Consequently, we conclude that the design of birds' nests is far more sophisticated than previously realized and that nests are multifunctional structures that have important fitness consequences for the builder/s. PMID:25505520

Geographic variation in patterns of nestedness among local stream fish assemblages in Virginia

USGS Publications Warehouse

Cook, R.R.; Angermeier, P.L.; Finn, D.S.; Poff, N.L.; Krueger, K.L.

2004-01-01

Nestedness of faunal assemblages is a multiscale phenomenon, potentially influenced by a variety of factors. Prior small-scale studies have found freshwater fish species assemblages to be nested along stream courses as a result of either selective colonization or extinction. However, within-stream gradients in temperature and other factors are correlated with the distributions of many fish species and may also contribute to nestedness. At a regional level, strongly nested patterns would require a consistent set of structuring mechanisms across streams, and correlation among species' tolerances of the environmental factors that influence distribution. Thus, nestedness should be negatively associated with the spatial extent of the region analyzed and positively associated with elevational gradients (a correlate of temperature and other environmental factors). We examined these relationships for the freshwater fishes of Virginia. Regions were defined within a spatial hierarchy and included whole river drainages, portions of drainages within physiographic provinces, and smaller subdrainages. In most cases, nestedness was significantly stronger in regions of smaller spatial extent and in regions characterized by greater topographic relief. Analysis of hydrologic variability and patterns of faunal turnover provided no evidence that interannual colonization/extinction dynamics contributed to elevational differences in nestedness. These results suggest that, at regional scales, nestedness is influenced by interactions between biotic and abiotic factors, and that the strongest nestedness is likely to occur where a small number of organizational processes predominate, i.e., over small spatial extents and regions exhibiting strong environmental gradients. ?? Springer-Verlag 2004.

Where to nest? Ecological determinants of chimpanzee nest abundance and distribution at the habitat and tree species scale.

PubMed

Carvalho, Joana S; Meyer, Christoph F J; Vicente, Luis; Marques, Tiago A

2015-02-01

Conversion of forests to anthropogenic land-uses increasingly subjects chimpanzee populations to habitat changes and concomitant alterations in the plant resources available to them for nesting and feeding. Based on nest count surveys conducted during the dry season, we investigated nest tree species selection and the effect of vegetation attributes on nest abundance of the western chimpanzee, Pan troglodytes verus, at Lagoas de Cufada Natural Park (LCNP), Guinea-Bissau, a forest-savannah mosaic widely disturbed by humans. Further, we assessed patterns of nest height distribution to determine support for the anti-predator hypothesis. A zero-altered generalized linear mixed model showed that nest abundance was negatively related to floristic diversity (exponential form of the Shannon index) and positively with the availability of smaller-sized trees, reflecting characteristics of dense-canopy forest. A positive correlation between nest abundance and floristic richness (number of plant species) and composition indicated that species-rich open habitats are also important in nest site selection. Restricting this analysis to feeding trees, nest abundance was again positively associated with the availability of smaller-sized trees, further supporting the preference for nesting in food tree species from dense forest. Nest tree species selection was non-random, and oil palms were used at a much lower proportion (10%) than previously reported from other study sites in forest-savannah mosaics. While this study suggests that human disturbance may underlie the exclusive arboreal nesting at LCNP, better quantitative data are needed to determine to what extent the construction of elevated nests is in fact a response to predators able to climb trees. Given the importance of LCNP as refuge for Pan t. verus our findings can improve conservation decisions for the management of this important umbrella species as well as its remaining suitable habitats. © 2014 Wiley Periodicals, Inc.

Does survey method bias the description of northern goshawk nest-site structure?

USGS Publications Warehouse

Daw, S.K.; DeStefano, S.; Steidl, R.J.

1998-01-01

Past studies on the nesting habitat of northern goshawks (Accipiter gentilis) often relied on nests found opportunistically, either during timber-sale operations, by searching apparently 'good' goshawk habitat, or by other search methods where areas were preselected based on known forest conditions. Therefore, a bias in the characterization of habitat surrounding northern goshawk nest sites may exist toward late-forest structure (large trees, high canopy closure). This potential problem has confounded interpretation of data on nesting habitat of northern goshawks and added to uncertainty in the review process to consider the species for federal listing as threatened or endangered. Systematic survey methods, which strive for complete coverage of an area and often use broadcasts of conspecific calls, have been developed to overcome these potential biases, but no study has compared habitat characteristics around nests found opportunistically with those found systematically. We compared habitat characteristics in a 0.4-ha area around nests found systematically (n = 27) versus those found opportunistically (n = 22) on 3 national forests in eastern Oregon. We found that both density of large trees (systematic: x?? = 16.4 ?? 3.1 trees/ha; x?? ?? SE; opportunistic: x?? = 21.3 ?? 3.2; P = 0.56) and canopy closure (systematic: x?? = 72 ?? 2%; opportunistic: x?? = 70 ?? 2%; P = 0.61) were similar around nests found with either search method. Our results diminish concern that past survey methods mischaracterized northern goshawk nest-site structure. However, because northern goshawks nest in a variety of forest cover types with a wide range of structural characteristics, these results do not decrease the value of systematic survey methods in determining the most representative habitat descriptions for northern goshawks. Rigorous survey protocols allow repeatability and comparability of monitoring efforts and results over time.

Testing models of female reproductive migratory behaviour and population structure in the Caribbean hawksbill turtle, Eretmochelys imbricata, with mtDNA sequences.

PubMed

Bass, A L; Good, D A; Bjorndal, K A; Richardson, J I; Hillis, Z M; Horrocks, J A; Bowen, B W

1996-06-01

Information on the reproductive behaviour and population structure of female hawksbill turtles, Eretmochelys imbricata, is necessary to define conservation priorities for this highly endangered species. Two hypotheses to explain female nest site choice, natal homing and social facilitation, were tested by analyzing mtDNA control region sequences of 103 individuals from seven nesting colonies in the Caribbean and western Atlantic. Under the social facilitation model, newly mature females follow older females to a nesting location, and subsequently use this site for future nesting. This model generates an expectation that female lineages will be homogenized among regional nesting colonies. Contrary to expectations of the social facilitation model, mtDNA lineages were highly structured among western Atlantic nesting colonies. These analyses identified at least 6 female breeding stocks in the Caribbean and western Atlantic and support a natal homing model for recruitment of breeding females. Reproductive populations are effectively isolated over ecological time scales, and recovery plans for this species should include protection at the level of individual nesting colonies.

Increased levels of arginine vasotocin and neurophysin during nesting in sea turtles.

PubMed

Figler, R A; MacKenzie, D S; Owens, D W; Licht, P; Amoss, M S

1989-02-01

Arginine vasotocin (AVT) and neurophysin (NP) levels were measured by radioimmunoassay in two species of sea turtle, the olive ridley, Lepidochelys olivacea, and the loggerhead, Caretta caretta, during the brief period of nesting and oviposition. In both species, AVT was low in animals which were not reproductively active. AVT was also low at the time animals emerged from the surf to nest, but increased significantly during oviposition and then declined as the animals returned to the water. NP increased in concert with AVT, also reaching highest levels during oviposition. In both species, however, NP levels remained elevated over prenesting levels at the time of return to the water. These findings are consistent with the hypothesis that an AVT-neurophysin complex is released from the neurohypophysis during nesting, and that AVT is a physiological regulator of oviducal contractions in sea turtles.

Nest-site characteristics and linear abundance of cliff-nesting American kestrels on San Clemente Island, California

USGS Publications Warehouse

Sullivan, Brian L.; Kershner, Eric L.; Finn, S.P.; Condon, Anne M.; Cooper, Douglass M.; Garcelon, David K.

2003-01-01

American Kestrels( Falco sparverius) are typically secondary-cavity nesters, and use of natural cliff cavities for nest sites is less-commonly reported. On San Clemente Island (SCI), California, however, American Kestrels nest primarily on cliffs in major canyons(93%), to a lesser extent on seacliffs(4%), as well as in man-made structures (3%). We located and mapped 99 American Kestrel territories on SCI, and recorded 11 nest-site characteristics at 40 cliff nests during 2001-02. Nest cliffs were typically fractured igneous rock with mean height of 16.1 m +_ 1.8 SE. Mean slope of nest cliffs was vertical (x=91 degrees). Nest cliffs and cavities were significantly oriented to the southeast, away from the prevailing wind direction(NW). In eight canyons, where we believe that we found all occupied American Kestrel territories, the mean linear abundance was 2.1 pairs/km, greater than most published estimates. Contrary to most previous studies, no American Kestrels nested in tree cavities despite their presence in SCI canyons. The absence of cavity-excavating breeding birds from the island likely restricts kestrels to nesting in naturally-formed cavities and man-made structures.

Habitat suitability and nest survival of white-headed woodpeckers in unburned forests of Oregon

USGS Publications Warehouse

Hollenbeck, Jeff P.; Saab, Victoria A.; Frenzel, Richard W.

2011-01-01

We evaluated habitat suitability and nest survival of breeding white-headed woodpeckers (Picoides albolarvatus) in unburned forests of central Oregon, USA. Daily nest-survival rate was positively related to maximum daily temperature during the nest interval and to density of large-diameter trees surrounding the nest tree. We developed a niche-based habitat suitability model (partitioned Mahalanobis distance) for nesting white-headed woodpeckers using remotely sensed data. Along with low elevation, high density of large trees, and low slope, our habitat suitability model suggested that interspersion–juxtaposition of low- and high-canopy cover ponderosa pine (Pinus ponderosa) patches was important for nest-site suitability. Cross-validation suggested the model performed adequately for management planning at a scale >1 ha. Evaluation of mapped habitat suitability index (HSI) suggested that the maximum predictive gain (HSI = 0.36), where the number of nest locations are maximized in the smallest proportion of the modeled landscape, provided an objective initial threshold for identification of suitable habitat. However, managers can choose the threshold HSI most appropriate for their purposes (e.g., locating regions of low–moderate suitability that have potential for habitat restoration). Consequently, our habitat suitability model may be useful for managing dry coniferous forests for white-headed woodpeckers in central Oregon; however, model validation is necessary before our model could be applied to other locations.

Contaminant exposure and effects in Red-Winged Blackbirds inhabiting stormwater retention ponds

USGS Publications Warehouse

Sparling, D.W.; Eisemann, J.D.; Kuenzel, W.J.

2004-01-01

Stormwater wetlands are created to retain water from storms and snow melt to reduce sediment, nutrient, and contaminant pollution of natural waterways in metropolitan areas. However, they are often a source of attractive habitat to wetland-associated wildlife. In this study of 12 stormwater wetlands and a larger, older reference site, elevated concentrations of zinc and copper were found in sediments and carcasses of 8-day-old red-winged blackbird (Agelaius phoeniceus) nestlings inhabiting stormwater sites. Although nesting success in the stormwater wetlands was comparable to national averages, sediment zinc concentrations correlated with clutch size, hatching success, fledgling success, and Mayfield nest success, suggesting that the nestlings may have been stressed and impaired by elevated zinc. This stress may have been direct on the nestlings or indirect through effects on the availability of food organisms.

Contaminant exposure and effects in red-winged blackbirds inhabiting stormwater retention ponds.

PubMed

Sparling, Donald W; Eisemann, John D; Kuenzel, Wayne

2004-05-01

Stormwater wetlands are created to retain water from storms and snow melt to reduce sediment, nutrient, and contaminant pollution of natural waterways in metropolitan areas. However, they are often a source of attractive habitat to wetland-associated wildlife. In this study of 12 stormwater wetlands and a larger, older reference site, elevated concentrations of zinc and copper were found in sediments and carcasses of 8-day-old red-winged blackbird (Agelaius phoeniceus) nestlings inhabiting stormwater sites. Although nesting success in the stormwater wetlands was comparable to national averages, sediment zinc concentrations correlated with clutch size, hatching success, fledgling success, and Mayfield nest success, suggesting that the nestlings may have been stressed and impaired by elevated zinc. This stress may have been direct on the nestlings or indirect through effects on the availability of food organisms.

Lysophosphatidic Acid and Apolipoprotein A1 Predict Increased Risk of Developing World Trade Center Lung Injury: A Nested Case-Control Study

PubMed Central

Tsukiji, Jun; Cho, Soo Jung; Echevarria, Ghislaine C.; Kwon, Sophia; Joseph, Phillip; Schenck, Edward J.; Naveed, Bushra; Prezant, David J.; Rom, William N.; Schmidt, Ann Marie; Weiden, Michael D.; Nolan, Anna

2014-01-01

Rationale Metabolic syndrome, inflammatory and vascular injury markers measured in serum after WTC exposures predict abnormal FEV1. We hypothesized that elevated LPA levels predict FEV1

Department of Defense Natural Resources Program: Songbird Nest Boxes. Section 5.1.8., US Army Corps of Engineers Wildlife Resources Management Manual

DTIC Science & Technology

1988-11-01

SUBJECT TERMS (Continue on reverse if necessary and idenify by block number) FIELD GROUP SUB-GROUP Artificial nesting structures Songbord management...5.1.8 in Chapter 5 -- MANAGEMENT PRACTICES AND TECHNIQUES , Part 5.1 -- NESTING AND ROOSTING STRUCTURES, of the US ARMY CORPS OF ENGINEERS WILDLIFE...natural cavities has become a widely used management technique . Nest box programs have played an important role in the restoration of species such as

Abundance and rates of brood parasitism by brown-headed cowbirds over an elevational gradient in the southern Sierra Nevada

Treesearch

Kathryn Purcell; Jared Verner

1999-01-01

We studied Brown-headed Cowbird (Molothrus ater) parasitism rates in four forest types (ponderosa pine, mixed conifer, true fir, and lodgepole pine) over an elevational gradient in the southern Sierra Nevada. Cowbirds were most abundant and parasitism rates were highest at the lowest sites. All but one of 17 parasitized nests were found in the...

Management of western coniferous forest habitat for nesting accipiter hawks

Treesearch

Richard T. Reynolds

1983-01-01

Availability of nesting sites can limit accipiter populations. Because accipiters nest in dense forest stands, any alteration that opens these stands is likely to lessen their desirability as nest sites. Tree growth and the associated changes in the vegetative structure of aging nest sites limit the number of years sites will be suitable. Therefore, prospective...

Ultra-Fine Scale Spatially-Integrated Mapping of Habitat and Occupancy Using Structure-From-Motion

PubMed Central

McDowall, Philip; Lynch, Heather J.

2017-01-01

Organisms respond to and often simultaneously modify their environment. While these interactions are apparent at the landscape extent, the driving mechanisms often occur at very fine spatial scales. Structure-from-Motion (SfM), a computer vision technique, allows the simultaneous mapping of organisms and fine scale habitat, and will greatly improve our understanding of habitat suitability, ecophysiology, and the bi-directional relationship between geomorphology and habitat use. SfM can be used to create high-resolution (centimeter-scale) three-dimensional (3D) habitat models at low cost. These models can capture the abiotic conditions formed by terrain and simultaneously record the position of individual organisms within that terrain. While coloniality is common in seabird species, we have a poor understanding of the extent to which dense breeding aggregations are driven by fine-scale active aggregation or limited suitable habitat. We demonstrate the use of SfM for fine-scale habitat suitability by reconstructing the locations of nests in a gentoo penguin colony and fitting models that explicitly account for conspecific attraction. The resulting digital elevation models (DEMs) are used as covariates in an inhomogeneous hybrid point process model. We find that gentoo penguin nest site selection is a function of the topography of the landscape, but that nests are far more aggregated than would be expected based on terrain alone, suggesting a strong role of behavioral aggregation in driving coloniality in this species. This integrated mapping of organisms and fine scale habitat will greatly improve our understanding of fine-scale habitat suitability, ecophysiology, and the complex bi-directional relationship between geomorphology and habitat use. PMID:28076351

Management of livestock to improve and maintain prairie chicken habitat on the Sheyenne National Grasslands

Treesearch

Robert L. Eng; John E. Toepfer; Jay A. Newell

1988-01-01

Cover requirements of prairie grouse are primarily related to vegetative structure, whereas food needs are species related. Seasonal distribution and intensity of grazing initially alter the structure and ultimately can alter species composition. Initial successful nests were found in areas of more and higher residual cover than unsuccessful nests. Nesting areas were...

Nested PCR Biases in Interpreting Microbial Community Structure in 16S rRNA Gene Sequence Datasets

PubMed Central

Yu, Guoqin; Fadrosh, Doug; Goedert, James J.; Ravel, Jacques; Goldstein, Alisa M.

2015-01-01

Background Sequencing of the PCR-amplified 16S rRNA gene has become a common approach to microbial community investigations in the fields of human health and environmental sciences. This approach, however, is difficult when the amount of DNA is too low to be amplified by standard PCR. Nested PCR can be employed as it can amplify samples with DNA concentration several-fold lower than standard PCR. However, potential biases with nested PCRs that could affect measurement of community structure have received little attention. Results In this study, we used 17 DNAs extracted from vaginal swabs and 12 DNAs extracted from stool samples to study the influence of nested PCR amplification of the 16S rRNA gene on the estimation of microbial community structure using Illumina MiSeq sequencing. Nested and standard PCR methods were compared on alpha- and beta-diversity metrics and relative abundances of bacterial genera. The effects of number of cycles in the first round of PCR (10 vs. 20) and microbial diversity (relatively low in vagina vs. high in stool) were also investigated. Vaginal swab samples showed no significant difference in alpha diversity or community structure between nested PCR and standard PCR (one round of 40 cycles). Stool samples showed significant differences in alpha diversity (except Shannon’s index) and relative abundance of 13 genera between nested PCR with 20 cycles in the first round and standard PCR (P<0.01), but not between nested PCR with 10 cycles in the first round and standard PCR. Operational taxonomic units (OTUs) that had low relative abundance (sum of relative abundance <0.167) accounted for most of the distortion (>27% of total OTUs in stool). Conclusions Nested PCR introduced bias in estimated diversity and community structure. The bias was more significant for communities with relatively higher diversity and when more cycles were applied in the first round of PCR. We conclude that nested PCR could be used when standard PCR does not work. However, rare taxa detected by nested PCR should be validated by other technologies. PMID:26196512

Nested PCR Biases in Interpreting Microbial Community Structure in 16S rRNA Gene Sequence Datasets.

PubMed

Yu, Guoqin; Fadrosh, Doug; Goedert, James J; Ravel, Jacques; Goldstein, Alisa M

2015-01-01

Sequencing of the PCR-amplified 16S rRNA gene has become a common approach to microbial community investigations in the fields of human health and environmental sciences. This approach, however, is difficult when the amount of DNA is too low to be amplified by standard PCR. Nested PCR can be employed as it can amplify samples with DNA concentration several-fold lower than standard PCR. However, potential biases with nested PCRs that could affect measurement of community structure have received little attention. In this study, we used 17 DNAs extracted from vaginal swabs and 12 DNAs extracted from stool samples to study the influence of nested PCR amplification of the 16S rRNA gene on the estimation of microbial community structure using Illumina MiSeq sequencing. Nested and standard PCR methods were compared on alpha- and beta-diversity metrics and relative abundances of bacterial genera. The effects of number of cycles in the first round of PCR (10 vs. 20) and microbial diversity (relatively low in vagina vs. high in stool) were also investigated. Vaginal swab samples showed no significant difference in alpha diversity or community structure between nested PCR and standard PCR (one round of 40 cycles). Stool samples showed significant differences in alpha diversity (except Shannon's index) and relative abundance of 13 genera between nested PCR with 20 cycles in the first round and standard PCR (P<0.01), but not between nested PCR with 10 cycles in the first round and standard PCR. Operational taxonomic units (OTUs) that had low relative abundance (sum of relative abundance <0.167) accounted for most of the distortion (>27% of total OTUs in stool). Nested PCR introduced bias in estimated diversity and community structure. The bias was more significant for communities with relatively higher diversity and when more cycles were applied in the first round of PCR. We conclude that nested PCR could be used when standard PCR does not work. However, rare taxa detected by nested PCR should be validated by other technologies.

Integrating spatial data and shorebird nesting locations to predict the potential future impact of global warming on coastal habitats: A case study on Farasan Islands, Saudi Arabia.

PubMed

Alrashidi, Monif; Shobrak, Mohammed; Al-Eissa, Mohammed S; Székely, Tamás

2012-07-01

One of the expected effects of the global warming is changing coastal habitats by accelerating the rate of sea level rise. Coastal habitats support large number of marine and wetland species including shorebirds (plovers, sandpipers and allies). In this study, we investigate how coastal habitats may be impacted by sea level rise in the Farasan Islands, Kingdom of Saudi Arabia. We use Kentish plover Charadrius alexandrinus - a common coastal breeding shorebird - as an ecological model species to predict the influence of sea level rise. We found that any rise of sea level is likely to inundate 11% of Kentish plover nests. In addition, 5% of the coastal areas of Farasan Islands, which support 26% of Kentish plover nests, will be flooded, if sea level rises by one metre. Our results are constrained by the availability of data on both elevation and bird populations. Therefore, we recommend follow-up studies to model the impacts of sea level rise using different elevation scenarios, and the establishment of a monitoring programme for breeding shorebirds and seabirds in Farasan Islands to assess the impact of climate change on their populations.

[Effect of landscape change on the structure of the sting-less bee community (Hymenoptera: Apidae) in Meta, Colombia].

PubMed

Nates-Parra, Guiomar; Palacios, Eliana; Parra-H, Alejandro

2008-09-01

Stingless bees represent one of the most diversified components of the natural Apoidea fauna of pollinators in the tropics. They use diverse kinds of substrates and inhabit varied habitats. Some species are typical for some natural either artificial place. The landscape alteration were this group of bees nests, has and important impact on the natural composition of its community structure, fact which is reflected in the nest density. We analyzed the structure composition of the stingless bees' community in three environments in the Colombian Ilanos piedmont, an important region that represents the transition between Andean ecosystems and a savannah that is seriously threatened by cattle practices. We made systematic samples in secondary forest, agro-ecosystems and urban areas, recording the presence of 204 nests from 11 genera (24 species). The nest density per landscape was heterogeneous and never higher than 16 nests/Ha. We observed two nesting patterns and an effect of sampling criterion on the measured biodiversity.

Age-specific productivity and nest site characteristics of Cooper's hawks (Accipiter cooperii)

USGS Publications Warehouse

Moore, K.R.; Henny, C.J.

1984-01-01

Nesting Cooper's Hawks (Accipiter cooperii) were studied in northeastern Oregon. Second-year (SY) males did not breed, but 22 percent of the breeding females were SY's. Mean clutch size (P = 0.012) and mean number of young fledged per pair that laid eggs (P < 0.10) were lower for SY females than for adult (after second year [ASY}) females; however, an equal percentage of the eggs (excluding a collected sample egg) yielded fledged young for each age class. Stepwise discriminant analysis suggested differences in structural characteristics of the nest site habitat for ASY and SY females, i.e., SY female nest sites were associated with younger successional stages than ASY female nest sites. Nests of both age groups were built in trees with high crown volume, but ASY females utilized mistletoe (Arceuthobium sp.) for nest structures more frequently (P < 0.01) than SY females.

Community-level demographic consequences of urbanization: an ecological network approach.

PubMed

Rodewald, Amanda D; Rohr, Rudolf P; Fortuna, Miguel A; Bascompte, Jordi

2014-11-01

Ecological networks are known to influence ecosystem attributes, but we poorly understand how interspecific network structure affect population demography of multiple species, particularly for vertebrates. Establishing the link between network structure and demography is at the crux of being able to use networks to understand population dynamics and to inform conservation. We addressed the critical but unanswered question, does network structure explain demographic consequences of urbanization? We studied 141 ecological networks representing interactions between plants and nesting birds in forests across an urbanization gradient in Ohio, USA, from 2001 to 2011. Nest predators were identified by video-recording nests and surveyed from 2004 to 2011. As landscapes urbanized, bird-plant networks were more nested, less compartmentalized and dominated by strong interactions between a few species (i.e. low evenness). Evenness of interaction strengths promoted avian nest survival, and evenness explained demography better than urbanization, level of invasion, numbers of predators or other qualitative network metrics. Highly uneven networks had approximately half the nesting success as the most even networks. Thus, nest survival reflected how urbanization altered species interactions, particularly with respect to how nest placement affected search efficiency of predators. The demographic effects of urbanization were not direct, but were filtered through bird-plant networks. This study illustrates how network structure can influence demography at the community level and further, that knowledge of species interactions and a network approach may be requisite to understanding demographic responses to environmental change. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Oviduct modifications in foam-nesting frogs, with emphasis on the genus Leptodactylus (Amphibia, Leptodactylidae)

USGS Publications Warehouse

Furness, Andrew I.; McDiarmid, Roy W.; Heyer, W. Ronald; Zug, George R.

2010-01-01

Various species of frogs produce foam nests that hold their eggs during development. We examined the external morphology and histology of structures associated with foam nest production in frogs of the genus Leptodactylus and a few other taxa. We found that the posterior convolutions of the oviducts in all mature female foam-nesting frogs that we examined were enlarged and compressed into globular structures. This organ-like portion of the oviduct has been called a "foam gland" and these structures almost certainly produce the secretion that is beaten by rhythmic limb movements into foam that forms the nest. However, the label "foam gland" is a misnomer because the structures are simply enlarged and tightly folded regions of the pars convoluta of the oviduct, rather than a separate structure; we suggest the name pars convoluta dilata (PCD) for this feature. Although all the foam-nesters we examined had a pars convoluta dilata, its size and shape showed considerable interspecific variation. Some of this variation likely reflects differences in the breeding behaviors among species and in the size, type, and placement of their foam nests. Other variation, particularly in size, may be associated with the physiological periodicity and reproductive state of the female, her age, and/or the number of times she has laid eggs.

Nesting Ecology of Hawksbill Sea Turtles (Eretmochelys imbricata) on Utila, Honduras

NASA Astrophysics Data System (ADS)

Damazo, Lindsey Renee Eggers

The hawksbill sea turtle (Eretmochelys imbricata) has a circumtropical distribution and plays an important role in maintaining the health of coral reefs. Unfortunately, hawksbill populations have been decimated, and estimated numbers in the Caribbean are less than 10% of populations a century ago. The hawksbill is considered Critically Endangered, and researchers are coordinating worldwide efforts to protect this species. One country where we lack knowledge regarding hawksbills is Honduras. This study aimed to increase our understanding of hawksbill nesting ecology in Caribbean Honduras. Characteristics of hawksbill nesting activity and a nesting beach on the island of Utila were elucidated using satellite telemetry, beach profiling, vegetation surveys, beach monitoring, and nest temperature profiles. We affixed satellite transmitters to two nesting hawksbills, and found the turtles migrated to different countries. One turtle traveled 403 km to a bay in Mexico, and the other traveled 181 km to a Marine Protected Area off Belize. This study presents the first description of hawksbill migration routes from Honduras, facilitating protection efforts for turtles that traverse international waters. To investigate nesting beach and turtle characteristics, we conducted beach monitoring during the 2012 nesting season. Nesting turtle carapace sizes were similar to worldwide values, but hatchlings were heavier. To measure nest temperatures, we placed thermocouple data loggers in four nests and four pseudo-nests. Data suggested metabolic heating may be maintaining nest temperatures above the pivotal temperature. However, large temperature fluctuations corresponding to rainfall from Hurricane Ernesto (as determined using a time series cross-correlation analysis) make it difficult to predict sex ratios, and underscore the impact stochastic events can have on nest temperatures. We created topographic and substrate profiles of the beach, and found it was 475 m long, yet hawksbills preferentially nested along 80 m that differed from the remainder of the beach in having higher elevation and extensive forest cover. This is the first study from Honduras to report a regular nesting population of hawksbills as well as characterize a nesting beach for this species. It provides an important foundation for hawksbill research in Honduras, a region where we have insufficient knowledge to adequately protect this critically endangered species.

Juvenile hormone levels reflect social opportunities in the facultatively eusocial sweat bee Megalopta genalis (Hymenoptera: Halictidae).

PubMed

Smith, Adam R; Kapheim, Karen M; Pérez-Ortega, Betzi; Brent, Colin S; Wcislo, William T

2013-01-01

The evolution of eusociality is hypothesized to have involved de-coupling parental care from reproduction mediated by changes in endocrine regulation. While data for obligately eusocial insects are consistent with this hypothesis, we lack information from species representative of the transition from solitary reproduction to eusociality. Here we report the first evidence for a link between endocrine processes and social behavior in a facultatively eusocial bee, Megalopta genalis (Halictidae). Using females that varied in social, reproductive, and ecological context, we measured juvenile hormone (JH), a major regulator of colony caste dynamics in other eusocial species. JH was low at adult emergence, but elevated after 10 days in all nesting females. Females reared in cages with ad lib nutrition, however, did not elevate JH levels after 10 days. All reproductive females had significantly more JH than all age-matched non-reproductive females, suggesting a gonadotropic function. Among females in established nests, JH was higher in queens than workers and solitary reproductives, suggesting a role for JH in social dominance. A lack of significant differences in JH between solitary reproductives and non-reproductive workers suggests that JH content reflects more than reproductive status. Our data support the hypothesis that endocrine modifications are involved in the evolutionary decoupling of reproductive and somatic effort in social insects. These are the first measurements of JH in a solitary-nesting hymenopteran, and the first to compare eusocial and solitary nesting individuals of the same species. Published by Elsevier Inc.

Oh sister, where art thou? Spatial population structure and the evolution of an altruistic defence trait.

PubMed

Pamminger, T; Foitzik, S; Metzler, D; Pennings, P S

2014-11-01

The evolution of parasite virulence and host defences is affected by population structure. This effect has been confirmed in studies focusing on large spatial scales, whereas the importance of local structure is not well understood. Slavemaking ants are social parasites that exploit workers of another species to rear their offspring. Enslaved workers of the host species Temnothorax longispinosus have been found to exhibit an effective post-enslavement defence behaviour: enslaved workers were observed killing a large proportion of the parasites' offspring. As enslaved workers do not reproduce, they gain no direct fitness benefit from this 'rebellion' behaviour. However, there may be an indirect benefit: neighbouring host nests that are related to 'rebel' nests can benefit from a reduced raiding pressure, as a result of the reduction in parasite nest size due to the enslaved workers' killing behaviour. We use a simple mathematical model to examine whether the small-scale population structure of the host species could explain the evolution of this potentially altruistic defence trait against slavemaking ants. We find that this is the case if enslaved host workers are related to nearby host nests. In a population genetic study, we confirm that enslaved workers are, indeed, more closely related to host nests within the raiding range of their resident slavemaker nest, than to host nests outside the raiding range. This small-scale population structure seems to be a result of polydomy (e.g. the occupation of several nests in close proximity by a single colony) and could have enabled the evolution of 'rebellion' by kin selection. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Relationships of surrounding riparian habitat to nest-box use and reproductive outcome in House Wrens

Treesearch

Deborah M. Finch

1989-01-01

I assessed relationships among habitat structure, nest-site selection, and reproductive outcome of House Wrens (Troglodytes aedon) by establishing three nest-box grids in riparian woodlands in southeastern Wyoming. Over a 3-year period, 37% of the boxes contained House Wren nests; 20% contained unused nests built by male House Wrens; and 42% were never used by wrens....

Embryonic mortality and abnormalities of aquatic birds: Apparent impacts of selenium from irrigation drainwater

USGS Publications Warehouse

Ohlendorf, H.M.; Hoffman, D.J.; Saiki, M.K.; Aldrich, T.W.

1986-01-01

Severe reproductive impacts were found in aquatic birds nesting on irrigation drainwater ponds in the San Joaquin Valley of California. Of 347 nests studied to late incubation or to hatching, 40.6% had at least one dead embryo and 19.6% had at least one embryo or chick with an obvious external anomaly. The deformities were often multiple and included missing or abnormal eyes, beaks, wings, legs and feet. Brain, heart, liver and skeletal anomalies were also present. Mean selenium concentrations in plants, invertebrates, and fish from the ponds were 22?175 ppm (dry weight), about 12 to 130 times those found at a nearby control area. Bird eggs (2.2?110 ppm) and livers (19?130 ppm) also contained elevated levels of selenium. Aquatic birds may experience similar problems in other areas where selenium occurs at elevated levels.

Predator behaviour and predation risk in the heterogeneous Arctic environment.

PubMed

Lecomte, Nicolas; Careau, Vincent; Gauthier, Gilles; Giroux, Jean-François

2008-05-01

1. Habitat heterogeneity and predator behaviour can strongly affect predator-prey interactions but these factors are rarely considered simultaneously, especially when systems encompass multiple predators and prey. 2. In the Arctic, greater snow geese Anser caerulescens atlanticus L. nest in two structurally different habitats: wetlands that form intricate networks of water channels, and mesic tundra where such obstacles are absent. In this heterogeneous environment, goose eggs are exposed to two types of predators: the arctic fox Vulpes lagopus L. and a diversity of avian predators. We hypothesized that, contrary to birds, the hunting ability of foxes would be impaired by the structurally complex wetland habitat, resulting in a lower predation risk for goose eggs. 3. In addition, lemmings, the main prey of foxes, show strong population cycles. We thus further examined how their fluctuations influenced the interaction between habitat heterogeneity and fox predation on goose eggs. 4. An experimental approach with artificial nests suggested that foxes were faster than avian predators to find unattended goose nests in mesic tundra whereas the reverse was true in wetlands. Foxes spent 3.5 times more time between consecutive attacks on real goose nests in wetlands than in mesic tundra. Their attacks on goose nests were also half as successful in wetlands than in mesic tundra whereas no difference was found for avian predators. 5. Nesting success in wetlands (65%) was higher than in mesic tundra (56%) but the difference between habitats increased during lemming crashes (15%) compared to other phases of the cycle (5%). Nests located at the edge of wetland patches were also less successful than central ones, suggesting a gradient in accessibility of goose nests in wetlands for foxes. 6. Our study shows that the structural complexity of wetlands decreases predation risk from foxes but not avian predators in arctic-nesting birds. Our results also demonstrate that cyclic lemming populations indirectly alter the spatial distribution of productive nests due to a complex interaction between habitat structure, prey-switching and foraging success of foxes.

Does habitat fragmentation influence nest predation in the shortgrass prairie?

USGS Publications Warehouse

Howard, M.N.; Skagen, S.K.; Kennedy, P.L.

2001-01-01

We examined the effects of habitat fragmentation and vegetation structure of shortgrass prairie and Conservation Reserve Program (CRP) lands on predation rates of artificial and natural nests in northeastern Colorado. The CRP provides federal payments to landowners to take highly erodible cropland out of agricultural production. In our study area, CRP lands have been reseeded primarily with non-native grasses, and this vegetation is taller than native shortgrass prairie. We measured three indices of habitat fragmentation (patch size, degree of matrix fragmentation, and distance from edge), none of which influenced mortality rates of artificial or natural nests. Vegetation structure did influence predation rates of artificial nests; daily mortality decreased significantly with increasing vegetation height. Vegetation structure did not influence predation rates of natural nests. CRP lands and shortgrass sites did not differ with respect to mortality rates of artificial nests. Our study area is only moderately fragmented; 62% of the study area is occupied by native grassland. We conclude that the extent of habitat fragmentation in our study area does not result in increased predation in remaining patches of shortgrass prairie habitat.

Cavity Nesting Birds

Treesearch

Virgil E. Scott; Keith E. Evans; David R. Patton; Charles P. Stone

1977-01-01

Many species of cavity-nesting birds have declined because of habitat reduction. In the eastern United States, where primeval forests are gone, purple martins depend almost entirely on man-made nesting structures (Allen and Nice 1952). The hole-nesting population of peregrine falcons disappeared with the felling of the giant trees upon which they depended (Hickey and...

Selection indicates preference in diverse habitats: A Ground-Nesting bird (charadrius melodus) using reservoir shoreline

USGS Publications Warehouse

Anteau, M.J.; Sherfy, M.H.; Wiltermuth, M.T.

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006-2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m 2) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies.

Selection indicates preference in diverse habitats: A ground-nesting bird (Charadrius melodus) using reservoir shoreline

USGS Publications Warehouse

Anteau, Michael J.; Sherfy, Mark H.; Wiltermuth, Mark T.

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006–2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m2) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies.

Selection indicates preference in diverse habitats: a ground-nesting bird (Charadrius melodus) using reservoir shoreline.

PubMed

Anteau, Michael J; Sherfy, Mark H; Wiltermuth, Mark T

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006-2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m(2)) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies.

Selection Indicates Preference in Diverse Habitats: A Ground-Nesting Bird (Charadrius melodus) Using Reservoir Shoreline

PubMed Central

Anteau, Michael J.; Sherfy, Mark H.; Wiltermuth, Mark T.

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006–2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m2) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies. PMID:22299037

Nest suitability, fine-scale population structure and male-mediated dispersal of a solitary ground nesting bee in an urban landscape.

PubMed

López-Uribe, Margarita M; Morreale, Stephen J; Santiago, Christine K; Danforth, Bryan N

2015-01-01

Bees are the primary pollinators of flowering plants in almost all ecosystems. Worldwide declines in bee populations have raised awareness about the importance of their ecological role in maintaining ecosystem functioning. The naturally strong philopatric behavior that some bee species show can be detrimental to population viability through increased probability of inbreeding. Furthermore, bee populations found in human-altered landscapes, such as urban areas, can experience lower levels of gene flow and effective population sizes, increasing potential for inbreeding depression in wild bee populations. In this study, we investigated the fine-scale population structure of the solitary bee Colletes inaequalis in an urbanized landscape. First, we developed a predictive spatial model to detect suitable nesting habitat for this ground nesting bee and to inform our field search for nests. We genotyped 18 microsatellites in 548 female individuals collected from nest aggregations throughout the study area. Genetic relatedness estimates revealed that genetic similarity among individuals was slightly greater within nest aggregations than among randomly chosen individuals. However, genetic structure among nest aggregations was low (Nei's GST = 0.011). Reconstruction of parental genotypes revealed greater genetic relatedness among females than among males within nest aggregations, suggesting male-mediated dispersal as a potentially important mechanism of population connectivity and inbreeding avoidance. Size of nesting patch was positively correlated with effective population size, but not with other estimators of genetic diversity. We detected a positive trend between geographic distance and genetic differentiation between nest aggregations. Our landscape genetic models suggest that increased urbanization is likely associated with higher levels of inbreeding. Overall, these findings emphasize the importance of density and distribution of suitable nesting patches for enhancing bee population abundance and connectivity in human dominated habitats and highlights the critical contribution of landscape genetic studies for enhanced conservation and management of native pollinators.

Nest Suitability, Fine-Scale Population Structure and Male-Mediated Dispersal of a Solitary Ground Nesting Bee in an Urban Landscape

PubMed Central

López-Uribe, Margarita M.; Morreale, Stephen J.; Santiago, Christine K.; Danforth, Bryan N.

2015-01-01

Bees are the primary pollinators of flowering plants in almost all ecosystems. Worldwide declines in bee populations have raised awareness about the importance of their ecological role in maintaining ecosystem functioning. The naturally strong philopatric behavior that some bee species show can be detrimental to population viability through increased probability of inbreeding. Furthermore, bee populations found in human-altered landscapes, such as urban areas, can experience lower levels of gene flow and effective population sizes, increasing potential for inbreeding depression in wild bee populations. In this study, we investigated the fine-scale population structure of the solitary bee Colletes inaequalis in an urbanized landscape. First, we developed a predictive spatial model to detect suitable nesting habitat for this ground nesting bee and to inform our field search for nests. We genotyped 18 microsatellites in 548 female individuals collected from nest aggregations throughout the study area. Genetic relatedness estimates revealed that genetic similarity among individuals was slightly greater within nest aggregations than among randomly chosen individuals. However, genetic structure among nest aggregations was low (Nei’s GST = 0.011). Reconstruction of parental genotypes revealed greater genetic relatedness among females than among males within nest aggregations, suggesting male-mediated dispersal as a potentially important mechanism of population connectivity and inbreeding avoidance. Size of nesting patch was positively correlated with effective population size, but not with other estimators of genetic diversity. We detected a positive trend between geographic distance and genetic differentiation between nest aggregations. Our landscape genetic models suggest that increased urbanization is likely associated with higher levels of inbreeding. Overall, these findings emphasize the importance of density and distribution of suitable nesting patches for enhancing bee population abundance and connectivity in human dominated habitats and highlights the critical contribution of landscape genetic studies for enhanced conservation and management of native pollinators. PMID:25950429

Nest predation risk explains variation in avian clutch size

USGS Publications Warehouse

Dillon, Kristen G.; Conway, Courtney J.

2018-01-01

Questions about the ecological drivers of, and mechanistic constraints on, productivity have driven research on life-history evolution for decades. Resource availability and offspring mortality are considered among the 2 most important influences on the number of offspring per reproductive attempt. We used a factorial experimental design to manipulate food abundance and perceived offspring predation risk in a wild avian population (red-faced warblers; Cardellina rubrifrons) to identify the mechanistic cause of variation in avian clutch size. Additionally, we tested whether female quality helped explain the extant variation in clutch size. We found no support for the Food Limitation or Female Quality Hypotheses, but we did find support for both predictions of the Nest Predation Risk Hypothesis. Females that experienced an experimentally heightened perception of offspring predation risk responded by laying a smaller clutch than females in the control group. Additionally, predation rates at artificial nests were highest where red-faced warbler clutch size was smallest (at high elevations). Life-history theory predicts that an individual should invest less in reproduction when high nest predation risk reduces the likely benefit from that nesting attempt and, indeed, we found that birds exhibit phenotypic plasticity in clutch size by laying fewer eggs in response to increasing nest predation risk.

Migratory patterns and population structure among breeding and wintering red-breasted mergansers (Mergus serrator) and common mergansers (M. merganser)

USGS Publications Warehouse

Pearce, J.M.; McCracken, K.G.; Christensen, Thomas K.; Zhuravlev, Y.N.

2009-01-01

Philopatry has long been assumed to structure populations of waterfowl and other species of birds genetically, especially via maternally transmitted mitochondrial DNA (mtDNA), yet other migratory behaviors and nesting ecology (use of ground vs. cavity sites) may also contribute to population genetic structure. We investigated the effects of migration and nesting ecology on the population genetic structure of two Holarctic waterfowl, the Red-breasted Merganser (Mergus serrator) and Common Merganser (M. merganser), using mtDNA control-region sequence data. Red-breasted Mergansers (a ground-nesting species) exhibited lower levels of population differentiation across their North American range, possibly as a result of post-Pleistocene range expansion and population growth. By contrast, Common Mergansers (a cavity-nesting species) breeding in western and eastern North America were strongly differentiated, as were continental groups in North America and Europe. Our hypothesis that population differentiation of breeding female Common Mergansers results from limited migration during non-breeding periods was not supported, in that equally heterogeneous mtDNA lineages were observed in males and females on several wintering areas. The interspecific differences in mtDNA patterns for these two closely related species may have resulted from factors related to nesting ecology (ground vs. cavity nesting) and responses to historical climate change.

Biomimetic Ant-Nest Electrode Structures for High Sulfur Ratio Lithium–Sulfur Batteries

DOE PAGES

Ai, Guo; Dai, Yiling; Mao, Wenfeng; ...

2016-08-08

The lithium–sulfur (Li–S) rechargeable battery has the benefit of high gravimetric energy density and low cost. Significant research currently focuses on increasing the sulfur loading and sulfur/inactive-materials ratio, to improve life and capacity. Inspired by nature’s ant-nest structure, this study results in a novel Li–S electrode that is designed to meet both goals. With only three simple manufacturing-friendly steps, which include slurry ball-milling, doctor-blade-based laminate casting, and the use of the sacrificial method with water to dissolve away table salt, the ant-nest design has been successfully recreated in an Li–S electrode. The efficient capabilities of the ant-nest structure are adoptedmore » to facilitate fast ion transportation, sustain polysulfide dissolution, and assist efficient precipitation. Finally, high cycling stability in the Li–S batteries, for practical applications, has been achieved with up to 3 mg·cm –2 sulfur loading. Li–S electrodes with up to a 85% sulfur ratio have also been achieved for the efficient design of this novel ant-nest structure.« less

Bird nesting and droppings control on highway structures.

DOT National Transportation Integrated Search

2010-10-01

This report provides a comprehensive literature survey of permanent and temporary deterrents to nesting and roosting, a : discussion of risks to human health and safety from exposure to bird nests and droppings and recommended protective measures, : ...

Habitat structure mediates predation risk for sedentary prey: Experimental tests of alternative hypotheses

USGS Publications Warehouse

Chalfoun, A.D.; Martin, T.E.

2009-01-01

Predation is an important and ubiquitous selective force that can shape habitat preferences of prey species, but tests of alternative mechanistic hypotheses of habitat influences on predation risk are lacking. 2. We studied predation risk at nest sites of a passerine bird and tested two hypotheses based on theories of predator foraging behaviour. The total-foliage hypothesis predicts that predation will decline in areas of greater overall vegetation density by impeding cues for detection by predators. The potential-prey-site hypothesis predicts that predation decreases where predators must search more unoccupied potential nest sites. 3. Both observational data and results from a habitat manipulation provided clear support for the potential-prey-site hypothesis and rejection of the total-foliage hypothesis. Birds chose nest patches containing both greater total foliage and potential nest site density (which were correlated in their abundance) than at random sites, yet only potential nest site density significantly influenced nest predation risk. 4. Our results therefore provided a clear and rare example of adaptive nest site selection that would have been missed had structural complexity or total vegetation density been considered alone. 5. Our results also demonstrated that interactions between predator foraging success and habitat structure can be more complex than simple impedance or occlusion by vegetation. ?? 2008 British Ecological Society.

Climate correlates of 20 years of trophic changes in a high-elevation riparian system

USGS Publications Warehouse

Martin, T.E.

2007-01-01

The consequences of climate change for ecosystem structure and function remain largely unknown. Here, I examine the ability of climate variation to explain long-term changes in bird and plant populations, as well as trophic interactions in a high-elevation riparian system in central Arizona, USA, based on 20 years of study. Abundances of dominant deciduous trees have declined dramatically over the 20 years, correlated with a decline in overwinter snowfall. Snowfall can affect overwinter presence of elk, whose browsing can significantly impact deciduous tree abundance. Thus, climate may affect the plant community indirectly through effects on herbivores, but may also act directly by influencing water availability for plants. Seven species of birds were found to initiate earlier breeding associated with an increase in spring temperature across years. The advance in breeding time did not affect starvation of young or clutch size. Earlier breeding also did not increase the length of the breeding season for single-brooded species, but did for multi-brooded species. Yet, none of these phenology-related changes was associated with bird population trends. Climate had much larger consequences for these seven bird species by affecting trophic levels below (plants) and above (predators) the birds. In particular, the climate-related declines in deciduous vegetation led to decreased abundance of preferred bird habitat and increased nest predation rates. In addition, summer precipitation declined over time, and drier summers also were further associated with greater nest predation in all species. The net result was local extinction and severe population declines in some previously common bird species, whereas one species increased strongly in abundance, and two species did not show clear population changes. These data indicate that climate can alter ecosystem structure and function through complex pathways that include direct and indirect effects on abundances and interactions of multiple trophic components. ?? 2007 by the Ecological Society of America.

Climate correlates of 20 years of trophic changes in a high-elevation riparian system.

PubMed

Martin, Thomas E

2007-02-01

The consequences of climate change for ecosystem structure and function remain largely unknown. Here, I examine the ability of climate variation to explain long-term changes in bird and plant populations, as well as trophic interactions in a high-elevation riparian system in central Arizona, USA, based on 20 years of study. Abundances of dominant deciduous trees have declined dramatically over the 20 years, correlated with a decline in overwinter snowfall. Snowfall can affect overwinter presence of elk, whose browsing can significantly impact deciduous tree abundance. Thus, climate may affect the plant community indirectly through effects on herbivores, but may also act directly by influencing water availability for plants. Seven species of birds were found to initiate earlier breeding associated with an increase in spring temperature across years. The advance in breeding time did not affect starvation of young or clutch size. Earlier breeding also did not increase the length of the breeding season for single-brooded species, but did for multi-brooded species. Yet, none of these phenology-related changes was associated with bird population trends. Climate had much larger consequences for these seven bird species by affecting trophic levels below (plants) and above (predators) the birds. In particular, the climate-related declines in deciduous vegetation led to decreased abundance of preferred bird habitat and increased nest predation rates. In addition, summer precipitation declined over time, and drier summers also were further associated with greater nest predation in all species. The net result was local extinction and severe population declines in some previously common bird species, whereas one species increased strongly in abundance, and two species did not show clear population changes. These data indicate that climate can alter ecosystem structure and function through complex pathways that include direct and indirect effects on abundances and interactions of multiple trophic components.

Communal nesting under climate change: fitness consequences of higher incubation temperatures for a nocturnal lizard.

PubMed

Dayananda, Buddhi; Gray, Sarah; Pike, David; Webb, Jonathan K

2016-07-01

Communal nesting lizards may be vulnerable to climate warming, particularly if air temperatures regulate nest temperatures. In southeastern Australia, velvet geckos Oedura lesueurii lay eggs communally inside rock crevices. We investigated whether increases in air temperatures could elevate nest temperatures, and if so, how this could influence hatching phenotypes, survival, and population dynamics. In natural nests, maximum daily air temperature influenced mean and maximum daily nest temperatures, implying that nest temperatures will increase under climate warming. To determine whether hotter nests influence hatchling phenotypes, we incubated eggs under two fluctuating temperature regimes to mimic current 'cold' nests (mean = 23.2 °C, range 10-33 °C) and future 'hot' nests (27.0 °C, 14-37 °C). 'Hot' incubation temperatures produced smaller hatchlings than did cold temperature incubation. We released individually marked hatchlings into the wild in 2014 and 2015, and monitored their survival over 10 months. In 2014 and 2015, hot-incubated hatchlings had higher annual mortality (99%, 97%) than cold-incubated (11%, 58%) or wild-born hatchlings (78%, 22%). To determine future trajectories of velvet gecko populations under climate warming, we ran population viability analyses in Vortex and varied annual rates of hatchling mortality within the range 78- 96%. Hatchling mortality strongly influenced the probability of extinction and the mean time to extinction. When hatchling mortality was >86%, populations had a higher probability of extinction (PE: range 0.52- 1.0) with mean times to extinction of 18-44 years. Whether future changes in hatchling survival translate into reduced population viability will depend on the ability of females to modify their nest-site choices. Over the period 1992-2015, females used the same communal nests annually, suggesting that there may be little plasticity in maternal nest-site selection. The impacts of climate change may therefore be especially severe on communal nesting species, particularly if such species occupy thermally challenging environments. © 2016 John Wiley & Sons Ltd.

Factors influencing depredation of artificial duck nests

USGS Publications Warehouse

Esler, Daniel N.; Grand, James B.

1993-01-01

Because artificial nests can facilitate controlled experiments of nest success, we used them to assess whether human visitation, nest density, vegetation structure, and proximity to habitat edge could affect depredation of duck nests on Yukon Flats National Wildlife Refuge, Alaska. More (P < 0.01) nests in a plot visited daily (100%) were depredated than those in plots visited at intervals of 7 (40%), 14 (35%), or 28 days (45%). More (P < 0.01) nests were depredated in a plot with 10 nests/ha (95%) than nests in a plot of a lower density (2/ha; 40%). Vegetation height, vegetation density, distance to a wetland, distance to forest edge, or distance to the nearest ecotone did not differ (P > 0.05) between depredated and undisturbed nests. We suggest that daily visitation of duck nests increases depredation, but longer intervals, typical of most nest studies, do not. High nesting densities, which could occur when flooding limits nesting habitat, may result in higher depredation rates.

MIMICKING COUNTERFACTUAL OUTCOMES TO ESTIMATE CAUSAL EFFECTS.

PubMed

Lok, Judith J

2017-04-01

In observational studies, treatment may be adapted to covariates at several times without a fixed protocol, in continuous time. Treatment influences covariates, which influence treatment, which influences covariates, and so on. Then even time-dependent Cox-models cannot be used to estimate the net treatment effect. Structural nested models have been applied in this setting. Structural nested models are based on counterfactuals: the outcome a person would have had had treatment been withheld after a certain time. Previous work on continuous-time structural nested models assumes that counterfactuals depend deterministically on observed data, while conjecturing that this assumption can be relaxed. This article proves that one can mimic counterfactuals by constructing random variables, solutions to a differential equation, that have the same distribution as the counterfactuals, even given past observed data. These "mimicking" variables can be used to estimate the parameters of structural nested models without assuming the treatment effect to be deterministic.

Evaluating nest supplementation as a recovery strategy for the endangered rodents of the Florida Keys

USGS Publications Warehouse

Cove, Michael V.; Simons, Theodore R.; Gardner, Beth; Maurer, Andrew S.; O'Connell, Allan F.

2017-01-01

The Key Largo woodrat (Neotoma floridana smalli) and Key Largo cotton mouse (Peromyscus gossypinus allapaticola) are federally endangered subspecies endemic to the tropical hardwood hammocks of Key Largo, Florida. Woodrats are considered generalists in habitat and diet, yet a steady decline in natural stick nests and capture rates over the past several decades suggests that they are limited by the availability of nesting habitat due to habitat loss and fragmentation. The more specialized Key Largo cotton mouse appears to rely on old growth hammock, a habitat type that is rare following past land clearing. In 2004, the U.S. Fish and Wildlife Service started building supplemental nest structures to restore habitat quality and connectivity for these endangered rodents, but nest use requires evaluation. We used camera traps and occupancy models to evaluate the factors influencing woodrat and cotton mouse use of the supplemental nests. We detected woodrats at 65 and cotton mice at 175 of 284 sampled nest structures, with co-occurrence at 38 nests. Woodrat nest use followed a gradient from low nest use in the north to high nest use in the south, which might relate to the proximity of free-ranging domestic cat (Felis catus) colonies in residential developments. Cotton mouse nest use, however, was related positively to mature hammock and related negatively to disturbed areas (e.g. scarified lands). The two species occurred independently of each other. Stick-stacking behavior was observed at supplemental nests and, although it was correlated with detection of woodrats, it was not a strong predictor of their occurrence. We suggest that nest supplementation can be an important tool for species recovery as habitat quality continues to improve with succession.

Interaction in Balanced Cross Nested Designs

NASA Astrophysics Data System (ADS)

Ramos, Paulo; Mexia, João T.; Carvalho, Francisco; Covas, Ricardo

2011-09-01

Commutative Jordan Algebras, CJA, are used in the study of mixed models obtained, through crossing and nesting, from simpler ones. In the study of cross nested models the interaction between nested factors have been systematically discarded. However this can constitutes an artificial simplification of the models. We point out that, when two crossed factors interact, such interaction is symmetric, both factors playing in it equivalent roles, while when two nested factors interact, the interaction is determined by the nesting factor. These interactions will be called interactions with nesting. In this work we present a coherent formulation of the algebraic structure of models enabling the choice of families of interactions between cross and nested factors using binary operations on CJA.

Baseline plasma corticosterone, haematological and biochemical results in nesting and rehabilitating loggerhead sea turtles (Caretta caretta).

PubMed

Flower, Jennifer E; Norton, Terry M; Andrews, Kimberly M; Nelson, Steven E; Parker, Clare E; Romero, L Michael; Mitchell, Mark A

2015-01-01

The evaluation of hormonal responses to stress in reptiles relies on acquisition of baseline corticosterone concentrations; however, the stress associated with the restraint needed to collect the blood samples can affect the results. The purpose of this study was to determine a time limit for the collection of blood samples to evaluate baseline corticosterone, haematological and biochemical results in nesting (n = 11) and rehabilitating (n = 16) loggerhead sea turtles (Caretta caretta). Blood samples were collected from the dorsal cervical sinus of each turtle immediately after touching the animal (t 0; 0-3 min) and 3 (t 3; 3-6 min), 6 (t 6; 6-9 min; nesting turtles only), 10 (t 10; 10-13 min) and 30 min (t 30; rehabilitating turtles only) after the initial hands-on time. Consistent between the rehabilitating and nesting turtles, there was a subtle yet significant increase in white blood cell counts over time. Despite the fact that white blood cell counts increased during the sampling period, there was no direct correlation between white blood cell count and corticosterone in the sampled turtles. In the nesting turtles, significant elevations in corticosterone were noted between t 0 and t 3 (P = 0.014) and between t 0 and t 6 (P = 0.022). Values at t 10 were not significantly different from those at t 0 (P = 0.102); however, there was a trend for the corticosterone values to continue to increase. These results suggest that sampling of nesting loggerhead sea turtles within 3 min of handling will provide baseline corticosterone concentrations in their natural environment. Significant elevations in corticosterone were also noted in the rehabilitating loggerhead sea turtles between t 0 and t 10 (P = 0.02) and between t 0 and t 30 of sampling (P = 0.0001). These results suggest that sampling of loggerhead sea turtles within 6 min of handling should provide baseline corticosterone concentrations in a rehabilitation setting. The delay in the corticosterone response noted in the rehabilitating turtles may be associated with the daily contact (visual or direct) they have with their human caretakers.

Discriminating the Drivers of Edge Effects on Nest Predation: Forest Edges Reduce Capture Rates of Ship Rats (Rattus rattus), a Globally Invasive Nest Predator, by Altering Vegetation Structure

PubMed Central

Ruffell, Jay; Didham, Raphael K.; Barrett, Paul; Gorman, Nic; Pike, Rhonda; Hickey-Elliott, Andrée; Sievwright, Karin; Armstrong, Doug P.

2014-01-01

Forest edges can strongly affect avian nest success by altering nest predation rates, but this relationship is inconsistent and context dependent. There is a need for researchers to improve the predictability of edge effects on nest predation rates by examining the mechanisms driving their occurrence and variability. In this study, we examined how the capture rates of ship rats, an invasive nest predator responsible for avian declines globally, varied with distance from the forest edge within forest fragments in a pastoral landscape in New Zealand. We hypothesised that forest edges would affect capture rates by altering vegetation structure within fragments, and that the strength of edge effects would depend on whether fragments were grazed by livestock. We measured vegetation structure and rat capture rates at 488 locations ranging from 0–212 m from the forest edge in 15 forest fragments, seven of which were grazed. Contrary to the vast majority of previous studies of edge effects on nest predation, ship rat capture rates increased with increasing distance from the forest edge. For grazed fragments, capture rates were estimated to be 78% lower at the forest edge than 118 m into the forest interior (the farthest distance for grazed fragments). This relationship was similar for ungrazed fragments, with capture rates estimated to be 51% lower at the forest edge than 118 m into the forest interior. A subsequent path analysis suggested that these ‘reverse’ edge effects were largely or entirely mediated by changes in vegetation structure, implying that edge effects on ship rats can be predicted from the response of vegetation structure to forest edges. We suggest the occurrence, strength, and direction of edge effects on nest predation rates may depend on edge-driven changes in local habitat when the dominant predator is primarily restricted to forest patches. PMID:25412340

Discriminating the drivers of edge effects on nest predation: forest edges reduce capture rates of ship rats (Rattus rattus), a globally invasive nest predator, by altering vegetation structure.

PubMed

Ruffell, Jay; Didham, Raphael K; Barrett, Paul; Gorman, Nic; Pike, Rhonda; Hickey-Elliott, Andrée; Sievwright, Karin; Armstrong, Doug P

2014-01-01

Forest edges can strongly affect avian nest success by altering nest predation rates, but this relationship is inconsistent and context dependent. There is a need for researchers to improve the predictability of edge effects on nest predation rates by examining the mechanisms driving their occurrence and variability. In this study, we examined how the capture rates of ship rats, an invasive nest predator responsible for avian declines globally, varied with distance from the forest edge within forest fragments in a pastoral landscape in New Zealand. We hypothesised that forest edges would affect capture rates by altering vegetation structure within fragments, and that the strength of edge effects would depend on whether fragments were grazed by livestock. We measured vegetation structure and rat capture rates at 488 locations ranging from 0-212 m from the forest edge in 15 forest fragments, seven of which were grazed. Contrary to the vast majority of previous studies of edge effects on nest predation, ship rat capture rates increased with increasing distance from the forest edge. For grazed fragments, capture rates were estimated to be 78% lower at the forest edge than 118 m into the forest interior (the farthest distance for grazed fragments). This relationship was similar for ungrazed fragments, with capture rates estimated to be 51% lower at the forest edge than 118 m into the forest interior. A subsequent path analysis suggested that these 'reverse' edge effects were largely or entirely mediated by changes in vegetation structure, implying that edge effects on ship rats can be predicted from the response of vegetation structure to forest edges. We suggest the occurrence, strength, and direction of edge effects on nest predation rates may depend on edge-driven changes in local habitat when the dominant predator is primarily restricted to forest patches.

Territory and nest site selection patterns by Grasshopper Sparrows in southeastern Arizona

USGS Publications Warehouse

Ruth, Janet M.; Skagen, Susan K.

2017-01-01

Grassland bird populations are showing some of the greatest rates of decline of any North American birds, prompting measures to protect and improve important habitat. We assessed how vegetation structure and composition, habitat features often targeted for management, affected territory and nest site selection by Grasshopper Sparrows (Ammodramus savannarum ammolegus) in southeastern Arizona. To identify features important to males establishing territories, we compared vegetation characteristics of known territories and random samples on 2 sites over 5 years. We examined habitat selection patterns of females by comparing characteristics of nest sites with territories over 3 years. Males selected territories in areas of sparser vegetation structure and more tall shrubs (>2 m) than random plots on the site with low shrub densities. Males did not select territories based on the proportion of exotic grasses. Females generally located nest sites in areas with lower small shrub (1–2 m tall) densities than territories overall when possible and preferentially selected native grasses for nest construction. Whether habitat selection was apparent depended upon the range of vegetation structure that was available. We identified an upper threshold above which grass structure seemed to be too high and dense for Grasshopper Sparrows. Our results suggest that some management that reduces vegetative structure may benefit this species in desert grasslands at the nest and territory scale. However, we did not assess initial male habitat selection at a broader landscape scale where their selection patterns may be different and could be influenced by vegetation density and structure outside the range of values sampled in this study.

Comparative population structure of cavity-nesting sea ducks

USGS Publications Warehouse

Pearce, John M.; Eadie, John M.; Savard, Jean-Pierre L.; Christensen, Thomas K.; Berdeen, James; Taylor, Eric J.; Boyd, Sean; Einarsson, Árni

2014-01-01

A growing collection of mtDNA genetic information from waterfowl species across North America suggests that larger-bodied cavity-nesting species exhibit greater levels of population differentiation than smaller-bodied congeners. Although little is known about nest-cavity availability for these species, one hypothesis to explain differences in population structure is reduced dispersal tendency of larger-bodied cavity-nesting species due to limited abundance of large cavities. To investigate this hypothesis, we examined population structure of three cavity-nesting waterfowl species distributed across much of North America: Barrow's Goldeneye (Bucephala islandica), Common Goldeneye (B. clangula), and Bufflehead (B. albeola). We compared patterns of population structure using both variation in mtDNA control-region sequences and band-recovery data for the same species and geographic regions. Results were highly congruent between data types, showing structured population patterns for Barrow's and Common Goldeneye but not for Bufflehead. Consistent with our prediction, the smallest cavity-nesting species, the Bufflehead, exhibited the lowest level of population differentiation due to increased dispersal and gene flow. Results provide evidence for discrete Old and New World populations of Common Goldeneye and for differentiation of regional groups of both goldeneye species in Alaska, the Pacific Northwest, and the eastern coast of North America. Results presented here will aid management objectives that require an understanding of population delineation and migratory connectivity between breeding and wintering areas. Comparative studies such as this one highlight factors that may drive patterns of genetic diversity and population trends.

Reproductive ecology of the Maui Parrotbill

USGS Publications Warehouse

Simon, John C.; Pratt, T.K.; Berlin, Kim E.; Kowalsky, James R.

2000-01-01

The endangered Maui Parrotbill (Pseudonestor xanthophrys) is an excavating, insectivorous Hawaiian honeycreeper endemic to the high elevation rain forests of east Maui, Hawaii. From March 1994 to June 1997, we studied various aspects of their breeding ecology. We color-banded 18 individuals, located and monitored 9 active nests, and took behavioral data during 440 hrs of nest observation. Both members of a pair maintained a year-round, all-purpose territory that included nest sites and food resources. Maui Parrotbill were monogamous within and between years; we found no evidence of polyandry, polygyny, or helpers at the nest. Nests were cup-shaped, composed mainly of lichen interlaced with small twigs, and positioned in the outer canopy forks of mature ohia (Metrosideros polymorpha) trees. Modal clutch size was one. Females performed most nest construction and all incubation and brooding; males provisioned females and assisted in feeding nestlings after their fourth day. Fledglings depended on parental care for 5-8 months, during which their bill strength increased and foraging skills improved. We calculated the overall nest success rate by the Mayfield Method as 0.42 for the 1995/1996 and 1996/1997 breeding seasons combined. Nest failure and fledgling disappearance coincided with events of high rainfall. Their breeding ecology most closely resembled the Akiapolaau (Hemignathus munroi), another excavating, insectivorous Hawaiian honeycreeper found on Hawaii Island. As with the Akiapolaau, the threat of extinction is persistent and results from both the constraints of inherent life history traits and artificial ecological changes. We advocate the protection and expansion of habitable forest areas and an ongoing program to monitor and mitigate the effects of invasive species.

Predation risk of artificial ground nests in managed floodplain meadows

NASA Astrophysics Data System (ADS)

Arbeiter, Susanne; Franke, Elisabeth

2018-01-01

Nest predation highly determines the reproductive success in birds. In agricultural grasslands, vegetation characteristics and management practices influences the predation risk of ground breeders. Little is known so far on the predation pressure on non-passerine nests in tall swards. Investigations on the interaction of land use with nesting site conditions and the habitat selection of nest predators are crucial to develop effective conservation measures for grassland birds. In this study, we used artificial nests baited with quail and plasticine eggs to identify potential predators of ground nests in floodplain meadows and related predation risk to vegetation structure and grassland management. Mean daily predation rate was 0.01 (±0.012) after an exposure duration of 21 days. 70% of all observed nest predations were caused by mammals (Red Fox and mustelids) and 17.5% by avian predators (corvids). Nest sites close to the meadow edge and those providing low forb cover were faced with a higher daily predation risk. Predation risk also increased later in the season. Land use in the preceding year had a significant effect on predation risk, showing higher predation rates on unmanaged sites than on mown sites. Unused meadows probably attract mammalian predators, because they provide a high abundance of small rodents and a more favourable vegetation structure for foraging, increasing also the risk of incidental nest predations. Although mowing operation is a major threat to ground-nesting birds, our results suggest that an annual removal of vegetation may reduce predation risk in the subsequent year.

Nesting in an Object Oriented Language is NOT for the Birds

NASA Astrophysics Data System (ADS)

Buhr, P. A.; Zarnke, C. R.

The notion of nested blocks has come into disfavour or has been ignored in recent program language design. Many of the current object oriented programming languages use subclassing as the sole mechanism to establish relationships between classes and have no general notion of nesting. We argue that nesting (and, more generally, hierarchical organization) is a powerful mechanism that provides facilities that are not otherwise possible in a class based programming language. We agree that traditional block structure and its associated nesting have severe problems, and we suggest several extensions to the notion of blocks and block structure that indirectly make nesting a useful and powerful mechanism, particularly in an object oriented programming system. The main extension is to allow references to definitions from outside of the containing block, thereby making the contained definitions available in a larger scope. References are made using either the name of the containing entity or an instance of the containing entity. The extensions suggest a way to organize the programming environment for a large, multi-user system. These facilities are not available with subclassing, and subclassing provides facilities not available by nesting; hence, an object oriented language can benefit by providing nesting as well.

Sound absorption of a new oblique-section acoustic metamaterial with nested resonator

NASA Astrophysics Data System (ADS)

Gao, Nansha; Hou, Hong; Zhang, Yanni; Wu, Jiu Hui

2018-02-01

This study designs and investigates high-efficiency sound absorption of new oblique-section nested resonators. Impedance tube experiment results show that different combinations of oblique-section nest resonators have tunable low-frequency bandwidth characteristics. The sound absorption mechanism is due to air friction losses in the slotted region and the sample structure resonance. The acousto-electric analogy model demonstrates that the sound absorption peak and bandwidth can be modulated over an even wider frequency range by changing the geometric size and combinations of structures. The proposed structure can be easily fabricated and used in low-frequency sound absorption applications.

Formation mechanism of photo-induced nested wrinkles on siloxane-photomonomer hybrid film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Kazumasa; International Laboratory of Materials Science and Nanotechnology; Laboratorio di Scienz

Nested wrinkle structures, hierarchical surface wrinkles of different periodicities of sub-μm and tens-μm, have been fabricated on a siloxane-photomonomer hybrid film via a photo-induced surface polymerization of acrylamide. The formation mechanism of the nested wrinkle structures is examined based on a time-dependent structure observation and chemical composition analyses. In-situ observation of the evolving surface structure showed that sub-μm scale wrinkles first formed, subsequently the tens-μm scale ones did. In-situ FT-IR analysis indicated that the nested wrinkles formation took place along with the development of siloxane network of under layer. A cross sectional observation of the film revealed that the filmmore » was composed of three layers. FT-IR spectra of the film revealed that the surface and interior layers were polyacrylamide rich layer and siloxane-polymer rich layer, respectively. The intermediate layer formed as a diffusion layer by migration of acrylamide from interior to the surface. These three layers have different chemical compositions and therefore different mechanical characteristics, which allows the wrinkle formation. Shrinkage of siloxane-polymer interior layers, as a result of polycondensation of siloxane network, induced mechanical instabilities at interlayers, to form the nested wrinkle structures.« less

Risky business: Site selection by Acadian Flycatchers under threat of nest predation and brood parasitism

USGS Publications Warehouse

HazIer, K.R.; Cooper, R.J.; Twedt, D.J.

2006-01-01

Habitat quality is determined not only by habitat structure and the availability of resources, but also by competitors, cooperators, predators, and parasites. We hypothesized that, for passerines, minimizing risk from avian nest predators and brood parasites is an important factor in selecting a breeding site. Through the early part of two breeding seasons, we spot-mapped locations of Acadian Flycatchers (Empidonax virescens, territory selectors), Red-bellied Woodpeckers (Melanerpes carolinus, nest predators) and Brown-headed Cowbirds (Molothrus ater, brood parasites) in a 56-ha study area within an extensive bottomland hardwood forest. We were thereby able to determine the order of flycatcher territory settlement and nest initiation in relation to risk of predation and parasitism, while accounting for habitat structure. Male settlement was influenced by both habitat structure and risk avoidance. However, risk trom woodpeckers was relatively more important in the first season and risk from cowbirds in the second, evidently due to differences in the relative abundance of predator and brood-parasite in each year. For male flycatchers, settlement choices appear to be flexible in the face of changing 'risk landscapes.' For females, habitat structure was the most important predictor of nest site selection. Even so, there was evidence that females avoided cowbirds. Surprisingly, nest site selection was positively associated with woodpecker abundance in the first season when woodpeckers were present in greater numbers. Possible explanations for this contradictory result are discussed.

Flexible social organization and high incidence of drifting in the sweat bee, Halictus scabiosae.

PubMed

Ulrich, Yuko; Perrin, Nicolas; Chapuisat, Michel

2009-04-01

The very diverse social systems of sweat bees make them interesting models to study social evolution. Here we focus on the dispersal behaviour and social organization of Halictus scabiosae, a common yet poorly known species of Europe. By combining field observations and genetic data, we show that females have multiple reproductive strategies, which generates a large diversity in the social structure of nests. A detailed microsatellite analysis of 60 nests revealed that 55% of the nests contained the offspring of a single female, whereas the rest had more complex social structures, with three clear cases of multiple females reproducing in the same nest and frequent occurrence of unrelated individuals. Drifting among nests was surprisingly common, as 16% of the 122 nests in the overall sample and 44% of the nests with complex social structure contained females that had genotypes consistent with being full-sisters of females sampled in other nests of the population. Drifters originated from nests with an above-average productivity and were unrelated to their nestmates, suggesting that drifting might be a strategy to avoid competition among related females. The sex-specific comparison of genetic differentiation indicated that dispersal was male-biased, which would reinforce local resource competition among females. The pattern of genetic differentiation among populations was consistent with a dynamic process of patch colonization and extinction, as expected from the unstable, anthropogenic habitat of this species. Overall, our data show that H. scabiosae varies greatly in dispersal behaviour and social organization. The surprisingly high frequency of drifters echoes recent findings in wasps and bees, calling for further investigation of the adaptive basis of drifting in the social insects.

Nested mesoscale-to-LES modeling of the atmospheric boundary layer in the presence of under-resolved convective structures

DOE PAGES

Mazzaro, Laura J.; Munoz-Esparza, Domingo; Lundquist, Julie K.; ...

2017-07-06

Multiscale atmospheric simulations can be computationally prohibitive, as they require large domains and fine spatiotemporal resolutions. Grid-nesting can alleviate this by bridging mesoscales and microscales, but one turbulence scheme must run at resolutions within a range of scales known as the terra incognita (TI). TI grid-cell sizes can violate both mesoscale and microscale subgrid-scale parametrization assumptions, resulting in unrealistic flow structures. Herein we assess the impact of unrealistic lateral boundary conditions from parent mesoscale simulations at TI resolutions on nested large eddy simulations (LES), to determine whether parent domains bias the nested LES. We present a series of idealized nestedmore » mesoscale-to-LES runs of a dry convective boundary layer (CBL) with different parent resolutions in the TI. We compare the nested LES with a stand-alone LES with periodic boundary conditions. The nested LES domains develop ~20% smaller convective structures, while potential temperature profiles are nearly identical for both the mesoscales and LES simulations. The horizontal wind speed and surface wind shear in the nested simulations closely resemble the reference LES. Heat fluxes are overestimated by up to ~0.01 K m s –1 in the top half of the PBL for all nested simulations. Overestimates of turbulent kinetic energy (TKE) and Reynolds stress in the nested domains are proportional to the parent domain's grid-cell size, and are almost eliminated for the simulation with the finest parent grid-cell size. Furthermore, based on these results, we recommend that LES of the CBL be forced by mesoscale simulations with the finest practical resolution.« less

Nested mesoscale-to-LES modeling of the atmospheric boundary layer in the presence of under-resolved convective structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazzaro, Laura J.; Munoz-Esparza, Domingo; Lundquist, Julie K.

Multiscale atmospheric simulations can be computationally prohibitive, as they require large domains and fine spatiotemporal resolutions. Grid-nesting can alleviate this by bridging mesoscales and microscales, but one turbulence scheme must run at resolutions within a range of scales known as the terra incognita (TI). TI grid-cell sizes can violate both mesoscale and microscale subgrid-scale parametrization assumptions, resulting in unrealistic flow structures. Herein we assess the impact of unrealistic lateral boundary conditions from parent mesoscale simulations at TI resolutions on nested large eddy simulations (LES), to determine whether parent domains bias the nested LES. We present a series of idealized nestedmore » mesoscale-to-LES runs of a dry convective boundary layer (CBL) with different parent resolutions in the TI. We compare the nested LES with a stand-alone LES with periodic boundary conditions. The nested LES domains develop ~20% smaller convective structures, while potential temperature profiles are nearly identical for both the mesoscales and LES simulations. The horizontal wind speed and surface wind shear in the nested simulations closely resemble the reference LES. Heat fluxes are overestimated by up to ~0.01 K m s –1 in the top half of the PBL for all nested simulations. Overestimates of turbulent kinetic energy (TKE) and Reynolds stress in the nested domains are proportional to the parent domain's grid-cell size, and are almost eliminated for the simulation with the finest parent grid-cell size. Furthermore, based on these results, we recommend that LES of the CBL be forced by mesoscale simulations with the finest practical resolution.« less

From neurons to nests: nest-building behaviour as a model in behavioural and comparative neuroscience.

PubMed

Hall, Zachary J; Meddle, Simone L; Healy, Susan D

Despite centuries of observing the nest building of most extant bird species, we know surprisingly little about how birds build nests and, specifically, how the avian brain controls nest building. Here, we argue that nest building in birds may be a useful model behaviour in which to study how the brain controls behaviour. Specifically, we argue that nest building as a behavioural model provides a unique opportunity to study not only the mechanisms through which the brain controls behaviour within individuals of a single species but also how evolution may have shaped the brain to produce interspecific variation in nest-building behaviour. In this review, we outline the questions in both behavioural and comparative neuroscience that nest building could be used to address, summarize recent findings regarding the neurobiology of nest building in lab-reared zebra finches and across species building different nest structures, and suggest some future directions for the neurobiology of nest building.

Consequences of elevating plasma testosterone in females of a socially monogamous songbird: evidence of constraints on male evolution?

PubMed

Clotfelter, Ethan D; O'Neal, Dawn M; Gaudioso, Jacqueline M; Casto, Joseph M; Parker-Renga, Ian M; Snajdr, Eric A; Duffy, Deborah L; Nolan, Val; Ketterson, Ellen D

2004-08-01

To explore whether selection for testosterone-mediated traits in males might be constrained by costs of higher testosterone to females, we examined the effects of experimental elevation of plasma testosterone on physiological, reproductive, and behavioral parameters in a female songbird, the dark-eyed junco (Junco hyemalis). We used subcutaneous implants to elevate testosterone (T) in captive and free-living female juncos. In captive birds, we measured the effects of high T on body mass, feather molt, and brood patch formation. In the field, we monitored its effects on the timing of egg laying, clutch size, egg size, egg steroid levels, incubation, and nest-defense behavior. Females implanted with testosterone (T-females) had significantly higher circulating levels of testosterone than did control females (C-females). Captive T-females had lower body mass, were less likely to develop brood patches, and delayed feather molt relative to C-females. Among free-living females, the interval between nest completion and appearance of the first egg was longer for T-females than for C-females and egg yolk concentrations of testosterone were higher, but there were no significant differences in estradiol levels, clutch size, or egg size. Incubation and nest defense behavior were also similar between T- and C-females. Our results suggest that selection on males for higher testosterone might initially lead to a correlated response in females producing changes in body mass and feather molt, both of which could be detrimental. Other possible female responses would be delayed onset of reproduction, which might reduce reproductive success, and higher yolk testosterone, which might have either positive or negative effects on offspring development. We found no reason to expect reduced parental behavior by females as a negative fitness consequence of selection for higher testosterone in males.

A Nested or Composite Shatter Cone Structure in the South Range of Sudbury

NASA Astrophysics Data System (ADS)

Hurwitz, D. M.; Zanetti, M.; Lucas, M. P.; Anders, D.; Kramer, G.; Thomson, O.; Kring, D. A.; Osinski, G. R.

2013-08-01

In a recent survey of Sudbury shatter cones, we identified an outcrop of stacked, curvilinear foliations with well-developed, nested shatter cones that trend toward the apex of the foliations. We interpret this structure as a composite cone.

Variation in spatial scale of competing polydomous twig-nesting ants in coffee agroecosystems

PubMed Central

Mathis, Kaitlyn A.; Philpott, Stacy M.; Ramirez, Santiago R.

2016-01-01

Arboreal ants are both highly diverse and ecologically dominant in the tropics. This ecologically important group is particularly useful in ongoing efforts to understand processes that regulate species diversity and coexistence. Our study addresses how polydomy can influence patterns of nest occupation in competing arboreal ants. We examined the spatial structure of nest occupation (nest distance, abundance and density) in three polydomous co-occurring twig-nesting ant species (Pseudomyrmex simplex, P. ejectus and P. PSW-53) by mapping twigs occupied by ants from each species within plots in our study site. We then used two colony structure estimators (intraspecific aggression and cuticular hydrocarbon variation) to determine the relative degree of polydomy for each species. All work was conducted in coffee agroforests in Chiapas, Mexico. Our results revealed that the two species with highest abundance and nest density were also highly polydomous, where both species had either single or multiple non-aggressive colonies occupying nests on a large spatial scale (greater than the hectare level). Our results also indicate that the species with the lowest abundance and density is less polydomous, occupying several overlapping and territorial colonies at the hectare level in which multiple colonies never co-occur on the same host plant. These results contribute evidence that successful coexistence and highly polydomous colony structure may allow ants, through reduced intraspecific aggression, to successfully occupy more nests more densely than ant species that have multiple territorial colonies. Furthermore our study highlights the importance of considering intraspecific interactions when examining community assembly of ants. PMID:27795573

Selection of anthropogenic features and vegetation characteristics by nesting Common Ravens in the sagebrush ecosystem

USGS Publications Warehouse

Howe, Kristy B.; Coates, Peter S.; Delehanty, David J.

2014-01-01

Common Raven (Corvus corax) numbers and distribution are increasing throughout the sagebrush steppe, influencing avian communities in complex ways. Anthropogenic structures are thought to increase raven populations by providing food and nesting subsidies, which is cause for concern because ravens are important nest predators of sensitive species, including Greater Sage-Grouse (Centrocercus urophasianus). During 2007–2009, we located raven nests in southeastern Idaho and conducted a resource selection analysis. We measured variables at multiple spatial scales for 72 unique nest locations, including landscape-level vegetation characteristics and anthropogenic structures. Using generalized linear mixed models and an information-theoretic approach, we found a 31% decrease in the odds of nesting by ravens for every 1 km increase in distance away from a transmission line. Furthermore, a 100-m increase in distance away from the edge of two different land cover types decreased the odds of nesting by 20%, and an increase in the amount of edge by 1 km within an area of 102.1 ha centered on the nest increased the odds of nesting by 49%. A post hoc analysis revealed that ravens were most likely to nest near edges of adjoining big sagebrush (Artemisia tridentata) and land cover types that were associated with direct human disturbance or fire. These findings contribute to our understanding of raven expansion into rural environments and could be used to make better-informed conservation decisions, especially in the face of increasing renewable energy development.

Marine turtles are not fussy nesters: a novel test of small-scale nest site selection using structure from motion beach terrain information

PubMed Central

Leon, Javier X.; Gilby, Ben L.; Olds, Andrew D.; Schlacher, Thomas A.

2017-01-01

Background Nest selection is widely regarded as a key process determining the fitness of individuals and viability of animal populations. For marine turtles that nest on beaches, this is particularly pivotal as the nesting environment can significantly control reproductive success.The aim of this study was to identify the environmental attributes of beaches (i.e., morphology, vegetation, urbanisation) that may be associated with successful oviposition in green and loggerhead turtle nests. Methods We quantified the proximity of turtle nests (and surrounding beach locations) to urban areas, measured their exposure to artificial light, and used ultra-high resolution (cm-scale) digital surface models derived from Structure-from-Motion (SfM) algorithms, to characterise geomorphic and vegetation features of beaches on the Sunshine Coast, eastern Australia. Results At small spatial scales (i.e., <100 m), we found no evidence that turtles selected nest sites based on a particular suite of environmental attributes (i.e., the attributes of nest sites were not consistently different from those of surrounding beach locations). Nest sites were, however, typically characterised by occurring close to vegetation, on parts of the shore where the beach- and dune-face was concave and not highly rugged, and in areas with moderate exposure to artificial light. Conclusion This study used a novel empirical approach to identify the attributes of turtle nest sites from a broader ‘envelope’ of environmental nest traits, and is the first step towards optimizing conservation actions to mitigate, at the local scale, present and emerging human impacts on turtle nesting beaches. PMID:28070454

Industrious leaf cutter ants and their carbon footprints

NASA Astrophysics Data System (ADS)

Swanson, A. C.; Dierick, D.; Trahan, N. A.; Allen, M. F.; Schwendenmann, L.; Harmon, T. C.; Oberbauer, S. F.; Fernandez Bou, A. S.; Zelikova, T. J.

2017-12-01

Leaf cutter ants (LCA) are considered ecosystem engineers in Neotropical forest ecosystems because they alter physical and environmental conditions for other organisms. LCA excavate large underground nests, maintaining intricate tunnels and fungal and waste chambers, and they continuously bring in vast amounts of fresh leaf material. In order to understand their ecosystem-wide impacts, we set out to determine whether their engineering activities fundamentally alter soil structure, soil nutrient pools, and gas fluxes in a wet tropical rainforest in Costa Rica. To directly compare LCA nest to non-nest sites, we utilized embedded sensor arrays with series of soil moisture, CO2, O2, and temperature sensors placed at four soil depths and automated minirhizotrons (AMR) to measure root and hyphal production and turnover. We also collected soils for biogeochemical analyses and measured soil CO2 fluxes and carbon isotope ratios of below-ground CO2 for two years. Our measurements confirmed that LCA alter their soil environment to regulate internal soil CO2 concentrations, moisture, and temperature, increasing O2 concentrations in the process. There were marked differences in soil structure inside nests relative to non-nests and these were associated with increased root and hyphal production and turnover in nests. Soil C, N, P, and their respective degrading enzymes were highly variable among sites and between nests and controls but N and P increased with soil depth and were generally higher in nests than controls. Contrary to our expectations, C mineralization rates were lower in nests but CO2 fluxes were high from nest vents and similar to non-nests elsewhere. At the system scale, LCA appear to fundamentally change the soil environment inside their nests and create spatial heterogeneity in biogeochemical processes and root and hyphal growth, influencing the overall C balance of Neotropical forests.

Nesting ecology of roseate spoonbills at Nueces Bay, Texas

USGS Publications Warehouse

White, Donald H.; Mitchell, Christine A.; Cromartie, E.

1982-01-01

We conducted a study in 1978-1980 of the nesting ecology of Roseate Spoonbills (Ajaia ajaja) in a relatively polluted environment at Nueces Bay, Texas. For 154 marked nests, the average clutch size was 3.0 eggs; 73% of the eggs hatched, and 87% of the nests were successful (hatched at least 1 young). The average nest success rate (total fledglings:total eggs) was 50% or 1.5 fledglings per total nests. Incubation began the day after the first egg was laid, and the incubation period for each egg was 22 days. Eggs hatched in the order that they were laid; the first and second eggs hatched on consecutive days, and the second, third, and fourth eggs hatched every other day. Nest composition and size were highly consistent, but nest placement varied considerably and was dependent on the vegetative configuration of the dredge-material islands. Growth rate of nestlings conformed to a 'standard' growth curve, where body weight of nestlings at fledging equaled that of adults. There was no difference in weight gain among siblings based on actual age. Nestlings fledged at about 6 weeks of age, when feather development was complete. At fledging, the bills of juveniles had almost reached adult width, but bill length was only 67% that of adults. In general, environmental pollutants were low (<2 ppm) in spoonbill eggs, though a few eggs contained elevated concentrations of DDE (up to 15 ppm, wet weight). Some eggshells were 5% thinner than those in museum collections, but the degree of thinning was not within the range known to cause population declines. We conclude that organochlorine pollutants are not adversely affecting spoonbill reproduction at Nueces Bay, Texas, though the area is surrounded by industries and agricultural lands. Apparently, spoonbills are less sensitive to these contaminants than are other aquatic species.

Welfare indicators in laying hens in relation to nest exclusion.

PubMed

Alm, M; Tauson, R; Holm, L; Wichman, A; Kalliokoski, O; Wall, H

2016-06-01

Consumer concerns about the welfare of laying hens are increasing, leading to increased interest in identifying reliable ways to assess welfare. The present study evaluated invasive and non-invasive welfare indicators in relation to a stressful challenge. The study included 126 Lohmann Selected Leghorn hens housed in furnished cages. Welfare indicators were measured between 61 and 70 wk of age in birds excluded from their nests for 5 consecutive d and control birds that had continuous access to nests. Baseline recordings were carried out in both groups prior to and post exclusion period. The assessed indicators were: corticosterone metabolites in droppings (FCM), corticosterone concentration in yolk, corticosterone concentration in plasma, irregularities of eggshells, heterophil to lymphocyte (H:L) ratio, tonic immobility duration, and feather cover. Behavioral observations showed that the birds had a clear preference for using the secluded nest sites, confirming that they were likely to perceive nest exclusion as an undesirable experience. Further, elevated levels of FCM in droppings, yolk corticosterone concentrations, H:L ratios and irregular eggshells were detected in both nest deprived and control birds during the exclusion. This suggests that these indicators were able to detect an increased stress response arising from nest deprivation, and it is hypothesized that the stress spread to birds in adjacent cages with access to nests. There was a positive and consistent correlation between FCM in droppings and eggshell irregularities, also supporting the use of eggshell irregularities as a potential non-invasive welfare indicator. However, the pattern of the stress response varied between indicators and correlations were generally few and inconsistent, highlighting the complexity of the relationship among welfare indicators. © 2016 Poultry Science Association Inc.

Shrub Nesting of the Red-Eyed Vireo in Relation to Structure of Aspen Forests

Treesearch

William J. Jr Mattson

1979-01-01

Nests were built in five species of high shrubs in four trembling aspen forests of northern Minnesoa. Nest densities ranged between 0.5 and 3.0 per acre and were positively related to the abundance3 of large (>1.2-cm diameter) shrub stems.

The Implications of Contamination for Educational Experiments with Two Levels of Nesting

ERIC Educational Resources Information Center

Rhoads, Christopher

2016-01-01

Experimental evaluations that involve the educational system usually involve a hierarchical structure (students are nested within classrooms that are nested within schools, etc.). Concerns about contamination, where research subjects receive certain features of an intervention intended for subjects in a different experimental group, have often led…

Breeding behavior of immature mourning doves

USGS Publications Warehouse

Irby, H.D.; Blankenship, L.H.

1966-01-01

Some immature mourning doves (Zenaidura mncroura) are capable of breeding in their first (calendar) year of life. The breeding activities of immatures observed in this study included calling, copulating, and nesting. Development of sexual structures such as cloacal papillae, oviduct openings, and gonads was also regarded as evidence of breeding potential. Immatures were identified principally by white-tipped wing coverts. Sexes were distinguished by behavioral characteristics. Males coo, perform flights, carry nest material, and attend nests during the day and females attend nests at night. Immatures were involved in at least ten nestings on two areas near Tucson, Arizona, in 1963. Five young fledged from these nests.

Effects of flow dynamics on the aquatic-terrestrial transition zone (ATTZ) of lower Missouri river sandbars with implications for selected biota

USGS Publications Warehouse

Tracy-Smith, Emily; Galat, David L.; Jacobson, Robert B.

2012-01-01

Sandbars are an important aquatic terrestrial transition zone (ATTZ) in the active channel of rivers that provide a variety of habitat conditions for riverine biota. Channelization and flow regulation in many large rivers have diminished sandbar habitats and their rehabilitation is a priority. We developed sandbar-specific models of discharge-area relationships to determine how changes in flow regime affect the area of different habitat types within the submerged sandbar ATTZ (depth) and exposed sandbar ATTZ (elevation) for a representative sample of Lower Missouri River sandbars. We defined six different structural habitat types within the sandbar ATTZ based on depth or exposed elevation ranges that are important to different biota during at least part of their annual cycle for either survival or reproduction. Scenarios included the modelled natural flow regime, current managed flow regime and two environmental flow options, all modelled within the contemporary river active channel. Thirteen point and wing-dike sandbars were evaluated under four different flow scenarios to explore the effects of flow regime on seasonal habitat availability for foraging of migratory shorebirds and wading birds, nesting of softshell turtles and nursery of riverine fishes. Managed flows provided more foraging habitat for shorebirds and wading birds and more nursery habitat for riverine fishes within the channelized reach sandbar ATTZ than the natural flow regime or modelled environmental flows. Reduced summer flows occurring under natural and environmental flow alternatives increased exposed sandbar nesting habitat for softshell turtle hatchling emergence. Results reveal how management of channelized and flow regulated large rivers could benefit from a modelling framework that couples hydrologic and geomorphic characteristics to predict habitat conditions for a variety of biota.

The Demand for Higher Education: A Static Structural Approach Accounting for Individual Heterogeneity and Nesting Patterns

ERIC Educational Resources Information Center

Flannery, Darragh; O'Donoghue, Cathal

2013-01-01

In this paper we estimate a structural model of higher education participation and labour choices in a static setting that accounts for individual heterogeneity and possible nesting structures in the decision process. We assume that young people that complete upper secondary education are faced with three choices, go to higher education, not go to…

Fire and shade effects on ground cover structure in Kirtland's warbler habitat

Treesearch

John R. Probst; Deahn DonnerWright

2003-01-01

Researchers and managers have suggested that a narrow range of ground-cover structure resulting from fire might be necessary for suitable Kirtland`s warbler nesting conditions. Yet, Kirtland`s warblers have bred successfully in numerous unburned stands and there is little direct evidence to indicate that ground cover structure is a limiting factor for nest sites or...

A low-disturbance capture technique for ground-nesting Double-crested Cormorants (Phalacrocorax auritus)

USGS Publications Warehouse

Courtot, Karen; Roby, Daniel D.; Kerr, Lauren H.; Lyons, Donald E.; Adkins, Jessica Y.

2016-01-01

Capturing breeding adults of colonially nesting species can entail risks of nest failure and even colony abandonment, especially in species that react strongly to human disturbance. A low-disturbance technique for capturing specific adult Double-crested Cormorants (Phalacrocorax auritus) at a ground-nesting colony was developed to reduce these risks and is described here. Nesting habitat enhancement was used to attract Doublecrested Cormorants to nest adjacent to above-ground tunnels constructed so that researchers could capture birds by hand. Using this technique, Double-crested Cormorants (n = 87) were captured during the incubation and chick-rearing stages of the nesting cycle. Unlike alternative capture techniques, this approach allowed targeting of specific individuals for capture and recapture, minimized local disturbance, and eliminated colony-wide disturbances. The tunnel-based system presented here could be adapted to capture adults or to access the nest contents of other ground-nesting colonial species that are inclined to nest in areas of enhanced nesting habitat and adapt to anthropogenic structures in their nesting area. This system would be particularly beneficial for other wary and easily disturbed species.

Seasonal changes in serum gonadal steroids associated with migration, mating, and nesting in the loggerhead sea turtle (Caretta caretta).

PubMed

Wibbels, T; Owens, D W; Limpus, C J; Reed, P C; Amoss, M S

1990-07-01

Adult male loggerhead sea turtles, Caretta caretta, exhibited a "prenuptial" spermatogenic cycle that was coincident with increased concentrations of serum testosterone (T). Serum T was high during the months when migration and mating have been recorded for males. In contrast to females, males appear to be annual breeders. Nine reproductively active female C. caretta (as verified through laparoscopy) were tagged with sonic transmitters and were repeatedly bled prior to migration. Four months prior to the nesting season, the ovaries of reproductively active females had hundreds of vitellogenic follicles of approximately 1.5 cm in diameter (i.e., half the size of ovulatory follicles). Approximately 4-6 weeks prior to migration from feeding grounds to mating and nesting areas, serum estradiol-17 beta (E2) concentrations increased significantly and remained high for approximately 4 weeks, suggesting a period of increased vitellogenesis. During a 1- to 2-week period prior to migration, serum E2 decreased significantly, while serum T concentrations increased (at least) until the time of migration. Serum T, E2, and progesterone (PRO) were elevated during nesting if a turtle was going to nest again during that nesting season. During the last nesting of a season, turtles had low serum concentrations of T, E2, and Pro. The prenuptial pattern of gonadal recrudescence and gonadal steroid production in both male and female C. caretta contrasts with those of many temperate freshwater turtles, and this type of reproductive pattern may have been facilitated by adaptation to a tropical marine environment.

Quantifying the social structure of a large captive flock of greater flamingos (Phoenicopterus roseus): Potential implications for management in captivity.

PubMed

Rose, Paul E; Croft, Darren P

2018-05-01

An appropriate social environment for species held in captivity is key for ensuring both good welfare and reproductive performance. Species with a complex social structure may suffer if their social requirements are not taken into consideration as part of management and husbandry strategies. Here we aim to understand the drivers of social structure, and the link between social structure and reproduction in a flock of 281 greater flamingos (Phoenicopterus roseus) at WWT Slimbridge Wetland Centre. Proximity-based associations between birds were measured three and four times per day (depending upon season and husbandry) from 2012 to 2016. To determine the effect of reproductive activity on social structure, display and nesting behaviour were also recorded for the 2015 breeding season (April-July). Results showed that birds displayed a wider range of social relationships, and that affiliations within the flock were not random. This flamingo flock was differentiated into discrete subgroups, and social structure was stable across some years, but not over all seasons. Social bonds were more consistent across seasons into the nesting period rather than outside of it. During breeding, not all birds that displayed built a nest, and not all displaying birds nested. Future research should further investigate differences in display and nesting patterns within a flock, and determine how the social structure of large flocks compares to smaller flocks of this species. Comparing captive data to information on wild bird sociality would be relevant to highlight any differences in patterns of assortment and connectivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Nested Structural Equation Models: Noncentrality and Power of Restriction Test.

ERIC Educational Resources Information Center

Raykov, Tenko; Penev, Spiridon

1998-01-01

Discusses the difference in noncentrality parameters of nested structural equation models and their utility in evaluating statistical power associated with the pertinent restriction test. Asymptotic confidence intervals for that difference are presented. These intervals represent a useful adjunct to goodness-of-fit indexes in assessing constraints…

Creation, management, and research on lakes and ponds at Patuxent Research Refuge

USGS Publications Warehouse

Perry, M.C.

1997-01-01

From 19391966, approximately 450 acres of impoundments were created for recreational and wildlife conservation purposes at Patuxent Research Refuge. Impoundments were of three major designs: impounded ravines, excavated basins, and impounded swamps. Over 50 species of wetland plants were transplanted to impoundments of Patuxent to determine best species for relatively infertile waters. The wood duck was the only waterfowl species commonly observed on the Refuge when the area was established. Waterfowl, including Canada geese, mallards, and black ducks, were introduced and numerous techniques developed to improve nesting and brood habitat. The impoundments also provide migration and wintering habitat to 24 species of waterfowl. Management techniques include drawdowns of water every 35 years in most impoundments to decrease problems from floating plants and to oxidize organic material. Drawdowns are timed to allow sufficient time for waterfowl brood development in the spring, but also allow optimum time for the development of plant species (e. g., red-rooted sedge and smartweed) that grow in moist soil conditions. This procedure has become known as moist-soil management and is now used on many state and federal wildlife refuges throughout the country. Research on the impounded wetlands at Patuxent during the 1950-70s included evaluation of vegetation in regard to water level management, nest box design to reduce use of boxes by starlings, and imprinting of waterfowl to elevated nesting structures to reduce predation on nests, especially from raccoons. During the 1980-90s, new smaller impoundments were constructed to increase the possibilities of conducting research on acid precipitation and to act as tertiary treatment of wastewater coming from the National Wildlife Visitor Center. Lakes and ponds at Patuxent Research Refuge are presently used for multiple purposes including wildlife habitat, flood control, nutrient removal, fire fighting, environmental education, recreation (especially fishing and hunting), and research.

The use of root plates for nesting sites by Anthophora abrupta (Hymenoptera: Apidae) may be common within forested habitats

Treesearch

Joshua W. Campbell; Cynthia C. Viguiera; Patrick Viguiera; John E. Hartgerink; Cathryn H. Greenberg

2017-01-01

This is the first reported use of root plates by Anthophora abrupta Say (Hymenoptera: Apidae). Previous reported nesting sites were vertical riverbanks and several man-made clay structures. Root plates in forested habitats may be the preferred nesting site for A. abrupta.

Nested Neural Networks

NASA Technical Reports Server (NTRS)

Baram, Yoram

1992-01-01

Report presents analysis of nested neural networks, consisting of interconnected subnetworks. Analysis based on simplified mathematical models more appropriate for artificial electronic neural networks, partly applicable to biological neural networks. Nested structure allows for retrieval of individual subpatterns. Requires fewer wires and connection devices than fully connected networks, and allows for local reconstruction of damaged subnetworks without rewiring entire network.

Delineation of Nested Wetland Catchments and Modeling of Hydrologic Connectivity Using LiDAR Data and Aerial Imagery

EPA Science Inventory

In traditional watershed delineation and topographic modelling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In r...

Baseline plasma corticosterone, haematological and biochemical results in nesting and rehabilitating loggerhead sea turtles (Caretta caretta)

PubMed Central

Flower, Jennifer E.; Norton, Terry M.; Andrews, Kimberly M.; Nelson, Steven E.; Parker, Clare E.; Romero, L. Michael; Mitchell, Mark A.

2015-01-01

The evaluation of hormonal responses to stress in reptiles relies on acquisition of baseline corticosterone concentrations; however, the stress associated with the restraint needed to collect the blood samples can affect the results. The purpose of this study was to determine a time limit for the collection of blood samples to evaluate baseline corticosterone, haematological and biochemical results in nesting (n = 11) and rehabilitating (n = 16) loggerhead sea turtles (Caretta caretta). Blood samples were collected from the dorsal cervical sinus of each turtle immediately after touching the animal (t0; 0–3 min) and 3 (t3; 3–6 min), 6 (t6; 6–9 min; nesting turtles only), 10 (t10; 10–13 min) and 30 min (t30; rehabilitating turtles only) after the initial hands-on time. Consistent between the rehabilitating and nesting turtles, there was a subtle yet significant increase in white blood cell counts over time. Despite the fact that white blood cell counts increased during the sampling period, there was no direct correlation between white blood cell count and corticosterone in the sampled turtles. In the nesting turtles, significant elevations in corticosterone were noted between t0 and t3 (P = 0.014) and between t0 and t6 (P = 0.022). Values at t10 were not significantly different from those at t0 (P = 0.102); however, there was a trend for the corticosterone values to continue to increase. These results suggest that sampling of nesting loggerhead sea turtles within 3 min of handling will provide baseline corticosterone concentrations in their natural environment. Significant elevations in corticosterone were also noted in the rehabilitating loggerhead sea turtles between t0 and t10 (P = 0.02) and between t0 and t30 of sampling (P = 0.0001). These results suggest that sampling of loggerhead sea turtles within 6 min of handling should provide baseline corticosterone concentrations in a rehabilitation setting. The delay in the corticosterone response noted in the rehabilitating turtles may be associated with the daily contact (visual or direct) they have with their human caretakers. PMID:27293688

Usage of Nest Materials by House Sparrow (Passer domesticus) Along an Urban to Rural Gradient in Coimbatore, India.

PubMed

Radhamany, Dhanya; Das, Karumampoyil Sakthidas Anoop; Azeez, Parappurath Abdul; Wen, Longying; Sreekala, Leelambika Krishnan

2016-08-01

The house sparrow (Passer domesticus) is a widely distributed bird species found throughout the world. Being a species which has close association with humans, they chiefly nest on man-made structures. Here we describe the materials used by the house sparrow for making nests along an urban to rural gradient. For the current study, we selected the Coimbatore to Anaikatty road (State Highway-164), a 27 km inter-state highway, which traverses along an urban core to rural outstretch of Coimbatore. Of the 30 nests observed, 15 nests were from the rural, 8 were from the suburban, and 7 were from the urban areas. The nests had two distinct layers, specifically the structural layer and the inner lining. In the current study, we identified 11 plant species, 2 types of animal matter, and 6 types of anthropogenic matter, including plastic pieces and fine rope. The amount of anthropogenic materials in the nest formation varied along the gradients. The usage of anthropogenic materials was high in urban areas (p<0.05) whereas it did not differ at the sub-urban regions (p>0.05). A gradual decrease in the usage of plant matter towards the urban area was noticed (p<0.05). This study explicitly documents the links between nest material usage along an urban to rural gradient, in a human associated bird.

Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot

USGS Publications Warehouse

Newmark, W.D.; Stanley, T.R.

2011-01-01

Ecologists have long hypothesized that fragmentation of tropical landscapes reduces avian nest success. However, this hypothesis has not been rigorously assessed because of the difficulty of finding large numbers of well-hidden nests in tropical forests. Here we report that in the East Usambara Mountains in Tanzania, which are part of the Eastern Arc Mountains, a global biodiversity hotspot, that daily nest survival rate and nest success for seven of eight common understory bird species that we examined over a single breeding season were significantly lower in fragmented than in continuous forest, with the odds of nest failure for these seven species ranging from 1.9 to 196.8 times higher in fragmented than continuous forest. Cup-shaped nests were particularly vulnerable in fragments. We then examined over six breeding seasons and 14 study sites in a multivariable survival analysis the influence of landscape structure and nest location on daily nest survival for 13 common species representing 1,272 nests and four nest types (plate, cup, dome, and pouch). Across species and nest types, area, distance of nest to edge, and nest height had a dominant influence on daily nest survival, with area being positively related to nest survival and distance of nest to edge and nest height being both positively and negatively associated with daily nest survival. Our results indicate that multiple environmental factors contribute to reduce nest survival within a tropical understory bird community in a fragmented landscape and that maintaining large continuous forest is important for enhancing nest survival for Afrotropical understory birds.

Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot.

PubMed

Newmark, William D; Stanley, Thomas R

2011-07-12

Ecologists have long hypothesized that fragmentation of tropical landscapes reduces avian nest success. However, this hypothesis has not been rigorously assessed because of the difficulty of finding large numbers of well-hidden nests in tropical forests. Here we report that in the East Usambara Mountains in Tanzania, which are part of the Eastern Arc Mountains, a global biodiversity hotspot, that daily nest survival rate and nest success for seven of eight common understory bird species that we examined over a single breeding season were significantly lower in fragmented than in continuous forest, with the odds of nest failure for these seven species ranging from 1.9 to 196.8 times higher in fragmented than continuous forest. Cup-shaped nests were particularly vulnerable in fragments. We then examined over six breeding seasons and 14 study sites in a multivariable survival analysis the influence of landscape structure and nest location on daily nest survival for 13 common species representing 1,272 nests and four nest types (plate, cup, dome, and pouch). Across species and nest types, area, distance of nest to edge, and nest height had a dominant influence on daily nest survival, with area being positively related to nest survival and distance of nest to edge and nest height being both positively and negatively associated with daily nest survival. Our results indicate that multiple environmental factors contribute to reduce nest survival within a tropical understory bird community in a fragmented landscape and that maintaining large continuous forest is important for enhancing nest survival for Afrotropical understory birds.

Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot

PubMed Central

Newmark, William D.; Stanley, Thomas R.

2011-01-01

Ecologists have long hypothesized that fragmentation of tropical landscapes reduces avian nest success. However, this hypothesis has not been rigorously assessed because of the difficulty of finding large numbers of well-hidden nests in tropical forests. Here we report that in the East Usambara Mountains in Tanzania, which are part of the Eastern Arc Mountains, a global biodiversity hotspot, that daily nest survival rate and nest success for seven of eight common understory bird species that we examined over a single breeding season were significantly lower in fragmented than in continuous forest, with the odds of nest failure for these seven species ranging from 1.9 to 196.8 times higher in fragmented than continuous forest. Cup-shaped nests were particularly vulnerable in fragments. We then examined over six breeding seasons and 14 study sites in a multivariable survival analysis the influence of landscape structure and nest location on daily nest survival for 13 common species representing 1,272 nests and four nest types (plate, cup, dome, and pouch). Across species and nest types, area, distance of nest to edge, and nest height had a dominant influence on daily nest survival, with area being positively related to nest survival and distance of nest to edge and nest height being both positively and negatively associated with daily nest survival. Our results indicate that multiple environmental factors contribute to reduce nest survival within a tropical understory bird community in a fragmented landscape and that maintaining large continuous forest is important for enhancing nest survival for Afrotropical understory birds. PMID:21709237

Simultaneous analysis and design

NASA Technical Reports Server (NTRS)

Haftka, R. T.

1984-01-01

Optimization techniques are increasingly being used for performing nonlinear structural analysis. The development of element by element (EBE) preconditioned conjugate gradient (CG) techniques is expected to extend this trend to linear analysis. Under these circumstances the structural design problem can be viewed as a nested optimization problem. There are computational benefits to treating this nested problem as a large single optimization problem. The response variables (such as displacements) and the structural parameters are all treated as design variables in a unified formulation which performs simultaneously the design and analysis. Two examples are used for demonstration. A seventy-two bar truss is optimized subject to linear stress constraints and a wing box structure is optimized subject to nonlinear collapse constraints. Both examples show substantial computational savings with the unified approach as compared to the traditional nested approach.

The effect of wind on the rate of heat loss from avian cup-shaped nests.

PubMed

Heenan, Caragh B; Seymour, Roger S

2012-01-01

Forced convection can significantly influence the heat loss from birds and their offspring but effects may be reduced by using sheltered micro-sites such as cavities or constructing nests. The structural and thermal properties of the nests of two species, the spiny-cheeked honeyeater (Acanthagenys rufogularis) and yellow-throated miner (Manorina flavigula), were measured in relation to three wind speeds. Nest dimensions differ between the two species, despite the similar body mass of the incubating adults, however nest conductance is comparable. As wind speed increases, so does the rate of heat loss from the nests of both species, and further still during incubation recesses. The significance of forced convection through the nest is a near-doubling in heat production required by the parent, even when incubating at relatively low wind speeds. This provides confirmation that selecting a sheltered nest site is important for avian reproductive success.

The Effect of Wind on the Rate of Heat Loss from Avian Cup-Shaped Nests

PubMed Central

Heenan, Caragh B.; Seymour, Roger S.

2012-01-01

Forced convection can significantly influence the heat loss from birds and their offspring but effects may be reduced by using sheltered micro-sites such as cavities or constructing nests. The structural and thermal properties of the nests of two species, the spiny-cheeked honeyeater (Acanthagenys rufogularis) and yellow-throated miner (Manorina flavigula), were measured in relation to three wind speeds. Nest dimensions differ between the two species, despite the similar body mass of the incubating adults, however nest conductance is comparable. As wind speed increases, so does the rate of heat loss from the nests of both species, and further still during incubation recesses. The significance of forced convection through the nest is a near-doubling in heat production required by the parent, even when incubating at relatively low wind speeds. This provides confirmation that selecting a sheltered nest site is important for avian reproductive success. PMID:22389689

Direct effects of cattle on grassland birds in Canada.

PubMed

Bleho, Barbara I; Koper, Nicola; Machtans, Craig S

2014-06-01

Effects of grazing on grassland birds are generally thought to be indirect, through alteration of vegetation structure; however, livestock can also affect nest survival directly through trampling and other disturbances (e.g., livestock-induced abandonment). We extracted data on nest fates from 18 grazing studies conducted in Canada. We used these data to assess rates of nest destruction by cattle among 9 ecoregions and between seasonal and rotational grazing systems. Overall, few nests were destroyed by cattle (average 1.5% of 9132 nests). Nest destruction was positively correlated with grazing pressure (i.e., stocking rate or grazing intensity), but nest survival was higher in more heavily grazed areas for some species. Because rates of destruction of grassland bird nests by cattle are low in Canada, management efforts to reduce such destruction may not be of ecological or economic value in Canada. © 2014 Society for Conservation Biology.

Nestedness of desert bat assemblages: species composition patterns in insular and terrestrial landscapes.

PubMed

Frick, Winifred F; Hayes, John P; Heady, Paul A

2009-01-01

Nested patterns of community composition exist when species at depauperate sites are subsets of those occurring at sites with more species. Nested subset analysis provides a framework for analyzing species occurrences to determine non-random patterns in community composition and potentially identify mechanisms that may shape faunal assemblages. We examined nested subset structure of desert bat assemblages on 20 islands in the southern Gulf of California and at 27 sites along the Baja California peninsula coast, the presumable source pool for the insular faunas. Nested structure was analyzed using a conservative null model that accounts for expected variation in species richness and species incidence across sites (fixed row and column totals). Associations of nestedness and island traits, such as size and isolation, as well as species traits related to mobility, were assessed to determine the potential role of differential extinction and immigration abilities as mechanisms of nestedness. Bat faunas were significantly nested in both the insular and terrestrial landscape and island size was significantly correlated with nested structure, such that species on smaller islands tended to be subsets of species on larger islands, suggesting that differential extinction vulnerabilities may be important in shaping insular bat faunas. The role of species mobility and immigration abilities is less clearly associated with nestedness in this system. Nestedness in the terrestrial landscape is likely due to stochastic processes related to random placement of individuals and this may also influence nested patterns on islands, but additional data on abundances will be necessary to distinguish among these potential mechanisms.

Genetic structure of Florida green turtle rookeries as indicated by mitochondrial DNA control region sequences

USGS Publications Warehouse

Shamblin, Brian M.; Bagley, Dean A.; Ehrhart, Llewellyn M.; Desjardin, Nicole A.; Martin, R. Erik; Hart, Kristen M.; Naro-Maciel, Eugenia; Rusenko, Kirt; Stiner, John C.; Sobel, Debra; Johnson, Chris; Wilmers, Thomas; Wright, Laura J.; Nairn, Campbell J.

2014-01-01

Green turtle (Chelonia mydas) nesting has increased dramatically in Florida over the past two decades, ranking the Florida nesting aggregation among the largest in the Greater Caribbean region. Individual beaches that comprise several hundred kilometers of Florida’s east coast and Keys support tens to thousands of nests annually. These beaches encompass natural to highly developed habitats, and the degree of demographic partitioning among rookeries was previously unresolved. We characterized the genetic structure of ten Florida rookeries from Cape Canaveral to the Dry Tortugas through analysis of 817 base pair mitochondrial DNA (mtDNA) control region sequences from 485 nesting turtles. Two common haplotypes, CM-A1.1 and CM-A3.1, accounted for 87 % of samples, and the haplotype frequencies were strongly partitioned by latitude along Florida’s Atlantic coast. Most genetic structure occurred between rookeries on either side of an apparent genetic break in the vicinity of the St. Lucie Inlet that separates Hutchinson Island and Jupiter Island, representing the finest scale at which mtDNA structure has been documented in marine turtle rookeries. Florida and Caribbean scale analyses of population structure support recognition of at least two management units: central eastern Florida and southern Florida. More thorough sampling and deeper sequencing are necessary to better characterize connectivity among Florida green turtle rookeries as well as between the Florida nesting aggregation and others in the Greater Caribbean region.

Grassland bird productivity in warm season grass fields in southwest Wisconsin

USGS Publications Warehouse

Byers, Carolyn M.; Ribic, Christine; Sample, David W.; Dadisman, John D.; Guttery, Michael

2017-01-01

Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agriculture's Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Grasshopper Sparrow (Ammodramus savannarum), and Henslow's Sparrow (A. henslowii), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslow's Sparrow nest density was highest 1 y post burn, and apparent Bobolink and Eastern Meadowlark nest densities were higher in post fire years one to three. Grasshopper Sparrow nest density was highest on sites with more diverse vegetation, specifically prairie forbs, and on sites with shorter less dense vegetation. Bobolink, Eastern Meadowlark, and Henslow's Sparrow apparent nest densities were higher on sites with deeper litter; litter was the vegetative component that was most affected by spring burns. Overall nest success was 0.487 for Bobolink (22 d nesting period), 0.478 for Eastern Meadowlark (25 d nesting period), 0.507 for Grasshopper Sparrow (22 d nesting period), and 0.151 for Henslow's Sparrow (21 d nesting period). The major nest predators were grassland-associated species: thirteen-lined ground squirrel (Ictidomys tridecemlineatus), striped skunk (Mephitis mephitis), milk snake (Lampropeltis triangulum), American badger (Taxidea taxus), and western fox snake (Elaphe vulpina). Overall depredation rate was not affected by the number of years since the site had been burned. The diversity of vegetation on warm season CRP fields created by management using fire provides a continuum of structure for obligate grassland birds to use for breeding and habitat for a diversity of nest predators.

A Methodological Review of Statistical Methods for Handling Multilevel Non-Nested Longitudinal Data in Educational Research

ERIC Educational Resources Information Center

Sun, Shuyan; Pan, Wei

2014-01-01

As applications of multilevel modelling in educational research increase, researchers realize that multilevel data collected in many educational settings are often not purely nested. The most common multilevel non-nested data structure is one that involves student mobility in longitudinal studies. This article provides a methodological review of…

Evaluation of Military Range Berm Effectiveness in Protecting Red-cockaded Woodpecker Foraging and Nesting Habitat

DTIC Science & Technology

2011-04-01

Benning – Malone 5 Malone 5 is an unbermed SA machine gun (firing 7.62 mm or smaller caliber rounds) range with elevated firing and target boxes (~1...plots, not originally allocated. Fort Stewart – Kilo The Kilo range on Fort Stewart is an unbermed SA machine gun (firing 7.62 mm or smaller...is a bermed SA machine gun (firing 7.62 mm or smaller caliber rounds) range with elevated firing boxes and targets (~1-m high; Figures 6 and 7). The

Nestly--a framework for running software with nested parameter choices and aggregating results.

PubMed

McCoy, Connor O; Gallagher, Aaron; Hoffman, Noah G; Matsen, Frederick A

2013-02-01

The execution of a software application or pipeline using various combinations of parameters and inputs is a common task in bioinformatics. In the absence of a specialized tool to organize, streamline and formalize this process, scientists must write frequently complex scripts to perform these tasks. We present nestly, a Python package to facilitate running tools with nested combinations of parameters and inputs. nestly provides three components. First, a module to build nested directory structures corresponding to choices of parameters. Second, the nestrun script to run a given command using each set of parameter choices. Third, the nestagg script to aggregate results of the individual runs into a CSV file, as well as support for more complex aggregation. We also include a module for easily specifying nested dependencies for the SCons build tool, enabling incremental builds. Source, documentation and tutorial examples are available at http://github.com/fhcrc/nestly. nestly can be installed from the Python Package Index via pip; it is open source (MIT license).

A comparison of burn season effects on nesting birds in North Dakota mixed-grass prairie

USGS Publications Warehouse

Higgins, K.F.

1986-01-01

During 1982-1985, the effects of single spring and fall burn treatments on ground nesting birds and residual cover were studied on five paired areas of native mixed-grass prairie in northwestern Stutsman County, ND. Annually, visual obstruction readings to index the height-density of residual cover were taken once and nest searches were made four times on each area. Residual nesting cover on fall burn plots averaged taller and denser than on spring burn plots during post-fire growing years 2-4. A total of 259 duck nests and 63 nests of non-passerine birds were found during the four years. Duck nesting success was significantly greater (P < 0.05) in fall burn plots than in spring burn plots for all species and years combined. Too few nests of other bird species were found for valid comparisons. Results suggest that vegetation structure and duck nesting response to spring and fall burns became similar again by the third post-fire growing season.

Habitat selection responses of parents to offspring predation risk: An experimental test

USGS Publications Warehouse

Fontaine, J.J.; Martin, T.E.

2006-01-01

The ability of nest predation to influence habitat settlement decisions in birds is widely debated, despite its importance in limiting fitness. Here, we experimentally manipulated nest predation risk across a landscape and asked the question, do migratory birds assess and respond to variation in nest predation risk when choosing breeding habitats? We examined habitat preference by quantifying the density and settlement date of eight species of migratory passerines breeding in areas with and without intact nest predator communities. We found consistently more individuals nesting in areas with reduced nest predation than in areas with intact predator assemblages, although predation risk had no influence on settlement or breeding phenology. Additionally, those individuals occupying safer nesting habitats exhibited increased singing activity. These findings support a causal relationship between habitat choice and nest predation risk and suggest the importance of nest predation risk in shaping avian community structure and breeding activity. ?? 2006 by The University of Chicago. All rights reserved.

Phenotypic integration in an extended phenotype: among-individual variation in nest-building traits of the alfalfa leafcutting bee (Megachile rotundata).

PubMed

Royauté, Raphaël; Wilson, Elisabeth S; Helm, Bryan R; Mallinger, Rachel E; Prasifka, Jarrad; Greenlee, Kendra J; Bowsher, Julia H

2018-03-02

Structures such as nests and burrows are an essential component of many organisms' life-cycle and require a complex sequence of behaviours. Because behaviours can vary consistently among individuals and be correlated with one another, we hypothesized that these structures would (1) show evidence of among-individual variation, (2) be organized into distinct functional modules and (3) show evidence of trade-offs among functional modules due to limits on energy budgets. We tested these hypotheses using the alfalfa leafcutting bee, Megachile rotundata, a solitary bee and important crop pollinator. Megachile rotundata constructs complex nests by gathering leaf materials to form a linear series of cells in pre-existing cavities. In this study, we examined variation in the following nest construction traits: reproduction (number of cells per nest and nest length), nest protection (cap length and number of leaves per cap), cell construction (cell size and number of leaves per cell) and cell provisioning (cell mass) from 60 nests. We found a general decline in investment in cell construction and provisioning with each new cell built. In addition, we found evidence for both repeatability and plasticity in cell provisioning with little evidence for trade-offs among traits. Instead, most traits were positively, albeit weakly, correlated (r ~ 0.15), and traits were loosely organized into covarying modules. Our results show that individual differences in nest construction are detectable at a level similar to that of other behavioural traits and that these traits are only weakly integrated. This suggests that nest components are capable of independent evolutionary trajectories. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

Origin and Alteration of Organic Matter in Termite Mounds from Different Feeding Guilds of the Amazon Rainforests

PubMed Central

Siebers, Nina; Martius, Christopher; Eckhardt, Kai-Uwe; Garcia, Marcos V. B.; Leinweber, Peter; Amelung, Wulf

2015-01-01

The impact of termites on nutrient cycling and tropical soil formation depends on their feeding habits and related material transformation. The identification of food sources, however, is difficult, because they are variable and changed by termite activity and nest construction. Here, we related the sources and alteration of organic matter in nests from seven different termite genera and feeding habits in the Terra Firme rainforests to the properties of potential food sources soil, wood, and microepiphytes. Chemical analyses comprised isotopic composition of C and N, cellulosic (CPS), non-cellulosic (NCPS), and N-containing saccharides, and molecular composition screening using pyrolysis-field ionization mass spectrometry (Py-FIMS). The isotopic analysis revealed higher soil δ13C (-27.4‰) and δ15N (6.6‰) values in nests of wood feeding Nasutitermes and Cornitermes than in wood samples (δ13C = -29.1‰, δ15N = 3.4‰), reflecting stable-isotope enrichment with organic matter alterations during or after nest construction. This result was confirmed by elevated NCPS:CPS ratios, indicating a preferential cellulose decomposition in the nests. High portions of muramic acid (MurAc) pointed to the participation of bacteria in the transformation processes. Non-metric multidimensional scaling (NMDS) revealed increasing geophagy in the sequence Termes < Embiratermes < Anoplotermes and increasing xylophagy for Cornitermes < Nasutitermes, and that the nest material of Constrictotermes was similar to the microepiphytes sample, confirming the report that Constrictotermes belongs to the microepiphyte-feeders. We therewith document that nest chemistry of rainforest termites shows variations and evidence of modification by microbial processes, but nevertheless it primarily reflects the trophic niches of the constructors. PMID:25909987

Origin and alteration of organic matter in termite mounds from different feeding guilds of the Amazon rainforests.

PubMed

Siebers, Nina; Martius, Christopher; Eckhardt, Kai-Uwe; Garcia, Marcos V B; Leinweber, Peter; Amelung, Wulf

2015-01-01

The impact of termites on nutrient cycling and tropical soil formation depends on their feeding habits and related material transformation. The identification of food sources, however, is difficult, because they are variable and changed by termite activity and nest construction. Here, we related the sources and alteration of organic matter in nests from seven different termite genera and feeding habits in the Terra Firme rainforests to the properties of potential food sources soil, wood, and microepiphytes. Chemical analyses comprised isotopic composition of C and N, cellulosic (CPS), non-cellulosic (NCPS), and N-containing saccharides, and molecular composition screening using pyrolysis-field ionization mass spectrometry (Py-FIMS). The isotopic analysis revealed higher soil δ13C (-27.4‰) and δ15N (6.6‰) values in nests of wood feeding Nasutitermes and Cornitermes than in wood samples (δ13C = -29.1‰, δ15N = 3.4‰), reflecting stable-isotope enrichment with organic matter alterations during or after nest construction. This result was confirmed by elevated NCPS:CPS ratios, indicating a preferential cellulose decomposition in the nests. High portions of muramic acid (MurAc) pointed to the participation of bacteria in the transformation processes. Non-metric multidimensional scaling (MDS) revealed increasing geophagy in the sequence Termes < Embiratermes < Anoplotermes and increasing xylophagy for Cornitermes < Nasutitermes., and that the nest material of Constrictotermes was similar to the microepiphytes sample, confirming the report that Constrictotermes belongs to the microepiphyte-feeders. We therewith document that nest chemistry of rainforest termites shows variations and evidence of modification by microbial processes, but nevertheless it primarily reflects the trophic niches of the constructors.

Nestedness in assemblages of helminth parasites of bats: a function of geography, environment, or host nestedness?

PubMed

Warburton, Elizabeth M; Van Der Mescht, Luther; Khokhlova, Irina S; Krasnov, Boris R; Vonhof, Maarten J

2018-05-01

Nested subsets occur in ecological communities when species-poor communities are subsets of larger, species-rich communities. Understanding this pattern can help elucidate species colonization abilities, extinction risks, and general structuring of biological communities. Here, we evaluate nestedness in a poorly studied host-parasite system, bats and their helminths, across the Japanese archipelago and within its different bioclimatic regions. We hypothesized that (1) if helminth communities are nested across geographic sites at the level of the archipelago, then broad-scale processes, like colonization-extinction dynamics, mainly structure parasite assemblages; (2) if helminth communities are nested across geographic sites at the level of the bioclimatic region, then fine-scale environmental variation plays a significant role in species nestedness; (3) if helminth community nestedness mirrors host species nestedness, then communities are nested because the habitats they occupy are nested; and (4) if nestedness does not occur or if it is not correlated with any geographical or host data, then passive sampling could be responsible for the patterns of parasite assemblage in our sample. We found that helminth communities were nested across host species throughout the archipelago but, when considering each bioclimatic region, helminths in only one region were significantly more nested than the null model. Helminth communities were also nested across sites within all four bioclimatic regions. These results suggest that helminths form nested subsets across the archipelago due to broad-scale processes that reflect the overall lineages of their mammalian hosts; however, at the regional scale, environmental processes related to nestedness of their habitats drive parasite community nestedness.

Variation in fire regimes of the Rocky Mountains: Implications for avian communities and fire management

USGS Publications Warehouse

Saab, Victoria A.; Powell, Hugo D.W.; Kotliar, Natasha B.; Newlon, Karen R.; Saab, Victoria A.; Powell, Hugo D.W.

2005-01-01

Information about avian responses to fire in the U.S. Rocky Mountains is based solely on studies of crown fires. However, fire management in this region is based primarily on studies of low-elevation ponderosa pine (Pinus ponderosa) forests maintained largely by frequent understory fires. In contrast to both of these trends, most Rocky Mountain forests are subject to mixed severity fire regimes. As a result, our knowledge of bird responses to fire in the region is incomplete and skewed toward ponderosa pine forests. Research in recent large wildfires across the Rocky Mountains indicates that large burns support diverse avifauna. In the absence of controlled studies of bird responses to fire, we compared reproductive success for six cavity-nesting species using results from studies in burned and unburned habitats. Birds in ponderosa pine forests burned by stand-replacement fire tended to have higher nest success than individuals of the same species in unburned habitats, but unburned areas are needed to serve species dependent upon live woody vegetation, especially foliage gleaners. Over the last century, fire suppression, livestock grazing, and logging altered the structure and composition of many low-elevation forests, leading to larger and more severe burns. In higher elevation forests, changes have been less marked. Traditional low-severity prescribed fire is not likely to replicate historical conditions in these mixed or high-severity fire regimes, which include many mixed coniferous forests and all lodgepole pine (Pinus contorta) and spruce-fi r (Picea-Abies) forests. We suggest four research priorities: (1) the effects of fire severity and patch size on species’ responses to fire, (2) the possibility that postfire forests are ephemeral sources for some bird species, (3) the effect of salvage logging prescriptions on bird communities, and (4) experiments that illustrate bird responses to prescribed fire and other forest restoration methods. This research is urgent if we are to develop fire management strategies that reduce fire risk and maintain habitat for avifauna and other wildlife of the Rocky Mountains.

Variation in fire regimes of the rocky mountains: Implications for avian communities and fire management

USGS Publications Warehouse

Saab, V.A.; Powell, Hugo D.W.; Kotliar, N.B.; Newlon, K.R.

2005-01-01

Information about avian responses to fire in the U.S. Rocky Mountains is based solely on studies of crown fires. However, fire management in this region is based primarily on studies of low-elevation ponderosa pine (Pinus ponderosa) forests maintained largely by frequent understory fires. In contrast to both of these trends, most Rocky Mountain forests are subject to mixed severity fire regimes. As a result, our knowledge of bird responses to fire in the region is incomplete and skewed toward ponderosa pine forests. Research in recent large wildfires across the Rocky Mountains indicates that large burns support diverse avifauna. In the absence of controlled studies of bird responses to fire, we compared reproductive success for six cavity-nesting species using results from studies in burned and unburned habitats. Birds in ponderosa pine forests burned by stand-replacement fire tended to have higher nest success than individuals of the same species in unburned habitats, but unburned areas are needed to serve species dependent upon live woody vegetation, especially foliage gleaners. Over the last century, fire suppression, livestock grazing, and logging altered the structure and composition of many low-elevation forests, leading to larger and more severe burns. In higher elevation forests, changes have been less marked. Traditional low-severity prescribed fire is not likely to replicate historical conditions in these mixed or high-severity fire regimes, which include many mixed coniferous forests and all lodgepole pine (Pinus contorta) and spruce-fir (Picea-Abies) forests. We suggest four research priorities: (1) the effects of fire severity and patch size on species' responses to fire, (2) the possibility that postfire forests are ephemeral sources for some bird species, (3) the effect of salvage logging prescriptions on bird communities, and (4) experiments that illustrate bird responses to prescribed fire and other forest restoration methods. This research is urgent if we are to develop fire management strategies that reduce fire risk and maintain habitat for avifauna and other wildlife of the Rocky Mountains.

First description of the nest, eggs, and breeding behavior of the Mérida Tapaculo (Scytalopus meridanus)

USGS Publications Warehouse

Decker, Karie L.; Niklison, Alina M.; Martin, Thomas E.

2007-01-01

We provide the first description of the nest, eggs, and breeding behavior of the Mérida Tapaculo (Scytalopus meridanus). Data are from one pair in the moist cloud forest of Yacambu National Park, Venezuela during April–May 2004. Two nests, constructed by the same pair, were globular in structure and consisted of mossy material placed in a rock crevice of a muddy rock wall. The eggs were cream colored with an average mass of 4.19 g. Clutch sizes were one in the first nest and two in the second. The species showed bi-parental care in nest building and incubation. Nest attentiveness (percent time spent on the nest incubating) averaged 83.4 ± 14% (SD). Average on and off bouts were 33.24 and 6.34 min, respectively.

Statistical self-similarity of width function maxima with implications to floods

USGS Publications Warehouse

Veitzer, S.A.; Gupta, V.K.

2001-01-01

Recently a new theory of random self-similar river networks, called the RSN model, was introduced to explain empirical observations regarding the scaling properties of distributions of various topologic and geometric variables in natural basins. The RSN model predicts that such variables exhibit statistical simple scaling, when indexed by Horton-Strahler order. The average side tributary structure of RSN networks also exhibits Tokunaga-type self-similarity which is widely observed in nature. We examine the scaling structure of distributions of the maximum of the width function for RSNs for nested, complete Strahler basins by performing ensemble simulations. The maximum of the width function exhibits distributional simple scaling, when indexed by Horton-Strahler order, for both RSNs and natural river networks extracted from digital elevation models (DEMs). We also test a powerlaw relationship between Horton ratios for the maximum of the width function and drainage areas. These results represent first steps in formulating a comprehensive physical statistical theory of floods at multiple space-time scales for RSNs as discrete hierarchical branching structures. ?? 2001 Published by Elsevier Science Ltd.

Phenotypic integration in an extended phenotype: among-individual variation in nest-building traits of the alfalfa leafcutting bee (Megachile rotundata)

USDA-ARS?s Scientific Manuscript database

Structures such as nests and burrows are an essential component of many organisms’ life-cycle and requires a complex sequence of behaviors. Because behaviors can vary consistently among individuals and be correlated with one another, we hypothesized that these structures would 1) show evidence of am...

Association of weather and nest-site structure with reproductive success in California spotted owls

Treesearch

Malcolm North; George Steger; Renee Denton; Gary Eberlein; Tom Munton; Ken Johnson

2000-01-01

Although the spotted owl (Strix occidentalis) has been intensively studied, factors influencing its reproduction are not well understood. We examined a 9-year demographic study of 51-86 pairs of the California spotted owl (S. o. occidentalis), weather conditions, and forest structure at nest sites in oak (Quercus sp.) woodland and...

Coupling contaminants with demography: Effects of lead and selenium in Pacific common eiders

USGS Publications Warehouse

Wilson, H.M.; Flint, Paul L.; Powell, A.N.

2007-01-01

We coupled intensive population monitoring with collection of blood samples from 383 nesting Pacific common eiders (Somateria mollisima v-nigrum) at two locations in Alaska (USA) from 2002 to 2004. We investigated annual, geographic, and within-season variation in blood concentrations of lead and selenium; compared exposure patterns with sympatrically nesting spectacled eiders (Somateria fischeri); and examined relationships with clutch size, egg viability, probability of hatching, and apparent survival of adult females. Lead concentrations were elevated in 3.6% of females, and all individuals exhibited elevated selenium, most (81%) at concentrations associated with death in captive waterfowl. Blood lead and selenium concentrations varied both within and among site-years and were lower than those of spectacled eiders. During incubation, blood lead concentrations in females increased significantly (possibly via re-release of stored lead from bone), whereas selenium concentrations decreased (likely because of natural excretion). Probability of a nest containing at least one nonviable egg was positively related to blood selenium in hens, but adverse effects in other life-history variables were not supported. Although reproduction appeared to be sensitive to selenium toxicity, our data suggest that high rates of nonviability are unlikely in this population and that selenium-related reductions to clutch size would be inconsequential at the scale of overall population dynamics. We conclude that Pacific common eiders and other wild marine birds likely have higher selenium tolerances than freshwater species and that interspecific differences in exposure levels may reflect differences in reproductive strategies.

Integration of coastal inundation modeling from storm tides to individual waves

NASA Astrophysics Data System (ADS)

Li, Ning; Roeber, Volker; Yamazaki, Yoshiki; Heitmann, Troy W.; Bai, Yefei; Cheung, Kwok Fai

2014-11-01

Modeling of storm-induced coastal inundation has primarily focused on the surge generated by atmospheric pressure and surface winds with phase-averaged effects of the waves as setup. Through an interoperable model package, we investigate the role of phase-resolving wave processes in simulation of coastal flood hazards. A spectral ocean wave model describes generation and propagation of storm waves from deep to intermediate water, while a non-hydrostatic storm-tide model has the option to couple with a spectral coastal wave model for computation of phase-averaged processes in a near-shore region. The ocean wave and storm-tide models can alternatively provide the wave spectrum and the surface elevation as the boundary and initial conditions for a nested Boussinesq model. Additional surface-gradient terms in the Boussinesq equations maintain the quasi-steady, non-uniform storm tide for modeling of phase-resolving surf and swash-zone processes as well as combined tide, surge, and wave inundation. The two nesting schemes are demonstrated through a case study of Hurricane Iniki, which made landfall on the Hawaiian Island of Kauai in 1992. With input from a parametric hurricane model and global reanalysis and tidal datasets, the two approaches produce comparable significant wave heights and phase-averaged surface elevations in the surf zone. The nesting of the Boussinesq model provides a seamless approach to augment the inundation due to the individual waves in matching the recorded debris line along the coast.

Representing nested semantic information in a linear string of text using XML.

PubMed

Krauthammer, Michael; Johnson, Stephen B; Hripcsak, George; Campbell, David A; Friedman, Carol

2002-01-01

XML has been widely adopted as an important data interchange language. The structure of XML enables sharing of data elements with variable degrees of nesting as long as the elements are grouped in a strict tree-like fashion. This requirement potentially restricts the usefulness of XML for marking up written text, which often includes features that do not properly nest within other features. We encountered this problem while marking up medical text with structured semantic information from a Natural Language Processor. Traditional approaches to this problem separate the structured information from the actual text mark up. This paper introduces an alternative solution, which tightly integrates the semantic structure with the text. The resulting XML markup preserves the linearity of the medical texts and can therefore be easily expanded with additional types of information.

Representing nested semantic information in a linear string of text using XML.

PubMed Central

Krauthammer, Michael; Johnson, Stephen B.; Hripcsak, George; Campbell, David A.; Friedman, Carol

2002-01-01

XML has been widely adopted as an important data interchange language. The structure of XML enables sharing of data elements with variable degrees of nesting as long as the elements are grouped in a strict tree-like fashion. This requirement potentially restricts the usefulness of XML for marking up written text, which often includes features that do not properly nest within other features. We encountered this problem while marking up medical text with structured semantic information from a Natural Language Processor. Traditional approaches to this problem separate the structured information from the actual text mark up. This paper introduces an alternative solution, which tightly integrates the semantic structure with the text. The resulting XML markup preserves the linearity of the medical texts and can therefore be easily expanded with additional types of information. PMID:12463856

Semi-arid grassland bird responses to patch-burn grazing and drought

USGS Publications Warehouse

Skagen, Susan K.; Augustine, David J.; Derner, Justin D.

2018-01-01

As grassland birds of central North America experience steep population declines with changes in land use, management of remaining tracts becomes increasingly important for population viability. The integrated use of fire and grazing may enhance vegetation heterogeneity and diversity in breeding birds, but the subsequent effects on reproduction are unknown. We examined the influence of patch-burn grazing management in shortgrass steppe in eastern Colorado on habitat use and reproductive success of 3 grassland bird species, horned lark (Eremophila alpestris), lark bunting (Calamospiza melanocorys), and McCown’s longspur (Rhynchophanes mccownii), at several spatial scales during 2011 and 2012. Although no simple direct relationship to patch-burn grazing treatment existed, habitat selection depended on precipitation- and management-induced vegetation conditions and spatial scale. All species selected taller-than-expected vegetation at the nest site, whereas at the territory scale, horned larks and McCown’s longspurs selected areas with low vegetation height and sparse cover of tall plants (taller than the dominant shortgrasses). Buntings nested primarily in unburned grassland under average rainfall. Larks and longspurs shifted activity from patch burns during average precipitation (2011) to unburned pastures during drought (2012). Daily survival rate (DSR) of nests varied with time in season, species, weather, and vegetation structure. Daily survival rate of McCown’s longspur nests did not vary with foliar cover of relatively tall vegetation at the nest under average precipitation but declined with increasing cover during drought. At the 200-m scale, increasing cover of shortgrasses, rather than taller plant species, improved DSR of larks and longspurs. These birds experience tradeoffs in the selection of habitat at different spatial scales: tall structure at nests may reduce visual detection by predators and provide protection from sun, wind, and rain, yet taller structure surrounding territories may host nest predators. Patch-burn grazing management in combination with other strategies that retain taller-structured vegetation may help sustain a diversity of breeding habitats for shortgrass birds under varying weather conditions.

Influence of restoration and succession on bottomland hardwood hydrology

Treesearch

Randy K. Kolka; J. H. Singer; C. R. Coppock; W. P. Casey; C. C. Trettin

2000-01-01

The hydrologic pathways of four bottomland hardwood wetland sites were investigated with transects consisting of nests of shallow wells and piezometers. Sites included a disturbed but recently restored system, two disturbed systems that are recovering naturally and a relatively undisturbed reference site. Water table elevations in both uplands and bottomlands were...

Effect of nest characteristics on thermal properties, clutch size, and reproductive performance for an open-cup nesting songbird

Treesearch

Michael E. Akresh; Daniel R. Ardia; David I. King

2017-01-01

Maintaining avian eggs and young at optimum temperatures for development can increase hatching success and nestling condition, but this maintenance requires parental energetic demands. Bird nests, which often provide a structure to safely hold the eggs and nestlings and protect them from predators, can additionally be designed to help maintain eggs' optimum...

Nesting characteristics of mourning doves in central New Mexico: Response to riparian forest change

Treesearch

D. Max Smith; Deborah M. Finch; David L. Hawksworth

2012-01-01

Riparian forests of the American Southwest are especially prone to changes in composition and structure due to natural and anthropogenic factors. To determine how breeding mourning doves (Zenaida macroura) respond to these changes, we examined nest site use and nest survival in control plots, fuel reduction plots before and after mechanical thinning, and post-wildfire...

34. THE CROW'S NEST. IN THE EARLY YEARS OF THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

34. THE CROW'S NEST. IN THE EARLY YEARS OF THE INN MUSICIANS SAT AND PLAYED FOR THE GUESTS IN THE LOBBY BELOW. THE EARTHQUAKE IN 1959 CAUSED SOME STRUCTURAL DAMAGE AND NOW THE CROW'S NEST IS NOT ACCESSIBLE TO THE PUBLIC. - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

Subarctic, alpine nesting by Bairds Sandpipers Calidris bairdii

USGS Publications Warehouse

Gill, Robert E.; Tomkovich, Pavel S.

2004-01-01

Baird's Sandpipers Calidris bairdii were found nesting in alpine habitat in southwestern Alaska (60°48'N, 154°00'W), almost 250 km from the nearest known breeding site, and studied over three consecutive seasons, 1997-1999. The first birds arrived during the second week of May each spring with peak numbers recorded the third week of May. Most nests and newly hatched broods were found on sparsely vegetated dwarf shrub-lichen mat tundra on level or gently sloping areas throughout the alpine zone between 980 and 1400 m above sea level. Most eggs hatched during the third week of June and independent young were noted during the second and third weeks of July. Both parents initially tended broods, but only the male remained after chicks were about four days of age. During early brood-rearing, adults began to move chicks, often to higher elevations and over distances of several hundred metres. Throughout the area the density of nesting birds was about 0.2 pairs/km 2 with up to 0.9 pairs/km 2 found on southerly exposures of the north study slope. A summary of available information revealed the global nesting distribution of bairdii to be strongly associated with disturbed landscapes, especially montane areas affected by glaciation, suggesting the breeding range is likely to be much more extensive than currently known, especially in areas of Alaska, the Yukon, and possibly Chukotka.

Changes in productivity and contaminants in bald eagles nesting along the lower Columbia River, USA

USGS Publications Warehouse

Buck, J.A.; Anthony, R.G.; Schuler, C.A.; Isaacs, F.B.; Tillitt, D.E.

2005-01-01

Previous studies documented poor productivity of bald eagles (Haliaeetus leucocephalus) in the lower Columbia River (LCR), USA, and elevated p,p???-dichlorodiphenyldichloroethylene (DDE), polychlorinated biphenyls (PCBs), dioxins, and furans in eagle eggs. From 1994 to 1995, we collected partially incubated eggs at 19 of 43 occupied territories along the LCR and compared productivity and egg contaminants to values obtained in the mid-1980s. We found higher productivity at new nesting sites along the river, yet productivity at 23 older breeding territories remained low and was not different (p = 0.713) between studies. Eggshell thickness at older territories had not improved (p = 0.404), and eggshells averaged 11% thinner than shells measured before dichlorodiphenyltrichloroethane use. Decreases in DDE (p = 0.022) and total PCBs (p = 0.0004) in eggs from older breeding areas occurred between study periods. Productivity was not correlated to contaminants, but DDE, PCBs, and dioxin-like chemicals exceeded estimated no-effect values. Some dioxin-like contaminants in eggs were correlated to nest location, with highest concentrations occurring toward the river's mouth where productivity was lowest. Although total productivity increased due to the success of new nesting pairs in the region, egg contaminants remain high enough to impair reproduction at older territories and, over time, may alter productivity of new pairs nesting near the river's mouth. ?? 2005 SETAC.

Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests

PubMed Central

Trottier-Paquet, Myriam; Bêty, Joël; Lamarre, Vincent; Lecomte, Nicolas

2016-01-01

Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica) defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter “conspicuous behaviour”), as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada) in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs. PMID:27602257

Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests.

PubMed

Giroux, Marie-Andrée; Trottier-Paquet, Myriam; Bêty, Joël; Lamarre, Vincent; Lecomte, Nicolas

2016-01-01

Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica) defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter "conspicuous behaviour"), as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada) in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs.

Nest site characteristics, nesting movements, and lack of long-term nest site fidelity in Agassiz's desert tortoises at a wind energy facility in southern California

USGS Publications Warehouse

Lovich, Jeffrey E.; Agha, Mickey; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Bjurlin, Curtis; Ennen, Joshua R.; Arundel, Terry R.; Austin, Meaghan

2014-01-01

Nest site selection has important consequences for maternal and offspring survival and fitness. Females of some species return to the same nesting areas year after year. We studied nest site characteristics, fidelity, and daily pre-nesting movements in a population of Agassiz’s desert tortoises (Gopherus agassizii) at a wind energy facility in southern California during two field seasons separated by over a decade. No females returned to the same exact nest site within or between years but several nested in the same general area. However, distances between first and second clutches within a year (2000) were not significantly different from distances between nests among years (2000 and 2011) for a small sample of females, suggesting some degree of fidelity within their normal activity areas. Environmental attributes of nest sites did not differ significantly among females but did among years due largely to changes in perennial plant structure as a result of multiple fires. Daily pre-nesting distances moved by females decreased consistently from the time shelled eggs were first visible in X-radiographs until oviposition, again suggesting some degree of nest site selection. Tortoises appear to select nest sites that are within their long-term activity areas, inside the climate-moderated confines of one of their self-constructed burrows, and specifically, at a depth in the burrow that minimizes exposure of eggs and embryos to lethal incubation temperatures. Nesting in “climate-controlled” burrows and nest guarding by females relaxes some of the constraints that drive nest site selection in other oviparous species.

Variation in the structure of bird nests between northern Manitoba and southeastern Ontario.

PubMed

Crossman, Carla A; Rohwer, Vanya G; Martin, Paul R

2011-04-28

Traits that converge in appearance under similar environmental conditions among phylogenetically independent lineages are thought to represent adaptations to local environments. We tested for convergence in nest morphology and composition of birds breeding in two ecologically different locations in Canada: Churchill in northern Manitoba and Elgin in southeastern Ontario. We examined nests from four families of passerine birds (Turdidae: Turdus, Parulidae: Dendroica, Emberizidae: Passerculus and Fringillidae: Carduelis) where closely related populations or species breed in both locations. Nests of American Robins, Yellow Warblers, and Carduelis finches had heavier nest masses, and tended to have thicker nest-walls, in northern Manitoba compared with conspecifics or congenerics breeding in southeastern Ontario. Together, all species showed evidence for wider internal and external nest-cup diameters in northern Manitoba, while individual species showed varying patterns for internal nest-cup and external nest depths. American Robins, Yellow Warblers, and Carduelis finches in northern Manitoba achieved heavier nest masses in different ways. American Robins increased all materials in similar proportions, and Yellow Warblers and Common Redpolls used greater amounts of select materials. While changes in nest composition vary uniquely for each species, the pattern of larger nests in northern Manitoba compared to southeastern Ontario in three of our four phylogenetically-independent comparisons suggests that birds are adapting to similar selective pressures between locations.

Proximity to a high traffic road: glucocorticoid and life history consequences for nestling white-crowned sparrows.

PubMed

Crino, O L; Van Oorschot, B Klaassen; Johnson, E E; Malisch, J L; Breuner, C W

2011-09-01

Roads have been associated with decreased reproductive success and biodiversity in avian communities and increased physiological stress in adult birds. Alternatively, roads may also increase food availability and reduce predator pressure. Previous studies have focused on adult birds, but nestlings may also be susceptible to the detrimental impacts of roads. We examined the effects of proximity to a road on nestling glucocorticoid activity and growth in the mountain white-crowned sparrow (Zonotrichia leucophrys oriantha). Additionally, we examined several possible indirect factors that may influence nestling corticosterone (CORT) activity secretion in relation to roads. These indirect effects include parental CORT activity, nest-site characteristics, and parental provisioning. And finally, we assessed possible fitness consequences of roads through measures of fledging success. Nestlings near roads had increased CORT activity, elevated at both baseline and stress-induced levels. Surprisingly, these nestlings were also bigger. Generally, greater corticosterone activity is associated with reduced growth. However, the hypothalamic-pituitary-adrenal axis matures through the nestling period (as nestlings get larger, HPA-activation is greater). Although much of the variance in CORT responses was explained by body size, nestling CORT responses were higher close to roads after controlling for developmental differences. Indirect effects of roads may be mediated through paternal care. Nestling CORT responses were correlated with paternal CORT responses and paternal provisioning increased near roads. Hence, nestlings near roads may be larger due to increased paternal attentiveness. And finally, nest predation was higher for nests close to the road. Roads have apparent costs for white-crowned sparrow nestlings--increased predation, and apparent benefits--increased size. The elevation in CORT activity seems to reflect both increased size (benefit) and elevation due to road proximity (cost). Whether or not roads are good or bad for nestlings remains equivocal. However, it is clear that roads affect nestlings; how or if these effects influence adult survival or reproduction remains to be elucidated. Copyright © 2011 Elsevier Inc. All rights reserved.

Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

PubMed

Reynolds, Michelle H; Courtot, Karen N; Berkowitz, Paul; Storlazzi, Curt D; Moore, Janet; Flint, Elizabeth

2015-01-01

More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels.

Will the effects of sea-level rise create ecological traps for Pacific Island seabirds?

USGS Publications Warehouse

Reynolds, Michelle H.; Courtot, Karen; Berkowitz, Paul; Storlazzi, Curt; Moore, Janet; Flint, Elizabeth

2015-01-01

More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels.

Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

PubMed Central

Reynolds, Michelle H.; Courtot, Karen N.; Berkowitz, Paul; Storlazzi, Curt D.; Moore, Janet; Flint, Elizabeth

2015-01-01

More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels. PMID:26398209

Association between nighttime artificial light pollution and sea turtle nest density along Florida coast: A geospatial study using VIIRS remote sensing data.

PubMed

Hu, Zhiyong; Hu, Hongda; Huang, Yuxia

2018-08-01

Artificial lighting at night has becoming a new type of pollution posing an important anthropogenic environmental pressure on organisms. The objective of this research was to examine the potential association between nighttime artificial light pollution and nest densities of the three main sea turtle species along Florida beaches, including green turtles, loggerheads, and leatherbacks. Sea turtle survey data was obtained from the "Florida Statewide Nesting Beach Survey program". We used the new generation of satellite sensor "Visible Infrared Imaging Radiometer Suite (VIIRS)" (version 1 D/N Band) nighttime annual average radiance composite image data. We defined light pollution as artificial light brightness greater than 10% of the natural sky brightness above 45° of elevation (>1.14 × 10 -11 Wm -2 sr -1 ). We fitted a generalized linear model (GLM), a GLM with eigenvectors spatial filtering (GLM-ESF), and a generalized estimating equations (GEE) approach for each species to examine the potential correlation of nest density with light pollution. Our models are robust and reliable in terms of the ability to deal with data distribution and spatial autocorrelation (SA) issues violating model assumptions. All three models found that nest density is significantly negatively correlated with light pollution for each sea turtle species: the higher light pollution, the lower nest density. The two spatially extended models (GLM-ESF and GEE) show that light pollution influences nest density in a descending order from green turtles, to loggerheads, and then to leatherbacks. The research findings have an implication for sea turtle conservation policy and ordinance making. Near-coastal lights-out ordinances and other approaches to shield lights can protect sea turtles and their nests. The VIIRS DNB light data, having significant improvements over comparable data by its predecessor, the DMSP-OLS, shows promise for continued and improved research about ecological effects of artificial light pollution. Copyright © 2018 Elsevier Ltd. All rights reserved.

Variation in clutch size in relation to nest size in birds

PubMed Central

Møller, Anders P; Adriaensen, Frank; Artemyev, Alexandr; Bańbura, Jerzy; Barba, Emilio; Biard, Clotilde; Blondel, Jacques; Bouslama, Zihad; Bouvier, Jean-Charles; Camprodon, Jordi; Cecere, Francesco; Charmantier, Anne; Charter, Motti; Cichoń, Mariusz; Cusimano, Camillo; Czeszczewik, Dorota; Demeyrier, Virginie; Doligez, Blandine; Doutrelant, Claire; Dubiec, Anna; Eens, Marcel; Eeva, Tapio; Faivre, Bruno; Ferns, Peter N; Forsman, Jukka T; García-Del-Rey, Eduardo; Goldshtein, Aya; Goodenough, Anne E; Gosler, Andrew G; Góźdź, Iga; Grégoire, Arnaud; Gustafsson, Lars; Hartley, Ian R; Heeb, Philipp; Hinsley, Shelley A; Isenmann, Paul; Jacob, Staffan; Järvinen, Antero; Juškaitis, Rimvydas; Korpimäki, Erkki; Krams, Indrikis; Laaksonen, Toni; Leclercq, Bernard; Lehikoinen, Esa; Loukola, Olli; Lundberg, Arne; Mainwaring, Mark C; Mänd, Raivo; Massa, Bruno; Mazgajski, Tomasz D; Merino, Santiago; Mitrus, Cezary; Mönkkönen, Mikko; Morales-Fernaz, Judith; Morin, Xavier; Nager, Ruedi G; Nilsson, Jan-Åke; Nilsson, Sven G; Norte, Ana C; Orell, Markku; Perret, Philippe; Pimentel, Carla S; Pinxten, Rianne; Priedniece, Ilze; Quidoz, Marie-Claude; Remeš, Vladimir; Richner, Heinz; Robles, Hugo; Rytkönen, Seppo; Senar, Juan Carlos; Seppänen, Janne T; da Silva, Luís P; Slagsvold, Tore; Solonen, Tapio; Sorace, Alberto; Stenning, Martyn J; Török, János; Tryjanowski, Piotr; van Noordwijk, Arie J; von Numers, Mikael; Walankiewicz, Wiesław; Lambrechts, Marcel M

2014-01-01

Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nests of 21 species of hole and non-hole-nesting birds. There was a significant, positive relationship between clutch size and the base area of the nest box or the nest, and this relationship did not differ significantly between open nesting and hole-nesting species. The slope of the relationship showed significant intraspecific and interspecific heterogeneity among four species of secondary hole-nesting species, but also among all 116 slope estimates. The estimated relationship between clutch size and nest box base area in study sites with more than a single size of nest box was not significantly different from the relationship using studies with only a single size of nest box. The slope of the relationship between clutch size and nest base area in different species of birds was significantly negatively related to minimum base area, and less so to maximum base area in a given study. These findings are consistent with the hypothesis that bird species have a general reaction norm reflecting the relationship between nest size and clutch size. Further, they suggest that scientists may influence the clutch size decisions of hole-nesting birds through the provisioning of nest boxes of varying sizes. PMID:25478150

Variation in clutch size in relation to nest size in birds.

PubMed

Møller, Anders P; Adriaensen, Frank; Artemyev, Alexandr; Bańbura, Jerzy; Barba, Emilio; Biard, Clotilde; Blondel, Jacques; Bouslama, Zihad; Bouvier, Jean-Charles; Camprodon, Jordi; Cecere, Francesco; Charmantier, Anne; Charter, Motti; Cichoń, Mariusz; Cusimano, Camillo; Czeszczewik, Dorota; Demeyrier, Virginie; Doligez, Blandine; Doutrelant, Claire; Dubiec, Anna; Eens, Marcel; Eeva, Tapio; Faivre, Bruno; Ferns, Peter N; Forsman, Jukka T; García-Del-Rey, Eduardo; Goldshtein, Aya; Goodenough, Anne E; Gosler, Andrew G; Góźdź, Iga; Grégoire, Arnaud; Gustafsson, Lars; Hartley, Ian R; Heeb, Philipp; Hinsley, Shelley A; Isenmann, Paul; Jacob, Staffan; Järvinen, Antero; Juškaitis, Rimvydas; Korpimäki, Erkki; Krams, Indrikis; Laaksonen, Toni; Leclercq, Bernard; Lehikoinen, Esa; Loukola, Olli; Lundberg, Arne; Mainwaring, Mark C; Mänd, Raivo; Massa, Bruno; Mazgajski, Tomasz D; Merino, Santiago; Mitrus, Cezary; Mönkkönen, Mikko; Morales-Fernaz, Judith; Morin, Xavier; Nager, Ruedi G; Nilsson, Jan-Åke; Nilsson, Sven G; Norte, Ana C; Orell, Markku; Perret, Philippe; Pimentel, Carla S; Pinxten, Rianne; Priedniece, Ilze; Quidoz, Marie-Claude; Remeš, Vladimir; Richner, Heinz; Robles, Hugo; Rytkönen, Seppo; Senar, Juan Carlos; Seppänen, Janne T; da Silva, Luís P; Slagsvold, Tore; Solonen, Tapio; Sorace, Alberto; Stenning, Martyn J; Török, János; Tryjanowski, Piotr; van Noordwijk, Arie J; von Numers, Mikael; Walankiewicz, Wiesław; Lambrechts, Marcel M

2014-09-01

Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nests of 21 species of hole and non-hole-nesting birds. There was a significant, positive relationship between clutch size and the base area of the nest box or the nest, and this relationship did not differ significantly between open nesting and hole-nesting species. The slope of the relationship showed significant intraspecific and interspecific heterogeneity among four species of secondary hole-nesting species, but also among all 116 slope estimates. The estimated relationship between clutch size and nest box base area in study sites with more than a single size of nest box was not significantly different from the relationship using studies with only a single size of nest box. The slope of the relationship between clutch size and nest base area in different species of birds was significantly negatively related to minimum base area, and less so to maximum base area in a given study. These findings are consistent with the hypothesis that bird species have a general reaction norm reflecting the relationship between nest size and clutch size. Further, they suggest that scientists may influence the clutch size decisions of hole-nesting birds through the provisioning of nest boxes of varying sizes.

Do common eiders nest in kin groups? Microgeographic genetic structure in a philopatric sea duck

USGS Publications Warehouse

Sonsthagen, S.A.; Talbot, S.L.; Lanctot, Richard B.; McCracken, K.G.

2010-01-01

We investigated local genetic associations among female Pacific common eiders (Somateria mollissima v-nigrum) nesting in a stochastic Arctic environment within two groups of barrier islands (Simpson Lagoon and Mikkelsen Bay) in the Beaufort Sea, Alaska. Nonrandom genetic associations were observed among nesting females using regional spatial autocorrelation analyses for distance classes up to 1000 m in Simpson Lagoon. Nearest-neighbour analyses identified clusters of genetically related females with positive lr values observed for 0-13% and 0-7% of the comparisons in Simpson Lagoon and Mikkelsen Bay, respectively, across years. These results indicate that a proportion of females are nesting in close proximity to more genetically related individuals, albeit at low frequency. Such kin groupings may form through active association between relatives or through natal philopatry and breeding site fidelity. Eiders nest in close association with driftwood, which is redistributed annually by seasonal storms. Yet, genetic associations were still observed. Microgeographic structure may thus be more attributable to kin association than natal philopatry and site fidelity. However, habitat availability may also influence the level of structure observed. Regional structure was present only within Simpson Lagoon and this island group includes at least three islands with sufficient driftwood for colonies, whereas only one island at Mikkelsen Bay has these features. A long-term demographic study is needed to understand more fully the mechanisms that lead to fine-scale genetic structure observed in common eiders breeding in the Beaufort Sea. ?? Published 2010. This article is a US Government work and is in the public domain in the USA.

Common Starlings (Sturnus vulgaris) increasingly select for grazed areas with increasing distance-to-nest.

PubMed

Heldbjerg, Henning; Fox, Anthony D; Thellesen, Peder V; Dalby, Lars; Sunde, Peter

2017-01-01

The abundant and widespread Common Starling (Sturnus vulgaris) is currently declining across much of Europe due to landscape changes caused by agricultural intensification. The proximate mechanisms causing adverse effects to breeding Starlings are unclear, hampering our ability to implement cost-efficient agri-environmental schemes to restore populations to former levels. This study aimed to show how this central foraging farmland bird uses and selects land cover types in general and how use of foraging habitat changes in relation to distance from the nest. We attached GPS-loggers to 17 breeding Starlings at a Danish dairy cattle farm in 2015 and 2016 and analysed their use of different land cover types as a function of distance intervals from the nest and their relative availability. As expected for a central place forager, Starlings increasingly avoided potential foraging areas with greater distance-to-nest: areas ≥ 500 m were selected > 100 times less frequently than areas within 100 m. On average, Starlings selected the land cover category Grazed most frequently, followed by Short Grass, Bare Ground, Meadow and Winter Crops. Starlings compensated for elevated travel costs by showing increasing habitat selection the further they foraged from the nest. Our results highlight the importance of Grazed foraging habitats close to the nest site of breeding Starlings. The ecological capacity of intensively managed farmlands for insectivorous birds like the Starling is decreasing through conversion of the most strongly selected land cover type (Grazed) to the least selected (Winter Crops) which may be further exacerbated through spatial segregation of foraging and breeding habitats.

Common Starlings (Sturnus vulgaris) increasingly select for grazed areas with increasing distance-to-nest

PubMed Central

Fox, Anthony D.; Thellesen, Peder V.; Dalby, Lars; Sunde, Peter

2017-01-01

The abundant and widespread Common Starling (Sturnus vulgaris) is currently declining across much of Europe due to landscape changes caused by agricultural intensification. The proximate mechanisms causing adverse effects to breeding Starlings are unclear, hampering our ability to implement cost-efficient agri-environmental schemes to restore populations to former levels. This study aimed to show how this central foraging farmland bird uses and selects land cover types in general and how use of foraging habitat changes in relation to distance from the nest. We attached GPS-loggers to 17 breeding Starlings at a Danish dairy cattle farm in 2015 and 2016 and analysed their use of different land cover types as a function of distance intervals from the nest and their relative availability. As expected for a central place forager, Starlings increasingly avoided potential foraging areas with greater distance-to-nest: areas ≥ 500 m were selected > 100 times less frequently than areas within 100 m. On average, Starlings selected the land cover category Grazed most frequently, followed by Short Grass, Bare Ground, Meadow and Winter Crops. Starlings compensated for elevated travel costs by showing increasing habitat selection the further they foraged from the nest. Our results highlight the importance of Grazed foraging habitats close to the nest site of breeding Starlings. The ecological capacity of intensively managed farmlands for insectivorous birds like the Starling is decreasing through conversion of the most strongly selected land cover type (Grazed) to the least selected (Winter Crops) which may be further exacerbated through spatial segregation of foraging and breeding habitats. PMID:28771556

The adrenocortical stress-response of Black-legged Kittiwake chicks in relation to dietary restrictions

USGS Publications Warehouse

Kitaysky, A.S.; Piatt, John F.; Wingfield, J.C.; Romano, M.

1999-01-01

In this study we examined hormonal responses of Black-legged Kittiwake (Rissa tridactyla) chicks to experimental variations in energy content and nutritional quality (low or high lipid to protein ratio, LPR) of their food. Starting at the age of 10 days, chicks were fed either high or low LPR fish at 30, 50, 70 and 100% of ad libitum energy intake. After 20 days of treatment, chicks were exposed to a standardized acute handling and restraint stress protocol, where a baseline sample was taken immediately after taking a chick from the nest, and three additional blood samples were taken at intervals up to 50 min. Testosterone and corticosterone titres in plasma were measured via radioimmunoassay. We found that baseline testosterone levels were not significantly affected by the experimental treatments. Food-restricted chicks had elevated baseline and acute stress-induced levels of corticosterone compared to chicks fed ad libitum. An elevation of circulating levels of corticosterone in energetically stressed individuals was further magnified by low nutritional quality of food. Baseline and acute stress-induced corticosterone levels of chicks were negatively correlated with their fat reserves. We conclude that the physiological condition of Black-legged Kittiwake chicks can be assessed reliably by measuring circulating levels of corticosterone. We discuss short-and long-term effects of elevated corticosterone secretion in food-stressed nest-bound chicks.

The adrenocorical stress-response of Black-legged Kittiwake chicks in relation to dietary restrictions

USGS Publications Warehouse

Kitaysky, A.S.; Piatt, John F.; Wingfield, J.C.; Romano, M.

1999-01-01

In this study we examined hormonal responses of Black-legged Kittiwake (Rissa tridactyla) chicks to experimental variations in energy content and nutritional quality (low or high lipid to protein ratio, LPR) of their food. Starting at the age of 10 days, chicks were fed either high or low LPR fish at 30, 50, 70 and 100% of ad libitum energy intake. After 20 days of treatment, chicks were exposed to a standardized acute handling and restraint stress protocol, where a baseline sample was taken immediately after taking a chick from the nest, and three additional blood samples were taken at intervals up to 50 min. Testosterone and corticosterone titres in plasma were measured via radioimmunoassay. We found that baseline testosterone levels were not significantly affected by the experimental treatments. Food-restricted chicks had elevated baseline and acute stress-induced levels of corticosterone compared to chicks fed ad libitum. An elevation of circulating levels of corticosterone in energetically stressed individuals was further magnified by low nutritional quality of food. Baseline and acute stress-induced corticosterone levels of chicks were negatively correlated with their fat reserves. We conclude that the physiological condition of Black-legged Kittiwake chicks can be assessed reliably by measuring circulating levels of corticosterone. We discuss short- and long-term effects of elevated corticosterone secretion in food-stressed nest-bound chicks.

Environmental change mediates mate choice for an extended phenotype, but not for mate quality.

PubMed

Head, Megan L; Fox, Rebecca J; Barber, Iain

2017-01-01

Sexual cues, including extended phenotypes, are expected to be reliable indicators of male genetic quality and/or provide information on parental quality. However, the reliability of these cues may be dependent on stability of the environment, with heterogeneity affecting how selection acts on such traits. Here, we test how environmental change mediates mate choice for multiple sexual traits, including an extended phenotype--the structure of male-built nests - in stickleback fish. First, we manipulated the dissolved oxygen (DO) content of water to create high or low DO environments in which male fish built nests. Then we recorded the mate choice of females encountering these males (and their nests), under either the same or reversed DO conditions. Males in high DO environments built more compact nests than those in low DO conditions and males adjusted their nest structure in response to changing conditions. Female mate choice for extended phenotype (male nests) was environmentally dependent (females chose more compact nests in high DO conditions), while female choice for male phenotype was not (females chose large, vigorous males regardless of DO level). Examining mate choice in this dynamic context suggests that females evaluate the reliability of multiple sexual cues, taking into account environmental heterogeneity. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Are there optimal densities for prairie birds?

USGS Publications Warehouse

Skagen, S.K.; Adams, A.A.Y.

2010-01-01

The major forces of food and predation shape fitness-enhancing decisions of birds at all stages of their life cycles. During the breeding season, birds can minimize nest loss due to predation by selecting sites with a lower probability of predation. To understand the environmental and social aspects and consequences of breedingsite selection in prairie birds, we explored variation in nest-survival patterns of the Lark Bunting (Calamospiza melanocorys) in the shortgrass prairie region of North America. Over four breeding seasons, we documented the survival of 405 nests, conducted 60 surveys to estimate bird densities, and measured several vegetative features to describe habitat structure in 24 randomly selected study plots. Nest survival varied with the buntings' density as described by a quadratic polynomial, increasing with density below 1.5 birds ha-1 and decreasing with density between 1.5 and 3 birds ha-1, suggesting that an optimal range of densities favors reproductive success of the Lark Bunting, which nests semi-colonially. Nest survival also increased with increasing vegetation structure of study plots and varied with age of the nest, increasing during early incubation and late in the nestling stage and declining slightly from mid-incubation to the middle of the nestling period. The existence of an optimal range of densities in this semi-colonial species can be elucidated by the "commodity-selection hypothesis" at low densities and density dependence at high densities. ?? The Cooper Ornithological Society 2010.

Hierarchically nested river landform sequences

NASA Astrophysics Data System (ADS)

Pasternack, G. B.; Weber, M. D.; Brown, R. A.; Baig, D.

2017-12-01

River corridors exhibit landforms nested within landforms repeatedly down spatial scales. In this study we developed, tested, and implemented a new way to create river classifications by mapping domains of fluvial processes with respect to the hierarchical organization of topographic complexity that drives fluvial dynamism. We tested this approach on flow convergence routing, a morphodynamic mechanism with different states depending on the structure of nondimensional topographic variability. Five nondimensional landform types with unique functionality (nozzle, wide bar, normal channel, constricted pool, and oversized) represent this process at any flow. When this typology is nested at base flow, bankfull, and floodprone scales it creates a system with up to 125 functional types. This shows how a single mechanism produces complex dynamism via nesting. Given the classification, we answered nine specific scientific questions to investigate the abundance, sequencing, and hierarchical nesting of these new landform types using a 35-km gravel/cobble river segment of the Yuba River in California. The nested structure of flow convergence routing landforms found in this study revealed that bankfull landforms are nested within specific floodprone valley landform types, and these types control bankfull morphodynamics during moderate to large floods. As a result, this study calls into question the prevailing theory that the bankfull channel of a gravel/cobble river is controlled by in-channel, bankfull, and/or small flood flows. Such flows are too small to initiate widespread sediment transport in a gravel/cobble river with topographic complexity.

Percolation in insect nest networks: Evidence for optimal wiring

NASA Astrophysics Data System (ADS)

Valverde, Sergi; Corominas-Murtra, Bernat; Perna, Andrea; Kuntz, Pascale; Theraulaz, Guy; Solé, Ricard V.

2009-06-01

Optimization has been shown to be a driving force for the evolution of some biological structures, such as neural maps in the brain or transport networks. Here we show that insect networks also display characteristic traits of optimality. By using a graph representation of the chamber organization of termite nests and a disordered lattice model, it is found that these spatial nests are close to a percolation threshold. This suggests that termites build efficient systems of galleries spanning most of the nest volume at low cost. The evolutionary consequences are outlined.

Optimal Design in Three-Level Block Randomized Designs with Two Levels of Nesting: An ANOVA Framework with Random Effects

ERIC Educational Resources Information Center

Konstantopoulos, Spyros

2013-01-01

Large-scale experiments that involve nested structures may assign treatment conditions either to subgroups such as classrooms or to individuals such as students within subgroups. Key aspects of the design of such experiments include knowledge of the variance structure in higher levels and the sample sizes necessary to reach sufficient power to…

The effect of predation on begging-call evolution in nestling wood warblers.

PubMed

Haskell

1999-04-01

I combined a comparative study of begging in ground- and tree-nesting wood warblers (Parulidae) with experimental measures of the predation costs of warbler begging calls. Throughout their development, ground-nesting warbler nestlings had significantly higher-frequency begging calls than did tree-nesting warblers. There was also a trend for ground-nesting birds to have less rapidly modulated calls. There were no consistent associations between nesting site and the amplitude of the calls. Using miniature walkie-talkies hidden inside artificial nests, I reciprocally transplanted the begging calls of 5- and 8-day-old black-throated blue warblers, Dendroica caerulescens (tree-nesting) and ovenbirds, Seiurus aurocapillus (ground-nesting) and measured the corresponding changes in rates of nest predation. For the begging calls of 8-day-old nestlings, but not those of 5-day-olds, the calls of the tree-nesting species coming from ground nests incurred greater costs than did the calls of ground nesters. The reciprocal transplant had little effect on the rate of predation. Tooth imprints on clay eggs placed in artificial nests indicated that eastern chipmunks, Tamias striatus, were responsible for the increased cost of begging for black-throated blue calls coming from the ground. These data suggest that nest predation may be responsible for maintaining some of the interspecific differences in the acoustic structure of begging calls. Copyright 1999 The Association for the Study of Animal Behaviour.

The nest growth of the neotropical mound-building termite, Cornitermes cumulans: a micromorphological analysis.

PubMed

Cosarinsky, Marcela I

2011-01-01

The nests of Cornitermes cumulans K. (Isoptera: Termitidae), a very common termite in South American grasslands, display notable morphological transformations during the development of the colony. Young colonies inhabit small subterranean nests that develop into large, conspicuous, epigean mounds, inhabited by very populous colonies. Those macromorphological transformations are accompanied by micromorphological changes occurring gradually in the nest walls. The micromorphological changes during nest development described in the present study expand on previous macromorphological descriptions by explaining the re-organization of the soil components during nest growth. In subterranean nests, walls are composed of piles of lensshaped aggregates of soil material, each one surrounded by a thin organic coating. As the nest grows, mound walls are constructed by disassembling this first lenticular structure and rearranging the materials in a new fabric, where sand grains are loosely distributed among soil microaggregates of organic matter and clay. This is also a temporary construction, because the walls of large nests are composed of a porous mass of sands densely cemented with organic matter and clay in the mound, and a compact mass of the same components in the floor.

Predictive habitat models derived from nest-box occupancy for the endangered Carolina northern flying squirrel in the southern Appalachians

USGS Publications Warehouse

Ford, W. Mark; Evans, A.M.; Odom, Richard H.; Rodrigue, Jane L.; Kelly, C.A.; Abaid, Nicole; Diggins, Corinne A.; Newcomb, Doug

2016-01-01

In the southern Appalachians, artificial nest-boxes are used to survey for the endangered Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus), a disjunct subspecies associated with high elevation (>1385 m) forests. Using environmental parameters diagnostic of squirrel habitat, we created 35 a priori occupancy models in the program PRESENCE for boxes surveyed in western North Carolina, 1996-2011. Our best approximating model showed CNFS denning associated with sheltered landforms and montane conifers, primarily red spruce Picea rubens. As sheltering decreased, decreasing distance to conifers was important. Area with a high probability (>0.5) of occupancy was distributed over 18662 ha of habitat, mostly across 10 mountain ranges. Because nest-box surveys underrepresented areas >1750 m and CNFS forage in conifers, we combined areas of high occupancy with conifer GIS coverages to create an additional distribution model of likely habitat. Regionally, above 1385 m, we determined that 31795 ha could be occupied by CNFS. Known occupied patches ranged from

Nest design in a changing world: great tit Parus major nests from a Mediterranean city environment as a case study.

PubMed

Lambrechts, Marcel M; Charmantier, Anne; Demeyrier, Virginie; Lucas, Annick; Perret, Samuel; Abouladzé, Matthieu; Bonnet, Michel; Canonne, Coline; Faucon, Virginie; Grosset, Stéphanie; le Prado, Gaëlle; Lidon, Frédéric; Noell, Thierry; Pagano, Pascal; Perret, Vincent; Pouplard, Stéphane; Spitaliéry, Rémy; Bernard, Cyril; Perret, Philippe; Blondel, Jacques; Grégoire, Arnaud

2017-12-01

Investigations of urbanization effects on birds have focused mainly on breeding traits expressed after the nest-building stage (e.g. first-egg date, clutch size, breeding success, and offspring characteristics). Urban studies largely ignored how and why the aspects of nest building might be associated with the degree of urbanization. As urban environments are expected to present novel environmental changes relative to rural environments, it is important to evaluate how nest-building behavior is impacted by vegetation modifications associated with urbanization. To examine nest design in a Mediterranean city environment, we allowed urban great tits ( Parus major ) to breed in nest boxes in areas that differed in local vegetation cover. We found that different measures of nest size or mass were not associated with vegetation cover. In particular, nests located adjacent to streets with lower vegetation cover were not smaller or lighter than nests in parks with higher vegetation cover. Nests adjacent to streets contained more pine needles than nests in parks. In addition, in nests adjacent to streets, nests from boxes attached to pine trees contained more pine needles than nests from boxes attached to other trees. We suggest that urban-related alterations in vegetation cover do not directly impose physical limits on nest size in species that are opportunistic in the selection of nesting material. However, nest composition as reflected in the use of pine needles was clearly affected by habitat type and the planted tree species present, which implies that rapid habitat change impacts nest composition. We do not exclude that urbanization might impact other aspects of nest building behaviour not covered in our study (e.g. costs of searching for nest material), and that the strengths of the associations between urbanization and nest structures might differ among study populations or species.

Is the nestedness of metazoan parasite assemblages of marine fishes from the southeastern Pacific coast a pattern associated with the geographical distributional range of the host?

PubMed

González, M T; Oliva, M E

2009-04-01

Nested structure is a pattern originally described in island biogeography to characterize how a set of species is distributed among a set of islands. In parasite communities, nestedness has been intensively studied among individual fish from a locality. However, nested patterns among parasite assemblages from different host populations (localities) have scarcely been investigated. We recorded the occurrence of parasites in 9 fish species widely distributed along the southeastern Pacific coast to determine whether the ecto- and endoparasite assemblages of marine fishes show a nested structure associated with host distributional range. Nestedness was tested using Brualdi-Sanderson index of discrepancy (BR); and 5 null models incorporated in a 'Nestedness' programme (Ulrich, 2006). The ecto- and endoparasite richness do not show similar patterns of latitudinal gradients among fish hosts, with 33-66% of analysed ectoparasite assemblages, and 25-75% of endoparasite assemblages showing nested structures through the host distributional range. For ectoparasites, species richness gradients and nested structure (when present) might be associated with decreased host densities or could reflect negative environmental conditions in the distributional border of the host species, whereas for endoparasites might be caused by geographical breaks of prey or changes in prey availability (intermediate hosts). The sampled extension of the distributional range of the host species, as well as the lack of specificity of some parasites, could influence the detection of nestedness.

Reproductive Performance of a Declining Forest Passerine in Relation to Environmental and Social Factors: Implications for Species Conservation

PubMed Central

Grendelmeier, Alex; Arlettaz, Raphaël; Gerber, Michael; Pasinelli, Gilberto

2015-01-01

Identifying factors influencing a species' ecological niche and demography is a prerequisite for species conservation. However, our understanding of the interplay between demographic rates and biotic/abiotic factors is still poor for most species of conservation concern. We evaluated relevance of eight hypotheses relating to timing of breeding, temporal nest exposure, nest concealment, topography, tree structure, predation risk and disturbance, density dependence and weather for explaining variation in reproductive performance of the declining wood warbler Phylloscopus sibilatrix in northern Switzerland. Reproductive performance was monitored with cameras at 136 nests from 2010 to 2012 and was associated to temporal exposure, timing of breeding and concealment of nests. Daily nest survival was positively related to the number of grass and sedge tussocks, nest concealment and nest age. Clutch size and number of fledglings decreased, the later in the season a nest was initiated. Nest survival over an average nesting period of 31 days was 46.9 ± 0.07% (mean ± SE), daily nest survival rate was 0.976 ± 0.002. As for many ground-breeding birds, nest predation was the principal cause of nest failure, accounting for 79% of all nest losses. Conservation measures should aim at increasing the area of relatively homogenous forest stands featuring suitable habitats characterized by abundant and accessible grass and sedge tussocks. In managed forests, such conditions can be found in stands of middle age (i.e. pole wood) with little to no shrub layer. PMID:26172954

Reproductive Performance of a Declining Forest Passerine in Relation to Environmental and Social Factors: Implications for Species Conservation.

PubMed

Grendelmeier, Alex; Arlettaz, Raphaël; Gerber, Michael; Pasinelli, Gilberto

2015-01-01

Identifying factors influencing a species' ecological niche and demography is a prerequisite for species conservation. However, our understanding of the interplay between demographic rates and biotic/abiotic factors is still poor for most species of conservation concern. We evaluated relevance of eight hypotheses relating to timing of breeding, temporal nest exposure, nest concealment, topography, tree structure, predation risk and disturbance, density dependence and weather for explaining variation in reproductive performance of the declining wood warbler Phylloscopus sibilatrix in northern Switzerland. Reproductive performance was monitored with cameras at 136 nests from 2010 to 2012 and was associated to temporal exposure, timing of breeding and concealment of nests. Daily nest survival was positively related to the number of grass and sedge tussocks, nest concealment and nest age. Clutch size and number of fledglings decreased, the later in the season a nest was initiated. Nest survival over an average nesting period of 31 days was 46.9 ± 0.07% (mean ± SE), daily nest survival rate was 0.976 ± 0.002. As for many ground-breeding birds, nest predation was the principal cause of nest failure, accounting for 79% of all nest losses. Conservation measures should aim at increasing the area of relatively homogenous forest stands featuring suitable habitats characterized by abundant and accessible grass and sedge tussocks. In managed forests, such conditions can be found in stands of middle age (i.e. pole wood) with little to no shrub layer.

Contrasting species and functional beta diversity in montane ant assemblages.

PubMed

Bishop, Tom R; Robertson, Mark P; van Rensburg, Berndt J; Parr, Catherine L

2015-09-01

Beta diversity describes the variation in species composition between sites and can be used to infer why different species occupy different parts of the globe. It can be viewed in a number of ways. First, it can be partitioned into two distinct patterns: turnover and nestedness. Second, it can be investigated from either a species identity or a functional-trait point of view. We aim to document for the first time how these two aspects of beta diversity vary in response to a large environmental gradient. Maloti-Drakensberg Mountains, southern Africa. We sampled ant assemblages along an extensive elevational gradient (900-3000 m a.s.l.) twice yearly for 7 years, and collected functional-trait information related to the species' dietary and habitat-structure preferences. We used recently developed methods to partition species and functional beta diversity into their turnover and nestedness components. A series of null models were used to test whether the observed beta diversity patterns differed from random expectations. Species beta diversity was driven by turnover, but functional beta diversity was composed of both turnover and nestedness patterns at different parts of the gradient. Null models revealed that deterministic processes were likely to be responsible for the species patterns but that the functional changes were indistinguishable from stochasticity. Different ant species are found with increasing elevation, but they tend to represent an increasingly nested subset of the available functional strategies. This finding is unique and narrows down the list of possible factors that control ant existence across elevation. We conclude that diet and habitat preferences have little role in structuring ant assemblages in montane environments and that some other factor must be driving the non-random patterns of species turnover. This finding also highlights the importance of distinguishing between different kinds of beta diversity.

Diets of California spotted owls in the Sierra National Forest

Treesearch

Thomas E. Munton; Kenneth D. Johnson; George N. Steger; Gary P. Eberlein

2002-01-01

From May 1987 through October 1992 and from July through August 1998, we studied diets of California spotted owls (Strix occidentalis occidentalis). Regurgitated pellets were collected at roost and nest sites between 1,000 and 7,600 ft elevation in the Sierra National Forest and were examined for remnant bones, feathers, and insect exoskeletons....

Nesting biology of Black-shouldered Kite (Elanus caeruleus) in oil palm landscape in Carey Island, Peninsular Malaysia.

PubMed

Ramli, Rosli; Fauzi, Aimi

2018-03-01

Black-shouldered Kite ( Elanus caeruleus ) is a well-known raptor that inhabits open areas such as oil palm plantation or paddy field. To determine preferable habitat and nesting site of Black-shouldered Kite in oil palm landscape, we conducted a study on Black-shouldered Kite's nesting biology in Carey Island, Selangor, Malaysia. We divided the island into six types of habitat and conducted road-side count of Black-shouldered Kite from April 2009 to February 2011. Whenever the Black-shouldered Kite was detected, we thoroughly searched the surrounding area for their nest. In total, we have recorded forty nests. The nests were built on 15 species of trees but most of the trees shared common physical characteristics. Some novice breeders also used oil palm tree as their nesting site. Structure and building materials of nests constructed on oil palm trees were different from nests built on other trees. Of all breeding attempts, only four nests which were located in residential area adjacent to young oil palm habitat were successful. Among important characteristics of successful nesting site include taller trees with strong branches and good leaf coverage. These trees not only protect nests from predator detection (except from other predatory birds) and physical environment but also facilitate Black-shouldered Kite's foraging activities by providing good vantage point.

Variation in the Structure of Bird Nests between Northern Manitoba and Southeastern Ontario

PubMed Central

Crossman, Carla A.; Rohwer, Vanya G.; Martin, Paul R.

2011-01-01

Traits that converge in appearance under similar environmental conditions among phylogenetically independent lineages are thought to represent adaptations to local environments. We tested for convergence in nest morphology and composition of birds breeding in two ecologically different locations in Canada: Churchill in northern Manitoba and Elgin in southeastern Ontario. We examined nests from four families of passerine birds (Turdidae: Turdus, Parulidae: Dendroica, Emberizidae: Passerculus and Fringillidae: Carduelis) where closely related populations or species breed in both locations. Nests of American Robins, Yellow Warblers, and Carduelis finches had heavier nest masses, and tended to have thicker nest-walls, in northern Manitoba compared with conspecifics or congenerics breeding in southeastern Ontario. Together, all species showed evidence for wider internal and external nest-cup diameters in northern Manitoba, while individual species showed varying patterns for internal nest-cup and external nest depths. American Robins, Yellow Warblers, and Carduelis finches in northern Manitoba achieved heavier nest masses in different ways. American Robins increased all materials in similar proportions, and Yellow Warblers and Common Redpolls used greater amounts of select materials. While changes in nest composition vary uniquely for each species, the pattern of larger nests in northern Manitoba compared to southeastern Ontario in three of our four phylogenetically-independent comparisons suggests that birds are adapting to similar selective pressures between locations. PMID:21552515

Timing of nest vegetation measurement may obscure adaptive significance of nest-site characteristics: A simulation study.

PubMed

McConnell, Mark D; Monroe, Adrian P; Burger, Loren Wes; Martin, James A

2017-02-01

Advances in understanding avian nesting ecology are hindered by a prevalent lack of agreement between nest-site characteristics and fitness metrics such as nest success. We posit this is a result of inconsistent and improper timing of nest-site vegetation measurements. Therefore, we evaluated how the timing of nest vegetation measurement influences the estimated effects of vegetation structure on nest survival. We simulated phenological changes in nest-site vegetation growth over a typical nesting season and modeled how the timing of measuring that vegetation, relative to nest fate, creates bias in conclusions regarding its influence on nest survival. We modeled the bias associated with four methods of measuring nest-site vegetation: Method 1-measuring at nest initiation, Method 2-measuring at nest termination regardless of fate, Method 3-measuring at nest termination for successful nests and at estimated completion for unsuccessful nests, and Method 4-measuring at nest termination regardless of fate while also accounting for initiation date. We quantified and compared bias for each method for varying simulated effects, ranked models for each method using AIC, and calculated the proportion of simulations in which each model (measurement method) was selected as the best model. Our results indicate that the risk of drawing an erroneous or spurious conclusion was present in all methods but greater with Method 2 which is the most common method reported in the literature. Methods 1 and 3 were similarly less biased. Method 4 provided no additional value as bias was similar to Method 2 for all scenarios. While Method 1 is seldom practical to collect in the field, Method 3 is logistically practical and minimizes inherent bias. Implementation of Method 3 will facilitate estimating the effect of nest-site vegetation on survival, in the least biased way, and allow reliable conclusions to be drawn.

Patch size and landscape effects on density and nesting success of grassland birds

USGS Publications Warehouse

Winter, Maiken; Johnson, Douglas H.; Shaffer, Jill A.; Donovan, Therese M.; Svedarsky, W. Daniel

2006-01-01

Current management recommendations for grassland birds in North America emphasize providing large patches of grassland habitat within landscapes that have few forest or shrubland areas. These Bird Conservation Areas are being proposed under the assumption that large patches of habitat in treeless landscapes will maintain viable populations of grassland birds. This assumption requires that patch size and landscape features affect density and nesting success of grassland birds, and that these effects are consistent among years and regions and across focal species. However, these assumptions have not yet been validated for grassland birds, and the relative importance of local vegetation structure, patch size, and landscape composition on grassland bird populations is not well known. In addition, factors influencing grassland bird nesting success have been investigated mostly in small-scale and short-duration studies. To develop management guidelines for grassland birds, we tested the spatial and temporal repeatability of the influence of patch size and landscape composition on density and nesting success of 3 grassland passerines, after controlling for local-scale vegetation structure, climate, and—when analyzing nest success—bird density. We conducted our study during 4 years (1998–2001) in 44 study plots that were set up in 3 regions of the northern tallgrass prairie in Minnesota and North Dakota, USA. In these study plots we measured density and nesting success of clay-colored sparrows (Spizella pallida), Savannah sparrows (Passerculus sandwichensis), and bobolinks (Dolichonyx oryzivorus). Statistical models indicated that density was influenced by patch size, landscape, region, and local vegetation structure more so than by local vegetation structure alone. Both magnitude and direction of the response of density to patch size varied among regions, years, and species. In contrast, the direction of landscape effects was consistent among regions, years, and between Savannah sparrows and bobolinks. In each species, this landscape effect was independent of patch size. Nesting success was not clearly influenced by patch size or landscape composition, and none of the factors that influenced avian density also influenced nesting success in any of the 3 species. General statements on “optimal habitat” for grassland birds should therefore be viewed cautiously. Instead, long-term studies in different regions as well as a deeper understanding of the local system are needed to determine which factors are most important for grassland birds in a particular area.

Methods for Casting Subterranean Ant Nests

PubMed Central

Tschinkel, Walter R.

2010-01-01

The study of subterranean ant nests has been impeded by the difficulty of rendering their structures in visible form. Here, several different casting materials are shown to make perfect casts of the underground nests of ants. Each material (dental plaster, paraffin wax, aluminum, zinc) has advantages and limitations, which are discussed. Some of the materials allow the recovery of the ants entombed in the casts, allowing a census of the ants to be connected with features of their nest architecture. The necessary equipment and procedures are described in the hope that more researchers will study this very important aspect of ant natural history. PMID:20673073

Beach erosion and nest site selection by the leatherback sea turtle Dermochelys coriacea (Testudines: Dermochelyidae) and implications for management practices at Playa Gandoca, Costa Rica.

PubMed

Spanier, Matthew J

2010-12-01

Leatherback sea turtles (Dermochelys coriacea) nest on dynamic, erosion-prone beaches. Erosive processes and resulting nest loss have long been presumed to be a hindrance to clutch survival. In order to better understand how leatherbacks cope with unstable nesting beaches, I investigated the role of beach erosion in leatherback nest site selection at Playa Gandoca, Costa Rica. I also examined the potential effect of nest relocation, a conservation strategy in place at Playa Gandoca to prevent nest loss to erosion, on the temperature of incubating clutches. I monitored changes in beach structure as a result of erosion at natural nest sites during the time the nest was laid, as well as in subsequent weeks. To investigate slope as a cue for nest site selection, I measured the slope of the beach where turtles ascended from the sea to nest, as well as the slopes at other random locations on the beach for comparison. I examined temperature differences between natural and relocated nest sites with thermocouples placed in the sand at depths typical of leatherback nests. Nests were distributed non-randomly in a clumped distribution along the length of the beach and laid at locations that were not undergoing erosion. The slope at nest sites was significantly different than at randomly chosen locations on the beach. The sand temperature at nest depths was significantly warmer at natural nest sites than at locations of relocated nests. The findings of this study suggest leatherbacks actively select nest sites that are not undergoing erosive processes, with slope potentially being used as a cue for site selection. The relocation of nests appears to be inadvertently cooling the nest environment. Due to the fact that leatherback clutches undergo temperature-dependent sex determination, the relocation of nests may be producing an unnatural male biasing of hatchlings. The results of this study suggest that the necessity of relocation practices, largely in place to protect nests from erosion, should be reevaluated to ensure the proper conservation of this critically endangered species.

MAGNETIC FIELD OF THE VELA C MOLECULAR CLOUD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusune, Takayoshi; Sugitani, Koji; Nakamura, Fumitaka

We have performed extensive near-infrared ( JHK {sub s}) imaging polarimetry toward the Vela C molecular cloud, which covers the five high-density sub-regions (North, Centre-Ridge, Centre-Nest, South-Ridge, and South-Nest) with distinct morphological characteristics. The obtained polarization vector map shows that three of these sub-regions have distinct plane-of-the-sky (POS) magnetic-field characteristics according to the morphological characteristics. (1) In the Centre-Ridge sub-region, a dominating ridge, the POS magnetic field is mostly perpendicular to the ridge. (2) In the Centre-Nest sub-region, a structure having a slightly extended nest of filaments, the POS magnetic field is nearly parallel to its global elongation. (3) Inmore » the South-Nest sub-region, which has a network of small filaments, the POS magnetic field appears to be chaotic. By applying the Chandrasekhar–Fermi method, we derived the POS magnetic field strength as ∼70–310 μ G in the Centre-Ridge, Centre-Nest, and South-Ridge sub-regions. In the South-Nest sub-region, the dispersion of polarization angles is too large to apply the C-F method. Because the velocity dispersion in this sub-region is not greater than those in the other sub-regions, we suggest that the magnetic field in this sub-region is weaker than those in other sub-regions. We also discuss the relationship between the POS magnetic field (configuration and strength) and the cloud structure of each sub-region.« less

Phenological shifts conserve thermal niches in North American birds and reshape expectations for climate-driven range shifts.

PubMed

Socolar, Jacob B; Epanchin, Peter N; Beissinger, Steven R; Tingley, Morgan W

2017-12-05

Species respond to climate change in two dominant ways: range shifts in latitude or elevation and phenological shifts of life-history events. Range shifts are widely viewed as the principal mechanism for thermal niche tracking, and phenological shifts in birds and other consumers are widely understood as the principal mechanism for tracking temporal peaks in biotic resources. However, phenological and range shifts each present simultaneous opportunities for temperature and resource tracking, although the possible role for phenological shifts in thermal niche tracking has been widely overlooked. Using a canonical dataset of Californian bird surveys and a detectability-based approach for quantifying phenological signal, we show that Californian bird communities advanced their breeding phenology by 5-12 d over the last century. This phenological shift might track shifting resource peaks, but it also reduces average temperatures during nesting by over 1 °C, approximately the same magnitude that average temperatures have warmed over the same period. We further show that early-summer temperature anomalies are correlated with nest success in a continental-scale database of bird nests, suggesting avian thermal niches might be broadly limited by temperatures during nesting. These findings outline an adaptation surface where geographic range and breeding phenology respond jointly to constraints imposed by temperature and resource phenology. By stabilizing temperatures during nesting, phenological shifts might mitigate the need for range shifts. Global change ecology will benefit from further exploring phenological adjustment as a potential mechanism for thermal niche tracking and vice versa.

Nest survival relative to patch size in a highly fragmented shortgrass prairie landscape

USGS Publications Warehouse

Skagen, S.K.; Yackel Adams, A.A.; Adams, R.D.

2005-01-01

Understanding the influences of habitat fragmentation on vertebrate populations is essential for the protection and ecological restoration of strategic sites for native species. We examined the effects of prairie fragmentation on avian reproductive success using artificial and natural nests on 26 randomly selected, privately owned patches of shortgrass prairie ranging in size from 7 to 454 ha within a cropland matrix in Washington County, Colorado, summer 2000. Survival trends of artificial and natural nests differed. Daily survival of artificial nests increased with patch size up to about 65 ha and differed little at larger patch sizes, whereas daily survival of Lark Bunting (Calamospiza melanocorys) and Horned Lark (Eremophila alpestris) nests decreased with increasing size of the grassland patch. We hypothesize that our unexpected findings of lower survival of natural nests with increasing patch sizes and different trends between artificial and natural nests are due to the particular structure of predator communities in our study area and the ways in which individual predators respond to artificial and natural nests. We recommend that the value of small habitat patches in highly fragmented landscapes not be overlooked.

The Nest Growth of the Neotropical Mound-Building Termite, Cornitermes cumulans: A Micromorphological Analysis

PubMed Central

Cosarinsky, Marcela I.

2011-01-01

The nests of Cornitermes cumulans K. (Isoptera: Termitidae), a very common termite in South American grasslands, display notable morphological transformations during the development of the colony. Young colonies inhabit small subterranean nests that develop into large, conspicuous, epigean mounds, inhabited by very populous colonies. Those macromorphological transformations are accompanied by micromorphological changes occurring gradually in the nest walls. The micromorphological changes during nest development described in the present study expand on previous macromorphological descriptions by explaining the re-organization of the soil components during nest growth. In subterranean nests, walls are composed of piles of lensshaped aggregates of soil material, each one surrounded by a thin organic coating. As the nest grows, mound walls are constructed by disassembling this first lenticular structure and rearranging the materials in a new fabric, where sand grains are loosely distributed among soil microaggregates of organic matter and clay. This is also a temporary construction, because the walls of large nests are composed of a porous mass of sands densely cemented with organic matter and clay in the mound, and a compact mass of the same components in the floor. PMID:22224433

Effects of experimentally sustained elevated testosterone on incubation behaviour and reproductive success in female great tits (Parus major).

PubMed

de Jong, Berber; Lens, Luc; Amininasab, Seyed Mehdi; van Oers, Kees; Darras, Veerle M; Eens, Marcel; Pinxten, Rianne; Komdeur, Jan; Groothuis, Ton G G

2016-05-01

In many seasonally breeding birds, female and male testosterone (T) levels peak at the start of the breeding season, coinciding with pair bonding and nesting activities. Shortly after the onset of egg laying, T levels slowly decline to baseline levels in both sexes, but more rapidly so in females. During this period, T in males may still function to facilitate territorial behaviour, mate guarding and extra pair copulations, either via short lasting peaks or elevated basal levels of the hormone. In some species, however, males become insensitive to increased T after the onset of egg laying. It has been postulated that in these species bi-parental care is essential for offspring survival, as T is known to inhibit paternal care. However, only very few studies have analysed this for females. As females are heavily involved in parental care, they too might become insensitive to T after egg laying. Alternatively, because territorial defence, mate guarding and extra pair copulations are expected to be less important for females than for males, they may not have had the need to evolve a mechanism to become insensitive to T during the period of maternal care, because their natural T levels are never elevated during this part of the breeding season anyway. We tested these alternative hypotheses in female great tits (Parus major). Male great tits have previously been shown to be insensitive to T after egg laying with regard to nestling feeding behaviour (but not song rate). When females had started nest building, we experimentally elevated their T levels up to the nestling feeding phase, and measured incubation behaviour (only females incubate) and reproductive success. T did not significantly affect nest building or egg laying behaviour, although egg laying tended to be delayed in T females. Females with experimentally enhanced T maintained lower temperature during incubation but did not spend less time incubating. This might explain the reduced hatching success of their eggs, smaller brood size and lower number of fledglings we found in this study. As in this species T-dependent behaviour by females during the phase of parental care is not needed, the results support the hypothesis that in this species the need for selection in favour of T-insensitivity did not occur. Copyright © 2016 Elsevier Inc. All rights reserved.

Brain and gonadal aromatase activity and steroid hormone levels in female and polymorphic males of the peacock blenny Salaria pavo.

PubMed

Gonçalves, David; Teles, Magda; Alpedrinha, João; Oliveira, Rui F

2008-11-01

In the peacock blenny Salaria pavo large males with well-developed secondary sexual characters establish nests and attract females while small "sneaker" males mimic female sexual displays in order to approach the nests of larger males and parasitically fertilize eggs. These alternative reproductive tactics are sequential, as sneakers irreversibly switch into nesting males. This transition involves major morphologic and behavioral changes and is likely to be mediated by hormones. This study focuses on the role of aromatase, an enzyme that catalyses the conversion of androgens into estrogens, in the regulation of male sexual polymorphism in S. pavo. For this, sex steroid plasma levels and aromatase activity (AA) in gonads, whole brain and brain macroareas were determined in sneakers, transitional males (i.e. sneakers undergoing the transition into nesting males), nesting males and females collected in the field. AA was much higher in ovarian tissue than in testicular tissue and accordingly circulating estradiol levels were highest in females. This supports the view that elevated AA and estradiol levels are associated with the development of a functional ovary. Transitional males are in a non-reproductive phase and had underdeveloped testes when compared with sneakers and nesting males. Testicular AA was approximately 10 times higher in transitional males when compared with sneakers and nesting males, suggesting high AA has a suppressive effect on testicular development. Nesting males had significantly higher plasma levels of both testosterone (T) and 11-ketotestosterone when compared with the other male morphs and previous studies demonstrated that these androgens suppress female-like displays in sneakers. In the brain, AA was highest in macroareas presumably containing hypothalamic nuclei traditionally associated with the regulation of reproductive behaviors. Overall, females presented the highest levels of brain AA. In male morphs AA increased from sneakers, to transitional males, to nesting males in all brain macroareas. These results suggest that the transition into the nesting male tactic is accompanied both by an increase in testicular androgen production and by a higher conversion of androgens into estrogens in the brain. The increase in androgen production is likely to mediate the development of male secondary sexual characters while the increase in brain AA may be related to the behavioral changes associated with tactic transition.

Osprey distribution, abundance, and status in western North America: III. The Baja California and Gulf of California population

USGS Publications Warehouse

Henny, C.J.; Anderson, D.W.

1979-01-01

-An estimated 810 ? 55 pairs (minimum estimate) of ospreys (Pandion haliaetus) were nesting in the study area during our survey (24 March-l April 1977). Approximately 174 pairs nested along the Pacific side of Baja California, 255 pairs along the gulf side, 187 pairs on the Midriff Islands, and 194 pairs in coastal Sonora and Sinaloa. Most nested on cliffs adjacent to the sea (59%); some nested on cactus in flat terrain (26%). Seven per cent nested on the ground, three percent nested in mangroves and other trees in the southern portion of the study area,.and four percent nested on man-made structures. The extreme northwestern Baja California population that was extirpated early in this century has not recovered. However, several populations immediately to the south along the Pacific Coast now appear stationary. Pesticide residues in osprey eggs from Mexico were among the lowest reported for the species in North America.

Superpredator proximity and landscape characteristics alters nest site selection and breeding success of a subordinate predator.

PubMed

Atuo, Fidelis Akunke; O'Connell, Timothy John

2018-03-01

Selecting nesting habitat that minimizes predation risk but maximizes foraging success is one of the most important decisions in avian life history. This takes on added complexity when a predator is faced with the challenge of avoiding fellow predators. We assessed the importance of local and landscape vegetation, food abundance, and predation risk on nest site selection and nest survival in a subordinate raptor (Mississippi Kite; Ictinia mississippiensis) nesting in proximity to two superpredators, Red-tailed hawk (Buteo jamaicensis) and Great horned owl (Bubo virginianus). All three species nested in trees in a grassland landscape. In this landscape, kites favored upland trees and shrubs, avoiding their more typical riparian forest association elsewhere in the species' range. Compared to random conditions, kites selected nest sites with high tree density and more closed canopy in the surrounding area. Mississippi Kite selection was not related to food abundance but could be explained by the presence of superpredators (i.e., hawks and owls) selecting riparian woodland for their nests. Nest survival declined with proximity to superpredator nesting sites. Overall, our study demonstrates how landscape structure and superior predators shapes predation risk for subordinate predators. Our results emphasize the importance of spatial heterogeneity in presenting opportunities for subordinate predators to coexist in a landscape with important superpredators.

Nested polymerase chain reaction (PCR) targeting 16S rDNA for bacterial identification in empyema.

PubMed

Prasad, Rajniti; Kumari, Chhaya; Das, B K; Nath, Gopal

2014-05-01

Empyema in children causes significant morbidity and mortality. However, identification of organisms is a major concern. To detect bacterial pathogens in pus specimens of children with empyema by 16S rDNA nested polymerase chain reaction (PCR) and correlate it with culture and sensitivity. Sixty-six children admitted to the paediatric ward with a diagnosis of empyema were enrolled prospectively. Aspirated pus was subjected to cytochemical examination, culture and sensitivity, and nested PCR targeting 16S rDNA using a universal eubacterial primer. Mean (SD) age was 5·8 (1·8) years (range 1-13). Analysis of aspirated pus demonstrated total leucocyte count >1000×10(6)/L, elevated protein (≧20 g/L) and decreased glucose (≤2·2 mmol/L) in 80·3%, 98·5% and 100%, respectively. Gram-positive cocci were detected in 29 (43·9%) and Gram-negative bacilli in two patients. Nested PCR for the presence of bacterial pathogens was positive in 50·0%, compared with 36·3% for culture. 16S rDNA PCR improves rates of detection of bacteria in pleural fluid, and can detect bacterial species in a single assay as well as identifying unusual and unexpected causal agents.

Extremes of heat, drought and precipitation depress reproductive performance in shortgrass prairie passerines

USGS Publications Warehouse

Conrey, Reesa Y.; Skagen, Susan K.; Yackel, Amy; Panjabi, Arvind O.

2016-01-01

Climate change elevates conservation concerns worldwide because it is likely to exacerbate many identified threats to animal populations. In recent decades, grassland birds have declined faster than other North American bird species, a loss thought to be due to habitat loss and fragmentation and changing agricultural practices. Climate change poses additional threats of unknown magnitude to these already declining populations. We examined how seasonal and daily weather conditions over 10 years influenced nest survival of five species of insectivorous passerines native to the shortgrass prairie and evaluate our findings relative to future climate predictions for this region. Daily nest survival (n = 870) was best predicted by a combination of daily and seasonal weather variables, age of nest, time in season and bird habitat guild. Within a season, survival rates were lower on very hot days (temperatures ≥ 35 °C), on dry days (with a lag of 1 day) and on stormy days (especially for those species nesting in shorter vegetation). Across years, survival rates were also lower during warmer and drier breeding seasons. Clutch sizes were larger when early spring temperatures were cool and the week prior to egg-laying was wetter and warming. Climate change is likely to exacerbate grassland bird population declines because projected climate conditions include rising temperatures, more prolonged drought and more intense storms as the hydrological cycle is altered. Under varying realistic scenarios, nest success estimates were halved compared to their current average value when models both increased the temperature (3 °C) and decreased precipitation (two additional dry days during a nesting period), thus underscoring a sense of urgency in identifying and addressing the current causes of range-wide declines.

Assessing species habitat using Google Street View: a case study of cliff-nesting vultures.

PubMed

Olea, Pedro P; Mateo-Tomás, Patricia

2013-01-01

The assessment of a species' habitat is a crucial issue in ecology and conservation. While the collection of habitat data has been boosted by the availability of remote sensing technologies, certain habitat types have yet to be collected through costly, on-ground surveys, limiting study over large areas. Cliffs are ecosystems that provide habitat for a rich biodiversity, especially raptors. Because of their principally vertical structure, however, cliffs are not easy to study by remote sensing technologies, posing a challenge for many researches and managers working with cliff-related biodiversity. We explore the feasibility of Google Street View, a freely available on-line tool, to remotely identify and assess the nesting habitat of two cliff-nesting vultures (the griffon vulture and the globally endangered Egyptian vulture) in northwestern Spain. Two main usefulness of Google Street View to ecologists and conservation biologists were evaluated: i) remotely identifying a species' potential habitat and ii) extracting fine-scale habitat information. Google Street View imagery covered 49% (1,907 km) of the roads of our study area (7,000 km²). The potential visibility covered by on-ground surveys was significantly greater (mean: 97.4%) than that of Google Street View (48.1%). However, incorporating Google Street View to the vulture's habitat survey would save, on average, 36% in time and 49.5% in funds with respect to the on-ground survey only. The ability of Google Street View to identify cliffs (overall accuracy = 100%) outperformed the classification maps derived from digital elevation models (DEMs) (62-95%). Nonetheless, high-performance DEM maps may be useful to compensate Google Street View coverage limitations. Through Google Street View we could examine 66% of the vultures' nesting-cliffs existing in the study area (n = 148): 64% from griffon vultures and 65% from Egyptian vultures. It also allowed us the extraction of fine-scale features of cliffs. This World Wide Web-based methodology may be a useful, complementary tool to remotely map and assess the potential habitat of cliff-dependent biodiversity over large geographic areas, saving survey-related costs.

Assessing Species Habitat Using Google Street View: A Case Study of Cliff-Nesting Vultures

PubMed Central

Olea, Pedro P.; Mateo-Tomás, Patricia

2013-01-01

The assessment of a species’ habitat is a crucial issue in ecology and conservation. While the collection of habitat data has been boosted by the availability of remote sensing technologies, certain habitat types have yet to be collected through costly, on-ground surveys, limiting study over large areas. Cliffs are ecosystems that provide habitat for a rich biodiversity, especially raptors. Because of their principally vertical structure, however, cliffs are not easy to study by remote sensing technologies, posing a challenge for many researches and managers working with cliff-related biodiversity. We explore the feasibility of Google Street View, a freely available on-line tool, to remotely identify and assess the nesting habitat of two cliff-nesting vultures (the griffon vulture and the globally endangered Egyptian vulture) in northwestern Spain. Two main usefulness of Google Street View to ecologists and conservation biologists were evaluated: i) remotely identifying a species’ potential habitat and ii) extracting fine-scale habitat information. Google Street View imagery covered 49% (1,907 km) of the roads of our study area (7,000 km2). The potential visibility covered by on-ground surveys was significantly greater (mean: 97.4%) than that of Google Street View (48.1%). However, incorporating Google Street View to the vulture’s habitat survey would save, on average, 36% in time and 49.5% in funds with respect to the on-ground survey only. The ability of Google Street View to identify cliffs (overall accuracy = 100%) outperformed the classification maps derived from digital elevation models (DEMs) (62–95%). Nonetheless, high-performance DEM maps may be useful to compensate Google Street View coverage limitations. Through Google Street View we could examine 66% of the vultures’ nesting-cliffs existing in the study area (n = 148): 64% from griffon vultures and 65% from Egyptian vultures. It also allowed us the extraction of fine-scale features of cliffs. This World Wide Web-based methodology may be a useful, complementary tool to remotely map and assess the potential habitat of cliff-dependent biodiversity over large geographic areas, saving survey-related costs. PMID:23355880

Coevolutionary diversification creates nested-modular structure in phage–bacteria interaction networks

PubMed Central

Beckett, Stephen J.; Williams, Hywel T. P.

2013-01-01

Phage and their bacterial hosts are the most diverse and abundant biological entities in the oceans, where their interactions have a major impact on marine ecology and ecosystem function. The structure of interaction networks for natural phage–bacteria communities offers insight into their coevolutionary origin. At small phylogenetic scales, observed communities typically show a nested structure, in which both hosts and phages can be ranked by their range of resistance and infectivity, respectively. A qualitatively different multi-scale structure is seen at larger phylogenetic scales; a natural assemblage sampled from the Atlantic Ocean displays large-scale modularity and local nestedness within each module. Here, we show that such ‘nested-modular’ interaction networks can be produced by a simple model of host–phage coevolution in which infection depends on genetic matching. Negative frequency-dependent selection causes diversification of hosts (to escape phages) and phages (to track their evolving hosts). This creates a diverse community of bacteria and phage, maintained by kill-the-winner ecological dynamics. When the resulting communities are visualized as bipartite networks of who infects whom, they show the nested-modular structure characteristic of the Atlantic sample. The statistical significance and strength of this observation varies depending on whether the interaction networks take into account the density of the interacting strains, with implications for interpretation of interaction networks constructed by different methods. Our results suggest that the apparently complex community structures associated with marine bacteria and phage may arise from relatively simple coevolutionary origins. PMID:24516719

Waterbird nest-site selection is influenced by neighboring nests and island topography

USGS Publications Warehouse

Hartman, Christopher; Ackerman, Joshua T.; Takekawa, John Y.; Herzog, Mark

2016-01-01

Avian nest-site selection is influenced by factors operating across multiple spatial scales. Identifying preferred physical characteristics (e.g., topography, vegetation structure) can inform managers to improve nesting habitat suitability. However, social factors (e.g., attraction, territoriality, competition) can complicate understanding physical characteristics preferred by nesting birds. We simultaneously evaluated the physical characteristics and social factors influencing selection of island nest sites by colonial-nesting American avocets (Recurvirostra americana) and Forster's terns (Sterna forsteri) at 2 spatial scales in San Francisco Bay, 2011–2012. At the larger island plot (1 m2) scale, we used real-time kinematics to produce detailed topographies of nesting islands and map the distribution of nests. Nesting probability was greatest in island plots between 0.5 m and 1.5 m above the water surface, at distances <10 m from the water's edge, and of moderately steep (avocets) or flat (terns) slopes. Further, avocet and tern nesting probability increased as the number of nests initiated in adjacent plots increased up to a peak of 11–12 tern nests, and then decreased thereafter. Yet, avocets were less likely to nest in plots adjacent to plots with nesting avocets, suggesting an influence of intra-specific territoriality. At the smaller microhabitat scale, or the area immediately surrounding the nest, we compared topography, vegetation, and distance to nearest nest between nest sites and paired random sites. Topography had little influence on selection of the nest microhabitat. Instead, nest sites were more likely to have vegetation present, and greater cover, than random sites. Finally, avocet, and to a lesser extent tern, nest sites were closer to other active conspecific or heterospecific nests than random sites, indicating that social attraction played a role in selection of nest microhabitat. Our results demonstrate key differences in nest-site selection between co-occurring avocets and terns, and indicate the effects of physical characteristics and social factors on selection of nesting habitat are dependent on the spatial scale examined. Moreover, these results indicate that islands with abundant area between 0.5 m and 1.5 m above the water surface, within 10 m of the water's edge, and containing a mosaic of slopes ranging from flat to moderately steep would provide preferred nesting habitat for avocets and terns. © 2016 The Wildlife Society.

How does vegetation structure influence woodpeckers and secondary cavity nesting birds in African cork oak forest?

NASA Astrophysics Data System (ADS)

Segura, Amalia

2017-08-01

The Great Spotted Woodpecker provides important information about the status of a forest in terms of structure and age. As a primary cavity creator, it provides small-medium size cavities for passerines. However, despite its interest as an ecosystem engineer, studies of this species in Africa are scarce. Here, spatially explicit predictive models were used to investigate how forest structural variables are related to both the Great Spotted Woodpecker and secondary cavity nesting birds in Maamora cork oak forest (northwest Morocco). A positive association between Great Spotted Woodpecker and both dead-tree density and large mature trees (>60 cm dbh) was found. This study area, Maamora, has an old-growth forest structure incorporating a broad range of size and condition of live and dead trees, favouring Great Spotted Woodpecker by providing high availability of foraging and excavating sites. Secondary cavity nesting birds, represented by Great Tit, African Blue Tit, and Hoopoe, were predicted by Great Spotted Woodpecker detections. The findings suggest that the conservation of the Maamora cork oak forest could be key to maintaining these hole-nesting birds. However, this forest is threatened by forestry practises and livestock overgrazing and the challenge is therefore to find sustainable management strategies that ensure conservation while allowing its exploitation.

Effects of Seasonal Weather on Breeding Phenology and Reproductive Success of Alpine Ptarmigan in Colorado

PubMed Central

Wann, Gregory T.; Aldridge, Cameron L.; Braun, Clait E.

2016-01-01

Animal populations occurring at high elevations are often assumed to be in peril of extinctions or local extirpations due to elevational-dispersal limitations and thermoregulatory constraints as habitats change and warm. However, long-term monitoring of high-elevation populations is uncommon relative to those occurring at lower elevations, and evidence supporting this assumption is limited. We analyzed 45 years of reproductive data for two Colorado populations of white-tailed ptarmigan (Lagopus leucura), an alpine-endemic species with restricted distribution in western North America. Seasonal temperatures measured by the number of growing degree days warmed significantly at our study sites for pre-nesting, nesting, and brood-rearing seasonal periods (mean advance of 8 growing degree days per decade), and both populations advanced their reproductive phenology over the study period based on median hatch dates (median advance of 3.7 and 1.9 days per decade for the northern and southern sites, respectively). Reproductive performance measured by the number of chicks per hen declined significantly at one study site but not the other, and differences between sites may have been due to habitat degradation at one study area. Annual variability in chicks per hen was large at both sites but only weakly related to seasonal weather. An index of precipitation and temperature during the brood-rearing period was the best predictor for reproductive success with warm and dry conditions relating positively to number of chicks per hen. Our results provide evidence for two alpine ptarmigan populations that are remarkably invariant to fluctuations in seasonal weather with respect to reproductive success as measured by number of chicks per hen in the breeding population. These results are surprising given the general perception of alpine animal populations as being highly sensitive to warming temperatures. PMID:27420478

Effects of Seasonal Weather on Breeding Phenology and Reproductive Success of Alpine Ptarmigan in Colorado.

PubMed

Wann, Gregory T; Aldridge, Cameron L; Braun, Clait E

2016-01-01

Animal populations occurring at high elevations are often assumed to be in peril of extinctions or local extirpations due to elevational-dispersal limitations and thermoregulatory constraints as habitats change and warm. However, long-term monitoring of high-elevation populations is uncommon relative to those occurring at lower elevations, and evidence supporting this assumption is limited. We analyzed 45 years of reproductive data for two Colorado populations of white-tailed ptarmigan (Lagopus leucura), an alpine-endemic species with restricted distribution in western North America. Seasonal temperatures measured by the number of growing degree days warmed significantly at our study sites for pre-nesting, nesting, and brood-rearing seasonal periods (mean advance of 8 growing degree days per decade), and both populations advanced their reproductive phenology over the study period based on median hatch dates (median advance of 3.7 and 1.9 days per decade for the northern and southern sites, respectively). Reproductive performance measured by the number of chicks per hen declined significantly at one study site but not the other, and differences between sites may have been due to habitat degradation at one study area. Annual variability in chicks per hen was large at both sites but only weakly related to seasonal weather. An index of precipitation and temperature during the brood-rearing period was the best predictor for reproductive success with warm and dry conditions relating positively to number of chicks per hen. Our results provide evidence for two alpine ptarmigan populations that are remarkably invariant to fluctuations in seasonal weather with respect to reproductive success as measured by number of chicks per hen in the breeding population. These results are surprising given the general perception of alpine animal populations as being highly sensitive to warming temperatures.

Effects of seasonal weather on breeding phenology and reproductive success of alpine ptarmigan in Colorado

USGS Publications Warehouse

Wann, Greg; Aldridge, Cameron L.; Braun, Clait E.

2016-01-01

Animal populations occurring at high elevations are often assumed to be in peril of extinctions or local extirpations due to elevational-dispersal limitations and thermoregulatory constraints as habitats change and warm. However, long-term monitoring of high-elevation populations is uncommon relative to those occurring at lower elevations, and evidence supporting this assumption is limited. We analyzed 45 years of reproductive data for two Colorado populations of white-tailed ptarmigan (Lagopus leucura), an alpine-endemic species with restricted distribution in western North America. Seasonal temperatures measured by the number of growing degree days warmed significantly at our study sites for pre-nesting, nesting, and brood-rearing seasonal periods (mean advance of 8 growing degree days per decade), and both populations advanced their reproductive phenology over the study period based on median hatch dates (median advance of 3.7 and 1.9 days per decade for the northern and southern sites, respectively). Reproductive performance measured by the number of chicks per hen declined significantly at one study site but not the other, and differences between sites may have been due to habitat degradation at one study area. Annual variability in chicks per hen was large at both sites but only weakly related to seasonal weather. An index of precipitation and temperature during the brood-rearing period was the best predictor for reproductive success with warm and dry conditions relating positively to number of chicks per hen. Our results provide evidence for two alpine ptarmigan populations that are remarkably invariant to fluctuations in seasonal weather with respect to reproductive success as measured by number of chicks per hen in the breeding population. These results are surprising given the general perception of alpine animal populations as being highly sensitive to warming temperatures.

Soil attributes drive nest-site selection by the campo miner Geositta poeciloptera.

PubMed

Meireles, Ricardo Camargos de; Teixeira, João Paulo Gusmão; Solar, Ricardo; Vasconcelos, Bruno Nery F; Fernandes, Raphael B A; Lopes, Leonardo Esteves

2018-01-01

Substrate type is a key-factor in nest-site selection and nest architecture of burrowing birds. However, little is known about which factors drive nest-site selection for these species, especially in the tropics. We studied the influence of soil attributes on nest-site selection by the campo miner Geositta poeciloptera, an open grassland bird that builds its nests within soil cavities. For all nests found, we measured the depth of the nest cavity and the resistance of the soil to penetration, and identified the soil horizon in which the nest was located. In soil banks with nests, we collected soil samples for granulometric analysis around each nest cavity, while in soil banks without nests we collected these samples at random points. From 43 nests found, 86% were located in the deeper soil horizons (C-horizon), and only 14% in the shallower horizons (B-horizon). Granulometric analysis showed that the C-horizons possessed a high similar granulometric composition, with high silt and low clay contents. These characteristics are associated with a low degree of structural development of the soil, which makes it easier to excavate. Contrarily, soil resistance to penetration does not seem to be an important criterion for nest site selection, although nests in more resistant the soils tend to have shallower nest cavities. Among the soil banks analyzed, 40% of those without cavities possessed a larger proportion of B-horizon relative to the C-horizon, and their texture was more clayey. On the other hand, almost all soil banks containing nest cavities had a larger C-horizon and a silty texture, indicating that soil attributes drive nest-site selection by G. poeciloptera. Thus, we conclude that the patchy distribution of G. poeciloptera can attributed to the infrequent natural exposure of the C-horizon in the tropical region, where well developed, deep and permeable soils are more common.

Soil attributes drive nest-site selection by the campo miner Geositta poeciloptera

PubMed Central

Teixeira, João Paulo Gusmão; Solar, Ricardo; Vasconcelos, Bruno Nery F.; Fernandes, Raphael B. A.; Lopes, Leonardo Esteves

2018-01-01

Substrate type is a key-factor in nest-site selection and nest architecture of burrowing birds. However, little is known about which factors drive nest-site selection for these species, especially in the tropics. We studied the influence of soil attributes on nest-site selection by the campo miner Geositta poeciloptera, an open grassland bird that builds its nests within soil cavities. For all nests found, we measured the depth of the nest cavity and the resistance of the soil to penetration, and identified the soil horizon in which the nest was located. In soil banks with nests, we collected soil samples for granulometric analysis around each nest cavity, while in soil banks without nests we collected these samples at random points. From 43 nests found, 86% were located in the deeper soil horizons (C-horizon), and only 14% in the shallower horizons (B-horizon). Granulometric analysis showed that the C-horizons possessed a high similar granulometric composition, with high silt and low clay contents. These characteristics are associated with a low degree of structural development of the soil, which makes it easier to excavate. Contrarily, soil resistance to penetration does not seem to be an important criterion for nest site selection, although nests in more resistant the soils tend to have shallower nest cavities. Among the soil banks analyzed, 40% of those without cavities possessed a larger proportion of B-horizon relative to the C-horizon, and their texture was more clayey. On the other hand, almost all soil banks containing nest cavities had a larger C-horizon and a silty texture, indicating that soil attributes drive nest-site selection by G. poeciloptera. Thus, we conclude that the patchy distribution of G. poeciloptera can attributed to the infrequent natural exposure of the C-horizon in the tropical region, where well developed, deep and permeable soils are more common. PMID:29381768

Density and success of bird nests relative to grazing on western Montana grasslands

USGS Publications Warehouse

Fondell, Thomas F.; Ball, I.J.

2004-01-01

Grassland birds are declining at a faster rate than any other group of North American bird species. Livestock grazing is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on grazed and ungrazed grasslands in western Montana. In comparison to grazed plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occurred where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to grazing reflected the effect of grazing on availability of nest sites. Nest success was similar between grazed plots and ungrazed plots for two species but was lower for nests on grazed plots than on ungrazed plots for two other species because of increased rates of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or grazed plots (one species), precluding evaluation of the effects of grazing on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that grazing altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that grazing directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid intensive grazing during the breeding season would be expected to benefit many grassland bird species.

Extraction and representation of nested catchment areas from digital elevation models in lake-dominated topography

NASA Astrophysics Data System (ADS)

Mackay, D. Scott; Band, Lawrence E.

1998-04-01

This paper presents a new method for extracting flow directions, contributing (upslope) areas, and nested catchments from digital elevation models in lake-dominated areas. Existing tools for acquiring descriptive variables of the topography, such as surface flow directions and contributing areas, were developed for moderate to steep topography. These tools are typically difficult to apply in gentle topography owing to limitations in explicitly handling lakes and other flat areas. This paper addresses the problem of accurately representing general topographic features by first identifying distinguishing features, such as lakes, in gentle topography areas and then using these features to guide the search for topographic flow directions and catchment marking. Lakes are explicitly represented in the topology of a watershed for use in water routing. Nonlake flat features help guide the search for topographic flow directions in areas of low signal to noise. This combined feature-based and grid-based search for topographic features yields improved contributing areas and watershed boundaries where there are lakes and other flat areas. Lakes are easily classified from remotely sensed imagery, which makes automated representation of lakes as subsystems within a watershed system tractable with widely available data sets.

Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation.

PubMed

Geib, Jennifer C; Strange, James P; Galenj, Candace

2015-04-01

Recent reports of global declines in pollinator species imply an urgent need to assess the abundance of native pollinators and density-dependent benefits for linked plants. In this study, we investigated (1) pollinator nest distributions and estimated colony abundances, (2) the relationship between abundances of foraging workers and the number of nests they represent, (3) pollinator foraging ranges, and (4) the relationship between pollinator abundance and plant reproduction. We examined these questions in an alpine ecosystem in the Colorado Rocky Mountains, focusing on four alpine bumble bee species (Bombus balteatus, B. flavifrons, B. bifarius, and B. sylvicola), and two host plants that differ in their degrees of pollinator specialization (Trifolium dasyphyllum and T. parryi). Using microsatellites, we found that estimated colony abundances among Bombus species ranged from ~18 to 78 colonies/0.01 km2. The long-tongued species B. balteatus was most common, especially high above treeline, but the subalpine species B. bifarius was unexpectedly abundant for this elevation range. Nests detected among sampled foragers of each species were correlated with the number of foragers caught. Foraging ranges were smaller than expected for all Bombus species, ranging from 25 to 110 m. Fruit set for the specialized plant, Trifolium parryi, was positively related to the abundance of its Bombus pollinator. In contrast, fruit set for the generalized plant, T. dasyphyllum, was related to abundance of all Bombus species. Because forager abundance was related to nest abundance of each Bombus species and was an equally effective predictor of plant fecundity, forager inventories are probably suitable for assessing the health of outcrossing plant populations. However, nest abundance, rather than forager abundance, better reflects demographic and genetic health in populations of eusocial pollinators such as bumble bees. Development of models incorporating the parameters we have measured here (nest abundance, forager abundance, and foraging distance) could increase the usefulness of foraging worker inventories in nionitoring, managing, and conserving pollinator populations.

Response of roseate tern to a shoreline protection project on Falkner Island, Connecticut

USGS Publications Warehouse

Rogers, C.J.; Spendelow, J.A.; Guilfoyle, Michael P.; Fischer, Richard A.; Pashley, David N.; Lott, Casey A.

2007-01-01

Construction was initiated following the 2000 tern breeding season for Phase 1 of a planned two-phase ?Shoreline Protection and Erosion Control Project? at the Falkner Island Unit of the USFWS Stewart B. McKinney National Wildlife Refuge located in Long Island Sound off the coast of Guilford, CT. When the Common Tern (Sterna hirundo) and federally endangered Roseate Tern (S. dougallii) arrived in spring 2001, they encountered several major habitat changes from what had existed in previous years. These changes included: a rock revetment covering most of the former nesting habitat on the beach from the northwestern section around the northern tip and covering about 60% of the eastern side; an elevated 60- ? 4-m shelf covering the beach and lower bank of the southwestern section; and about 2,000 sq m of devegetated areas on top of the island on the northeast side above the revetment, and about one-third of the southern half of the island. The southwest shelf was created by bulldozing and compacting extra construction fill and in situ materials. This shelf differed in internal structure from the main revetment on the north and eastern sections of the island because it lacked the deep internal crevices of the revetment. The deep internal crevices were created from the large stones and boulders (up to 2 tons) used in the construction of the main revetment. Small rock and gravel was used to fill the crevices to within 3 feet (0.9 m) of the surface of the revetment. Because half-buried tires and nest boxes for the six Roseate Tern (Sterna dougallii) sub-colony areas were deployed in similar patterns on the remaining beach, and nest boxes were placed on the newly elevated shelf areas several meters above previous locations on the now-covered beach areas, the distribution of Roseate Tern nests did not change much from 2000 to 2001. However, the movements of Roseate Tern chicks ? in many cases led by their parents towards traditional hiding places ? into the labyrinth of subterranean channels, especially in the main revetment area, made it difficult to measure chick growth and productivity as had been done for more than 12 years prior to construction. Also, observations of color-banded adults that were unable to locate and feed their young inside the main revetment, and of adults returning to courtship behavior and renesting after having hatched chicks from their initial clutches, indicated that a minimum of 20% of the chicks (mostly first hatched A-chicks, which usually have high rates of survival to fledging) that entered the main revetment died after doing so in 2001. The mortality rate of Roseate Tern chicks that entered the secondary revetment on the southwest shelf, however, was not unusually high in 2001. In an attempt to reduce the likelihood of nesting and chick losses in these sub-colonies, a research team led by the USGS in 2002-2003 did not put nest boxes on the northeast and east shelf areas where previous losses had been high. However, losses of tern eggs and young chicks to predatory Black-crowned Night Herons (Nycticorax nycticorax) were so great in 2002?2003 that few Roseate Tern chicks survived long enough to move into the main revetment area and little comparative survival data were collected. The USFWS continues to remove predatory night herons, to monitor the location and success of nesting Roseate Terns and to fill in some of problem areas near the tern nests in the main revetment. The extensive chick-searching fieldwork and observational procedures used by the USGS-led research team to determine the growth and survival of the Roseate Tern chicks at Falkner Island were not used in 2004?2005. The number of chicks lost in the revetment during these years is not known. Without additional fill, loss of chicks of this endangered species in the main revetment may rise again even though the night heron predation problem has been reduced.

Green-tailed Towhee response to prescribed fire in montane shrubland

USGS Publications Warehouse

Jehle, G.; Savidge, J.A.; Kotliar, N.B.

2006-01-01

Fire alters the structure and composition of shrublands and affects habitat quality for the associated avifauna. Because shrubland ecosystems have been greatly reduced from their original extent in western North America and fire is increasingly being used to manage these landscapes, a better understanding of how fire affects the associated vegetation and wildlife is imperative. We evaluated the response of Green-tailed Towhees (Pipilo chlorurus) to prescribed fire in the montane shrublands of Rocky Mountain National Park, Colorado during 2002 and 2003. Three to five years following prescribed burning, Green-tailed Towhee density and shrub cover were generally higher in unburned areas. Nests (n = 179) were located in unburned vegetation; within burned sites, all nests were in remnant patches. Green-tailed Towhee nest survival was 57% (95% CI = 49%-65%) across the two years of the study. More than half of the nests were in common juniper (Juniperus communis) shrubs, and nest survival was higher for nests in junipers than those in other shrub species. Daily nest survival rates were lower at the site with the highest density of towhees and declined over the breeding season. With regard to shrub cover, opposite trends were observed for nest-site selection and nest survival: nest plots had greater shrub cover than non-nest plots, but nest survival decreased with increasing shrub cover. Because shrub cover affects towhee density and nest survival in conflicting ways, fire management at Rocky Mountain National Park alters both habitat availability and suitability for Green-tailed Towhees. ?? The Cooper Ornithological Society 2006.

Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs.

PubMed

Tanaka, Kohei; Zelenitsky, Darla K; Therrien, François

2015-01-01

Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests with fully exposed eggs only became widespread among Euornithes. A potential co-evolution of open nests and brooding behavior among maniraptorans may have freed theropods from the ground-based restrictions inherent to covered nests and allowed the exploitation of alternate nesting locations. These changes in nesting styles and behaviors thus may have played a role in the evolutionary success of maniraptorans (including birds).

Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs

PubMed Central

2015-01-01

Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests with fully exposed eggs only became widespread among Euornithes. A potential co-evolution of open nests and brooding behavior among maniraptorans may have freed theropods from the ground-based restrictions inherent to covered nests and allowed the exploitation of alternate nesting locations. These changes in nesting styles and behaviors thus may have played a role in the evolutionary success of maniraptorans (including birds). PMID:26605799

Phylogenetic analysis of honey bee behavioral evolution.

PubMed

Raffiudin, Rika; Crozier, Ross H

2007-05-01

DNA sequences from three mitochondrial (rrnL, cox2, nad2) and one nuclear gene (itpr) from all 9 known honey bee species (Apis), a 10th possible species, Apis dorsata binghami, and three outgroup species (Bombus terrestris, Melipona bicolor and Trigona fimbriata) were used to infer Apis phylogenetic relationships using Bayesian analysis. The dwarf honey bees were confirmed as basal, and the giant and cavity-nesting species to be monophyletic. All nodes were strongly supported except that grouping Apis cerana with A. nigrocincta. Two thousand post-burnin trees from the phylogenetic analysis were used in a Bayesian comparative analysis to explore the evolution of dance type, nest structure, comb structure and dance sound within Apis. The ancestral honey bee species was inferred with high support to have nested in the open, and to have more likely than not had a silent vertical waggle dance and a single comb. The common ancestor of the giant and cavity-dwelling bees is strongly inferred to have had a buzzing vertical directional dance. All pairwise combinations of characters showed strong association, but the multiple comparisons problem reduces the ability to infer associations between states between characters. Nevertheless, a buzzing dance is significantly associated with cavity-nesting, several vertical combs, and dancing vertically, a horizontal dance is significantly associated with a nest with a single comb wrapped around the support, and open nesting with a single pendant comb and a silent waggle dance.

Unique crystal structure of a novel surfactant protein from the foam nest of the frog Leptodactylus vastus.

PubMed

Cavalcante Hissa, Denise; Arruda Bezerra, Gustavo; Birner-Gruenberger, Ruth; Paulino Silva, Luciano; Usón, Isabel; Gruber, Karl; Maciel Melo, Vânia Maria

2014-02-10

Breeding by releasing eggs into stable biofoams ("foam nests") is a peculiar reproduction mode within anurans, fish, and tunicates; not much is known regarding the biochemistry or molecular mechanisms involved. Lv-ranaspumin (Lv-RSN-1) is the predominant protein from the foam nest of the frog Leptodactylus vastus. This protein shows natural surfactant activity, which is assumed to be crucial for stabilizing foam nests. We elucidated the amino acid sequence of Lv-RSN-1 by de novo sequencing with mass-spectrometry and determined the high-resolution X-ray structure of the protein. It has a unique fold mainly composed of a bundle of 11 α-helices and two small antiparallel β-strands. Lv-RSN-1 has a surface rich in hydrophilic residues and a lipophilic cavity in the region of the antiparallel β-sheet. It possesses intrinsic surface-active properties, reducing the surface tension of water from 73 to 61 mN m(-1) (15 μg mL(-1)). Lv-RSN-1 belongs to a new class of surfactants proteins for which little has been reported regarding structure or function. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantitative analysis of American woodcock nest and brood habitat

USGS Publications Warehouse

Bourgeois, A.; Keppie, Daniel M.; Owen, Ray B.

1977-01-01

Sixteen nest and 19 brood sites of American woodcock (Philohela minoI) were examined in northern lower Michigan between 15 April and 15 June 1974 to determine habitat structure associated with these sites. Woodcock hens utilized young, second-growth forest stands which were similar in species composition for both nesting and brood rearing. A multi-varIate discriminant function analysis revealed a significant (P< 0.05) difference, however, in habitat structure. Nest habitat was characterized by lower tree density (2176 trees/ha) and basal area (8.6 m2/ha), by being close to forest openings (7 m) and by being situated on dry, relatively well drained sites. In contrast, woodcock broods were located in sites that had nearly twice the tree density (3934 trees/hal and basal area (16.5 m2/ha), was located over twice as far from forest openings (18 m) and generally occurred on damp sites, near (8 m) standing water. Importance of the habitat features to the species and possible management implications are discussed.

Facultative cardiac responses to regional hypoxia in lizard embryos.

PubMed

Du, Wei-Guo; Thompson, Michael B; Shine, Richard

2010-08-01

In natural nests, the eggs of squamate reptiles (lizards and snakes) sometimes experience unpredictable shifts in oxygen availability as a function of nest flooding, or the details of egg location within a nest. We experimentally investigated whether embryos can facultatively adjust cardiac function to cope with such challenges by imposing regional hypoxia on developing eggs of the scincid lizard Bassiana duperreyi. To do so, we sealed half of the eggshell surface with tissue adhesive. The embryos rapidly responded by increasing heart rates, which they maintained for long periods. The elevated heart rates enabled the embryos not only to survive, but to maintain "normal" metabolic rates, and to hatch at the usual time with unmodified phenotypic traits (e.g., hatchling size, relative heart mass, locomotor speed, post-hatchling survival and growth rates). Turtles and birds with rigid (highly calcified) eggshells show more dramatic ill-effects from hypoxic incubation, suggesting that the thin (and thus, highly gas-permeable) parchment-shelled eggs of most squamates allow more effective embryonic adjustment of oxygen exchange rates in response to externally-imposed hypoxia. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Fibroblast growth factor-10 signals development of von Brunn's nests in the exstrophic bladder

PubMed Central

Eastman, Rocky; Leaf, Elizabeth M.; Zhang, Dianzhong; True, Lawrence D.; Sweet, Robert M.; Seidel, Kristy; Siebert, Joseph R.; Grady, Richard; Mitchell, Michael E.

2010-01-01

von Brunn's nests have long been recognized as precursors of benign lesions of the urinary bladder mucosa. We report here that von Brunn's nests are especially prevalent in the exstrophic bladder, a birth defect that predisposes the patient to formation of bladder cancer. Cells of von Brunn's nest were found to coalesce into a stratified, polarized epithelium which surrounds itself with a capsule-like structure rich in types I, III, and IV collagen. Histocytochemical analysis and keratin profiling demonstrated that nested cells exhibited a phenotype similar, but not identical, to that of urothelial cells of transitional epithelium. Immunostaining and in situ hybridization analysis of exstrophic tissue demonstrated that the FGF-10 receptor is synthesized and retained by cells of von Brunn's nest. In contrast, FGF-10 is synthesized and secreted by mesenchymal fibroblasts via a paracrine pathway that targets basal epithelial cells of von Brunn's nests. Small clusters of 10pRp cells, positive for both FGF-10 and its receptor, were observed both proximal to and inside blood vessels in the lamina propria. The collective evidence points to a mechanism where von Brunn's nests develop under the control of the FGF-10 signal transduction system and suggests that 10pRp cells may be the original source of nested cells. PMID:20719973

Nested high-resolution large-eddy simulations in WRF to support wind power

NASA Astrophysics Data System (ADS)

Mirocha, J.; Kirkil, G.; Kosovic, B.; Lundquist, J. K.

2009-12-01

The WRF model’s grid nesting capability provides a potentially powerful framework for simulating flow over a wide range of scales. One such application is computation of realistic inflow boundary conditions for large eddy simulations (LES) by nesting LES domains within mesoscale domains. While nesting has been widely and successfully applied at GCM to mesoscale resolutions, the WRF model’s nesting behavior at the high-resolution (Δx < 1000m) end of the spectrum is less well understood. Nesting LES within msoscale domains can significantly improve turbulent flow prediction at the scale of a wind park, providing a basis for superior site characterization, or for improved simulation of turbulent inflows encountered by turbines. We investigate WRF’s grid nesting capability at high mesh resolutions using nested mesoscale and large-eddy simulations. We examine the spatial scales required for flow structures to equilibrate to the finer mesh as flow enters a nest, and how the process depends on several parameters, including grid resolution, turbulence subfilter stress models, relaxation zones at nest interfaces, flow velocities, surface roughnesses, terrain complexity and atmospheric stability. Guidance on appropriate domain sizes and turbulence models for LES in light of these results is provided This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 LLNL-ABS-416482

Predation as a landscape effect: the trading off by prey species between predation risks and protection benefits.

PubMed

Mönkkönen, M; Husby, M; Tornberg, R; Helle, P; Thomson, R L

2007-05-01

1. Predators impose costs on their prey but may also provide benefits such as protection against other (e.g. nest) predators. The optimal breeding location in relation to the distance from a nesting raptor varies so as to minimize the sum of costs of adult and nest predation. We provide a conceptual model to account for variation in the relative predation risks and derive qualitative predictions for how different prey species should respond to the distance from goshawk Accipiter gentilis nests. 2. We test the model predictions using a comprehensive collection of data from northern Finland and central Norway. First, we carried out a series of experiments with artificial bird nests to test if goshawks may provide protection against nest predation. Second, we conducted standard bird censuses and nest-box experiments to detect how the density or territory occupancy of several prey species varies with distance from the nearest goshawk nest. 3. Nest predation rate increased with distance from goshawk nest indicating that goshawks may provide protection for birds' nests against nest predation. Abundance (or probability of presence) of the main prey species of goshawks peaked at intermediate distances from goshawk nests, reflecting the trade-off. The abundance of small songbird species decreased with distance from goshawk nests. The goshawk poses little risk to small songbirds and they may benefit from goshawk proximity in protection against nest predation. Finally, no pattern with distance in pied flycatcher territory (nest box) occupation rate or the onset of egg-laying was detected. This is expected, as flycatchers neither suffer from marked nest predation risk nor are favoured goshawk prey. 4. Our results suggest that territory location in relation to the nest of a predator is a trade-off situation where adult birds weigh the risk of themselves being predated against the benefits accrued from increased nest survival. Prey species appear able to detect and measure alternative predation risks, and respond adaptively. From the prey perspective, the landscape is a mosaic of habitat patches the quality of which varies according to structural and floristic features, but also to the spatial distribution of predators.

Topology of Plant - Flower-Visitor Networks in a Tropical Mountain Forest: Insights on the Role of Altitudinal and Temporal Variation.

PubMed

Cuartas-Hernández, Sandra; Medel, Rodrigo

2015-01-01

Understanding the factors determining the spatial and temporal variation of ecological networks is fundamental to the knowledge of their dynamics and functioning. In this study, we evaluate the effect of elevation and time on the structure of plant-flower-visitor networks in a Colombian mountain forest. We examine the level of generalization of plant and animal species and the identity of interactions in 44 bipartite matrices obtained from eight altitudinal levels, from 2200 to 2900 m during eight consecutive months. The contribution of altitude and time to the overall variation in the number of plant (P) and pollinator (A) species, network size (M), number of interactions (I), connectance (C), and nestedness was evaluated. In general, networks were small, showed high connectance values and non-nested patterns of organization. Variation in P, M, I and C was better accounted by time than elevation, seemingly related to temporal variation in precipitation. Most plant and insect species were specialists and the identity of links showed a high turnover over months and at every 100 m elevation. The partition of the whole system into smaller network units allowed us to detect small-scale patterns of interaction that contrasted with patterns commonly described in cumulative networks. The specialized but erratic pattern of network organization observed in this tropical mountain suggests that high connectance coupled with opportunistic attachment may confer robustness to plant-flower-visitor networks occurring at small spatial and temporal units.

Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival

USGS Publications Warehouse

Grisham, Blake A.; Godar, Alixandra J.; Boal, Clint W.; Haukos, David A.

2016-01-01

The range of Lesser Prairie-Chickens (Tympanuchus pallidicinctus) spans 4 unique ecoregions along 2 distinct environmental gradients. The Sand Shinnery Oak Prairie ecoregion of the Southern High Plains of New Mexico and Texas is environmentally isolated, warmer, and more arid than the Short-Grass, Sand Sagebrush, and Mixed-Grass Prairie ecoregions in Colorado, Kansas, Oklahoma, and the northeast panhandle of Texas. Weather is known to influence Lesser Prairie-Chicken nest survival in the Sand Shinnery Oak Prairie ecoregion; regional variation may also influence nest microclimate and, ultimately, survival during incubation. To address this question, we placed data loggers adjacent to nests during incubation to quantify temperature and humidity distribution functions in 3 ecoregions. We developed a suite of a priori nest survival models that incorporated derived microclimate parameters and visual obstruction as covariates in Program MARK. We monitored 49 nests in Mixed-Grass, 22 nests in Sand Shinnery Oak, and 30 nests in Short-Grass ecoregions from 2010 to 2014. Our findings indicated that (1) the Sand Shinnery Oak Prairie ecoregion was hotter and drier during incubation than the Mixed- and Short-Grass ecoregions; (2) nest microclimate varied among years within ecoregions; (3) visual obstruction was positively associated with nest survival; but (4) daily nest survival probability decreased by 10% every half-hour when temperature was greater than 34°C and vapor pressure deficit was less than −23 mmHg during the day (about 0600–2100 hours). Our major finding confirmed microclimate thresholds for nest survival under natural conditions across the species' distribution, although Lesser Prairie-Chickens are more likely to experience microclimate conditions that result in nest failures in the Sand Shinnery Oak Prairie ecoregion. The species would benefit from identification of thermal landscapes and management actions that promote cooler, more humid nest microclimates.

Breeding biology and nest-site selection of red-tailed hawks in an altered desert grassland

USGS Publications Warehouse

Hobbs, R.J.; DeStefano, S.; Halvorson, W.L.

2006-01-01

Red-tailed Hawks (Buteo jamaicensis) have expanded their range as trees have invaded formerly-open grasslands. Desert grasslands of southern Arizona have been invaded by mesquite trees (Prosopis velutina) since Anglo-American settlement and now support a large population of Red-tailed Hawks. We studied a population of Red-tailed Hawks in an altered desert grassland in southern Arizona. Our objectives were to determine what environmental characteristics influence Red-tailed Hawk habitat selection in mesquite-invaded desert grasslands and to evaluate the habitat quality of these grasslands for Red-tailed Hawks based on nesting density, nest success, and productivity. Red-tailed Hawks had 86% (95% C.I. = 73-99) nest success and 1.82 young per breeding pair (95% C.I. = 1.41-2.23). Nesting density was 0.15 (95% CI = 0.08-0.21) breeding pairs/km2 and the mean nearest-neighbor distance was 1.95 km (95% C.I. = 1.74-2.16). Red-tailed Hawks selected nest-sites with taller nest-trees and greater tree height and cover than were available at random. Mesquite trees in desert grasslands provide abundant potential nesting structures for Red-tailed Hawks. ?? 2006 The Raptor Research Foundation, Inc.

A review of the nest protection hypothesis: does inclusion of fresh green plant material in birds' nests reduce parasite infestation?

PubMed

Scott-Baumann, James F; Morgan, Eric R

2015-07-01

The use of aromatic plants and their essential oils for ectoparasite treatment is a field of growing interest. Several species of birds regularly introduce aromatic herbs into their nests putatively to reduce parasites. The behaviour is most often seen in cavity nesting birds and after nest building has finished. The plants are included in a non-structural manner and are often strongly aromatic. Various different hypotheses have been proposed regarding the function of this behaviour; from the plants altering some non-living factor in the nest (crypsis, water loss and insulation hypotheses) to them being involved in mate selection (mate hypothesis) or even having a beneficial effect, direct or indirect, on chicks (drug or nest protection hypothesis, NPH). Many studies have been carried out over the years observing and experimentally testing these hypotheses. This review focuses on studies involving the most popular of these hypotheses, the NPH: that plants decrease nest parasites or pathogens, thereby conveying positive effects to the chicks, allowing the behaviour to evolve. Studies providing observational evidence towards this hypothesis and those experimentally testing it are discussed.

Brief communication: why sleep in a nest? Empirical testing of the function of simple shelters made by wild chimpanzees.

PubMed

Stewart, F A

2011-10-01

All great apes build nightly a structure ("nest" or "bed") that is assumed to function primarily as a sleeping-platform. However, several other nest function hypotheses have been proposed: antipredation, antipathogen, and thermoregulation. I tested these simple shelter functions of chimpanzee nests in an experiment for which I was the subject in Fongoli, Senegal. I slept 11 nights in chimpanzee nests and on the bare ground to test for differences in sleep quality, potential exposure to disease through bites from possible vectors, and insulation. No difference was found in the total amount of sleep nor in sleep quality; however, sleep was more disturbed on the ground. Differences in sleep disturbance between arboreal and ground conditions seemed primarily due to causes of anxiety and alertness, e.g., vocalizations of terrestrial mammals. Arboreal nest-sleeping seems to reduce risk of bites from possible disease vectors and provide insulation in cold conditions. This preliminary, but direct, test of chimpanzee nest function has implications for the evolutionary transition from limb-roosting to nest-reclining sleep in the hominoids, and from tree-to-ground sleep in the genus Homo. Copyright © 2011 Wiley-Liss, Inc.

Processing multiple non-adjacent dependencies: evidence from sequence learning

PubMed Central

de Vries, Meinou H.; Petersson, Karl Magnus; Geukes, Sebastian; Zwitserlood, Pienie; Christiansen, Morten H.

2012-01-01

Processing non-adjacent dependencies is considered to be one of the hallmarks of human language. Assuming that sequence-learning tasks provide a useful way to tap natural-language-processing mechanisms, we cross-modally combined serial reaction time and artificial-grammar learning paradigms to investigate the processing of multiple nested (A1A2A3B3B2B1) and crossed dependencies (A1A2A3B1B2B3), containing either three or two dependencies. Both reaction times and prediction errors highlighted problems with processing the middle dependency in nested structures (A1A2A3B3_B1), reminiscent of the ‘missing-verb effect’ observed in English and French, but not with crossed structures (A1A2A3B1_B3). Prior linguistic experience did not play a major role: native speakers of German and Dutch—which permit nested and crossed dependencies, respectively—showed a similar pattern of results for sequences with three dependencies. As for sequences with two dependencies, reaction times and prediction errors were similar for both nested and crossed dependencies. The results suggest that constraints on the processing of multiple non-adjacent dependencies are determined by the specific ordering of the non-adjacent dependencies (i.e. nested or crossed), as well as the number of non-adjacent dependencies to be resolved (i.e. two or three). Furthermore, these constraints may not be specific to language but instead derive from limitations on structured sequence learning. PMID:22688641

Can a Red Wood-Ant Nest Be Associated with Fault-Related CH4 Micro-Seepage? A Case Study from Continuous Short-Term In-Situ Sampling

PubMed Central

Grumpe, Arne; Becker, Adrian; Wöhler, Christian

2018-01-01

Simple Summary Methane (CH4) is common on Earth but its natural sources are not well-characterized. We investigated concentrations of CH4 and its stable carbon isotope (δ13C-CH4) within a red wood-ant (RWA; Formica polyctena) nest in the Neuwied Basin, a part of the East Eifel Volcanic Field (EEVF), and tested for associations between methane concentration and RWA activity patterns, earthquakes, and earth tides. Methane degassing was not synchronized with earth tides, nor was it influenced by a micro-earthquake or RWA activity. Elevated CH4 concentrations in nest gas appear to result from a combination of microbial activity and fault-related emissions. The latter could result from micro-seepage of methane derived from low-temperature gas-water-rock reactions that subsequently moves via fault networks through the RWA nest or from overlapping micro-seepage of magmatic CH4 from the Eifel plume. Given the abundance of RWA nests on the landscape, their role as sources of microbial CH4 and biological indicators for abiotically-derived CH4 should be included in estimations of methane emissions that are contributing to climatic change. Abstract We measured methane (CH4) and stable carbon isotope of methane (δ13C-CH4) concentrations in ambient air and within a red wood-ant (RWA; Formica polyctena) nest in the Neuwied Basin (Germany) using high-resolution in-situ sampling to detect microbial, thermogenic, and abiotic fault-related micro-seepage of CH4. Methane degassing from RWA nests was not synchronized with earth tides, nor was it influenced by micro-earthquake degassing or concomitantly measured RWA activity. Two δ13C-CH4 signatures were identified in nest gas: −69‰ and −37‰. The lower peak was attributed to microbial decomposition of organic matter within the RWA nest, in line with previous observations that RWA nests are hot-spots of microbial CH4. The higher peak has not been reported in previous studies. We attribute this peak to fault-related CH4 emissions moving via fault networks into the RWA nest, which could originate either from thermogenic or abiotic CH4 formation. Sources of these micro-seepages could be Devonian schists, iron-bearing “Klerf Schichten”, or overlapping micro-seepage of magmatic CH4 from the Eifel plume. Given the abundance of RWA nests on the landscape, their role as sources of microbial CH4 and biological indicators for abiotically-derived CH4 should be included in estimation of methane emissions that are contributing to climatic change. PMID:29597318

Modeling marbled murrelet (Brachyramphus marmoratus) habitat using LiDAR-derived canopy data

USGS Publications Warehouse

Hagar, Joan C.; Eskelson, Bianca N.I.; Haggerty, Patricia K.; Nelson, S. Kim; Vesely, David G.

2014-01-01

LiDAR (Light Detection And Ranging) is an emerging remote-sensing tool that can provide fine-scale data describing vertical complexity of vegetation relevant to species that are responsive to forest structure. We used LiDAR data to estimate occupancy probability for the federally threatened marbled murrelet (Brachyramphus marmoratus) in the Oregon Coast Range of the United States. Our goal was to address the need identified in the Recovery Plan for a more accurate estimate of the availability of nesting habitat by developing occupancy maps based on refined measures of nest-strand structure. We used murrelet occupancy data collected by the Bureau of Land Management Coos Bay District, and canopy metrics calculated from discrete return airborne LiDAR data, to fit a logistic regression model predicting the probability of occupancy. Our final model for stand-level occupancy included distance to coast, and 5 LiDAR-derived variables describing canopy structure. With an area under the curve value (AUC) of 0.74, this model had acceptable discrimination and fair agreement (Cohen's κ = 0.24), especially considering that all sites in our sample were regarded by managers as potential habitat. The LiDAR model provided better discrimination between occupied and unoccupied sites than did a model using variables derived from Gradient Nearest Neighbor maps that were previously reported as important predictors of murrelet occupancy (AUC = 0.64, κ = 0.12). We also evaluated LiDAR metrics at 11 known murrelet nest sites. Two LiDAR-derived variables accurately discriminated nest sites from random sites (average AUC = 0.91). LiDAR provided a means of quantifying 3-dimensional canopy structure with variables that are ecologically relevant to murrelet nesting habitat, and have not been as accurately quantified by other mensuration methods.

Influence of fine-scale habitat structure on nest-site occupancy, laying date and clutch size in Blue Tits Cyanistes caeruleus

NASA Astrophysics Data System (ADS)

Amininasab, Seyed Mehdi; Vedder, Oscar; Schut, Elske; de Jong, Berber; Magrath, Michael J. L.; Korsten, Peter; Komdeur, Jan

2016-01-01

Most birds have specific habitat requirements for breeding. The vegetation structure surrounding nest-sites is an important component of habitat quality, and can have large effects on avian breeding performance. We studied 13 years of Blue Tit Cyanistes caeruleus population data to determine whether characteristics of vegetation structure predict site occupancy, laying date and number of eggs laid. Measurements of vegetation structure included the density of English Oak Quercus robur, European Beech Fagus sylvatica, and other deciduous, coniferous and non-coniferous evergreen trees, within a 20-m radius of nest-boxes used for breeding. Trees were further sub-divided into specific classes of trunk circumferences to determine the densities for different maturity levels. Based on Principal Component Analysis (PCA), we reduced the total number of 17 measured vegetation variables to 7 main categories, which we used for further analyses. We found that the occupancy rate of sites and the number of eggs laid correlated positively with the proportion of deciduous trees and negatively with the density of coniferous trees. Laying of the first egg was advanced with a greater proportion of deciduous trees. Among deciduous trees, the English Oak appeared to be most important, as a higher density of more mature English Oak trees was associated with more frequent nest-box occupancy, a larger number of eggs laid, and an earlier laying start. Furthermore, laying started earlier and more eggs were laid in nest-boxes with higher occupancy rates. Together, these findings highlight the role of deciduous trees, particularly more mature English Oak, as important predictors of high-quality preferred habitat. These results aid in defining habitat quality and will facilitate future studies on the importance of environmental quality for breeding performance.

On a useful functional representation of control system structure

NASA Technical Reports Server (NTRS)

Malchow, Harvey L.

1988-01-01

An alternative structure for control systems is proposed. The structure is represented by a three-element block diagram and three functional definitions. It is argued that the three functional elements form a canonical set. The set includes the functions description, estimation and control. General overlay of the structure on parallel state and nested-state control systems is discussed. Breakdown of two real nested-state control systems into the proposed functional format is displayed. Application of the process to the mapping of complex control systems R and D efforts is explained with the Mars Rover Sample and Return mission as an example. A previous application of this basic functional structure to Space Station performance requirements organization is discussed.

Polydomy in the ant Ectatomma opaciventre

PubMed Central

Tofolo, Viviane C.; Giannotti, Edilberto; Neves, Erika F.; Andrade, Luis H. C.; M. Lima, Sandro; Súarez, Yzel R.; Antonialli-Junior, William F.

2014-01-01

Abstract Tropical ants commonly exhibit a hyper-dispersed pattern of spatial distribution of nests. In polydomous species, nests may be satellites, that is, secondary structures of the main nest, where the queen is found. In order to evaluate whether the ant Ectatomma opaciventre Roger (Formicidae: Ectatomminae) uses the strategy of building polydomous nests, the spatial distribution pattern of 33 nests in a 1,800 m 2 degraded area located in Rio Claro, SP, Brazil, were investigated using the nearest neighbor method. To complement the results of this investigation, the cuticular chemical profile of eight colonies was analyzed using Fourier transform infrared photoacoustic spectrosco-py (FTIR-PAS). The nests of E. opaciventre presented a hyper-dispersed or regular distribution, which is the most common in ants. The analysis of the cuticular hydrocarbons apparently con-firmed the hypothesis that this species is polydomous, since the chemical profiles of all studied colonies with nests at different sites were very similar to the chemical signature of the single found queen and were also different from those of colonies used as control. PMID:25373168

Phenotypic assessments of peanut nested association mapping (NAM) populations

USDA-ARS?s Scientific Manuscript database

Nested association mapping (NAM) is a valuable innovation and multi-parental mapping population strategy in peanut genetics which increases the power to map quantitative trait loci and assists in extending the gene pool of elite peanut lines. In the peanut research community, two structured mapping ...

Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise

USGS Publications Warehouse

Hatfield, Jeff S.; Reynolds, Michelle H.; Seavy, Nathaniel E.; Krause, Crystal M.

2012-01-01

Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds.

Cortisol treatment affects locomotor activity and swimming behaviour of male smallmouth bass engaged in paternal care: A field study using acceleration biologgers.

PubMed

Algera, Dirk A; Brownscombe, Jacob W; Gilmour, Kathleen M; Lawrence, Michael J; Zolderdo, Aaron J; Cooke, Steven J

2017-11-01

Paternal care, where the male provides sole care for the developing brood, is a common form of reproductive investment among teleost fish and ubiquitous in the Centrarchidae family. Throughout the parental care period, nesting males expend energy in a variety of swimming behaviours, including routine and burst swimming, vigilantly monitoring the nest area and protecting the brood from predators. Parental care is an energetically demanding period, which is presumably made even more difficult if fish are exposed to additional challenges such as those arising from human disturbance, resulting in activation of the hypothalamic-pituitary-interrenal axis (i.e., elevation of cortisol). To study this situation, we examined the effects of experimental manipulation of the stress hormone cortisol on locomotor activity and behaviour of nest guarding male smallmouth bass (Micropterus dolomieu). We exogenously elevated circulating cortisol levels (via intracoelomic implants) and attached tri-axial accelerometers to wild smallmouth bass for three days. During the recovery period (i.e., ≤4h post-release), cortisol-treated fish exhibited significantly reduced locomotor activity and performed significantly less burst and routine swimming relative to control fish, indicating cortisol uptake was rapid, as were the associated behavioural responses. Post-recovery (i.e., >4h post-release), fish with high cortisol exhibited lower locomotor activity and reduced routine swimming relative to controls. Fish were less active and reduced routine and burst swimming at night compared to daylight hours, an effect independent of cortisol treatment. Collectively, our results suggest that cortisol treatment (as a proxy for anthropogenic disturbance and stress) contributed to altered behaviour, and consequently cortisol-treated males decreased parental investment in their brood, which could have potential fitness implications. Copyright © 2017 Elsevier Inc. All rights reserved.

What do giant titanosaur dinosaurs and modern Australasian megapodes have in common?

PubMed Central

Grellet-Tinner, Gerald; Fiorelli, Lucas E.

2015-01-01

Titanosauria is a globally distributed clade of sometimes extremely large Mesozoic herbivorous sauropod dinosaurs. On the basis of current evidence these giant dinosaurs seem to have reproduced in specific and localized nesting sites. However, no investigations have been performed to understand the possible ecological and geological biases that acted for the selection of these nesting sites worldwide. In this study, observations were performed on the best-known Cretaceous nesting sites around the world. Our observations strongly suggest their eggs were incubated with environmental sources of heat, in burial conditions. Taking into account the clutch composition and geometry, the nature and properties of the sediments, the eggshells’ structures and conductance, it would appear that titanosaurs adopted nesting behaviors comparable to the modern Australasian megapodes, using burrow-nesting in diverse media and mound-building strategies. PMID:26623184

Nesting habitat relationships of sympatric Crested Caracaras, Red-tailed Hawks, and White-tailed Hawks in South Texas

USGS Publications Warehouse

Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

2007-01-01

We quantified nesting-site habitats for sympatric White-tailed Hawks (Buteo albicaudatus) (n = 40), Red-tailed Hawks (B. jamaicensis) (n = 39), and Crested Caracaras (Caracara cheriway) (n = 24) in the Coastal Sand Plain of south Texas. White-tailed Hawks and Crested Caracara nest sites occurred in savannas, whereas Red-tailed Hawk nest sites occurred in woodlands on the edge of savannas. White-tailed Hawk nest sites were in shrubs and trees that were shorter (3.5 ?? 1.0 m) and had smaller canopy diameters (5.5 ?? 2.1 m) than those of Red-tailed Hawks (10.1 ?? 2.0 m, 13.7 ?? 5.8 m) and Crested Caracaras (5.6 ?? 1.7 m, 8.5 ?? 3.5 m). Red-tailed Hawk nest sites had higher woody densities (15.7 ?? 9.6 plants) and more woody cover (84 ?? 19%) than those of White-tailed Hawks (5.6 ?? 5.8 plants, 20 ?? 21%) and Crested Caracaras (9.9 ?? 6.7 plants, 55 ?? 34%). Crested Caracara nest sites were in dense, multi-branched shrubs composed of more living material (97 ?? 3%) than those of White-tailed (88 ?? 18%) and Red-tailed hawks (88 ?? 18%). Nest sites of White-tailed Hawks, Red-tailed Hawks, and Crested Caracaras were similar to random samples from the surrounding habitat indicating that preferred nesting habitat was available for each of these species at least within 60 m of active nest sites. Nest tree height, along with woody plant and native grass cover best discriminated nest sites among the three raptor species. There was no overlap at Red-tailed and White-tailed hawk nest sites in vegetation structure, while Crested Caracara nests were in habitat intermediate between the two other species. Partitioning of nesting habitat may be how these raptor species co-exist at the broader landscape scale of our study area in the Coastal Sand Plain of Texas.

Genetic Architecture of Nest Building in Mice LG/J × SM/J

PubMed Central

Sauce, Bruno; de Brito, Reinaldo Alves; Peripato, Andrea Cristina

2012-01-01

Maternal care is critical to offspring growth and survival, which is greatly improved by building an effective nest. Some suggest that genetic variation and underlying genetic effects differ between fitness-related traits and other phenotypes. We investigated the genetic architecture of a fitness-related trait, nest building, in F2 female mice intercrossed from inbred strains SM/J and LG/J using a QTL analysis for six related nest phenotypes (Presence and Structure pre- and postpartum, prepartum Material Used and postpartum Temperature). We found 15 direct-effect QTLs explaining from 4 to 13% of the phenotypic variation in nest building, mostly with non-additive effect. Epistatic analyses revealed 71 significant epistatic interactions which together explain from 28.4 to 75.5% of the variation, indicating an important role for epistasis in the adaptive process of nest building behavior in mice. Our results suggest a genetic architecture with small direct effects and a larger number of epistatic interactions as expected for fitness-related phenotypes. PMID:22654894

ELF communications system ecological monitoring program: Pollinating insect studies

NASA Astrophysics Data System (ADS)

Strickler, Karen; Schriber, J. Mark

1994-11-01

High voltage transmission lines and the earth's and other magnetic fields have been shown to affect honeybee reproduction, survival, orientation, and nest structure. ELY EM fields could have similar effects on native megachilid bees. Two species in the genus Megachile were abundant in artificial nests at experimental and control areas in Dickinson and Iron Counties in Michigan. Data on their nest architecture, nest activity, and emergence/mortality were collected between 1983 and 1993. Eight hypotheses concerning the possible effects of ELY EM fields were considered using these data. The ELY antenna has been fully operational since the summer of 1989. Tests of the hypotheses compare control vs. experimental areas before and after the ELY antenna became fully operational.

Evaluating Great Lakes bald eagle nesting habitat with Bayesian inference

Treesearch

Teryl G. Grubb; William W. Bowerman; Allen J. Bath; John P. Giesy; D. V. Chip Weseloh

2003-01-01

Bayesian inference facilitated structured interpretation of a nonreplicated, experience-based survey of potential nesting habitat for bald eagles (Haliaeetus leucocephalus) along the five Great Lakes shorelines. We developed a pattern recognition (PATREC) model of our aerial search image with six habitat attributes: (a) tree cover, (b) proximity and...

Structural and Practical Identifiability Issues of Immuno-Epidemiological Vector-Host Models with Application to Rift Valley Fever.

PubMed

Tuncer, Necibe; Gulbudak, Hayriye; Cannataro, Vincent L; Martcheva, Maia

2016-09-01

In this article, we discuss the structural and practical identifiability of a nested immuno-epidemiological model of arbovirus diseases, where host-vector transmission rate, host recovery, and disease-induced death rates are governed by the within-host immune system. We incorporate the newest ideas and the most up-to-date features of numerical methods to fit multi-scale models to multi-scale data. For an immunological model, we use Rift Valley Fever Virus (RVFV) time-series data obtained from livestock under laboratory experiments, and for an epidemiological model we incorporate a human compartment to the nested model and use the number of human RVFV cases reported by the CDC during the 2006-2007 Kenya outbreak. We show that the immunological model is not structurally identifiable for the measurements of time-series viremia concentrations in the host. Thus, we study the non-dimensionalized and scaled versions of the immunological model and prove that both are structurally globally identifiable. After fixing estimated parameter values for the immunological model derived from the scaled model, we develop a numerical method to fit observable RVFV epidemiological data to the nested model for the remaining parameter values of the multi-scale system. For the given (CDC) data set, Monte Carlo simulations indicate that only three parameters of the epidemiological model are practically identifiable when the immune model parameters are fixed. Alternatively, we fit the multi-scale data to the multi-scale model simultaneously. Monte Carlo simulations for the simultaneous fitting suggest that the parameters of the immunological model and the parameters of the immuno-epidemiological model are practically identifiable. We suggest that analytic approaches for studying the structural identifiability of nested models are a necessity, so that identifiable parameter combinations can be derived to reparameterize the nested model to obtain an identifiable one. This is a crucial step in developing multi-scale models which explain multi-scale data.

Elevational gradient in clutch size of Red-faced Warblers

USGS Publications Warehouse

Dillon, Kristen G.; Conway, Courtney J.

2015-01-01

Our understanding of life history evolution has benefited from debates regarding the underlying causes, and geographic ubiquity, of spatial patterns in avian clutch sizes. Past studies have revealed that birds lay smaller clutch sizes at higher elevation. However, in most previous studies, investigators have failed to adequately control for elevational differences in breeding phenology. To better understand the elevational gradient in avian clutch size, we need to know how clutch size changes across the entire elevational breeding range of a species (i.e., the shape of the relationship between elevation and clutch size), and whether the elevational gradient in clutch size is merely an artifact of elevational gradients in breeding phenology or breeding season length. We examined the relationship between breeding elevation and clutch size of Red-faced Warblers (Cardellina rubrifrons) along a 1000-m elevational gradient in Arizona. Our objectives were to determine how clutch size changed with elevation, and if the relationship between clutch size and elevation merely reflected elevational changes in breeding season length or phenology. The proportion of 5-egg clutches decreased and the proportion of 3- and 4-egg clutches increased non-linearly with increasing elevation, even after controlling for the elevational gradient in nest initiation date. Thus, average clutch size declined across the elevational breeding range of Red-faced Warblers, but this decline was not due to elevational variation in breeding phenology. Timing of breeding changed, but the duration of the breeding season did not change appreciably across the elevational gradient. Hence, elevational differences in breeding season length or breeding phenology cannot explain why Red-faced Warblers (and perhaps other birds) breeding at higher elevations have smaller clutches.

Observations on distribution, diet, and breeding of the Hawaiian thrush

USGS Publications Warehouse

van Riper, Charles; Scott, J. Michael

1979-01-01

Distribution, breeding habits, and diet of the Hawaiian Thrush were recorded over seven years on the island of Hawaii. The range has been much reduced, with the result that today the species occupies approximately 30% of its former range, no longer being found in the Kohala Mountains or in the Kona area....Data on food preferences indicate the species subsists chiefly on fruits of native trees, when in season, and various insects. Comparison of present feeding habits with observations of earlier workers indicates that the diet has changed. This probably has been a consequence of the loss of suitable habitat at lower elevations....One of the earliest and latest daily singers in Hawaii, the Omao has a repertoire of at least three songs and a number of calls. The species exhibits courtship feeding. Five nests averaged 6.4 m from the ground; nesting materials include small twigs, leaves, grasses mosses, and fern pieces. For the first time the species was found to nest either in cavities or on protected platforms. One or two eggs, each marked with large lavender splotches, compose the clutch. Nestlings have flesh-colored skin, black down, and a bright yellow gape pattern. Time from building of the nest to fledging of the young is about 30 days, and the overall breeding season of the species extends at least from February to October.

Reproductive success of belted kingfishers on the upper Hudson River.

PubMed

Bridge, Eli S; Kelly, Jeffrey F

2013-08-01

Belted kingfishers (Megaceryle alcyon) are predators in many North American aquatic ecosystems; as such, they are prone to bioaccumulation of certain environmental contaminants. In 2002 and 2004, kingfisher eggs collected near the upper Hudson River in New York had elevated concentrations of polychlorinated biphenyls (PCBs), and the kingfisher population in this area was reported to be at risk because of PCB exposure. From 2007 to 2009, the authors monitored 69 kingfisher nests on the Hudson River to track both nest success and survival of individual nestlings. The study site consisted of 2 adjacent sections of the Hudson River, 1 upstream and 1 downstream of a historic PCB source. The authors compared models of nest success that differentially incorporated the following 4 variables that they deemed most likely to affect reproductive output: 1) river section (upstream vs downstream of PCB source), 2) year, 3) hatch date, and 4) abandonment by 1 parent. After ranking models according to Akaike's information criterion for small sample sizes, it was clear that parental abandonment was the most important of the factors examined. River section was not an important parameter, and overall nesting success was slightly higher in the PCB-contaminated section than in the upstream area. These findings support the conclusion that kingfisher productivity is not adversely impacted by PCB contamination in the upper Hudson River. Copyright © 2013 SETAC.

Maternal androgens increase sibling aggression, dominance, and competitive ability in the siblicidal black-legged kittiwake (Rissa tridactyla).

PubMed

Müller, Martina S; Roelofs, Yvonne; Erikstad, Kjell Einar; Groothuis, Ton G G

2012-01-01

Animals and plants routinely produce more offspring than they can afford to rear. Mothers can favour certain young by conferring on them competitive advantages such as a leading position in the birth sequence, more resources or hormones. Avian mothers create hatching asynchrony within a clutch and at the same time bestow the eggs with different concentrations of androgens that may enhance or counteract the competitive advantage experienced by early-hatching "core" young. In siblicidal birds, core young assume a dominant social position in the nest due to their size advantage and when threatened with starvation fatally attack subdominant later-hatching "marginal" young. A role for maternal androgens in siblicidal aggression has frequently been suggested but never tested. We studied this in the facultatively siblicidal black-headed kittiwake. We found that marginal eggs contain higher instead of lower concentrations of androgens than core eggs. Surprisingly, exposure to experimentally elevated yolk androgens increased sibling aggression and dominance, even though in nature marginal eggs never produce dominant chicks. We propose the "adoption facilitation hypothesis" to explain this paradox. This cliff-nesting colonial species has a high adoption rate: ejected marginal kittiwake chicks frequently fall into other nests containing chicks of similar or smaller size and exposure to yolk androgens might help them integrate themselves into a foster nest.

Species-specific differences in the fine structure of learning walk elements in Cataglyphis ants.

PubMed

Fleischmann, Pauline N; Grob, Robin; Wehner, Rüdiger; Rössler, Wolfgang

2017-07-01

Cataglyphis desert ants are famous navigators. Like all central place foragers, they are confronted with the challenge to return home, i.e. relocate an inconspicuous nest entrance in the ground, after their extensive foraging trips. When leaving the underground nest for the first time, desert ants perform a striking behavior, so-called learning walks that are well structured. However, it is still unclear how the ants initially acquire the information needed for sky- and landmark-based navigation, in particular how they calibrate their compass system at the beginning of their foraging careers. Using high-speed video analyses, we show that different Cataglyphis species include different types of characteristic turns in their learning walks. Pirouettes are full or partial rotations (tight turns about the vertical body axis) during which the ants frequently stop and gaze back in the direction of the nest entrance during the longest stopping phases. In contrast, voltes are small walked circles without directed stopping phases. Interestingly, only Cataglyphis ant species living in a cluttered, and therefore visually rich, environment (i.e. C. noda and C. aenescens in southern Greece) perform both voltes and pirouettes. They look back to the nest entrance during pirouettes, most probably to take snapshots of the surroundings. In contrast, C. fortis inhabiting featureless saltpans in Tunisia perform only voltes and do not stop during these turns to gaze back at the nest - even if a set of artificial landmarks surrounds the nest entrance. © 2017. Published by The Company of Biologists Ltd.

Parallel tiled Nussinov RNA folding loop nest generated using both dependence graph transitive closure and loop skewing.

PubMed

Palkowski, Marek; Bielecki, Wlodzimierz

2017-06-02

RNA secondary structure prediction is a compute intensive task that lies at the core of several search algorithms in bioinformatics. Fortunately, the RNA folding approaches, such as the Nussinov base pair maximization, involve mathematical operations over affine control loops whose iteration space can be represented by the polyhedral model. Polyhedral compilation techniques have proven to be a powerful tool for optimization of dense array codes. However, classical affine loop nest transformations used with these techniques do not optimize effectively codes of dynamic programming of RNA structure predictions. The purpose of this paper is to present a novel approach allowing for generation of a parallel tiled Nussinov RNA loop nest exposing significantly higher performance than that of known related code. This effect is achieved due to improving code locality and calculation parallelization. In order to improve code locality, we apply our previously published technique of automatic loop nest tiling to all the three loops of the Nussinov loop nest. This approach first forms original rectangular 3D tiles and then corrects them to establish their validity by means of applying the transitive closure of a dependence graph. To produce parallel code, we apply the loop skewing technique to a tiled Nussinov loop nest. The technique is implemented as a part of the publicly available polyhedral source-to-source TRACO compiler. Generated code was run on modern Intel multi-core processors and coprocessors. We present the speed-up factor of generated Nussinov RNA parallel code and demonstrate that it is considerably faster than related codes in which only the two outer loops of the Nussinov loop nest are tiled.

Wired: impacts of increasing power line use by a growing bird population

NASA Astrophysics Data System (ADS)

Moreira, Francisco; Encarnação, Vitor; Rosa, Gonçalo; Gilbert, Nathalie; Infante, Samuel; Costa, Julieta; D'Amico, Marcello; Martins, Ricardo C.; Catry, Inês

2017-02-01

Power lines are increasingly widespread across many regions of the planet. Although these linear infrastructures are known for their negative impacts on bird populations, through collision and electrocution, some species take advantage of electricity pylons for nesting. In this case, estimation of the net impact of these infrastructures at the population level requires an assessment of trade-offs between positive and negative impacts. We compiled historical information (1958-2014) of the Portuguese white stork Ciconia ciconia population to analyze long-term changes in numbers, distribution range and use of nesting structures. White stork population size increased 660% up to 12000 breeding pairs between 1984 and 2014. In the same period, the proportion of nests on electricity pylons increased from 1% to 25%, likely facilitated by the 60% increase in the length of the very high tension power line grid (holding the majority of the nests) in the stork’s distribution range. No differences in breeding success were registered for storks nesting on electricity pylons versus other structures, but a high risk of mortality by collision and electrocution with power lines was estimated. We discuss the implications of this behavioral change, and of the management responses by power line companies, both for stork populations and for managers.

Lack of spatial genetic structure among nesting and wintering King Eiders

USGS Publications Warehouse

Pearce, J.M.; Talbot, S.L.; Pierson, Barbara J.; Petersen, M.R.; Scribner, K.T.; Dickson, D.L.; Mosbech, A.

2004-01-01

The King Eider (Somateria spectabilis) has been delineated into two broadly distributed breeding populations in North America (the western and eastern Arctic) on the basis of banding data and their use of widely separated Pacific and Atlantic wintering areas. Little is known about the level of gene flow between these two populations. Also unknown is whether behavioral patterns common among migratory waterfowl, such as site fidelity to wintering areas and pair formation at these sites, have existed for sufficient time to create a population structure defined by philopatry to wintering rather than to nesting locations. We used six nuclear microsatellite DNA loci and cytochrome b mitochondrial DNA sequence data to estimate the extent of spatial genetic differentiation among nesting and wintering areas of King Eiders across North America and adjacent regions. Estimates of interpopulation variance in microsatellite allele and mtDNA haplotype frequency were both low and nonsignificant based on samples from three wintering and four nesting areas. Results from nested clade analysis, mismatch distributions, and coalescent-based analyses suggest historical population growth and gene flow that collectively may have homogenized gene frequencies. The presence of several unique mtDNA haplotypes among birds wintering near Greenland suggests that gene flow may now be more limited between the western and eastern Arctic, which is consistent with banding data.

Influences of Species Interactions With Aggressive Ants and Habitat Filtering on Nest Colonization and Community Composition of Arboreal Twig-Nesting Ants.

PubMed

Philpott, Stacy M; Serber, Zachary; De la Mora, Aldo

2018-04-05

Ant community assembly is driven by many factors including species interactions (e.g., competition, predation, parasitism), habitat filtering (e.g., vegetation differences, microclimate, food and nesting resources), and dispersal. Canopy ant communities, including dominant and twig-nesting ants, are structured by all these different factors, but we know less about the impacts of species interactions and habitat filters acting at the colonization or recruitment stage. We examined occupation of artificial twig nests placed in shade trees in coffee agroecosystems. We asked whether species interactions-aggression from the dominant canopy ant, Azteca sericeasur Longino (Hymenoptera: Formicidae)-or habitat filtering-species of tree where nests were placed or surrounding vegetation-influence colonization, species richness, and community composition of twig-nesting ants. We found 20 species of ants occupying artificial nests. Nest occupation was lower on trees with A. sericeasur, but did not differ depending on tree species or surrounding vegetation. Yet, there were species-specific differences in occupation depending on A. sericeasur presence and tree species. Ant species richness did not vary with A. sericeasur presence or tree species. Community composition varied with A. sericeasur presence and surrounding vegetation. Our results suggest that species interactions with dominant ants are important determinants of colonization and community composition of twig-nesting ants. Habitat filtering at the level of tree species did not have strong effects on twig-nesting ants, but changes in coffee management may contribute to differences in community composition with important implications for ant conservation in agricultural landscapes, as well as biological control of coffee pests.

Genetic Relatedness of Low Solitary Nests of Apis dorsata from Marang, Terengganu, Malaysia

PubMed Central

Ali, Abdul Manaf; Tan, Soon Guan; Adam, Nur Azura; Lau, Wei Hong

2012-01-01

Knowledge on the population of genetic structure and ecological behaviour of Apis dorsata from Peninsular Malaysia is needed for effective management and conservation of this species since unsustainable whole solitary low nest cutting for product harvesting is the current common practice here. The analysis of 15 single locus DNA microsatellite markers on samples from 20 solitary nests of A. dorsata showed that while these markers were polymorphic, high intracolonial relatedness existed. Furthermore, in general, slightly negative values of intercolony relatedness (R) among the nests of A. dorsata were found. However, positive values of mean intercolony relatedness were observed between 54 pairs of nests out of 190 possible combinations. The R values among nest pairs 3–4 and 3–5 was higher than 0.50 showing that their queens were half siblings, whereas nest pair 19–20 showed relatedness of 0.95 indicating that the same queen was sampled. The results that we obtained could not conclusively support the hypothesis of this study that the honey hunters in Marang district of Malaysia repeatedly harvest the same nest located at a different site and at a different time during the same honey harvesting season. However, our finding of an appreciable level of intercolonial relatedness between several pairs of nests in this pioneer study indicated that a comprehensive study with a larger sample size of solitary nests found throughout the region would be necessary to provide concrete proof for this novel idea. PMID:22911733

Local individual preferences for nest materials in a passerine bird.

PubMed

Mennerat, Adèle; Perret, Philippe; Lambrechts, Marcel M

2009-01-01

Variation in the behavioural repertoire of animals is acquired by learning in a range of animal species. In nest-building birds, the assemblage of nest materials in an appropriate structure is often typical of a bird genus or species. Yet plasticity in the selection of nest materials may be beneficial because the nature and abundance of nest materials vary across habitats. Such plasticity can be learned, either individually or socially. In Corsican populations of blue tits Cyanistes caeruleus, females regularly add in their nests fragments of several species of aromatic plants during the whole breeding period. The selected plants represent a small fraction of the species present in the environment and have positive effects on nestlings. We investigated spatiotemporal variations of this behaviour to test whether the aromatic plant species composition in nests depends on 1) plant availability in territories, 2) female experience or 3) female identity. Our results indicate that territory plays a very marginal role in the aromatic plant species composition of nests. Female experience is not related to a change in nest plant composition. Actually, this composition clearly depends on female identity, i.e. results from individual preferences which, furthermore, are repeatable both within and across years. A puzzling fact is the strong difference in plant species composition of nests across distinct study plots. This study demonstrates that plant species composition of nests results from individual preferences that are homogeneous within study plots. We propose several hypotheses to interpret this pattern of spatial variation before discussing them in the light of preliminary results. As a conclusion, we cannot exclude the possibility of social transmission of individual preferences for aromatic plants. This is an exciting perspective for further work in birds, where nest construction behaviour has classically been considered as a stereotypic behaviour.

Cost-efficient designs for three-arm trials with treatment delivered by health professionals: Sample sizes for a combination of nested and crossed designs

PubMed Central

Moerbeek, Mirjam

2018-01-01

Background This article studies the design of trials that compare three treatment conditions that are delivered by two types of health professionals. The one type of health professional delivers one treatment, and the other type delivers two treatments, hence, this design is a combination of a nested and crossed design. As each health professional treats multiple patients, the data have a nested structure. This nested structure has thus far been ignored in the design of such trials, which may result in an underestimate of the required sample size. In the design stage, the sample sizes should be determined such that a desired power is achieved for each of the three pairwise comparisons, while keeping costs or sample size at a minimum. Methods The statistical model that relates outcome to treatment condition and explicitly takes the nested data structure into account is presented. Mathematical expressions that relate sample size to power are derived for each of the three pairwise comparisons on the basis of this model. The cost-efficient design achieves sufficient power for each pairwise comparison at lowest costs. Alternatively, one may minimize the total number of patients. The sample sizes are found numerically and an Internet application is available for this purpose. The design is also compared to a nested design in which each health professional delivers just one treatment. Results Mathematical expressions show that this design is more efficient than the nested design. For each pairwise comparison, power increases with the number of health professionals and the number of patients per health professional. The methodology of finding a cost-efficient design is illustrated using a trial that compares treatments for social phobia. The optimal sample sizes reflect the costs for training and supervising psychologists and psychiatrists, and the patient-level costs in the three treatment conditions. Conclusion This article provides the methodology for designing trials that compare three treatment conditions while taking the nesting of patients within health professionals into account. As such, it helps to avoid underpowered trials. To use the methodology, a priori estimates of the total outcome variances and intraclass correlation coefficients must be obtained from experts’ opinions or findings in the literature. PMID:29316807

Landscape heterogeneity drives intra-population niche variation and reproduction in an arctic top predator

PubMed Central

L'Hérault, Vincent; Franke, Alastair; Lecomte, Nicolas; Alogut, Adam; Bêty, Joël

2013-01-01

While intra-population variability in resource use is ubiquitous, little is known of how this measure of niche diversity varies in space and its role in population dynamics. Here we examined how heterogeneous breeding environments can structure intra-population niche variation in both resource use and reproductive output. We investigated intra-population niche variation in the Arctic tundra ecosystem, studying peregrine falcon (Falco peregrinus tundrius, White) breeding within a terrestrial-marine gradient near Rankin Inlet, Nunavut, Canada. Using stable isotope analysis, we found that intra-population niches varied at the individual level; we examined within-nest and among-nest variation, though only the latter varied along the terrestrial-marine gradient (i.e., increased among-nest variability among birds nesting within the marine environment, indicating higher degree of specialization). Terrestrial prey species (small herbivores and insectivores) were consumed by virtually all falcons. Falcons nesting within the marine environment made use of marine prey (sea birds), but depended heavily on terrestrial prey (up to 90% of the diet). Using 28-years of peregrine falcon nesting data, we found a positive relationship between the proportion of terrestrial habitat surrounding nest sites and annual nestling production, but no relationship with the likelihood of successfully rearing at least one nestling reaching 25 days old. Annually, successful inland breeders raised 0.47 more young on average compared to offshore breeders, which yields potential fitness consequences for this long-living species. The analyses of niche and reproductive success suggest a potential breeding cost for accessing distant terrestrial prey, perhaps due to additional traveling costs, for those individuals with marine nest site locations. Our study indicates how landscape heterogeneity can generate proximate (niche variation) and ultimate (reproduction) consequences on a population of generalist predator. We also show that within-individual and among-individual variation are not mutually exclusive, but can simultaneously arise and structure intra-population niche variation. PMID:24101979

Resource Quantity and Quality Determine the Inter-Specific Associations between Ecosystem Engineers and Resource Users in a Cavity-Nest Web

PubMed Central

Robles, Hugo; Martin, Kathy

2013-01-01

While ecosystem engineering is a widespread structural force of ecological communities, the mechanisms underlying the inter-specific associations between ecosystem engineers and resource users are poorly understood. A proper knowledge of these mechanisms is, however, essential to understand how communities are structured. Previous studies suggest that increasing the quantity of resources provided by ecosystem engineers enhances populations of resource users. In a long-term study (1995-2011), we show that the quality of the resources (i.e. tree cavities) provided by ecosystem engineers is also a key feature that explains the inter-specific associations in a tree cavity-nest web. Red-naped sapsuckers ( Sphyrapicus nuchalis ) provided the most abundant cavities (52% of cavities, 0.49 cavities/ha). These cavities were less likely to be used than other cavity types by mountain bluebirds ( Sialia currucoides ), but provided numerous nest-sites (41% of nesting cavities) to tree swallows ( Tachycineta bicolour ). Swallows experienced low reproductive outputs in northern flicker ( Colaptes auratus ) cavities compared to those in sapsucker cavities (1.1 vs. 2.1 fledglings/nest), but the highly abundant flickers (33% of cavities, 0.25 cavities/ha) provided numerous suitable nest-sites for bluebirds (58%). The relative shortage of cavities supplied by hairy woodpeckers ( Picoides villosus ) and fungal/insect decay (<10% of cavities each, <0.09 cavities/ha) provided fewer breeding opportunities (<15% of nests), but represented high quality nest-sites for both bluebirds and swallows. Because both the quantity and quality of resources supplied by different ecosystem engineers may explain the amount of resources used by each resource user, conservation strategies may require different management actions to be implemented for the key ecosystem engineer of each resource user. We, therefore, urge the incorporation of both resource quantity and quality into models that assess community dynamics to improve conservation actions and our understanding of ecological communities based on ecosystem engineering. PMID:24040324

Resource quantity and quality determine the inter-specific associations between ecosystem engineers and resource users in a cavity-nest web.

PubMed

Robles, Hugo; Martin, Kathy

2013-01-01

While ecosystem engineering is a widespread structural force of ecological communities, the mechanisms underlying the inter-specific associations between ecosystem engineers and resource users are poorly understood. A proper knowledge of these mechanisms is, however, essential to understand how communities are structured. Previous studies suggest that increasing the quantity of resources provided by ecosystem engineers enhances populations of resource users. In a long-term study (1995-2011), we show that the quality of the resources (i.e. tree cavities) provided by ecosystem engineers is also a key feature that explains the inter-specific associations in a tree cavity-nest web. Red-naped sapsuckers (Sphyrapicusnuchalis) provided the most abundant cavities (52% of cavities, 0.49 cavities/ha). These cavities were less likely to be used than other cavity types by mountain bluebirds (Sialiacurrucoides), but provided numerous nest-sites (41% of nesting cavities) to tree swallows (Tachycinetabicolour). Swallows experienced low reproductive outputs in northern flicker (Colaptesauratus) cavities compared to those in sapsucker cavities (1.1 vs. 2.1 fledglings/nest), but the highly abundant flickers (33% of cavities, 0.25 cavities/ha) provided numerous suitable nest-sites for bluebirds (58%). The relative shortage of cavities supplied by hairy woodpeckers (Picoidesvillosus) and fungal/insect decay (<10% of cavities each, <0.09 cavities/ha) provided fewer breeding opportunities (<15% of nests), but represented high quality nest-sites for both bluebirds and swallows. Because both the quantity and quality of resources supplied by different ecosystem engineers may explain the amount of resources used by each resource user, conservation strategies may require different management actions to be implemented for the key ecosystem engineer of each resource user. We, therefore, urge the incorporation of both resource quantity and quality into models that assess community dynamics to improve conservation actions and our understanding of ecological communities based on ecosystem engineering.

Successful nesting by a Bald Eagle pair in prairie grasslands of the Texas Panhandle

USGS Publications Warehouse

Boal, G.W.; Giovanni, M.D.; Beall, B.N.

2006-01-01

We observed a breeding Bald Eagle (Haliaeetus leitcocephalus) pair nesting in a short-grass prairie and agricultural community on the southern Great Plains of the Texas Panhandle in 2004 and 2005. The nesting eagles produced 1 fledgling in 2004 and 2 fledglings in 2005. Our assessment of landcover types within a 5-km radius of the nest indicated that grasslands accounted for most of the area (90%), followed by agricultural lands (8%). Black-tailed prairie dog (Cynomys ludovicianus) colonies occupied 2.5% of the area, and single human residences with associated structures (i.e., barns) occupied 2.5 ha in surface area was 51 km from the nest. An analysis of regurgitated castings collected near the nest revealed a mammalian-dominated, breeding-season diet with black-tailed prairie dogs occurring in 80.9% of the castings. Other identified prey included cottontails (Sylvilagus spp., 15.9%), black-tailed jackrabbits (Lepus californicus, 3.2%), pronghorn (Antilocapra americana, 3.2%), and plains pocket gopher (Geomys bursarius, 1.6%). Bird remains were also present in 34.9% of the castings. This is the first reported successful nesting of Bald Eagles in the panhandle region of Texas since 1916; the nest is particularly unique because of its distance from any substantial body of water.

A meta-analysis of lesser prairie-chicken nesting and brood-rearing habitats: implications for habitat management

USGS Publications Warehouse

Hagen, Christian A.; Grisham, Blake A.; Boal, Clint W.; Haukos, David A.

2013-01-01

The distribution and range of lesser prairie-chicken (Tympanuchus pallidicinctus) has been reduced by >90% since European settlement of the Great Plains of North America. Currently, lesser prairie-chickens occupy 3 general vegetation communities: sand sagebrush (Artemisia filifolia), sand shinnery oak (Quercus havardii), and mixed-grass prairies juxtaposed with Conservation Reserve Program grasslands. As a candidate for protection under the Endangered Species Act, there is a need for a synthesis that characterizes habitat structure rangewide. Thus, we conducted a meta-analysis of vegetation characteristics at nest sites and brood habitats to determine whether there was an overall effect (Hedges' d) of habitat selection and to estimate average (95% CI) habitat characteristics at use sites. We estimated effect sizes (di) from the difference between use (nests and brood sites) and random sampling sites for each study (n = 14), and derived an overall effect size (d++). There was a general effect for habitat selection as evidenced by low levels of variation in effect sizes across studies and regions. There was a small to medium effect (d++) = 0.20-0.82) of selection for greater vertical structure (visual obstruction) by nesting females in both vegetation communities, and selection against bare ground (d++ = 0.20-0.58). Females with broods exhibited less selectivity for habitat components except for vertical structure. The variation of d++ was greater during nesting than brooding periods, signifying a seasonal shift in habitat use, and perhaps a greater range of tolerance for brood-rearing habitat. The overall estimates of vegetation cover were consistent with those provided in management guidelines for the species.

Spectrum of lesions derived from branchial arches occurring in the thyroid: from solid cell nests to tumors.

PubMed

Srbecka, Kristyna; Michalova, Kvetoslava; Curcikova, Radmila; Michal, Michael; Dubova, Magdalena; Svajdler, Marian; Michal, Michal; Daum, Ondrej

2017-09-01

There is a group of lesions in the head and neck region derived from branchial arches and related structures which, when inflamed, are characterized by the formation of cysts lined by squamous or glandular epithelium and surrounded by a heavy inflammatory infiltrate rich in germinal centers. In the thyroid, the main source of various structures which may cause diagnostic dilemma is the ultimobranchial body. To investigate the spectrum of such thyroid lesions, the consultation files were reviewed for thyroid samples containing pathological structures regarded to arise from the ultimobranchial body. Positive reaction with antibodies against CK5/6, p63, galectin 3, and CEA, and negative reaction with antibodies against thyroglobulin, TTF-1, and calcitonin were used to confirm the diagnosis. The specific subtype of the ultimobranchial body-derived lesion was then determined based on histological examination of H&E-stained slides. Twenty-one cases of ultimobranchial body-derived lesions were retrieved from the consultation files, 20 of them along with clinical information (M/F = 6/14, mean age 55 years, range 36-68 years). Lesions derived from the ultimobranchial body were classified as follows: (hyperplastic) solid cell nests (nine cases), solid cell nests with focal cystic change (five cases), cystic solid cell nests (two cases), branchial cleft-like cyst (four cases), and finally a peculiar Warthin tumor-like lesion (one case). We suggest that the common denominator of these structures is that they all arise due to activation of inflammatory cells around the vestigial structures, which leads to cystic dilatation and proliferation of the epithelial component.

Population structuring of the ubiquitous stingless bee Tetragonisca angustula in southern Brazil as revealed by microsatellite and mitochondrial markers.

PubMed

Francisco, Flávio O; Santiago, Leandro R; Mizusawa, Yuri M; Oldroyd, Benjamin P; Arias, Maria C

2017-10-01

Tetragonisca angustula is one of the most widespread stingless bees in the Neotropics. This species swarms frequently and is extremely successful in urban environments. In addition, it is one of the most popular stingless bee species for beekeeping in Latin America, so nest transportation and trading is common. Nest transportation can change the genetic structure of the host population, reducing inbreeding and increasing homogenization. Here, we evaluate the genetic structure of 17 geographic populations of T. angustula in southern Brazil to quantify the level of genetic differentiation between populations. Analyses were conducted on partially sequenced mitochondrial genes and 11 microsatellite loci of 1002 workers from 457 sites distributed on the mainland and on 3 islands. Our results show that T. angustula populations are highly differentiated as demonstrated by mitochondrial DNA (mtDNA) and microsatellite markers. Of 73 haplotypes, 67 were population-specific. MtDNA diversity was low in 9 populations but microsatellite diversity was moderate to high in all populations. Microsatellite data suggest 10 genetic clusters and low level of gene flow throughout the studied area. However, physical barriers, such as rivers and mountain ranges, or the presence or absence of forest appear to be unrelated to population clusters. Factors such as low dispersal, different ecological conditions, and isolation by distance are most likely shaping the population structure of this species. Thus far, nest transportation has not influenced the general population structure in the studied area. However, due to the genetic structure we found, we recommend that nest transportation should only occur within and between populations that are genetically similar. © 2016 Institute of Zoology, Chinese Academy of Sciences.

A hierarchical nest survival model integrating incomplete temporally varying covariates

PubMed Central

Converse, Sarah J; Royle, J Andrew; Adler, Peter H; Urbanek, Richard P; Barzen, Jeb A

2013-01-01

Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the biting-insect hypothesis and other hypotheses for nesting failure in this reintroduced population; resulting inferences will support ongoing efforts to manage this population via an adaptive management approach. Wider application of our approach offers promise for modeling the effects of other temporally varying, but imperfectly observed covariates on nest survival, including the possibility of modeling temporally varying covariates collected from incubating adults. PMID:24340185

A hierarchical nest survival model integrating incomplete temporally varying covariates

USGS Publications Warehouse

Converse, Sarah J.; Royle, J. Andrew; Adler, Peter H.; Urbanek, Richard P.; Barzan, Jeb A.

2013-01-01

Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the biting-insect hypothesis and other hypotheses for nesting failure in this reintroduced population; resulting inferences will support ongoing efforts to manage this population via an adaptive management approach. Wider application of our approach offers promise for modeling the effects of other temporally varying, but imperfectly observed covariates on nest survival, including the possibility of modeling temporally varying covariates collected from incubating adults.

Inflatable nested toroid structure

NASA Technical Reports Server (NTRS)

Johnson, Christopher J. (Inventor); Raboin, Jasen L. (Inventor); Spexarth, Gary R. (Inventor)

2011-01-01

An inflatable structure comprises at least two generally toroidal, inflatable modules. When in a deployed mode, the first, inner module has a major diameter less than that of a second, outer module and is positioned within the inner circumference of the outer module such that the first module is nested circumferentially alongside the second module. The inflatable structure, in a non-deployed, non-inflated mode, is of compact configuration and adapted to be transported to a site of deployment. When deployed, the inflatable structure is of substantially increased interior volume. In one embodiment, access between the interior of the first module and the second module is provided by at least one port or structural pass-through. In another embodiment, the inflatable structure includes at least one additional generally toroidal module external of and circumferentially surrounding the second module.

A new biodegradable sisal fiber-starch packing composite with nest structure.

PubMed

Xie, Qi; Li, Fangyi; Li, Jianfeng; Wang, Liming; Li, Yanle; Zhang, Chuanwei; Xu, Jie; Chen, Shuai

2018-06-01

A new completely biodegradable sisal fiber-starch packing composite was proposed. The effects of fiber content and alkaline treatment on the cushioning property of the composites were studied from energy absorption efficiency, cellular microstructure and compatibility between fiber and starch. With increasing fiber content, the nest structure of composites becomes dense first and then loosens, resulting in initial enhancement and subsequent weakening of the cushioning property of the composites. The composite with 4:13 mass ratio of fiber and thermoplastic starch (TPS) exhibit the optimal cushioning property. Alkaline treatment increases the compatibility between sisal fiber and TPS, promotes the formation of dense nest structure, thereby enhances the cushioning property of the composites. After biodegradability tests for 28 days, the weight loss of the composites was 62.36%. It's found that the composites are a promising replacement for expandable polystyrene (EPS) as packing material, especially under large compression load (0.7-6 MPa). Copyright © 2018 Elsevier Ltd. All rights reserved.

Field guide to red tree vole nests

Treesearch

Damon B. Lesmeister; James K. Swingle

2017-01-01

Surveys for red tree vole (Arborimus longicaudus) nests require tree climbing because the species is a highly specialized arboreal rodent that live in the tree canopy of coniferous forests in western Oregon and northwestern California. Tree voles are associated with old coniferous forest (≥80 years old) that are structurally complex, but are often...

Application of a Multidimensional Nested Logit Model to Multiple-Choice Test Items

ERIC Educational Resources Information Center

Bolt, Daniel M.; Wollack, James A.; Suh, Youngsuk

2012-01-01

Nested logit models have been presented as an alternative to multinomial logistic models for multiple-choice test items (Suh and Bolt in "Psychometrika" 75:454-473, 2010) and possess a mathematical structure that naturally lends itself to evaluating the incremental information provided by attending to distractor selection in scoring. One potential…

Epipona media cooper (Hymenoptera: Vespidae), a social wasp new to the Brazilian Atlantic Forest.

PubMed

Menezes, Rodolpho S T; Carvalho Filho, Antonio F; Raw, Anthony; Costa, Marco A

2010-01-01

An occupied nest of Epipona media Cooper was discovered and collected in a cabruca (cocoa plantation with native tree cover). This is the first record of E. media from Bahia State. We described the nest structure and compared the adults with the closely related species Epipona tatua Cuvier.

Contents and Structure Atta texana Nest in Summer

Treesearch

John C. Moser

1963-01-01

A large nest of Atta texana (Buckley) in central Louisiana was partially excavated in August 1960. Twelve dormancy, 5 detritus, and 93 fungus-garden cavities were found. Fungus-garden cavities near the surface outnumbered those at lower depths and contained most of the fungus material and brood. Inquilines were most numerous in detritus cavities....

Phylogeography of colonially nesting seabirds, with special reference to global matrilineal patterns in the sooty tern (Sterna fuscata).

PubMed

Avise, J C; Nelson, W S; Bowen, B W; Walker, D

2000-11-01

Sooty tern (Sterna fuscata) rookeries are scattered throughout the tropical oceans. When not nesting, individuals wander great distances across open seas, but, like many other seabirds, they tend to be site-faithful to nesting locales in successive years. Here we examine the matrilineal history of sooty terns on a global scale. Assayed colonies within an ocean are poorly differentiated in mitochondrial DNA sequence, a result indicating tight historical ties. However, a shallow genealogical partition distinguishes Atlantic from Indo-Pacific rookeries. Phylogeographic patterns in the sooty tern are compared to those in other colonially nesting seabirds, as well as in the green turtle (Chelonia mydas), an analogue of tropical seabirds in some salient aspects of natural history. Phylogeographic structure within an ocean is normally weak in seabirds, unlike the pronounced matrilineal structure in green turtles. However, the phylogeographic partition between Atlantic and Indo-Pacific rookeries in sooty terns mirrors, albeit in shallower evolutionary time, the major matrilineal subdivision in green turtles. Thus, global geology has apparently influenced historical gene movements in these two circumtropical species.

Facile synthesis of bird's nest-like TiO2 microstructure with exposed (001) facets for photocatalytic degradation of methylene blue

NASA Astrophysics Data System (ADS)

Zhang, Guozhong; Zhang, Shuqu; Wang, Longlu; Liu, Ran; Zeng, Yunxiong; Xia, Xinnian; Liu, Yutang; Luo, Shenglian

2017-01-01

The scrupulous design of hierarchical structure and highly active crystal facets exposure is essential for the creation of photocatalytic system. However, it is still a big challenge for scrupulous design of TiO2 architectures. In this paper, bird's nest-like anatase TiO2 microstructure with exposed highly active (001) surface has been successfully synthesized by a facile one-step solvothermal method. Methylene blue (MB) is chosen as a model pollutant to evaluate photocatalytic activity of as-obtained TiO2 samples. The results show that the photocatalytic activity of the bird's nest-like sample is more excellent than P25 in the degradation of MB due to high specific surface area and highly active (001) crystal facets exposure when tested under simulated solar light. Besides, it can be readily separated from the photocatalytic system by sedimentation after photocatalytic reaction, which is a significant advantage against conventional powder photocatalyst. The bird's nest-like microspheres with novel structure may have potential application in photocatalysis and other fields.

Genetic variability in captive populations of the stingless bee Tetragonisca angustula.

PubMed

Santiago, Leandro R; Francisco, Flávio O; Jaffé, Rodolfo; Arias, Maria C

2016-08-01

Low genetic variability has normally been considered a consequence of animal husbandry and a major contributing factor to declining bee populations. Here, we performed a molecular analysis of captive and wild populations of the stingless bee Tetragonisca angustula, one of the most commonly kept species across South America. Microsatellite analyses showed similar genetic variability between wild and captive populations However, captive populations showed lower mitochondrial genetic variability. Male-mediated gene flow, transport and division of nests are suggested as the most probable explanations for the observed patterns of genetic structure. We conclude that increasing the number of colonies kept through nest divisions does not negatively affect nuclear genetic variability, which seems to be maintained by small-scale male dispersal and human-mediated nest transport. However, the transport of nests from distant localities should be practiced with caution given the high genetic differentiation observed between samples from western and eastern areas. The high genetic structure verified is the result of a long-term evolutionary process, and bees from distant localities may represent unique evolutionary lineages.

Habitat selection and management of the Hawaiian crow

USGS Publications Warehouse

Giffen, J.G.; Scott, J.M.; Mountainspring, S.

1987-01-01

The abundance and range of the Hawaiian crow, or alala, (Corvus hawaiiensis) have decreased drastically since the 1890's. Fewer than 10 breeding pairs remained in the wild in 1985. A sample of 82 nests during 1970-82 were used to determine habitat associations. Two hundred firty-nine alala observations were used to estimate densities occurring in different vegetation types in 1978. Compared to available habitat, more nests and higher bird densities during the breeding season occurred in areas where: (1) canopy cover was > 60%; (2) koa (Acacia koa) and ohia (Metrosideros polymorpha) were dominant species in the crown layer; (3) native plants constituted > 75% of the understory cover; and (4) the elevation was 1,100-1,500 m. Compared to breeding habitat, nonbreeding habitat tended to lie at lower elevations and in wetter forests having the crown layer dominated by ohia but lacking koa. Habitat loss is a major factor underlying the decline of this species although predation on fledgings, avian disease, and shooting also have reduced the population. Remaining key habitat areas have little or no legal protection through zoning and land ownership. Preserves should be established to encompass the location of existing pairs and to assure the provision of optimum breeding habitat and suitable nonbreeding habitat.

Factors affecting breeding dispersal of European ducks on Engure Marsh, Latvia

USGS Publications Warehouse

Blums, P.; Nichols, J.D.; Lindberg, M.S.; Hines, J.E.; Mednis, A.

2003-01-01

1. We used up to 35 years of capture-recapture data from nearly 3300 individual female ducks nesting on Engure Marsh, Latvia, and multistate modelling to test predictions about the influence of environmental, habitat and management factors on breeding dispersal probability within the marsh. 2. Analyses based on observed dispersal distances of common pochards and tufted ducks provided no evidence that breeding success in year t influenced dispersal distance between t and t + 1. 3. Breeding dispersal distances (year t to t + 1) of pochards and tufted ducks were associated with a delay in relative nest initiation dates in year t + 1. The delay was greater for pochards (c. 4 days) than for tufted ducks (c. 2 days) when females dispersed > 0.8 km. 4. Northern shovelers and tufted ducks moved from a large island to small islands at low water levels and from small islands to the large island at high water levels before the construction of elevated small islands (1960-82). Following this habitat management (1983-94). breeding fidelity was extremely high and not influenced by water level in the marsh for either species. 5. Because pochard nesting habitats in black-headed gull colonies were saturated during the entire study period, nesting females moved into and out of colonies with similar probabilities. Local survival probabilities and incubation body masses were higher for both yearlings (SY) and adults (ASY) nesting within gull colonies, suggesting that these females were of better quality than females nesting outside of the colonies. 6. Tufted ducks showed higher probabilities of moving from islands to emergent marshes when water levels were higher both before and after habitat management. However, rates of movement for a given water level were higher during the period before management than after. 7. Both pochards and tufted ducks exhibited asymmetric movement with respect to proximity to water, with higher movement probabilities to near-water nesting locations than away from these locations. 8. Multistate capture-recapture models provided analyses that were useful in investigating sources of variation in breeding dispersal probabilities.

Fecal sacs attract insects to the nest and provoke an activation of the immune system of nestlings.

PubMed

Ibáñez-Álamo, Juan Diego; Ruiz-Raya, Francisco; Rodríguez, Laura; Soler, Manuel

2016-01-01

Nest sanitation is a widespread but rarely studied behavior in birds. The most common form of nest sanitation behavior, the removal of nestling feces, has focused the discussion about which selective pressures determine this behavior. The parasitism hypothesis, which states that nestling fecal sacs attract parasites that negatively affect breeding birds, was proposed 40 years ago and is frequently cited as a demonstrated fact. But, to our knowledge, there is no previous experimental test of this hypothesis. We carried out three different experiments to investigate the parasitism hypothesis. First, we used commercial McPhail traps to test for the potential attraction effect of nestling feces alone on flying insects. We found that traps with fecal sacs attracted significantly more flies (Order Diptera), but not ectoparasites, than the two control situations. Second, we used artificial blackbird (Turdus merula) nests to investigate the combined attraction effect of feces and nest materials on arthropods (not only flying insects). Flies, again, were the only group of arthropods significantly attracted by fecal sacs. We did not detect an effect on ectoparasites. Third, we used active blackbird nests to investigate the potential effect of nestling feces in ecto- and endoparasite loads in real nestlings. The presence of fecal sacs near blackbird nestlings did not increase the number of louse flies or chewing lice, and unexpectedly reduced the number of nests infested with mites. The endoparasite prevalence was also not affected. In contrast, feces provoked an activation of the immune system as the H/L ratio of nestlings living near excrements was significantly higher than those kept under the two control treatments. Surprisingly, our findings do not support the parasitism hypothesis, which suggests that parasites are not the main reason for fecal sac removal. In contrast, the attraction of flies to nestling feces, the elevation of the immune response of chicks, and the recently described antimicrobial function of the mucous covering of fecal sacs suggest that microorganisms could be responsible of this important form of parental care behavior (microbial hypothesis).

Nest site selection by Kentish plover suggests a trade-off between nest-crypsis and predator detection strategies.

PubMed

Gómez-Serrano, Miguel Ángel; López-López, Pascual

2014-01-01

Predation is one of the main causes of adult mortality and breeding failure for ground-nesting birds. Micro-habitat structure around nests plays a critical role in minimizing predation risk. Plovers nest in sites with little vegetation cover to maximize the incubating adult visibility, but many studies suggest a trade-off between nest-crypsis and predator detection strategies. However, this trade-off has not been explored in detail because methods used so far do not allow estimating the visibility with regards to critical factors such as slope or plant permeability to vision. Here, we tested the hypothesis that Kentish plovers select exposed sites according to a predator detection strategy, and the hypothesis that more concealed nests survive longer according to a crypsis strategy. To this end, we obtained an accurate estimation of the incubating adult's field of vision through a custom built inverted periscope. Our results showed that plovers selected nest sites with higher visibility than control points randomly selected with regards to humans and dogs, although nests located in sites with higher vegetation cover survived longer. In addition, the flushing distance (i.e., the distance at which incubating adults leave the nest when they detect a potential predator) decreased with vegetation cover. Consequently, the advantages of concealing the nest were limited by the ability to detect predators, thus indirectly supporting the existence of the trade-off between crypsis and predator detection. Finally, human disturbance also constrained nest choice, forcing plovers to move to inland sites that were less suitable because of higher vegetation cover, and modulated flushing behavior, since plovers that were habituated to humans left their nests closer to potential predators. This constraint on the width of suitable breeding habitat is particularly relevant for the conservation of Kentish Plover in sand beaches, especially under the current context of coastal regression and increase of recreational activities.

Nest Site Selection by Kentish Plover Suggests a Trade-Off between Nest-Crypsis and Predator Detection Strategies

PubMed Central

Gómez-Serrano, Miguel Ángel; López-López, Pascual

2014-01-01

Predation is one of the main causes of adult mortality and breeding failure for ground-nesting birds. Micro-habitat structure around nests plays a critical role in minimizing predation risk. Plovers nest in sites with little vegetation cover to maximize the incubating adult visibility, but many studies suggest a trade-off between nest-crypsis and predator detection strategies. However, this trade-off has not been explored in detail because methods used so far do not allow estimating the visibility with regards to critical factors such as slope or plant permeability to vision. Here, we tested the hypothesis that Kentish plovers select exposed sites according to a predator detection strategy, and the hypothesis that more concealed nests survive longer according to a crypsis strategy. To this end, we obtained an accurate estimation of the incubating adult's field of vision through a custom built inverted periscope. Our results showed that plovers selected nest sites with higher visibility than control points randomly selected with regards to humans and dogs, although nests located in sites with higher vegetation cover survived longer. In addition, the flushing distance (i.e., the distance at which incubating adults leave the nest when they detect a potential predator) decreased with vegetation cover. Consequently, the advantages of concealing the nest were limited by the ability to detect predators, thus indirectly supporting the existence of the trade-off between crypsis and predator detection. Finally, human disturbance also constrained nest choice, forcing plovers to move to inland sites that were less suitable because of higher vegetation cover, and modulated flushing behavior, since plovers that were habituated to humans left their nests closer to potential predators. This constraint on the width of suitable breeding habitat is particularly relevant for the conservation of Kentish Plover in sand beaches, especially under the current context of coastal regression and increase of recreational activities. PMID:25208045

Allometric Scaling of Patrolling Rate and Nest Volume in Constrictotermes cyphergaster Termites: Hints on the Settlement of Inquilines

PubMed Central

DeSouza, Og; Araújo, Ana Paula Albano; Florencio, Daniela Faria; Rosa, Cassiano Sousa; Marins, Alessandra; Costa, Diogo Andrade; Rodrigues, Vinicius Barros; Cristaldo, Paulo Fellipe

2016-01-01

Structural and functional traits of organisms are known to be related to the size of individuals and to the size of their colonies when they belong to one. Among such traits, propensity to inquilinism in termites is known to relate positively to colony size. Larger termitaria hold larger diversity of facultative inquilines than smaller nests, whereas obligate inquilines seem unable to settle in nests smaller than a threshold volume. Respective underlying mechanisms, however, remain hypothetical. Here we test one of such hypotheses, namely, that nest defence correlates negatively to nest volume in Constrictotermes cyphergaster termites (Termitidae: Nasutitermitinae). As a surrogate to defence, we used ‘patrolling rate’, i.e., the number of termite individuals attending per unit time an experimentally damaged spot on the outer wall of their termitaria. We found that patrolling rate decayed allometrically with increasing nest size. Conspicuously higher patrolling rates occurred in smaller nests, while conspicuously lower rates occurred in larger nests presenting volumes in the vicinity of the threshold value for the establishment of inquilinism. This could be proven adaptive for the host and guest. At younger nest age, host colonies are smaller and presumably more vulnerable and unstable. Enhanced defence rates may, hence, prevent eventual risks to hosts from inquilinism at the same time that it prevents inquilines to settle in a still unstable nest. Conversely, when colonies grow and maturate enough to stand threats, they would invest in priorities other than active defence, opening an opportunity for inquilines to settle in nests which are more suitable or less risky. Under this two-fold process, cohabitation between host and inquiline could readily stabilize. PMID:26808197

Weather radar data correlate to hail-induced mortality in grassland birds

USGS Publications Warehouse

Carver, Amber; Ross, Jeremy D.; Augustine, David J.; Skagen, Susan K.; Dwyer, Angela M.; Tomback, Diana F.; Wunder, Michael B.

2017-01-01

Small-bodied terrestrial animals such as songbirds (Order Passeriformes) are especially vulnerable to hail-induced mortality; yet, hail events are challenging to predict, and they often occur in locations where populations are not being studied. Focusing on nesting grassland songbirds, we demonstrate a novel approach to estimate hail-induced mortality. We quantify the relationship between the probability of nests destroyed by hail and measured Level-III Next Generation Radar (NEXRAD) data, including atmospheric base reflectivity, maximum estimated size of hail and maximum estimated azimuthal wind shear. On 22 June 2014, a hailstorm in northern Colorado destroyed 102 out of 203 known nests within our research site. Lark bunting (Calamospiza melanocorys) nests comprised most of the sample (n = 186). Destroyed nests were more likely to be found in areas of higher storm intensity, and distributions of NEXRAD variables differed between failed and surviving nests. For 133 ground nests where nest-site vegetation was measured, we examined the ameliorative influence of woody vegetation, nest cover and vegetation density by comparing results for 13 different logistic regression models incorporating the independent and additive effects of weather and vegetation variables. The most parsimonious model used only the interactive effect of hail size and wind shear to predict the probability of nest survival, and the data provided no support for any of the models without this predictor. We conclude that vegetation structure may not mitigate mortality from severe hailstorms and that weather radar products can be used remotely to estimate potential for hail mortality of nesting grassland birds. These insights will improve the efficacy of grassland bird population models under predicted climate change scenarios.

Wintering area DDE source to migratory white-faced ibis revealed by satellite telemetry and prey sampling.

PubMed

Yates, Michael A; Fuller, Mark R; Henny, Charles J; Seegar, William S; Garcia, Jaqueline

2010-01-01

Locations of contaminant exposure for nesting migratory species are difficult to fully understand because of possible additional sources encountered during migration or on the wintering grounds. A portion of the migratory white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada continues to be exposed to dichloro-diphenyldichloro-ethylene (DDE) with no change, which is unusual, observed in egg concentrations between 1985 and 2000. About 45-63% of the earliest nesting segment shows reduced reproductive success correlated with elevated egg concentrations of >4 microg/g wet weight (ww). Local prey (primarily earthworms) near nests contained little DDE so we tracked the migration and wintering movements of 20 adult males during 2000-2004 to determine the possible source. At various wintering sites, we found a correlation (r (2) = 0.518, P = 0.0125, N = 11) between DDE in earthworm composites and DDE in blood plasma of white-faced ibis wintering there, although the plasma was collected on their breeding grounds soon after arrival. The main source of DDE was wintering areas in the Mexicali Valley of Baja California Norte, Mexico, and probably the adjacent Imperial Valley, California, USA. This unusual continuing DDE problem for white-faced ibis is associated with: the long-term persistence in soil of DDE; the earthworms' ability to bioconcentrate DDE from soil; the proclivity of white-faced ibis to feed on earthworms in agricultural fields; the species's extreme sensitivity to DDE in their eggs; and perhaps its life history strategy of being a "capital breeder". We suggest surveying and sampling white-faced ibis eggs at nesting colonies, especially at Carson Lake, to monitor the continuing influence of DDE.

Reproductive success of the Black-crowned Night Heron at Alcatraz Island, San Francisco Bay, California, 1990-2002

USGS Publications Warehouse

Hothem, Roger L.; Hatch, Daphne

2004-01-01

Nesting chronology, habitat use, subcolony use, and hatchability were documented for the Black-crowned Night Heron (Nycticorax nycticorax) nesting at Alcatraz Island, San Francisco Bay, California during 1990-2002. Reproductive success was estimated using the Mayfield method and compared among years. Totals of monitored nests per year ranged from 68 in 2001 to 341 in 1996, with a trend of declining numbers since 1996. An increase in numbers of the Western Gull (Larus occidentalis), the Black-crowned Night Heron’s primary competitor, occurred during the same period. Overall reproductive success of the Black-crowned Night Heron at Alcatraz Island was below the 13-year average of 56.4% since 1996. During the study, the average number of chicks fledged per nest each year ranged from 0.46 to 1.27, which is less than the two chicks per nest suggested as a requirement for a sustained population. Embryos in five of 187 failed Black-crowned Night Heron eggs were deformed. In 1990 and 1991, eggs were analyzed for a wide range of contaminants, but none appeared to be sufficiently elevated to have caused the observed deformities. Based on these relatively low levels of contaminants, a high hatchability rate (94.5%), and relatively low levels of embryotoxicity, contaminants did not appear to significantly affect Black-crowned Night Heron reproduction at Alcatraz Island. However, predation by the Common Raven (Corvus corax) and Western Gull, interspecific competition with the Western Gull, habitat deterioration, and possible human disturbance are likely factors contributing to the decline in Black-crowned Night Heron reproductive success on Alcatraz Island in recent years.

Wintering area DDE source to migratory white-faced ibis revealed by satellite telemetry and prey sampling

USGS Publications Warehouse

Yates, M.A.; Fuller, M.R.; Henny, C.J.; Seegar, W.S.; Garcia, Jorge H.

2010-01-01

Locations of contaminant exposure for nesting migratory species are difficult to fully understand because of possible additional sources encountered during migration or on the wintering grounds. A portion of the migratory white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada continues to be exposed to dichloro-diphenyldichloro-ethylene (DDE) with no change, which is unusual, observed in egg concentrations between 1985 and 2000. About 45-63% of the earliest nesting segment shows reduced reproductive success correlated with elevated egg concentrations of >4 ??g/g wet weight (ww). Local prey (primarily earthworms) near nests contained little DDE so we tracked the migration and wintering movements of 20 adult males during 2000-2004 to determine the possible source. At various wintering sites, we found a correlation (r 2 = 0.518, P = 0.0125, N = 11) between DDE in earthworm composites and DDE in blood plasma of white-faced ibis wintering there, although the plasma was collected on their breeding grounds soon after arrival. The main source of DDE was wintering areas in the Mexicali Valley of Baja California Norte, Mexico, and probably the adjacent Imperial Valley, California, USA. This unusual continuing DDE problem for white-faced ibis is associated with: the long-term persistence in soil of DDE; the earthworms' ability to bioconcentrate DDE from soil; the proclivity of white-faced ibis to feed on earthworms in agricultural fields; the species's extreme sensitivity to DDE in their eggs; and perhaps its life history strategy of being a "capital breeder". We suggest surveying and sampling white-faced ibis eggs at nesting colonies, especially at Carson Lake, to monitor the continuing influence of DDE. ?? 2009 Springer Science+Business Media, LLC.

Discovering the Giant Nest Architecture of Grass-Cutting Ants, Atta capiguara (Hymenoptera, Formicidae)

PubMed Central

Forti, Luiz Carlos; Protti de Andrade, Ana Paula; Camargo, Roberto da Silva; Caldato, Nadia; Moreira, Aldenise Alves

2017-01-01

Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from a fragment of Cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found distant from the mound of loose soil and were spaced apart and distributed laterally at the soil profile. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers were separated and distant. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara. PMID:28350352

Processing of hierarchical syntactic structure in music.

PubMed

Koelsch, Stefan; Rohrmeier, Martin; Torrecuso, Renzo; Jentschke, Sebastian

2013-09-17

Hierarchical structure with nested nonlocal dependencies is a key feature of human language and can be identified theoretically in most pieces of tonal music. However, previous studies have argued against the perception of such structures in music. Here, we show processing of nonlocal dependencies in music. We presented chorales by J. S. Bach and modified versions in which the hierarchical structure was rendered irregular whereas the local structure was kept intact. Brain electric responses differed between regular and irregular hierarchical structures, in both musicians and nonmusicians. This finding indicates that, when listening to music, humans apply cognitive processes that are capable of dealing with long-distance dependencies resulting from hierarchically organized syntactic structures. Our results reveal that a brain mechanism fundamental for syntactic processing is engaged during the perception of music, indicating that processing of hierarchical structure with nested nonlocal dependencies is not just a key component of human language, but a multidomain capacity of human cognition.

The Design of Cluster Randomized Trials with Random Cross-Classifications

ERIC Educational Resources Information Center

Moerbeek, Mirjam; Safarkhani, Maryam

2018-01-01

Data from cluster randomized trials do not always have a pure hierarchical structure. For instance, students are nested within schools that may be crossed by neighborhoods, and soldiers are nested within army units that may be crossed by mental health-care professionals. It is important that the random cross-classification is taken into account…

Computing Power of Tests of the Variance of Treatment Effects in Designs with Two Levels of Nesting

ERIC Educational Resources Information Center

Konstantopoulos, Spyros

2008-01-01

Experiments that involve nested structures may assign treatment conditions either to entire groups (such as classrooms or schools) or individuals within groups (such as students). Although typically the interest in field experiments is in determining the significance of the overall treatment effect, it is equally important to examine the…

Latent Variable Regression 4-Level Hierarchical Model Using Multisite Multiple-Cohorts Longitudinal Data. CRESST Report 801

ERIC Educational Resources Information Center

Choi, Kilchan

2011-01-01

This report explores a new latent variable regression 4-level hierarchical model for monitoring school performance over time using multisite multiple-cohorts longitudinal data. This kind of data set has a 4-level hierarchical structure: time-series observation nested within students who are nested within different cohorts of students. These…

Avian nest box selection and nest success in burned and unburned southwestern riparian forests

Treesearch

D. Max Smith; Jeffrey F. Kelly; Deborah M. Finch

2007-01-01

Riparian forest communities in the southwestern United States were historically structured by a disturbance regime of annual flooding. In recent decades, however, frequency of flooding has decreased and frequency of wildfires has increased. Riparian forests provide important breeding habitat for a large variety of bird species, and the effects of this altered...

Changes in respiratory structure and function during post-diapause development in the alfalfa leafcutting bee, Megachile rotundata

USDA-ARS?s Scientific Manuscript database

Megachile rotundata, the alfalfa leafcutting bee, is a solitary, cavity-nesting bee. M. rotundata develop from eggs laid inside brood cells constructed from leaf pieces and placed in series in an existing cavity. Due to the cavity nesting behavior of M. rotundata, developing bees may experience hyp...

Toward Skillful Subseasonal Prediction of North Atlantic Hurricanes with regionally-refined GFDL HiRAM

NASA Astrophysics Data System (ADS)

Gao, K.; Harris, L.; Chen, J. H.; Lin, S. J.

2017-12-01

Skillful subseasonal prediction of hurricane activity (from two weeks to less than a season) is important for early preparedness and reducing the hurricane damage in coastal regions. In this study, we will present evaluations of the performance of GFDL HiRAM (High-Resolution Atmospheric Model) for the simulation and prediction of the North Atlantic hurricane activity on the sub-seasonal time scale. A series of sub-seasonal (30-day duration) retrospective predictions were performed over the years 2000-2014 using two configurations of HiRAM: a) global uniform 25km-resolution grid and b) two-way nested grid with a 8km-resolution nest over North Atlantic. The analysis of hurricane structure from the two sets of simulations indicates the two-way-nesting method is an efficient way to improve the representation of hurricanes in global models: the two-way nested configuration produces realistic hurricane inner-core size and structure, which leads to improved lifetime maximum intensity distribution. Both configurations show very promising performance in the subseasonal hurricane genesis prediction, but the two-way nested configuration shows better performance in the prediction of major hurricane (Categories 3-5) activity because of the improved intensity simulation. We will also present the analysis of how the phase and magnitude of MJO, as well as the initial SST anomaly affect the model's prediction skill.

Development of furnished cages for laying hens.

PubMed

Appleby, M C; Walker, A W; Nicol, C J; Lindberg, A C; Freire, R; Hughes, B O; Elson, H A

2002-09-01

1. A 3-year trial was carried out of cages for laying hens, occupying a full laying house. The main cage designs used were 5000 cm2 in area, 50 cm high at the rear and furnished with nests and perches. F cages had a front rollaway nest at the side, lined with artificial turf. FD cages also had a dust bath containing sand over the nest. H cages had two nest hollows at the side, one in front of the other. They were compared with conventional cages 2500 cm2 in area and 38 cm high at the rear. 2. Cages were stocked with from 4 to 8 ISA Brown hens per cage, resulting in varied allowances of area, feeder and perch per bird. No birds were beak trimmed. In F and FD cages two further treatments were applied: nests and dust baths were sometimes fitted with gates to exclude birds from dust baths in the morning and from both at night; elevated food troughs, with a lip 33 cm above the cage floor, were compared with standard troughs. 3. Management of the house was generally highly successful, with temperature control achieved by ventilation. Egg production was above breeders' standards and not significantly affected by cage design. More eggs per bird were collected when there were fewer birds per cage but food consumption also then tended to be higher. 4. The number of downgraded eggs was variable, with some tendency for more in furnished cages. Eggs laid in dust baths were often downgraded. Those laid at the back of the cage were frequently dirty because of accumulation of droppings. H nests were unsuccessful, with less than 50% of eggs laid in the nest hollows. However, up to 93% of eggs were laid in front rollaways, and few of these were downgraded. 5. Feather and foot damage were generally less in furnished than in conventional cages, greater where there were more birds per cage. With an elevated food trough there was less feather damage but more overgrowth of claws. In year 2, mortality was greater in cages with more birds. 6. Pre-laying behaviour was mostly settled in front rollaway nests. Dust baths were used more for pecking and scratching than for dust bathing. Comfort behaviour was more frequent in furnished cages than conventional, although still not frequent. Locomotion was strongly affected by number of birds per cage or by space per bird, being reduced by crowding. Most birds perched at night except in one treatment providing only 10.7 cm perch per bird. 7. Behaviour was more unrestricted and varied, and physical condition was better, in furnished than in conventional cages. However, egg production will cost more in furnished cages, partly because more eggs are downgraded. Dust baths must be fitted with gates that the birds cannot open from outside, but gates for nest boxes were found unnecessary. If a low perch is fitted it must be far enough from the back of the cage for birds to walk there. 8. Where there was less space per bird (more birds per cage) than the requirements in the 1999 European Commission Directive on laying hens, there were: fewer eggs per hen, but still above the breeders' target; lower food consumption; more feather and foot damage, but less than in conventional cages; higher mortality in one trial out of three; less freedom of movement. However, the results were still very good even with 8 birds per cage, and support the principle that furnished cages provide an acceptable way of protecting the welfare of laying hens.

Measuring the effect of mercury exposure on common loon productivity in Wisconsin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, M.W.; Hartigan, J.; Woodford, J.

1994-12-31

In 1991, the Wisconsin DNR conducted a pilot study to determine the extent of mercury (Hg) exposure in common loons (Gavia immer) breeding in Wisconsin. Loons are at risk to elevated mercury exposure in Wisconsin because they often nest on acidified, low alkalinity lakes. Fish from these lakes bioaccumulate methyl-Hg to a greater extent than biota from neutral pH lakes. Using nightlighting techniques, 35 adult loons were captured on 22 northern Wisconsin lakes (pH = 5.0--8.7) in 1991. Blood and feather samples were collected for Hg analysis. There was a highly significant negative linear relationship between adult loon blood clotmore » Hg and lake pH (r{sup 2} = 0.38, F = 15.27, P < 0.001); indicating loons nesting on low pH lakes receive greater mercury exposure than loons nesting on neutral pH lakes. The relationship was greater amongst adult males (r{sup 2} = 0.56) than among adult females (r{sup 2} = 0.36). The research effort was expanded in 1992 and 1993; 253 loons have been captured to date on 62 lakes in northern Wisconsin. The mercury content of feather and blood samples is being measured. Individual loons were also fitted with unique colored leg bands. Reproductive performance, annual return rates, and nesting behavior of adult loons with the greatest Hg exposure is being compared to that of adult loons with the least Hg exposure. The preliminary results from 1991--93 field seasons will be presented.« less

Association between PCBs and lower embryonic weight in black-crowned night herons in San Francisco Bay

USGS Publications Warehouse

Hoffman, D.J.; Rattner, B.A.; Bunck, C.M.; Krynitsky, A.J.; Ohlendorf, H.M.; Lowe, Roy W.

1986-01-01

Reproductive problems, including congenital malformations, reduced hatching success, and decreased survival of hatchlings, have been observed in colonial-nesting water birds at the San Francisco Bay National Wildlife Refuge (SFBNWR). Twenty-four black-crowned night heron (Nycticorax nycticorax) eggs were collected from SFBNWR in 1983. Twelve of these were collected from separate nests when late-stage embryos were pipping, and an additional egg was randomly collected from each nest for organochlorine analysis. Overt anomalies and skeletal defects were not apparent. Embryonic weights (with partially absorbed yolk sacs removed) were 15% lower (p lt 0.05) in SFBNWR embryos compared to control embryos from the Patuxent Wildlife Research Center (PWRC). Crown-rump length and femur length were shorter for SFBNWR embryos. The geometric mean polychlorinated biphenyl (PCB) concentration in SFBNWR eggs was 4.1 ppm wet weight, with a range of 0.8-52.0 ppm. A negative correlation (r = - 0.61; p lt 0.05) existed between embryonic weight and log-transformed PCB residues in whole eggs collected from the same nest at SFBNWR, suggesting a possible impact of PCBs on embryonic growth. A correlation with embryonic weight did not occur for DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) residues. Liver microsomal aryl hydrocarbon hydroxylase activity was neither significantly elevated nor correlated with PCB, DDE, or PCB plus DDE log-transformed residues. It is unknown whether the apparent association between PCBs and lower weight is persistent through hatching.

On the mound of Macrotermes michaelseni as an organ of respiratory gas exchange.

PubMed

Turner, J S

2001-01-01

Patterns and rates of air movements in the mounds and nests of Macrotermes michaelseni were studied using tracer methods. Wind is a significant source of energy for powering nest ventilation, despite the mound being a completely enclosed structure. Nests are ventilated by a tidal movement of air driven by temporal variation in wind speed and wind direction. Density gradients sufficiently steep to drive bulk flow by natural convection will be rare. However, metabolism-induced buoyant forces may interact with wind energy in a way that promotes homeostasis of the mound atmosphere.

Local Individual Preferences for Nest Materials in a Passerine Bird

PubMed Central

Mennerat, Adèle; Perret, Philippe; Lambrechts, Marcel M.

2009-01-01

Background Variation in the behavioural repertoire of animals is acquired by learning in a range of animal species. In nest-building birds, the assemblage of nest materials in an appropriate structure is often typical of a bird genus or species. Yet plasticity in the selection of nest materials may be beneficial because the nature and abundance of nest materials vary across habitats. Such plasticity can be learned, either individually or socially. In Corsican populations of blue tits Cyanistes caeruleus, females regularly add in their nests fragments of several species of aromatic plants during the whole breeding period. The selected plants represent a small fraction of the species present in the environment and have positive effects on nestlings. Methodology/Principal Findings We investigated spatiotemporal variations of this behaviour to test whether the aromatic plant species composition in nests depends on 1) plant availability in territories, 2) female experience or 3) female identity. Our results indicate that territory plays a very marginal role in the aromatic plant species composition of nests. Female experience is not related to a change in nest plant composition. Actually, this composition clearly depends on female identity, i.e. results from individual preferences which, furthermore, are repeatable both within and across years. A puzzling fact is the strong difference in plant species composition of nests across distinct study plots. Conclusions/Significance This study demonstrates that plant species composition of nests results from individual preferences that are homogeneous within study plots. We propose several hypotheses to interpret this pattern of spatial variation before discussing them in the light of preliminary results. As a conclusion, we cannot exclude the possibility of social transmission of individual preferences for aromatic plants. This is an exciting perspective for further work in birds, where nest construction behaviour has classically been considered as a stereotypic behaviour. PMID:19337365

High-resolution angle-resolved photoemission study of electronic structure and charge-density wave formation in HoTe3

NASA Astrophysics Data System (ADS)

Liu, Guodong; Wang, Chenlu; Zhang, Yan; Hu, Bingfeng; Mou, Daixiang; Yu, Li; Zhao, Lin; Zhou, Xingjiang; Wang, Nanlin; Chen, Chuangtian; Xu, Zuyan

We performed high-resolution angle-resolved photoemission spectroscopy (ARPES) measurement on high quality crystal of HoTe3, an intriguing quasi-two-dimensional rare-earth-element tritelluride charge-density-wave (CDW) compound. The main features of the electronic structure in this compound are established by employing a quasi-CW laser (7eV) and a helium discharging lamp (21.22 eV) as excitation light sources. It reveals many bands back folded according to the CDW periodicity and two incommensurate CDW gaps created by perpendicular Fermi surface (FS) nesting vectors. A large gap is found to open in well nested regions of the Fermi surface sheets, whereas other Fermi surface sections with poor nesting remain ungapped. In particular, some peculiar features are identified by using our ultra-high resolution and bulk sensitive laser-ARPES.

[Nesting habitat characterization for Amazona oratrix (Psittaciformes: Psittacidae) in the Central Pacific, Mexico].

PubMed

Monterrubio-Rico, Tiberio C; Álvarez-Jara, Margarito; Tellez-Garcia, Loreno; Tena-Morelos, Carlos

2014-09-01

The nesting requirements of the Yellow-headed Parrot (Amazona oratrix) are poorly understood, despite their broad historical distribution, high demand for pet trade and current endangered status. Information concerning their nesting requirements is required in order to design specific restoration and conser- vation actions. To assess this, we studied their nesting ecology in the Central Pacific, Michoacan, Mexico during a ten year period. The analyzed variables ranged from local scale nest site characteristics such as nesting tree species, dimensions, geographic positions, diet and nesting forest patches structure, to large scale features such as vegetation use and climatic variables associated to the nesting tree distributions by an ecological niche model using Maxent. We also evaluated the parrot tolerance to land management regimes, and compared the Pacific nest trees with 18 nest trees recorded in an intensively managed private ranch in Tamaulipas, Gulf of Mexico. Parrots nested in tall trees with canopy level cavities in 92 nest-trees recorded from 11 tree species. The 72.8% of nesting occurred in trees of Astronium graveolens, and Enterolobium cyclocarpum which qualified as key- stone trees. The forests where the parrots nested, presented a maximum of 54 tree species, 50% of which were identified as food source; besides, these areas also had a high abundance of trees used as food supply. The lowest number of tree species and trees to forage occurred in an active cattle ranch, whereas the highest species rich- ness was observed in areas with natural recovery. The nesting cavity entrance height from above ground of the Pacific nesting trees resulted higher than those found in the Gulf of Mexico. We hypothesize that the differences may be attributed to Parrot behavioral differences adapting to differential poaching pressure and cavity avail- ability. Nesting trees were found in six vegetation types; however the parrots preferred conserved and riparian semi-deciduous forest for nesting, with fewer nests in deciduous forest, while nesting in transformed agricultural fields was avoided. The main climatic variables associated with the potential distribution of nests were: mean temperature of wettest quarter, mean diurnal temperature range, and precipitation of wettest month. Suitable cli- matic conditions for the potential presence of nesting trees were present in 61% of the region; however, most of the area consisted of tropical deciduous forests (55.8%), while semi-deciduous tropical forests covered only 17% of the region. These results indicated the importance to conserve semi-deciduous forests as breeding habitats for the Yellow-headed Parrot, and revealed the urgent need to implement conservation and restoration actions. These should include a total ban of land use change in tropical semi-deciduous forest areas, and for selective logging of all keystone tree species; besides, we recommend the establishment of wildlife sanctuaries in important nesting areas, and a series of tropical forest restoration programs in the Central Pacific coast.

Loneliness and depression among rural empty-nest elderly adults in Liuyang, China: a cross-sectional study

PubMed Central

Wang, Guojun; Hu, Mi; Xiao, Shui-yuan; Zhou, Liang

2017-01-01

Objective To compare loneliness, depressive symptoms and major depressive episodes between empty-nest and not-empty-nest older adults in rural areas of Liuyang city, Hunan, China. Methods A cross-sectional multi-stage random cluster survey was conducted from November 2011 to April 2012 in Liuyang, China. A total of 839 rural older residents aged 60 or above completed the survey (response rate 97.6%). In line with the definition of empty nest, 25 participants who had no children were excluded from the study, while the remaining 814 elderly adults with at least one child were included for analysis. Loneliness and depressive symptoms in rural elderly parents were assessed using the short-form UCLA Loneliness Scale (ULS-6) and the Geriatric Depression Scale (GDS). Major depressive episodes were diagnosed using the Structured Clinical Interview for DSM-IV (SCID-I). Results Significant differences were found between empty-nest and not-empty-nest older adults regarding loneliness (16.19±3.90 vs. 12.87±3.02, Cohen’s d=0.97), depressive symptoms (8.50±6.26 vs. 6.92±5.19, Cohen’s d=0.28) and the prevalence of major depressive episodes (10.1% vs. 4.6%) (all p<0.05). After controlling for demographic characteristics and physical disease, the differences in loneliness, depressive symptoms and major depressive episodes remained significant. Path analysis showed that loneliness mediated the relationship between empty-nest syndrome and depressive symptoms and major depressive episodes. Conclusion Loneliness and depression are more severe among empty-nest than not-empty-nest rural elderly adults. Loneliness was a mediating variable between empty-nest syndrome and depression. PMID:28988166

Field Margins, Foraging Distances and Their Impacts on Nesting Pollinator Success

PubMed Central

Rands, Sean A.; Whitney, Heather M.

2011-01-01

The areas of wild land around the edges of agricultural fields are a vital resource for many species. These include insect pollinators, to whom field margins provide both nest sites and important resources (especially when adjacent crops are not in flower). Nesting pollinators travel relatively short distances from the nest to forage: most species of bee are known to travel less than two kilometres away. In order to ensure that these pollinators have sufficient areas of wild land within reach of their nests, agricultural landscapes need to be designed to accommodate the limited travelling distances of nesting pollinators. We used a spatially-explicit modelling approach to consider whether increasing the width of wild strips of land within the agricultural landscape will enhance the amount of wild resources available to a nesting pollinator, and if it would impact differently on pollinators with differing foraging strategies. This was done both by creating field structures with a randomised geography, and by using landscape data based upon the British agricultural landscape. These models demonstrate that enhancing field margins should lead to an increase in the availability of forage to pollinators that nest within the landscape. With the exception of species that only forage within a very short range of their nest (less than 125 m), a given amount of field margin manipulation should enhance the proportion of land available to a pollinator for foraging regardless of the distance over which it normally travels to find food. A fixed amount of field edge manipulation should therefore be equally beneficial for both longer-distance nesting foragers such as honeybees, and short-distance foragers such as solitary bees. PMID:21991390

Occurrence and Distribution of Mercury in the SurficialAquifer, Long Neck Peninsula, Sussex County, Delaware, 2003-04

USGS Publications Warehouse

Koterba, Michael T.; Andres, A. Scott; Vrabel, Joseph; Crilley, Dianna M.; Szabo, Zoltan; DeWild, John F.; Aiken, George R.; Reyes-Padro, Betzaida

2006-01-01

In January 2001, mercury (Hg) was detected (500 nanograms per liter, ng/L, or greater) in the distribution system of the Long Neck Water Company (LNWC), Pot Nets, Delaware. By April 2001, two LNWC production wells had been taken off-line because discharge concentrations of total mercury (HgT) either had exceeded or approached the Federal limit of 2,000 ng/L. From October 2003 through January 2005, the U.S. Geological Survey, Delaware Geological Survey, and Delaware Department of Natural Resources and Environmental Control conducted a cooperative study to (a) determine if the Hg contamination was widespread, (b) identify possible forms of Hg in ground water, and (c) examine Hg occurrence in relation to (geo)chemical conditions and characteristics of ground water and sediment in the surficial aquifer on the Long Neck Peninsula, Sussex County, Delaware. An initial water-quality survey conducted with samples from 22 production wells revealed that concentrations of HgT in ground water in the surficial aquifer ranged from 0.11 to 1,820 ng/L. Shallow ground water (less than 120 feet below land surface) throughout most of the peninsula, including that which contained elevated concentrations of HgT (exceeding 100 ng/L), appeared to be affected by human activities. All samples contained volatile organic compounds (VOCs) and elevated nitrate-nitrogen (NO3-N, exceeding 0.4 milligrams per liter, mg/L). Most (16 of 22) samples had elevated specific conductance (SC, in excess of 100 microsiemens per centimeter at 25 degrees Celsius). Elevated concentrations of HgT, however, only occurred in five production wells in the Pot Nets Bayside and Lakeside communities. The vertical distribution of HgT in shallow ground water (less than 80 feet below land surface) was determined with samples collected at 5 to 6 vertical-nest short-screened (2 - 5-foot length) monitoring wells installed near Bayside and Lakeside production wells with the highest HgT concentrations (exceeding 1,000 ng/L). Elevated concentrations ofHgT (100-6,380 ng/L) occurred in the shallow aquifer near each well at different depths. Chemical analyses of selected soil, fill, and aquifer sediment samples, obtained during the installation of nested wells, indicated that little HgT occurred in soil or fill at either site (40 micrograms per kilogram, ?g/kg, or less). No HgT was detected (less than 20 ?g/kg) in aquifer sediment samples. These low HgT concentrations imply that neither the soil, fill, nor aquifer sediment was a likely source of the elevated Hg in ground water. Given Hg occurrence appeared to be a ground-water transport phenomenon, the forms of Hg in transport were investigated. Differences in HgT concentrations between raw and filtered (0.1- and (or) 0.4-absolute micrometer pore size) samples from nested wells were random in sign and similar in magnitude to the variability in measuring HgT attributed to field and laboratory methods (? 5-10 percent, for HgT concentrations exceeding 100 ng/L). Thus, Hg transport likely occurred in a dissolved or fine-colloidal nonparticulate phase. Methyl mercury (HgMe) only was detected at low concentrations (0.06 ng/L or less) in nested-well samples with low to moderate concentrations of HgT (less than 366 ng/L). Whether HgMe occurred at similar concentrations in samples with high HgT concentrations was unresolved due to a sample-matrix interference problem. Potential complex forms of Hg were investigated in relation to the occurrence of selected ligands (organic carbon, sulfide, and chloride concentrations) and geochemical conditions (for example, pH and dissolved oxygen concentrations). Only dissolved organic carbon (DOC) appeared directly related to Hg occurrence. Elevated concentrations of HgT and DOC co-occurred in ground water at both Pot Nets sites. The average concentration of DOC was about four times greater in samples from the Pot Nets wells with the highest HgT concentrations (exceeding 1,000 ng/L) than in most Pot Nets o

Mercury and other element exposure to tree swallows (Tachycineta bicolor) nesting on Lostwood National Wildlife Refuge, North Dakota

USGS Publications Warehouse

Custer, T.W.; Custer, Christine M.; Johnson, K.M.; Hoffman, D.J.

2008-01-01

Elevated mercury concentrations in water were reported in the prairie wetlands at Lostwood National Wildlife Refuge, ND. In order to determine whether wildlife associated with these wetlands was exposed to and then accumulated higher mercury concentrations than wildlife living near more permanent wetlands (e.g. lakes), tree swallow (Tachycineta bicolor) eggs and nestlings were collected from nests near seasonal wetlands, semi-permanent wetlands, and lakes. Mercury concentrations in eggs collected near seasonal wetlands were higher than those collected near semi-permanent wetlands or lakes. In contrast, mercury concentrations in nestling livers did not differ among wetland types. Mercury and other element concentrations in tree swallow eggs and nestlings collected from all wetlands were low. As suspected from these low concentrations, mercury concentrations in sample eggs were not a significant factor explaining the hatching success of the remaining eggs in each clutch.

Interpreting forest and grassland biome productivity utilizing nested scales of image resolution and biogeographical analysis

NASA Technical Reports Server (NTRS)

Iverson, Louis R.; Cook, Elizabeth A.; Graham, Robin L.; Olson, Jerry S.; Frank, Thomas; Ke, Ying; Treworgy, Colin; Risser, Paul G.

1987-01-01

This report summarizes progress made in our investigation of forest productivity assessment using TM and other biogeographical data during the third six-month period of the grant. Data acquisition and methodology hurdles are largely complete. Four study areas for which the appropriate TM and ancillary data were available are currently being intensively analyzed. Significant relationships have been found on a site by site basis to suggest that forest productivity can be qualitatively assessed using TM band values and site characteristics. Perhaps the most promising results relate TM unsupervised classes to forest productivity, with enhancement from elevation data. During the final phases of the research, multi-temporal and regional comparisons of results will be addressed, as well as the predictability of forest productivity patterns over a large region using TM data and/or TM nested within AVHRR data.

Variability in nest density, occupancy, and home range size of western bluebirds after forest treatments

Treesearch

Sarah Hurteau; Thomas Sisk; Brett Dickson; William Block

2010-01-01

Complex land use and fuels management histories have resulted in significant changes in composition, structure, and function of southwestern forests and subsequent changes in the extent and quality of wildlife habitats. We evaluated how several currently used fuel reduction treatments (e.g., mechanical thinning and prescribed fire alone and in combination) affect nest...

Impacts of flamingos on saline lake margin and shallow lacustrine sediments in the Kenya Rift Valley

NASA Astrophysics Data System (ADS)

Scott, Jennifer J.; Renaut, Robin W.; Owen, R. Bernhart

2012-11-01

Studies of modern, Holocene, and Pleistocene sediments around saline to hypersaline, alkaline Lake Bogoria and Lake Magadi show that evidence of flamingo activity in marginal areas of these lakes is nearly ubiquitous. Flamingos produce discrete structures such as webbed footprints (~ 9 cm long, ~ 11 cm wide) and nest mounds (~ 30 cm wide, ~ 20 cm high), and they also extensively rework sediments in delta front, delta plain, and shoreline areas. Large (~ 0.5-2 cm in diameter), pinched, 'bubble pores' and ped-like mud clumps are formed by the trampling and churning of wet clay-rich sediments in these settings. Flamingo nest mounds, although superficially similar to some thrombolite mounds, are typically internally structureless, unless formed on pre-existing sediments that preserve internal structures. The flamingo mounds consist of a dense, packed oval-shaped core, a surrounding 'body' of packed sediment, and an external layer with a ped-like texture of clumped mud. The nests may contain open holes from roots or feather shafts incorporated into the nest, and (or) burrows produced once the nests are abandoned. In areas with high densities of flamingos, lake margin sediments may be preferentially compacted, particularly at breeding sites, and become resistant to subaerial erosion and the effects of transgressive ravinement on time scales ranging from seasons to tens of thousands of years. The relatively well-compacted nest mounds and associated sediments also contribute to the stability of delta distributary channels during regressive-transgressive cycles, and can lead to the minor channelization of unconfined flows where currents are diverted around nest mounds. Pleistocene exhumed surfaces of relatively well-indurated lake margin sediments at Lake Bogoria and Lake Magadi that are interpreted as combined regressive and transgressive surfaces (flooding surface/sequence boundary) preserve evidence of flamingo activities, and are overlain by younger, porous lacustrine silts that preserve large bubble pores produced by flamingos.

Population responses to environmental change in a tropical ant: the interaction of spatial and temporal dynamics.

PubMed

Jackson, Doug; Vandermeer, John; Perfecto, Ivette; Philpott, Stacy M

2014-01-01

Spatial structure can have a profound, but often underappreciated, effect on the temporal dynamics of ecosystems. Here we report on a counterintuitive increase in the population of a tree-nesting ant, Azteca sericeasur, in response to a drastic reduction in the number of potential nesting sites. This surprising result is comprehensible when viewed in the context of the self-organized spatial dynamics of the ants and their effect on the ants' dispersal-limited natural enemies. Approximately 30% of the trees in the study site, a coffee agroecosystem in southern Mexico, were pruned or felled over a two-year period, and yet the abundance of the ant nests more than doubled over the seven-year study. Throughout the transition, the spatial distribution of the ants maintained a power-law distribution - a signal of spatial self organization - but the local clustering of the nests was reduced post-pruning. A cellular automata model incorporating the changed spatial structure of the ants and the resulting partial escape from antagonists reproduced the observed increase in abundance, highlighting how self-organized spatial dynamics can profoundly influence the responses of ecosystems to perturbations.

Population Responses to Environmental Change in a Tropical Ant: The Interaction of Spatial and Temporal Dynamics

PubMed Central

Jackson, Doug; Vandermeer, John; Perfecto, Ivette; Philpott, Stacy M.

2014-01-01

Spatial structure can have a profound, but often underappreciated, effect on the temporal dynamics of ecosystems. Here we report on a counterintuitive increase in the population of a tree-nesting ant, Azteca sericeasur, in response to a drastic reduction in the number of potential nesting sites. This surprising result is comprehensible when viewed in the context of the self-organized spatial dynamics of the ants and their effect on the ants’ dispersal-limited natural enemies. Approximately 30% of the trees in the study site, a coffee agroecosystem in southern Mexico, were pruned or felled over a two-year period, and yet the abundance of the ant nests more than doubled over the seven-year study. Throughout the transition, the spatial distribution of the ants maintained a power-law distribution – a signal of spatial self organization – but the local clustering of the nests was reduced post-pruning. A cellular automata model incorporating the changed spatial structure of the ants and the resulting partial escape from antagonists reproduced the observed increase in abundance, highlighting how self-organized spatial dynamics can profoundly influence the responses of ecosystems to perturbations. PMID:24842117

Microbiota-Dependent Marker TMAO Is Elevated in Silent Ischemia but Is Not Associated With First-Time Myocardial Infarction in HIV Infection.

PubMed

Haissman, Judith M; Knudsen, Andreas; Hoel, Hedda; Kjær, Andreas; Kristoffersen, Ulrik S; Berge, Rolf K; Katzenstein, Terese L; Svardal, Asbjørn; Ueland, Thor; Aukrust, Pål; Lebech, Anne-Mette; Nielsen, Susanne D; Trøseid, Marius

2016-02-01

HIV infection is associated with increased risk of coronary heart disease beyond that explained by traditional risk factors, and altered gut microbiota has been proposed as a potential trigger. Trimethylamine-N-oxide (TMAO) is a proatherogenic substance formed in the liver from trimethylamine, exclusively generated by gut microbiota from dietary phosphatidylcholine. We aimed to investigate whether TMAO is associated with subclinical and clinical coronary heart disease in HIV infection. Two previously described cohorts were examined as follows: (1) cross-sectional cohort of HIV-infected persons and uninfected controls with known atherosclerotic plaque burden as assessed by myocardial perfusion scintigraphy, coronary artery calcium score, and intima-media thickness and (2) nested case-control study of HIV-infected persons with first-time myocardial infarction (MI) compared with HIV-infected persons without MI, assessed at 4 time points from before initiation of antiretroviral therapy (ART) to last sample before the case's MI (median: 51, range: 0-239 days). There was no difference in plasma TMAO when comparing HIV-infected persons and uninfected controls. TMAO was elevated in HIV-infected persons with myocardial perfusion defects but was not associated with coronary artery calcium score, intima media thickness, or Framingham risk score. In the nested case control study, plasma TMAO was not associated with first-time MI. However, TMAO increased after ART introduction and was associated with the use of protease inhibitors in both cohorts. TMAO was elevated in HIV-infected persons with myocardial perfusion defects, but was not associated with first-time MI. Our data question TMAO as a useful biomarker of cardiovascular risk in HIV infection, at least in ART-treated individuals.

[Duration of the pre-nesting period and its relation with social organization in sandpipers (Charadrii, Aves) nesting in north-east Yakutia].

PubMed

Gavrilov, V V

2013-01-01

Investigations were carried out at two stations of Ornithological Unit, IBPN FEB RAS, located in Nizhnekolymsk District, Yakutia, starting from May 18-20 in 1984, 1985, 1987, 1988 and 1990. Duration of the pre-nesting period in 11 sandpiper species with different social organization was studied and compared with each other by allometric equations. As a characteristic of bird size the body mass was selected. Sandpipers come flying to the tundra at almost critical temperatures, to begin breeding as early as possible. Tining of breeding depends on birds feeding manner and the proximity to sites of overwintering. Duration of the pre-nesting period is invariable for every bird species and sex. There are sexual distinctions in time spent for the pre-nesting period in jointly-nesting sandpipers. The exponents in allometric equations that relate duration of the pre-nesting period with body mass are constant within a particular sex and differ between males and females. In different sexes, time spent for the pre-nesting period depends on mating, parental, and territorial systems. In sandpipers' males and females, this time is determined by the type of social organization. Relatively large sandpiper species seek to shortening of the pre-nesting period calendar time, which constrains their social organization. Monogamy and pair parental care lead to a necessity for spatial population structure to be controlled more strictly and maintained for a longer time. This, in turn, causes the increasing of males' time expenditures for such a behavior.

Origin and Loss of Nested LRRTM/α-Catenin Genes during Vertebrate Evolution

PubMed Central

Uvarov, Pavel; Kajander, Tommi; Airaksinen, Matti S.

2014-01-01

Leucine-rich repeat transmembrane neuronal proteins (LRRTMs) form in mammals a family of four postsynaptic adhesion proteins, which have been shown to bind neurexins and heparan sulphate proteoglycan (HSPG) glypican on the presynaptic side. Mutations in the genes encoding LRRTMs and neurexins are implicated in human cognitive disorders such as schizophrenia and autism. Our analysis shows that in most jawed vertebrates, lrrtm1, lrrtm2, and lrrtm3 genes are nested on opposite strands of large conserved intron of α-catenin genes ctnna2, ctnna1, and ctnna3, respectively. No lrrtm genes could be found in tunicates or lancelets, while two lrrtm genes are found in the lamprey genome, one of which is adjacent to a single ctnna homolog. Based on similar highly positive net charge of lamprey LRRTMs and the HSPG-binding LRRTM3 and LRRTM4 proteins, we speculate that the ancestral LRRTM might have bound HSPG before acquiring neurexins as binding partners. Our model suggests that lrrtm gene translocated into the large ctnna intron in early vertebrates, and that subsequent duplications resulted in three lrrtm/ctnna gene pairs present in most jawed vertebrates. However, we detected three prominent exceptions: (1) the lrrtm3/ctnna3 gene structure is absent in the ray-finned fish genomes, (2) the genomes of clawed frogs contain ctnna1 but lack the corresponding nested (lrrtm2) gene, and (3) contain lrrtm3 gene in the syntenic position but lack the corresponding host (ctnna3) gene. We identified several other protein-coding nested gene structures of which either the host or the nested gene has presumably been lost in the frog or chicken lineages. Interestingly, majority of these nested genes comprise LRR domains. PMID:24587117

Edge, height and visibility effects on nest predation by birds and mammals in the Brazilian cerrado

NASA Astrophysics Data System (ADS)

Dodonov, Pavel; Paneczko, Ingrid Toledo; Telles, Marina

2017-08-01

Edge influence is one of the main impacts in fragmented landscapes; yet, most of studies on edge influence have focused on high-contrast edges, and the impacts of low-contrast edges and narrow linear openings are less understood. Edge influence often affects bird nest predation, but these effects are not ubiquitous and may depend on characteristics such as nest height and visibility. We performed an experiment on nest predation in a migratory passerine, Elaenia chiriquensis (Lesser Elaenia; Passeriformes: Tyrannidae), in a savanna vegetation of the Brazilian Cerrado biome in South-Eastern Brazil. We used 89 real E. chiriquensis nests, collected during previous reproductive seasons, with two plasticine eggs in each, and randomly distributed them at two locations (edge - up to 20 m from a firebreak edge and interior - approx. 150-350 m from the edge) and two heights (low - 60-175 cm and high - 190-315 cm above ground). We also measured leaf and branch density around each nest. We performed this study on two 15-days campaigns, checking the nests every 2-3 days and removing those with predation marks. We sorted the predation marks into those made by birds, mammals, or unidentified predators, and used generalized linear models to assess the effects of location, height and leaf density on survival time and predator type. Only four nests had not been predated during the experiment; 55 nests were predated by birds, 7 by mammals, and 23 by unidentified predators. Low nests in the interior tended to have larger survival times whereas high nests at the edge tended to be more predated by birds and less predated by mammals. Thus, even a low-contrast (firebreak) edge may significantly increase nest predation, which is also affected by the nest's height, mainly due to predation by birds. These effects may be due to predator movement along the edge as well as to edge-related changes in vegetation structure. We suggest that higher-contrast edges which may also be used as movement conduits, for example powerline openings, may have even stronger effects, demanding further studies.

Reproductive ecology of American Oystercatchers nesting on shell rakes

USGS Publications Warehouse

Jodice, Patrick G.R.; Thibault, Janet M.; Collins, S.A.; Spinks, Mark D.; Sanders, Felicia J.

2014-01-01

Degradation of nesting habitat for coastal birds has led to the use of nontraditional nesting habitat. The American Oystercatcher (Haematopus palliatus) is listed as a "Species of High Concern'' by the U. S. Shorebird Conservation Plan and is declining in the southern portion of its U. S. breeding range, where ~ 50% of breeding oystercatchers nest on shell substrate instead of beachfront habitat. We measured daily survival rates during incubation and chick rearing in shell rake habitats over five breeding seasons in the Cape Romain region of South Carolina, USA. Of 354 nesting attempts monitored, 16.1% hatched at least one egg. During incubation, daily survival rate was 0.938, corresponding to 22.8% success to hatching (nest success). For broods, daily survival was 0.991, or 74.0% success from hatching to fledging. Productivity in the Cape Romain region is primarily being lost during the incubation phase, when nests are exposed to overwash and predation. Mobile chicks may, however, be able to avoid flood events or predators by relocating to higher or more protected portions of a shell rake. Based on comparative data for American Oystercatchers from elsewhere in their range, it does not appear that shell rakes in the Cape Romain region are inferior breeding habitat. Our data suggest that conservation actions targeting nest and chick loss from flooding and predation have the greatest opportunity to enhance reproductive success in this core breeding area, and that an assessment of the availability, structure, avian use, and protection status of shell rakes is warranted.

Nest site preferences of the Woodlark (Lullula arborea) and its association with artificial nest predation

NASA Astrophysics Data System (ADS)

Buehler, Roman; Bosco, Laura; Arlettaz, Raphaël; Jacot, Alain

2017-01-01

The Woodlark is an insectivorous bird, which is listed as a priority species in Switzerland. In Valais, a stronghold of this species in the country, the birds breed in intensively managed vineyards and show a preference for parcels with ground vegetation during territory establishment. As a ground-breeder, the species is highly vulnerable to nest predation by avian and mammal predators. The aims of our study were firstly to investigate nest site preferences of the woodlark within vineyards and secondly to compare the predation risk of artificial nests dependent of ground vegetation structure. Our results point out that the Woodlark prefers patches of tall and dense ground cover within vegetated vineyard parcels and avoids parcels that have been treated with herbicides. In a follow-up experiment we conducted a study comparing the predation rate of artificial nests between bare parcels (<20% vegetated area) and vegetated parcels (>40% vegetated area). Artificial nests equipped with one quail egg were distributed pairwise between two adjacent parcels that fulfilled the upper criteria and were monitored by trail cameras during 10-12 days. Predation rate was generally low (4 predation events) and only occurred in bare parcels. These data indicate that conspicuousness of avian nests may be decreased in vegetated parcels and that the amount of vegetation can lower the predation risk on ground breeding birds - another indication for the importance of ground vegetation for a successful conservation of the endangered Woodlark in Swiss vineyards.

A large accumulation of avian eggs from the late cretaceous of patagonia (Argentina) reveals a novel nesting strategy in mesozoic birds.

PubMed

Fernández, Mariela S; García, Rodolfo A; Fiorelli, Lucas; Scolaro, Alejandro; Salvador, Rodrigo B; Cotaro, Carlos N; Kaiser, Gary W; Dyke, Gareth J

2013-01-01

We report the first evidence for a nesting colony of mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m(2). These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods.

A Large Accumulation of Avian Eggs from the Late Cretaceous of Patagonia (Argentina) Reveals a Novel Nesting Strategy in Mesozoic Birds

PubMed Central

Fernández, Mariela S.; García, Rodolfo A.; Fiorelli, Lucas; Scolaro, Alejandro; Salvador, Rodrigo B.; Cotaro, Carlos N.; Kaiser, Gary W.; Dyke, Gareth J.

2013-01-01

We report the first evidence for a nesting colony of Mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m2. These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods. PMID:23613776

A critical evaluation of various methods for the analysis of flow-solid interaction in a nest of thin cylinders subjected to cross flows

NASA Technical Reports Server (NTRS)

Kim, Sang-Wook

1987-01-01

Various experimental, analytical, and numerical analysis methods for flow-solid interaction of a nest of cylinders subjected to cross flows are reviewed. A nest of cylinders subjected to cross flows can be found in numerous engineering applications including the Space Shuttle Maine Engine-Main Injector Assembly (SSME-MIA) and nuclear reactor heat exchangers. Despite its extreme importance in engineering applications, understanding of the flow-solid interaction process is quite limited and design of the tube banks are mostly dependent on experiments and/or experimental correlation equations. For future development of major numerical analysis methods for the flow-solid interaction of a nest of cylinders subjected to cross flow, various turbulence models, nonlinear structural dynamics, and existing laminar flow-solid interaction analysis methods are included.

Luminescence dating of anthropogenic features of the San Luis Valley, Colorado: from stone huts to stone walls

USGS Publications Warehouse

Mahan, Shannon; Donlan, Rebecca A.; Kardos, Barbara Maat

2015-01-01

The Snake Nest Wall site and the Crestone Stone Huts are in the northern San Luis Valley, Colorado, and provide a unique opportunity to date high-altitude archeological sites of unknown age and origin using optically stimulated luminescence (OSL). We sampled sediment underlying foundation stones of these structures to establish a chronological framework for each site's construction. OSL dating of the quartz grains directly under the Snake Nest Wall suggest that the stones and, therefore, the structure was most recently emplaced between 1855 and 1890 A.D. Dating of the sediment beneath the Crestone Stone Huts suggests the construction time of these huts is between 1860 and 1890 A.D. Analysis of the equivalent dose (DE) dispersion of the OSL samples at Snake Nest Wall and the Crestone Huts shows that the majority of sediments were fully bleached prior to deposition and the low scatter suggests that short-term or shallow alluvial processes were the dominant transport for sediments. In both cases, the OSL ages show that the construction was during very recent historical times, although it is likely that the Snake Nest Wall was rebuilt in the late 19th century. Further study is warranted at the Snake Nest Wall since it shows signs of greater antiquity and a continued presence of human use. The Crestone Huts are shown to be a product of railroad building during the boomtown days of Lucky and Crestone.

Demographic differences of black-capped vireos in 2 habitat types in central Texas

USGS Publications Warehouse

Noa, L.A.; Hirth, D.H.; Donovan, T.M.; Cimprich, D.

2007-01-01

To understand the effects of habitat selection, we analyzed differences in abundance, age structure, and nesting success of black-capped vireos (Vireo atricapilla) in 2 early successional habitat types found on Fort Hood, a 87,890-ha Military Reservation in central Texas, USA. These habitats were 1) large areas of continuously shrubby vegetation (both natural and mechanically made), referred to as shrubland habitat, and 2) anthropogenically created small patches of shrubby vegetation centered on one or several large trees, known locally as donut habitat. The objectives of our study were to determine whether there were differences in abundance, age structure, and daily nest survival in these 2 habitat types and to determine whether donut habitat is high- or low-quality habitat. Donut habitat had a lower abundance of vireos (half as many as shrubland/point count) and a higher percentage of second-year males, suggesting donut habitat was lower-quality habitat than shrubland. Analyses of daily nest survival indicated that habitat, nest height, and year were all important variables. Nests initiated in 2004, located in shrubland habitats, and higher from the ground were more likely to succeed. Our study provided evidence that habitat is a limiting factor for this federally endangered species. Because habitat is limiting, wildlife biologists at Fort Hood should focus on managing higher quality, contiguous shrubland habitat. Wildlife biologists should also continue to monitor areas of donut habitat to determine whether they represent potential population sinks.

Effects of leafy spurge infestation on grassland birds

USGS Publications Warehouse

Scheiman, D.M.; Bollinger, E.K.; Johnson, D.H.

2003-01-01

Grassland bird populations are declining. Invasive plant species may be contributing to these declines by altering habitat quality. However, the effects of invasive plants on grassland birds are largely unknown. Leafy spurge (Euphorbia esula) is an exotic, invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities of breeding birds, nest-site selection, and nest success in grasslands on the Sheyenne National Grassland (SNG), North Dakota, USA, 1999-2000. We categorized spurge-infested grasslands into 3 groups (low, medium, high), based on the area covered by spurge patches. We surveyed 75 100-m-radius circular points (25 in each group), and searched for nests in 6 16-ha plots (2 in each group). Grasshopper sparrow (Ammodramus savannarum) and savannah sparrow (Passerculus sandwichensis) densities were lower on high-spurge points than on low- and medium-spurge points. Bobolink (Dolichonyx oryzivorus) and western meadowlark (Sturnella neglecta) densities were not significantly different among spurge cover groups. Spurge cover did not appear to be an important factor in nest-site selection. However, western meadowlark nest success was positively associated with spurge cover. Vegetation structure is an important indicator of habitat quality and resource availability for grassland birds. Changes in vegetation structure caused by introduced plant species, such as spurge, can alter resource availability and hence affect bird community composition. Managers of spurge-infested grasslands should continue current spurge control measures to help prevent further declines in grassland habitat quality and grassland bird populations.

Conservation of forest birds: evidence of a shifting baseline in community structure.

PubMed

Rittenhouse, Chadwick D; Pidgeon, Anna M; Albright, Thomas P; Culbert, Patrick D; Clayton, Murray K; Flather, Curtis H; Huang, Chengquan; Masek, Jeffrey G; Stewart, Susan I; Radeloff, Volker C

2010-08-02

Quantifying changes in forest bird diversity is an essential task for developing effective conservation actions. When subtle changes in diversity accumulate over time, annual comparisons may offer an incomplete perspective of changes in diversity. In this case, progressive change, the comparison of changes in diversity from a baseline condition, may offer greater insight because changes in diversity are assessed over longer periods of times. Our objectives were to determine how forest bird diversity has changed over time and whether those changes were associated with forest disturbance. We used North American Breeding Bird Survey data, a time series of Landsat images classified with respect to land cover change, and mixed-effects models to associate changes in forest bird community structure with forest disturbance, latitude, and longitude in the conterminous United States for the years 1985 to 2006. We document a significant divergence from the baseline structure for all birds of similar migratory habit and nest location, and all forest birds as a group from 1985 to 2006. Unexpectedly, decreases in progressive similarity resulted from small changes in richness (<1 species per route for the 22-year study period) and modest losses in abundance (-28.7 - -10.2 individuals per route) that varied by migratory habit and nest location. Forest disturbance increased progressive similarity for Neotropical migrants, permanent residents, ground nesting, and cavity nesting species. We also documented highest progressive similarity in the eastern United States. Contemporary forest bird community structure is changing rapidly over a relatively short period of time (e.g., approximately 22 years). Forest disturbance and forest regeneration are primary factors associated with contemporary forest bird community structure, longitude and latitude are secondary factors, and forest loss is a tertiary factor. Importantly, these findings suggest some regions of the United States may already fall below the habitat amount threshold where fragmentation effects become important predictors of forest bird community structure.

Statistical and procedural issues in the use of heated taxidermic mounts

USGS Publications Warehouse

Bakken, G.S.; Kenow, K.P.; Korschgen, C.E.; Boysen, A.F.

2000-01-01

Studies using mounts have an inherently nested error structure; calibration and standardization should use the appropriate procedures and statistics. One example is that individual mount differences are nested within morphological factors related to species, age, or gender; without replication, mount differences may be confused with differences due to morphology. Also, the sensitivity of mounts to orientation to wind or sun is nested within mount; without replication, inadvertent variation in mount positioning may be confused with differences among mounts. Data on heat loss from a of 1-day-old mallard duckling mount are used to illustrate orientation sensitivity. (C) 2000 Elsevier Science Ltd. All rights reserved.

Modeling potential impacts of the Garrison Diversion Unit project on Sand Lake and Arrowwood National Wildlife Refuges: a feasibility analysis

USGS Publications Warehouse

Hamilton, David B.; Auble, Gregor T.; Farmer, Adrian H.; Roelle, James E.

1987-01-01

The Garrison Diversion Unit (GDU) of the Pick-Sloan Missouri Basin program was authorized in 1965, with the purpose of diverting Missouri River water to the James River for irrigation, municipal and industrial water supply, fish and wildlife habitat, recreation, and flood control. The project was reauthorized in 1986, with the specification that comprehensive studies be conducted to address a variety of issues. One of these ongoing studies addresses potential impacts of GDU construction and operation on lands of the National Wildlife Refuge (NWR) system, including Arrowwood and Sand Lake Refuges (the Refuges) on the James River. A number of concerns at these Refuges have been identified; the primary concerns addressed in this report include increased winter return flows, which would limit control of rough fish; increased turbidity during project construction, which would decrease production of sago pondweed; and increased water level fluctuations in the late spring and early summer, which would destroy the nests of some over-water nesting birds. The facilitated workshop described in this report was conducted February 18-20, 1987, under the joint sponsorship of the U.S. Bureau of Reclamation, the U.S. Fish and Wildlife Service, and the North Dakota Game and Fish Department. The primary objectives of the workshop were to evaluate the feasibility of using simulation modeling techniques to estimate GDU impacts on Arrowwood and Sand Lake Refuges and to suggest enhancements to the James River Refuge monitoring program. The workshop was structured around the formulation of four submodels: a Hydrology and Water Quality submodel to simulate changes in Refuge pool elevations, turnover rates, and water quality parameters (e.g., total dissolved solids, turbidity, dissolved oxygen, nutrients, water temperature, pesticides) due to GDU construction and operation; a Vegetation submodel to simulate concomitant changes in wetland communities (e.g., sago pondweed, wet meadows, deep and shallow marsh); a Fish submodel to estimate changes in abundance or biomass of rough fish (carp, buffalo) and sportfish (northern pike); and a Wildlife submodel to calculate indices of waterfowl abundance or habitat suitability (e.g., for mallards, western grebes, migrating diving ducks, white-faced ibis, egrets, over-water nesters). Submodels considered weekly to monthly changes in pools within a Refuge over a time horizon of 30-50 years. Based on workshop discussions and past experience with impact analysis modeling, a phased modeling approach was recommended for the James River Refuges analysis. The first phase would involve two modeling efforts. The existing Sand Lake hydrology model, and a similar one developed for Arrowwood NWR, would be validated and used to predict changes on pool elevations and winter inflows to each pool for a variety of GDU alternatives. Outputs from simulations would then be evaluated in terms of potential fish and wildlife impacts. For example, the models could generate indices comparing the magnitude and timing of winter inflows for pre- and postproject conditions; fisheries biologists could then use these indices to better quantify their concerns relative to potential changes in the frequency of rough-fish control. The other modeling effort in the first phase would involve developing a sago pondweed growth model to integrate Refuge monitoring data and existing literature and perhaps to address some questions concerning turbidity impacts. A second phase of simulation modeling would be undertaken only if the initial analyses of hydrologic outputs indicated significant potential problems and if monitoring and research projects had clarified some of the biological and physical processes that cannot be modeled reliably at the present time (e.g., resuspension of sediments by carp, immigration and winter mortality of fish, loss of waterfowl nests due to wave action). The second phase would attempt to develop an integrated impact assessment model. In order to address some of the biological and physical processes that presently are not well understood, a number of studies and enhancements to the Refuge monitoring program were suggested. The Hydrology and Water Quality workgroup recommended increasing turbidity and dissolved oxygen sampling, dropping expensive analysis of some trace elements, adding more pesticide analysis (including some biological monitoring), and developing better area-capacity data for the Sand Lake hydrology model. The Vegetation workgroup suggested expanding the number of monitoring stations, monitoring photosynthetically active radiation by depth, and modifying the biomass sampling procedure and schedule. Also suggested were additional analyses of existing Refuge monitoring data and additional field studies concerning sago growth under a variety of environmental conditions and effects of rough fish density on sago. A careful examination of Refuge narrative reports was recommended by the Fish workgroup to characterize conditions that led to various rates of winter-kill. Monitoring enhancement related to a better understanding of fish population dynamics included increasing dissolved oxygen monitoring, continuing present monitoring of fish movement upstream from Jamestown Reservoir into Arrowwood NWR, initiating similar efforts for upstream movement into Sand Lake NWR and downstream movements into both Refuges, and augmenting the present gillnetting program (or replacing it) with sampling for population and age/size structure estimates. The Wildlife workgroup suggested estimating the relative density of mallard nests in over-water and wet meadow nesting areas, estimating the number of western grebe nests lost due to wave action, delineating wet meadows on the Refuge vegetation maps, estimating annual tuber consumption by birds, and monitoring insect/macroinvertebrate abundance. The workgroup also suggested research studies to better understand the relationships between food supplies and the growth and survival of ducklings and young grebes. the workshop discussions also helped identify some suggestions for modifying project features that, if feasible from an engineering and operational standpoint, would reduce impacts on Refuge lands. These suggestions included: designing drains with control structures or small "reregulation" reservoirs to hold winter return flows that might adversely affect rough fish control, spreading construction activities over a number of years to reduce potential impacts of turbidity on sago pondweed in any single year, scheduling construction to occur after the spring sprouting and elongation growth stages to reduce impacts on sago pondweed, and installing "quick acting" control structures at Arrowwood NWR to reduce pool level fluctuations that might destroy nests of some over-water nesting waterfowl.

Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise.

PubMed

Hatfield, Jeff S; Reynolds, Michelle H; Seavy, Nathaniel E; Krause, Crystal M

2012-08-01

Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds. Conservation Biology ©2012 Society for Conservation Biology. No claim to original US government works.

Structure of northern spotted owl nest stands and their historical conditions on the eastern slope of the Pacific Northwest Cascades, USA.

Treesearch

Richard Everett; D. Schellhaas; D. Spurbeck; [and others].

1997-01-01

The northern spotted (Strix occidentalis caurina) uses a wide array of nesting habitat throughout its current range and successfully reproduces in a variety of stand types on the eastern slope of the Pacific Northwest Cascades. The species has the ability to utilize dynamic forest stands that continue to undergo significant changes in tree density...

Stigmergic construction and topochemical information shape ant nest architecture

PubMed Central

Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

2016-01-01

The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture. PMID:26787857

Stigmergic construction and topochemical information shape ant nest architecture.

PubMed

Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

2016-02-02

The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.

Mixed-stock analysis reveals the migrations of juvenile hawksbill turtles (Eretmochelys imbricata) in the Caribbean Sea.

PubMed

Bowen, B W; Grant, W S; Hillis-Starr, Z; Shaver, D J; Bjorndal, K A; Bolten, A B; Bass, A L

2007-01-01

Hawksbill turtles (Eretmochelys imbricata) migrate between nesting beaches and feeding habitats that are often associated with tropical reefs, but it is uncertain which nesting colonies supply which feeding habitats. To address this gap in hawksbill biology, we compile previously published and new mitochondrial DNA (mtDNA) haplotype data for 10 nesting colonies (N = 347) in the western Atlantic and compare these profiles to four feeding populations and four previously published feeding samples (N = 626). Nesting colonies differ significantly in mtDNA haplotype frequencies (Phi(ST) = 0.588, P < 0.001), corroborating earlier conclusions of nesting site fidelity and setting the stage for mixed-stock analysis. Feeding aggregations show lower but significant structure (Phi(ST) = 0.089, P < 0.001), indicating that foraging populations are not homogenous across the Caribbean Sea. Bayesian mixed-stock estimates of the origins of juveniles in foraging areas show a highly significant, but shallow, correlation with nesting population size (r = 0.378, P = 0.004), supporting the premise that larger rookeries contribute more juveniles to feeding areas. A significant correlation between the estimated contribution and geographical distance from nesting areas (r = -0.394, P = 0.003) demonstrates the influence of proximity on recruitment to feeding areas. The influence of oceanic currents is illustrated by pelagic stage juveniles stranded in Texas, which are assigned primarily (93%) to the upstream rookery in Yucatan. One juvenile had a haplotype previously identified only in the eastern Atlantic, invoking rare trans-oceanic migrations. The mixed-stock analysis demonstrates that harvests in feeding habitats will impact nesting colonies throughout the region, with the greatest detriment to nearby nesting populations.

High tides and rising seas: potential effects on estuarine waterbirds

USGS Publications Warehouse

Erwin, R.M.; Sanders, G.M.; Prosser, D.J.; Cahoon, D.R.; Greenberg, Russell; Maldonado, Jesus; Droege, Sam; McDonald, M.V.

2006-01-01

Coastal waterbirds are vulnerable to water-level changes especially under predictions of accelerating sea-level rise and increased storm frequency in the next century. Tidal and wind-driven fluctuations in water levels affecting marshes, their invertebrate communities, and their dependent waterbirds are manifested in daily, monthly, seasonal, annual, and supra-annual (e.g., decadal or 18.6-yr) periodicities. Superimposed on these cyclic patterns is a long-term (50?80 yr) increase in relative sea-level rise that varies from about 2?4 + mm/yr along the Atlantic coastline. At five study sites selected on marsh islands from Cape Cod, Massachusetts to coastal Virginia, we monitored marsh elevation changes and flooding, tide variations over time, and waterbird use. We found from longterm marsh core data that marsh elevations at three of five sites may not be sufficient to maintain pace with current sea-level rise. Results of the short-term (3?4 yr) measures using surface elevation tables suggest a more dramatic difference, with marsh elevation change at four of five sites falling below relative sea-level rise. In addition, we have found a significant increase (in three of four cases) in the rate of surface marsh flooding in New Jersey and Virginia over the past 70?80 yr during May?July when waterbirds are nesting on or near the marsh surface. Short-term, immediate effects of flooding will jeopardize annual fecundity of many species of concern to federal and state agencies, most notably American Black Duck (Anas rubripes), Nelson?s Sharp-tailed Sparrow (Ammodramus nelsoni), Saltmarsh Sharp-tailed Sparrow (A. caudacutus), Seaside Sparrow (A. maritima), Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens), Black Rail (Laterallus jamaicensis), Forster?s Tern (Sterna forsteri), Gull-billed Tern (S. nilotica), Black Skimmer (Rynchops niger), and American Oystercatcher (Haemotopus palliatus). Forster?s Terns are probably most at risk given the large proportion of their breeding range in the mid-Atlantic and their saltmarsh specialization. At a scale of 1?2 decades, vegetation changes (saltmeadow cordgrass [Spartina patens] and salt grass [Distichlis spicata] converting to smooth cordgrass [Spartina alternifl ora]), interior pond expansion and erosion of marshes will reduce nesting habitat for many of these species, but may enhance feeding habitat of migrant shorebirds and/or migrant or wintering waterfowl. At scales of 50?100 yr, reversion of marsh island complexes to open water may enhance populations of open-bay waterfowl, e.g., Bufflehead (Bucephala albeola) and Canvasback (Aythya valisneria), but reduce nesting habitats dramatically for the above named marsh-nesting species, may reduce estuarine productivity by loss of the detrital food web and nursery habitat for fish and invertebrates, and cause redistribution of waterfowl, shorebirds, and other species. Such scenarios are more likely to occur in the mid- and north Atlantic regions since these estuaries are lower in sediment delivery on average than those in the Southeast. A simple hypothetical example from New Jersey is presented where waterbirds are forced to shift from submerged natural marshes to nearby impoundments, resulting in roughly a 10-fold increase in density. Whether prey fauna are sufficiently abundant to support this level of increase remains an open question, but extreme densities in confined habitats would exacerbate competition, increase disease risk, and possibly increase predation.

The differential emission measure of nested hot and cool magnetic loops

NASA Technical Reports Server (NTRS)

Van Hoven, G.; Mok, Y.

1993-01-01

The detailed thermal structure of the magnetized solar transition region, as measured by its differential emission measure (DEM(T)), is poorly known. Building on the fact that the solar surface is strongly magnetized and thereby structured, proposals have been made that envision a significant lower-temperature contribution to the energy balance from (ion) heat flux across an arcade of different temperature loops. In this paper, we describe a self-consistent 2D MHD simulation, which includes the full thermal effects of parallel stability and anisotropic conduction, of a nested-loop model of the thermal and magnetic structure of the transition region. We then demonstrate that the predicted DEM agrees with observations in the conceptually elusive T less than 10 exp 5 K regime.

The interdigital brace and other grips for termite nest perforation by chimpanzees of the Goualougo Triangle, Republic of Congo.

PubMed

Lesnik, Julie J; Sanz, Crickette M; Morgan, David B

2015-06-01

Studies of chimpanzee termite foraging enlighten our understanding of early hominin tool use not only by modeling the cognitive ability of our ancestors but also by emphasizing the possible role of social insects in the hominin diet. The chimpanzees of the Goualougo Triangle are known to have one of the largest and most complex tool repertoires reported for wild chimpanzees. One tool set habitually used by this population includes a perforating tool to penetrate the hard outer crust of elevated termite nests before fishing for termite prey with an herbaceous stem. Here, we report the variation present in the grips used on the perforating tool. Our analysis of video recordings of chimpanzee visitation to termite nests over a 3-year period shows that these chimpanzees use a variety of grips to navigate the challenges encountered in opening a termite nest. For situations in which the soil is most hardened, perforating requires force and a power grip is often used. When the soil in the passageway is loose, precision grips are suitable for the task. One of the preferred grips reported here is an interdigital brace, which has previously been described in studies of how some people hold a pencil. In this study, for the first time, the interdigital brace has been thoroughly described for chimpanzees. The various strategies and grips used during perforation emphasize the importance of termites as a nutritional resource that should be considered more strongly as a food used by early hominins. © 2015 Wiley Periodicals, Inc.

Comparison of breaking strength and shell thickness as evaluators of white-faced ibis eggshell quality

USGS Publications Warehouse

Henny, C.J.; Bennett, J.K.

1990-01-01

Data from a 1986 field study of white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada, were used to compare the utility of eggshell strength measurement and eggshell thickness as indicators of eggshell quality. The ibis population had a history of reproductive failure correlated with elevated egg concentrations of p,p`DDE, hereafter referred to as DDE. Eggs from 80 nests (one egg/nest) were tested for shell strength and thickness. Egg contents were analyzed for organochlorines, mercury and selenium; productivity at each nest (minus one egg) was monitored in the field. DDE-DDT concentrations in the eggs ranged from none detected (less than 0.1) to 29 ppm (wet weight). Shell thickness and shell strength were both negatively correlated with DDE (0.60, 0.61, respectively), but shell strength deteriorated at a faster rate than shell thickness. Scanning electron micrographs indicated the deterioration in strength was related to changes in ultrastructure as well as to decreased thickness. Fourteen eggs with less than 0.40 ppm DDE were used to exemplify normal control eggs. Of the eggs with higher concentrations of DDE (i.e., greater than or equal to 0.40 ppm), 11 of 66 were thinner (greater than 2 SD below 'control' mean) than normal, 11 of 59 were weaker than normal and 7 eggs were cracked so their strength could not be tested, although thickness was measured. Therefore, 17% of the eggs with greater than or equal to 0.40 ppm DDE were thinner than normal and 27% were either weaker than normal or cracked. Further, six eggs (four with greater than or equal to 15 ppm DDE) did not have abnormally thin shells, but did have abnormally weak shells. Nests with abnormal test eggs (thinner, weaker or cracked) produced fewer young than nests with normal eggs. Use of the shell strength parameter provides additional information for better evaluations of reproductive problems. The potential utility of monitoring eggshell quality goes beyond evaluating effects of organochlorines since recent work indicates that other environmental hazards can affect shell quality.

Compilation of 1990 annual reports of the Navy ELF communications system ecological monitoring program. Volume 2: Tabs C thru F

NASA Astrophysics Data System (ADS)

Zapotosky, J. E.

1991-08-01

This portion of the report includes monitoring of and data for arthropoda and earthworms; pollinating insects; and small mammals and nesting birds. During the 1990 growing season the ELF antenna was operated more frequently than in prior years. This provides 2 years of intermittent ELF exposure for the biological systems to react to the radiation, one year of very limited exposure and greater exposure in 1990. Arthropod and earthworm sampling was conducted at intervals of two weeks from early May to late October. High voltage transmission lines and magnetic fields have been shown to affect honeybee reproduction, survival, orientation, and nest structure. ELF EM fields could have similar effects on native megachild bees. Changes in cell length, number of cells per nest, number of leaver per cell, orientation of nest entrances, and time to collect a round leaf pierce to cap a cell were monitored. We have not detected significant changes that could be attributed to ELF EM fields. Small mammal and nesting bird biological studies in the western Upper Peninsula of Michigan for the year 1990 are reported.

The evolution of eggshell cuticle in relation to nesting ecology

PubMed Central

Hauber, Mark E.

2016-01-01

Avian eggs are at risk of microbial infection prior to and during incubation. A large number of defence mechanisms have evolved in response to the severe costs imposed by these infections. The eggshell's cuticle is an important component of antimicrobial defence, and its role in preventing contamination by microorganisms in domestic chickens is well known. Nanometer-scale cuticular spheres that reduce microbial attachment and penetration have recently been identified on eggs of several wild avian species. However, whether these spheres have evolved specifically for antimicrobial defence is unknown. Here, we use comparative data on eggshell cuticular structure and nesting ecology to test the hypothesis that birds nesting in habitats with higher risk of infection (e.g. wetter and warmer) are more likely to evolve cuticular nanospheres on their eggshells than those nesting in less risky habitats. We found that nanostructuring, present in 54 of 296 analysed species, is the ancestral condition of avian eggshells and has been retained more often in taxa that nest in humid infection-prone environments, suggesting that they serve critical roles in antimicrobial egg defence. PMID:27488648

The evolution of eggshell cuticle in relation to nesting ecology.

PubMed

D'Alba, Liliana; Maia, Rafael; Hauber, Mark E; Shawkey, Matthew D

2016-08-17

Avian eggs are at risk of microbial infection prior to and during incubation. A large number of defence mechanisms have evolved in response to the severe costs imposed by these infections. The eggshell's cuticle is an important component of antimicrobial defence, and its role in preventing contamination by microorganisms in domestic chickens is well known. Nanometer-scale cuticular spheres that reduce microbial attachment and penetration have recently been identified on eggs of several wild avian species. However, whether these spheres have evolved specifically for antimicrobial defence is unknown. Here, we use comparative data on eggshell cuticular structure and nesting ecology to test the hypothesis that birds nesting in habitats with higher risk of infection (e.g. wetter and warmer) are more likely to evolve cuticular nanospheres on their eggshells than those nesting in less risky habitats. We found that nanostructuring, present in 54 of 296 analysed species, is the ancestral condition of avian eggshells and has been retained more often in taxa that nest in humid infection-prone environments, suggesting that they serve critical roles in antimicrobial egg defence. © 2016 The Author(s).

Cloud Intrusion Detection and Repair (CIDAR)

DTIC Science & Technology

2016-02-01

form for VLC , Swftools-png2swf, Swftools-jpeg2swf, Dillo and GIMP. The superscript indicates the bit width of each expression atom. “sext(v, w... challenges in input rectification is the need to deal with nested fields. In general, input formats are in tree structures containing arbitrarily...length indicator constraints is challeng - ing, because of the presence of nested fields in hierarchical input format. For example, an integer field may

Wiesner Nevus of the Eyelid.

PubMed

Somogyi, Marie; Lyons, Lance J; Durairaj, Vikram

A healthy 31-year-old female presented with an elevated vascular lesion on the right lower eyelid margin. Histology results from excisional biopsy demonstrated a range of intradermally nested atypical melanocytes with negative staining for BRCA1-associated protein 1, confirming the diagnosis of Wiesner nevus. Wiesner nevi may be a cutaneous hallmark of the BRCA1-associated protein 1-associated cancer susceptibility syndrome, and to our knowledge, this is the first report of such a lesion presenting anywhere on the ocular adnexa.

Communities of Social Bees (Apidae: Meliponini) in Trap-Nests: the Spatial Dynamics of Reproduction in an Area of Atlantic Forest.

PubMed

Silva, M D; Ramalho, M; Monteiro, D

2014-08-01

As most stingless bee species depend on preexisting cavities, principally tree hollows, nesting site availability may represent an important restriction in the structuring of their forest communities. The present study examined the spatial dynamics of stingless bee communities in an area of Atlantic Forest by evaluating their swarming to trap-nests. The field work was performed in the Michelin Ecological Reserve (MER) on the southeastern coast of the state of Bahia, Brazil. Seven hundred and twenty trap-nests were distributed within two forest habitats in advanced and initial stages of regeneration. The trap-nests were monitored between September 2009 and March 2011. Twenty-five trap-nests were occupied by five bee species, resulting in a capture ratio of 0.035 swarms/trap (approximately 0.14 swarms/ha), corresponding to 10 swarms/year (0.056 swarms/ha/year). According to previous study at MER, the most abundant species in natural nests were also the most common in trap-nests in the two forest habitats examined, with the exception of Melipona scutellaris Latreille. Swarms of higher numbers of species were captured in initial regeneration stage forests than in advanced regeneration stage areas, and differences in species compositions were significant between both habitats (p = 0.03); these apparent differences were not consistent, however, when considering richness (p = 0.14) and total abundance (p = 0.08). The present study suggests the existence of a minimum cavity size threshold of approximately 1 L for most local species of stingless bees and sustains the hypothesis of a mass effect of Tetragonisca angustula Latreille populations from surrounding disturbed habitats on the MER forest community in terms of propagule (swarm) pressure. Examining swarm densities with trap-nests can be a promising technique for comparative analyses of the carrying capacities of forest habitats for stingless bee colonies, as long as size thresholds of cavities for nesting are taken into consideration.

Impacts of Water Levels on Breeding Canada Geese and Methods for Mitigation and Management in the Southern Flathead Valley, Montana, 1983-1987 Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackey, Dennis L.; Gregory, Shari K.; Matthews, William C. Jr.

Kerr Hydroelectric Dam is located at the south end of Flathead Lake, controls water levels on the lake and the Flathead River below the dam, and is currently operated as a load control facility. Current operation of Kerr Dam creates the greatest yearly water level fluctuations on both the lake and river during the Canada goose (Branta canadensis moffitti) brood and nesting period. Data collected from 1980-1982 indicated that goose nest numbers on the river were lower than during the 1950's, and that brood habitat on the lake may be limiting the goose population there. Our study was conducted frommore » 1983-1987 to determine the effects of Kerr Dam operation on Canada goose populations and habitat on the south half of Flathead Lake and the Flathead River, and to formulate management and mitigation recommendations. Nesting geese on the river appeared to be negatively affected by a lack of nest sites free from predators, and responded to available artificial nest structures with an increase in nest numbers and nesting success. Under current dam operation, river channel depths and widths do not discourage access to nesting islands by mammalian predators during some years and high predation on ground nests occurs. Intensively used brood areas on the lake and river were identified and described. Brood habitat on the lake was lower in quality and quantity than on the river due to dam operations. Gosling mortality on the lake was high, almost 2 times higher than on the river. Lake broods expended more energy obtaining food than river broods. Losses of brood habitat in the form of wet meadow marshes were documented and mitigation options developed. Management/mitigation alternatives and monitoring methods for nesting and brooding geese were identified.« less

Interphyletic relationships in the use of nesting cavities: mutualism, competition and amensalism among hymenopterans and vertebrates

NASA Astrophysics Data System (ADS)

Veiga, José P.; Wamiti, Wanyoike; Polo, Vicente; Muchai, Muchane

2013-09-01

Although competition is usually assumed to be the most common interaction between closely related organisms that share limiting resources, the relationships linking distant taxa that use the same nesting sites are poorly understood. In the present study, we examine the interactions among social hymenopterans (honeybees and wasps) and vertebrates in tropical ecosystems of East Africa. By analysing the preferences of these three groups for nest boxes that were empty or previously occupied by a different taxon, we try to establish whether the relationships among them are commensal, mutualistic, competitive or amensal. Vertebrates and honeybees selected nest boxes that had previously been occupied by the other, which suggests that each obtains some benefit from the other. This relationship can be considered mutualistic, although a mutual preference for each others' nests does not exclude a competitive interaction. Vertebrates and wasps preferred nest boxes not previously occupied by the other, which suggests that they compete for tree cavities. Finally, wasps seemed to completely refuse cavities previously used by honeybees, while the bees occupied cavities regardless of whether they had been previously used by wasps, an apparently amensal relationship. These results indicate that the interdependence between distantly related taxa is stronger and more complex than previously described, which may have important implications for population dynamics and community structure.

Real estate ads in Emei music frog vocalizations: female preference for calls emanating from burrows.

PubMed

Cui, Jianguo; Tang, Yezhong; Narins, Peter M

2012-06-23

During female mate choice, both the male's phenotype and resources (e.g. his nest) contribute to the chooser's fitness. Animals other than humans are not known to advertise resource characteristics to potential mates through vocal communication; although in some species of anurans and birds, females do evaluate male qualities through vocal communication. Here, we demonstrate that calls of the male Emei music frog (Babina dauchina), vocalizing from male-built nests, reflect nest structure information that can be recognized by females. Inside-nest calls consisted of notes with energy concentrated at lower frequency ranges and longer note durations when compared with outside-nest calls. Centre frequencies and note durations of the inside calls positively correlate with the area of the burrow entrance and the depth of the burrow, respectively. When given a choice between outside and inside calls played back alternately, more than 70 per cent of the females (33/47) chose inside calls. These results demonstrate that males of this species faithfully advertise whether or not they possess a nest to potential mates by vocal communication, which probably facilitates optimal mate selection by females. These results revealed a novel function of advertisement calls, which is consistent with the wide variation in both call complexity and social behaviour within amphibians.

Fine-scale thermal adaptation in a green turtle nesting population

PubMed Central

Weber, Sam B.; Broderick, Annette C.; Groothuis, Ton G. G.; Ellick, Jacqui; Godley, Brendan J.; Blount, Jonathan D.

2012-01-01

The effect of climate warming on the reproductive success of ectothermic animals is currently a subject of major conservation concern. However, for many threatened species, we still know surprisingly little about the extent of naturally occurring adaptive variation in heat-tolerance. Here, we show that the thermal tolerances of green turtle (Chelonia mydas) embryos in a single, island-breeding population have diverged in response to the contrasting incubation temperatures of nesting beaches just a few kilometres apart. In natural nests and in a common-garden rearing experiment, the offspring of females nesting on a naturally hot (black sand) beach survived better and grew larger at hot incubation temperatures compared with the offspring of females nesting on a cooler (pale sand) beach nearby. These differences were owing to shallower thermal reaction norms in the hot beach population, rather than shifts in thermal optima, and could not be explained by egg-mediated maternal effects. Our results suggest that marine turtle nesting behaviour can drive adaptive differentiation at remarkably fine spatial scales, and have important implications for how we define conservation units for protection. In particular, previous studies may have underestimated the extent of adaptive structuring in marine turtle populations that may significantly affect their capacity to respond to environmental change. PMID:21937495

Nest Sanitation as the Evolutionary Background for Egg Ejection Behaviour and the Role of Motivation for Object Removal

PubMed Central

Poláček, Miroslav; Griggio, Matteo; Bartíková, Michaela; Hoi, Herbert

2013-01-01

Higher interclutch colour variation can evolve under the pressure of brood parasitism to increase the detection of parasitic eggs. Nest sanitation could be a prerequisite for the evolution of anti-parasite defence in terms of egg ejection. In this respect, we used nest sanitation behaviour as a tool to identify: i) motivation and its underlying function and, ii) which features provoke ejection behaviour. Therefore, we experimentally tested whether size, colour or shape may influence ejection behaviour using artificial flat objects. We found a high interclutch variation in egg colouration and egg size in our tree sparrow (Passer montanus) population. Using colour and size we were in fact able to predict clutch affiliation for each egg. Our experiments further revealed the existence of direct anti-parasite behaviours and birds are able to recognise conspecific eggs, since only experimentally-deposited eggs have been removed. Moreover, experiments with different objects revealed that the motivation of tree sparrows to remove experimental objects from their nests was highest during egg laying for objects of varying size, most likely because of parasitism risk at this breeding stage. In contrary, motivation to remove white objects and objects with edges was higher during incubation stage as behavioural patterns connected to hatching started to emerge. The fact that rejection rate of our flat objects was higher than real egg ejection, suggests that egg ejection in tree sparrows and probably more general in small passerines, to be limited by elevated costs to eject eggs with their beaks. The presence of anti-parasite behaviour supports our suggestion that brood parasitism causes variation in egg features, as we have found that tree sparrows can recognise and reject conspecific eggs in their clutch. In conclusion, in tree sparrows it seems that nest sanitation plays a key role in the evolution of the removal of parasitic eggs. PMID:24223165

Nest sanitation as the evolutionary background for egg ejection behaviour and the role of motivation for object removal.

PubMed

Poláček, Miroslav; Griggio, Matteo; Bartíková, Michaela; Hoi, Herbert

2013-01-01

Higher interclutch colour variation can evolve under the pressure of brood parasitism to increase the detection of parasitic eggs. Nest sanitation could be a prerequisite for the evolution of anti-parasite defence in terms of egg ejection. In this respect, we used nest sanitation behaviour as a tool to identify: i) motivation and its underlying function and, ii) which features provoke ejection behaviour. Therefore, we experimentally tested whether size, colour or shape may influence ejection behaviour using artificial flat objects. We found a high interclutch variation in egg colouration and egg size in our tree sparrow (Passer montanus) population. Using colour and size we were in fact able to predict clutch affiliation for each egg. Our experiments further revealed the existence of direct anti-parasite behaviours and birds are able to recognise conspecific eggs, since only experimentally-deposited eggs have been removed. Moreover, experiments with different objects revealed that the motivation of tree sparrows to remove experimental objects from their nests was highest during egg laying for objects of varying size, most likely because of parasitism risk at this breeding stage. In contrary, motivation to remove white objects and objects with edges was higher during incubation stage as behavioural patterns connected to hatching started to emerge. The fact that rejection rate of our flat objects was higher than real egg ejection, suggests that egg ejection in tree sparrows and probably more general in small passerines, to be limited by elevated costs to eject eggs with their beaks. The presence of anti-parasite behaviour supports our suggestion that brood parasitism causes variation in egg features, as we have found that tree sparrows can recognise and reject conspecific eggs in their clutch. In conclusion, in tree sparrows it seems that nest sanitation plays a key role in the evolution of the removal of parasitic eggs.

Characterisation of microbial communities in Chinese liquor fermentation starters Daqu using nested PCR-DGGE.

PubMed

Zhang, Liqiang; Wu, Chongde; Ding, Xiaofei; Zheng, Jia; Zhou, Rongqing

2014-12-01

In this study, characterises of the microbial community structures of three typical Chinese liquor Daqu, as well as different kinds of light flavour Daqu were investigated using nested PCR-denaturing gradient gel electrophoresis (DGGE). The results showed that microbial diversity was considerably different, and the microfloral compositions were highly variable among various Daqu. Lactic acid bacteria, which accounted for 30.95 % of all identified bacteria, were dominant in all Daqu samples, whereas Bacillus species were also predominant in the Luzhou (14.8 %) and Langjiu Daqu (18.2 %). Citrobacter and Burkholderia were first identified in light flavour Daqu. Aspergillus was the dominant moulds, and the non-Saccharomyces yeast species, Saccharomycopsis fibuligera, Wallemia sebi, Wallemia muriae, and Pichia subpelliculosa, were the dominant yeasts. Rasamsonia, Galactomyces, Geotrichum and Wallemia were first identified using nested PCR-DGGE. Cluster analysis indicated that the microbial community structures of different Daqu samples exhibited some differences. These may be ascribed to the different peak production temperatures, raw material constituents and microhabitats around the liquor enterprises. The current study provides insights into the microbial community structures of three typical Daqu samples, and may facilitate the development of starter cultures for manufacturing Chinese liquor.

Ecology and habitat of breeding Northern Goshawks in the inland Pacific Northwest: A summary of research in the 1990s

USGS Publications Warehouse

DeStefano, S.; McGrath, M.T.; Daw, S.K.; Desimone, S.M.

2006-01-01

During the 1990s, we conducted research on the distribution, productivity, and habitat relationships of Northern Goshawks (Accipiter gentilis) in eastern Oregon and Washington. Our research was initiated primarily in response to concerns raised about the status of Northern Goshawks in the western US, and coincided with early attempts to list the species as threatened or endangered under the Endangered Species Act and the publication of management guidelines for goshawks in the southwestern US. To develop baseline information on the status, distribution, and habitat relationships of goshawks in eastside forests (i.e., east of the Cascade Mountain Range) in the Pacific Northwest, we established study areas on three national forests in eastern Oregon in 1992, adding a fourth study area in central Washington in 1994. We focused on the breeding season and nesting habitat because of its primary importance to goshawk ecology and the logistical feasibility of finding nests. Density of breeding pairs ranged from 0.03-0.09/100 ha, and annual productivity ranged from 0.3-2.2 young fledged/nest. Goshawks selected forest stands with trees of larger diameter and greater canopy closure for nesting than available in the landscape. Occasionally nests could be found in large trees in open-canopied stands. As distance increased from the nest site, forest type and structure became more heterogeneous and the prevalence of older-seral-stage forest declined. Dry or wet openings were present in most territories, often within close proximity to nest stands. Goshawks ate a variety of mammalian and avian prey. Mammal species made up a larger portion of prey biomass on two of the national forests, but avian species appeared to be more prevalent in the diet of goshawks in the most northern study area. We recommend that the existing management guidelines for goshawks in the Southwest form a basis for management in the inland Pacific Northwest, particularly with regard to nested spatial concepts, emphasis on management of prey, and the use of silviculture to promote the development and replacement of old growth or late-seral-stage forest. Our research and management recommendations can be used in concert with the Southwestern management guidelines to establish a mix of vegetation structural stages to support goshawk populations, their prey, and other forest wildlife species specifically for the inland Pacific Northwest.

The numerics of hydrostatic structured-grid coastal ocean models: State of the art and future perspectives

NASA Astrophysics Data System (ADS)

Klingbeil, Knut; Lemarié, Florian; Debreu, Laurent; Burchard, Hans

2018-05-01

The state of the art of the numerics of hydrostatic structured-grid coastal ocean models is reviewed here. First, some fundamental differences in the hydrodynamics of the coastal ocean, such as the large surface elevation variation compared to the mean water depth, are contrasted against large scale ocean dynamics. Then the hydrodynamic equations as they are used in coastal ocean models as well as in large scale ocean models are presented, including parameterisations for turbulent transports. As steps towards discretisation, coordinate transformations and spatial discretisations based on a finite-volume approach are discussed with focus on the specific requirements for coastal ocean models. As in large scale ocean models, splitting of internal and external modes is essential also for coastal ocean models, but specific care is needed when drying & flooding of intertidal flats is included. As one obvious characteristic of coastal ocean models, open boundaries occur and need to be treated in a way that correct model forcing from outside is transmitted to the model domain without reflecting waves from the inside. Here, also new developments in two-way nesting are presented. Single processes such as internal inertia-gravity waves, advection and turbulence closure models are discussed with focus on the coastal scales. Some overview on existing hydrostatic structured-grid coastal ocean models is given, including their extensions towards non-hydrostatic models. Finally, an outlook on future perspectives is made.

Origin of mounds in the Pantanal wetlands: An integrated approach between geomorphology, pedogenesis, ecology and soil micromorphology.

PubMed

de Oliveira Junior, Jairo Calderari; Beirigo, Raphael Moreira; Chiapini, Mariane; do Nascimento, Alexandre Ferreira; Couto, Eduardo Guimarães; Vidal-Torrado, Pablo

2017-01-01

Vegetated mounds are an important geomorphological feature of the Pantanal, where the influence of floods dictates not only hydropedological processes, but also the distribution and ecology of the flora and fauna. This work aimed to identify factors and processes that influence the formation and spatial distribution of the mounds, which are commonly associated with termite activity. In order to characterize pedological processes, macro and micro morphological descriptions, satellite image interpretation, dating of the sandy sedimentary material using OSL and carbon dating using 14C AMS were carried out. This dating of the materials indicates that the sediments in which the soils were formed were deposited during the Pleistocene, while the carbonates are from the Holocene. The basin-like format of the laminar structures suggests that part of the more clayey material was deposited in lacustrine environments. The more humid climate in the Holocene intensified argilluviation, which at an advanced stage, led to a more pronounced textural gradient, reducing drainage and leading to ferrolysis and thickening of the E horizon. Besides pedogenic processes, more erosive flooding during the Holocene began reducing and rounding the landscape's more elevated structures (paleolevees). In the final stage, these structures were occupied by termites to shelter from flooding. Thereafter, the bio-cementation action of the termite nests has increased the resistance of the vegetated mounds to processes of erosion.

Origin of mounds in the Pantanal wetlands: An integrated approach between geomorphology, pedogenesis, ecology and soil micromorphology

PubMed Central

de Oliveira Junior, Jairo Calderari; Beirigo, Raphael Moreira; Chiapini, Mariane; do Nascimento, Alexandre Ferreira; Couto, Eduardo Guimarães

2017-01-01

Vegetated mounds are an important geomorphological feature of the Pantanal, where the influence of floods dictates not only hydropedological processes, but also the distribution and ecology of the flora and fauna. This work aimed to identify factors and processes that influence the formation and spatial distribution of the mounds, which are commonly associated with termite activity. In order to characterize pedological processes, macro and micro morphological descriptions, satellite image interpretation, dating of the sandy sedimentary material using OSL and carbon dating using 14C AMS were carried out. This dating of the materials indicates that the sediments in which the soils were formed were deposited during the Pleistocene, while the carbonates are from the Holocene. The basin-like format of the laminar structures suggests that part of the more clayey material was deposited in lacustrine environments. The more humid climate in the Holocene intensified argilluviation, which at an advanced stage, led to a more pronounced textural gradient, reducing drainage and leading to ferrolysis and thickening of the E horizon. Besides pedogenic processes, more erosive flooding during the Holocene began reducing and rounding the landscape’s more elevated structures (paleolevees). In the final stage, these structures were occupied by termites to shelter from flooding. Thereafter, the bio-cementation action of the termite nests has increased the resistance of the vegetated mounds to processes of erosion. PMID:28700595

Reproductive plasticity and landscape heterogeneity benefit a ground-nesting bird in a fire-prone ecosystem.

PubMed

Carroll, J Matthew; Hovick, Torre J; Davis, Craig A; Elmore, Robert Dwayne; Fuhlendorf, Samuel D

2017-10-01

Disturbance is critical for the conservation of rangeland ecosystems worldwide and many of these systems are fire dependent. Although it is well established that restoring fire as an ecological process can lead to increased biodiversity in grasslands and shrublands, the underlying mechanisms driving community patterns are poorly understood for fauna in fire-prone landscapes. Much of this uncertainty stems from the paucity of studies that examine the effects of fire at scales relevant to organism life histories. We assessed the response of a non-migratory ground-dwelling bird to disturbance (i.e., prescribed fire) and environmental stochasticity over the course of a 4-yr period, which spanned years of historic drought and record rainfall. Specifically, we investigated the nesting ecology of Northern Bobwhite (Colinus virginianus; hereafter Bobwhite) to illuminate possible avenues by which individuals respond to dynamic landscape patterns during a critical reproductive stage (i.e., nesting) in a mixed-grass shrubland in western Oklahoma, USA. We found that Bobwhites exhibited extreme plasticity in nest substrate use among time since fire categories (TSF) and subsequently maintained high nest survival (e.g., 57-70%). Bobwhites were opportunistic in nest substrate use among TSF categories (i.e., 72% of nest sites in shrubs in 0-12 months post fire compared to 71% in herbaceous vegetation in >36 months post fire), yet nesting decisions were first filtered by similar structural components (i.e., vertical and horizontal cover) within the vicinity of nest sites regardless of TSF category. Despite being a non-migratory and comparatively less mobile ground-nesting bird species, Bobwhites adjusted to dynamic vegetation mosaics on a fire-prone landscape under stochastic climatic conditions that culminated in stable and high nest survival. Broadly, our findings provide a unique depiction of organism response strategies to fire at scales relevant to a critical life-stage, a topic that has been previously understudied and poorly understood. We also demonstrate how doing so can better inform conservation practices aimed at restoring fire regimes on grassland and shrubland landscapes. © 2017 by the Ecological Society of America.

[Recent fauna of ground-nesting birds in Transvolga steppes and its dynamics in the 20th century].

PubMed

Oparin, M L

2008-01-01

It is shown that the structure of the ground-nesting bird fauna in Transvolga steppes has changed during the 20th century. The complex of lark species characteristic of true and dry steppe has disappeared because of climate change and impact of economic activity (the establishment of windbreak and roadside forest strips), which has provided for a sharp increase in the abundance of corvid birds.

Foraging and nesting habitat of breeding male northern goshawks in the laurentian mixed forest province, Minnesota

USGS Publications Warehouse

Boal, C.W.; Andersen, D.E.; Kennedy, P.L.

2005-01-01

We used radiotelemetry to examine foraging habitat preferences of 17 breeding, male northern goshawks (Accipiter gentilis) in Minnesota from 1998-2000. We assessed habitat preference using radio relocation points and 50-m radius buffers of radio relocation points. Our data suggested that foraging male goshawks used early-successional upland conifer stands (???25 yrs old), early-successional upland deciduous stands (???50 yrs old), late-successional upland conifer stands (???50 yrs old), and late-successional upland deciduous stands (???50 yrs old) more frequently than expected based on the abundance of these vegetation types in the landscape. The 2 most available stand types, early-successional upland deciduous (<25 yrs old) and all ages of late-successional lowland conifer stands, were used less than expected by foraging goshawks. Late-successional lowland deciduous stands (???50 yrs old) were used in proportion to availability. Although analysis of relocation points suggested early-successional upland deciduous stands (25-49 yrs old) and late-successional upland conifer stands (???50 yrs old) were used in proportion to availability, analysis of buffers around relocation points indicated that these stand types were also used more than expected by foraging goshawks. Regardless of vegetation community type, stands used by goshawks were structurally similar with high canopy and understory stem densities, high canopy closure, substantial shrub cover, and large amounts of woody debris. Nest stands consisted of taller and larger diameter canopy trees and fewer understory trees than foraging stands, but stands were otherwise similar in structural features, suggesting goshawks used similar stands for nesting and foraging but that they tended to select the most mature stands for nesting. A commonality among nesting and foraging stands was the presence of open spaces between the canopy and understory foliage, and between understory and shrub layer foliage. In our study area, these spaces may have served as relatively unobstructed flight paths where foraging and nesting stands possessed stem densities at the upper end of that reported for goshawk habitat.

Age-related differences in nest defense in common terns: Relationship to other life-history parameters.

PubMed

Pearson, Jennifer; Nisbet, Ian C T; Ottinger, Mary Ann

2005-12-01

The Common Tern (Sterno hirundo) is a long-lived colonial nesting seabird. Previous studies have shown that chick growth and fledging success vary with age of the parental pair and with laying date, with older parents and those nesting earlier being more successful. This study investigated the dependence of breeding performance and one aspect of behavior, defense against conspecifics, on age and laying date. Nest defense behavior was evaluated by recording individual responses to a mirror placed 20 cm from the nest, simulating an unfamiliar intruder within the territory. Most study birds were of known age (3-21 years) from banding as chicks; they were divided into three groups: ≥12, 8-11 and ≤seven years. Responses to the mirror were examined during incubation and at the time of hatching. Older birds nested earlier than younger birds. Chicks reared by older parents gained mass more quickly and survived better than chicks of younger parents. Using a composite score reflecting both the intensity and duration of aggressive responses to the mirror, older birds responded more strongly than younger birds during incubation, but responses were similar at the time of hatching. Older birds reduced their aggressive responses between incubation and hatching, while younger birds increased their responses. We suggest that this contributes to the greater success of older birds, because younger birds expend more time and energy on territorial defense at a time when they need to feed chicks. Our findings are consistent with previous studies and show that Common Tern colonies are finely structured by age and laying date; older and earlier-nesting birds are superior to younger and later birds on several measures of performance. This study suggests that finely-tuned nest defense behavior is one component of the superior performance of old birds.

Crucial nesting habitat for gunnison sage-grouse: A spatially explicit hierarchical approach

USGS Publications Warehouse

Aldridge, Cameron L.; Saher, D.J.; Childers, T.M.; Stahlnecker, K.E.; Bowen, Z.H.

2012-01-01

Gunnison sage-grouse (Centrocercus minimus) is a species of special concern and is currently considered a candidate species under Endangered Species Act. Careful management is therefore required to ensure that suitable habitat is maintained, particularly because much of the species' current distribution is faced with exurban development pressures. We assessed hierarchical nest site selection patterns of Gunnison sage-grouse inhabiting the western portion of the Gunnison Basin, Colorado, USA, at multiple spatial scales, using logistic regression-based resource selection functions. Models were selected using Akaike Information Criterion corrected for small sample sizes (AIC c) and predictive surfaces were generated using model averaged relative probabilities. Landscape-scale factors that had the most influence on nest site selection included the proportion of sagebrush cover >5%, mean productivity, and density of 2 wheel-drive roads. The landscape-scale predictive surface captured 97% of known Gunnison sage-grouse nests within the top 5 of 10 prediction bins, implicating 57% of the basin as crucial nesting habitat. Crucial habitat identified by the landscape model was used to define the extent for patch-scale modeling efforts. Patch-scale variables that had the greatest influence on nest site selection were the proportion of big sagebrush cover >10%, distance to residential development, distance to high volume paved roads, and mean productivity. This model accurately predicted independent nest locations. The unique hierarchical structure of our models more accurately captures the nested nature of habitat selection, and allowed for increased discrimination within larger landscapes of suitable habitat. We extrapolated the landscape-scale model to the entire Gunnison Basin because of conservation concerns for this species. We believe this predictive surface is a valuable tool which can be incorporated into land use and conservation planning as well the assessment of future land-use scenarios. ?? 2011 The Wildlife Society.

Multi-scale habitat selection in highly territorial bird species: Exploring the contribution of nest, territory and landscape levels to site choice in breeding rallids (Aves: Rallidae)

NASA Astrophysics Data System (ADS)

Jedlikowski, Jan; Chibowski, Piotr; Karasek, Tomasz; Brambilla, Mattia

2016-05-01

Habitat selection often involves choices made at different spatial scales, but the underlying mechanisms are still poorly understood, and studies that investigate the relative importance of individual scales are rare. We investigated the effect of three spatial scales (landscape, territory, nest-site) on the occurrence pattern of little crake Zapornia parva and water rail Rallus aquaticus at 74 ponds in the Masurian Lakeland, Poland. Habitat structure, food abundance and water chemical parameters were measured at nests and random points within landscape plots (from 300-m to 50-m radius), territory (14-m) and nest-site plots (3-m). Regression analyses suggested that the most relevant scale was territory level, followed by landscape, and finally by nest-site for both species. Variation partitioning confirmed this pattern for water rail, but also highlighted the importance of nest-site (the level explaining the highest share of unique variation) for little crake. The most important variables determining the occurrence of both species were water body fragmentation (landscape), vegetation density (territory) and water depth (at territory level for little crake, and at nest-site level for water rail). Finally, for both species multi-scale models including factors from different levels were more parsimonious than single-scale ones, i.e. habitat selection was likely a multi-scale process. The importance of particular spatial scales seemed more related to life-history traits than to the extent of the scales considered. In the case of our study species, the territory level was highly important likely because both rallids have to obtain all the resources they need (nest site, food and mates) in relatively small areas, the multi-purpose territories they defend.

Comparing Phlebotomy by Tail Tip Amputation, Facial Vein Puncture, and Tail Vein Incision in C57BL/6 Mice by Using Physiologic and Behavioral Metrics of Pain and Distress

PubMed Central

Moore, Elizabeth S; Cleland, Thomas A; Williams, Wendy O; Peterson, Christine M; Singh, Bhupinder; Southard, Teresa L; Pasch, Bret; Labitt, Rachael N; Daugherity, Erin K

2017-01-01

Tail tip amputation with minimal restraint is not widely used for mouse phlebotomy. In part, this infrequency may reflect policies influenced by tail tip amputation procedures for genotyping, which involve greater handling and tissue removal. To assess tail tip amputation with minimal restraint as a phlebotomy technique, we compared it with 2 more common methods: scruffing with facial vein puncture and lateral tail vein incision with minimal restraint. Blood glucose levels, audible and ultrasonic vocalizations, postphlebotomy activity and grooming behavior, open field and elevated plus maze behaviors, nest-building scores, and histologic changes at the phlebotomy site were evaluated. Mice in the facial vein phlebotomy group produced more audible vocalizations, exhibited lower postphlebotomy activity in the open field, and had more severe histologic changes than did mice in the tail incision and tail tip amputation groups. Facial vein phlebotomy did not affect grooming behavior relative to sham groups, whereas tail vein incision—but not tail tip amputation—increased tail grooming compared with that in control mice. Blood glucose levels, nest-building scores, and elevated plus maze behavior did not differ between groups, and no mice in any group produced ultrasonic vocalizations. Tail tip amputation mice did not perform differently than sham mice in any metric analyzed, indicating that this technique is a potentially superior method of blood collection in mice in terms of animal wellbeing. PMID:28535866

Comparing Phlebotomy by Tail Tip Amputation, Facial Vein Puncture, and Tail Vein Incision in C57BL/6 Mice by Using Physiologic and Behavioral Metrics of Pain and Distress.

PubMed

Moore, Elizabeth S; Cleland, Thomas A; Williams, Wendy O; Peterson, Christine M; Singh, Bhupinder; Southard, Teresa L; Pasch, Bret; Labitt, Rachael N; Daugherity, Erin K

2017-05-01

Tail tip amputation with minimal restraint is not widely used for mouse phlebotomy. In part, this infrequency may reflect policies influenced by tail tip amputation procedures for genotyping, which involve greater handling and tissue removal. To assess tail tip amputation with minimal restraint as a phlebotomy technique, we compared it with 2 more common methods: scruffing with facial vein puncture and lateral tail vein incision with minimal restraint. Blood glucose levels, audible and ultrasonic vocalizations, postphlebotomy activity and grooming behavior, open field and elevated plus maze behaviors, nest-building scores, and histologic changes at the phlebotomy site were evaluated. Mice in the facial vein phlebotomy group produced more audible vocalizations, exhibited lower postphlebotomy activity in the open field, and had more severe histologic changes than did mice in the tail incision and tail tip amputation groups. Facial vein phlebotomy did not affect grooming behavior relative to sham groups, whereas tail vein incision-but not tail tip amputation-increased tail grooming compared with that in control mice. Blood glucose levels, nest-building scores, and elevated plus maze behavior did not differ between groups, and no mice in any group produced ultrasonic vocalizations. Tail tip amputation mice did not perform differently than sham mice in any metric analyzed, indicating that this technique is a potentially superior method of blood collection in mice in terms of animal wellbeing.

Linking sex differences in corticosterone with individual reproductive behaviour and hatch success in two species of uniparental shorebirds.

PubMed

Edwards, Darryl B; Chin, Eunice H; Burness, Gary; Gilchrist, H Grant; Schulte-Hostedde, Albrecht I

2013-09-01

In birds, corticosterone (CORT) appears to facilitate reproductive activity because baseline and stress-induced CORT levels are elevated in breeding individuals compared with other times of the year. In particular, CORT is lower in the sex providing most of the parental care (i.e., incubation), which could be an important adaptation to tolerate stressors that result in abandoning reproduction. Therefore, one explanation for sex differences in CORT is that lower levels are favoured during the incubation/parental phase of reproduction. Using two species of uniparental shorebird - polyandrous red phalaropes (Phalaropus fulicarius) and polygynous white-rumped sandpipers (Calidris fuscicollis) - we predicted that the incubating sex would have lower baseline and stress-induced CORT, and incubating individuals with lower CORT would more effectively defend nests against a simulated intrusion, would return more quickly afterwards, and would ultimately have higher hatch success. We found that phalaropes followed the predicted pattern: incubating individuals (males) had lower baseline and stress-induced CORT than females but for baseline CORT these differences existed prior to males commencing incubation. Incubating male phalaropes with lower baseline and stress-induced CORT returned to incubate more quickly after a disturbance and there was non-significant tendency for baseline CORT to be lower in successful nests. In sandpipers, we observed no sex differences and no significant relationships between individual CORT levels and nest defence behaviours or hatch success. Our results demonstrate that in phalaropes at least, selection favours lower baseline and stress-induced CORT during the nesting period. These results can explain sex differences in stress-induced levels of CORT, however sex differences in baseline CORT were present prior to incubation. Copyright © 2013 Elsevier Inc. All rights reserved.

Carbon dioxide sensing in the social context: Leaf-cutting ants prefer elevated CO2 levels to tend their brood.

PubMed

Römer, Daniela; Bollazzi, Martin; Roces, Flavio

2018-07-01

Social insects show temperature and humidity preferences inside their nests to successfully rear brood. In underground nests, ants also encounter rising CO 2 concentrations with increasing depth. It is an open question whether they use CO 2 as a cue to decide where to place and tend the brood. Leaf-cutting ants do show CO 2 preferences for the culturing of their symbiotic fungus. We evaluated their CO 2 choices for brood placement in laboratory experiments. Workers of Acromyrmex lundii in the process of relocating brood were offered a binary choice consisting of two interconnected chambers with different CO 2 concentrations. Values ranged from atmospheric to high concentrations of 4% CO 2 . The CO 2 preferences shown by workers for themselves and for brood placement were assessed by quantifying the number of workers and relocated brood in each chamber. Ants showed clear CO 2 preferences for brood placement. They avoided atmospheric levels, 1% and 4% CO 2 , and showed a preference for levels of 3%. This is the first report of CO 2 preferences for the maintenance of brood in social insects. The observed preferences for brood location were independent of the workers' own CO 2 preferences, since they showed no clear-cut pattern. Workers' CO 2 preferences for brood maintenance were slightly higher than those reported for fungus culturing, although brood is reared in the same chambers as the fungus in leaf-cutting ant nests. Workers' choices for brood placement in natural nests are likely the result of competing preferences for other environmental factors more crucial for brood survival, aside from those for CO 2 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Factors affecting hatch success of hawksbill sea turtles on Long Island, Antigua, West Indies.

PubMed

Ditmer, Mark Allan; Stapleton, Seth Patrick

2012-01-01

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions.

The First Occurrence in the Fossil Record of an Aquatic Avian Twig-Nest with Phoenicopteriformes Eggs: Evolutionary Implications

PubMed Central

Grellet-Tinner, Gerald; Murelaga, Xabier; Larrasoaña, Juan C.; Silveira, Luis F.; Olivares, Maitane; Ortega, Luis A.; Trimby, Patrick W.; Pascual, Ana

2012-01-01

Background We describe the first occurrence in the fossil record of an aquatic avian twig-nest with five eggs in situ (Early Miocene Tudela Formation, Ebro Basin, Spain). Extensive outcrops of this formation reveal autochthonous avian osteological and oological fossils that represent a single taxon identified as a basal phoenicopterid. Although the eggshell structure is definitively phoenicopterid, the characteristics of both the nest and the eggs are similar to those of modern grebes. These observations allow us to address the origin of the disparities between the sister taxa Podicipedidae and Phoenicopteridae crown clades, and traces the evolution of the nesting and reproductive environments for phoenicopteriforms. Methodology/Principal Findings Multi-disciplinary analyses performed on fossilized vegetation and eggshells from the eggs in the nest and its embedding sediments indicate that this new phoenicopterid thrived under a semi-arid climate in an oligohaline (seasonally mesohaline) shallow endorheic lacustine environment. High-end microcharacterizations including SEM, TEM, and EBSD techniques were pivotal to identifying these phoenicopterid eggshells. Anatomical comparisons of the fossil bones with those of Phoenicopteriformes and Podicipediformes crown clades and extinct palaelodids confirm that this avian fossil assemblage belongs to a new and basal phoenicopterid. Conclusions/Significance Although the Podicipediformes-Phoenicopteriformes sister group relationship is now well supported, flamingos and grebes exhibit feeding, reproductive, and nesting strategies that diverge significantly. Our multi-disciplinary study is the first to reveal that the phoenicopteriform reproductive behaviour, nesting ecology and nest characteristics derived from grebe-like type strategies to reach the extremely specialized conditions observed in modern flamingo crown groups. Furthermore, our study enables us to map ecological and reproductive characters on the Phoenicopteriformes evolutionary lineage. Our results demonstrate that the nesting paleoenvironments of flamingos were closely linked to the unique ecology of this locality, which is a direct result of special climatic (high evaporitic regime) and geological (fault system) conditions. PMID:23082136

Factors Affecting Hatch Success of Hawksbill Sea Turtles on Long Island, Antigua, West Indies

PubMed Central

Ditmer, Mark Allan; Stapleton, Seth Patrick

2012-01-01

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions. PMID:22802928

Preliminary analysis of Greater Sage-grouse reproduction in the Virginia Mountains of northwestern Nevada

USGS Publications Warehouse

Coates, Peter S.; Lockyer, Zachary B.; Farinha, Melissa A.; Sweeney, Joelle M.; Johnson, Valerie M.; Meshriy, Matthew G.; Espinosa, Shawn P.; Delehanty, David J.; Casazza, Michael L.

2011-01-01

Relationships between habitat selection and population vital rates of greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse), recently designated as a candidate species under the Endangered Species Act, within the Great Basin are not well-understood. The growing development of renewable energy infrastructure within areas inhabited by sage-grouse is thought to influence predator and vegetation communities. For example, common ravens (Corvus corax), a synanthropic sage-grouse nest predator, are increasing range-wide and select transmission lines and other tall structures for nesting and perching. In the Virginia Mountains of northwestern Nevada, we collected preliminary information of space-use, habitat selection, and population vital rates during the nesting and brood-rearing period over two years on 56 sage-grouse. Additionally, videography at nest sites (n = 22) was used to identify sage-grouse nest predators. The study area is a potential site for renewable energy developments (i.e., wind and solar), and we plan to continue monitoring this population using a before-after-control-impact study design. The results reported here are preliminary and further data are required before conclusions can be drawn from this population of sage-grouse.

Microclimate and nest-site selection in Micronesian Kingfishers

USGS Publications Warehouse

Kesler, Dylan C.; Haig, Susan M.

2005-01-01

We studied the relationship between microclimate and nest-site selection in the Pohnpei Micronesian Kingfisher (Todiramphus cinnamominus reichenbachii) which excavates nest cavities from the mudlike nest structures of arboreal termites (Nasutitermes sp.) or termitaria. Mean daily high temperatures at termitaria were cooler and daily low temperatures were warmer than at random sites in the forest. Results also indicate that termitaria provided insulation from temperature extremes, and that temperatures inside termitaria were within the thermoneutral zone of Micronesian Kingfishers more often than those outside. No differences were identified in temperatures at sites where nest termitaria and nonnest termitaria occurred or among the insulation properties of used and unused termitaria. These results suggest that although termitaria provide insulation from thermal extremes and a metabolically less stressful microclimate, king-fishers did not select from among available termitaria based on their thermal properties. Our findings are relevant to conservation efforts for the critically endangered Guam Micronesian Kingfisher (T. c. cinnamominus) which is extinct in the wild and exists only as a captive population. Captive breeding facilities should provide aviaries with daily ambient temperatures ranging from 22.06 A?C to 28.05 A?C to reduce microclimate-associated metabolic stress and to replicate microclimates used by wild Micronesian Kingfishers.

Compilation of 1990 annual reports of the Navy ELF Communications System Ecological-Monitoring Program. Volume 2. Tabs C thru F. Annual report, Jan-Dec 90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zapotosky, J.E.

1991-08-01

This portion of the report includes monitoring of and data for arthropoda and earthworms; pollinating insects; and small mammals and nesting birds. During the 1990 growing season the ELF antenna was operated more frequently than in prior years. This provides 2 years of intermittent ELF exposure for the biological systems to react to the radiation, one year of very limited exposure and greater exposure in 1990. Arthropod and earthworm sampling was conducted at intervals of two weeks from early May to late October. High voltage transmission lines and magnetic fields have been shown to affect honeybee reproduction, survival, orientation, andmore » nest structure. ELF EM fields could have similar effects on native megachild bees. Changes in cell length, number of cells per nest, number of leaver per cell, orientation of nest entrances, and time to collect a round leaf pierce to cap a cell were monitored. We have not detected significant changes that could be attributed to ELF EM fields. Small mammal and nesting bird biological studies in the western Upper Peninsula of Michigan for the year 1990 are reported.« less

Taxonomy and ecology of a new species of Corynura (Hymenoptera: Halictidae: Augochlorini) from Chile and Argentina.

PubMed

González-Vaquero, Rocío Ana; Polidori, Carlo; Nieves-Aldrey, José Luis

2017-01-16

We describe a new species of Corynura Spinola, a socially polymorphic genus within the bee tribe Augochlorini (Halictidae). We present a detailed description of both sexes of Corynura (Corynura) moscosensis n. sp. González-Vaquero, images of diagnostic morphological structures and antennal sensilla, floral associations, distributional data and notes on its nesting biology. Corynura moscosensis n. sp. is similar in appearance to C. (C.) chloromelas (Alfken), but it can be distinguished by the sculpturing of the mesoscutum and the hair types on the propodeum in the female, and by the genitalia and extent of the area exclusively covered by sensilla placoidea on the antennal flagellum of the male. A lectotype is designated for C. chloromelas. A Chilean Patagonian population of C. moscosensis n. sp. was observed to dig spatially clumped nests in an earth bank with a moderately hard and humid soil. The presence of multiple females within single nest tunnels is unusual and may preliminary suggest nest-sharing, but more data are necessary to define the social organization of this species. The species appears to be polylectic. Bee nests were attacked by satellite flies and possibly velvet ants.

Electrochemical cell design

DOEpatents

Arntzen, John D.

1978-01-01

An electrochemical cell includes two outer electrodes and a central electrode of opposite polarity, all nested within a housing having two symmetrical halves which together form an offset configuration. The outer electrodes are nested within raised portions within the side walls of each housing half while the central electrode sealingly engages the perimetric margins of the side-wall internal surfaces. Suitable interelectrode separators and electrical insulating material electrically isolate the central electrode from the housing and the outer electrodes. The outer electrodes are electrically connected to the internal surfaces of the cell housing to provide current collection. The nested structure minimizes void volume that would otherwise be filled with gas or heavy electrolyte and also provides perimetric edge surfaces for sealing and supporting at the outer margins of frangible interelectrode separator layers.

Double-layer interlaced nested multi-ring array metallic mesh for high-performance transparent electromagnetic interference shielding.

PubMed

Wang, Heyan; Lu, Zhengang; Liu, Yeshu; Tan, Jiubin; Ma, Limin; Lin, Shen

2017-04-15

We report a nested multi-ring array metallic mesh (NMA-MM) that shows a highly uniform diffraction pattern theoretically and experimentally. Then a high-performance transparent electromagnetic interference (EMI) shielding structure is constituted by the double-layer interlaced NMA-MMs separated by transparent quartz-glass substrate. Experimental results show that double-layer interlaced NMA-MM structure exhibits a shielding effectiveness (SE) of over 27 dB in the Ku-band, with a maximal SE of 37 dB at 12 GHz, normalized optical transmittance of 90%, and minimal image quality degradation due to the interlaced arrangement. It thus shows great potential for practical applications in transparent EMI shielding devices.

Fluctuations in a metapopulation of nesting four-toed salamanders, Hemidactylium scutatum, in the Great Smoky Mountains National Park, USA, 1999-2003

USGS Publications Warehouse

Corser, J.D.; Dodd, C.K.

2004-01-01

We tested two predictions associated with the hypothesis that certain populations of pond-breeding amphibians are structured into metapopulations using minimum relative abundance estimates of nesting four-toed salamanders (Hemidactylium scutatum Schlegel) from 11 different ponds in the Great Smoky Mountains National Park. Coefficients of variation (CV) for counts at individual ponds ranged from 0.25 to 1.26, and the overall mean CV at all 11 ponds was 0.34. Many pairs of ponds had negative correlations in abundance from 1999-2003, whereas others had various degrees of positive correlation (mean r = 0.29). Thus, nesting population size fluctuated semi-independently among the ponds from year to year, inferring the existence of inter-pond dispersal. The mean number of nesting females at a pond was negatively, but non-significantly, correlated (r = -0.27; P = 0.40; 10 d.f.) to the pond's isolation. Owing to physiological constraints on plethodontid salamander energetics, precipitation during the nesting season (February and March) appeared to play an important role (r = 0.78; P = 0.12; 4 d.f.) in the number of nesting females we observed. Unlike some other plethodontid salamander populations in more fragmented southern Appalachian forest ecosystems, this (meta)population within Great Smoky Mountains National Park does not appear to be declining.

North American osprey populations and contaminants: Historic and contemporary perspectives

USGS Publications Warehouse

Henny, Charles J.; Grove, Robert A.; Kaiser, James L.; Johnson, Branden L.

2010-01-01

Osprey (Pandion haliaetus) populations were adversely affected by DDT and perhaps other contaminants in the United States and elsewhere. Reduced productivity, eggshell thinning, and high DDE concentrations in eggs were the signs associated with declining osprey populations in the 1950s, 1960s, and 1970s. The species was one of the first studied on a large scale to bring contaminant issues into focus. Although few quantitative population data were available prior to the 1960s, many osprey populations in North America were studied during the 1960s and 1970s with much learned about basic life history and biology. This article reviews the historical and current effects of contaminants on regional osprey populations. Breeding populations in many regions of North America showed post-DDT-era (1972) population increases of varying magnitudes, with many populations now appearing to stabilize at much higher numbers than initially reported in the 1970s and 1980s. However, the magnitude of regional population increases in the United States between 1981 (first Nationwide Survey, ∼8,000 pairs), when some recovery had already occurred, 1994 (second survey, ∼14,200), and 2001 (third survey, ∼16,000–19,000), or any other years, is likely not a simple response to the release from earlier contaminant effects, but a response to multi-factorial effects. This indirect “contaminant effects” measurement comparing changes (i.e., recovery) in post-DDT-era population numbers over time is probably confounded by changing human attitudes toward birds of prey (shooting, destroying nests, etc.), changing habitats, changing fish populations, and perhaps competition from other species. The species' adaptation to newly created reservoirs and its increasing use of artificial nesting structures (power poles, nesting platforms, cell towers, channel markers, offshore duck blinds, etc.) are two important factors. The timing of the initial use of artificial nesting structures, which replaced declining numbers of suitable trees at many locations, varied regionally (much later in the western United States and Mexico). Because of the increasing use of artificial nesting structures, there may be more ospreys nesting in North America now than ever before. Now, with the impact of most legacy organic contaminants (DDT, other organochlorine [OC] pesticides, polychlorinated biphenyls [PCB], polychlorinated dibenzo-p-dioxins [PCDD], polychlorinated dibenzofurans (PCDF]) greatly reduced or eliminated, and some osprey populations showing evidence of stabilizing, the species was proposed as a Worldwide Sentinel Species for evaluating emerging contaminants. Several emerging contaminants are already being studied, such as polybrominated diphenyl ethers (PBDE) and perfluorinated acids and sulfonate compounds (PFC). The many advantages for continued contaminant investigations using the osprey include a good understanding of its biology and ecology, its known distribution and abundance, and its ability to habituate to humans and their activities, which permits nesting in some of the potentially most contaminated environments. It is a top predator in most ecosystems, and its nests are relatively easy to locate and study with little researcher impact on reproductive success.

A demonstration of nesting in two antarctic icefish (genus Chionodraco) using a fin dimorphism analysis and ex situ videos.

PubMed

Ferrando, Sara; Castellano, Laura; Gallus, Lorenzo; Ghigliotti, Laura; Masini, Maria Angela; Pisano, Eva; Vacchi, Marino

2014-01-01

Visual observations and videos of Chionodraco hamatus icefish at the "Acquario di Genova" and histological analyses of congeneric species C. hamatus and C. rastrospinosus adults sampled in the field provided new anatomical and behavioral information on the reproductive biology of these white blooded species that are endemic to the High-Antarctic region. During the reproductive season, mature males of both species, which are different from females and immature males, display fleshy, club-like knob modifications of their anal fin that consisted of a much thicker epithelium. Histology indicated that the knobs were without any specialized glandular or sensorial organization, thus suggesting a mechanical and/or ornamental role of the modified anal fin. In addition, the occurrence of necrotic regions at the base of the thickened epithelium and the detachment of the knobs in post-spawning C. hamatus males indicated the temporary nature of the knobs. The role of these structures was confirmed as mechanical and was clarified using visual observations and videos of the behavior of two C. hamatus during a reproductive event that occurred in an exhibit tank at the "Acquario di Genova". The reproductive process included pre-spawning activity, preparation of the nest, egg guarding and successfully ended with egg hatching. When the spawning event approached, the male prepared the nest. The nest was constructed on an accurately selected bottom surface, which was flattened and maintained free from sand or debris by a combination of radial body movements and continuous anal fin sweeping, thus demonstrating the important mechanical/abrasive function of the anal fin knobs. The present data are the first records of active nesting in icefish and clarify the meaning of dimorphic temporary structures, whose function would have been difficult to obtain in the field.

Considering Spatial Scale and Reproductive Consequences of Habitat Selection when Managing Grasslands for a Threatened Species

PubMed Central

Pearson, Scott F.; Knapp, Shannon M.

2016-01-01

Habitat selection that has fitness consequences has important implications for conservation activities. For example, habitat characteristics that influence nest success in birds can be manipulated to improve habitat quality with the goal of ultimately improving reproductive success. We examined habitat selection by the threatened streaked horned lark (Eremophila alpestris strigata) at both the breeding-site (territory) and nest-site scales. Larks were selective at both spatial scales but with contrasting selection. At the territory scale, male larks selected sparsely vegetated grasslands with relatively short vegetation. At the nest-site scale, female larks selected sites within territories with higher vegetation density and more perennial forbs. These nest-site scale choices had reproductive consequences, with greater nest success in areas with higher densities of perennial forbs. We experimentally manipulated lark habitat structure in an attempt to mimic the habitat conditions selected by larks by using late summer prescribed fires. After the burn, changes in vegetation structure were in the direction preferred by larks but habitat effects attenuated by the following year. Our results highlight the importance of evaluating habitat selection at spatial scales appropriate to the species of interest, especially when attempting to improve habitat quality for rare and declining species. They also highlight the importance of conducting restoration activities in a research context. For example, because the sparsely vegetated conditions created by fire attenuate, there may be value in examining more frequent burns or hotter fires as the next management and research action. We hope the design outlined in this study will serve as an integrated research and management example for conserving grassland birds generally. PMID:27322196

Factors related to the recovery of subalpine woodland on Mauna Kea, Hawaii

USGS Publications Warehouse

Hess, Steven C.; Banko, Paul C.; Brenner, Gregory J.; Jacobi, James D.

1999-01-01

We measured mature tree and sapling density, tree associations, crown size, age structure, recovery from ungulate browsing, and grass cover at four study sites in two types of subalpine woodland on Mauna Kea volcano, island of Hawaii. Beginning in 1981, introduced ungulates were reduced in number to allow regeneration of Sophora chrysophylla (mamane) in habitat supporting the endangered Hawaiian finch, Loxioides bailleui (palila). We found Sophora regeneration at all four study sites, but regeneration was higher in mixed species woodland with codominant Myoporum sandwicense (naio) than in areas where Sophora dominated. Regeneration of Myoporum was uniformly very low in comparison. Invasive grass cover, which suppresses Sophora germination, was highest in mid-elevation woodland where Sophora dominated. The distribution of mature and sapling Sophora were both related to study site, reflecting previous ungulate browsing and uneven recovery due to grasses. Densities of Sophora snags were not different among any of the sites, suggesting a more even distribution in the past. Selective browsing before ungulate reduction may have favored Myoporum over Sophora, leading to high densities of mature Myoporum in codominant woodland. After ungulate reduction, however, we found no pattern of competitive inhibition by Myoporum on regeneration of Sophora. Reduction of Myoporum is not likely to enhance habitat for Loxioides as much as supplemental planting of Sophora, grass control, and continued ungulate eradication. Mid-elevation Sophora woodland areas, where Loxioides forage and nest in high densities, would benefit the most from these management actions.

Effects of hydropeaking on the spawning behaviour of Atlantic salmon Salmo salar and brown trout Salmo trutta.

PubMed

Vollset, K W; Skoglund, H; Wiers, T; Barlaup, B T

2016-06-01

An in situ camera set-up was used to study the spawning activity of Atlantic salmon Salmo salar and brown trout Salmo trutta throughout two consecutive seasons in a spawning area affected by hydropower-related pulse flows due to hydropeaking. The purpose was to test whether the flow variation discouraged spawning in shallow areas or motivated spawning into areas with elevated risk of incubation mortality. There were more S. salar observed on the spawning ground during days with high discharge. The presence of S. salar in the spawning grounds was not affected by the hydropeaking cycles of the preceding night. Female S. salar were observed preparing nests within the first hour after water discharge had increased to levels suitable for spawning. In contrast, the number of S. trutta was not correlated with flow and nest preparation was also observed at a discharge corresponding to the lowest discharge levels during a hydropeaking cycle. Survival was generally high in nests excavated the following winter, with only 5·4% suffering mortality due to dewatering. The results suggest that S. salar may respond rapidly to variable-flow conditions and utilize short windows with suitable flows for spawning. Smaller S. trutta may utilize low-flow conditions to spawn in areas that are not habitable by larger S. salar during low flow. © 2016 The Fisheries Society of the British Isles.

The Rocky Mountain population of the western Canada goose: its distribution, habitats, and management

USGS Publications Warehouse

Krohn, William B.; Bizeau, Elwood G.

1980-01-01

The western Canada goose (Branta canadensis moffitti) was divided into a Rocky Mountain population (RMP) and a Pacific population (PP) on the basis of band recovery patterns examined in this study and recovery data from other investigators. Habitat information obtained from nine cooperating wildlife agencies within the RMP's range provided a base line for evaluating future changes in nesting, molting, and wintering areas. The habitat inventory indicated that none of the seasonal habitats were currently limiting the size of the RMP. The RMP's range is divided into 15 reference areas and these are briefly described. Past studies of Canada geese in the Intermountain Region are reviewed. Topics covered in the discussion of breeding biology are nesting chronology, spring population composition, breeding age, clutch size, nesting success. artificial nesting structures, and gosling survival. Much of the mortality of Canada geese occurs before the birds are fledged. Man-made nesting structures reduce losses during incubation. but research is needed on the relations between brooding sites and gosling survival. Some western Canada geese, mainly prebreeders and unsuccessful nesters, make molt migrations to and from molting areas during and after the brood-rearing season. More than half of these molt-migrants are yearlings too young to nest; there are indications that even some successful nesters leave nesting areas to molt before the fledging of their offspring. Geese 2 years old or older may serve as guides to traditional molting areas for the first-time migrants (i.e., yearlings). Lack of disturbance appears to influence selection of specific molting areas within the nesting range of moffitti, whereas movements of molters out of the Intermountain Region may be related to the evolution of this subspecies. Apparently. molters of both the PP and RMP that leave the Region go to the Northwest Territories of Canada. Although the taxonomic status of moffitti as related to the giant Canada goose (B. c. maxima) is unclear. these two subspecies are closely related. as evidenced by similar molt migrations to subarctic Canada. similar blood serum proteins. and only dinal differences in body size ,!!nd color. Mean annual survival rates for birds banded on nesting areas averaged 53 ? 2% (X ? SE) for immatures and 64 ? 1 % for adults. Mean annual survival rates of adults captured on molting areas averaged 70 ? 1 %. Sport hunting accounts for more than 86% of the mortality of fledged Rocky Mountain geese. and hunting may limit the population's growth. Because the number of waterfowl hunters in the Rocky Mountain West is increasing, the continued expansion or future maintenance of the RMP may require more restrictive hunting regulations. Other management recommendations include the refinement and standardization of spring and winter aerial surveys, and more accurate age and sex determinations when geese are banded and color-marked.

Forgiveness, coping, and terrorism: do tendency to forgive and coping strategies associate with the level of posttraumatic symptoms of injured victims of terror attacks?

PubMed

Weinberg, Michael; Gil, Sharon; Gilbar, Ora

2014-07-01

The study examined the tendency to forgive (self, others, and situations) and coping strategies (problem-focused, emotion-focused, and avoidance) among terror attack victims as associated with posttraumatic stress disorder (PTSD) symptom severity. The sample included 108 terror victims who had been injured in terror attacks (mean age 46.23, standard deviation = 11.61; 58.3% male). Participants agreed to undergo assessments of their PTSD symptoms, coping strategies, and tendency to forgive. A nested structural equation model design showed that tendency to forgive is positively associated with problem-focused coping and negatively associated with avoidance coping. Additionally, tendency to forgive and problem-focused coping are associated with decreased PTSD symptom severity, whereas emotion-focused coping is associated with elevated PTSD symptom severity. Tendency to forgive and coping strategies are significantly associated with each other and with severity of PTSD symptoms among individuals injured in terror attacks. Theoretical and clinical implications of the findings are discussed. © 2013 Wiley Periodicals, Inc.

Plasma cytokine levels and risk of HIV type 1 (HIV-1) transmission and acquisition: a nested case-control study among HIV-1-serodiscordant couples.

PubMed

Kahle, Erin M; Bolton, Michael; Hughes, James P; Donnell, Deborah; Celum, Connie; Lingappa, Jairam R; Ronald, Allan; Cohen, Craig R; de Bruyn, Guy; Fong, Youyi; Katabira, Elly; McElrath, M Juliana; Baeten, Jared M

2015-05-01

A heightened proinflammatory state has been hypothesized to enhance human immunodeficiency virus type 1 (HIV-1) transmission - both susceptibility of HIV-1-exposed persons and infectiousness of HIV-1-infected persons. Using prospective data from heterosexual African couples with HIV-1 serodiscordance, we conducted a nested case-control analysis to assess the relationship between cytokine concentrations and the risk of HIV-1 acquisition. Case couples (n = 120) were initially serodiscordant couples in which HIV-1 was transmitted to the seronegative partner during the study; control couples (n = 321) were serodiscordant couples in which HIV-1 was not transmitted to the seronegative partner. Differences in a panel of 30 cytokines were measured using plasma specimens from both HIV-1-susceptible and HIV-1-infected partners. Plasma was collected before seroconversion for cases. For both HIV-1-infected and HIV-1-susceptible partners, cases and controls had significantly different mean responses in cytokine panels (P < .001, by the Hotelling T(2) test), suggesting a broadly different pattern of immune activation for couples in which HIV-1 was transmitted, compared with couples without transmission. Individually, log10 mean concentrations of interleukin 10 (IL-10) and CXCL10 were significantly higher for both HIV-1-susceptible and HIV-1-infected case partners, compared with HIV-1-susceptible and HIV-1-infected control partners (P < .01 for all comparisons). In multivariate analysis, HIV-1 transmission was significantly associated with elevated CXCL10 concentrations in HIV-1-susceptible partners (P = .001) and with elevated IL-10 concentrations in HIV-1-infected partners (P = .02). Immune activation, as measured by levels of cytokine markers, particularly elevated levels of IL-10 and CXCL1, are associated with increased HIV-1 susceptibility and infectiousness. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Inventory of montane-nesting birds in Katmai and Lake Clark national parks and preserves

USGS Publications Warehouse

Ruthrauff, Daniel R.; Tibbitts, Lee; Gill, Robert E.; Handel, Colleen M.

2007-01-01

As part of the National Park Service’s Inventory and Monitoring Program, biologists from the U. S. Geological Survey’s Alaska Science Center conducted an inventory of birds in montane regions of Katmai and Lake Clark National Parks and Preserves during 2004–2006. We used a stratified random survey design to allocate samples by ecological subsection. To survey for birds, we conducted counts at 468 points across 29, 10-km x 10-km (6.2-mi x 6.2-mi) sample plots in Katmai and 417 points across 25, 10-km x 10-km sample plots in Lake Clark. We detected 92 and 104 species in Katmai and Lake Clark, respectively, including 40 species of conservation concern. We detected three species not previously recorded in Katmai (Ring-necked Duck [Aythya collaris], Lesser Scaup [Aythya affinis], and White-tailed Ptarmigan [Lagopus leucurus]) and two species not previously recorded in Lake Clark (Northern Flicker [Colaptes auratus ] and Olive-sided Flycatcher [Contopus cooperi]). The most commonly detected species in both parks was Golden-crowned Sparrow (Zonotrichia atricapilla); Fox Sparrow (Passerella iliaca) and American Pipit (Anthus rubescens) were abundant and widely-distributed as well. We defined sites as low (100–350 m), middle (351–600 m), or high (601–1,620 m) elevation based on the distribution of vegetation cover, and similarly categorized the 34 most-commonly detected species based on the mean elevation of sample points at which they were detected. High elevation (i.e., alpine) sites were characterized by high percent cover of dwarf shrub and bare ground habitat and supported species like Rock Ptarmigan (L. mutus), American Golden-Plover (Pluvialis dominica), Wandering Tattler (Tringa incana), Surfbird (Aphriza virgata), and Snow Bunting (Plectrophenax nivalis), all species of conservation concern. This inventory represents the first systematic survey of birds nesting in montane regions of both parks. Results from this inventory can form the foundation of subsequent monitoring efforts

New heterogeneous test statistics for the unbalanced fixed-effect nested design.

PubMed

Guo, Jiin-Huarng; Billard, L; Luh, Wei-Ming

2011-05-01

When the underlying variances are unknown or/and unequal, using the conventional F test is problematic in the two-factor hierarchical data structure. Prompted by the approximate test statistics (Welch and Alexander-Govern methods), the authors develop four new heterogeneous test statistics to test factor A and factor B nested within A for the unbalanced fixed-effect two-stage nested design under variance heterogeneity. The actual significance levels and statistical power of the test statistics were compared in a simulation study. The results show that the proposed procedures maintain better Type I error rate control and have greater statistical power than those obtained by the conventional F test in various conditions. Therefore, the proposed test statistics are recommended in terms of robustness and easy implementation. ©2010 The British Psychological Society.

A 3-level Bayesian mixed effects location scale model with an application to ecological momentary assessment data.

PubMed

Lin, Xiaolei; Mermelstein, Robin J; Hedeker, Donald

2018-06-15

Ecological momentary assessment studies usually produce intensively measured longitudinal data with large numbers of observations per unit, and research interest is often centered around understanding the changes in variation of people's thoughts, emotions and behaviors. Hedeker et al developed a 2-level mixed effects location scale model that allows observed covariates as well as unobserved variables to influence both the mean and the within-subjects variance, for a 2-level data structure where observations are nested within subjects. In some ecological momentary assessment studies, subjects are measured at multiple waves, and within each wave, subjects are measured over time. Li and Hedeker extended the original 2-level model to a 3-level data structure where observations are nested within days and days are then nested within subjects, by including a random location and scale intercept at the intermediate wave level. However, the 3-level random intercept model assumes constant response change rate for both the mean and variance. To account for changes in variance across waves, as well as clustering attributable to waves, we propose a more comprehensive location scale model that allows subject heterogeneity at baseline as well as across different waves, for a 3-level data structure where observations are nested within waves and waves are then further nested within subjects. The model parameters are estimated using Markov chain Monte Carlo methods. We provide details on the Bayesian estimation approach and demonstrate how the Stan statistical software can be used to sample from the desired distributions and achieve consistent estimates. The proposed model is validated via a series of simulation studies. Data from an adolescent smoking study are analyzed to demonstrate this approach. The analyses clearly favor the proposed model and show significant subject heterogeneity at baseline as well as change over time, for both mood mean and variance. The proposed 3-level location scale model can be widely applied to areas of research where the interest lies in the consistency in addition to the mean level of the responses. Copyright © 2018 John Wiley & Sons, Ltd.

Beyond habitat structure: Landscape heterogeneity explains the monito del monte (Dromiciops gliroides) occurrence and behavior at habitats dominated by exotic trees.

PubMed

Salazar, Daniela A; Fontúrbel, Francisco E

2016-09-01

Habitat structure determines species occurrence and behavior. However, human activities are altering natural habitat structure, potentially hampering native species due to the loss of nesting cavities, shelter or movement pathways. The South American temperate rainforest is experiencing an accelerated loss and degradation, compromising the persistence of many native species, and particularly of the monito del monte (Dromiciops gliroides Thomas, 1894), an arboreal marsupial that plays a key role as seed disperser. Aiming to compare 2 contrasting habitats (a native forest and a transformed habitat composed of abandoned Eucalyptus plantations and native understory vegetation), we assessed D. gliroides' occurrence using camera traps and measured several structural features (e.g. shrub and bamboo cover, deadwood presence, moss abundance) at 100 camera locations. Complementarily, we used radio telemetry to assess its spatial ecology, aiming to depict a more complete scenario. Moss abundance was the only significant variable explaining D. gliroides occurrence between habitats, and no structural variable explained its occurrence at the transformed habitat. There were no differences in home range, core area or inter-individual overlapping. In the transformed habitats, tracked individuals used native and Eucalyptus-associated vegetation types according to their abundance. Diurnal locations (and, hence, nesting sites) were located exclusively in native vegetation. The landscape heterogeneity resulting from the vicinity of native and Eucalyptus-associated vegetation likely explains D. gliroides occurrence better than the habitat structure itself, as it may be use Eucalyptus-associated vegetation for feeding purposes but depend on native vegetation for nesting. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Hydrologic connectivity: Quantitative assessments of hydrologic-enforced drainage structures in an elevation model

USGS Publications Warehouse

Poppenga, Sandra K.; Worstell, Bruce B.

2016-01-01

Elevation data derived from light detection and ranging present challenges for hydrologic modeling as the elevation surface includes bridge decks and elevated road features overlaying culvert drainage structures. In reality, water is carried through these structures; however, in the elevation surface these features impede modeled overland surface flow. Thus, a hydrologically-enforced elevation surface is needed for hydrodynamic modeling. In the Delaware River Basin, hydrologic-enforcement techniques were used to modify elevations to simulate how constructed drainage structures allow overland surface flow. By calculating residuals between unfilled and filled elevation surfaces, artificially pooled depressions that formed upstream of constructed drainage structure features were defined, and elevation values were adjusted by generating transects at the location of the drainage structures. An assessment of each hydrologically-enforced drainage structure was conducted using field-surveyed culvert and bridge coordinates obtained from numerous public agencies, but it was discovered the disparate drainage structure datasets were not comprehensive enough to assess all remotely located depressions in need of hydrologic-enforcement. Alternatively, orthoimagery was interpreted to define drainage structures near each depression, and these locations were used as reference points for a quantitative hydrologic-enforcement assessment. The orthoimagery-interpreted reference points resulted in a larger corresponding sample size than the assessment between hydrologic-enforced transects and field-surveyed data. This assessment demonstrates the viability of rules-based hydrologic-enforcement that is needed to achieve hydrologic connectivity, which is valuable for hydrodynamic models in sensitive coastal regions. Hydrologic-enforced elevation data are also essential for merging with topographic/bathymetric elevation data that extend over vulnerable urbanized areas and dynamic coastal regions.

RedeR: R/Bioconductor package for representing modular structures, nested networks and multiple levels of hierarchical associations

PubMed Central

2012-01-01

Visualization and analysis of molecular networks are both central to systems biology. However, there still exists a large technological gap between them, especially when assessing multiple network levels or hierarchies. Here we present RedeR, an R/Bioconductor package combined with a Java core engine for representing modular networks. The functionality of RedeR is demonstrated in two different scenarios: hierarchical and modular organization in gene co-expression networks and nested structures in time-course gene expression subnetworks. Our results demonstrate RedeR as a new framework to deal with the multiple network levels that are inherent to complex biological systems. RedeR is available from http://bioconductor.org/packages/release/bioc/html/RedeR.html. PMID:22531049

Resting-Associated Vocalization Emitted by Captive Asian House Shrews (Suncus murinus): Acoustic Structure and Variability in an Unusual Mammalian Vocalization

PubMed Central

Schneiderová, Irena; Zouhar, Jan

2014-01-01

Shrews have rich vocal repertoires that include vocalizations within the human audible frequency range and ultrasonic vocalizations. Here, we recorded and analyzed in detail the acoustic structure of a vocalization with unclear functional significance that was spontaneously produced by 15 adult, captive Asian house shrews (Suncus murinus) while they were lying motionless and resting in their nests. This vocalization was usually emitted repeatedly in a long series with regular intervals. It showed some structural variability; however, the shrews most frequently emitted a tonal, low-frequency vocalization with minimal frequency modulation and a low, non-vocal click that was clearly noticeable at its beginning. There was no effect of sex, but the acoustic structure of the analyzed vocalizations differed significantly between individual shrews. The encoded individuality was low, but it cannot be excluded that this individuality would allow discrimination of family members, i.e., a male and female with their young, collectively resting in a common nest. The question remains whether the Asian house shrews indeed perceive the presence of their mates, parents or young resting in a common nest via the resting-associated vocalization and whether they use it to discriminate among their family members. Additional studies are needed to explain the possible functional significance of resting-associated vocalizations emitted by captive Asian house shrews. Our study highlights that the acoustic communication of shrews is a relatively understudied topic, particularly considering that they are highly vocal mammals. PMID:25390304

Nested high resolution models for the coastal areas of the North Indian Ocean

NASA Astrophysics Data System (ADS)

Wobus, Fred; Shapiro, Georgy

2017-04-01

Oceanographic processes at coastal scales require much higher horizontal resolution from both ocean models and observations as compared to deep water oceanography. Aside from a few exceptions such as land-locked seas, the hydrodynamics of coastal shallow waters is strongly influenced by the tides, which in turn control the mixing, formation of temperature fronts and other phenomena. The numerical modelling of the coastal domains requires good knowledge of the lateral boundary conditions. The application of lateral boundary conditions to ocean models is a notoriously tricky task, but can only be avoided with global ocean models. Smaller scale regional ocean models are typically nested within global models, and even smaller-scale coastal models may be nested within regional models, creating a nesting chain. However a direct nesting of a very high resolution coastal model into a coarse resolution global model results in degrading of the accuracy of the outputs due to the large difference between the model resolutions. This is why a nesting chain has to be applied, so that every increase in resolution is kept within a reasonable minimum (typically by a factor of 3 to 5 at each step). Global models are traditionally non-tidal, so at some stage of the nesting chain the tides need to be introduced. This is typically done by calculating the tidal constituents from a dedicated tidal model (e.g. TPXO) for all boundary points of a nested model. The tidal elevation at each boundary location can then be calculated from the harmonics at every model time step and the added to the parent model non-tidal SSH. This combination of harmonics-derived tidal SSH and non-tidal parent model SSH is typically applied to the nested domain using the Flather condition, together with the baroclinic velocities from the parent model. The harmonics-derived SSH cannot be added to an SSH signal that is already tidal, so the parent model SSH has to be either detided or taken from a non-tidal model. Due to the lack of effective detiding methods and the prevailing view that harmonics-derived SSH provide a cleaner tidal signal over the SSH taken from a tidal parent model it has traditionally only been the last model in a nesting chain that is tidal. But to our knowledge these assumptions haven't been sufficiently tested and need to be re-visited. Furthermore, the lack of tides in the larger-scale regional models limits their capability and we would like to push for a nesting chain where all regional models (including the intermediate ones) are tidal. In this study we have conducted a number of numerical experiments where we have tested whether a tidal regional model can effectively force a tidal nested model without resorting to detiding techniques and the use of a dedicated tidal model such as TPXO. We have tested whether it's possible to use a tidal parent model and use the total SSH (combined geostrophic SSH and tidal component) to force the child model at the boundary. We call this strategy "tidal nesting" as opposed to TPXO tidal forcing which is used in "traditional nesting". For our experiments we have developed 2 models based on the same NEMO 3.6 codebase. The medium resolution AS20 model covers the Arabian Sea at 1/20 ̊ with 50 layers using a hybrid s-on-top-of-z vertical discretisation scheme (Shapiro et al., 2013); and the high resolution AG60 model covers the Arabian/Persian Gulf at 1/60 ̊ with 50 layers. The AS20 model is "traditionally" nested within the UK Met Office non-tidal large-scale Indian Ocean model at 1/12 ̊ resolution and tidal constituents at the boundary are taken from the TPXO7.2 Global Tidal Solution. Our "tidal nesting" experiments use different forcing frequencies at which the tidal SSH is fed from the larger-scale AS20 into the smaller-scale AG60 model. These strategies are compared with "traditional nesting" where the inner AG60 uses boundary conditions from a non-tidal AS20 parent model and tides are computed from TPXO harmonics. The results reveal an optimal tidal nesting strategy which forces tidal SSH from the parent model at 1-hourly intervals whilst non-tidal parameters are forced at 24-hourly intervals. The analysis includes comparisons with tidal gauges in the Gulf of Oman and inside the Arabian Gulf. The accuracy of tides inside the Gulf is inhibited by the narrow Straits of Hormuz, and tidal nesting doesn't achieve the same level of agreement with observation as traditional nesting. We also found that a further increase in the SSH forcing frequency to 30 minutes does not further improve the results. The forcing at intervals of 1h/24h for tidal/non-tidal parameters shows that a 2-step tidal nesting chain is viable and thus tides can be represented in more than just the last model of a nesting chain. References: Shapiro, G., Luneva, M., Pickering, J., and Storkey, D.: The effect of various vertical discretization schemes and horizontal diffusion parameterization on the performance of a 3-D ocean model: the Black Sea case study, Ocean Sci., 9, 377-390, doi:10.5194/os-9-377-2013, 2013.

Species-specific variation in nesting and postfledging resource selection for two forest breeding migrant songbirds.

PubMed

Jenkins, Julianna M A; Thompson, Frank R; Faaborg, John

2017-01-01

Habitat selection is a fundamental component of community ecology, population ecology, and evolutionary biology and can be especially important to species with complex annual habitat requirements, such as migratory birds. Resource preferences on the breeding grounds may change during the postfledging period for migrant songbirds, however, the degree to which selection changes, timing of change, and whether all or only a few species alter their resource use is unclear. We compared resource selection for nest sites and resource selection by postfledging juvenile ovenbirds (Seiurus aurocapilla) and Acadian flycatchers (Empidonax virescens) followed with radio telemetry in Missouri mature forest fragments from 2012-2015. We used Bayesian discrete choice modeling to evaluate support for local vegetation characteristics on the probability of selection for nest sites and locations utilized by different ages of postfledging juveniles. Patterns of resource selection variation were species-specific. Resource selection models indicated that Acadian flycatcher habitat selection criteria were similar for nesting and dependent postfledging juveniles and selection criteria diverged when juveniles became independent from adults. After independence, flycatcher resource selection was more associated with understory foliage density. Ovenbirds differed in selection criteria between the nesting and postfledging periods. Fledgling ovenbirds selected areas with higher densities of understory structure compared to nest sites, and the effect of foliage density on selection increased as juveniles aged and gained independence. The differences observed between two sympatric forest nesting species, in both the timing and degree of change in resource selection criteria over the course of the breeding season, illustrates the importance of considering species-specific traits and postfledging requirements when developing conservation efforts, especially when foraging guilds or prey bases differ. We recommend that postfledging habitat selection be considered in future conservation efforts dealing with Neotropical migrants and other forest breeding songbirds.

From endogenous to exogenous pattern formation: Invasive plant species changes the spatial distribution of a native ant.

PubMed

Li, Kevin; He, Yifan; Campbell, Susanna K; Colborn, A Shawn; Jackson, Eliot L; Martin, Austin; Monagan, Ivan V; Ong, Theresa Wei Ying; Perfecto, Ivette

2017-06-01

Invasive species are a significant threat to global biodiversity, but our understanding of how invasive species impact native communities across space and time remains limited. Based on observations in an old field in Southeast Michigan spanning 35 years, our study documents significant impacts of habitat change, likely driven by the invasion of the shrub, Elaeagnus umbellata, on the nest distribution patterns and population demographics of a native ant species, Formica obscuripes. Landcover change in aerial photographs indicates that E. umbellata expanded aggressively, transforming a large proportion of the original open field into dense shrubland. By comparing the ant's landcover preferences before and after the invasion, we demonstrate that this species experienced a significant unfavorable change in its foraging areas. We also find that shrub landcover significantly moderates aggression between nests, suggesting nests are more related where there is more E. umbellata. This may represent a shift in reproductive strategy from queen flights, reported in the past, to asexual nest budding. Our results suggest that E. umbellata may affect the spatial distribution of F. obscuripes by shifting the drivers of nest pattern formation from an endogenous process (queen flights), which led to a uniform pattern, to a process that is both endogenous (nest budding) and exogenous (loss of preferred habitat), resulting in a significantly different clustered pattern. The number and sizes of F. obscuripes nests in our study site are projected to decrease in the next 40 years, although further study of this population's colony structures is needed to understand the extent of this decrease. Elaeagnus umbellata is a common invasive shrub, and similar impacts on native species might occur in its invasive range, or in areas with similar shrub invasions. © 2017 John Wiley & Sons Ltd.

Hybrid chalcogenide nanoparticles: 2D-WS2 nanocrystals inside nested WS2 fullerenes.

PubMed

Hoshyargar, Faegheh; Corrales, Tomas P; Branscheid, Robert; Kolb, Ute; Kappl, Michael; Panthöfer, Martin; Tremel, Wolfgang

2013-10-28

The MOCVD assisted formation of nested WS2 inorganic fullerenes (IF-WS2) was performed by enhancing surface diffusion with iodine, and fullerene growth was monitored by taking TEM snapshots of intermediate products. The internal structure of the core-shell nanoparticles was studied using scanning electron microscopy (SEM) after cross-cutting with a focused ion beam (FIB). Lamellar reaction intermediates were found occluded in the fullerene particles. In contrast to carbon fullerenes, layered metal chalcogenides prefer the formation of planar, plate-like structures where the dangling bonds at the edges are stabilized by excess S atoms. The effects of the reaction and annealing temperatures on the composition and morphology of the final product were investigated, and the strength of the WS2 shell was measured by intermittent contact-mode AFM. The encapsulated lamellar structures inside the hollow spheres may lead to enhanced tribological activities.

Multiple functions of a multi-component mating pheromone in sea lamprey Petromyzon marinus

USGS Publications Warehouse

Johnson, N.S.; Yun, S.-S.; Buchinger, T.J.; Li, W.

2012-01-01

The role of the C24 sulphate in the mating pheromone component, 7α,12α,24-trihydroxy-5α-cholan-3-one 24-sulphate (3kPZS), to specifically induce upstream movement in ovulated female sea lampreys Petromyzon marinus was investigated. 7α,12α-dihydroxy-5α-cholan-3-one 24-oic acid (3kACA), a structurally similar bile acid released by spermiated males, but lacking the C24 sulphate ester, was tested in bioassays at concentrations between 10−11 and 10−14 molar (M). 3kACA did not induce upstream movement in females or additional reproductive behaviours. In contrast, spermiated male washings induced upstream movement, prolonged retention on a nest and induced an array of nesting behaviours. Differential extraction and elution by solid-phase extraction resins showed that components other than 3kPZS + 3kACA are necessary to retain females on nests and induce nest cleaning behaviours. All pheromone components, including components in addition to 3kPZS + 3kACA that retain females and induce nest cleaning behaviours were released from the anterior region of the males, as had been reported for 3kPZS. It is concluded that the sea lamprey male mating pheromone has multiple functions and is composed of multiple components.

Receivers matter: the meaning of alarm calls and competition for nest sites in a bird community.

PubMed

Parejo, Deseada; Avilés, Jesús M; Expósito-Granados, Mónica

2018-04-11

Animal communities may constitute information networks where individuals gain information on predation risk by eavesdropping on alarm calls of other species. However, communities include species in different trophic levels, and it is not yet known how the trophic level of the receiver influences the informative value of a call. Furthermore, no empirical study has yet tested how increased competition may influence the value of alarm calls for distinct receivers. Here, we identify the importance of alarm calls emitted by a small owl, the little owl (Athene noctua), on the structure of a cavity-nesting bird community including mesopredators and primary prey under variable levels of competition for nest holes. Competitors sharing top predators with the callers and prey of the callers interpreted alarm and non-alarm calls differently. Competitors chose preferentially alarm and non-alarm patches over control patches to breed, while prey selected alarm patches. In contrast, competition for nest sites affected habitat selection of prey species more than that of competitors of the callers. This study provides support for a changing value of alarm calls and competition for nest sites for distinct receivers related to niche overlapping among callers and eavesdroppers, therefore, calling attention to possible cascading effects by the use of information in natural communities.

A Statistical Test for Comparing Nonnested Covariance Structure Models.

ERIC Educational Resources Information Center

Levy, Roy; Hancock, Gregory R.

While statistical procedures are well known for comparing hierarchically related (nested) covariance structure models, statistical tests for comparing nonhierarchically related (nonnested) models have proven more elusive. While isolated attempts have been made, none exists within the commonly used maximum likelihood estimation framework, thereby…

Fractal multi-level organisation of human groups in a virtual world.

PubMed

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-10-06

Humans are fundamentally social. They form societies which consist of hierarchically layered nested groups of various quality, size, and structure. The anthropologic literature has classified these groups as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups, and so on. Anthropologic data show that, on average, each group consists of approximately three subgroups. However, a general understanding of the structural dependence of groups at different layers is largely missing. We extend these early findings to a very large high-precision large-scale internet-based social network data. We analyse the organisational structure of a complete, multi-relational, large social multiplex network of a human society consisting of about 400,000 odd players of an open-ended massive multiplayer online game for which we know all about their various group memberships at different layers. Remarkably, the online players' society exhibits the same type of structured hierarchical layers as found in hunter-gatherer societies. Our findings suggest that the hierarchical organisation of human society is deeply nested in human psychology.

Fractal multi-level organisation of human groups in a virtual world

PubMed Central

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-01-01

Humans are fundamentally social. They form societies which consist of hierarchically layered nested groups of various quality, size, and structure. The anthropologic literature has classified these groups as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups, and so on. Anthropologic data show that, on average, each group consists of approximately three subgroups. However, a general understanding of the structural dependence of groups at different layers is largely missing. We extend these early findings to a very large high-precision large-scale internet-based social network data. We analyse the organisational structure of a complete, multi-relational, large social multiplex network of a human society consisting of about 400,000 odd players of an open-ended massive multiplayer online game for which we know all about their various group memberships at different layers. Remarkably, the online players' society exhibits the same type of structured hierarchical layers as found in hunter-gatherer societies. Our findings suggest that the hierarchical organisation of human society is deeply nested in human psychology. PMID:25283998

Multi-scale, Hierarchically Nested Young Stellar Structures in LEGUS Galaxies

NASA Astrophysics Data System (ADS)

Thilker, David A.; LEGUS Team

2017-01-01

The study of star formation in galaxies has predominantly been limited to either young stellar clusters and HII regions, or much larger kpc-scale morphological features such as spiral arms. The HST Legacy ExtraGalactic UV Survey (LEGUS) provides a rare opportunity to link these scales in a diverse sample of nearby galaxies and obtain a more comprehensive understanding of their co-evolution for comparison against model predictions. We have utilized LEGUS stellar photometry to identify young, resolved stellar populations belonging to several age bins and then defined nested hierarchical structures as traced by these subsamples of stars. Analagous hierarchical structures were also defined using LEGUS catalogs of unresolved young stellar clusters. We will present our emerging results concerning the physical properties (e.g. area, star counts, stellar mass, star formation rate, ISM characteristics), occupancy statistics (e.g. clusters per substructure versus age and scale, parent/child demographics) and relation to overall galaxy morphology/mass for these building blocks of hierarchical star-forming structure.

Fractal multi-level organisation of human groups in a virtual world

NASA Astrophysics Data System (ADS)

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-10-01

Humans are fundamentally social. They form societies which consist of hierarchically layered nested groups of various quality, size, and structure. The anthropologic literature has classified these groups as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups, and so on. Anthropologic data show that, on average, each group consists of approximately three subgroups. However, a general understanding of the structural dependence of groups at different layers is largely missing. We extend these early findings to a very large high-precision large-scale internet-based social network data. We analyse the organisational structure of a complete, multi-relational, large social multiplex network of a human society consisting of about 400,000 odd players of an open-ended massive multiplayer online game for which we know all about their various group memberships at different layers. Remarkably, the online players' society exhibits the same type of structured hierarchical layers as found in hunter-gatherer societies. Our findings suggest that the hierarchical organisation of human society is deeply nested in human psychology.

Structure of the Epiphyte Community in a Tropical Montane Forest in SW China

PubMed Central

Zhao, Mingxu; Geekiyanage, Nalaka; Xu, Jianchu; Khin, Myo Myo; Nurdiana, Dian Ridwan; Paudel, Ekananda; Harrison, Rhett Daniel

2015-01-01

Vascular epiphytes are an understudied and particularly important component of tropical forest ecosystems. However, owing to the difficulties of access, little is known about the properties of epiphyte-host tree communities and the factors structuring them, especially in Asia. We investigated factors structuring the vascular epiphyte-host community and its network properties in a tropical montane forest in Xishuangbanna, SW China. Vascular epiphytes were surveyed in six plots located in mature forests. Six host and four micro-site environmental factors were investigated. Epiphyte diversity was strongly correlated with host size (DBH, diameter at breast height), while within hosts the highest epiphyte diversity was in the middle canopy and epiphyte diversity was significantly higher in sites with canopy soil or a moss mat than on bare bark. DBH, elevation and stem height explained 22% of the total variation in the epiphyte species assemblage among hosts, and DBH was the most important factor which alone explained 6% of the variation. Within hosts, 51% of the variation in epiphyte assemblage composition was explained by canopy position and substrate, and the most important single factor was substrate which accounted for 16% of the variation. Analysis of network properties indicated that the epiphyte host community was highly nested, with a low level of epiphyte specialization, and an almost even interaction strength between epiphytes and host trees. Together, these results indicate that large trees harbor a substantial proportion of the epiphyte community in this forest. PMID:25856457

74. East elevation of elevated Mainline structure (Section F6) looking ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

74. East elevation of elevated Mainline structure (Section F-6) looking West - along the Arborway toward the masonry bridge carrying the former New Haven R.R. tracks over the Arborway. Arborway overpass is at upper right. - Boston Elevated Railway, Elevated Mainline, Washington Street, Boston, Suffolk County, MA

Effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function and life history.

PubMed

Crino, Ondi L; Johnson, Erin E; Blickley, Jessica L; Patricelli, Gail L; Breuner, Creagh W

2013-06-01

Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species.

Persistent environmental pollutants in eggs of aplomado falcons from Northern Chihuahua, Mexico, and south Texas, USA.

PubMed

Mora, M A; Montoya, A B; Lee, M C; Macías-Duarte, A; Rodríguez-Salazar, R; Juergens, P W; Lafón-Terrazas, A

2008-01-01

The northern aplomado falcon (Falco femoralis septentrionalis) disappeared from south Texas in the 1940s. Due to great success in the release of captive-reared aplomado falcons in south Texas, there are currently more than 40 established nesting pairs in the region. Addled eggs from aplomado falcons nesting in northern Chihuahua and south Texas were analyzed to determine organochlorine (OC) and inorganic element contaminant burdens and their potential association with egg failures and effects on reproduction. Among the OCs, DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] was present at the highest concentrations (range 262-21487 ng/g wet weight) followed by polychlorinated biphenyls (PCBs, range 88-3274 ng/g ww). DDE was greater (P=0.03) in eggs from El Sueco (Chihuahua, Mexico) than in those from Matagorda Island (Texas, USA). DDE concentrations in eggs of aplomado falcons from El Sueco were elevated; however, reproductive success in the two Chihuahuan populations did not seem to be affected by DDE. DDE and metals in potential avian prey of the aplomado falcon from Matagorda Island were very low and below levels in the diet at which some negative effects might be expected. Except for mercury (Hg), metal concentrations in eggs were fairly low and were not different among locations in Chihuahua and south Texas. Hg was somewhat elevated and was greater (P<0.001) in Texas than in the Chihuahua locations. Periodic monitoring of Hg concentrations in addled eggs of aplomado falcons in south Texas is recommended to continue evaluating potential negative effects on their recovery.

Persistent environmental pollutants in eggs of aplomado falcons from Northern Chihuahua, Mexico, and South Texas, USA

USGS Publications Warehouse

Mora, M.A.; Montoya, A.B.; Lee, M.C.; Macias-Duarte, Alberto; Rodriguez-Salazar, R.; Juergens, P.W.; Lafon-Terrazas, A.

2008-01-01

The northern aplomado falcon (Falco femoralis septentrionalis) disappeared from south Texas in the 1940s. Due to great success in the release of captive-reared aplomado falcons in south Texas, there are currently more than 40 established nesting pairs in the region. Addled eggs from aplomado falcons nesting in northern Chihuahua and south Texas were analyzed to determine organochlorine (OC) and inorganic element contaminant burdens and their potential association with egg failures and effects on reproduction. Among the OCs, DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] was present at the highest concentrations (range 262-21487??ng/g wet weight) followed by polychlorinated biphenyls (PCBs, range 88-3274??ng/g ww). DDE was greater (P = 0.03) in eggs from El Sueco (Chihuahua, Mexico) than in those from Matagorda Island (Texas, USA). DDE concentrations in eggs of aplomado falcons from El Sueco were elevated; however, reproductive success in the two Chihuahuan populations did not seem to be affected by DDE. DDE and metals in potential avian prey of the aplomado falcon from Matagorda Island were very low and below levels in the diet at which some negative effects might be expected. Except for mercury (Hg), metal concentrations in eggs were fairly low and were not different among locations in Chihuahua and south Texas. Hg was somewhat elevated and was greater (P < 0.001) in Texas than in the Chihuahua locations. Periodic monitoring of Hg concentrations in addled eggs of aplomado falcons in south Texas is recommended to continue evaluating potential negative effects on their recovery. ?? 2007 Elsevier Ltd. All rights reserved.

Effects of grazing and burning on densities and habitats of breeding ducks in North Dakota

USGS Publications Warehouse

Kruse, Arnold D.; Bowen, Bonnie S.

1996-01-01

Native grassland communities controlled by public agencies become increasingly important to the maintenance of many wildlife species as privately owned grasslands are destroyed or degraded for farming, mining, and development. In turn, wildlife on publicly owned grasslands are affected by the management techniques practiced by local managers. We studied the effects of grazing and prescribed burning on upland-nesting ducks and the structure and type of vegetation from 1980 to 1988 at the Lostwood National Wildlife Refuge (NWR) in northwestern North Dakota. Mallard (Anas platyrhynchos), the most abundant species at Lostwood NWR, had lower (P < 0.05) annual nest densities on experimental and control fields in the later years than in the early years of the study. Spring burning reduced (P = 0.016) nest densities of gadwall (A. strepera). Spring grazing reduced nest densities of gadwall (P = 0.014), and blue-winged teal (A. discors, P = 0.023). Nest density of gadwall increased (P = 0.018) after spring grazing was terminated. On the summer burn/spring graze fields, blue-winged teal had lower (P = 0.010) nest densities after treatments (1987-88) than before treatments (1980-81). Nest success was high (mallard 34%, gadwall 45%, blue-winged teal 31%) but was not influenced (P 0.16) by the burning and grazing treatments. During the study, the amount of grass/brush increased, whereas the amount of brush and brush/grass decreased on control and treatment fields. During the years with burning and grazing, short vegetation increased and tall vegetation decreased. On the spring graze fields, 1 year after grazing ended the vegetation was similar to that on the control fields. The spring burn and summer burn/spring graze fields recovered more slowly. Brushy species such as western snowberry (Symphoricarpos occidentalis) provided attractive nesting habitat for many upland-nesting waterfowl species, especially mallard, gadwall, American wigeon (A. americana), and northern pintail (A. acuta). Habitat needs of additional species of wildlife that depend on grasslands may need to be considered when deciding how to manage habitat.

Building Collaborative Structures for Teachers' Autonomy and Self-Efficacy: The Mediating Role of Participative Management and Learning Culture

ERIC Educational Resources Information Center

Lu, Jiafang; Jiang, Xinhui; Yu, Huen; Li, Dongyu

2015-01-01

This study focused on the collaborative structure-building behavior of school principals and examined how such behavior affects teacher empowerment. More important, it tested the mediating effects of participative management and learning culture. By collecting nested data from 104 schools in Hong Kong and adopting multilevel structural equation…

Fine-scale genetic structure of whitebark pine (Pinus albicaulis) associations with watershed and growth form

Treesearch

Deborah L. Rogers; Constance I. Millar; Robert D. Westfall

1999-01-01

The fine-scale genetic structure of a subalpine conifer, whitebark pine (Pinus albicaulis Engelm.), was studied at nested geographic levels from watershed to adjacent stems in the eastern Sierra Nevada Range of California. A combination of several characteristics contributed to unpredicted genetic structure in this species. This includes being one of...

Localizing Tortoise Nests by Neural Networks.

PubMed

Barbuti, Roberto; Chessa, Stefano; Micheli, Alessio; Pucci, Rita

2016-01-01

The goal of this research is to recognize the nest digging activity of tortoises using a device mounted atop the tortoise carapace. The device classifies tortoise movements in order to discriminate between nest digging, and non-digging activity (specifically walking and eating). Accelerometer data was collected from devices attached to the carapace of a number of tortoises during their two-month nesting period. Our system uses an accelerometer and an activity recognition system (ARS) which is modularly structured using an artificial neural network and an output filter. For the purpose of experiment and comparison, and with the aim of minimizing the computational cost, the artificial neural network has been modelled according to three different architectures based on the input delay neural network (IDNN). We show that the ARS can achieve very high accuracy on segments of data sequences, with an extremely small neural network that can be embedded in programmable low power devices. Given that digging is typically a long activity (up to two hours), the application of ARS on data segments can be repeated over time to set up a reliable and efficient system, called Tortoise@, for digging activity recognition.

A roadmap for functional structural variants in the soybean genome

USDA-ARS?s Scientific Manuscript database

Gene structural variation (SV) has recently emerged as a key genetic mechanism underlying several important phenotypic traits in crop species. We screened a panel of 41 soybean accessions serving as parents in a soybean nested association mapping population for deletions and duplications in over 53...

Affinity for natal environments by dispersers impacts reproduction and explains geographical structure of a highly mobile bird.

PubMed

Fletcher, Robert J; Robertson, Ellen P; Wilcox, Rebecca C; Reichert, Brian E; Austin, James D; Kitchens, Wiley M

2015-09-07

Understanding dispersal and habitat selection behaviours is central to many problems in ecology, evolution and conservation. One factor often hypothesized to influence habitat selection by dispersers is the natal environment experienced by juveniles. Nonetheless, evidence for the effect of natal environment on dispersing, wild vertebrates remains limited. Using 18 years of nesting and mark-resight data across an entire North American geographical range of an endangered bird, the snail kite (Rostrhamus sociabilis), we tested for natal effects on breeding-site selection by dispersers and its consequences for reproductive success and population structure. Dispersing snail kites were more likely to nest in wetlands of the same habitat type (lacustrine or palustrine) as their natal wetland, independent of dispersal distance, but this preference declined with age and if individuals were born during droughts. Importantly, dispersing kites that bred in natal-like habitats had lower nest success and productivity than kites that did not. These behaviours help explain recently described population connectivity and spatial structure across their geographical range and reveal that assortative breeding is occurring, where birds are more likely to breed with individuals born in the same wetland type as their natal habitat. Natal environments can thus have long-term and large-scale effects on populations in nature, even in highly mobile animals. © 2015 The Author(s).

Querying Proofs

NASA Technical Reports Server (NTRS)

Aspinall, David; Denney, Ewen; Lueth, Christoph

2012-01-01

We motivate and introduce a query language PrQL designed for inspecting machine representations of proofs. PrQL natively supports hiproofs which express proof structure using hierarchical nested labelled trees. The core language presented in this paper is locally structured (first-order), with queries built using recursion and patterns over proof structure and rule names. We define the syntax and semantics of locally structured queries, demonstrate their power, and sketch some implementation experiments.

Bloodmeal Host Congregation and Landscape Structure Impact the Estimation of Female Mosquito (Diptera: Culicidae) Abundance Using Dry Ice-Baited Traps

PubMed Central

THIEMANN, TARA; NELMS, BRITTANY; REISEN, WILLIAM K.

2011-01-01

Vegetation patterns and the presence of large numbers of nesting herons and egrets significantly altered the number of host-seeking Culex tarsalis Coquillett (Diptera: Culicidae) collected at dry ice-baited traps. The numbers of females collected per trap night at traps along the ecotone of Eucalyptus stands with and without a heron colony were always greater or equal to numbers collected at traps within or under canopy. No Cx. tarsalis were collected within or under Eucaplytus canopy during the peak heron nesting season, even though these birds frequently were infected with West Nile virus and large number of engorged females could be collected at resting boxes. These data indicate a diversion of host-seeking females from traps to nesting birds reducing sampling efficiency. PMID:21661310

Osmiine bees of the genus Haetosmia (Megachilidae, Osmiini): biology, taxonomy and key to species.

PubMed

Müller, Andreas; Griswold, Terry

2017-11-29

Haetosmia is a species-poor genus of osmiine bees (Megachilidae) containing six species, which inhabit deserts and semideserts from the Canary Islands to Central Asia. Formerly considered to be restricted to the southern Palaearctic region, the genus is shown here to occur also in the northern Afrotropical region. The females of all six Haetosmia species collect pollen from the narrow-tubed flowers of Heliotropium (Boraginaceae) with the aid of specialized pollen-harvesting bristles on the proboscis. Current knowledge suggests that Haetosmia species are restricted to sandy habitats, excavate their nests in the ground and use chewed leaves to construct their urn-shaped brood cells, which are placed side by side in an enlarged chamber at the end of the nesting burrow. The taxonomic revision of Haetosmia revealed the existence of two undescribed species, H. ethiopiensis spec. nov. from eastern Africa and H. pakistaniensis spec. nov. from Pakistan. Due to clear morphological gaps and overlapping distribution area with the nominotypical subspecies, H. brachyura altera (Peters 1974) is elevated to species rank. Keys for the identification of the six Haetosmia species are provided.

Contaminant exposure of birds nesting in Green Bay, Wisconsin, USA

USGS Publications Warehouse

Custer, Thomas W.; Dummer, Paul M.; Custer, Christine M.; Franson, J. Christian; Jones, Michael

2014-01-01

In earlier studies, elevated concentrations of polychlorinated biphenyl (PCB) and p,p'-dichlorodiphenyldichloroethylene (DDE) were reported in double-crested cormorant (Phalacrocorax auritus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings collected from lower Green Bay (WI, USA) in 1994 and 1995 and black-crowned night-heron (Nycticorax nycticorax) eggs collected in 1991. Comparable samples collected in 2010 and 2011 indicated that concentrations of PCBs were 35%, 62%, 70%, and 88% lower than in the early 1990s in tree swallow eggs, tree swallow nestlings, double-crested cormorant eggs, and black-crowned night-heron eggs, respectively; concentrations of DDE were 47%, 43%, 51%, and 80% lower, respectively. These declines are consistent with regional contaminant trends in other species. Concentrations of PCBs were higher in herring gull (Larus argentatus) than in black-crowned night-heron eggs collected from Green Bay in 2010; PCB concentrations in double-crested cormorant and tree swallow eggs were intermediate. The estimated toxicity of the PCB mixture in eggs of the insectivorous tree swallow was the equal to or greater than toxicity in the 3 piscivorous bird species. A multivariate analysis indicated that the composition percentage of lower-numbered PCB congeners was greater in eggs of the insectivorous tree swallow than in eggs of the 3 piscivorous species nesting in Green Bay. Dioxin and furan concentrations and the toxicity of these chemicals were also higher in tree swallows than these other waterbird species nesting in Green Bay.

Contaminant exposure of birds nesting in Green Bay, Wisconsin, USA.

PubMed

Custer, Thomas W; Dummer, Paul M; Custer, Christine M; Franson, J Christian; Jones, Michael

2014-08-01

In earlier studies, elevated concentrations of polychlorinated biphenyl (PCB) and p,p'-dichlorodiphenyldichloroethylene (DDE) were reported in double-crested cormorant (Phalacrocorax auritus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings collected from lower Green Bay (WI, USA) in 1994 and 1995 and black-crowned night-heron (Nycticorax nycticorax) eggs collected in 1991. Comparable samples collected in 2010 and 2011 indicated that concentrations of PCBs were 35%, 62%, 70%, and 88% lower than in the early 1990s in tree swallow eggs, tree swallow nestlings, double-crested cormorant eggs, and black-crowned night-heron eggs, respectively; concentrations of DDE were 47%, 43%, 51%, and 80% lower, respectively. These declines are consistent with regional contaminant trends in other species. Concentrations of PCBs were higher in herring gull (Larus argentatus) than in black-crowned night-heron eggs collected from Green Bay in 2010; PCB concentrations in double-crested cormorant and tree swallow eggs were intermediate. The estimated toxicity of the PCB mixture in eggs of the insectivorous tree swallow was the equal to or greater than toxicity in the 3 piscivorous bird species. A multivariate analysis indicated that the composition percentage of lower-numbered PCB congeners was greater in eggs of the insectivorous tree swallow than in eggs of the 3 piscivorous species nesting in Green Bay. Dioxin and furan concentrations and the toxicity of these chemicals were also higher in tree swallows than these other waterbird species nesting in Green Bay. Published 2014 Wiley Periodicals, Inc.

The new electromagnetic tetrads, infinite tetrad nesting and the non-trivial emergence of complex numbers in real theories of gravitation

NASA Astrophysics Data System (ADS)

Garat, Alcides

How complex numbers get into play in a non-trivial way in real theories of gravitation is relevant since in a unified structure they should be able to relate in a natural way with quantum theories. For a long time this issue has been lingering on both relativistic formulations and quantum theories. We will analyze this fundamental subject under the light of new group isomorphism theorems linking local internal groups of transformations and local groups of spacetime transformations. The bridge between these two kinds of transformations is represented by new tetrads introduced previously. It is precisely through these local tetrad structures that we will provide a non-trivial answer to this old issue. These new tetrads have two fundamental building components, the skeletons and the gauge vectors. It is these constructive elements that provide the mathematical support that allows to prove group isomorphism theorems. In addition to this, we will prove a unique new property, the infinite tetrad nesting, alternating the nesting with non-Abelian tetrads in the construction of the tetrad gauge vectors. As an application we will demonstrate an alternative proof of a new group isomorphism theorem.

Mechanically enhanced nested-network hydrogels as a coating material for biomedical devices.

PubMed

Wang, Zhengmu; Zhang, Hongbin; Chu, Axel J; Jackson, John; Lin, Karen; Lim, Chinten James; Lange, Dirk; Chiao, Mu

2018-04-01

Well-organized composite formations such as hierarchical nested-network (NN) structure in bone tissue and reticular connective tissue present remarkable mechanical strength and play a crucial role in achieving physical and biological functions for living organisms. Inspired by these delicate microstructures in nature, an analogous scaffold of double network hydrogel was fabricated by creating a poly(2-hydroxyethyl methacrylate) (pHEMA) network in the porous structure of alginate hydrogels. The resulting hydrogel possessed hierarchical NN structure and showed significantly improved mechanical strength but still maintained high elasticity comparable to soft tissues due to a mutual strengthening effect between the two networks. The tough hydrogel is also self-lubricated, exhibiting a surface friction coefficient comparable with polydimethylsiloxane (PDMS) substrates lubricated by a commercial aqueous lubricant (K-Y Jelly) and other low surface friction hydrogels. Additional properties of this hydrogel include high hydrophilicity, good biocompatibility, tunable cell adhesion and bacterial resistance after incorporation of silver nanoparticles. Firm bonding of the hydrogel on silicone substrates could be achieved through facile chemical modification, thus enabling the use of this hydrogel as a versatile coating material for biomedical applications. In this study, we developed a tough hydrogel by crosslinking HEMA monomers in alginate hydrogels and forming a well-organized structure of hierarchical nested network (NN). Different from most reported stretchable alginate-based hydrogels, the NN hydrogel shows higher compressive strength but retains comparable softness to alginate counterparts. This work further demonstrated the good integration of the tough hydrogel with silicone substrates through chemical modification and micropillar structures. Other properties including surface friction, biocompatibility and bacterial resistance were investigated and the hydrogel shows a great promise as a versatile coating material for biomedical applications. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A Bayesian Approach for Analyzing Longitudinal Structural Equation Models

ERIC Educational Resources Information Center

Song, Xin-Yuan; Lu, Zhao-Hua; Hser, Yih-Ing; Lee, Sik-Yum

2011-01-01

This article considers a Bayesian approach for analyzing a longitudinal 2-level nonlinear structural equation model with covariates, and mixed continuous and ordered categorical variables. The first-level model is formulated for measures taken at each time point nested within individuals for investigating their characteristics that are dynamically…

Endogenous hypothermic response to hypoxia reduces brain injury: Implications for modeling hypoxic-ischemic encephalopathy and therapeutic hypothermia in neonatal mice.

PubMed

Reinboth, Barbara S; Köster, Christian; Abberger, Hanna; Prager, Sebastian; Bendix, Ivo; Felderhoff-Müser, Ursula; Herz, Josephine

2016-09-01

Hypothermia treatment (HT) is the only formally endorsed treatment recommended for hypoxic-ischemic encephalopathy (HIE). However, its success in protecting against brain injury is limited with a number to treat of 7-8. The identification of the target mechanisms of HIE in combination with HT will help to explain ineffective therapy outcomes but also requires stable experimental models in order to establish further neuroprotective therapies. Despite clinical and experimental indications for an endogenous thermoregulatory response to HIE, the potential effects on HIE-induced brain injury have largely been neglected in pre-clinical studies. In the present study we analyzed gray and white matter injury and neurobehavioral outcome in neonatal mice considering the endogenous thermoregulatory response during HIE combined with HT. HIE was induced in postnatal day (PND) 9 C57BL/6 mice through occlusion of the right common carotid artery followed by one hour of hypoxia. Hypoxia was performed at 8% or 10% oxygen (O2) at two different temperatures based on the nesting body core temperature. Using the model which mimics the clinical situation most closely, i.e. through maintenance of the nesting temperature during hypoxia we compared two mild HT protocols (rectal temperature difference 3°C for 4h), initiated either immediately after HIE or with delay of 2h. Injury was determined by histology, immunohistochemistry and western blot analyses at PND 16 and PND 51. Functional outcome was evaluated by Rota Rod, Elevated Plus Maze, Open Field and Novel Object Recognition testing at PND 30-PND 36 and PND 44-PND 50. We show that HIE modeling in neonatal mice is associated with a significant endogenous drop in body core temperature by 2°C resulting in profound neuroprotection, expressed by reduced neuropathological injury scores, reduced loss of neurons, axonal structures, myelin and decreased astrogliosis. Immediately applied post-hypoxic HT revealed slight advantages over a delayed onset of therapy on short- and long-term histological outcome demonstrated by reduced neuropathological injury scores and preservation of hippocampal structures. However, depending on the brain region analyzed neuroprotective effects were similar or even reduced compared to protection by endogenous cooling during HIE modeling. Moreover, long-term neurobehavioral outcome was only partially improved for motoric function (i.e. Rota Rod performance and rearing activity) while cognitive deficits (i.e. novel object recognition) remained unchanged. These findings emphasize the need to maintain the nesting temperature during the initiation of the pathological insult and highlight the urgency to develop and assess new adjuvant therapies for HT in well-defined experimental models. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Spatial variation in breeding habitat selection by Cerulean Warblers (Setophaga cerulea) throughout the Appalachian Mountains

USGS Publications Warehouse

Boves, Than J.; Buehler, David A.; Sheehan, James; Wood, Petra Bohall; Rodewald, Amanda D.; Larkin, Jeffrey L.; Keyser, Patrick D.; Newell, Felicity L.; Evans, Andrea; George, Gregory A.; Wigley, T.B.

2013-01-01

Studies of habitat selection are often of limited utility because they focus on small geographic areas, fail to examine behavior at multiple scales, or lack an assessment of the fitness consequences of habitat decisions. These limitations can hamper the identification of successful site-specific management strategies, which are urgently needed for severely declining species like Cerulean Warblers (Setophaga cerulea). We assessed how breeding habitat decisions made by Cerulean Warblers at multiple scales, and the subsequent effects of these decisions on nest survival, varied across the Appalachian Mountains. Selection for structural habitat features varied substantially among areas, particularly at the territory scale. Males within the least-forested landscapes selected microhabitat features that reflected more closed-canopy forest conditions, whereas males in highly forested landscapes favored features associated with canopy disturbance. Selection of nest-patch and nest-site attributes by females was more consistent across areas, with females selecting for increased tree size and understory cover and decreased basal area and midstory cover. Floristic preferences were similar across study areas: White Oak (Quercus alba), Cucumber-tree (Magnolia acuminata), and Sugar Maple (Acer saccharum) were preferred as nest trees, whereas red oak species (subgenus Erythrobalanus) and Red Maple (A. rubrum) were avoided. The habitat features that were related to nest survival also varied among study areas, and preferred features were negatively associated with nest survival at one area. Thus, our results indicate that large-scale spatial heterogeneity may influence local habitat-selection behavior and that it may be necessary to articulate site-specific management strategies for Cerulean Warblers.

California's Snow Gun and its implications for mass balance predictions under greenhouse warming

NASA Astrophysics Data System (ADS)

Howat, I.; Snyder, M.; Tulaczyk, S.; Sloan, L.

2003-12-01

Precipitation has received limited treatment in glacier and snowpack mass balance models, largely due to the poor resolution and confidence of precipitation predictions relative to temperature predictions derived from atmospheric models. Most snow and glacier mass balance models rely on statistical or lapse rate-based downscaling of general or regional circulation models (GCM's and RCM's), essentially decoupling sub-grid scale, orographically-driven evolution of atmospheric heat and moisture. Such models invariably predict large losses in the snow and ice volume under greenhouse warming. However, positive trends in the mass balance of glaciers in some warming maritime climates, as well as at high elevations of the Greenland Ice Sheet, suggest that increased precipitation may play an important role in snow- and glacier-climate interactions. Here, we present a half century of April snowpack data from the Sierra Nevada and Cascade mountains of California, USA. This high-density network of snow-course data indicates that a gain in winter snow accumulation at higher elevations has compensated loss in snow volume at lower elevations by over 50% and has led to glacier expansion on Mt. Shasta. These trends are concurrent with a region-wide increase in winter temperatures up to 2° C. They result from the orographic lifting and saturation of warmer, more humid air leading to increased precipitation at higher elevations. Previous studies have invoked such a "Snow Gun" effect to explain contemporaneous records of Tertiary ocean warming and rapid glacial expansion. A climatological context of the California's "snow gun" effect is elucidated by correlation between the elevation distribution of April SWE observations and the phase of the Pacific Decadal Oscillation and the El Nino Southern Oscillation, both controlling the heat and moisture delivered to the U.S. Pacific coast. The existence of a significant "Snow Gun" effect presents two challenges to snow and glacier mass balance modeling. Firstly, the link between amplification of orographic precipitation and the temporal evolution of ocean-climate oscillations indicates that prediction of future mass balance trends requires consideration of the timing and amplitude of such oscillations. Only recently have ocean-atmosphere models begun to realistically produce such temporal variability. Secondly, the steepening snow mass-balance elevation-gradient associated with the "Snow Gun" implies greater spatial variability in balance with warming. In a warming climate, orographic processes at a scale finer that the highest resolution RCM (>20km grid) become increasingly important and predictions based on lower elevations become increasingly inaccurate for higher elevations. Therefore, thermodynamic interaction between atmospheric heat, moisture and topography must be included in downscaling techniques. In order to demonstrate the importance of the thermodynamic downscaling in mass balance predictions, we nest a high-resolution (100m grid), coupled Orographic Precipitation and Surface Energy balance Model (OPSEM) into the RegC2.5 RCM (40 km grid) and compare results. We apply this nesting technique to Mt. Shasta, California, an area of high topography (~4000m) relative to its RegCM2.5 grid elevation (1289m). These models compute average April snow volume under present and doubled-present Atmospheric CO2 concentrations. While the RegCM2.5 regional model predicts an 83% decrease in April SWE, OPSEM predicts a 16% increase. These results indicate that thermodynamic interactions between the atmosphere and topography at sub- RCM grid resolution must be considered in mass balance models.

The Mica Creek Experimental Watershed: An Outdoor Laboratory for the Investigation of Hydrologic Processes in a Continental/Maritime Mountainous Environment

NASA Astrophysics Data System (ADS)

Link, T. E.; Gravelle, J.; Hubbart, J.; Warnsing, A.; Du, E.; Boll, J.; Brooks, E.; Cundy, T.

2004-12-01

Experimental catchments have proven to be extremely useful for investigations focused on fundamental hydrologic processes and on the impacts of land cover change on hydrologic regimes and water quality. Recent studies have illustrated how watershed responses to experimental treatments vary greatly between watersheds with differing physical, ecological and hydroclimatic characteristics. Meteorological and hydrological data within catchments are needed to help identify how hydrologic mechanisms may be altered by land cover alterations, and to both constrain and develop spatially-distributed physically based models. Existing instrumentation at the Mica Creek Experimental Watershed (MCEW) in northern Idaho is a fourth-order catchment that is undergoing expansion to produce a comprehensive dataset for model development and testing. The experimental catchments encompass a 28 km2 area spanning elevations from 975 to 1725 m msl. Snow processes dominate the hydrology of the catchment and climate conditions in the winter alternate between cold, dry continental and warm, moist maritime weather systems. Landcover is dominated by 80 year old second growth conifer forests, with partially cut (thinned) and clear-cut sub-catchments. Climate and precipitation data are collected at a SNOTEL site, three primary, and seven supplemental meteorological stations stratified by elevation and canopy cover. Manual snow depth measurements are recorded every 1-2 weeks during snowmelt, stratified by aspect, elevation and canopy cover. An air temperature transect spans three second-order sub-catchments to track air temperature lapse rate dynamics. Precipitation gauge arrays are installed within thinned and closed-canopy stands to track throughfall and interception loss. Nine paired and nested sub-catchments are monitored for flow, temperature, sediment, and nutrients. Hydroclimatic data are augmented by LiDAR and hyperspectral imagery for determination of canopy and topographic structure. Results will serve as a key dataset to assess how canopy conditions affect surface hydrology in complex snow-dominated catchments in the intermountain western U.S.

2. View of Mainline elevated structure, parallel to Washington Street, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. View of Mainline elevated structure, parallel to Washington Street, crossing over the Massachusetts Turnpike and the B&A R.R. tracks - looking North. - Boston Elevated Railway, Elevated Mainline, Washington Street, Boston, Suffolk County, MA

Recognition and characterization of hierarchical interstellar structure. II - Structure tree statistics

NASA Technical Reports Server (NTRS)

Houlahan, Padraig; Scalo, John

1992-01-01

A new method of image analysis is described, in which images partitioned into 'clouds' are represented by simplified skeleton images, called structure trees, that preserve the spatial relations of the component clouds while disregarding information concerning their sizes and shapes. The method can be used to discriminate between images of projected hierarchical (multiply nested) and random three-dimensional simulated collections of clouds constructed on the basis of observed interstellar properties, and even intermediate systems formed by combining random and hierarchical simulations. For a given structure type, the method can distinguish between different subclasses of models with different parameters and reliably estimate their hierarchical parameters: average number of children per parent, scale reduction factor per level of hierarchy, density contrast, and number of resolved levels. An application to a column density image of the Taurus complex constructed from IRAS data is given. Moderately strong evidence for a hierarchical structural component is found, and parameters of the hierarchy, as well as the average volume filling factor and mass efficiency of fragmentation per level of hierarchy, are estimated. The existence of nested structure contradicts models in which large molecular clouds are supposed to fragment, in a single stage, into roughly stellar-mass cores.

Impacts of initial convective structure on subsequent squall line evolution

NASA Astrophysics Data System (ADS)

Varble, A.; Morrison, H.; Zipser, E. J.

2017-12-01

A Weather Research and Forecasting simulation of the 20 May 2011 MC3E squall line using 750-m horizontal grid spacing produces wide convective regions with strongly upshear tilted convective updrafts and mesoscale bowing segments that are not produced in radar observations. Similar features occur across several different bulk microphysics schemes, despite surface observations exhibiting cold pool equivalent potential temperature drops that are similar to and pressure rises that are greater than those in the simulation. Observed rear inflow remains more elevated than simulated, partly counteracting the cold pool circulation, whereas the simulated rear inflow descends to low levels, maintaining its strength and reinforcing the cold pool circulation that overpowers the pre-squall line low level vertical wind shear. The descent and strength of the simulated rear inflow is fueled by strong latent cooling caused by large ice water contents detrained from upshear tilted convective cores that accumulate at the rear of the stratiform region. This simulated squall evolution is sensitive to model resolution, which is too coarse to resolve individual convective drafts. Nesting a 250-m horizontal grid spacing domain into the 750-m domain substantially alters the initial convective cells with reduced latent cooling, weaker convective downdrafts, and a weaker initial cold pool. As the initial convective cells develop into a squall line, the rear inflow remains more elevated in the 250-m domain with a cold pool that eventually develops to be just as strong and deeper than the one in the 750-m run. Despite this, the convective cores remain more upright in the 250-m run with the rear inflow partly counteracting the cold pool circulation, whereas the 750-m rear inflow near the surface reinforces the shallower cold pool and causes bowing in the squall line. The different structure in the 750-m run produces excessive mid-level front-to-rear detrainment that widens the convective region relative to the 250-m run and observations while continuing the cycle of excessive latent cooling and rear inflow descent at the rear of the stratiform region in a positive feedback. The causes of initial convective structure differences that produce the divergence in simulated squall line evolutions are explored.

Acrylamide and glycidamide hemoglobin adducts and epithelial ovarian cancer: a nested case-control study in non-smoking postmenopausal women from the EPIC cohort

PubMed Central

Obón-Santacana, Mireia; Lujan-Barroso, Leila; Travis, Ruth C.; Freisling, Heinz; Ferrari, Pietro; Severi, Gianluca; Baglietto, Laura; Boutron-Ruault, Marie-Christine; Fortner, Renée T.; Ose, Jennifer; Boeing, Heiner; Menéndez, Virginia; Sánchez-Cantalejo, Emilio; Chamosa, Saioa; Huerta Castaño, José María; Ardanaz, Eva; Khaw, Kay-Tee; Wareham, Nick; Merritt, Melissa A.; Gunter, Marc J.; Trichopoulou, Antonia; Papatesta, Eleni-Maria; Klinaki, Eleni; Saieva, Calogero; Tagliabue, Giovanna; Tumino, Rosario; Sacerdote, Carlotta; Mattiello, Amalia; Bueno-de-Mesquita, H.B.; Peeters, Petra H.; Onland-Moret, N. Charlotte; Idahl, Annika; Lundin, Eva; Weiderpass, Elisabete; Vesper, Hubert W.; Riboli, Elio; Duell, Eric J

2015-01-01

Background Acrylamide was classified as ‘probably carcinogenic to humans (group 2A)’ by the International Agency for Research on Cancer. Epithelial ovarian cancer (EOC) is the fourth cause of cancer mortality in women. Five epidemiological studies have evaluated the association between EOC risk and dietary acrylamide intake assessed using food frequency questionnaires, and one nested case-control study evaluated hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA) and EOC risk; the results of these studies were inconsistent. Methods A nested case-control study in non-smoking postmenopausal women (334 cases, 417 controls) was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Unconditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between HbAA, HbGA, HbAA+HbGA, and HbGA/HbAA and EOC and invasive serous EOC risk. Results No overall associations were observed between biomarkers of acrylamide exposure analyzed in quintiles and EOC risk; however, positive associations were observed between some middle quintiles of HbGA and HbAA+HbGA. Elevated but non-statistically significant ORs for serous EOC were observed for HbGA and HbAA+HbGA (ORQ5vsQ1:1.91, 95%CI:0.96-3.81 and ORQ5vsQ1:1.90, 95%CI:0.94-3.83, respectively); however, no linear dose-response trends were observed. Conclusion This EPIC nested case-control study failed to observe a clear association between biomarkers of acrylamide exposure and the risk of EOC or invasive serous EOC. Impact It is unlikely that dietary acrylamide exposure increases ovarian cancer risk; however, additional studies with larger sample size should be performed to exclude any possible association with EOC risk. PMID:26376083

Exposure to advertisement calls of reproductive competitors activates vocal-acoustic and catecholaminergic neurons in the plainfin midshipman fish, Porichthys notatus.

PubMed

Petersen, Christopher L; Timothy, Miky; Kim, D Spencer; Bhandiwad, Ashwin A; Mohr, Robert A; Sisneros, Joseph A; Forlano, Paul M

2013-01-01

While the neural circuitry and physiology of the auditory system is well studied among vertebrates, far less is known about how the auditory system interacts with other neural substrates to mediate behavioral responses to social acoustic signals. One species that has been the subject of intensive neuroethological investigation with regard to the production and perception of social acoustic signals is the plainfin midshipman fish, Porichthys notatus, in part because acoustic communication is essential to their reproductive behavior. Nesting male midshipman vocally court females by producing a long duration advertisement call. Females localize males by their advertisement call, spawn and deposit all their eggs in their mate's nest. As multiple courting males establish nests in close proximity to one another, the perception of another male's call may modulate individual calling behavior in competition for females. We tested the hypothesis that nesting males exposed to advertisement calls of other males would show elevated neural activity in auditory and vocal-acoustic brain centers as well as differential activation of catecholaminergic neurons compared to males exposed only to ambient noise. Experimental brains were then double labeled by immunofluorescence (-ir) for tyrosine hydroxylase (TH), an enzyme necessary for catecholamine synthesis, and cFos, an immediate-early gene product used as a marker for neural activation. Males exposed to other advertisement calls showed a significantly greater percentage of TH-ir cells colocalized with cFos-ir in the noradrenergic locus coeruleus and the dopaminergic periventricular posterior tuberculum, as well as increased numbers of cFos-ir neurons in several levels of the auditory and vocal-acoustic pathway. Increased activation of catecholaminergic neurons may serve to coordinate appropriate behavioral responses to male competitors. Additionally, these results implicate a role for specific catecholaminergic neuronal groups in auditory-driven social behavior in fishes, consistent with a conserved function in social acoustic behavior across vertebrates.

Critical region within 22q11.2 linked to higher rate of autism spectrum disorder.

PubMed

Clements, Caitlin C; Wenger, Tara L; Zoltowski, Alisa R; Bertollo, Jennifer R; Miller, Judith S; de Marchena, Ashley B; Mitteer, Lauren M; Carey, John C; Yerys, Benjamin E; Zackai, Elaine H; Emanuel, Beverly S; McDonald-McGinn, Donna M; Schultz, Robert T

2017-01-01

Previous studies have reported no clear critical region for medical comorbidities in children with deletions or duplications of 22q11.2. The purpose of this study was to evaluate whether individuals with small nested deletions or duplications of the LCR-A to B region of 22q11.2 show an elevated rate of autism spectrum disorder (ASD) compared to individuals with deletions or duplications that do not include this region. We recruited 46 patients with nested deletions ( n  = 33) or duplications ( n  = 13) of 22q11.2, including LCR-A to B ( n del  = 11), LCR-A to C ( n del  = 4), LCR-B to D ( n del  = 14; n dup  = 8), LCR-C to D ( n del  = 4; n dup  = 2), and smaller nested regions ( n  = 3). Parent questionnaire, record review, and, for a subset, in-person evaluation were used for ASD diagnostic classification. Rates of ASD in individuals with involvement of LCR-B to LCR-D were compared with Fisher's exact test to LCR-A to LCR-B for deletions, and to a previously published sample of LCR-A to LCR-D for duplications. The rates of medical comorbidities and psychiatric diagnoses were determined from questionnaires and chart review. We also report group mean differences on psychiatric questionnaires. Individuals with deletions involving LCR-A to B showed a 39-44% rate of ASD compared to 0% in individuals whose deletions did not involve LCR-A to B. We observed similar rates of medical comorbidities in individuals with involvement of LCR-A to B and LCR-B to D for both duplications and deletions, consistent with prior studies. Children with nested deletions of 22q11.2 may be at greater risk for autism spectrum disorder if the region includes LCR-A to LCR-B. Replication is needed.

Exposure to Advertisement Calls of Reproductive Competitors Activates Vocal-Acoustic and Catecholaminergic Neurons in the Plainfin Midshipman Fish, Porichthys notatus

PubMed Central

Petersen, Christopher L.; Timothy, Miky; Kim, D. Spencer; Bhandiwad, Ashwin A.; Mohr, Robert A.; Sisneros, Joseph A.; Forlano, Paul M.

2013-01-01

While the neural circuitry and physiology of the auditory system is well studied among vertebrates, far less is known about how the auditory system interacts with other neural substrates to mediate behavioral responses to social acoustic signals. One species that has been the subject of intensive neuroethological investigation with regard to the production and perception of social acoustic signals is the plainfin midshipman fish, Porichthys notatus, in part because acoustic communication is essential to their reproductive behavior. Nesting male midshipman vocally court females by producing a long duration advertisement call. Females localize males by their advertisement call, spawn and deposit all their eggs in their mate’s nest. As multiple courting males establish nests in close proximity to one another, the perception of another male’s call may modulate individual calling behavior in competition for females. We tested the hypothesis that nesting males exposed to advertisement calls of other males would show elevated neural activity in auditory and vocal-acoustic brain centers as well as differential activation of catecholaminergic neurons compared to males exposed only to ambient noise. Experimental brains were then double labeled by immunofluorescence (-ir) for tyrosine hydroxylase (TH), an enzyme necessary for catecholamine synthesis, and cFos, an immediate-early gene product used as a marker for neural activation. Males exposed to other advertisement calls showed a significantly greater percentage of TH-ir cells colocalized with cFos-ir in the noradrenergic locus coeruleus and the dopaminergic periventricular posterior tuberculum, as well as increased numbers of cFos-ir neurons in several levels of the auditory and vocal-acoustic pathway. Increased activation of catecholaminergic neurons may serve to coordinate appropriate behavioral responses to male competitors. Additionally, these results implicate a role for specific catecholaminergic neuronal groups in auditory-driven social behavior in fishes, consistent with a conserved function in social acoustic behavior across vertebrates. PMID:23936438

Stable occupancy by breeding hawks (Buteo spp.) over 25 years on a privately managed bunchgrass prairie in northeastern Oregon, USA

USGS Publications Warehouse

Kennedy, Patricia L.; Bartuszevige, Anne M.; Houle, Marcy; Humphrey, Ann B.; Dugger, Katie M.; Williams, John

2014-01-01

Potential for large prairie remnants to provide habitat for grassland-obligate wildlife may be compromised by nonsustainable range-management practices. In 1979–1980, high nesting densities of 3 species of hawks in the genus Buteo—Ferruginous Hawk (Buteo regalis), Red-tailed Hawk (B. jamaicensis), and Swainson's Hawk (B. swainsoni)—were documented on the Zumwalt Prairie and surrounding agricultural areas (34,361 ha) in northeastern Oregon, USA. This area has been managed primarily as livestock summer range since it was homesteaded. Unlike in other prairie remnants, land management on the Zumwalt Prairie was consistent over the past several decades; thus, we predicted that territory occupancy of these 3 species would be stable. We also predicted that territory occupancy would be positively related to local availability of nesting structures within territories. We evaluated these hypotheses using a historical dataset, current survey and habitat data, and occupancy models. In support of our predictions, territory occupancy of all 3 species has not changed over the study period of ∼25 yr, which suggests that local range-management practices are not negatively affecting these taxa. Probability of Ferruginous Hawk occupancy increased with increasing area of aspen, an important nest structure for this species in grasslands. Probability of Swainson's Hawk occupancy increased with increasing area of large shrubs, and probability of Red-tailed Hawk occupancy was weakly associated with area of conifers. In the study area, large shrubs and conifers are commonly used as nesting structures by Swainson's Hawks and Red-tailed Hawks, respectively. Availability of these woody species is changing (increases in conifers and large shrubs, and decline in aspen) throughout the west, and these changes may result in declines in Ferruginous Hawk occupancy and increases in Swainson's Hawk and Red-tailed Hawk occupancy in the future.

Nested effects models for learning signaling networks from perturbation data.

PubMed

Fröhlich, Holger; Tresch, Achim; Beissbarth, Tim

2009-04-01

Targeted gene perturbations have become a major tool to gain insight into complex cellular processes. In combination with the measurement of downstream effects via DNA microarrays, this approach can be used to gain insight into signaling pathways. Nested Effects Models were first introduced by Markowetz et al. as a probabilistic method to reverse engineer signaling cascades based on the nested structure of downstream perturbation effects. The basic framework was substantially extended later on by Fröhlich et al., Markowetz et al., and Tresch and Markowetz. In this paper, we present a review of the complete methodology with a detailed comparison of so far proposed algorithms on a qualitative and quantitative level. As an application, we present results on estimating the signaling network between 13 genes in the ER-alpha pathway of human MCF-7 breast cancer cells. Comparison with the literature shows a substantial overlap.