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1

Influence of grain size on species–habitat models  

Microsoft Academic Search

High resolution remote sensing data facilitate the use of small-scale habitat features such as trees or hedges in the analysis of species–habitat relationships. Such data potentially enable more accurate species–habitat mapping than lower resolution data. Here, for the first time, we systematically investigated this hypothesis by altering the spatial resolution from 1m up to 1000m grain size in species–habitat models

Thomas K. Gottschalk; Birgit Aue; Stefan Hotes; Klemens Ekschmitt

2011-01-01

2

Predicting Summer Site Occupancy for an Invasive Species, the Common Brushtail Possum (Trichosurus vulpecula), in an Urban Environment  

PubMed Central

Invasive species are often favoured in fragmented, highly-modified, human-dominated landscapes such as urban areas. Because successful invasive urban adapters can occupy habitat that is quite different from that in their original range, effective management programmes for invasive species in urban areas require an understanding of distribution, habitat and resource requirements at a local scale that is tailored to the fine-scale heterogeneity typical of urban landscapes. The common brushtail possum (Trichosurus vulpecula) is one of New Zealand’s most destructive invasive pest species. As brushtail possums traditionally occupy forest habitat, control in New Zealand has focussed on rural and forest habitats, and forest fragments in cities. However, as successful urban adapters, possums may be occupying a wider range of habitats. Here we use site occupancy methods to determine the distribution of brushtail possums across five distinguishable urban habitat types during summer, which is when possums have the greatest impacts on breeding birds. We collected data on possum presence/absence and habitat characteristics, including possible sources of supplementary food (fruit trees, vegetable gardens, compost heaps), and the availability of forest fragments from 150 survey locations. Predictive distribution models constructed using the programme PRESENCE revealed that while occupancy rates were highest in forest fragments, possums were still present across a large proportion of residential habitat with occupancy decreasing as housing density increased and green cover decreased. The presence of supplementary food sources was important in predicting possum occupancy, which may reflect the high nutritional value of these food types. Additionally, occupancy decreased as the proportion of forest fragment decreased, indicating the importance of forest fragments in determining possum distribution. Control operations to protect native birds from possum predation in cities should include well-vegetated residential areas; these modified habitats not only support possums but provide a source for reinvasion of fragments.

Adams, Amy L.; Dickinson, Katharine J. M.; Robertson, Bruce C.; van Heezik, Yolanda

2013-01-01

3

Chinook salmon use of spawning patches: Relative roles of habitat quality, size, and connectivity  

USGS Publications Warehouse

Declines in many native fish populations have led to reassessments of management goals and shifted priorities from consumptive uses to species preservation. As management has shifted, relevant environmental characteristics have evolved from traditional metrics that described local habitat quality to characterizations of habitat size and connectivity. Despite the implications this shift has for how habitats may be prioritized for conservation, it has been rare to assess the relative importance of these habitat components. We used an information-theoretic approach to select the best models from sets of logistic regressions that linked habitat quality, size, and connectivity to the occurrence of chinook salmon (Oncorhynchus tshawytscha) nests. Spawning distributions were censused annually from 1995 to 2004, and data were complemented with field measurements that described habitat quality in 43 suitable spawning patches across a stream network that drained 1150 km 2 in central Idaho. Results indicated that the most plausible models were dominated by measures of habitat size and connectivity, whereas habitat quality was of minor importance. Connectivity was the strongest predictor of nest occurrence, but connectivity interacted with habitat size, which became relatively more important when populations were reduced. Comparison of observed nest distributions to null model predictions confirmed that the habitat size association was driven by a biological mechanism when populations were small, but this association may have been an area-related sampling artifact at higher abundances. The implications for habitat management are that the size and connectivity of existing habitat networks should be maintained whenever possible. In situations where habitat restoration is occurring, expansion of existing areas or creation of new habitats in key areas that increase connectivity may be beneficial. Information about habitat size and connectivity also could be used to strategically prioritize areas for improvement of local habitat quality, with areas not meeting minimum thresholds being deemed inappropriate for pursuit of restoration activities. ?? 2007 by the Ecological Society of America.

Isaak, D. J.; Thurow, R. F.; Rieman, B. E.; Dunham, J. B.

2007-01-01

4

Territory size variation in the ovenbird: the role of habitat structure. [Seiurus aurocapillus  

SciTech Connect

The hypothesis that structural habitat cues are the proximate factor determining territory size was tested by examining the relationships among habitat structure, prey abundance, and intrapopulation variation in territory size in Ovenbirds (Seiurus aurocapillus). Territory size was negatively correlated with prey abundance, with territory size decreasing as prey abundance per unit area increased. In addition, there was a significant difference in prey abundance per unit area between territory sites and areas of the study site not occupied by ovenbirds. A regression of prey abundance with variables describing the habitat structure of territory sites was significant, with habitat structure accounting for 73% of the variation in prey abundance among territories. This regression analysis, in combination with an additional discriminant function analysis of habitat occupancy, suggested a gradient of habitat quality as a function of vegetation structure that is related to both habitat selection and variation in territory size. To determine the possible mechanisms responsible for the inverse relationship between prey abundance and territory size, several hypotheses were considered. A partial correlation analysis of territory size with prey abundance and predicted prey abundance supported a structural cues hypothesis, with variation in territory size being related to structural features of the habitat rather than prey abundance per se.

Smith, T.M.; Shugart, H.H.

1987-06-01

5

Effect of Group-Selection Opening Size on Breeding Bird Habitat Use in a Bottomland Forest  

SciTech Connect

Research on the effects of creating group-selection openings of various sizes on breeding birds habitat use in a bottomland hardwood forest of the Upper Coastal Plain of South Carolina. Creation of 0.5-ha group selection openings in southern bottomland forests should provide breeding habitat for some field-edge species in gaps and habitat for forest-interior species and canopy-dwelling forest-edge species between gaps provided that enough mature forest is made available.

Moorman, C.E.; D.C. Guynn, Jr.

2001-12-01

6

VARIATION IN JUVENILE COHO SALMON END-OF-SUMMER SIZE: HIERARACHICAL ANALYSIS OF HABITAT EFFECTS  

EPA Science Inventory

The size of coho salmon juveniles entering the winter has been shown to influence overwinter survival, and hence may be a useful indicator of linkages between summer habitat conditions and subsequent smolt production. We are investigating habitat-specific demographics of juvenile...

7

Effects of habitat complexity and group size on perceived predation risk in goldfish (Carassius auratus)  

Microsoft Academic Search

Habitat structural complexity can be an important factor in animal decisions such as habitat choice, patch use, and even mate choice. We investigate how the structural complexity of cover and group size affect perceived predation risk in goldfish (Carassius auratus) by measuring behaviors indicative of vigilance. Goldfish were videotaped in an aquarium while foraging on a saturated food patch near

J. Ingrum; S. E. Nordell; J. Dole

2010-01-01

8

Variation in territory size of the ovenbird (Seiurus aurocapillus): the role of habitat structure  

SciTech Connect

The concept that structural habitat cues are proximal factors for territory size is explored by examining the intrapopulation variation in territory size among ovenbirds (Seiurus aurocapillus). Initial territory size was determined during the first weeks of the breeding season and variables describing the structure of the vegetation within these territories were measured. Prey abundance within territories was monitored both within and among breeding seasons and correlated with both territory size and habitat structure. Similar data were also collected on areas of the study site not occupied by ovenbirds.

Smith, T.M.; Shugart, H.H.; West, D.C.

1982-08-01

9

Home-range Size and Habitat Used by the Northern Myotis (Myotis septentrionalis)  

USGS Publications Warehouse

We examined home range size and habitat use of nine female northern myotis (Myotis septentrionalis) within an intensively managed forest in the central Appalachians of West Virginia. Using the 95% adaptive kernel method, we calculated a mean home range of 65 ha. Northern myotis used recent diameter-limit harvests and road corridors more than expected based on availability of these habitats. Intact forest stands and more open deferment harvested stands were used less than expected based on the availability of these habitats, although intact forest stands still constituted the overall majority of habitat used. Partial timber harvests that leave a relatively closed canopy appear to promote or improve northern myotis foraging habitat in heavily forested landscapes. However, the long-term ecological impacts on bats and other biota from this silviculturally unacceptable practice are unclear.

Owen, S. F.; Menzel, M. A.; Ford, W. M.; Chapman, B. R.; Miller, K. V.; Edwards, J. W.; Wood, P. B.

2003-01-01

10

Habitat complexity does not promote coexistence in a size-structured intraguild predation system.  

PubMed

Size-dependent interactions and habitat complexity have been identified as important factors affecting the persistence of intraguild predation (IGP) systems. Habitat complexity has been suggested to promote intraguild (IG) prey and intraguild predator coexistence through weakening trophic interactions particularly the predation link. Here, we experimentally investigate the effects of habitat complexity on coexistence and invasion success of differently sized IG-predators in a size-structured IGP system consisting of the IG-predator Poecilia reticulata and a resident Heterandria formosa IG-prey population. The experiments included medium-long and long-term invasion experiments, predator-prey experiments and competition experiments to elucidate the mechanisms underlying the effect of prey refuges. Habitat complexity did not promote the coexistence of IG-predator and IG-prey, although the predation link was substantially weakened. However, the presence of habitat structure affected the invasion success of large IG-predators negatively and the invasion success of small IG-predators positively. The effect of refuges on size-dependent invasion success could be related to a major decrease in the IG-predator's capture rate and a shift in the size distribution of IG-predator juveniles. In summary, habitat complexity had two main effects: (i) the predation link was diminished, resulting in a more competition driven system and (ii) the overall competitive abilities of the two species were equalized, but coexistence was not promoted. Our results suggest that in a size-structured IGP system, individual level mechanisms may gain in importance over species level mechanisms in the presence of habitat complexity. PMID:23004014

Reichstein, Birte; Schröder, Arne; Persson, Lennart; De Roos, André M

2013-01-01

11

Habitat area and climate stability determine geographical variation in plant species range sizes  

PubMed Central

Despite being a fundamental aspect of biodiversity, little is known about what controls species range sizes. This is especially the case for hyperdiverse organisms such as plants. We use the largest botanical data set assembled to date to quantify geographical variation in range size for ? 85 000 plant species across the New World. We assess prominent hypothesised range-size controls, finding that plant range sizes are codetermined by habitat area and long- and short-term climate stability. Strong short- and long-term climate instability in large parts of North America, including past glaciations, are associated with broad-ranged species. In contrast, small habitat areas and a stable climate characterise areas with high concentrations of small-ranged species in the Andes, Central America and the Brazilian Atlantic Rainforest region. The joint roles of area and climate stability strengthen concerns over the potential effects of future climate change and habitat loss on biodiversity.

Morueta-Holme, Naia; Enquist, Brian J; McGill, Brian J; Boyle, Brad; J?rgensen, Peter M; Ott, Jeffrey E; Peet, Robert K; Simova, Irena; Sloat, Lindsey L; Thiers, Barbara; Violle, Cyrille; Wiser, Susan K; Dolins, Steven; Donoghue, John C; Kraft, Nathan J B; Regetz, Jim; Schildhauer, Mark; Spencer, Nick; Svenning, Jens-Christian

2013-01-01

12

Habitat degradation and fishing effects on the size structure of coral reef fish communities.  

PubMed

Overfishing and habitat degradation through climate change pose the greatest threats to sustainability of marine resources on coral reefs. We examined how changes in fishing pressure and benthic habitat composition influenced the size spectra of island-scale reef fish communities in Lau, Fiji. Between 2000 and 2006 fishing pressure declined in the Lau Islands due to declining human populations and reduced demand for fresh fish. At the same time, coral cover declined and fine-scale architectural complexity eroded due to coral bleaching and outbreaks of crown-of-thorns starfish, Acanthaster planci. We examined the size distribution of reef fish communities using size spectra analysis, the linearized relationship between abundance and body size class. Spatial variation in fishing pressure accounted for 31% of the variation in the slope of the size spectra in 2000, higher fishing pressure being associated with a steeper slope, which is indicative of fewer large-bodied fish and/or more small-bodied fish. Conversely, in 2006 spatial variation in habitat explained 53% of the variation in the size spectra slopes, and the relationship with fishing pressure was much weaker (approximately 12% of variation) than in 2000. Reduced cover of corals and lower structural complexity was associated with less steep size spectra slopes, primarily due to reduced abundance of fish < 20 cm. Habitat degradation will compound effects of fishing on coral reefs as increased fishing reduces large-bodied target species, while habitat loss results in fewer small-bodied juveniles and prey that replenish stocks and provide dietary resources for predatory target species. Effective management of reef resources therefore depends on both reducing fishing pressure and maintaining processes that encourage rapid recovery of coral habitat. PMID:20405798

Wilson, S K; Fisher, R; Pratchett, M S; Graham, N A J; Dulvy, N K; Turner, R A; Cakacaka, A; Polunin, N V C

2010-03-01

13

'Prudent habitat choice': a novel mechanism of size-assortative mating.  

PubMed

Assortative mating, an ubiquitous form of nonrandom mating, strongly impacts Darwinian fitness and can drive biological diversification. Despite its ecological and evolutionary importance, the behavioural processes underlying assortative mating are often unknown, and in particular, mechanisms not involving mate choice have been largely ignored so far. Here, we propose that assortative mating can arise from 'prudent habitat choice', a general mechanism that acts under natural selection, and that it can occur despite a complete mixing of phenotypes. We show that in the cichlid Eretmodus cyanostictus size-assortative mating ensues, because individuals of weaker competitive ability ignore high-quality but strongly competed habitat patches. Previous studies showed that in E. cyanostictus, size-based mate preferences are absent. By field and laboratory experiments, here we showed that (i) habitat quality and body size are correlated in this species; (ii) territories with more stone cover are preferred by both sexes in the absence of competition; and (iii) smaller fish prudently occupy vacant territories of worse quality than do larger fish. Prudent habitat choice is likely to be a widespread mechanism of assortative mating, as both preferences for and dominance-based access to high-quality habitats are generic phenomena in animals. PMID:24801110

Taborsky, B; Guyer, L; Demus, P

2014-06-01

14

How big and how close? Habitat patch size and spacing to conserve a threatened species  

EPA Science Inventory

We present results of a spatially-explicit, individual-based stochastic dispersal model (HexSim) to evaluate effects of size and spacing of patches of habitat of Northern Spotted Owls (NSO; Strix occidentalis caurina) in Pacific Northwest, USA, to help advise USDI Fish and Wildli...

15

Endothermy in African Platypleurine Cicadas: The Influence of Body Size and Habitat (Hemiptera: Cicadidae)  

Microsoft Academic Search

The platypleurine cicadas have a wide distribution acrossAfrica and southern Asia. We investigate endothermy as a thermo- regulatory strategy in 11 South African species from fivegenera, with comparisons to the lone ectothermic platypleurine we found, in an attempt to ascertain any influence that habitat and\\/or body size have on the expression of endothermy in the platypleurine cicadas. Field measurements of

Allen F. Sanborn; Martin H. Villet; Polly K. Phillips

2004-01-01

16

DIATOM SPECIES RICHNESS IN STREAMS OF THE EASTERN US: STREAM SIZE AND HABITAT EFFECTS  

EPA Science Inventory

We analyzed the relationship between benthic diatom assemblages, stream size, and habitat characteristics in 445 first through seventh order streams in the Mid-Atlantic (n=230), South Atlantic (n=61), Ohio (n=140), and Tennessee (n=14) hydrologic regions. Diatom samples were col...

17

Fish movement and habitat use depends on water body size and shape  

USGS Publications Warehouse

Home ranges are central to understanding habitat diversity, effects of fragmentation and conservation. The distance that an organism moves yields information on life history, genetics and interactions with other organisms. Present theory suggests that home range is set by body size of individuals. Here, we analyse estimates of home ranges in lakes and rivers to show that body size of fish and water body size and shape influence home range size. Using 71 studies including 66 fish species on five continents, we show that home range estimates increased with increasing water body size across water body shapes. This contrasts with past studies concluding that body size sets home range. We show that water body size was a consistently significant predictor of home range. In conjunction, body size and water body size can provide improved estimates of home range than just body size alone. As habitat patches are decreasing in size worldwide, our findings have implications for ecology, conservation and genetics of populations in fragmented ecosystems. ?? 2008 Blackwell Munksgaard.

Woolnough, D. A.; Downing, J. A.; Newton, T. J.

2009-01-01

18

Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish.  

PubMed

Whether and how habitat fragmentation and population size jointly affect adaptive genetic variation and adaptive population differentiation are largely unexplored. Owing to pronounced genetic drift, small, fragmented populations are thought to exhibit reduced adaptive genetic variation relative to large populations. Yet fragmentation is known to increase variability within and among habitats as population size decreases. Such variability might instead favour the maintenance of adaptive polymorphisms and/or generate more variability in adaptive differentiation at smaller population size. We investigated these alternative hypotheses by analysing coding-gene, single-nucleotide polymorphisms associated with different biological functions in fragmented brook trout populations of variable sizes. Putative adaptive differentiation was greater between small and large populations or among small populations than among large populations. These trends were stronger for genetic population size measures than demographic ones and were present despite pronounced drift in small populations. Our results suggest that fragmentation affects natural selection and that the changes elicited in the adaptive genetic composition and differentiation of fragmented populations vary with population size. By generating more variable evolutionary responses, the alteration of selective pressures during habitat fragmentation may affect future population persistence independently of, and perhaps long before, the effects of demographic and genetic stochasticity are manifest. PMID:25056619

Fraser, Dylan J; Debes, Paul V; Bernatchez, Louis; Hutchings, Jeffrey A

2014-09-01

19

Habitat selection by breeding waterbirds at ponds with size-structured fish populations  

NASA Astrophysics Data System (ADS)

Fish may significantly affect habitat use by birds, either as their prey or as competitors. Fish communities are often distinctly size-structured, but the consequences for waterbird assemblages remain poorly understood. We examined the effects of size structure of common carp ( Cyprinus carpio) cohorts together with other biotic and abiotic pond characteristics on the distribution of breeding waterbirds in a seminatural system of monocultured ponds, where three fish age classes were separately stocked. Fish age corresponded to a distinct fish size gradient. Fish age and total biomass, macroinvertebrate and amphibian abundance, and emergent vegetation best explained the differences in bird density between ponds. Abundance of animal prey other than fish (aquatic macroinvertebrates and larval amphibians) decreased with increasing carp age in the ponds. Densities of ducks and smaller grebes were strongly negatively associated with fish age/size gradient. The largest of the grebes, the piscivorous great crested grebe ( Podiceps cristatus), was the only species that preferred ponds with medium-sized fish and was positively associated with total fish biomass. Habitat selection by bitterns and most rallids was instead strongly influenced by the relative amount of emergent vegetation cover in the ponds. Our results show that fish size structure may be an important cue for breeding habitat choice and a factor affording an opportunity for niche diversification in avian communities.

Kloskowski, Janusz; Nieoczym, Marek; Polak, Marcin; Pitucha, Piotr

2010-07-01

20

Habitat selection by breeding waterbirds at ponds with size-structured fish populations.  

PubMed

Fish may significantly affect habitat use by birds, either as their prey or as competitors. Fish communities are often distinctly size-structured, but the consequences for waterbird assemblages remain poorly understood. We examined the effects of size structure of common carp (Cyprinus carpio) cohorts together with other biotic and abiotic pond characteristics on the distribution of breeding waterbirds in a seminatural system of monocultured ponds, where three fish age classes were separately stocked. Fish age corresponded to a distinct fish size gradient. Fish age and total biomass, macroinvertebrate and amphibian abundance, and emergent vegetation best explained the differences in bird density between ponds. Abundance of animal prey other than fish (aquatic macroinvertebrates and larval amphibians) decreased with increasing carp age in the ponds. Densities of ducks and smaller grebes were strongly negatively associated with fish age/size gradient. The largest of the grebes, the piscivorous great crested grebe (Podiceps cristatus), was the only species that preferred ponds with medium-sized fish and was positively associated with total fish biomass. Habitat selection by bitterns and most rallids was instead strongly influenced by the relative amount of emergent vegetation cover in the ponds. Our results show that fish size structure may be an important cue for breeding habitat choice and a factor affording an opportunity for niche diversification in avian communities. PMID:20532472

Kloskowski, Janusz; Nieoczym, Marek; Polak, Marcin; Pitucha, Piotr

2010-07-01

21

Patterns in estuarine macrofauna body size distributions: The role of habitat and disturbance impact  

NASA Astrophysics Data System (ADS)

Schwinghamer's (1981) habitat architecture hypothesis for body mass spectra in marine sediments predicts a single macrofauna mode in response to the bulk nature of the sediment. This proposition was examined for intertidal macrofauna from a well-studied estuarine system, using kernel density estimation to define modality and the locations of peaks and troughs. Three sedimentary environments and habitats were examined along a disturbance gradient related to eutrophication. Our results indicate that bimodality is likely to occur within the macrofauna size range, which weakens the habitat architecture model and casts doubts on the mechanisms behind other modes in benthic size spectra. The location of the modes and intervening trough were not conservative and not apparently related to sediment grain size or habitat structure, but somewhat dependent on the presence of particular species: the presence or absence of large numbers of individuals of Hydrobia ulvae and larger-bodied taxa such as Scrobicularia plana and Hediste diversicolor. Alternative competing hypotheses are explored for the observed results, including Warwick's (1984) phylogenetic explanation, but taking into consideration both species composition and disturbance impact, it seems most likely Holling's (1992) textural discontinuity hypothesis, as a measure of resilience, could be a plausible explanation.

Dolbeth, Marina; Raffaelli, Dave; Pardal, Miguel Ângelo

2014-01-01

22

Landscape selection by piping plovers has implications for measuring habitat and population size  

USGS Publications Warehouse

How breeding birds distribute in relation to landscape-scale habitat features has important implications for conservation because those features may constrain habitat suitability. Furthermore, knowledge of these associations can help build models to improve area-wide demographic estimates or to develop a sampling stratification for research and monitoring. This is particularly important for rare species that have uneven distributions across vast areas, such as the federally listed piping plover (Charadrius melodus; hereafter plover). We examined how remotely-sensed landscape features influenced the distribution of breeding plover pairs among 2-km shoreline segments during 2006–2009 at Lake Sakakawea in North Dakota, USA. We found strong associations between remotely-sensed landscape features and plover abundance and distribution (R2 = 0.65). Plovers were nearly absent from segments with bluffs (>25 m elevation increase within 250 m of shoreline). Relative plover density (pairs/ha) was markedly greater on islands (4.84 ± 1.22 SE) than on mainlands (0.85 ± 0.17 SE). Pair numbers increased with abundance of nesting habitat (unvegetated-flat areas ?^=0.28±0.08SE ). On islands, pair numbers also increased with the relative proportion of the total area that was habitat ( ?^=3.27±0.46SE ). Our model could be adapted to estimate the breeding population of plovers or to make predictions that provide a basis for stratification and design of future surveys. Knowledge of landscape features, such as bluffs, that exclude use by birds refines habitat suitability and facilitates more accurate estimates of habitat and population abundance, by decreasing the size of the sampling universe. Furthermore, techniques demonstrated here are applicable to other vast areas where birds breed in sparse or uneven densities.

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

2014-01-01

23

Integrating population size analysis into habitat suitability assessment: implications for giant panda conservation in the Minshan Mountains, China  

Microsoft Academic Search

Compared to conventional approaches, the integration of population size analysis with habitat suitability assessment on a\\u000a large scale can provide more evidence to explain the mechanisms of habitat isolation and fragmentation, and thus make regional\\u000a conservation plans. In this paper, we analyzed the habitat suitability for giant pandas in the Minshan Mountains, China, using\\u000a the ecological-niche factor analysis (ENFA) method,

Xuezhi Wang; Weihua Xu; Zhiyun Ouyang

2009-01-01

24

VARIATION IN JUVENILE COHO SALMON END-OF-SUMMER SIZE AND ABUNDANCE: HIERARCHICAL ANALYSIS OF HABITAT EFFECTS  

EPA Science Inventory

The size of coho salmon juveniles entering the winter has been shown to influence overwinter survival, and hence may be a useful indicator of linkages between summer habitat conditions and subsequent smolt production. We are investigating habitat-specific demographics of juvenile...

25

Prevalence and Genetic Characterization of Cryptosporidium Isolates from Common Brushtail Possums (Trichosurus vulpecula) Adapted to Urban Settings?  

PubMed Central

The common brushtail possum (Trichosurus vulpecula) is one of the most abundant native marsupials in urban Australia, having successfully adapted to utilize anthropogenic resources. The habituation of possums to food and shelter available in human settlements has facilitated interaction with people, pets, and zoo animals, increasing the potential for transmission of zoonotic Cryptosporidium pathogens. This study sought to examine the identity and prevalence of Cryptosporidium species occurring in possums adapted to urban settings compared to possums inhabiting remote woodlands far from urban areas and to characterize the health of the host in response to oocyst shedding. Findings indicated that both populations were shedding oocysts of the same genotype (brushtail possum 1 [BTP1]) that were genetically and morphologically distinct from zoonotic species and genotypes and most closely related to Cryptosporidium species from marsupials. The urban population was shedding an additional five Cryptosporidium isolates that were genetically distinct from BTP1 and formed a sister clade with Cryptosporidium parvum and Cryptosporidium hominis. Possums that were shedding oocysts showed no evidence of pathogenic changes, including elevated levels of white blood cells, diminished body condition (body mass divided by skeletal body length), or reduced nutritional state, suggesting a stable host-parasite relationship typical of Cryptosporidium species that are adapted to the host. Overall, Cryptosporidium occurred with a higher prevalence in possums from urban habitat (11.3%) than in possums from woodland habitat (5.6%); however, the host-specific nature of the genotypes may limit spillover infection in the urban setting. This study determined that the coexistence of possums with sympatric populations of humans, pets, and zoo animals in the urban Australian environment is unlikely to present a threat to public health safety.

Hill, Nichola J.; Deane, Elizabeth M.; Power, Michelle L.

2008-01-01

26

Estimates of minimum patch size depend on the method of estimation and the condition of the habitat.  

PubMed

Minimum patch size for a viable population can be estimated in several ways. The density-area method estimates minimum patch size as the smallest area in which no new individuals are encountered as one extends the arbitrary boundaries of a study area outward. The density-area method eliminates the assumption of no variation in density with size of habitat area that accompanies other methods, but it is untested in situations in which habitat loss has confined populations to small areas. We used a variant of the density area method to study the minimum patch size for the gopher tortoise (Gopherus polyphemus) in Florida, USA, where this keystone species is being confined to ever smaller habitat fragments. The variant was based on the premise that individuals within populations are likely to occur at unusually high densities when confined to small areas, and it estimated minimum patch size as the smallest area beyond which density plateaus. The data for our study came from detailed surveys of 38 populations of the tortoise. For all 38 populations, the areas occupied were determined empirically, and for 19 of them, duplicate surveys were undertaken about a decade apart. We found that a consistent inverse density area relationship was present over smaller areas. The minimum patch size estimated from the density-area relationship was at least 100 ha, which is substantially larger than previous estimates. The relative abundance of juveniles was inversely related to population density for sites with relatively poor habitat quality, indicating that the estimated minimum patch size could represent an extinction threshold. We concluded that a negative density area relationship may be an inevitable consequence of excessive habitat loss. We also concluded that any detrimental effects of an inverse density area relationship may be exacerbated by the deterioration in habitat quality that often accompanies habitat loss. Finally, we concluded that the value of any estimate of minimum patch size as a conservation tool is compromised by excessive habitat loss. PMID:17601133

McCoy, Earl D; Mushinsky, Henry R

2007-06-01

27

Relationship between body size and habitat complexity preference in age-0 and -1 year winter flounder Pseudopleuronectes americanus.  

PubMed

The interaction between body size, habitat complexity and interstice width on habitat preference of age-0 and -1 year Pseudopleuronectes americanus was examined using continuous remote video observation. The habitat choices of juvenile P. americanus were recorded over a 6 h period in tanks with four treatments: bare sand, sand with low complexity cobble, sand with intermediate complexity cobble and sand with high complexity cobble. Both age-0 and -1 year fish preferred cobble to bare sand. Within cobble treatments, age-0 year fish preferred intermediate complexity cobble, with a 1.59 ratio of interstitial space to body width. The largest age-1 year fish (123-130 mm standard length, L(S) ) preferred low complexity cobble. While a significant preference was not detected, medium age-1 year fish (83-88 mm L(S) ) tended to select low complexity cobble, whereas small age-1 year fish (73-82 mm L(S) ) tended to select low and intermediate cobble, with an interstitial space to body width ratio of 1.05. For medium and large age-1 year fish, there was an increased selection of low complexity cobble, corresponding to larger interstitial space to body size ratios. This study indicates that juvenile P. americanus prefer complex habitat to unstructured habitat and that this preference is mediated by a relationship between fish body size and the size of structure interstices. These results contribute to the growing body of knowledge of complex habitat selection and drivers of habitat choice in flatfishes. PMID:22747815

Pappal, A L; Rountree, R A; MacDonald, D G

2012-07-01

28

Preferred habitat and effective population size drive landscape genetic patterns in an endangered species.  

PubMed

Landscape genetics provides a framework for pinpointing environmental features that determine the important exchange of migrants among populations. These studies usually test the significance of environmental variables on gene flow, yet ignore one fundamental driver of genetic variation in small populations, effective population size, N(e). W(e) combined both approaches in evaluating genetic connectivity of a threatened ungulate, woodland caribou. We used least-cost paths to calculate matrices of resistance distance for landscape variables (preferred habitat, anthropogenic features and predation risk) and population-pairwise harmonic means of N(e), and correlated them with genetic distances, FST and D(c). Results showed that spatial configuration of preferred habitat and Ne were the two best predictors of genetic relationships. Additionally, controlling for the effect of Ne increased the strength of correlations of environmental variables with genetic distance, highlighting the significant underlying effect of Ne in modulating genetic drift and perceived spatial connectivity. We therefore have provided empirical support to emphasize preventing increased habitat loss and promoting population growth to ensure metapopulation viability. PMID:24004939

Weckworth, Byron V; Musiani, Marco; Decesare, Nicholas J; McDevitt, Allan D; Hebblewhite, Mark; Mariani, Stefano

2013-10-22

29

Design and Parametric Sizing of Deep Space Habitats Supporting NASA'S Human Space Flight Architecture Team  

NASA Technical Reports Server (NTRS)

NASA's Human Space Flight Architecture Team (HAT) is a multi-disciplinary, cross-agency study team that conducts strategic analysis of integrated development approaches for human and robotic space exploration architectures. During each analysis cycle, HAT iterates and refines the definition of design reference missions (DRMs), which inform the definition of a set of integrated capabilities required to explore multiple destinations. An important capability identified in this capability-driven approach is habitation, which is necessary for crewmembers to live and work effectively during long duration transits to and operations at exploration destinations beyond Low Earth Orbit (LEO). This capability is captured by an element referred to as the Deep Space Habitat (DSH), which provides all equipment and resources for the functions required to support crew safety, health, and work including: life support, food preparation, waste management, sleep quarters, and housekeeping.The purpose of this paper is to describe the design of the DSH capable of supporting crew during exploration missions. First, the paper describes the functionality required in a DSH to support the HAT defined exploration missions, the parameters affecting its design, and the assumptions used in the sizing of the habitat. Then, the process used for arriving at parametric sizing estimates to support additional HAT analyses is detailed. Finally, results from the HAT Cycle C DSH sizing are presented followed by a brief description of the remaining design trades and technological advancements necessary to enable the exploration habitation capability.

Toups, Larry; Simon, Matthew; Smitherman, David; Spexarth, Gary

2012-01-01

30

Movements, Home-Range Size and Habitat Selection of Mallards during Autumn Migration.  

PubMed

The mallard (Anas platyrhynchos) is a focal species in game management, epidemiology and ornithology, but comparably little research has focused on the ecology of the migration seasons. We studied habitat use, time-budgets, home-range sizes, habitat selection, and movements based on spatial data collected with GPS devices attached to wild mallards trapped at an autumn stopover site in the Northwest European flyway. Sixteen individuals (13 males, 3 females) were followed for 15-38 days in October to December 2010. Forty-nine percent (SD?=?8.4%) of the ducks' total time, and 85% of the day-time (SD?=?28.3%), was spent at sheltered reefs and bays on the coast. Two ducks used ponds, rather than coast, as day-roosts instead. Mallards spent most of the night (76% of total time, SD?=?15.8%) on wetlands, mainly on alvar steppe, or in various flooded areas (e.g. coastal meadows). Crop fields with maize were also selectively utilized. Movements between roosting and foraging areas mainly took place at dawn and dusk, and the home-ranges observed in our study are among the largest ever documented for mallards (mean ?=?6,859 ha; SD?=?5,872 ha). This study provides insights into relatively unknown aspects of mallard ecology. The fact that autumn-staging migratory mallards have a well-developed diel activity pattern tightly linked to the use of specific habitats has implications for wetland management, hunting and conservation, as well as for the epidemiology of diseases shared between wildlife and domestic animals. PMID:24971887

Bengtsson, Daniel; Avril, Alexis; Gunnarsson, Gunnar; Elmberg, Johan; Söderquist, Pär; Norevik, Gabriel; Tolf, Conny; Safi, Kamran; Fiedler, Wolfgang; Wikelski, Martin; Olsen, Björn; Waldenström, Jonas

2014-01-01

31

Movements, Home-Range Size and Habitat Selection of Mallards during Autumn Migration  

PubMed Central

The mallard (Anas platyrhynchos) is a focal species in game management, epidemiology and ornithology, but comparably little research has focused on the ecology of the migration seasons. We studied habitat use, time-budgets, home-range sizes, habitat selection, and movements based on spatial data collected with GPS devices attached to wild mallards trapped at an autumn stopover site in the Northwest European flyway. Sixteen individuals (13 males, 3 females) were followed for 15–38 days in October to December 2010. Forty-nine percent (SD?=?8.4%) of the ducks' total time, and 85% of the day-time (SD?=?28.3%), was spent at sheltered reefs and bays on the coast. Two ducks used ponds, rather than coast, as day-roosts instead. Mallards spent most of the night (76% of total time, SD?=?15.8%) on wetlands, mainly on alvar steppe, or in various flooded areas (e.g. coastal meadows). Crop fields with maize were also selectively utilized. Movements between roosting and foraging areas mainly took place at dawn and dusk, and the home-ranges observed in our study are among the largest ever documented for mallards (mean ?=?6,859 ha; SD?=?5,872 ha). This study provides insights into relatively unknown aspects of mallard ecology. The fact that autumn-staging migratory mallards have a well-developed diel activity pattern tightly linked to the use of specific habitats has implications for wetland management, hunting and conservation, as well as for the epidemiology of diseases shared between wildlife and domestic animals.

Bengtsson, Daniel; Avril, Alexis; Gunnarsson, Gunnar; Elmberg, Johan; Soderquist, Par; Norevik, Gabriel; Tolf, Conny; Safi, Kamran; Fiedler, Wolfgang; Wikelski, Martin; Olsen, Bjorn; Waldenstrom, Jonas

2014-01-01

32

Morphological variation of Aechmea distichantha (Bromeliaceae) in a Chaco forest: habitat and size-related effects.  

PubMed

Plants show different morphologies when growing in different habitats, but they also vary in their morphology with plant size. We examined differences in sun- and shade-grown plants of the bromeliad Aechmea distichantha with respect to relationships between plant size and variables related to plant architecture, biomass allocation and tank water dynamics. We selected vegetative plants from the understorey and from forest edges of a Chaco forest, encompassing the whole size range of this bromeliad. Plant biomass was positively correlated with most architectural variables and negatively correlated with most biomass allocation variables. Understorey plants were taller and had larger diameters, whereas sun plants had more leaves, larger sheath area, sheath biomass and sheath mass fraction. All tank water-related variables were positively correlated with plant biomass. Understorey plants had a greater projected leaf area, whereas sun plants had higher water content and evaporative area. Plasticity indices were higher for water-related than for allocation variables. In conclusion, there were architectural and biomass allocation differences between sun- and shade-grown plants along a size gradient, which, in turn, affected tank water-related variables. PMID:19470109

Cavallero, L; López, D; Barberis, I M

2009-05-01

33

Size Structure of Marine Soft-Bottom Macrobenthic Communities across Natural Habitat Gradients: Implications for Productivity and Ecosystem Function  

PubMed Central

Size distributions of biotic assemblages are important modifiers of productivity and function in marine sediments. We investigated the distribution of proportional organic biomass among logarithmic size classes (2?6J to 216J) in the soft-bottom macrofaunal communities of the Strait of Georgia, Salish Sea on the west coast of Canada. The study examines how size structure is influenced by 3 fundamental habitat descriptors: depth, sediment percent fines, and organic flux (modified by quality). These habitat variables are uncorrelated in this hydrographically diverse area, thus we examine their effects in combination and separately. Cluster analyses and cumulative biomass size spectra reveal clear and significant responses to each separate habitat variable. When combined, habitat factors result in three distinct assemblages: (1) communities with a high proportion of biomass in small organisms, typical of shallow areas (<10 m) with coarse sediments (<10% fines) and low accumulation of organic material (<3.0 gC/m2/yr/?15N); (2) communities with high proportion of biomass in the largest organisms found in the Strait, typical of deep, fine sediments with high modified organic flux (>3 g C/m2/yr/?15N) from the Fraser River; and (3) communities with biomass dominated by moderately large organisms, but lacking the smallest and largest size classes, typical of deep, fine sediments experiencing low modified organic flux (<3.0 gC/m2/yr/?15N). The remaining assemblages had intermediate habitat types and size structures. Sediment percent fines and flux appear to elicit threshold responses in size structure, whereas depth has the most linear influence on community size structure. The ecological implications of size structure in the Strait of Georgia relative to environmental conditions, secondary production and sediment bioturbation are discussed.

Macdonald, Tara A.; Burd, Brenda J.; van Roodselaar, Albert

2012-01-01

34

Patch size and shape influence the accuracy of mapping small habitat patches with a global positioning system.  

PubMed

Global positioning systems (GPS) are increasingly being used for habitat mapping because they provide spatially referenced data that can be used to characterize habitat structure across the landscape and document habitat change over time. We evaluated the accuracy of using a GPS for determining the size and location of habitat patches in a riverine environment. We simulated error attributable to a mapping-grade GPS receiver capable of achieving sub-meter accuracy onto discrete macrophyte bed and wood habitat patches (2 to 177 m(2)) that were digitized from an aerial photograph of the Laramie River, Wyoming, USA in a way that emulated field mapping. Patches with simulated error were compared to the original digitized patches. The accuracy in measuring habitat patches was affected most by patch size and less by patch shape and complexity. Perimeter length was consistently overestimated but was less biased for large, elongate patches with complex shapes. Patch area was slightly overestimated for small patches but was unbiased for large patches. Precision of area estimates was highest for large (>100 m(2)), elongate patches. Percent spatial overlap, a measure of the spatial accuracy of patch location, was low and variable for the smallest patches (2 to 5 m(2)). Mean percent spatial overlap was not related to patch shape but the precision of overlap was lower for small, elongate, and complex patches. Mapping habitat patches with a mapping-grade GPS can yield useful data, but research objectives will determine the acceptable amount of error and the smallest habitats that can be reliably measured. PMID:20890656

Dauwalter, Daniel C; Rahel, Frank J

2011-08-01

35

Heat Loss May Explain Bill Size Differences between Birds Occupying Different Habitats  

PubMed Central

Background Research on variation in bill morphology has focused on the role of diet. Bills have other functions, however, including a role in heat and water balance. The role of the bill in heat loss may be particularly important in birds where water is limiting. Song sparrows localized in coastal dunes and salt marsh edge (Melospiza melodia atlantica) are similar in size to, but have bills with a 17% greater surface area than, those that live in mesic habitats (M. m. melodia), a pattern shared with other coastal sparrows. We tested the hypotheses that sparrows can use their bills to dissipate “dry” heat, and that heat loss from the bill is higher in M. m. atlantica than M. m. melodia, which would indicate a role of heat loss and water conservation in selection for bill size. Methodology/Principal Findings Bill, tarsus, and body surface temperatures were measured using thermal imaging of sparrows exposed to temperatures from 15–37°C and combined with surface area and physical modeling to estimate the contribution of each body part to total heat loss. Song sparrow bills averaged 5–10°C hotter than ambient. The bill of M. m atlantica dissipated up to 33% more heat and 38% greater proportion of total heat than that of M. m. melodia. This could potentially reduce water loss requirements by approximately 7.7%. Conclusions/Significance This >30% higher heat loss in the bill of M. m. atlantica is independent of evaporative water loss and thus could play an important role in the water balance of sparrows occupying the hot and exposed dune/salt marsh environments during the summer. Heat loss capacity and water conservation could play an important role in the selection for bill size differences between bird populations and should be considered along with trophic adaptations when studying variation in bill size.

Greenberg, Russell; Cadena, Viviana; Danner, Raymond M.; Tattersall, Glenn

2012-01-01

36

Millimeter-sized marine plastics: a new pelagic habitat for microorganisms and invertebrates.  

PubMed

Millimeter-sized plastics are abundant in most marine surface waters, and known to carry fouling organisms that potentially play key roles in the fate and ecological impacts of plastic pollution. In this study we used scanning electron microscopy to characterize biodiversity of organisms on the surface of 68 small floating plastics (length range?=?1.7-24.3 mm, median?=?3.2 mm) from Australia-wide coastal and oceanic, tropical to temperate sample collections. Diatoms were the most diverse group of plastic colonizers, represented by 14 genera. We also recorded 'epiplastic' coccolithophores (7 genera), bryozoans, barnacles (Lepas spp.), a dinoflagellate (Ceratium), an isopod (Asellota), a marine worm, marine insect eggs (Halobates sp.), as well as rounded, elongated, and spiral cells putatively identified as bacteria, cyanobacteria, and fungi. Furthermore, we observed a variety of plastic surface microtextures, including pits and grooves conforming to the shape of microorganisms, suggesting that biota may play an important role in plastic degradation. This study highlights how anthropogenic millimeter-sized polymers have created a new pelagic habitat for microorganisms and invertebrates. The ecological ramifications of this phenomenon for marine organism dispersal, ocean productivity, and biotransfer of plastic-associated pollutants, remains to be elucidated. PMID:24941218

Reisser, Julia; Shaw, Jeremy; Hallegraeff, Gustaaf; Proietti, Maira; Barnes, David K A; Thums, Michele; Wilcox, Chris; Hardesty, Britta Denise; Pattiaratchi, Charitha

2014-01-01

37

Millimeter-Sized Marine Plastics: A New Pelagic Habitat for Microorganisms and Invertebrates  

PubMed Central

Millimeter-sized plastics are abundant in most marine surface waters, and known to carry fouling organisms that potentially play key roles in the fate and ecological impacts of plastic pollution. In this study we used scanning electron microscopy to characterize biodiversity of organisms on the surface of 68 small floating plastics (length range?=?1.7–24.3 mm, median?=?3.2 mm) from Australia-wide coastal and oceanic, tropical to temperate sample collections. Diatoms were the most diverse group of plastic colonizers, represented by 14 genera. We also recorded ‘epiplastic’ coccolithophores (7 genera), bryozoans, barnacles (Lepas spp.), a dinoflagellate (Ceratium), an isopod (Asellota), a marine worm, marine insect eggs (Halobates sp.), as well as rounded, elongated, and spiral cells putatively identified as bacteria, cyanobacteria, and fungi. Furthermore, we observed a variety of plastic surface microtextures, including pits and grooves conforming to the shape of microorganisms, suggesting that biota may play an important role in plastic degradation. This study highlights how anthropogenic millimeter-sized polymers have created a new pelagic habitat for microorganisms and invertebrates. The ecological ramifications of this phenomenon for marine organism dispersal, ocean productivity, and biotransfer of plastic-associated pollutants, remains to be elucidated.

Reisser, Julia; Shaw, Jeremy; Hallegraeff, Gustaaf; Proietti, Maira; Barnes, David K. A.; Thums, Michele; Wilcox, Chris; Hardesty, Britta Denise; Pattiaratchi, Charitha

2014-01-01

38

Habitat-mediated size selection in endangered Atlantic salmon fry: selectional restoration assessment  

PubMed Central

Preservation of adaptive variation is a top priority of many species restoration programs, but most restoration activities are conducted without direct knowledge of selection that might foster or impair adaptation and restoration goals. In this study, we quantified geographic variation in selection on fry size of endangered Atlantic salmon (Salmo salar) during the 6-week period immediately following stocking in the wild. We also used a model selection approach to assess whether habitat variables influence patterns of such selection. We found evidence for significant size-selection in five out of six selection trials. Interestingly, the strength and pattern of selection varied extensively among sites, and model selection suggested that this variation in phenotypic selection was related to geographic variation in the presence of large woody debris and the slope of the stream gradient. The strong selection differentials we observed should be a concern for endangered salmon restoration, whether they reflect natural processes and an opportunity to maintain adaptation, or an indicator of the potentially deleterious phenotypic consequences of hatchery practices.

Bailey, Michael M; Kinnison, Michael T

2010-01-01

39

Home Range Size, Food Habits and Habitat Use of Female Black Bears in the Central Upper Peninsula of Michigan.  

National Technical Information Service (NTIS)

Home range size, food habits, habitat use, cub production, and survival of 10 radio-collared female black bears (Ursus americanus) were determined from 512 radio locations and visual observations, analysis of 132 scats, 100 hours of close observation of a...

T. D. DeBruyn

1992-01-01

40

Habitat stress, species pool size and biotic resistance influence exotic plant richness in the Flooding Pampa grasslands  

Microsoft Academic Search

Summary 1 Theory and empirical evidence suggest that community invasibility is influenced by propagule pressure, physical stress and biotic resistance from resident species. We studied patterns of exotic and native species richness across the Flooding Pampas of Argentina, and tested for exotic richness correlates with major environmental gradients, species pool size, and native richness, among and within different grassland habitat

SUSANA B. PERELMAN; ENRIQUE J. CHANETON; WILLIAM B. BATISTA; SILVIA E. BURKART; ROLANDO J. C. LEÓN

2007-01-01

41

Size structure of testate amoebae (Arcellinida and Euglyphida) in different habitats from a lake in the upper Paraná River floodplain.  

PubMed

This study aimed to investigate the relationship between the size structure of testate amoebae in distinct habitats, i.e. plankton, aquatic macrophytes and aquatic sediment. The samples were taken from a floodplain lake of the upper Paraná River. The assumptions we strived to scrutinize were that (i) larger mean sizes of testate amoebae would be recorded in the sediment of the lake; and (ii) temporally, smaller individuals would be registered during the high water period in all habitats. The sampling was done monthly, from April 2007 to March 2008, in triplicates for each habitat. Testate amoebae were represented by individuals sized between 20 and 400 ?m. The smaller individuals predominated in plankton samples, while in the aquatic sediment the larger ones were chiefly represented. These differences were probably associated with metabolic activities, i.e. the energy needs of these unicellular organisms, in each habitat. Two-way ANOVA yielded significant differences between hydrological periods. During the high water period, the increase in rainfall and consequently in water flow, decreased the stability of the system and increased turbulence and water column circulation. Therefore, environmental stability seems to be one of the main factors driving the temporal variation in the size structure of these specific organisms. PMID:22261279

Alves, Geziele Mucio; Velho, Luiz Felipe Machado; de Morais Costa, Deise; Lansac-Tôha, Fábio Amodêo

2012-08-01

42

Estimation of effective population size and detection of a recent population decline coinciding with habitat fragmentation in a ground beetle  

Microsoft Academic Search

We assess the impact of habitat fragmentation on the effective size (Ne) of local populations of the flightless ground beetle Carabus violaceus in a small (<25 ha) and a large (>80 ha) forest fragment separated by a highway. Ne was estimated based on the temporal variation of allele frequencies at 13 microsatellite loci using two different methods. In the smaller

I. K ELLER; L. EXCOFFIER; C. R. LARGIADER

2004-01-01

43

Crayfish predation on the common pond snail (Lymnaea stagnalis): the effect of habitat complexity and snail size on foraging efficiency  

Microsoft Academic Search

Optimal foraging theory was used to explain selective foraging by the introduced signal crayfish (Pacifastacus leniusculus)\\u000a on the thin-shelled common pond snail (Lymnaea stagnalis). Crayfish predation efficiency was studied in relation to habitat\\u000a complexity and snail size. In a pool experiment (area 1.3 m2) single adult crayfish were allowed to feed on four size classes of snails for one week.

Per Nyström; Jose R. Pérez

1998-01-01

44

Patterns in the abundance and size-distribution of syngnathid fishes among habitats in a seagrass-dominated marine environment  

NASA Astrophysics Data System (ADS)

Syngnathid fishes were sampled using a 1 m wide beam trawl during the day and night in each season from summer 1996/1997 to summer 1997/1998 in five habitat types in an approximately 90 km 2 area located on the lower west coast of Australia. The seagrasses Amphibolis griffithii, Posidonia sinuosa and Posidonia coriacea and shallow unvegetated sand were all in depths of 4-9 m, while deep habitat, which comprised mainly bare sand with isolated patches of the seagrasses Heterozostera tasmanica and Halophila ovalis, occurred at depths of 12-16 m. While A. griffithii and P. sinuosa each formed dense monospecific meadows, P. coriacea occurred in sparse clumps surrounded by areas of bare sand and patches of H. tasmanica. While catches of spotted pipefish Stigmatopora argus occurred mainly in P. sinuosa and P. coriacea, individuals of this species that exceeded ca. 55 mm in snout-vent length were far more abundant in the former habitat whereas smaller fish occurred mostly in the latter. Densities of S. argus were similar in P. sinuosa and P. coriacea, but differed between seasons, and a season/habitat interaction was present. In contrast, wide-bodied pipefish Stigmatopora nigra were collected mainly in P. coriacea and deep habitat and, although the densities were greater in P. coriacea than in deep habitat, the size-distributions of this species in these habitats were similar. Notably, S. nigra was never collected in P. sinuosa. Although less abundant than the above pipefish, the long-snouted pipefish Vanacampus poecilolaemus was collected almost exclusively in P. sinuosa. Few syngnathids were collected from shallow unvegetated sand or from A. griffithii, which differed markedly in plant structure from both Posidonia species. It is suggested that these syngnathid species occupy habitats that best enable them to remain inconspicuous to predators. Both S. argus and S. nigra have green or brown colouration and mimic strap-like seagrass leaves which they grasp with prehensile tails, whereas V. poecilolaemus, which is dark coloured and lacks a prehensile tail, most likely lies among the rich detrital material that accumulates beneath the dense P. sinuosa canopy. The movement of larger-sized S. argus from the narrow-leaved P. coriacea to the relatively broad-leaved P. sinuosa may enable the adults of this species to be better camouflaged than if they had remained in the former habitat. As they grow to only approximately half the size of S. argus, S. nigra of all sizes could remain concealed in narrow-leaved seagrasses like P. coriacea and H. tasmanica. The presence of more S. nigra in P. coriacea compared with deep habitat probably reflected the greater expanse of seagrass canopy available in the former habitat, while the inability of either Stigmatopora species to mimic the short leaves of A. griffithii could help to explain their scarcity in this seagrass. The almost total absence of S. nigra and small S. argus from P. sinuosa could be due to their inability to grasp the relatively broad leaves of this seagrass or the presence in this habitat of predators that selectively predate these smaller pipefish. That very few small-sized S. argus were present in P. coriacea during winter 1997, despite the fact that males of both Stigmatopora species carried broods of young in all seasons, suggests that the reproductive output of this species and/or the survival of recruits varied during the study period.

Kendrick, A. J.; Hyndes, G. A.

2003-07-01

45

Kidney mass and relative medullary thickness of rodents in relation to habitat, body size, and phylogeny.  

PubMed

We tested the hypotheses that relative medullary thickness (RMT) and kidney mass are positively related to habitat aridity in rodents, after controlling for correlations with body mass. Body mass, mass-corrected kidney mass, mass-corrected RMT, mass-corrected maximum urine concentration, and habitat (scored on a semiquantitative scale of 1-4 to indicate increasing aridity) all showed statistically significant phylogenetic signal. Body mass varied significantly among habitats, with the main difference being that aquatic species are larger than those from other habitats. Mass-corrected RMT and urine concentration showed a significant positive correlation (N=38; conventional r=0.649, phylogenetically independent contrasts [IC] r=0.685), thus validating RMT as a comparative index of urine concentrating ability. RMT scaled with body mass to an exponent significantly less than 0 (N=141 species; conventional allometric slope=-0.145 [95% confidence interval (CI)=-0.172, -0.117], IC allometric slope=-0.132 [95% CI=-0.180, -0.083]). Kidney mass scaled to an exponent significantly less than unity (N=104 species; conventional slope=0.809 [95% CI=0.751, 0.868], IC slope=0.773 [95% CI=0.676, 0.871]). Both conventional and phylogenetic analysis indicated that RMT varied among habitats, with rodents from arid areas having the largest values of RMT. A phylogenetic analysis indicated that mass-corrected kidney mass was positively related to habitat aridity. PMID:15286910

al-Kahtani, Mohammed A; Zuleta, Carlos; Caviedes-Vidal, Enrique; Garland, Theodore

2004-01-01

46

Timing of zona pellucida formation in the tammar wallaby ( Macropus eugenii) and brushtail possum ( Trichosurus vulpecula)  

Microsoft Academic Search

The zona pellucida (ZP) is an extracellular coat that surrounds the mammalian egg, and serves as the primary recognition site for fertilizing spermatozoa. The timetable of ZP formation was examined in two marsupials, the tammar wallaby (Macropus eugenii) and the brushtail possum (Trichosurus vulpecula) using conventional histological methods, immunofluorescence and electron microscopy. Ovaries from tammar wallaby pouch young less than

K. E Mate

1998-01-01

47

Spatial variation in impacts of brushtail possums on two Loranthaceous mistletoe species  

Microsoft Academic Search

Browsing by introduced brushtail possums is linked to major declines in mistletoe abundance in New Zealand, yet in some areas mistletoes persist, apparently unaffected by the presence of possums. To determine the cause of this spatial variation in impact I investigated the abundance and condition (crown dieback and extent of possum browse cover) of two mistletoes (Alepis flavida, Peraxilla tetrapetala)

Peter J. Sweetapple

48

Hierarchical distance-sampling models to estimate population size and habitat-specific abundance of an island endemic  

USGS Publications Warehouse

Population size and habitat-specific abundance estimates are essential for conservation management. A major impediment to obtaining such estimates is that few statistical models are able to simultaneously account for both spatial variation in abundance and heterogeneity in detection probability, and still be amenable to large-scale applications. The hierarchical distance-sampling model of J. A. Royle, D. K. Dawson, and S. Bates provides a practical solution. Here, we extend this model to estimate habitat-specific abundance and rangewide population size of a bird species of management concern, the Island Scrub-Jay (Aphelocoma insularis), which occurs solely on Santa Cruz Island, California, USA. We surveyed 307 randomly selected, 300 m diameter, point locations throughout the 250-km2 island during October 2008 and April 2009. Population size was estimated to be 2267 (95% CI 1613-3007) and 1705 (1212-2369) during the fall and spring respectively, considerably lower than a previously published but statistically problematic estimate of 12 500. This large discrepancy emphasizes the importance of proper survey design and analysis for obtaining reliable information for management decisions. Jays were most abundant in low-elevation chaparral habitat; the detection function depended primarily on the percent cover of chaparral and forest within count circles. Vegetation change on the island has been dramatic in recent decades, due to release from herbivory following the eradication of feral sheep (Ovis aries) from the majority of the island in the mid-1980s. We applied best-fit fall and spring models of habitat-specific jay abundance to a vegetation map from 1985, and estimated the population size of A. insularis was 1400-1500 at that time. The 20-30% increase in the jay population suggests that the species has benefited from the recovery of native vegetation since sheep removal. Nevertheless, this jay's tiny range and small population size make it vulnerable to natural disasters and to habitat alteration related to climate change. Our results demonstrate that hierarchical distance-sampling models hold promise for estimating population size and spatial density variation at large scales. Our statistical methods have been incorporated into the R package unmarked to facilitate their use by animal ecologists, and we provide annotated code in the Supplement.

Sillett, Scott T.; Chandler, Richard B.; Royle, J. Andrew; Kéry, Marc; Morrison, Scott A.

2012-01-01

49

Habitat Size Optimization of the O'Neill - Glaser Economic Model for Space Solar Satellite Production  

NASA Technical Reports Server (NTRS)

Creating large space habitats by launching all materials from Earth is prohibitively expensive. Using space resources and space based labor to build space solar power satellites can yield extraordinary profits after a few decades. The economic viability of this program depends on the use of space resources and space labor. To maximize the return on the investment, the early use of high density bolo habitats is required. Other shapes do not allow for the small initial scale required for a quick population increase in space. This study found that 5 Man Year, or 384 person bolo high density habitats will be the most economically feasible for a program started at year 2010 and will cause a profit by year 24 of the program, put over 45,000 people into space, and create a large system of space infrastructure for the further exploration and development of space.

Curreri, Peter A.; Detweiler, Michael

2010-01-01

50

Does size matter? An investigation of habitat use across a carnivore assemblage in the Serengeti, Tanzania.  

PubMed

1. This study utilizes a unique data set covering over 19 000 georeferenced records of species presence collected between 1993 and 2008, to explore the distribution and habitat selectivity of an assemblage of 26 carnivore species in the Serengeti-Ngorongoro landscape in northern Tanzania. 2. Two species, the large-spotted genet and the bushy-tailed mongoose, were documented for the first time within this landscape. Ecological Niche Factor Analysis (ENFA) was used to examine habitat selectivity for 18 of the 26 carnivore species for which there is sufficient data. Eleven ecogeographical variables (EGVs), such as altitude and habitat type, were used for these analyses. 3. The ENFA demonstrated that species differed in their habitat selectivity, and supported the limited ecological information already available for these species, such as the golden jackals' preference for grassland and the leopards' preference for river valleys. 4. Two aggregate scores, marginality and tolerance, are generated by the ENFA, and describe each species' habitat selectivity in relation to the suite of EGVs. These scores were used to test the hypothesis that smaller species are expected to be more selective than larger species [Science, 1989, 243, 1145]. Two predictions were tested: Marginality should decrease with body mass; and tolerance should increase with body mass. Our study provided no evidence for either prediction. 5. Our results not only support previous analyses of carnivore diet breadth, but also represent a novel approach to the investigation of habitat selection across species assemblages. Our method provides a powerful tool to explore similar questions in other systems and for other taxa. PMID:20646121

Durant, Sarah M; Craft, Meggan E; Foley, Charles; Hampson, Katie; Lobora, Alex L; Msuha, Maurus; Eblate, Ernest; Bukombe, John; McHetto, John; Pettorelli, Nathalie

2010-09-01

51

Maternal influence on philopatry and space use by juvenile brushtail possums (Trichosurus vulpecula).  

PubMed

1. ?The causes of juvenile sex-biased philopatry and space use in mammals remain poorly understood, and results of previous research have been conflicting. Experimental interventions and manipulations on wild populations are rare, but can play an important role in establishing the factors governing offspring space use. 2. ?We experimentally removed mothers of independent juvenile brushtail possums from the maternal home range and examined changes in offspring space use with global positioning system collars. We examined the influence of mother absence on philopatric behaviour, and determined whether or not maternal presence affected offspring space use. 3. ?We fitted a longitudinal linear mixed effects model to demonstrate a change over time in the home range size of juveniles following experimental treatment by the removal of their mothers. When mothers were removed from the natal range, juveniles occupied significantly larger home range areas, with average increases of 175% in 95% kernel density estimates and 289% in minimum convex polygon estimates. This increase occurred within the first month following mother absence and was independent of juvenile sex. Home ranges of control juveniles did not change during the same time period. 4. ?Changes in the spatial structure of mammalian populations in response to removal of individuals have important implications for pest management. The impacts of management strategies which target particular individuals in a population may counteract conservation benefits through their effect on the space use of survivors. Studies involving experimental removals provide important information on consequences of control and also yield insights into the causes of mammalian space use, philopatric behaviours and ultimately dispersal. PMID:21155769

Blackie, Helen M; Russell, James C; Clout, Mick N

2011-03-01

52

Nonlinearity and seasonal bias in an index of brushtail possum abundance  

USGS Publications Warehouse

Introduced brushtail possums (Trichosurus vulpecula) are a widespread pest of conservation and agriculture in New Zealand, and considerable effort has been expended controlling populations to low densities. A national protocol for monitoring the abundance of possums, termed trap catch index (TCI), was adopted in 1996. The TCI requires that lines of leghold traps set at 20-m spacing are randomly located in a management area. The traps are set for 3 fine nights and checked daily, and possums are killed and traps reset. The TCI is the mean percentage of trap nights that possums were caught, corrected for sprung traps and nontarget captures, with trap line as the sampling unit. We studied I forest and I farmland area in the North Island, New Zealand, to address concerns that TCI estimates may not be readily comparable because of seasonal changes in the capture probability of possums. We located blocks of 6 trap lines at each area and randomly trapped I line in each block in 3 seasons (summer, winter, and spring) in 2000 and 2001. We developed a model to allow for variation in local population size and nightly capture probability, and fitted the model using the Bayesian analysis software BUGS. Capture probability declined with increasing abundance of possums, generating a nonlinear TCI. Capture probability in farmland was lower during spring relative to winter and summer, and to forest during summer. In the absence of a proven and cost-effective alternative, our results support the continued use of the TCI for monitoring the abundance of possums in New Zealand. Seasonal biases in the TCI should be minimized by conducting repeat sampling in the same season.

Forsyth, D.M.; Link, W.A.; Webster, R.; Nugent, G.; Warburton, B.

2005-01-01

53

SHALLOW HABITATS IN TWO RHODE ISLAND SYSTEMS: II. PATTERNS OF SIZE, STRUCTURE AND FUNCTIONAL GROUPS  

EPA Science Inventory

We are examining habitats in small estuarine coves that may be important for the development of ecological indicators of integrity. We sampled nekton in Coggeshall Cove (shallow estuarine cove) in summer 1999 and 2000 and Ninigret Pond (coastal lagoon) in summer 2000. Coggeshall ...

54

Selection based on the size of the black tie of the great tit may be reversed in urban habitats.  

PubMed

A standard approach to model how selection shapes phenotypic traits is the analysis of capture-recapture data relating trait variation to survival. Divergent selection, however, has never been analyzed by the capture-recapture approach. Most reported examples of differences between urban and nonurban animals reflect behavioral plasticity rather than divergent selection. The aim of this paper was to use a capture-recapture approach to test the hypothesis that divergent selection can also drive local adaptation in urban habitats. We focused on the size of the black breast stripe (i.e., tie width) of the great tit (Parus major), a sexual ornament used in mate choice. Urban great tits display smaller tie sizes than forest birds. Because tie size is mostly genetically determined, it could potentially respond to selection. We analyzed capture/recapture data of male great tits in Barcelona city (N = 171) and in a nearby (7 km) forest (N = 324) from 1992 to 2008 using MARK. When modelling recapture rate, we found it to be strongly influenced by tie width, so that both for urban and forest habitats, birds with smaller ties were more trap-shy and more cautious than their larger tied counterparts. When modelling survival, we found that survival prospects in forest great tits increased the larger their tie width (i.e., directional positive selection), but the reverse was found for urban birds, with individuals displaying smaller ties showing higher survival (i.e., directional negative selection). As melanin-based tie size seems to be related to personality, and both are heritable, results may be explained by cautious personalities being favored in urban environments. More importantly, our results show that divergent selection can be an important mechanism in local adaptation to urban habitats and that capture-recapture is a powerful tool to test it. PMID:25077014

Senar, Juan Carlos; Conroy, Michael J; Quesada, Javier; Mateos-Gonzalez, Fernando

2014-07-01

55

Selection based on the size of the black tie of the great tit may be reversed in urban habitats  

PubMed Central

A standard approach to model how selection shapes phenotypic traits is the analysis of capture–recapture data relating trait variation to survival. Divergent selection, however, has never been analyzed by the capture–recapture approach. Most reported examples of differences between urban and nonurban animals reflect behavioral plasticity rather than divergent selection. The aim of this paper was to use a capture–recapture approach to test the hypothesis that divergent selection can also drive local adaptation in urban habitats. We focused on the size of the black breast stripe (i.e., tie width) of the great tit (Parus major), a sexual ornament used in mate choice. Urban great tits display smaller tie sizes than forest birds. Because tie size is mostly genetically determined, it could potentially respond to selection. We analyzed capture/recapture data of male great tits in Barcelona city (N = 171) and in a nearby (7 km) forest (N = 324) from 1992 to 2008 using MARK. When modelling recapture rate, we found it to be strongly influenced by tie width, so that both for urban and forest habitats, birds with smaller ties were more trap-shy and more cautious than their larger tied counterparts. When modelling survival, we found that survival prospects in forest great tits increased the larger their tie width (i.e., directional positive selection), but the reverse was found for urban birds, with individuals displaying smaller ties showing higher survival (i.e., directional negative selection). As melanin-based tie size seems to be related to personality, and both are heritable, results may be explained by cautious personalities being favored in urban environments. More importantly, our results show that divergent selection can be an important mechanism in local adaptation to urban habitats and that capture–recapture is a powerful tool to test it.

Senar, Juan Carlos; Conroy, Michael J; Quesada, Javier; Mateos-Gonzalez, Fernando

2014-01-01

56

The effect of fertility control on the transmission of bovine tuberculosis in wild brushtail possums  

Microsoft Academic Search

AIM: To determine the effect of fertility control on the rate of transmission of bovine tuberculosis (Tb), caused by Mycobacterium bovis, in brushtail possums (Trichosurus vulpecula).METHODS: At two study sites with a history of Tb infection in the resident possum population, a sample of adult male and female possums (n=50), determined by palpation to be Tb-free, was surgically sterilised by

DSL Ramsey; JD Coleman; MC Coleman; P Horton

2006-01-01

57

Behavior-Based Assessment of the Auditory Abilities of Brushtail Possums  

ERIC Educational Resources Information Center

Brushtail possums ("Trichosurus vulpecula") were trained to press a right lever when a tone was presented (a tone-on trial) and a left lever when a tone was not presented (a tone-off trial) to gain access to food. During training the tone was set at 80 dB(A), with a frequency of 0.88 kH for 3 possums and of 4 kH for the other 2. Once accuracy was…

Osugi, Mizuho; Foster T. Mary; Temple, William; Poling, Alan

2011-01-01

58

Testing for non-randomness in sizes and habitats of West Indian lizards: choice of species pool affects conclusions from null models  

Microsoft Academic Search

Summary Several null models are proposed for testing whether size or habitat differences in West IndianAnolis lizards are greater than expected ‘by chance’. The models differ primarily in choice of the pool from which species are sampled to form random communities. Regardless of choice of pool, size differences in the Lesser Antilles are greater than null models predict; the pool

Thomas W. Schoener

1988-01-01

59

Habitat complexity and fish size affect the detection of Indo-Pacific lionfish on invaded coral reefs  

NASA Astrophysics Data System (ADS)

A standard approach to improving the accuracy of reef fish population estimates derived from underwater visual censuses (UVCs) is the application of species-specific correction factors, which assumes that a species' detectability is constant under all conditions. To test this assumption, we quantified detection rates for invasive Indo-Pacific lionfish ( Pterois volitans and P. miles), which are now a primary threat to coral reef conservation throughout the Caribbean. Estimates of lionfish population density and distribution, which are essential for managing the invasion, are currently obtained through standard UVCs. Using two conventional UVC methods, the belt transect and stationary visual census (SVC), we assessed how lionfish detection rates vary with lionfish body size and habitat complexity (measured as rugosity) on invaded continuous and patch reefs off Cape Eleuthera, the Bahamas. Belt transect and SVC surveys performed equally poorly, with both methods failing to detect the presence of lionfish in >50 % of surveys where thorough, lionfish-focussed searches yielded one or more individuals. Conventional methods underestimated lionfish biomass by ~200 %. Crucially, detection rate varied significantly with both lionfish size and reef rugosity, indicating that the application of a single correction factor across habitats and stages of invasion is unlikely to accurately characterize local populations. Applying variable correction factors that account for site-specific lionfish size and rugosity to conventional survey data increased estimates of lionfish biomass, but these remained significantly lower than actual biomass. To increase the accuracy and reliability of estimates of lionfish density and distribution, monitoring programs should use detailed area searches rather than standard visual survey methods. Our study highlights the importance of accounting for sources of spatial and temporal variation in detection to increase the accuracy of survey data from coral reef systems.

Green, S. J.; Tamburello, N.; Miller, S. E.; Akins, J. L.; Côté, I. M.

2013-06-01

60

Why are predators more sensitive to habitat size than their prey? Insights from bromeliad insect food webs.  

PubMed

Ecologists have hypothesized that the exponent of species-area power functions (z value) should increase with trophic level. The main explanation for this pattern has been that specialist predators require prior colonization of a patch by their prey, resulting in a compounding of the effects of area up trophic levels. We propose two novel explanations, neither of which assumes trophic coupling between species. First, sampling effects can result in different z values if the abundances of species differ (in mean or evenness) between trophic levels. Second, when body size increases between trophic levels, effects of body size on z values may appear as differences between trophic levels. We test these alternative explanations using invertebrate food webs in 280 bromeliads from three countries. The z value of predators was higher than that of prey. Much of the difference in z values could be explained by sampling effects but not by body size effects. When damselflies occurred in the species pool, predator z values were even higher than predicted, as damselflies avoid small, drought-prone bromeliads. In one habitat, dwarf forests, detrital biomass became decoupled from bromeliad size, which also caused large trophic differences in z values. We argue that there are often simpler explanations than trophic coupling to explain differences in z values between trophic levels. PMID:18956977

Srivastava, D S; Trzcinski, M K; Richardson, B A; Gilbert, B

2008-12-01

61

Diversification Rates Increase With Population Size and Resource Concentration in an Unstructured Habitat  

PubMed Central

Understanding the mechanisms controlling the generation and maintenance of biodiversity provides some of the planet's greatest and most pressing challenges. Variation in resource concentration, which varies widely at multiple scales, may cause biodiversity to increase, decrease, or exhibit a unimodal response and underlying mechanisms remain obscure. We established experimental cultures of long-term stationary phase (LTSP) Escherichia coli to test whether per capita heterozygosity varies with resource concentration, and, if so, whether population sizes associated with different resource concentrations contributed to these patterns. Our results provide the clearest example to date of increasing per capita heterozygosity with increasing resource concentration. Further, our experimental manipulations of population size, independent of resource concentration, provide the first unequivocal evidence that population size is one of the underlying factors controlling per capita heterozygosity along such resource gradients. Specifically, we show that cultures with higher maximum population sizes, associated with higher resource concentrations, have higher per capita heterozygosity. These experiments provide the first experimental evidence for an underappreciated factor controlling biodiversity along resource gradients—population size. This direct evidence of population size influencing diversification rates has implications for regional and global scale patterns of biodiversity.

Stevens, M. H. H.; Sanchez, M.; Lee, J.; Finkel, S. E.

2007-01-01

62

The spatial distribution and size of rook (Corvus frugilegus) breeding colonies is affected by both the distribution of foraging habitat and by intercolony competition.  

PubMed Central

Explanations for the variation in the number of nests at bird colonies have focused on competitive or habitat effects without considering potential interactions between the two. For the rook, a colonial corvid which breeds seasonally but forages around the colony throughout the year, both the amount of foraging habitat and its interaction with the number of competitors from surrounding colonies are important predictors of colony size. The distance over which these effects are strongest indicates that, for rooks, colony size may be limited outside of the breeding season when colony foraging ranges are larger and overlap to a greater extent.

Griffin, L R; Thomas, C J

2000-01-01

63

Relation of ramet size to acorn production in five oak species of xeric upland habitats in south-central Florida.  

PubMed

This study examined variation in two components of acorn production. Percentage of bearing ramets (stems) and number of acorns per bearing ramet were examined in five clonal oaks in three xeric habitats of south-central peninsular Florida in relation to ramet size within and between species and vegetative associations. Counts of acorns on two white oaks (Quercus chapmanii and Q. geminata) and three red oaks (Q. inopina, Q. laevis, and Q. myrtifolia) were conducted annually from 1969 to 1996 (except in 1991) on permanent grids in southern ridge sandhill, sand pine scrub, and scrubby flatwoods associations at the Archbold Biological Station, Florida, USA. Percentage of bearing individuals and mean number of acorns per bearing individual increased with increasing ramet size for all species across all vegetation associations. However, in Q. geminata and Q. myrtifolia, acorn production declined in the largest size class (>3.2 m), implying that larger individuals of these clonal species may become senescent. All oak species in sand pine scrub, which had a nearly closed overstory, had lower frequencies of bearing oaks and mean numbers of acorns compared with similar-sized individuals of the same species in the more open-canopied southern ridge sandhill and scrubby flatwoods associations, suggesting light limitation. The annual production of acorns by a given oak species was correlated across vegetative associations and annual acorn production of oak species was correlated for species within the same section. Intermediate-size class oaks contributed the most acorns per unit area, suggesting that stands managed with short fire-return times will provide fewer acorns to wildlife than stands managed to produce more variable distributions of oak size classes. However, our study suggests that long-unburned stands, such as those studied here, will maintain relatively constant levels of acorn production as a consequence of ramet replacement within the clones of these shrubby oaks to create a variable distribution of size classes. Of the oak species studied, Q. myrtifolia had the highest acorn production and the smallest acorns, while Q. laevis had the lowest acorn production and the largest acorns, suggesting an allocation trade-off between acorn numbers and size. PMID:21669720

Abrahamson, Warren G; Layne, James N

2002-01-01

64

Habitat structure effects on size selection of snail kites ( Rostrhamus sociabilis ) and limpkins ( Aramus guarauna ) when feeding on apple snails ( Pomacea spp.)  

NASA Astrophysics Data System (ADS)

Consumer density can influence foraging patterns such as prey-size selection, but few studies have evaluated its effects in field conditions. Here we evaluate the hypothesis that habitat structure influences forager density, and that this in turn influences the size of prey consumed by two avian predators. The sizes of two apple snail species available to, and consumed by, snail kites and limpkins were determined at sites with high and low densities of snail kite foraging perches. Sites with more perches had higher densities of snail kites, but not of limpkins. Both predators consumed prey larger than those available in the marshes, but habitat structure influenced the probability of consumption of different prey sizes. Limpkins consumed larger prey at low-density sites when compared with high-density sites, in contrast to other studies that found no size selection. Thus, limpkins can present prey-size selectivity but the presence of other predators can influence the range of prey sizes consumed. When a wider range of prey sizes is available, limpkins can select larger prey; alternatively, higher densities of other predators can result in higher foraging risk, favoring the capture of smaller, easier to handle prey. Snail kites incorporated smaller prey to their diet at low-density sites than at high-density ones, probably due to the higher costs of carrying large prey, differential age distribution, or lower foraging risks. Thus, habitat structure can influence consumer density and foraging patterns in complex ways, influencing predator-prey interactions in natural systems.

Tanaka, Marcel O.; Souza, Andréa L. T.; Módena, Érica S.

2006-07-01

65

Effects of Two Plant Secondary Metabolites, Cineole and Gallic Acid, on Nightly Feeding Patterns of the Common Brushtail Possum  

Microsoft Academic Search

We investigated effects of two plant secondary metabolites (PSMs), cineole and gallic acid, on the nightly feeding behavior of the common brushtail possum (Trichosurus vulpecula), a generalist folivore. We tested whether possums altered their feeding behavior in response to increasing levels of cineole, a dietary terpene. Possums were fed artificial diets containing three levels of cineole; zero (basal diet), medium

Natasha L. Wiggins; Clare McArthur; Stuart McLean; Rebecca Boyle

2003-01-01

66

Immunocontraception of Eastern Grey kangaroos (Macropus giganteus) with recombinant brushtail possum (Trichosurus vulpecula) ZP3 protein.  

PubMed

This study examined the potential of a recombinant marsupial zona pellucida 3 protein as a contraceptive vaccine for the Eastern Grey kangaroo, a marsupial that is locally overabundant in several regions of eastern Australia. First, a pilot study using porcine zona pellucidae (PZP) demonstrated that ZP proteins, primarily the ZP3 component of PZP, are highly immunogenic in the grey kangaroo and produce a long-lasting humoral response to a single immunisation, as found in other marsupials. Immunisation with 300 microg of a non-glycosylated recombinant brushtail possum ZP3 (recBP-ZP3) protein in complete Freund's adjuvant produced a similar, significant and sustained antibody response, and none of the immunised kangaroos (n=7) produced offspring during the following breeding season compared with four out of the six control animals. An epitope analysis of the B-cell response to recBP-ZP3 using a brushtail possum ZP3 identified numerous B-cell epitope regions clustered around the N- and C-terminal regions of the protein. Two regions of interest for further fertility vaccine development based on their immunogenicity and fertility trials and functional studies in other species were found to be immunogenic. These results suggest that immunocontraception based on targeting the ZP3 protein within the zona pellucida may be an effective strategy for fertility reduction in Eastern Grey kangaroos. PMID:19215986

Kitchener, Anne L; Harman, Amanda; Kay, David J; McCartney, Carmen A; Mate, Karen E; Rodger, John C

2009-01-01

67

Using Sodium-Chloride Tracers and Grain Size Analysis to Determine Hyporheic Permeability in Salmonid Spawning Habitat  

NASA Astrophysics Data System (ADS)

Embryonic mortality rates of salmonids are greatly affected by gravel permeability and grain size distributions within the host gravel. Typical permeability testing methods use a single standpipe to measure the permeability. For studies on the American and Feather Rivers in northern California, tracer tests were used to measure seepage velocity using a main "injection" well and several downstream monitoring wells. Bulk samples and pebble counts were used to measure grain size. Measurements were recorded at approximately 30cm depth in the gravel, where salmonid species typically lay their eggs. Sites were examined before and after stream restoration to compare subsurface habitat conditions. During each tracer test, a super-saturated NaCl solution was introduced into an "injection" standpipe with a short well screen located 30cm deep in the gravel. Identical downstream standpipes contained conductivity meters that sensed the NaCl as it passed through the gravel, causing a spike in specific conductance. Plotting the peak conductance against the arrival time allowed a seepage velocity to be measured in cm/second. Seepage velocity ranged from 0.2 - 0.7 cm/sec in restored gravel, and was less than 1.6 x 10-4 cm/sec in some un-restored areas. Grain size analysis showed that un-restored areas had an armored surface with d50 values ranging from 4-10 cm, while the subsurface showed excessive fine material supporting large grains smaller than those in the surface sample with d50 values ranging from 1.3 - 3.0 cm. Restored areas were found to contain a well sorted composition containing little to no fine material and a subsurface which closely matched the surface showing d50 values from 1.6 - 3.8 cm. Comparing results of tracer tests with grain size distributions in both restored and un-restored spawning gravels gives an indication of the relative health of a particular portion of a hyporheic river system, and the relative success of some restoration projects.

Rosenbery, J. W.; Janes, M. K.; Heffernan, J. E.; Horner, T.

2012-12-01

68

Similarity of Body Size in Queens of the Wood ant Formica aquilonia from Optimal and Sub-Optimal Habitats Indicates a Strong Heritable Component  

PubMed Central

Body size in animals is affected by both genes and the environment (e.g., the amount of food resources). In ants, body size is related to several traits in an individual's physiology and life history. For example, a large queen may increase offspring production, thus increasing her overall fitness. In this study, whether sub-optimal environmental conditions affect the body size of queens of the red wood ant, Formica aquilonia Yarrow (Hymenoptera: Formicidae). The sizes (head width in mm) of virgin queens, i.e., gynes, originating from forest interiors (resource rich) and from commercial forest clear-cuts (resource poor) were measured. No differences in the body size of the queens from the two habitats were found. In addition, the within-nest variation in queen size was similar between habitat types. The results indicate that the body size variation of F. aquilonia queens is not sensitive to environmental variation, unlike F. aquilonia workers. The lack of environmental variation in queen size in F. aquilonia may be due to a strong selection in the past to monomorphic size in this obligately polygynous (multi-queened) species.

Haatanen, Marja-Katariina; Sorvari, Jouni

2013-01-01

69

Evaluations of duck habitat and estimation of duck population sizes with a remote-sensing-based system  

USGS Publications Warehouse

During 1987-90, we used high-altitude photography, aerial videography, counts, and models to estimate sizes of breeding populations of dabbling ducks (Anatinae) and duck production and to identify duck habitat on U.S. Fish and Wildlife Service land and easements and on private land in the prairie pothole region of the United States. The study area contained about 3.1 million wetland basins (28,490 km2). Wetland area (ha per km2) was highest on service-owned land; wetland-basin density was greatest on service easements. Temporary and seasonal wetlands were underrepresented and lakes were overrepresented on service-owned land. Seventy-eight percent of all basins were less than 0.41 ha. Cropland dominated private land. Pond density decreased from 4.4/km2 in 1987 to 3.4/km2 in 1990 and pond area, from 7.2 ha/km2 to 2.7 ha/km . The density of the blue-winged teal was greatest (3.4 pairs/km2) and was followed in magnitude by those of the mallard (2.1 pairs/km2), the gadwall (1.8 pairs/km2), the northern pintail (0.8 pairs/km2), and the redhead (0.8 pairs/km2). Duck density was consistently highest on service-owned land. The decline of breeding-population sizes in 1987-90 closely corresponded to losses of pond numbers and pond area. The density of breeding pairs per pond was inversely related to pond density, suggesting that breeding ducks tended to concentrate on the remaining ponds as drought intensified. The production of recruits followed the same pattern as breeding-population sizes. We estimated that 2.5% of the ducklings hatched on service-owned land, which was 1.3% of the study area; 19.6% hatched on service easements, which were 14.2% of the study area; and 77.9% hatched on private land, which was 84.6% of the study area. Various sources of bias and sampling error and improvements to the system are discussed.

Cowardin, L. M.; Shaffer, T. L.; Arnold, P. M.

1995-01-01

70

Male Kirtland's Warblers’ patch-level response to landscape structure during periods of varying population size and habitat amounts  

Microsoft Academic Search

Forest planners must evaluate how spatiotemporal changes in habitat amount and configuration across the landscape as a result of timber management will affect species’ persistence. However, there are few long-term programs available for evaluation. We investigated the response of male Kirtland's Warbler (Dendroica kirtlandii) to 26 years of changing patch and landscape structure during a large, 26-year forestry-habitat restoration program

Deahn M. Donner; Christine A. Ribic; John R. Probst

2009-01-01

71

Field observations of the alarm response to crushed conspecifics in the freshwater snail Pomacea canaliculata : effects of habitat, vegetation, and body size  

Microsoft Academic Search

The freshwater snail Pomacea canaliculata shows alarm responses to chemical cues released from injured conspecifics, but its behavioural responses in the field are\\u000a unknown. We investigated effects of habitat (canals or paddy fields), vegetation, and body size on alarm responses in the\\u000a field. Snails responded to crushed conspecifics within 4 min by burying themselves, but the proportions of self-buried snails\\u000a were

Kahori Aizaki; Yoichi Yusa

2009-01-01

72

Habitat use and home range size of red foxes in Prince Edward Island (Canada) based on snow-tracking and radio-telemetry data  

Microsoft Academic Search

There is a lack of information regarding the ecology and behaviour of red foxes that can be used to elaborate effective management\\u000a programs for this species on Prince Edward Island (Canada). The main goal of this study was to provide baseline information\\u000a on habitat selection and home range size of red foxes on Prince Edward Island. Data were collected from

Marina Silva; Karen M. Johnson; Sheldon B. Opps

2009-01-01

73

Adenovirus precipitating antibodies in the sera of brush-tailed possums in New Zealand.  

PubMed

Sera collected from the Australian brush-tailed possum Trichosurus vulpecula in New Zealand in 1975 and 1989 were tested for the presence of antibodies to adenovirus. Of the 231 sera tested in an agar gel diffusion test, eight (3.5%) had precipitating antibodies to the group specific antigen of mammalian adenoviruses. Available data allowed 99/231 sera to be classified as being obtained from either adult (total 62) or sexually immature (total 37) possums. From the adult animals, 4/62 (6.5%) sera were positive, while no reactive sera were detected among the 37 immature animals. The results provide evidence that natural infection by an adenovirus occurs in possums in New Zealand. Further work needs to be carried out to isolate this adenovirus to enable detailed serological and epidemiological studies to be performed. A species-specific possum adenovirus could have potential in the biological control of this species. PMID:16031621

Rice, M; Wilks, C R; Pfeiffer, D; Jackson, R

1991-06-01

74

Endogenous Type D Retrovirus in a Marsupial, the Common Brushtail Possum (Trichosurus vulpecula)  

PubMed Central

We have sequenced and characterized an endogenous type D retrovirus, which we have named TvERV(D), from the genome of an Australian marsupial, the common brushtail possum (Trichosurus vulpecula). Intact TvERV(D) gag, pro, pol, and env open reading frames were detected in the possum genome. TvERV(D) was classified as a type D retrovirus, most closely related to those of Old World monkeys, New World monkeys, and mice, based on phylogenetic analyses and genetic organization. Approximately 30 TvERV(D) proviruses are present in the genomes of possums, as detected by Southern hybridization. However, variability in fragment patterns between possums was observed and suggests recent (or ongoing) retrotranspositional activity.

Baillie, Gregory J.; Wilkins, Richard J.

2001-01-01

75

Morphology of the lingual papillae in the brush-tailed rat kangaroo.  

PubMed

We examined the dorsal lingual surface of an adult brush-tailed rat kangaroo (Bettongia penicillata) by scanning electron microscopy. The filiform and fungiform papillae on the lingual apex and body consisted of a main papilla and secondary papillae. The connective tissue core of the filiform papillae on the lingual apex was cylindrical in shape with a crushed top. The connective tissue core of the filiform papillae on the lingual body had one large and several small processes. The fungiform papillae were round in shape. The connective tissue core of the fungiform papillae had several depressions on its top. The surface of the vallate papillae was rough and the papillae were surrounded by a groove and a pad. Several long conical papillae derived from the posterolateral margin of the tongue where foliate papillae have been shown to be distributed in many other animal species. The long conical papillae were very similar to those of the koala and opossum. PMID:24815106

Emura, Shoichi; Okumura, Toshihiko; Chen, Huayue

2014-01-01

76

Changes in milk carbohydrates during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia:Phalangeridae).  

PubMed

Milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (Trichosurus vulpecula). Qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. However, the late-lactation milk was unusual in that the carbohydrate was mainly lactose and its concentration remained relatively high (3.5 to 5.5%). In contrast to earlier findings on the milk of the tammar wallaby (Macropus eugenii), little or no nucleotide pyrophosphatase, beta-galactosidase and alkaline phosphatase activities were detected late in lactation. PMID:2561494

Crisp, E A; Cowan, P E; Messer, M

1989-01-01

77

Marsupial hypothalamo-neurohypophyseal hormones. The brush-tailed possum (Trichosurus vulpecula) active peptides.  

PubMed

The hypothalamo-neurohypophyseal hormones of the brush-tailed possum (Trichosurus vulpecula) have been purified through molecular sieving and paper chromatoelectrophoresis. Two peptides have been isolated, one with pressor property, the other with uterotonic activity. The pressor hormone has been identified as arginine vasopressin by amino acid composition and amino acid sequence. The oxytocin-like hormone has been characterized as mesotocin by amino acid composition. The amounts per dried neuro-intermediate gland (1.0-1.5 mg) are approximately 12 and 5 nmol, respectively. Up to now, mesotocin has only been found in non-mammalian tetrapods, particularly in reptiles. Its preservation in Australian marsupials (Macropodidae and Phalangeridae), and the replacement of vasotocin by a vasopressin-like peptide, suggests that they are transition species between reptiles and Eutheria. However, the presence of mesotocin raises the question of its role in marsupial lactation. PMID:7118406

Hurpet, D; Chauvet, M T; Chauvet, J; Acher, R

1982-04-01

78

Cortico-cortical connections of the motor cortex in the brushtailed possum (Trichosurus vulpecula).  

PubMed Central

Cortico-cortical connections of motor cortex in the marsupial brushtailed possum were traced by making injections of horseradish peroxidase (HRP) into two parts of motor cortex: the rostral agranular part which does not overlap somatosensory cortex, and the caudal part which does. Following injections in motor cortex, labelled neurons were observed on the same side of the brain within somatosensory areas 1 and 2 and in parietal cortex just caudal to S1, with most neurons in cortical Layers 2-4. Commissural connections were found in half of the experiments, with many labelled neurons in cortical Layer 5. We have compared the pattern of cortico-cortical connections in the possum with those seen in some other mammals, which appear generally similar. Images Fig. 4 Fig. 6

Joschko, M A; Sanderson, K J

1987-01-01

79

Size-related shifts in the habitat associations of young-of-the-year winter flounder (Pseudopleuronectes americanus): field observations and laboratory experiments with sediments and prey.  

PubMed

Field surveys and laboratory studies were used to determine the role of substrata in habitat selection by young-of-the year winter flounder. A synoptic field survey of winter flounder and sediments in the Navesink River-Sandy Hook Bay estuarine system in New Jersey demonstrated that winter flounder distribution was related to sediment grain size. Analysis using a generalized additive model indicated that the probability of capturing 10-49 mm SL winter flounder was high on sediments with a mean grain diameter of size near 1.0 mm. In the laboratory, sediment preferences and the burying ability of winter flounder (15-69 mm SL) were tested by exposing fish in 10-mm size groups to a choice of azoic sediments of different sediment grain sizes. Smaller individuals (<40 mm SL) preferred fine-grained sediments while larger individuals (>/=40 mm SL) preferred coarse-grained sediments. Burying ability increased with size and all flounders avoided sediments that prevented burial. Subsequent laboratory experiments revealed that the presence of live prey (Mya arenaria) can over-ride sediment choice by winter flounder (50-68 mm SL) indicating the complexity of interrelated factors in habitat choice. PMID:11245882

Phelan, B A.; Manderson, J P.; Stoner, A W.; Bejda, A J.

2001-03-15

80

Humoral immune responses in brushtail possums ( Trichosurus vulpecula) induced by bacterial ghosts expressing possum zona pellucida 3 protein  

Microsoft Academic Search

The introduced common brushtail possum (Trichosurus vulpecula) is a major pest in New Zealand and immunocontraceptive vaccines are being developed for biocontrol of possum populations, with bacterial ghosts (BGs) being evaluated as a means of oral delivery. Recombinant BGs expressing possum zona pellucida 3 protein (ZP3) as an L? membrane-anchored protein (ZP3-L?) or as an S-layer SbsA-fusion protein (MBP-SbsA-ZP3) were

Xianlan Cui; Janine A. Duckworth; Petra Lubitz; Frank C. Molinia; Christoph Haller; Werner Lubitz; Phil E. Cowan

2010-01-01

81

Vesicle-associated protein 1: a novel ovarian immunocontraceptive target in the common brushtail possum, Trichosurus vulpecula  

Microsoft Academic Search

Ovarian-based immunological research is currently restricted to proteins of the zona pellucida. This study examined the immunocontraceptive potential of a novel vesicle-associated protein, VAP1, previously isolated from the vesicle-rich hemisphere of the brushtail possum oocyte. Seven female possums were immunized against recombinant glutathione S-transferase-VAP1 fusion protein. Control animals (nZ3) received antigen-free vaccinations. Following immunization, regular blood sampling determined the level

A Nation; S Cui; L Selwood

2008-01-01

82

Long-Term Habitat Use by Mountain Gorillas ( Gorilla gorilla beringei ). 1. Consistency, Variation, and Home Range Size and Stability  

Microsoft Academic Search

Mountain gorillas are highly folivorous. Food is abundant and perennially available in much of their habitat. Still, limited research has shown that single gorilla groups heavily used areas where food biomass and quality were relatively high and where they met daily nutritional needs with relatively low foraging effort. Also, ecological factors influenced solitary males less than groups with females. Long-term

David P. Watts

1998-01-01

83

The ontogenetic scaling of bite force and head size in loggerhead sea turtles (Caretta caretta): implications for durophagy in neritic, benthic habitats.  

PubMed

Ontogenetic studies of vertebrate feeding performance can help address questions relevant to foraging ecology. Feeding morphology and performance can either limit access to food resources or open up new trophic niches in both aquatic and terrestrial systems. Loggerhead sea turtles are long-lived vertebrates with complex life histories that are marked by an ontogenetic shift from an oceanic habitat to a coastal neritic habitat, and a transition from soft oceanic prey to hard, benthic prey. Although considered durophagous and strong biters, bite performance has not been measured in loggerheads, nor has the ontogeny of bite performance been characterized. In the present study, we collected measurements of bite force in loggerhead turtles from hatchlings to adults. When subadults reach the body size at which the ontogenetic shift occurs, their crushing capability is great enough for them to consume numerous species of hard benthic prey of small sizes. As loggerheads mature and bite performance increases, larger and harder benthic prey become accessible. Loggerhead bite performance eventually surpasses the crushing capability of other durophagous carnivores, thereby potentially reducing competition for hard benthic prey. The increasing bite performance and accompanying changes in morphology of the head and jaws are likely an effective mechanism for resource partitioning and decreasing trophic competition. Simultaneous measurements of body and head size and the use of non-linear reduced major axis regression show that bite force increases with significant positive allometry relative to body size (straight carapace length, straight carapace width and mass) and head size (head width, height and length). Simple correlation showed that all recorded morphometrics were good predictors of measured bite performance, but an AICc-based weighted regression showed that body size (straight carapace width followed by straight carapace length and mass, respectively) were more likely predictors of bite force than head size morphometrics (head width and head length). PMID:22899532

Marshall, Christopher D; Guzman, Alejandra; Narazaki, Tomoko; Sato, Katsufumi; Kane, Emily A; Sterba-Boatwright, Blair D

2012-12-01

84

Creating new evolutionary pathways through bioinvasion: the population genetics of brushtail possums in New Zealand.  

PubMed

Rapid increases in global trade and human movement have created novel mixtures of organisms bringing with them the potential to rapidly accelerate the evolution of new forms. The common brushtail possum (Trichosurus vulpecula), introduced into New Zealand from Australia in the 19th century, is one such species having been sourced from multiple populations in its native range. Here, we combine microsatellite DNA- and GIS-based spatial data to show that T. vulpecula originating from at least two different Australian locations exhibit a population structure that is commensurate with their introduction history and which cannot be explained by landscape features alone. Most importantly, we identify a hybrid zone between the two subspecies which appears to function as a barrier to dispersal. When combined with previous genetic, morphological and captive studies, our data suggest that assortative mating between the two subspecies may operate at a behavioural or species recognition level rather than through fertilization, genetic incompatibility or developmental inhibition. Nevertheless, hybridization between the two subspecies of possum clearly occurs, creating the opportunity for novel genetic combinations that would not occur in their natural ranges and which is especially likely given that multiple contact zones occur in New Zealand. This discovery has implications for wildlife management in New Zealand because multiple contact zones are likely to influence the dispersal patterns of possums and because differential susceptibility to baiting with sodium fluoroacetate between possums of different origins may promote novel genetic forms. PMID:24943509

Sarre, Stephen D; Aitken, Nicola; Adamack, Aaron T; MacDonald, Anna J; Gruber, Bernd; Cowan, Phil

2014-07-01

85

High variability in the MHC class II DA beta chain of the brushtail possum (Trichosurus vulpecula).  

PubMed

The diversity of class II major histocompatibility complex (MHC) loci was investigated in the brushtail possum, an important marsupial pest species in New Zealand. Immunocontraception, a form of fertility control that generates an autoimmune response, is being developed as a population control method for the possum. Because the immune response is partly under genetic control, an understanding of immunogenetics in possum will be crucial to the development of immunocontraceptive vaccines. MHC molecules are critical in the vertebrate immune response. Class II MHC molecules bind and present exogenously derived peptides to T lymphocytes and may be important in the presentation of immunocontraceptives. We used polymerase chain reaction primers designed to amplify the peptide binding region of possum class II MHC genes to isolate sequences from 49 animals. We have previously described 19 novel alleles from the DAB locus in the possum (Holland et al., Immunogenetics 60:449-460, 2008). Here, we report on another 11 novel alleles isolated from possum DAB, making this the most diverse marsupial locus described so far. This high level of diversity indicates that DAB is an important MHC locus in the possum and will need to be taken into account in the design of immunocontraceptive vaccines. PMID:18758765

Holland, Olivia J; Cowan, Phil E; Gleeson, Dianne M; Chamley, Larry W

2008-12-01

86

Changes in milk composition during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia: Phalangeridae).  

PubMed

The milk constituents of Trichosurus vulpecula, a folivorous marsupial, showed marked quantitative and qualitative changes during the course of lactation. The milk produced in the early stages of lactation was dilute, with about 9-13% (w/w) solids during the first 3 weeks, comprising mostly carbohydrate and protein (35-40%). At 20 weeks, about three-quarters of the way through lactation, the milk was much more concentrated, about 28% solids, with lipid the predominant fraction (30-35%), after a marked decline in carbohydrate content (20-25%). Concentrations of the electrolytes sodium and potassium also underwent marked changes. The changes in milk composition of T. vulpecula during the first three-quarters of lactation were similar to those described for a range of herbivorous, insectivorous and carnivorous marsupials. In the last quarter of lactation, however, brushtail possum milk maintained a relatively stable composition, with higher levels of carbohydrate and lower levels of lipid than for other marsupials. There appears to be a uniform pattern of changes in milk composition throughout the Marsupialia over most of lactation, with family differences evident only in the latter stages. PMID:2636424

Cowan, P E

1989-01-01

87

Size and shape variation in a Lesser Antillean anole, Anolis oculatus (Sauria: Iguanidae) in relation to habitat  

Microsoft Academic Search

The anole fauna of the Lesser Antilles is depauperate in relation to that of the Greater Antilles, where complex communities characterized by adaptive specialization and convergent structure are present. Much of this adaptation is the result of changes in body size and shape, probably as a result of interspecific competition. Here we present data on variation in size and shape

ANITA MALHOTRA; ROGER S. THORPE

1997-01-01

88

Variation in hematological and serum biochemical values of the mountain brushtail possum, Trichosurus caninus Ogilby (Marsupialia: Phalangeridae).  

PubMed

Hematological and serum biochemical values were determined in a wild population of the mountain brushtail possum (Trichosurus caninus) at Cambarville, central Victoria, southeastern Australia. Animals were sampled during two-week trapping periods in June, September, and December 1992, and April 1993. Values for hemoglobin, red cell count and hematocrit were significantly higher in males than females. Total protein and mean corpuscular volume (MCV) were significantly higher in female T. caninus. Significant seasonal variations were detected for total bilirubin, alkaline phosphatase, total protein, albumin, urea, absolute eosinophils, MCV, sodium, potassium, and phosphate. PMID:8627928

Viggers, K L; Lindenmayer, D B

1996-01-01

89

Behavior-Based Assessment of the Auditory Abilities of Brushtail Possums  

PubMed Central

Brushtail possums (Trichosurus vulpecula) were trained to press a right lever when a tone was presented (a tone-on trial) and a left lever when a tone was not presented (a tone-off trial) to gain access to food. During training the tone was set at 80 dB(A), with a frequency of 0.88 kH for 3 possums and of 4 kH for the other 2. Once accuracy was over 90% correct across five consecutive sessions, a test session was conducted where the intensity of the tone was reduced by 8 dB(A) over blocks of 20 trials until accuracy over a block fell below 60%. After each test session, training sessions were reintroduced and continued until accuracy was again over 90%, when another test session was conducted. This process continued until there were at least five test sessions at that tone frequency. The same procedure was then used with frequencies of 0.20, 0.88, 2, 4, 10, 12.5, 15, 20, 30, and 35 kHz. Percentage correct and d? decreased approximately linearly for all possums as tone intensity reduced. Both sets of lines were shallowest at the higher frequencies and steepest at the lower frequencies. Hit and false alarm rates mirrored each other at high frequencies but were asymmetric at lower frequencies. Equal d? contours showed that sensitivity increased from 2 to 15 kHz and continued to be high over 20 to 35 kHz. The possums remained sensitive to the 20 to 35 kHz tones even at low intensities. The present study is the first to report the abilities of possum to detect tones over this range of frequencies and its results support the findings of a microelectrode mapping survey of possums' auditory cortex.

Osugi, Mizuho; Foster, T. Mary; Temple, William; Poling, Alan

2011-01-01

90

Feeding habits, sexual dimorphism and size at maturity of the lizard Cnemidophorus ocellifer (Spix, 1825) (Teiidae) in a reforested restinga habitat in northeastern Brazil.  

PubMed

The feeding habits, the sexual dimorphism in size and sexual maturity of the actively foraging lizard Cnemidophorusocellifer were analysed in an area of a reforested Restinga habitat located in the municipality of Mataraca, along the northern-most coast of Paraíba State, Brazil. Seventy-five specimens of C. ocellifer were examined (46 males and 29A females). Of this total, only 23 specimens had prey in their stomachs. The most frequent prey consumed items were orthopterans (50%), coleopterans (23.9%) and arachnids (10.9%); termites and insect larvae were less consumed (both with 2.2%). There were no significant differences observed between the numbers of prey consumed by either males or females. There were significant differences in SVL (snout-vent length) between the sexes, with males attaining larger SVL values. When the influence of SVL was removed from the analyses, sexual dimorphism in the form was still reflected in the head size of these lizards. Sexual maturity in females and males was attained with SVL of 42.2 and 49.0 mm respectively. Although no significant difference was observed between the SVL of the females and the number of eggs produced, there was a clear tendency for larger females to produce more eggs. The low structural complexity of the vegetation and the poor soil quality in the reforested restinga area examined does not furnish favourable habitat for insect and termite larvae, contributing to the marked differences in the diet of the population of C. ocellifer observed in the present study in relation to the diet of their conspecifics in undisturbed areas of restinga, cerrado and caatinga. PMID:20552149

Santana, G G; Vasconcellos, A; Gadelha, Y E A; Vieira, W L S; Almeida, W O; Nóbrega, R P; Alves, R R N

2010-05-01

91

A spatial decision support system to identify species-specific critical habitats based on size and accessibility using US GAP data  

Microsoft Academic Search

The Gap Analysis Program (GAP) is a nationwide effort to find areas of suitable habitat in the US, which if protected from habitat degradation, may help to preserve the native animal and plant biodiversity. In recent years, the GAP protocols used to analyze habitat data have become more scale and species dependent. This research describes the creation of a Spatial

B. D. Larson; Raja R. Sengupta

2004-01-01

92

Detroit River habitat inventory  

USGS Publications Warehouse

This inventory complements a previous survey of habitat in Ontario waters of the Detroit River (OMNR,1993). It is a starting point for balanced and sustained use of the river for natural resource conservation and economic development. The objectives of the inventory were to: (1) locate candidate sites for protection and restoration of fish and wildlife habitat in Michigan waters of the Detroit River; (2) describe the ownership and size of each site, as well as its potential for habitat protection and restoration; and (3) subjectively assess the extent to which existing habitat along the river is productive of fish and wildlife and protected from land uses that have degraded or destroyed such habitat.

Manny, Bruce A.

2003-01-01

93

Digestion and metabolism of high-tannin Eucalyptus foliage by the brushtail possum (Trichosurus vulpecula) (Marsupialia: Phalangeridae).  

PubMed

The digestion and metabolism of Eucalyptus melliodora foliage was studied in captive brushtail possums (Trichosurus vulpecula). The foliage was low in nitrogen and silica but high in lignified fibre and phenolics compared with diets consumed by most other herbivores. The high lignin content was suggested as the main cause of the low digestibility of E. melliodora cell walls (24%); microscopic observations of plant fragments in the caecum and faeces revealed few bacteria attached to lignified tissues. The conversion of digestible energy (0.34 MJ X kg-0.75 X d-1) to metabolizable energy (0.26 MJ X kg-0.75 X d-1) was low compared to most other herbivores, probably because of excretion of metabolites of leaf essential oils and phenolics in the urine. When the inhibitory effect of leaf tannins on fibre digestion was blocked by supplementing the animals with polyethylene glycol (PEG), intake of dry matter, metabolizable energy and digestible fibre increased. These effects were attributed to the reversal by PEG of tannin-microbial enzyme complexes. It was concluded that the gut-filling effect of a bulk of indigestible fibre is a major reason why the brushtail possum does not feed exclusively on Eucalyptus foliage in the wild. PMID:3571567

Foley, W J; Hume, I D

1987-01-01

94

Soil aggregates as habitats for different microbial functional communities: Impact of different aggregate sizes and land-use  

NASA Astrophysics Data System (ADS)

Soil is a complex environment containing a huge diversity of microhabitats. This diversity of microhabitats can be taken into consideration when studying soil microbial communities by investigating soil aggregates as specific soil compartments. However, there is still an intense debate about the potential role of soil aggregates in structuring microbial communities. Thus, the aim of this study was to investigate the geochemical conditions and abundance of microbial communities among soil aggregates. Four different field sites with contrasting land-use (e.g. grassland, cropland, forest) were sampled from Critical Zone Observatory Fuchsenbigl/Marchfeld near Vienna (Austria). Aggregates of six different size classes were obtained by dry-sieving (0-0.25, 0.25-0.5, 0.5-1.0, 1-2, 2-5, 5-10 mm), and characterized geochemically. Quantitative-PCR (Q-PCR) was used to investigate the abundance of bacteria, archaea and fungi, and indicator genes for functional guilds like N-fixation, denitrification, metal reduction, sulphate reduction, and methanogenesis. The Q-PCR results showed that different land-use had significantly different abundances for all the genes, with the cropland site showing the lowest abundance for most of the genes. In contrast, fewer differences were found in gene abundance between the different sizes of soil aggregates, with no specific trends across all the genes, but significant differences related to individual genes and land-use.

van der Zaan, Bas; Blaud, Aimeric; Lair, Georg; Menon, Manoj; Zhang, Dayi; Blum, Winfried; Huang, Wei; van Gaans, Pauline; Banwart, Steve

2014-05-01

95

Analysis of spatial variability of the fractal dimension of soil particle size in Ammopiptanthus mongolicus' desert habitat  

NASA Astrophysics Data System (ADS)

Quantitative analyses of soil texture with the help of the fractal dimensions of soil particle sizes show that fractal dimensions exhibit a significant linear negative correlation with the sand content (>0.1 mm) and a significant power-law positive correlation with the content of clay and silt (<0.05 mm) ( P < 0.0001). However, results revealed that the range of spatial heterogeneity was not restricted to the range of the shrub canopies of the dominant Ammopiptanthus mongolicus communities in the desert region. These results did not support the theory of the “fertile island effect” arising from the interception of fine-grained materials including dust by the shrubs in a desert ecosystem. We hypothesize that the high spatial heterogeneity existing beyond the scope of the shrub canopies and the lack of proper soil substrate conditions required for the invasion of other species, lead to the steady dominance of A. mongolicus communities in these arid desert regions.

Jia, X. H.; Li, X. R.; Zhang, J. G.; Zhang, Z. S.

2009-09-01

96

Host size- and habitat-dependent intensity of Heliconema longissimum (Nematoda: Physalopteridae) in the Japanese eel (Anguilla japonica).  

PubMed

Heliconema longissimum (Ortlepp, 1923) is an ecologically poorly known nematode found in the stomach of Japanese eels, Anguilla japonica Temminck and Schlegel. The occurrence of this nematode in Japanese eels was surveyed in 2 contiguous brackish-water areas (Misho Cove and the lower Renjoji River) of Ehime Prefecture, western Japan, during April 2008 to March 2009. The factors associated with the nematode intensity were also assessed by applying generalized additive models (GAM). Heliconema longissimum exhibited nearly 100% prevalence in both areas, but its intensity differed. The heavier infection in the cove eels indicates that H. longissimum is mainly distributed in the cove, which supports the past speculation for this nematode as a brackish-water parasite. The intensity also increased with the body size of eels. This tendency suggests that the eels inhabiting the cove consume, as they grow, a greater quantity of crustaceans that presumably serve as the nematode's intermediate hosts. PMID:21671717

Katahira, Hirotaka; Mizuno, Kouki; Nagasawa, Kazuya

2011-12-01

97

Exploring Habitats!  

NSDL National Science Digital Library

If you could live anywhere in the world, where would you live? Do you think you could survive anywhere in the world or in any habitat? What types of adaptations might help you survive in your dream habitat? Many places seem great to visit, but you won't know if it's the place for you unless you know the characteristics of the habitat. This lesson will encourage your students to research habitats and adaptations that allow plants and animals to survive in their natural environments.

Brewster, Vanessa

2012-06-14

98

The origin of mitotic sex-chromosome association in the brush-tailed possum, Trichosurus vulpecula (marsupalia:phalangeridae).  

PubMed

Nonrandom associations between the sex chromosomes of the brush-tailed possum, Trichosurus vulpecula, were found to be due to association of nucleolar organizer regions (NOR's) on the X and Y chromosomes. NOR association was also observed between an autosome and the X chromosome. These findings, based on silver staining, are in contrast to the report of MURRAY (1977), who observed sex-chromosome association in this animal and indicated that these nonrandom associations may reflect an association between heterochromatic regions during interphase. We observed only two pairs of NOR's per cell in this animal, one autosomal and one on the sex chromosomes, rather than the several such regions observed by MURRAY, who used an N-banding technique. We discuss the problem of nonhomologous chromosome association in mammalian cells as influenced by heterochromatin and NOR's and find little support for nonhomologous chromosome associations at mitotic metaphase due to heterochromatin association. PMID:6186438

Stock, A D; Mengden, G A

1982-01-01

99

Characteristics of insect populations on habitat fragments: A mini review  

Microsoft Academic Search

Modern human-dominated landscapes are typically characterized by intensive land-use and high levels of habitat destruction, often resulting in sharply contrasted habitat mosaics. Fragmentation of remaining habitat is a major threat to biodiversity. In the present paper, we focus on the different features of habitat fragmentation. First we discuss the importance of pure habitat loss, fragment size, fragment isolation and quality,

Teja Tscharntke; Ingolf Steffan-Dewenter; Andreas Kruess; Carsten Thies

2002-01-01

100

Assessment of anti-bovine IL4 and IFN gamma antibodies to label IL4 and IFN gamma in lymphocytes of the koala and brushtail possum.  

PubMed

We assess anti-bovine IL4 and IFN gamma (IFNg) antibodies for their ability to label IL4 and IFNg in koala (Phascolarctos cinereus), common brushtail possum (Trichosurus vulpecula) and mountain brushtail possum (Trichosurus caninus) lymphocytes using flow cytometry and immunohistochemistry to determine their applicability to studies of host response to intracellular pathogens. Anti-IFNg labelled a product of PMA-ionomycin stimulated sheep, koala and possum lymphocytes. High intensity labelling was not reduced by blocking non-specific binding with 10% FCS; and non-permeabilised koala lymphocytes labelled less, demonstrating that the labelled product was intracellular. The anti-IL4 antibody labelled variably more cells than the irrelevant antibody in some stimulated and non-stimulated preparations in all species but intensity of this labelling was similar to that of cells labelled with the irrelevant antibody. In this study, the antibodies did not label frozen or formalin-fixed tissues in a range of immunohistochemical techniques. We expect the anti-IFNg antibody to be effective in evaluating Th1 responses of koalas and possums exposed to various host, pathogen and environmental factors and add to the limited tools available for investigating the pathogenesis of marsupial diseases, especially those caused by intracellular organisms, such as tuberculosis of brushtail possums and chlamydial disease of koalas. PMID:15350745

Higgins, Damien P; Hemsley, Susan; Canfield, Paul J

2004-10-01

101

Comparison of sediment grain size characteristics on nourished and un-nourished estuarine beaches and impacts on horseshoe crab habitat, Delaware Bay, New Jersey  

USGS Publications Warehouse

This study was undertaken to determine whether nourished and un-nourished estuarine beaches have conspicuous differences in sediment size and sorting that could affect their value as habitat for horseshoe crabs. Comparisons are made of beach profiles and sediment samples gathered at 0.15 m and 0.30 m depths on the backshore, at spring tide elevation, neap tide elevation, and the lower foreshore on 5 un-nourished and 3 nourished beaches in Delaware Bay, where tidal range is <2.0 m. The backshore is at least 0.5 m higher on the recently nourished beaches than on a nearby un-nourished beach reworked by storm waves. Nourishing these beaches to elevations higher than natural overwash heights will restrict natural evolution of the upper beach. Sediments at spring tide elevation on un-nourished sites average 0.72 mm in diameter at 0.15 m depth and 0.67 mm at 0.30 m depth.The similarity in size implies a relatively deep active layer in the zone of maximum cut and fill associated with cyclic profile change during low frequency, high magnitude storms. Sedimentary changes at neap tide elevation may be influenced more by depth of activation by waves than by cycles of deposition and erosion. Sediment at 0.15 m depth at spring and neap locations on the foreshore of nourished beaches is finer (0.51 mm) and better sorted (0.82 phi) than at 0.30 m depth (0.91 mm, 1.38 phi), implying that waves have not reworked the deeper sediments. Differences in sediment characteristics at depth may persist on eroding nourished beaches, where unreworked fill is close to the surface. Sediment texture influences horseshoe crab egg viability and development. Lower rates of water movement through the foreshore and greater thickness of the capillary fringe on nourished sites suggests that greater moisture retention will occur where horseshoe crabs bury eggs and may provide more favorable conditions for egg development, but the depth of these conditions will not be great on a recently nourished beach. ?? 2005 Gebru??der Borntraeger.

Jackson, N. L.; Smith, D. R.; Nordstrom, K. F.

2005-01-01

102

Bottle Habitat  

NSDL National Science Digital Library

This activity is about the impact of climate change in aquatic ecosystems. Learners will build two aquatic habitats using soda bottles and other materials and simulate climate change conditions in one of the habitats. After making daily qualitative and quantitative observations over a four-week period, students will be able to describe the effects of climate change on aquatic ecosystems. This activity is part of the "Climate Change, Wildlife and Wildlands: A Toolkit for Formal and Informal Educators."

103

Chemical characterization of milk oligosaccharides of the common brushtail possum (Trichosurus vulpecula).  

PubMed

Structural characterizations of marsupial milk oligosaccharides have been performed in only three species: the tammar wallaby, the red kangaroo and the koala. To clarify the homology and heterogeneity of milk oligosaccharides among marsupials, 21 oligosaccharides of the milk carbohydrate fraction of the common brushtail possum were characterized in this study. Neutral and acidic oligosaccharides were separated from the carbohydrate fraction of mid-lactation milk and characterized by (1)H-nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The structures of the 7 neutral oligosaccharides were Gal(?1-3)Gal(?1-4)Glc (3'-galactosyllactose), Gal(?1-3)Gal(?1-3)Gal(?1-4)Glc (3", 3'-digalactosyllactose), Gal(?1-3)Gal(?1-3)Gal(?1-3)Gal(?1-4)Glc, Gal(?1-3)Gal(?1-3)Gal(?1-3)Gal(?1-3)Gal(?1-4)Glc, Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc (lacto-N-novopentaose I), Gal(?1-3)Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc (galactosyl lacto-N-novopentaose I), Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-3)Gal(?1-4)Glc (galactosyl lacto-N-novopentaose II). The structures of the 14 acidic oligosaccharides detected were Neu5Ac(?2-3)Gal(?1-3)Gal(?1-4)Glc (sialyl 3'-galactosyllactose), Gal(?1-3)(O-3-sulfate)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc (lacto-N-novopentaose I sulfate a) Gal(?1-3)[Gal(?1-4)(O-3-sulfate)GlcNAc(?1-6)]Gal(?1-4)Glc (lacto-N-novopentaose I sulfate b), Neu5Ac(?2-3)Gal(?1-3)Gal(?1-3)Gal(?1-4)Glc, Neu5Ac(?2-3)Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc (sialyl lacto-N-novopentaose a), Gal(?1-3)(-3-O-sulfate)Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc, Gal(?1-3)Gal(?1-3)[Gal(?1-4)(-3-O-sulfate)GlcNAc(?1-6)]Gal(?1-4)Glc, Gal(?1-3)[Neu5Ac(?2-6)Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc (sialyl lacto-N-novopentaose b), Neu5Ac(?2-3)Gal(?1-3)Gal(?1-3)Gal(?1-3)Gal(?1-4)Glc, Gal(?1-3)(-3-O-sulphate)Gal(?1-3)Gal(?1-3)Gal(?1-3)Gal(?1-4)Glc, Neu5Ac(?2-3)Gal(?1-3)Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc, Gal(?1-3)(-3-O-sulphate)Gal(?1-3)Gal(?1-3)[Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc, Gal(?1-3)Gal(?1-3)Gal(?1-3)[Gal(?1-4)(-3-O-sulphate)GlcNAc(?1-6)]Gal(?1-4)Glc and Gal(?1-3)Gal(?1-3)[Neu5Ac(?2-6)Gal(?1-4)GlcNAc(?1-6)]Gal(?1-4)Glc (galactosyl sialyl lacto-N-novopentaose b). No fucosyl oligosaccharides were detected. Galactosyl lacto-N-novopentaose II, lacto-N-novopentaose I sulfate a, lacto-N-novopentaose I sulfate b and galactosyl sialyl lacto-N-novopentaose b are novel oligosaccharides. The results are compared with those of previous studies on marsupial milk oligosaccharides. PMID:24906475

Urashima, Tadasu; Fujita, Saori; Fukuda, Kenji; Nakamura, Tadashi; Saito, Tadao; Cowan, Phil; Messer, Michael

2014-07-01

104

Aquatic Habitats  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on aquatic habitats and how community wastewater-disposal methods can harm these habitats. Students research the harmful effects of wastewater as well as environmental techniques, then invite a guest speaker to class to discuss this subject and answer their questions. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

105

Combining Site Occupancy, Breeding Population Sizes and Reproductive Success to Calculate Time-Averaged Reproductive Output of Different Habitat Types: An Application to Tricolored Blackbirds  

PubMed Central

In metapopulations in which habitat patches vary in quality and occupancy it can be complicated to calculate the net time-averaged contribution to reproduction of particular populations. Surprisingly, few indices have been proposed for this purpose. We combined occupancy, abundance, frequency of occurrence, and reproductive success to determine the net value of different sites through time and applied this method to a bird of conservation concern. The Tricolored Blackbird (Agelaius tricolor) has experienced large population declines, is the most colonial songbird in North America, is largely confined to California, and breeds itinerantly in multiple habitat types. It has had chronically low reproductive success in recent years. Although young produced per nest have previously been compared across habitats, no study has simultaneously considered site occupancy and reproductive success. Combining occupancy, abundance, frequency of occurrence, reproductive success and nest failure rate we found that that large colonies in grain fields fail frequently because of nest destruction due to harvest prior to fledging. Consequently, net time-averaged reproductive output is low compared to colonies in non-native Himalayan blackberry or thistles, and native stinging nettles. Cattail marshes have intermediate reproductive output, but their reproductive output might be improved by active management. Harvest of grain-field colonies necessitates either promoting delay of harvest or creating alternative, more secure nesting habitats. Stinging nettle and marsh colonies offer the main potential sources for restoration or native habitat creation. From 2005–2011 breeding site occupancy declined 3x faster than new breeding colonies were formed, indicating a rapid decline in occupancy. Total abundance showed a similar decline. Causes of variation in the value for reproduction of nesting substrates and factors behind continuing population declines merit urgent investigation. The method we employ should be useful in other metapopulation studies for calculating time-averaged reproductive output for different sites.

Holyoak, Marcel; Meese, Robert J.; Graves, Emily E.

2014-01-01

106

The effects of parasites on a wild population of the Mountain Brushtail Possum (Trichosurus caninus) in south-eastern Australia.  

PubMed

The effects of a reduction of parasite burdens were determined in adult female Mountain Brushtail Possums, Trichosurus caninus, on the birth, mortality and growth rates of pouch-dependent young, as well as the haematological and serum biochemical values of the mothers. The efficacy of the anthelmintic drug ivermectin for reducing parasite burdens in this host was assessed using faecal and necropsy examinations of a small number of animals. Ivermectin began to reduce parasite burdens by 48 h after treatment. In the second stage of the experiment, animals were treated or sham injected (control individuals) with ivermectin and praziquantel at 8-10-week intervals throughout the breeding season to the time of emergence of young from the pouch. Treatment with ivermectin and praziquantel had no significant effect on the proportion of females giving birth, or on the survival of young to emergence. An effect of treatment was recorded for absolute eosinophil counts in adult females, which, in spring; were higher among control animals than those that were treated. PMID:9650054

Viggers, K L; Lindenmayer, D B; Cunningham, R B; Donnelly, C F

1998-05-01

107

Habitat Observations  

NSDL National Science Digital Library

In this outdoor activity, learners discover the wonders of the habitat surrounding them. After reading "The Empty Lot," a picture book by Dale Fife, learners observe and record in writing what happens in the natural environment around them. Spending time outdoors observing nature can help learners better understand and appreciate the world in which we live.

Aquariums, Association O.

2009-01-01

108

Habitat Demonstration Unit (HDU) Vertical Cylinder Habitat  

NASA Technical Reports Server (NTRS)

NASA's Constellation Architecture Team defined an outpost scenario optimized for intensive mobility that uses small, highly mobile pressurized rovers supported by portable habitat modules that can be carried between locations of interest on the lunar surface. A compact vertical cylinder characterizes the habitat concept, where the large diameter maximizes usable flat floor area optimized for a gravity environment and allows for efficient internal layout. The module was sized to fit into payload fairings for the Constellation Ares V launch vehicle, and optimized for surface transport carried by the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) mobility system. Launch and other loads are carried through the barrel to a top and bottom truss that interfaces with a structural support unit (SSU). The SSU contains self-leveling feet and docking interfaces for Tri-ATHLETE grasping and heavy lift. A pressurized module needed to be created that was appropriate for the lunar environment, could be easily relocated to new locations, and could be docked together in multiples for expanding pressurized volume in a lunar outpost. It was determined that horizontally oriented pressure vessels did not optimize floor area, which takes advantage of the gravity vector for full use. Hybrid hard-inflatable habitats added an unproven degree of complexity that may eventually be worked out. Other versions of vertically oriented pressure vessels were either too big, bulky, or did not optimize floor area. The purpose of the HDU vertical habitat module is to provide pressurized units that can be docked together in a modular way for lunar outpost pressurized volume expansion, and allow for other vehicles, rovers, and modules to be attached to the outpost to allow for IVA (intra-vehicular activity) transfer between them. The module is a vertically oriented cylinder with a large radius to allow for maximal floor area and use of volume. The modular, 5- m-diameter HDU vertical habitat module consists of a 2-m-high barrel with 0.6-mhigh end domes forming the 56-cubicmeter pressure vessel, and a 19-squaremeter floor area. The module has up to four docking ports located orthogonally from each other around the perimeter, and up to one docking port each on the top or bottom end domes. In addition, the module has mounting trusses top and bottom for equipment, and to allow docking with the ATHLETE mobility system. Novel or unique features of the HDU vertical habitat module include the nodelike function with multiple pressure hatches for docking with other versions of itself and other modules and vehicles; the capacity to be carried by an ATHLETE mobility system; and the ability to attach inflatable 'attic' domes to the top for additional pressurized volume.

Howe, Alan; Kennedy, Kriss J.; Gill, Tracy R.; Tri, Terry O.; Toups, Larry; Howard, Robert I.; Spexarth, Gary R.; Cavanaugh, Stephen; Langford, William M.; Dorsey, John T.

2014-01-01

109

The immune response and fertility of koalas (Phascolarctos cinereus) immunised with porcine zonae pellucidae or recombinant brushtail possum ZP3 protein.  

PubMed

To evaluate the potential contraceptive effect of immunisation with zona pellucida antigens, 50 free-ranging koalas were immunised with either porcine zonae pellucidae (PZP), recombinant brushtail possum ZP3 (recBP-ZP3) or buffer, in complete Freund's adjuvant. A single booster immunisation in incomplete Freund's adjuvant was administered 3-5 months later. Where possible animals were recaptured, reproductive status was assessed and blood was collected at 1-3-month intervals for the next 33 months. Forty-three koalas were recaptured at least three times allowing reliable assessments of their fertility. Fourteen animals were observed never to have a pouch young. Of the remaining 29 animals the reproductive productivity of PZP treated females was reduced compared with control and recBP-ZP3 treated females, in terms of both total number of young produced, and failure to produce further young in females of proven fertility. One month after the initial immunisation, serum antigen-specific antibody titres were higher in animals immunised with PZP or recBP-ZP3 compared to controls, and reached a plateau by 4 months. Antibody against the relevant immunising antigen was also detected in ovarian follicular fluid, uterine fluid and vaginal secretions. Epitope analysis suggested that immune responses other than antibodies directed against the ZP3 amino acid sequence were responsible for mediating infertility. The results demonstrate that the fertility of female koalas can be compromised by immunisation against zona pellucida antigens. However, unlike in the eastern grey kangaroo and the brushtail possum, immunisation with bacterial recombinant brushtail possum ZP3 did not compromise fertility in the koala. PMID:19709753

Kitchener, Anne L; Kay, David J; Walters, Bryan; Menkhorst, Peter; McCartney, Carmen A; Buist, Janine A; Mate, Karen E; Rodger, John C

2009-10-01

110

Periodic fluid extrusion and models of digesta mixing in the intestine of a herbivore, the common brushtail possum (Trichosurus vulpecula).  

PubMed

The digesta in four gut compartments (proximal and distal halves of small intestine, caecum, and proximal colon) of a wild hindgut fermenting herbivore, the common brushtail possum (Trichosurus vulpecula), were investigated by rheometry and permeametry. Digesta from all compartments were highly viscous and exhibited shear-thinning. Apparent viscosity was positively related to dry matter content, and increased from proximal small intestine to colon. Dynamic rheological measurements showed that in small intestinal digesta the elastic modulus was greater than the viscous modulus and their ratios were characteristic of weak gels, indicating that digesta could sustain compression. The apparent viscosity of distal small intestinal digesta was markedly lower when measured by capillary viscometry than by rotatory viscometry, indicating that plug flow was likely to be facilitated by lubrication from a peripheral layer of less viscous fluid; i.e., there was an augmented plug flow. Permeametry showed that fluid was extruded from all digesta on compression at physiological pressures, that there was significant permeability of proximal and distal small intestinal digesta, but that digesta became progressively compacted during permeation, with a concomitant reduction in permeability as dry matter content increased. It is proposed that conditions within the small intestine differ from those of an ideal plug flow reactor as radial mixing and turbulence cannot occur. Instead, we suggest that segmentation and peristalsis aid radial mixing of the fluid phase by compressing the solid phase, with extrusion of fluid through the digesta plug. This extrusion may be followed by resorption of fluid back into the plug when the elasticity of the solid phase of digesta is Hookean, thus aiding the mixing of secreted enzymes with insoluble substrates within the plug. PMID:15928916

Lentle, Roger G; Hemar, Yacine; Hall, Christopher E; Stafford, Kevin J

2005-07-01

111

Vesicle-associated protein 1: a novel ovarian immunocontraceptive target in the common brushtail possum, Trichosurus vulpecula.  

PubMed

Ovarian-based immunological research is currently restricted to proteins of the zona pellucida. This study examined the immunocontraceptive potential of a novel vesicle-associated protein, VAP1, previously isolated from the vesicle-rich hemisphere of the brushtail possum oocyte. Seven female possums were immunized against recombinant glutathione S-transferase-VAP1 fusion protein. Control animals (n=3) received antigen-free vaccinations. Following immunization, regular blood sampling determined the level and duration of immune response. Animals were monitored daily, pre- and post-immunization, to determine estrous cycling activity and the percentage of reproductive cycles yielding viable young. The reproductive tracts and somatic organs of VAP1-immunized (n=7), control-immunized (n=3) and non-immunized (n=5) animals were collected and examined by histology and transmission electron microscopy. VAP1 immunization caused a strong and sustained immune response. Elevated levels of VAP1 antibody binding were detected in sera following initial injections, and immune titers rose as boosters were administered. Immunization had no adverse effect upon animal behavior or body condition. Immunized females demonstrated no major change in annual estrous cycling activity; however, the percentage of reproductive cycles resulting in pouch young decreased significantly (P<0.05) by 40%. Histological and ultrastructural analyses revealed an abundance of lipid-like degradation bodies within the ooplasm of developing oocytes and the cytoplasm of failing uterine zygotes. Active macrophage invasion of enlarged endometrial glands was observed in the uteri of two females. Reproductive tract changes are discussed in relation to observed fertility decline. The results of this study indicate that VAP1 has exciting potential as an immunocontraceptive target for possum control in New Zealand. PMID:18713812

Nation, A; Cui, S; Selwood, L

2008-11-01

112

Phagocytosis of sperm cytoplasmic droplets by a specialized region in the epididymis of the brushtailed possum, Trichosurus vulpecula.  

PubMed

During sperm maturation in the brushtailed possum, Trichosurus vulpecula, cytoplasmic droplets are shed from maturing spermatozoa in the distal regions of the head of the epididymis. Examination of luminal contents from various regions of the epididymis showed that the proportion of detached droplets in the luminal contents was reduced from about 45% in the proximal corpus epididymidis to less than 10% in the distal corpus and cauda epididymides. In contrast, the proportion of droplet-free spermatozoa increased from about 45% to more than 90% in the luminal contents. Disappearance of detached cytoplasmic droplets from the lumen was found to be associated with a region of specialized principal cells lining Regions 6 and 7 of the epididymis which selectively sequester and phagocytose free droplets from the luminal milieu. The luminal surfaces of these cells are characterized by a complex system of interdigitating processes which appear as waves of microfolds . These processes contrast with the stereocilia which cover the luminal surfaces of principal cells in adjacent, nonphagocytic regions of the duct. Cytoplasmic droplets are phagocytosed with their limiting membrane intact and gradually become condensed as they are transported deeper into the cell. Membrane lamellae are gradually compacted, transformed into concentrically arranged membrane stacks and then condensed into small electron-dense vesicles, which are probably degraded by the epithelial cells. The presence of a specific recognition factor on cytoplasmic droplets is suggested by the observation that phagocytic principal cells are able to selectively remove detached cytoplasmic droplets from the lumen in the presence of sperm-associated droplets and spermatozoa. PMID:6722242

Temple-Smith, P D

1984-04-01

113

Urban Habitats  

NSDL National Science Digital Library

_Urban Habitats_, published by the Center for Urban Restoration Ecology (CURE), is "a peer-reviewed, fully indexed scientific journal written and edited for a wide audience of researchers, restoration ecologists, park and preserve managers, government officials, and naturalists." The premier issue of this e-journal (focused on urban flora worldwide) is available online, and researchers are encouraged to submit articles and multimedia resources for future issues (detailed submission guidelines provided). CURE is a joint project of Rutgers University and the Brooklyn Botanic Garden.

114

Mars habitat  

NASA Technical Reports Server (NTRS)

The College of Engineering & Architecture at Prairie View A&M University has been participating in the NASA/USRA Advanced Design Program since 1986. The interdisciplinary nature of the program allowed the involvement of students and faculty throughout the College of Engineering & Architecture for the last five years. The research goal for the 1990-1991 year is to design a human habitat on Mars that can be used as a permanent base for 20 crew members. The research is being conducted by undergraduate students from the Department of Architecture.

1991-01-01

115

Testing the generality of the ‘leafing intensity premium’ hypothesis in temperate broad-leaved forests: a survey of variation in leaf size within and between habitats  

Microsoft Academic Search

Because leaf size scales negatively and isometrically with leaf number per shoot size (leafing intensity) in woody species,\\u000a and because most tree and shrub species have small leaves, Kleiman and Aarssen (J Ecol 95:376–382, 2007) recently proposed that natural selection favors high leafing intensity resulting in small leaves, i.e., the leafing-intensity-premium\\u000a hypothesis. However, empirical evidence for or against this hypothesis

Shuang XiangNing; Ning Wu; Shucun Sun

2010-01-01

116

Experimental infection of Australian brushtail possums, Trichosurus vulpecula (Phalangeridae: Marsupialia), with Ross River and Barmah Forest viruses by use of a natural mosquito vector system.  

PubMed

Brushtail possums, Trichosurus vulpecula Kerr, were experimentally infected with Ross River (RR) or Barmah Forest (BF) virus by Aedes vigilax (Skuse) mosquitoes. Eight of 10 animals exposed to RR virus developed neutralizing antibody, and 3 possums developed high viremia for < 48 hr after infection, sufficient to infect recipient mosquitoes. Two of 10 animals exposed to BF virus developed neutralizing antibody. Both infected possums maintained detectable neutralizing antibody to BF for at least 45 days after infection (log neutralization index > 2.0 at 45 days). Eight possums did not develop neutralizing antibody to BF despite exposure to infected mosquitoes. These results suggest that T. vulpecula may potentially act as a reservoir species for RR in urban areas. However, T. vulpecula infected with BF do not develop viremia sufficient to infect mosquitoes and are unlikely to be important hosts for BF. PMID:11791974

Boyd, A M; Hall, R A; Gemmell, R T; Kay, B H

2001-12-01

117

Habitat complexity, brain, and behavior.  

PubMed

More complex brains and behaviors have arisen repeatedly throughout both vertebrate and invertebrate evolution. The challenge is to tease apart the forces underlying such change. In this review, I show how habitat complexity influences both brain and behavior in African cichlid fishes, drawing on examples from primates and birds where appropriate. These species groups share a number of similarities. They exhibit a considerable range of brain to body weight within their group. Often highly visual, the species show a diversity of habitat types, social systems, and cognitive abilities. Phylogenies are well established. In closely-related cichlid fishes from the monophyletic Ectodine clade of Lake Tanganyika, habitat complexity is directly correlated with social variables, including species richness, diversity, and abundance. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are also enhanced in cichlids living in more complex environments. I speculate that species-specific neural effects of environmental complexity could be the consequence of the corresponding social changes. However, environmental and social forces affect brains differently. Environmental forces exert a broader effect on brain structures than social ones, suggesting either allometric expansion of the brain structures in concert with brain size and/or co-evolution of these structures. To advance our understanding of the mechanism by which habitat complexity affects brain and behavior will require the use of closely-related species, quantification of complexity, hypothesis testing restricting analysis to a single variable and path analyses to explore the order of importance of such variables. We will also need new experimental paradigms exploring the cognitive and survival value of brain and brain structure changes both in the laboratory and in the wild. PMID:18836258

Shumway, Caroly A

2008-01-01

118

MODELING PHYSICAL HABITAT PARAMETERS  

EPA Science Inventory

Salmonid populations can be affected by alterations in stream physical habitat. Fish productivity is determined by the stream's physical habitat structure ( channel form, substrate distribution, riparian vegetation), water quality, flow regime and inputs from the watershed (sedim...

119

Urban Areas. Habitat Pac.  

ERIC Educational Resources Information Center

The materials in this educational packet are designed for use with students in grades 4 through 7. They consist of an overview, teaching guides and student data sheets for three activities, and a poster. The overview discusses the city as an ecosystem, changing urban habitats, urban wildlife habitats, values of wildlife, habitat management, and…

Fish and Wildlife Service (Dept. of Interior), Washington, DC.

120

UROPYGIAL GLAND SIZE AND AVIAN HABITAT  

Microsoft Academic Search

The physiological role of the uropygial gland is still controversial. Certain authors state that its function could be closely connected to the hydrophobic properties of its secretion, that may be essential for plumage waterproofing. Therefore, it could be hypothesized that the degree of this gland's develop- ment should be greater in aquatic birds than in terrestrial species. In order to

Diego Montalti; Alfredo Salibián

121

Inhibition of cytochrome P450 enzymes in the Australian brushtail possum, Trichosurus vulpecula: comparison with that of the rat, rabbit, sheep and chicken.  

PubMed

A comparative study was conducted of the inhibition of liver microsomal cytochrome P450 phase I biotransformation enzyme activity of the Australian brushtail possum, rat, rabbit, sheep and chicken. The possum has caused considerable agricultural and ecological problems since its introduction to New Zealand. This work investigated species differences in cytochrome P450 inhibition by selected imidazole derivatives that may be exploited for designing a more species-specific method of toxicological control of the New Zealand possum population. The imidazole derivatives used were ketoconazole, clotrimazole, miconazole and cimetidine. The potency of these inhibitors varied, with clotrimazole and miconazole being most potent, followed by ketoconazole. Cimetidine was the least effective inhibitor. The inhibitory effect of imidazole derivatives on cytochrome p450 phase I biotransformation enzymes appeared more effective in the possum than in other species. All inhibitors used produced type II spectra upon interaction with cytochrome P450 preparations. Possum and chicken microsomal preparations showed absorbancy maxima at 428 nm, rabbit and rat and 429 nm, and sheep at 431 nm. PMID:9682405

Olkowski, A; Gooneratne, R; Eason, C

1998-08-01

122

Assessing the Effectiveness of Tuberculosis Management in Brushtail Possums (Trichosurus vulpecula), through Indirect Surveillance of Mycobacterium bovis Infection Using Released Sentinel Pigs.  

PubMed

In New Zealand, wild pigs acquire Mycobacterium bovis infection by scavenging tuberculous carrion, primarily carcasses of the main disease maintenance host, the brushtail possum (Trichosurus vulpecula). We investigated the utility of captive-reared, purpose-released pigs as sentinels for tuberculosis (TB) following lethal possum control and subsequent population recovery. Within 2-3 years of possum control by intensive poisoning, TB prevalence and the incidence rate of M. bovis infection in released sentinel pigs were lower than in an adjacent area where possums had not been poisoned. Unexpectedly, TB did not decline to near zero levels among pigs in the poisoned area, a fact which reflected an unanticipated rapid increase in the apparent abundance of possums. Monitoring infection levels among resident wild pigs confirmed that TB prevalence, while reduced due to possum control, persisted in the poisoned area at >20% among pigs born 2-3 years after poisoning, while remaining >60% among resident wild pigs in the nonpoisoned area. When fitted with radio-tracking devices, purpose-released pigs provided precise spatial TB surveillance information and facilitated effective killing of wild pigs when employed as "Judas" animals to help locate residents. Sentinel pigs offer value for monitoring disease trends in New Zealand, as TB levels in possums decline nationally due to large-scale possum control. PMID:24804148

Nugent, G; Yockney, I J; Whitford, E J; Cross, M L

2014-01-01

123

Assessing the Effectiveness of Tuberculosis Management in Brushtail Possums (Trichosurus vulpecula), through Indirect Surveillance of Mycobacterium bovis Infection Using Released Sentinel Pigs  

PubMed Central

In New Zealand, wild pigs acquire Mycobacterium bovis infection by scavenging tuberculous carrion, primarily carcasses of the main disease maintenance host, the brushtail possum (Trichosurus vulpecula). We investigated the utility of captive-reared, purpose-released pigs as sentinels for tuberculosis (TB) following lethal possum control and subsequent population recovery. Within 2-3 years of possum control by intensive poisoning, TB prevalence and the incidence rate of M. bovis infection in released sentinel pigs were lower than in an adjacent area where possums had not been poisoned. Unexpectedly, TB did not decline to near zero levels among pigs in the poisoned area, a fact which reflected an unanticipated rapid increase in the apparent abundance of possums. Monitoring infection levels among resident wild pigs confirmed that TB prevalence, while reduced due to possum control, persisted in the poisoned area at >20% among pigs born 2-3 years after poisoning, while remaining >60% among resident wild pigs in the nonpoisoned area. When fitted with radio-tracking devices, purpose-released pigs provided precise spatial TB surveillance information and facilitated effective killing of wild pigs when employed as “Judas” animals to help locate residents. Sentinel pigs offer value for monitoring disease trends in New Zealand, as TB levels in possums decline nationally due to large-scale possum control.

Nugent, G.; Yockney, I. J.; Whitford, E. J.; Cross, M. L.

2014-01-01

124

Living Things: Habitats & Ecosystems  

NSDL National Science Digital Library

Text and photographs regarding habitats, populations and communities, biomes, niches and ecosystems in general with numerous links to lessons, activities, and organizations on specific subtopics in ecology.

2009-01-01

125

The Habitat Project  

ERIC Educational Resources Information Center

The Habitat Project is a multiday, differentiated, interdisciplinary environmental science lesson that incorporates skill-building and motivational strategies to internalize ecosystem vocabulary. Middle school students research an animal, display its physical characteristics on a poster, build a three-dimensional habitat and present their work…

Hein, Annamae J.

2011-01-01

126

Schoolyard Habitat Project Guide.  

ERIC Educational Resources Information Center

This project aims to provide basic steps for students to restore and create wildlife habitats on school grounds. Four chapters are included in this guide, and each chapter is divided into teacher and student sections. Chapter 1 provides necessary information for starting a habitat project. Chapters 2, 3, and 4 discuss the details for the Forest…

Mason, Rich

127

Rocky Intertidal Habitats  

NSDL National Science Digital Library

This resource describes the rocky intertidal habitats of the Monterey Bay National Marine Sanctuary and their biological diversity, distribution patterns, temporal changes, links to other habitats and assemblages, and management issues. Supporting materials include photos, tables, figures, and in-text definitions.

128

Habitat Suitability Information: Common Shiner.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for the common shiner (Notropis cornutus). The models are scaled to produce indices of habitat suitability between 0 (unsuitable habitat) and 1 (opt...

J. G. Trial C. S. Wade J. G. Stanley P. C. Nelson

1983-01-01

129

Cytochrome P450 enzyme activities in the Australian brushtail possum trichosurus vulpesula: a comparison with the rat, rabbit, sheep and chicken.  

PubMed

A comparative study of cytochrome P450 phase 1 biotransformation enzyme activities of the Australian brushtail possum was conducted. Since its introduction to New Zealand this animal pest has caused considerable agricultural and ecological problems. The objective of this work was to probe for potential biochemical weaknesses that may be exploited for designing a more species-specific method of toxicological control of the possum population in New Zealand. Liver microsomal enzyme content and the kinetics of in vitro biotransformation reactions in the possum were quantified and compared with those of the rabbit, rat, chicken and sheep. Significant (p > 0.05) species variations in the liver cytochrome P450 enzyme content were observed. All mammals, including the possum, had considerably higher cytochrome P450, cytochrome b5 and cytochrome reductase levels than the chicken. The chicken had the highest specific phase 1 biotransformation activity (Vmax) for all except 1 of the 8 xenobiotics tested. Among the mammals studied, P450 (Vmax) values in the possum were similar or higher than in the rabbit, rat or sheep. The Km values varied significantly (p > 0.05) between species. The Km for 7-hydroxylation of coumarin was highest in the rat. In comparison with other species, the possum had a lower Km for aromatic hydroxylation of aniline, N-demethylation of N,N-dimethyl aniline, and N-dimethyl aniline, but a higher Km for 0-demethylation of 7-methoxycoumarin, 7-hydroxylation of coumarin, and 0-deethylation of acetophenetidin. It was concluded that phase 1 biotransformation of xenobiotics in the possum is similar to or more efficient than in the other animals tested. PMID:9554057

Olkowski, A; Gooneratne, R; Eason, C

1998-04-01

130

Temporal and spatial dynamics of trypanosomes infecting the brush-tailed bettong (Bettongia penicillata): a cautionary note of disease-induced population decline  

PubMed Central

Background The brush-tailed bettong or woylie (Bettongia penicillata) is on the brink of extinction. Its numbers have declined by 90% since 1999, with their current distribution occupying less than 1% of their former Australian range. Woylies are known to be infected with three different trypanosomes (Trypanosoma vegrandis, Trypanosoma copemani and Trypanosoma sp. H25) and two different strains of T. copemani that vary in virulence. However, the role that these haemoparasites have played during the recent decline of their host is unclear and is part of ongoing investigation. Methods Woylies were sampled from five locations in southern Western Australia, including two neighbouring indigenous populations, two enclosed (fenced) populations and a captive colony. PCR was used to individually identify the three different trypanosomes from blood and tissues of the host, and to investigate the temporal and spatial dynamics of trypanosome infections. Results The spatial pattern of trypanosome infection varied among the five study sites, with a greater proportion of woylies from the Perup indigenous population being infected with T. copemani than from the neighbouring Kingston indigenous population. For an established infection, T. copemani detection was temporally inconsistent. The more virulent strain of T. copemani appeared to regress at a faster rate than the less virulent strain, with the infection possibly transitioning from the acute to chronic phase. Interspecific competition may also exist between T. copemani and T. vegrandis, where an existing T. vegrandis infection may moderate the sequential establishment of the more virulent T. copemani. Conclusion In this study, we provide a possible temporal connection implicating T. copemani as the disease agent linked with the recent decline of the Kingston indigenous woylie population within the Upper Warren region of Western Australia. The chronic association of trypanosomes with the internal organs of its host may be potentially pathogenic and adversely affect their long term fitness and coordination, making the woylie more susceptible to predation.

2014-01-01

131

Quantifying the Direct Transfer Costs of Common Brushtail Possum Dispersal using Least-Cost Modelling: A Combined Cost-Surface and Accumulated-Cost Dispersal Kernel Approach  

PubMed Central

Dispersal costs need to be quantified from empirical data and incorporated into dispersal models to improve our understanding of the dispersal process. We are interested in quantifying how landscape features affect the immediately incurred direct costs associated with the transfer of an organism from one location to another. We propose that least-cost modelling is one method that can be used to quantify direct transfer costs. By representing the landscape as a cost-surface, which describes the costs associated with traversing different landscape features, least-cost modelling is often applied to measure connectivity between locations in accumulated-cost units that are a combination of both the distance travelled and the costs traversed. However, we take an additional step by defining an accumulated-cost dispersal kernel, which describes the probability of dispersal in accumulated-cost units. This novel combination of cost-surface and accumulated-cost dispersal kernel enables the transfer stage of dispersal to incorporate the effects of landscape features by modifying the direction of dispersal based on the cost-surface and the distance of dispersal based on the accumulated-cost dispersal kernel. We apply this approach to the common brushtail possum (Trichosurus vulpecula) within the North Island of New Zealand, demonstrating how commonly collected empirical dispersal data can be used to calibrate a cost-surface and associated accumulated-cost dispersal kernel. Our results indicate that considerable improvements could be made to the modelling of the transfer stage of possum dispersal by using a cost-surface and associated accumulated-cost dispersal kernel instead of a more traditional straight-line distance based dispersal kernel. We envisage a variety of ways in which the information from this novel combination of a cost-surface and accumulated-cost dispersal kernel could be gainfully incorporated into existing dispersal models. This would enable more realistic modelling of the direct transfer costs associated with the dispersal process, without requiring existing dispersal models to be abandoned.

Etherington, Thomas R.; Perry, George L. W.; Cowan, Phil E.; Clout, Mick N.

2014-01-01

132

Anopheline Larval Habitats Seasonality and Species Distribution: A Prerequisite for Effective Targeted Larval Habitats Control Programmes  

PubMed Central

Background Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya. Methods and Findings A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60%) and An.arabiensis (18.34%), the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P?=?0.024) and An. arabiensis (P?=?0.002) larvae. Further, larval species abundance was influenced by crop cycle (P?0.001), grass cover (P?0.001), while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r?=?0.920;P?0.001). The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P?0.001) when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P?=?0.002). When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines. Conclusion These findings suggest that implementation of effective larval control programme should be targeted with larval habitats succession information when larval habitats are fewer and manageable. Crop cycles and distance from habitats to household should be considered as effective information in planning larval control.

Kweka, Eliningaya J.; Zhou, Guofa; Munga, Stephen; Lee, Ming-Chieh; Atieli, Harrysone E.; Nyindo, Mramba; Githeko, Andrew K.; Yan, Guiyun

2012-01-01

133

Lunar Habitat Optimization Using Genetic Algorithms  

NASA Technical Reports Server (NTRS)

Long-duration surface missions to the Moon and Mars will require bases to accommodate habitats for the astronauts. Transporting the materials and equipment required to build the necessary habitats is costly and difficult. The materials chosen for the habitat walls play a direct role in protection against each of the mentioned hazards. Choosing the best materials, their configuration, and the amount required is extremely difficult due to the immense size of the design region. Clearly, an optimization method is warranted for habitat wall design. Standard optimization techniques are not suitable for problems with such large search spaces; therefore, a habitat wall design tool utilizing genetic algorithms (GAs) has been developed. GAs use a "survival of the fittest" philosophy where the most fit individuals are more likely to survive and reproduce. This habitat design optimization tool is a multiobjective formulation of up-mass, heat loss, structural analysis, meteoroid impact protection, and radiation protection. This Technical Publication presents the research and development of this tool as well as a technique for finding the optimal GA search parameters.

SanScoucie, M. P.; Hull, P. V.; Tinker, M. L.; Dozier, G. V.

2007-01-01

134

NORTHWOODS Wildlife Habitat Database  

NSDL National Science Digital Library

Created through a joint effort of the USDA Forest Service's North Central Forest Experiment Station (NCFES) and seven national forests in the Upper Great Lakes Region, NORTHWOODS is a wildlife habitat database featuring "information about the habitat needs of 389 species of reptiles, amphibians, birds, and mammals in the Upper Great Lakes Region." The database compiles common and scientific names, species occurrences in 20 aquatic and terrestrial habitat types, species abundances and seasonal use in seven national forests, and species conservation status. The NORTHWOODS database is available in tab-delimited ASCII file format.

135

Global patterns of fragmentation and connectivity of mammalian carnivore habitat  

PubMed Central

Although mammalian carnivores are vulnerable to habitat fragmentation and require landscape connectivity, their global patterns of fragmentation and connectivity have not been examined. We use recently developed high-resolution habitat suitability models to conduct comparative analyses and to identify global hotspots of fragmentation and connectivity for the world's terrestrial carnivores. Species with less fragmentation (i.e. more interior high-quality habitat) had larger geographical ranges, a greater proportion of habitat within their range, greater habitat connectivity and a lower risk of extinction. Species with higher connectivity (i.e. less habitat isolation) also had a greater proportion of high-quality habitat, but had smaller, not larger, ranges, probably reflecting shorter distances between habitat patches for species with restricted distributions; such species were also more threatened, as would be expected given the negative relationship between range size and extinction risk. Fragmentation and connectivity did not differ among Carnivora families, and body mass was associated with connectivity but not fragmentation. On average, only 54.3 per cent of a species' geographical range comprised high-quality habitat, and more troubling, only 5.2 per cent of the range comprised such habitat within protected areas. Identification of global hotspots of fragmentation and connectivity will help guide strategic priorities for carnivore conservation.

Crooks, Kevin R.; Burdett, Christopher L.; Theobald, David M.; Rondinini, Carlo; Boitani, Luigi

2011-01-01

136

Specialization in habitat use by coral reef damselfishes and their susceptibility to habitat loss  

PubMed Central

While it is generally assumed that specialist species are more vulnerable to disturbance compared with generalist counterparts, this has rarely been tested in coastal marine ecosystems, which are increasingly subject to a wide range of natural and anthropogenic disturbances. Habitat specialists are expected to be more vulnerable to habitat loss because habitat availability exerts a greater limitation on population size, but it is also possible that specialist species may escape effects of disturbance if they use habitats that are generally resilient to disturbance. This study quantified specificity in use of different coral species by six coral-dwelling damselfishes (Chromis viridis, C. atripectoralis, Dascyllus aruanus, D. reticulatus, Pomacentrus moluccensis, and P. amboinensis) and related habitat specialization to proportional declines in their abundance following habitat degradation caused by outbreaks of the coral eating starfish, Acanthaster planci. The coral species preferred by most coral-dwelling damselfishes (e.g., Pocillopora damicornis) were frequently consumed by coral eating crown-of-thorns starfish, such that highly specialized damselfishes were disproportionately affected by coral depletion, despite using a narrower range of different coral species. Vulnerability of damselfishes to this disturbance was strongly correlated with both their reliance on corals and their degree of habitat specialization. Ongoing disturbances to coral reef ecosystems are expected, therefore, to lead to fundamental shifts in the community structure of fish communities where generalists are favored over highly specialist species.

Pratchett, Morgan S; Coker, Darren J; Jones, Geoffrey P; Munday, Philip L

2012-01-01

137

Observing Wetland Habitats  

NSDL National Science Digital Library

Observing Wetland Habitats contains tips on finding wetlands to explore and wetland scavenger hunt observation sheets that can be used as a starting point for discovery. While on their scavenger hunt, students can look for adaptations in plants and animals that help them live in a partially wet habitat. After the students have finished their scavenger hunt, they can share what they've seen and heard.

138

Habitat-Specific Differences in Mercury Concentration in a Top Predator from a Shallow Lake  

Microsoft Academic Search

We conducted a survey of mercury contamination in largemouth bass Micropterus salmoides from Caddo Lake, Texas, and found that fish collected from forested wetland habitat had higher concentrations of mercury than those collected from open-water habitat. Habitat-specific differences in largemouth bass size, age, absolute growth rate, trophic position (based on ?N), and horizontal food web position (based on ?C), characteristics

Matthew M. Chumchal; Ray W. Drenner; Brian Fry; K. David Hambright; Leo W. Newland

2008-01-01

139

Habitat Suitability Index Models: Bobcat  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bobcat (Felis rufus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Boyle, Katherine A.; Fendley, Timothy T.

1987-01-01

140

Habitat Suitability Index Models: Osprey  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the osprey (Pandion haliaetus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Vana-Miller, Sandra L.

1987-01-01

141

Quantifying the direct transfer costs of common brushtail possum dispersal using least-cost modelling: a combined cost-surface and accumulated-cost dispersal kernel approach.  

PubMed

Dispersal costs need to be quantified from empirical data and incorporated into dispersal models to improve our understanding of the dispersal process. We are interested in quantifying how landscape features affect the immediately incurred direct costs associated with the transfer of an organism from one location to another. We propose that least-cost modelling is one method that can be used to quantify direct transfer costs. By representing the landscape as a cost-surface, which describes the costs associated with traversing different landscape features, least-cost modelling is often applied to measure connectivity between locations in accumulated-cost units that are a combination of both the distance travelled and the costs traversed. However, we take an additional step by defining an accumulated-cost dispersal kernel, which describes the probability of dispersal in accumulated-cost units. This novel combination of cost-surface and accumulated-cost dispersal kernel enables the transfer stage of dispersal to incorporate the effects of landscape features by modifying the direction of dispersal based on the cost-surface and the distance of dispersal based on the accumulated-cost dispersal kernel. We apply this approach to the common brushtail possum (Trichosurus vulpecula) within the North Island of New Zealand, demonstrating how commonly collected empirical dispersal data can be used to calibrate a cost-surface and associated accumulated-cost dispersal kernel. Our results indicate that considerable improvements could be made to the modelling of the transfer stage of possum dispersal by using a cost-surface and associated accumulated-cost dispersal kernel instead of a more traditional straight-line distance based dispersal kernel. We envisage a variety of ways in which the information from this novel combination of a cost-surface and accumulated-cost dispersal kernel could be gainfully incorporated into existing dispersal models. This would enable more realistic modelling of the direct transfer costs associated with the dispersal process, without requiring existing dispersal models to be abandoned. PMID:24505467

Etherington, Thomas R; Perry, George L W; Cowan, Phil E; Clout, Mick N

2014-01-01

142

The distribution of groundwater habitats in Europe  

NASA Astrophysics Data System (ADS)

Globalization and planetary environmental changes have stimulated the inventory of groundwater resources and biodiversity at continental and global scales but there has been no concurrent attempt to map the distribution of groundwater habitats even at continental scale. A vector version of the areal information contained in the international hydrogeological map of Europe (IHME) was produced, and thematic indicators for assessing its accuracy were established. Then, groundwater flow type, permeability and pore size were extracted from the vector IHME to define and map the distribution of 13 habitat types. The habitat map was used to test for latitudinal variations in habitat diversity (HD) and whether these variations might in part account for the latitudinal gradient of regional species richness. The HD of river catchments decreased significantly with increasing latitude after correcting for the effect of catchment area. HD decreased by half the amount of deviance attributed to latitude in a regression model of regional species richness, although the explanatory power of HD was probably limited by the coarse resolution of biogeographical regions. The groundwater habitat map of Europe represents a major step for the understanding, assessment and conservation of groundwater biodiversity and for incorporating ecological perspectives in groundwater management policy.

Cornu, Jean-François; Eme, David; Malard, Florian

2013-08-01

143

Determinants of habitat selection by hatchling Australian freshwater crocodiles.  

PubMed

Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk. PMID:22163308

Somaweera, Ruchira; Webb, Jonathan K; Shine, Richard

2011-01-01

144

Comparative habitat use in a juniper woodland bird community  

USGS Publications Warehouse

We compared vegetation structure used by 14 bird species during the 1998 and 1999 breeding seasons to determine what habitat features best accounted for habitat division and community organization in Utah juniper (Juniperus osteosperma) woodlands of southwestern Wyoming. Habitat use was quantified by measuring 24 habitat variables in 461 bird-centered quadrats, each 0.04 ha in size. Using discriminant function analysis, we differentiated between habitat used by 14 bird species along 3 habitat dimensions: (1) variation in shrub cover, overstory juniper cover, mature tree density, understory height, and decadent tree density; (2) a gradient composed of elevation and forb cover; and (3) variation in grass cover, tree height, seedling/sapling cover, and bare ground/rock cover. Of 14 species considered, 9 exhibited substantial habitat partitioning: Mourning Dove (Zenaida macroura), Bewick's Wren (Thryomanes bewickii), Blue-gray Gnatcatcher (Polioptila caerulea), Mountain Bluebird (Sialia currucoides), Plumbeous Vireo (Vireo plumbeus), Green-tailed Towhee (Pipilo chlorurus), Brewer's Sparrow (Spizella breweri), Dark-eyed Junco (Junco hyemalis), and Cassin's Finch (Carpodacus cassinii). Our results indicate juniper bird communities of southwestern Wyoming are organized along a 3-dimensional habitat gradient composed of woodland maturity, elevation, and juniper recruitment. Because juniper birds partition habitat along successional and altitudinal gradients, indiscriminate woodland clearing as well as continued fire suppression will alter species composition. Restoration efforts should ensure that all successional stages of juniper woodland are present on the landscape.

Pavlacky, Jr. , D. C.; Anderson, S. H.

2004-01-01

145

Habitat for Humanity  

NSDL National Science Digital Library

Founded in 1976, Habitat for Humanity has constructed over 175,000 houses, which provides homes for over 1 million people. While the organization's most famous volunteer may be former President Jimmy Carter, the group is always on the lookout for other interested parties who would like to give generously of their time. The organization's website contains information on the history of Habitat, along with information about donating and volunteering for the organization. To get a sense of the scope of their work, visitors will want to take a look at the "Where We Build" section of the site. Utilizing a clickable map, visitors can learn about their different home-building efforts in the countries they serve. To really delve into the work of the organization, visitors would do well to peruse the latest edition of Habitat's "Faces and Places" magazine, which contains articles on rural poverty housing initiatives.

2005-01-01

146

Habitat Suitability Information: Blacknose Dace  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for Blacknose dace, a freshwater species. The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for freshwater, marine, and estuarine areas of the continental United States. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service. Also included are discussions of Suitability Index (SI) curves as used in the Instream Flow Incremental Methodology (IFIM) and SI curves available for an IFIM analysis of Blacknose dace.

Trial, Joan G.; Stanley, Jon G.; Batcheller, Mary; Gebhart, Gary; Maughan, O. Eugene; Nelson, Patrick C.

1983-01-01

147

Habitat Suitability Index Models: Veery  

USGS Publications Warehouse

Habitat preferences and species characteristics of the veery (Catharus fuscesens) are described in this publication. It is one of a series of Habitat Suitability Index (HSI) models and was developed through an analysis of available scientific data on the habitat requirements of the veery. Habitat use information is presented in a review of the literature, followed by the development of an HSI model. The model is presented in three formats: graphic; word; and mathematical. Suitability index graphs quantify the species-habitat relationship. These data are synthesized into a model designed to provide information for use in impact assessment and habitat management.

Sousa, Patrick J.

1982-01-01

148

Habitats of the World  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades K-5. It focuses on habitats of the Earth and how animals and plants adapt to the conditions in which they live. Students divide into groups and research different habitats and how animals and plants have adapted to live in them. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

149

PROCEDURE FOR DETERMINATION OF SEDIMENT PARTICLE SIZE (GRAIN SIZE)  

EPA Science Inventory

Sediment quality and sediment remediation projects have become a high priority for USEPA. Sediment particle size determinations are used in environmental assessments for habitat characterization, chemical normalization, and partitioning potential of chemicals. The accepted met...

150

Comparing quality of estuarine and nearshore intertidal habitats for Carcinus maenas  

NASA Astrophysics Data System (ADS)

Estuarine and nearshore marine areas are vital habitats for several fish and benthic invertebrates. The shore crab Carcinus maenas (Crustacea: Brachyura: Portunidae) inhabits a variety of coastal, estuarine and lagoon habitats. At low tide, habitat structural complexity may be most important for crabs in the intertidal, providing refuge from predation and desiccation. The quality of different vegetated and nonvegetated estuarine and rocky shore habitats in SW Portugal and SW England was evaluated for intertidal C. maenas populations. We estimated population density, size-structure, and potential growth (RNA/DNA ratios) to investigate habitat quality. Vegetated estuarine habitats supported higher crab densities, than nonvegetated estuarine and rocky shore habitats. Investigation of population size-structure revealed that all habitats seem important recruitment and nursery areas although estuarine habitats in SW Portugal appeared to support higher densities of new recruits than equivalent habitats in SW England. Significant variation was found in RNA/DNA ratios among habitats. Ratios were highest in the rocky shore suggesting a high quality habitat where growth potential is high. We speculate that competition from other top-predators ( Pachygrapsus spp.) rather than low habitat quality may limit the occurrence of C. maenas in intertidal rocky shore habitats in SW Portugal. In estuarine environments RNA/DNA ratios were significantly higher in the vegetated than in the nonvegetated estuarine habitats in SW Portugal but not in SW England, suggesting geographic differences in the extent to which highly structure habitats represent high quality. Our results challenge the current paradigm that structured habitats are necessarily those of higher quality for C. maenas.

Amaral, Valter; Cabral, Henrique N.; Jenkins, Stuart; Hawkins, Stephen; Paula, José

2009-06-01

151

Earth is a Marine Habitat. Habitat Conservation Program.  

ERIC Educational Resources Information Center

This brochure is intended to educate the public about the need to conserve and preserve the earth's environment (man's habitat). It contains an introduction to the ocean world and threats to coastal habitat. Photos and narrative revolve around the theme "Earth is a Marine Habitat." Sections include: "The Web of Life,""Oceans and the United…

National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

152

MAINE MARINE WORM HABITAT  

EPA Science Inventory

WORM provides a generalized representation at 1:24,000 scale of commercially harvested marine worm habitat in Maine, based on Maine Department of Marine Resources data from 1970's. Original maps were created by MDMR and published by USF&WS as part of the ""&quo...

153

Habitat Suitability Index Models: Bullfrog.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bullfrog (Rana catesbeiana). The model consolidates habitat use information into a framework appropriate for field application, and is scal...

B. M. Graves S. H Anderson

1987-01-01

154

Habitat Suitability Index Models: Bobcat,  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bobcat (Felis rufus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to p...

K. A. Boyle T. T. Fendley

1987-01-01

155

Habitat Suitability Index Models: Osprey,  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the osprey (Pandion haliaetus). The model consolidates habitat use information into a framework appropriate for field application, and is scale...

S. L. Vana-Miller

1987-01-01

156

Habitat use and preferences of breeding female wood ducks  

USGS Publications Warehouse

Female wood ducks (Aix sponsa) feed primarily on plant foods in the prelaying period and switch to a diet of mostly invertebrates during egg production. If nutrient acquisition is habitat-specific, then selection and use of habitats may differ between these reproductive stages. A better understanding of these processes is needed to assist future habitat conservation and management efforts. In January-May 1999 and 2000, we monitored movements and habitat use of radiomarked females (n = 47) during the prelaying and egg-production periods of first nests. Home-range size averaged 367 ha and did not vary with reproductive period, year, or female age. Habitat use did not differ between periods of prelaying and egg production; consequently, data were combined. Habitat use varied between years, female age, and periods of nest initiation (i.e., early vs. late). Use of beaver ponds (BP), temporary wetlands (TW), managed impoundments (MI), and lake habitats (LK) declined in 2000 compared to 1999, possibly due to reduced precipitation. Nest initiation date was independent of female age. Adult females used BP more than yearlings, and early-nesting females used BP and MI more than late-nesting females. Females selected habitats nonrandomly when habitat composition of the study area was compared to that of home ranges (second-order selection). Lake-influenced wetlands (LI) and MI were ranked highest in preference. Home-range size was inversely related to percentage of the home range comprised of MI and LI, supporting the idea that MI and LI were high-quality habitats. However, we found no relationship between nest initiation date (an important index to reproductive performance) and the combined area of MI and LI in home ranges. Habitai selection did not differ from random when habitat composition of home ranges was compared to that of radio locations (third-order selection). Although MI and LI were preferred, high-quality habitats, our results suggest that breeding female wood ducks can satisfy requirements for egg production using a variety of wetland habitats. We suggest that providing a diversity of habitat types will increase the probability of meeting needs of breeding females throughout the breeding season, especially in areas where wetland conditions frequently change.

Hartke, K. M.; Hepp, G. R.

2004-01-01

157

Linking habitat mosaics and connectivity in a coral reef seascape.  

PubMed

Tropical marine ecosystems are under mounting anthropogenic pressure from overfishing and habitat destruction, leading to declines in their structure and function on a global scale. Although maintaining connectivity among habitats within a seascape is necessary for preserving population resistance and resilience, quantifying movements of individuals within seascapes remains challenging. Traditional methods of identifying and valuing potential coral reef fish nursery habitats are indirect, often relying on visual surveys of abundance and correlations of size and biomass among habitats. We used compound-specific stable isotope analyses to determine movement patterns of commercially important fish populations within a coral reef seascape. This approach allowed us to quantify the relative contributions of individuals from inshore nurseries to reef populations and identify migration corridors among important habitats. Our results provided direct measurements of remarkable migrations by juvenile snapper of over 30 km, between nurseries and reefs. We also found significant plasticity in juvenile nursery residency. Although a majority of individuals on coastal reefs had used seagrass nurseries as juveniles, many adults on oceanic reefs had settled directly into reef habitats. Moreover, seascape configuration played a critical but heretofore unrecognized role in determining connectivity among habitats. Finally, our approach provides key quantitative data necessary to estimate the value of distinctive habitats to ecosystem services provided by seascapes. PMID:22949665

McMahon, Kelton W; Berumen, Michael L; Thorrold, Simon R

2012-09-18

158

Food Availability and Tiger Shark Predation Risk Influence Bottlenose Dolphin Habitat Use  

Microsoft Academic Search

Although both food availability and predation risk have been hypothesized to affect dolphin habitat use and group size, no study has measured both factors concurrently to determine their relative influences. From 1997 to 1999, we investigated the effect of food availability and tiger shark (Galeocerdo cuvier) predation risk on bottlenose dolphin (Tursiops aduncus) habitat use and group size in Shark

Michael R. Heithaus; Lawrence M. Dill

2002-01-01

159

Concepts for a Shroud or Propellant Tank Derived Deep Space Habitat  

NASA Technical Reports Server (NTRS)

Long duration human spaceflight missions beyond Low Earth Orbit will require much larger spacecraft than capsules such as the Russian Soyuz or American Orion Multi-Purpose Crew Vehicle. A concept spacecraft under development is the Deep Space Habitat, with volumes approaching that of space stations such as Skylab, Mir, and the International Space Station. This paper explores several concepts for Deep Space Habitats constructed from a launch vehicle shroud or propellant tank. It also recommends future research using mockups and prototypes to validate the size and crew station capabilities of such a habitat. Keywords: Exploration, space station, lunar outpost, NEA, habitat, long duration, deep space habitat, shroud, propellant tank.

Howard, Robert L.

2012-01-01

160

Integral habitat transport system  

NASA Technical Reports Server (NTRS)

In the 1993 Fall quarter, the ME 4182 design class was sponsored to study various scenarios that needed to be studied for Martian travel. The class was sponsored by NASA and there were several different design projects. The design that group three chose was an integral transport system for a Martian habitat. An integral transport system means the design had to be one that was attached to the habitat. There were several criteria that the design had to meet. Group three performed an in depth study of the Martian environment and looked at several different design ideas. The concept group three developed involved the use of kinematic linkages and the use of Martian gravity to move the habitat. The various design concepts, the criteria matrices and all other aspects that helped group three develop their design can be found in their 1993 ME 4182 design report. Now it is Winter quarter 1994 and group three is faced with another problem. The problem is building a working prototype of their Fall design. The limitations this quarter were the parts. The group had to make the prototype work with existing manufactured parts or make the parts themselves in a machine shop. The prototype was scaled down roughly about twelve times smaller than the original design. The following report describes the actions taken by group three to build a working model.

Elliott, Bill; Frazer, Scott; Higgs, Joey; Huff, Jason; Milam, Tigree

1994-01-01

161

Geomorphology and stream habitat relationships with smallmouth bass ( Micropterus dolomieu ) abundance at multiple spatial scales in eastern Oklahoma  

Microsoft Academic Search

Fluvial geomorphic processes structure habitats important to stream fishes. We determined relationships between densities of smallmouth bass (Micropterus dolomieu) and ecoregions, watershed and reach morphology, and stream habitat in eastern Oklahoma, USA. Watershed and reach morphology were measured at 128 stream sites, and stream habitat and smallmouth bass abundance were measured in 1800 channel units. Variation in stream size, channel

Daniel C. Dauwalter; Dale K. Splinter; William L. Fisher; Richard A. Marston

2007-01-01

162

Introducing Habitats and Biodiversity  

NSDL National Science Digital Library

In this activity, students identify habitats in Arizona, define and illustrate a food web in a kinesthetic exercise, and explain the importance of biodiversity in a writing assignment. Required materials include a ball of yarn or string. The resource includes two student worksheets, a data sheet, answer keys, and Web links. This is Lesson 1 in the unit on Biodiversity, part of IMAGERS, Interactive Media Adventures for Grade School Education using Remote Sensing. The website provides hands-on activities in the classroom supporting the science content in two interactive media books, The Adventures of Echo the Bat and Amelia the Pigeon.

163

Fungal biodiversity in aquatic habitats  

Microsoft Academic Search

Fungal biodiversity in freshwater, brackish and marine habitats was estimated based on reports in the literature. The taxonomic\\u000a groups treated were those with species commonly found on submerged substrates in aquatic habitats: Ascomycetes (exclusive of yeasts), Basidiomycetes, Chytridiomycetes, and the non-fungal Saprolegniales in the Class Oomycetes. Based on presence\\/absence data for a large number and variety of aquatic habitats, about

Carol A. Shearer; Enrique Descals; Brigitte Kohlmeyer; Jan Kohlmeyer; Ludmila Marvanová; David Padgett; David Porter; Huzefa A. Raja; John P. Schmit; Holly A. Thorton; Hermann Voglymayr

2007-01-01

164

Body mass explains characteristic scales of habitat selection in terrestrial mammals.  

PubMed

Niche theory in its various forms is based on those environmental factors that permit species persistence, but less work has focused on defining the extent, or size, of a species' environment: the area that explains a species' presence at a point in space. We proposed that this habitat extent is identifiable from a characteristic scale of habitat selection, the spatial scale at which habitat best explains species' occurrence. We hypothesized that this scale is predicted by body size. We tested this hypothesis on 12 sympatric terrestrial mammal species in the Canadian Rocky Mountains. For each species, habitat models varied across the 20 spatial scales tested. For six species, we found a characteristic scale; this scale was explained by species' body mass in a quadratic relationship. Habitat measured at large scales best-predicted habitat selection in both large and small species, and small scales predict habitat extent in medium-sized species. The relationship between body size and habitat selection scale implies evolutionary adaptation to landscape heterogeneity as the driver of scale-dependent habitat selection. PMID:22393519

Fisher, Jason T; Anholt, Brad; Volpe, John P

2011-12-01

165

Body mass explains characteristic scales of habitat selection in terrestrial mammals  

PubMed Central

Niche theory in its various forms is based on those environmental factors that permit species persistence, but less work has focused on defining the extent, or size, of a species’ environment: the area that explains a species’ presence at a point in space. We proposed that this habitat extent is identifiable from a characteristic scale of habitat selection, the spatial scale at which habitat best explains species’ occurrence. We hypothesized that this scale is predicted by body size. We tested this hypothesis on 12 sympatric terrestrial mammal species in the Canadian Rocky Mountains. For each species, habitat models varied across the 20 spatial scales tested. For six species, we found a characteristic scale; this scale was explained by species’ body mass in a quadratic relationship. Habitat measured at large scales best-predicted habitat selection in both large and small species, and small scales predict habitat extent in medium-sized species. The relationship between body size and habitat selection scale implies evolutionary adaptation to landscape heterogeneity as the driver of scale-dependent habitat selection.

Fisher, Jason T; Anholt, Brad; Volpe, John P

2011-01-01

166

Landscape characteristics of fragmented shrubsteppe habitats and breeding passerine birds  

USGS Publications Warehouse

We examined the influence of local and landscape-level attributes of fragmented habitats in shrubsteppe habitats on the breeding distributions of Sage (Amphispiza belli) and Brewer's (Spizella breweri) Sparrows, Sage Thrashers (Oreoscoptes montanus), Horned Larks (Eremophila alpestris), and Western Meadowlarks (Sturnella neglecta) in the Snake River Plains of southwestern Idaho. We developed habitat (resource) selection models for each species by combining bird counts conducted from 1991 through 1933 with local vegetation characteristics and landscape attributes derived from satellite imagery. Site selection by shrubsteppe species (Sage and Brewer's Sparrows, and Sage Thrashers) depended on local vegetation cover and landscape features, such as the patch size of shrub habitats or the spatial similarity of sites. Marginal sites for these species (with species present in one of three years) were intermediate between unoccupied (never present) and occupied sites along environmental gradients characterized by increasing size of shrub habitat patches and total shrub cover and by decreasing disturbance. Horned Larks and Western Meadowlarks, typical grassland species, were not sensitive to landscape features, and their occupancy depended on the amount of grassland or shrub cover. In contrast to shrubsteppe species, sites that varied by occupancy rates of Western Meadowlarks did not significantly differ in vegetation or landscape components. Our results demonstrate that fragmentation of shrubsteppe significantly influenced the presence of shrub-obligate species. Because of restoration difficulties, the disturbance of semiarid shrubsteppe may cause irreversible loss of habitat and significant long-term consequences for the conservation of shrub-obligate birds.

Knick, Steven T.; Rotenberry, J. T.

1995-01-01

167

Partial gravity habitat study  

NASA Technical Reports Server (NTRS)

The purpose of this study is to investigate comprehensive design requirements associated with designing habitats for humans in a partial gravity environment, then to apply them to a lunar base design. Other potential sites for application include planetary surfaces such as Mars, variable-gravity research facilities, and a rotating spacecraft. Design requirements for partial gravity environments include locomotion changes in less than normal earth gravity; facility design issues, such as interior configuration, module diameter, and geometry; and volumetric requirements based on the previous as well as psychological issues involved in prolonged isolation. For application to a lunar base, it is necessary to study the exterior architecture and configuration to insure optimum circulation patterns while providing dual egress; radiation protection issues are addressed to provide a safe and healthy environment for the crew; and finally, the overall site is studied to locate all associated facilities in context with the habitat. Mission planning is not the purpose of this study; therefore, a Lockheed scenario is used as an outline for the lunar base application, which is then modified to meet the project needs. The goal of this report is to formulate facts on human reactions to partial gravity environments, derive design requirements based on these facts, and apply the requirements to a partial gravity situation which, for this study, was a lunar base.

Capps, Stephen; Lorandos, Jason; Akhidime, Eval; Bunch, Michael; Lund, Denise; Moore, Nathan; Murakawa, Kiosuke

1989-01-01

168

Habitat expansion and contraction in anchovy and sardine populations  

NASA Astrophysics Data System (ADS)

We investigated the relationships between stock biomass, distribution area and mean density of sardine and anchovy populations off California, Peru, South Africa and Japan. Our objective was to elucidate whether their ecological responses to habitat availability and use would support the possibility of them developing synchronic, alternating biomass fluctuations. Results indicate that as populations of both species grow in size, both the area they occupy and their packing density increase, generally consistent with the basin model. The relationship between distribution area and stock biomass is allometric, which implies that there is a limit to the stock expansion to new areas. Patterns of space occupation appear to differ between sardine and anchovy in some regions. In South Africa and Japan anchovy occupies larger area per unit biomass than sardine, consistent with habitat requirements as determined by their feeding ecology. Off California and Peru results confirm that in general species expand their distribution area with stock size, but specific patterns are less clear. Reasons for this are discussed, including sampling biases, the role of upwelling in limiting anchovy’s habitat off Peru, the ability of sardine to use offshore habitats off California, as well as possible differential space occupation patterns during population growth and decline. It is suggested that habitat availability may not be a pre-requisite for sardine growth in some areas, while anchovy may require habitat to become available for populations to grow. The differential habitat dependency and use of space between both species suggests that they cannot be considered to ecologically replace each other. While differences in space utilization may provide opportunities for diverging population paths, the ecological mechanisms behind out-of-phase fluctuations may be much more complex than a simple replacement. The results provide the first comparative, quantitative estimates of biomass/area relationships for pelagic fish, of use in models investigating the potential for expansion and contraction of anchovy and sardine populations worldwide based on climate change-driven habitat predictions.

Barange, Manuel; Coetzee, Janet; Takasuka, Akinori; Hill, Kevin; Gutierrez, Mariano; Oozeki, Yoshioki; Lingen, Carl van der; Agostini, Vera

2009-12-01

169

Modeling Habitat Split: Landscape and Life History Traits Determine Amphibian Extinction Thresholds  

PubMed Central

Habitat split is a major force behind the worldwide decline of amphibian populations, causing community change in richness and species composition. In fragmented landscapes, natural remnants, the terrestrial habitat of the adults, are frequently separated from streams, the aquatic habitat of the larvae. An important question is how this landscape configuration affects population levels and if it can drive species to extinction locally. Here, we put forward the first theoretical model on habitat split which is particularly concerned on how split distance – the distance between the two required habitats – affects population size and persistence in isolated fragments. Our diffusive model shows that habitat split alone is able to generate extinction thresholds. Fragments occurring between the aquatic habitat and a given critical split distance are expected to hold viable populations, while fragments located farther away are expected to be unoccupied. Species with higher reproductive success and higher diffusion rate of post-metamorphic youngs are expected to have farther critical split distances. Furthermore, the model indicates that negative effects of habitat split are poorly compensated by positive effects of fragment size. The habitat split model improves our understanding about spatially structured populations and has relevant implications for landscape design for conservation. It puts on a firm theoretical basis the relation between habitat split and the decline of amphibian populations.

Fonseca, Carlos Roberto; Coutinho, Renato M.; Azevedo, Franciane; Berbert, Juliana M.; Corso, Gilberto; Kraenkel, Roberto A.

2013-01-01

170

A Wildlife Habitat Improvement Plan.  

ERIC Educational Resources Information Center

The document presents an overview of Stony Acres, a "sanctuary" for wildlife as well as a place for recreation enjoyment and education undertakings. A review of the history of wildlife habitat management at Stony Acres and the need for continued and improved wildlife habitat management for the property are discussed in Chapter I. Chapter II…

Rogers, S. Elaine

171

Habitat Suitability Index Models: Juvenile Spot.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop an estuarine habitat model for juvenile spot (Leiostomus xanthurus). The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitabl...

R. R. Stickney M. L. Cuenco

1982-01-01

172

Habitat Suitability Index Models: Pileated Woodpecker.  

National Technical Information Service (NTIS)

A review and synthesis of existing information was used to develop a habitat model for the pileated woodpecker (Dryocopus pileatus). The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitable ha...

R. L. Schroeder

1983-01-01

173

Habitat Suitability Index Models: Common Carp.  

National Technical Information Service (NTIS)

This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the...

E. A. Edwards K. Twomey

1982-01-01

174

Habitat Suitability Index Models: Southern Kingfish.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop marine and estuarine habitat models for Southern Kingfish (Menticirrhus americanus). The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 ...

W. B. Sikora J. P. Sikora

1982-01-01

175

Marine Fisheries Habitat Assessment Improvement Plan.  

National Technical Information Service (NTIS)

NOAAs National Marine Fisheries Service (NMFS) has a mandated responsibility to sustain marine fisheries and associated habitats. The Marine Fisheries Habitat Assessment Improvement Plan (HAIP) defines NMFS unique role in pursuing habitat science and in d...

C. Greene F. Parrish K. Blackhart K. Smith M. Parke M. Yoklavich R. Stone S. K. Brown T. Minello T. Noji W. W. Wakefield

2010-01-01

176

Campus Habitat Improvement Plan  

NSDL National Science Digital Library

In working with students to provide suitable habitat for species of interest, teachers can begin to develop the school campus into an outdoor classroom. Students will build self-esteem while obtaining useful real-life skills related to ecological practices. Students will have the opportunity to work with professionals from related fields of study. The hands-on activities give students a chance to put into practice the theories and themes that have been studied in a closed classroom setting. Students will learn to read aerial photographs, perform biological surveys, and write wildlife management plans. They will carry out management practices on the campus site and learn to evaluate the success of their program.

BEGIN:VCARD VERSION:2.1 FN:Francis Carter N:Carter;Francis ORG:Somerset High School REV:2005-04-15 END:VCARD

1995-06-30

177

Neocortical projections of the suprageniculate and posterior thalamic nuclei in the marsupial brush-tailed possum, Trichosurus vulpecula (Phalangeridae), with a comparative commentary on the organization of the posterior thalamus in marsupial and placental mammals.  

PubMed

Axonal transport methods were used to determine the extent and organisation of neocortical projections from the suprageniculate (SG) and posterior (PO) thalamic nuclei in the brush-tailed possum. Our findings show that SG projects extensively to the auditory cortex, overlapping the cortical projection field of the medial geniculate nucleus, and to the immediately neighbouring association cortex. Though the input relationships of SG appear similar to those reported for other mammals, placental and marsupial, a strong SG projection to auditory cortex has not been reported previously. Neocortical relationships of PO are characterised by an orderly point-to-point projection to all but the most rostral parts of the motor-somaesthetic cortex. There is also a substantial projection to the entire posterior parietal association cortex. The PO-neocortex projection is reciprocally organised. The PO-neocortical projection in the possum is similar to that reported in the Virginia opossum, rat, and several other mammals. There is a major difference in organisation in comparison with certain monkeys where the PO projection is much more restricted and does not involve the motor and somaesthetic cortex. We conclude that PO is similarly organised in many, though not all, mammals, including the marsupials, rodents, insectivores, and prosimian primates. The possum SG, on the other hand, is clearly distinct from other mammals in its extensive projection to auditory cortex, though we cannot say at present whether this a general property of marsupial mammals or a peculiarity restricted to this species and possibly its close relatives. PMID:6886058

Neylon, L; Haight, J R

1983-07-10

178

Types of habitat in the Universe  

NASA Astrophysics Data System (ADS)

From a biological point of view, all environments in the Universe can be categorized into one of three types: uninhabitable, uninhabited habitat or inhabited habitat. This paper describes and defines different habitat types in the Universe with a special focus on environments not usually encountered on the Earth, but which might be common on other planetary bodies. They include uninhabited habitats, subtypes of which are sterile habitats and organic-free habitats. Examples of the different types of environments are provided with reference to the Eyjafjallajökull, Iceland. These habitat types are used to identify testable hypotheses on the abundance of different habitats and the distribution of life in the Universe.

Cockell, Charles S.

2014-04-01

179

QUANTIFYING THE SENSITIVITY OF ARCTIC MARINE MAMMALS TO CLIMATE-INDUCED HABITAT CHANGE  

Microsoft Academic Search

We review seven Arctic and four subarctic marine mammal species, their habitat requirements, and evidence for biological and demographic responses to climate change. We then describe a pan-Arctic quantitative index of species sensitivity to climate change based on population size, geographic range, habitat specificity, diet diversity, migration, site fidelity, sensitivity to changes in sea ice, sensitivity to changes in the

Kristin L. Laidre; Ian Stirling; Lloyd F. Lowry; Øystein Wiig; Mads Peter Heide-Jørgensen; Steven H. Ferguson

2008-01-01

180

ADEQUACY OF VISUALLY CLASSIFIED PARTICLE COUNT STATISTICS FROM REGIONAL STREAM HABITAT SURVEYS  

EPA Science Inventory

Streamlined sampling procedures must be used to achieve a sufficient sample size with limited resources in studies undertaken to evaluate habitat status and potential management-related habitat degradation at a regional scale. At the same time, these sampling procedures must achi...

181

The Effects of Spatial Patterns in Habitat Quality on Community Dynamics within a Site  

Microsoft Academic Search

Metapopulation studies of single species have shown that the size and spatial arrangement of patches of assumed uniformly `suitable' habitat can influence their population dynamics and persistence. We investigated whether variation in the spatial arrangement of `suitable' habitat of varied quality within a single site can affect the abundance and persistence of interacting species. We accomplished this by extending a

R. T. Clarke; J. A. Thomas; G. W. Elmes; M. E. Hochberg

1997-01-01

182

Object?oriented classification of sidescan sonar data for mapping benthic marine habitats  

Microsoft Academic Search

This research presents an object?oriented technique for habitat classification at different segmentation levels based on the use of imagery from an Edgetech 272 side scan sonar. We investigate the success of object parameters such as shape and size as well as texture in discriminating reef from sand habitat. The results are evaluated using traditional digitization, based on visual assessment of

V. L. Lucieer

2008-01-01

183

Habitat Design Considerations for Implementing Solar Particle Event Radiation Protection  

NASA Technical Reports Server (NTRS)

Radiation protection is an important habitat design consideration for human exploration missions beyond Low Earth Orbit. Fortunately, radiation shelter concepts can effectively reduce astronaut exposure for the relatively low proton energies of solar particle events, enabling moderate duration missions of several months before astronaut exposure (galactic cosmic ray and solar particle event) approaches radiation exposure limits. In order to minimize habitat mass for increasingly challenging missions, design of radiation shelters must minimize dedicated, single-purpose shielding mass by leveraging the design and placement of habitat subsystems, accommodations, and consumables. NASA's Advanced Exploration Systems RadWorks Storm Shelter Team has recently designed and performed radiation analysis on several low dedicated mass shelter concepts for a year-long mission. This paper describes habitat design considerations identified during the study's radiation analysis. These considerations include placement of the shelter within a habitat for improved protection, integration of human factors guidance for sizing shelters, identification of potential opportunities for habitat subsystems to compromise on individual subsystem performances for overall vehicle mass reductions, and pre-configuration of shelter components for reduced deployment times.

Simon, Mathew A.; Clowdsley, Martha S.; Walker, Steven A.

2013-01-01

184

Life history strategy influences parasite responses to habitat fragmentation.  

PubMed

Anthropogenic habitat use is a major threat to biodiversity and is known to increase the abundance of generalist host species such as rodents, which are regarded as potential disease carriers. Parasites have an intimate relationship with their host and the surrounding environment and it is expected that habitat fragmentation will affect parasite infestation levels. We investigated the effect of habitat fragmentation on the ecto- and endoparasitic burdens of a broad niche small mammal, Rhabdomys pumilio, in the Western Cape Province, South Africa. Our aim was to look at the effects of fragmentation on different parasite species with diverse life history characteristics and to determine whether general patterns can be found. Sampling took place within pristine lowland (Fynbos/Renosterveld) areas and at fragmented sites surrounded and isolated by agricultural activities. All arthropod ectoparasites and available gastrointestinal endoparasites were identified. We used conditional autoregressive models to investigate the effects of habitat fragmentation on parasite species richness and abundance of all recovered parasites. Host density and body size were larger in the fragments. Combined ecto- as well as combined endoparasite taxa showed higher parasite species richness in fragmented sites. Parasite abundance was generally higher in the case of R. pumilio individuals in fragmented habitats but it appears that parasites that are more permanently associated with the host's body and those that are host-specific show the opposite trend. Parasite life history is an important factor that needs to be considered when predicting the effects of habitat fragmentation on parasite and pathogen transmission. PMID:23954434

Froeschke, Götz; van der Mescht, Luther; McGeoch, Melodie; Matthee, Sonja

2013-12-01

185

Habitat structure alters top-down control in litter communities.  

PubMed

The question whether top-down or bottom-up forces dominate trophic relationships, energy flow, and abundances within food webs has fuelled much ecological research with particular focus on soil litter ecosystems. Because litter simultaneously provides habitat structure and a basal resource, disentangling direct trophic and indirect non-trophic effects on different trophic levels remains challenging. Here, we focussed on short-term per capita interaction strengths of generalist predators (centipedes) on their microbi-detritivore prey (springtails) and addressed how the habitat structuring effects of the leaf litter modifies this interaction. We performed a series of laboratory functional response experiments where four levels of habitat structure were constructed by adding different amounts of leaf litter to the experimental arenas. We found that increased leaf litter reduced the consumption rate of the predator. We interpreted this as a dilution effect of the augmented habitat size provided by the increasing leaf litter surface available to the species. Dilution of the prey population decreased encounter rates, whereas the capture success was not affected. Interestingly, our results imply that top-down control by centipedes decreased with increasing resource supply for the microbi-detritivore prey (i.e. the leaf litter that simultaneously provides habitat structure). Therefore, effective top-down control of predators on microbi-detritvore populations seems unlikely in litter-rich ecosystems due to the non-trophic, habitat-structuring effect of the basal litter resource. PMID:23188055

Kalinkat, Gregor; Brose, Ulrich; Rall, Björn Christian

2013-07-01

186

Habitat selection and productivity of least terns on the lower Platte River, Nebraska  

USGS Publications Warehouse

Least terns (Sterna antillarum) were studied on the lower Platte River, Nebraska, where this endangered population nests on natural sandbar habitat and on sandpit sites created by gravel dredging adjacent to the river. Theoretically terns should select habitats according to habitat suitability. However, the introduction of sandpits and conversion of tallgrass prairies along the river banks to agriculture, residential, and wooded areas may have affected terns' abilities to distinguish suitable habitat or the suitability of nesting habitats in general. I examined habitat selection and productivity of least terns to determine if terns selected habitat according to suitability (as indicated by productivity), what factors affected habitat selection and productivity, and if estimated productivity could support this population. Available habitats of both types were characterized and quantified using aerial videography (1989-90), and habitat use was assessed from census data (1987-90). Productivity of adults and causes and correlates of egg and chick mortality were estimated (1987-90). Population trend was assessed with a deterministic model using my estimates of productivity and a range of survival estimates for Laridae reported in the literature. Terns tended to use river sites with large midstream sandbars and a wide channel, and large sandpit sites with large surface areas of water relative to unused sites on both habitats. Number of sites and area of sand available were estimated using discriminant function analysis of variables quantified from video scenes of both habitats. Terns apparently did not use all potentially available sandbar and sandpit sites because discriminant function factor scores for used and unused sites overlapped broadly for both habitats. Terns did not prefer 1 habitat over the other. Although proportions of available sites used were greater on sandpits than on the river, proportions of available sand used did not differ between habitats. Proportion of terns using each habitat was similar to proportion of available sand on each habitat. The distribution of nest initiation dates and rates of colony-site turnover also were similar on both habitats. Productivity did not differ between habitats but varied significantly among sites. Nest success, fledging success, and fledglings per pair averaged 0.54, 0.28, and 0.47, respectively. Key factor analysis revealed that chick survival had a greater influence on production of Bedglings (on both sandbars and sandpits) than did failure to produce a maximum clutch size or egg mortality. Most egg mortality was caused by predation on sandpits and by flooding on sandbars. Predation was suspected as the major cause of loss for chicks on both habitats. Path analysis revealed no strong or consistent correlations among mortality, numbers of nests and chicks, track trails of intruders into colonies, and habitat variables at colonies on either habitat. Theoretically, terns should not prefer a habitat when habitats are equally suitable if terns have had time to respond to habitat changes. Although sandbars and sandpits appeared equally suitable and terns did not prefer either habitat, local productivity will not support this population unless annual postfledging survival is higher than current estimates for the species. Population trend estimated with fledglings per pair = 0.50 was negative for all but the highest (ca 0.90) rates of annual postfledging survival. Furthermore, deterministic models like the one used in this study overestimate trend. Productivity insufficient to support the local population, in spite of habitat use that reflects habitat suitability, could be due to increased predation caused by habitat alteration adjacent to the river that may have changed the predator community. Alternatively, terns in this area could persist in spite of prevailing low productivity because they are relatively long-lived birds, if highly productive years occasionally occur or if this p

Kirsch, E. M.

1996-01-01

187

Habitat complexity: coral structural loss leads to fisheries declines.  

PubMed

Direct human impacts and global climate change are altering the composition and structure of coral reef habitats. These changes are simplifying size-abundance relationships of reef fish communities, reducing productivity through the system and ultimately threatening fisheries yields. PMID:24801184

Graham, Nicholas A J

2014-05-01

188

Impact of China's May 12 earthquake on Giant Panda habitat in Wenchuan County  

NASA Astrophysics Data System (ADS)

The Minshan and Qionglai mountains, the major distribution range of the Giant Panda (Ailuropoda melanoleuca), was struck by the Wenchuan earthquake. In this study, we evaluated the impact of the earthquake and subsequent geo-disasters on the Giant Panda and its habitat using Wenchuan county (where the epicenter was located) as a case study. Habitat characteristics before and after the earthquake were analyzed based on TM images taken pre and post-earthquake and previous research in this region. Results showed that about 252.0 km2 of panda habitat was lost in Wenchuan County after the earthquake, which accounted for 13.9% of the total habitat in this county. Regions with high earthquake intensity, low elevation, steep slope, and near river had a higher proportion of habitat loss than in other regions. In addition to habitat loss, the earthquake and its resulting geo-disasters also caused habitat fragmentation. After the earthquake, the number of habitat patches increased by a factor of 2 and mean patch size was only 28.3% of pre-earthquake conditions. Habitat restoration and corridor reparation along Road 303 are necessary for facilitating panda's migration between isolated patches. It is necessary to take some measures including relocation of residents and earthquake compensation to decrease the impact of reconstruction on the Giant Panda and its habitat.

Xu, Weihua; Dong, Rencai; Wang, Xuezhi; Ouyang, Zhiyun; Li, Zhiqi; Xiao, Yi; Zhang, Jindong

2009-05-01

189

Habitat classification modeling with incomplete data: Pushing the habitat envelope  

USGS Publications Warehouse

Habitat classification models (HCMs) are invaluable tools for species conservation, land-use planning, reserve design, and metapopulation assessments, particularly at broad spatial scales. However, species occurrence data are often lacking and typically limited to presence points at broad scales. This lack of absence data precludes the use of many statistical techniques for HCMs. One option is to generate pseudo-absence points so that the many available statistical modeling tools can be used. Traditional techniques generate pseudoabsence points at random across broadly defined species ranges, often failing to include biological knowledge concerning the species-habitat relationship. We incorporated biological knowledge of the species-habitat relationship into pseudo-absence points by creating habitat envelopes that constrain the region from which points were randomly selected. We define a habitat envelope as an ecological representation of a species, or species feature's (e.g., nest) observed distribution (i.e., realized niche) based on a single attribute, or the spatial intersection of multiple attributes. We created HCMs for Northern Goshawk (Accipiter gentilis atricapillus) nest habitat during the breeding season across Utah forests with extant nest presence points and ecologically based pseudo-absence points using logistic regression. Predictor variables were derived from 30-m USDA Landfire and 250-m Forest Inventory and Analysis (FIA) map products. These habitat-envelope-based models were then compared to null envelope models which use traditional practices for generating pseudo-absences. Models were assessed for fit and predictive capability using metrics such as kappa, thresholdindependent receiver operating characteristic (ROC) plots, adjusted deviance (Dadj2), and cross-validation, and were also assessed for ecological relevance. For all cases, habitat envelope-based models outperformed null envelope models and were more ecologically relevant, suggesting that incorporating biological knowledge into pseudo-absence point generation is a powerful tool for species habitat assessments. Furthermore, given some a priori knowledge of the species-habitat relationship, ecologically based pseudo-absence points can be applied to any species, ecosystem, data resolution, and spatial extent. ?? 2007 by the Ecological Society of America.

Zarnetske, P. L.; Edwards, Jr. , T. C.; Moisen, G. G.

2007-01-01

190

Pulling the threads together: habitat diversity  

Microsoft Academic Search

The dependence of fungi on host and habitat is emphasized and the reticulate pattern of the interactions explored. Habitat diversity, often defined by the vascular plant element, vertebrate and invertebrate associations, and non-phanerogamic mutualisms are considered. The role of man especially in changes in habitat availability is stressed. Infraspecific variability is mentioned. The diversity of habitats is as much a

Roy Watling

1997-01-01

191

Hedgerows as habitat for woodland plants  

Microsoft Academic Search

For hedgerows to act as corridors for woodland plants they must provide habitat conditions to suit species’ autecological requirements. This supposition was tested by examining differences in the habitat and autecological characteristics of woodland plants according to their relative frequency in hedgerows and woodlands using a novel Habitat Preference Index (HPI). Indicator values for habitat and autecological characteristics of plant

D. McCollin; J. I. Jackson; R. G. H. Bunce; C. J. Barr; R. Stuart

2000-01-01

192

SHORELINE, LAKE, AND ESTUARY SCALE HABITAT RESEARCH  

EPA Science Inventory

Habitat alteration is well recognized as a major cause of loss of living aquatic resources. Many fish and wildlife species depend on several habitats (or on habitat landscapes) in their life histories and migratory patterns. This NHEERL habitat research will develop stressor-re...

193

Habitat-associations of turban snails on intertidal and subtidal rocky reefs.  

PubMed

Patchiness of habitat has important influences on distributions and abundances of organisms. Given the increasing threat of loss and alteration of habitats due to pressures associated with humans, there is a need for ecologists to understand species' requirements for habitat and to predict changes to taxa under various future environmental conditions. This study tested hypotheses about the generality of patterns described for one species of marine intertidal turban snail for a different, yet closely-related species in subtidal habitats along the coast of New South Wales, Australia. These two closely-related species live in similar habitats, yet under quite different conditions, which provided an opportunity to investigate how similar types of habitats influence patterns of distribution, abundance and size-structure in intertidal versus subtidal environments. For each species, there were similar associations between biogenically structured habitat and densities. The intertidal species, Turbo undulates, were more abundant, with greater proportions of small individuals in habitats formed by the canopy-forming alga, Hormosira banksii, the solitary ascidian, Pyura stolonifera or the turfing red alga, Corallina officinalis compared to simple habitat (bare rock). Similarly, more Turbo torquatus were found in biogenically structured subtidal habitat, i.e. canopy-forming algae, Ecklonia radiata, mixed algal communities ('fringe'), or turfing red algae (Corallina officinalis and Amphiroa aniceps) than where habitat is simple (barrens). Small T. torquatus were more abundant in areas of turf and 'fringe', while large snails were more abundant in areas of kelp and barrens. These patterns were found at each location sampled (i.e. eight intertidal and two subtidal rocky reefs) and at all times of sampling, across each environment. This study highlighted the consistent influence of biogenically structured habitats on the distribution, abundance and size-structure of intertidal and subtidal turban snails and forms a basis for increasing the understanding of the potential underlying processes causing such patterns. PMID:23675409

Smoothey, Amy F

2013-01-01

194

Habitat use of American eel (Anguilla rostrata) in a tributary of the Hudson River, New York  

USGS Publications Warehouse

American eel Anguilla rostrata populations are declining over much of their native range. Since American eels spend extended periods in freshwater, understanding their habitat requirements while freshwater residents is important for the management and conservation of this species. As there is little information on American eel habitat use in streams, the ontogenetic, diel, and seasonal habitat use as well as habitat selectivity of three size groups (i.e. ?199 mm total length, 200–399 mm, ?400 mm) of eel were examined in a tributary of the Hudson River. American eels in Hannacroix Creek exhibited ontogenetic, diel, and seasonal variation in habitat use as well as habitat selection. During both summer and autumn all sizes of American eels used larger substrate and more cover during the day. American eels ?199 mm exhibited the strongest habitat selection, whereas eels 200–399 mm exhibited the least. During the autumn all sizes of American eels occupied slower depositional areas where deciduous leaf litter accumulated and provided cover. This may have important implications for in-stream and riparian habitat management of lotic systems used by American eel.

Johnson, James H.; Nack, Christopher C.

2013-01-01

195

Habitat Suitability Index Models: Eastern Brown Pelican  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a habitat model for the eastern brown pelican (Pelecanus occidentalis carolinensis). The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1.0 (optimal habitat) for coastal areas within the eastern brown pelican's breeding range. Habitat suitability indices are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for application of the eastern brown pelican habitat model and techniques for measuring model variables are described.

Hingtgen, Terrence M.; Mulholland, Rosemarie; Zale, Alexander V.

1985-01-01

196

Risk of local extinction of Odonata freshwater habitat generalists and specialists.  

PubMed

Understanding the risk of a local extinction in a single population relative to the habitat requirements of a species is important in both theoretical and applied ecology. Local extinction risk depends on several factors, such as habitat requirements, range size of species, and habitat quality. We studied the local extinctions among 31 dragonfly and damselfly species from 1930 to 1975 and from 1995 to 2003 in Central Finland. We tested whether habitat specialists had a higher local extinction rate than generalist species. Approximately 30% of the local dragonfly and damselfly populations were extirpated during the 2 study periods. The size of the geographical range of the species was negatively related to extinction rate of the local populations. In contrast to our prediction, the specialist species had lower local extinction rates than the generalist species, probably because generalist species occurred in both low- and high-quality habitat. Our results are consistent with source-sink theory. PMID:24405332

Suhonen, Jukka; Korkeamäki, Esa; Salmela, Jukka; Kuitunen, Markku

2014-06-01

197

Habitat Suitability Index Models: Northern Pintail  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the northern pintail (Anas acuta). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Suchy, Willie J.; Anderson, Stanley H.

1987-01-01

198

Habitat Suitability Index Models: Ruffed Grouse  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the ruffed grouse (Bonasa umbellus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Cade, Brian S.; Sousa, Patrick J.

1985-01-01

199

Habitat Suitability Index Models: Swamp Rabbit  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the swamp rabbit (Sylvilagus aquaticus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Allen, Arthur W.

1985-01-01

200

Habitat Suitability Index Models: Eastern Meadowlark  

USGS Publications Warehouse

Habitat preferences of the eastern meadowlark (Sturnella magna) are described in this publication, which is one of a series of Habitat Suitability Index (HSI) models. Habitat use information is presented in a synthesis of the literature on the species-habitat requirements of the eastern meadowlark, followed by the development of the HSI model. The model is presented in three formats: graphic, word, and mathematical, and is designed to provide information for use in impact assessment and habitat management activities.

Schroeder, Richard L.; Sousa, Patrick J.

1982-01-01

201

Habitat Suitability Index Models: Greater Sandhill Crane  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the greater sandhill crane (Grus canadensis tabida). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Armbruster, Michael J.

1987-01-01

202

Habitat Suitability Index Models: Common Carp  

USGS Publications Warehouse

This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the Common carp (Cyprinus carpio) are synthesized. These data are subsequently used to develop Habitat Suitability (HIS) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

Edwards, Elizabeth A.; Twomey, Katie

1982-01-01

203

Habitat Suitability Index Models: Hairy Woodpecker  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the hairy woodpecker (Picoides villosus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Sousa, Patrick J.

1987-01-01

204

Habitat Suitability Index Models: Black Bullhead  

USGS Publications Warehouse

This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the Black bullhead (Ictalurus melas) are synthesized. These data are subsequently used to develop Habitat Suitability (HIS) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

Stuber, Robert J.

1982-01-01

205

Habitat Suitability Index Models: Marsh Wren  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the marsh wren (Cistothorus palustris). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Gutzwiller, Kevin J.; Anderson, Stanley H.

1987-01-01

206

Habitat Suitability Index Models: Cactus Wren  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the cactus wren (Campylorhynchus brunneicapillus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Short, Henry L.

1985-01-01

207

Species Interactions Among Larval Mosquitoes: Context Dependence Across Habitat Gradients  

PubMed Central

Biotic interactions involving mosquito larvae are context dependent, with effects of interactions on populations altered by ecological conditions. Relative impacts of competition and predation change across a gradient of habitat size and permanence. Asymmetrical competition is common and ecological context changes competitive advantage, potentially facilitating landscape-level coexistence of competitors. Predator effects on mosquito populations sometimes depend on habitat structure and on emergent effects of multiple predators, particularly interference among predators. Nonlethal effects of predators on mosquito oviposition, foraging, and life history are common, and their consequences for populations and for mosquito-borne disease are poorly understood. Context-dependent beneficial effects of detritus shredders on mosquitoes occur in container habitats, but these interactions appear to involve more than simple resource modification by shredders. Investigations of context-dependent interactions among mosquito larvae will yield greater understanding of mosquito population dynamics and provide useful model systems for testing theories of context dependence in communities.

Juliano, Steven A.

2009-01-01

208

Coefficients of Productivity for Yellowstone's Grizzly Bear Habitat  

USGS Publications Warehouse

This report describes methods for calculating coefficients used to depict habitat productivity for grizzly bears in the Yellowstone ecosystem. Calculations based on these coefficients are used in the Yellowstone Grizzly Bear Cumulative Effects Model to map the distribution of habitat productivity and account for the impacts of human facilities. The coefficients of habitat productivity incorporate detailed information that was collected over a 20-year period (1977-96) on the foraging behavior of Yellowstone's bears and include records of what bears were feeding on, when and where they fed, the extent of that feeding activity, and relative measures of the quantity consumed. The coefficients also incorporate information, collected primarily from 1986 to 1992, on the nutrient content of foods that were consumed, their digestibility, characteristic bite sizes, and the energy required to extract and handle each food. Coefficients were calculated for different time periods and different habitat types, specific to different parts of the Yellowstone ecosystem. Stratifications included four seasons of bear activity (spring, estrus, early hyperphagia, late hyperphagia), years when ungulate carrion and whitebark pine seed crops were abundant versus not, areas adjacent to (<100 m) or far away from forest/nonforest edges, and areas inside or outside of ungulate winter ranges. Densities of bear activity in each region, habitat type, and time period were incorporated into calculations, controlling for the effects of proximity to human facilities. The coefficients described in this report and associated estimates of grizzly bear habitat productivity are unique among many efforts to model the conditions of bear habitat because calculations include information on energetics derived from the observed behavior of radio-marked bears.

Mattson, David John; Barber, Kim; Maw, Ralene; Renkin, Roy

2004-01-01

209

75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...  

Federal Register 2010, 2011, 2012, 2013

...0648-XX00 Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request for Public Comment...behalf of the interagency Estuary Habitat Restoration Council, is providing notice of...

2010-06-21

210

Ontogenetic and diel variation in stream habitat use by brook trout (Salvelinus fontinalis) in a headwater stream  

USGS Publications Warehouse

Although considerable information exists on habitat use by stream salmonids, only a small portion has quantitatively examined diurnal and nocturnal habitat variation. We examined diel variation in habitat use by age-0 and age-1+ brook trout (Salvelinus fontinalis) during summer and autumn in a headwater stream in northern Pennsylvania. Habitat variables measured included cover, depth, substrate, and velocity. The most pronounced diel variation occurred in the use of cover during both seasons. Both age-0 brook trout and age-1+ trout were associated with less cover at night. Age-0 brook trout occupied swifter water during the day than at night during both seasons, but the difference was not significant. Increased cover, depth, and substrate size governed the habitat of age-1+ brook trout. Our findings support the need for a better understanding of diel differences in habitat use of stream salmonids when considering habitat enhancement and protection.

Johnson, J. H.; Ross, R. M.; Dropkin, D. S.; Redell, L. A.

2011-01-01

211

eHabitat - A web service for habitat similarity modeling with uncertainty propagation  

NASA Astrophysics Data System (ADS)

We are developing eHabitat, a Web Processing Service (WPS) that can model current and future habitat similarity for point observations, polygons defining an existing or hypothetical protected area, or sets of polygons defining the estimated ranges for one or more species. A range of Web Clients makes it easy to use the WPS with predefined data for predictions of the current or future climatic niche. The WPS is also able to document propagating uncertainties of the input data to the estimated similarity maps, if such information is available. The presentation will focus on the architecture of the service and the clients, on how uncertainties are handled by the model and on the presentation of uncertain results. The idea behind eHabitat is that one can classify the similarity between a reference geometry (point locations or polygons) and the surroundings based on one or more species distribution models (SDMs) and a set of ecological indicators. The ecological indicators are typically raster bioclimatic data (DEMs, climate data, vegetation maps …) describing important features for the species or habitats of interest. All these data sets have uncertainties, which can usually be described by treating the value of each pixel as a mean with a standard deviation. As the standard deviation will also be pixel based, it can be given as rasters. If standard deviations of the rasters are not available in the input data, this can also be guesstimated by the service to allow end-users to generate uncertainty scenarios. Rasters of standard deviations are used for simulating a set of spatially correlated maps of the input data, which are then used in the SDM. Additionally, the service can do bootstrapping samples from the input data, which is one of the classic methods for assessing uncertainty of SDMs. The two methods can also be combined, a convenient solution considering that simulation is a computationally much slower process than bootstrapping. Uncertainties in the results produced by eHabitat can be visualized in different ways, as maps, as difference maps in the case of different SDMs, or as the uncertainty of summary statistics such as the habitat replaceability index (HRI) defined as the relative size of the area with a similarity to the training data above a certain threshold.

Olav Skøien, Jon; Schulz, Michael; Dubois, Gregoire; Heuvelink, Gerard

2013-04-01

212

Habitat Suitability Index Models: Black Crappie  

USGS Publications Warehouse

Characteristics and habitat requirements of the black crappie (Pomoxis nigromaculatus) are described in a review of Habitat Suitability Index models. This is one in a series of publications to provide information on the habitat requirements of selected fish and wildlife species. Numerous literature sources have been consulted in an effort to consolidate scientific data on species-habitat relationships. These data have subsequently been synthesized into explicit Habitat Suitability Index (HSI) models. The models are based on suitability indices indicating habitat preferences. Indices have been formulated for variables found to affect the life cycle and survival of each species. Habitat Suitability Index (HSI) models are designed to provide information for use in impact assessment and habitat management activities. The HSI technique is a corollary to the U.S. Fish and Wildlife Service's Habitat Evaluation Procedures.

Edwards, Elizabeth A.; Krieger, Douglas A.; Bacteller, Mary; Maughan, O. Eugene

1982-01-01

213

Multiple foundation species shape benthic habitat islands.  

PubMed

Pattern generation by foundation species (FS) is a primary structuring agent in marine and terrestrial communities. Prior research, focused on single-species or guild-dominated habitats, stressed the role of facilitation in maintaining community structure. However, many habitats are developed by multiple FS from different guilds. Competition between these FS may provide an additional agent potentially responsible for spatial and temporal patterns. In the White Sea, epibenthic patches formed by barnacles (Balanus crenatus) and solitary ascidians (mainly Styela spp. and Molgula spp.) on small stones and empty bivalve shells (mainly Serripes groenlandicus) produce microhabitats for different sessile taxa. We hypothesized that: (1) several FS would provide habitats for most of other species in the community; (2) different FS promote different assemblages of sessile organisms; (3) the interplay of facilitation and competition best explains observed patterns of abundance and demography in FS; and (4) these interactions shape the whole community, increasing the diversity compared to less heterogeneous patches constituted by single FS. We examined 459 patches and the results generally supported this hypothesis. The number of FS in a patch positively affected species diversity. Most sessile species (72% of individuals) resided on barnacles, ascidians and red algae, except barnacles that dominated the primary substrate. The size structure of barnacles (live individuals and empty shells) and ascidians were interrelated, suggesting long-term patch dynamics whereby ascidians regularly replace barnacles. Following this replacement, we expect consequent changes to the entire dependent assemblage. Evidence for these changes exists in the spatial pattern: most sessile and motile taxa demonstrated significant associations with either FS. Our results indicate that the small-scale patterns observed in patches formed by multiple FS are primarily generated by facilitation of dependent taxa by FS, and facilitation and competition between different FS. PMID:18193291

Yakovis, Eugeniy L; Artemieva, Anna V; Shunatova, Natalia N; Varfolomeeva, Marina A

2008-04-01

214

Integrating terrestrial laser scanning and repeat field measurements to quantify habitat changes during baseflow recession  

NASA Astrophysics Data System (ADS)

Understanding stream habitat heterogeneity is essential for evaluating stream habitat quality for salmonids, but the variability in pool sizes, groundwater sources, and the associated water quality makes characterization of habitat challenging. Habitat volume and stream connectivity are key drivers of ecosystem processes in spatially-intermittent streams, and strongly influence survival of juvenile salmonids in coastal California. Stream disconnection creates heterogeneous habitats, as disconnected pools are fed by distinct groundwater and hyporheic sources of water containing different concentrations of carbon, oxygen and nutrients. These distinct biogeochemical regimes drive production of benthic macroinvertebrates (salmonids' primary food source) and dissolved oxygen levels, which in turn govern salmonid metabolism. In this study, we use terrestrial laser scans of the streambed, topographic surveys of wetted pools, and repeat field measurements of pool depth to develop a timeseries of finely resolved pool volumes and dry riffle lengths. We overlay repeat water quality measurements onto this surface to visualize how cessation of flow creates heterogeneous habitats influenced by groundwater flux and geomorphic setting. By coupling terrestrial laser scans with traditional surveys, we create high-resolution facies surfaces that can be integrated with timeseries measurements of other biogeochemical data to characterize changes in habitat conditions during baseflow recession. Compared with traditional survey methods, this method yields improved qualitative descriptions of habitat fragmentation via visualizations and spatially and temporally explicit quantification of aquatic and riparian habitat characteristics that drive salmonid over-summer survival.

Woelfle-Erskine, C. A.; Thompson, S. E.

2013-12-01

215

Diurnal stream habitat use of juvenile Atlantic salmon, brown trout and rainbow trout in winter  

USGS Publications Warehouse

The diurnal winter habitat of three species of juvenile salmonids was examined in a tributary of Skaneateles Lake, NY to compare habitat differences among species and to determine if species/age classes were selecting specific habitats. A total of 792 observations were made on the depth, velocity, substrate and cover (amount and type) used by sympatric subyearling Atlantic salmon, subyearling brown trout and subyearling and yearling rainbow trout. Subyearling Atlantic salmon occurred in shallower areas with faster velocities and less cover than the other salmonid groups. Subyearling salmon was also the only group associated with substrate of a size larger than the average size substrate in the study reach during both winters. Subyearling brown trout exhibited a preference for vegetative cover. Compared with available habitat, yearling rainbow trout were the most selective in their habitat use. All salmonid groups were associated with more substrate cover in 2002 under high flow conditions. Differences in the winter habitat use of these salmonid groups have important management implications in terms of both habitat protection and habitat enhancement.

Johnson, J. H.; Douglass, K. A.

2009-01-01

216

Predictions and retrodictions of the hierarchical representation of habitat in heterogeneous environments  

USGS Publications Warehouse

Interaction between habitat and species is central in ecology. Habitat structure may be conceived as being hierarchical, where larger, more diverse, portions or categories contain smaller, more homogeneous portions. When this conceptualization is combined with the observation that species have different abilities to relate to portions of the habitat that differ in their characteristics, a number of known patterns can be derived and new patterns hypothesized. We propose a quantitative form of this habitat–species relationship by considering species abundance to be a function of habitat specialization, habitat fragmentation, amount of habitat, and adult body mass. The model reproduces and explains patterns such as variation in rank–abundance curves, greater variation and extinction probabilities of habitat specialists, discontinuities in traits (abundance, ecological range, pattern of variation, body size) among species sharing a community or area, and triangular distribution of body sizes, among others. The model has affinities to Holling's textural discontinuity hypothesis and metacommunity theory but differs from both by offering a more general perspective. In support of the model, we illustrate its general potential to capture and explain several empirical observations that historically have been treated independently.

Kolasa, Jurek; Allen, Craig R.; Sendzimir, Jan; Stow, Craig A.

2012-01-01

217

Cometary habitats for primitive life.  

PubMed

Comet Halley studies indicate most of the nucleus is covered by an insulating crust, presumed of pyrolysed organic material. The subcrust is warmed and percolated by gases within 2AU, so provides one habitat for primitive replicating organisms. Cracks and crevices within contaminated ice in the craters provides a habitat for photosynthesising organisms. Subsurface lakes on the Europa model, though insulated by some metres of ice, would require a trigger (perhaps meteorite impact and energy source (chemical or metabolic energy) to initiate and maintain a suitable-habitat on short period comets. Constraints on transfer between comets and other planetary bodies implies that radiation-resistant species with lengthy hibernation potential would be expected. PMID:11538150

Wallis, M K; Wickramasinghe, N C; Hoyle, F

1992-01-01

218

Lunar Habitat Airlock/Suitlock  

NASA Technical Reports Server (NTRS)

Airlocks for lunar Extravehicular Activity (EVA) will be significantly different than previous designs. Until now, airlocks operated infrequently and only in the "clean" weightless environment, but lunar airlocks are planned to be used much more often (every other day) in a dusty, gravity environment. Concepts for airlocks were analyzed by the NASA, JSC Habitability Focus Element during recent lunar outpost studies. Three airlock types were identified; an Airlock (AL) or independent pressure vessel with one hatch to the outside and the other to the Habitat. A Suitlock (SL) which shares a pressure bulkhead with the Habitat allowing rear-entry suits to remain on the dusty side while the crew enters/exits the Habitat. The third option is the Suitport (SP) which offers direct access from the habitable volume into an externally mounted suit. The SP concept was not compared, however between the AL and SL, the AL was favored.

Griffin, Brand Norman

2008-01-01

219

Habitat use among size groups of monomorphic whitefish Coregonus lavaretus  

Microsoft Academic Search

The whitefish (Coregonus lavaretus) in Lake Tyrifjorden, southeastern Norway, is monomorphic with regard to gill raker number: (x=32), and exhibits a bimodal length distribution. The small whitefish (27 cm) were mainly distributed in the upper layers of the pelagic zone. Both small and large whitefish fed on zooplankton in the pelagic zone. In the littoral zone the diet of the

Dag O. Hessen; Jostein Skurdal; Leif Asbjørn Vøllestad; Dag Berge

1986-01-01

220

Habitat Suitability Index Models: Juvenile Spot  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop estuarine habitat models for juvenile spot (Leiostomus xanthurus). The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for estuarine areas of the continental United States. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service. Guideline for juvenile spot model applications and techniques for estimating model variables are described.

Stickney, Robert R.; Cuenco, Michael L.

1982-01-01

221

Habitat Suitability Index Models: Laughing Gull  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a habitat model for laughing gull (Larus atricilla). The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1.0 (optimally suitable habitat) for areas along the Gulf of Mexico coast. Habitat suitability indices are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for application of the model and techniques for measuring model variables are described.

Zale, Alexander V.; Mulholland, Rosemarie

1985-01-01

222

Habitat Suitability Index Models: Clapper Rail  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a model suitable for evaluating the quality of coastal habitat of clapper rails (Rallus longirostris). The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitable habitat) for coastal areas of the continental United States. Habitat suitability indices are designed for use with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for clapper rail model applications and techniques for estimating model variables are discussed.

Lewis, James C.; Garrison, Russell L.

1983-01-01

223

Habitat Suitability Index Models Series  

NSDL National Science Digital Library

The US Geological Survey has just announced the availability of a series of HSI models by the US Fish and Wildlife Service. The HSI models are useful in conjunction with other habitat-based evaluation techniques (Habitat Evaluation Procedures and Instream Flow Incremental Methodology) in developing inventories, impact assessments, and fish and wildlife management plans. All models may be borrowed from Government Depository Libraries and/or the Department of the Interior (USFWS); information is provided at the site. HSI models are available for a range of species, from Alewife/Blueback Herrings to Yellow Warblers.

1999-01-01

224

Habitat expansion among polychaetous annelids repopulating a defaunated marine habitat  

Microsoft Academic Search

Repopulation of the polychaete fauna of a defaunated, marine, intertidal habitat was studied for 2 years.Monthly quantitative samples from 4 stations, from just below mean high water to approximately 10 m below mean low water, were analyzed for species composition, density and distributional relationships. Repopulation occurred most rapidly at the highest tide levels, with slower rates of colonization at lower

D. M. Dauer; J. L. Simon

1976-01-01

225

Habitat provisioning for aboveground predators decreases detritivores.  

PubMed

Although provisioning of habitat by ecosystem engineers is one of the most common biological interactions, previous studies have mostly focused on facilitative or bottom-up processes. Here we show that engineering effects can indirectly strengthen top-down effects mediated by predator abundance. We conducted a small-scale manipulative field experiment and broad-scale field observations of the plant, web spider, and detrital insect system in forest understory habitats. In the field experiment, artificially increasing architectural elements enhanced the abundance of spiders by providing physical support for web building. Moreover, aerial insects derived from the detrital food web decreased in response to increased spider abundance. As artificial architecture per se did not affect aerial detritivores, these results indicate that ecosystem engineering indirectly strengthens top-down effects mediated by predators. In field observations conducted in 12 cedar forests, path analyses supported the importance of an indirect pathway originating from understory vegetation complexity to spider abundance and to aerial detritivores. The effect size of spiders on detrital insects was similar in the field experiment and in the observations. These results indicate that the engineering effects of plants cascade to detrital insects through web spiders across different scales. PMID:18051649

Miyashita, Tadashi; Takada, Mayura

2007-11-01

226

Deep Space Habitat Configurations Based On International Space Station Systems  

NASA Technical Reports Server (NTRS)

A Deep Space Habitat (DSH) is the crew habitation module designed for long duration missions. Although humans have lived in space for many years, there has never been a habitat beyond low-Earth-orbit. As part of the Advanced Exploration Systems (AES) Habitation Project, a study was conducted to develop weightless habitat configurations using systems based on International Space Station (ISS) designs. Two mission sizes are described for a 4-crew 60-day mission, and a 4-crew 500-day mission using standard Node, Lab, and Multi-Purpose Logistics Module (MPLM) sized elements, and ISS derived habitation systems. These durations were selected to explore the lower and upper bound for the exploration missions under consideration including a range of excursions within the Earth-Moon vicinity, near earth asteroids, and Mars orbit. Current methods for sizing the mass and volume for habitats are based on mathematical models that assume the construction of a new single volume habitat. In contrast to that approach, this study explored the use of ISS designs based on existing hardware where available and construction of new hardware based on ISS designs where appropriate. Findings included a very robust design that could be reused if the DSH were assembled and based at the ISS and a transportation system were provided for its return after each mission. Mass estimates were found to be higher than mathematical models due primarily to the use of multiple ISS modules instead of one new large module, but the maturity of the designs using flight qualified systems have potential for improved cost, schedule, and risk benefits.

Smitherman, David; Russell, Tiffany; Baysinger, Mike; Capizzo, Pete; Fabisinski, Leo; Griffin, Brand; Hornsby, Linda; Maples,Dauphne; Miernik, Janie

2012-01-01

227

Deep Space Habitat Configurations Based on International Space Station Systems  

NASA Technical Reports Server (NTRS)

A Deep Space Habitat (DSH) is the crew habitation module designed for long duration missions. Although humans have lived in space for many years, there has never been a habitat beyond low-Earth-orbit. As part of the Advanced Exploration Systems (AES) Habitation Project, a study was conducted to develop weightless habitat configurations using systems based on International Space Station (ISS) designs. Two mission sizes are described for a 4-crew 60-day mission, and a 4-crew 500-day mission using standard Node, Lab, and Multi-Purpose Logistics Module (MPLM) sized elements, and ISS derived habitation systems. These durations were selected to explore the lower and upper bound for the exploration missions under consideration including a range of excursions within the Earth-Moon vicinity, near earth asteroids, and Mars orbit. Current methods for sizing the mass and volume for habitats are based on mathematical models that assume the construction of a new single volume habitat. In contrast to that approach, this study explored the use of ISS designs based on existing hardware where available and construction of new hardware based on ISS designs where appropriate. Findings included a very robust design that could be reused if the DSH were assembled and based at the ISS and a transportation system were provided for its return after each mission. Mass estimates were found to be higher than mathematical models due primarily to the use of multiple ISS modules instead of one new large module, but the maturity of the designs using flight qualified systems have potential for improved cost, schedule, and risk benefits.

Smitherman, David; Russell, Tiffany; Baysinger, Mike; Capizzo, Pete; Fabisinski, Leo; Griffin, Brand; Hornsby, Linda; Maples, Dauphne; Miernik, Janie

2012-01-01

228

Habitat selection by breeding red-winged blackbirds  

USGS Publications Warehouse

Habitat preferences of breeding Red-winged Blackbirds in an agricultural area were determined by comparing population density, landscape characteristics, and vegetational descriptions. Observations were made throughout the breeding season. Preferred breeding habitats of Red-wings, in order of preference, were wetlands, hayfields, old fields, and pastures. Males and females occupied old fields and wetlands first, then hayfields, and finally, pastures. Cutting of hayfields caused territorial abandonment by both sexes within 48 h. The apparent movement of displaced females from cut hayfields to uncut hayfields suggests that habitat fidelity of females is strong after the breeding effort has begun. Breeding Red-wings exhibited general preferences for trees, large amounts of habitat edge, erect old vegetation, and sturdy, tall, and dense vegetation. Vegetative forms and species, such as upland grasses, broad- and narrow-leafed monocots in wetlands, and forbs were important to the Red-wing at various times during the breeding season. Landscape and vegetational preferences of breeding adults were easier to observe early in the breeding season (March through May) than later. Vegetational growth and increases in the size of the breeding population probably make these preferences more difficult to detect. Territory size was poorly correlated with landscape and vegetational characteristics in uplands but strongly correlated with broad- and narrow-leafed mono cots and vegetative height in wetlands. Wetland territories were smaller than upland territories. Territories increased in size during the middle and late portions of the breedi g season. Habitat selection by the Red-winged Blackbird can best be studied by evaluating vegetative preferences throughout the breeding season.

Albers, P.H.

1978-01-01

229

Contact patterns as a risk factor for bovine tuberculosis infection in a free-living adult brushtail possum Trichosurus vulpecula population.  

PubMed

The aim of this study was to identify risk factors for bovine tuberculosis (TB) in a free-roaming, capture-mark-recapture monitored possum Trichosurus vulpecula population in a 22-ha study site at Castlepoint, New Zealand from 1 April 1989 to 31 March 1994. A matched case-control design was used to evaluate the influence of sex, habitat and contact opportunities on TB risk. Cases comprised possums identified as TB-positive throughout the study period. Controls were selected from the group of possums that were captured and showed no clinical signs of TB throughout the study period. Measures derived from a social network analysis of possum capture locations such as degree, clustering coefficient (CC) and betweenness were used to represent potential contact opportunities among possums. Network analysis measures recorded for individual possums in the 12-month period before a diagnosis of TB were evaluated in a conditional logistic regression model. We found no evidence of an association between case status and the total number of possums with which there was potential contact (degree) (P=0.5). The odds of cases being exposed to unit increases in the number of TB-positive contacts was 2.50 (95% CI 1.24-5.05; P<0.01) times that of controls. This effect was conditional on the total number of potential contacts made, with a negative interaction with increasing degree. These findings indicate that potential contact with TB-positive possums increases the odds of disease whereas potential contact with large numbers of possums does not. This suggests that multiple contacts with TB-positive possum(s) are necessary for transmission of TB and this is more likely to occur in networks that are smaller. We challenge the hypothesis that contact with large numbers of individuals increases the probability of becoming TB infected and argue that individual contact behaviour is a determinant of the creation of TB foci within free-living possum populations. PMID:21550126

Porphyre, T; McKenzie, J; Stevenson, M A

2011-07-01

230

Indirect effects of species interactions on habitat provisioning.  

PubMed

Species that shelter in a biogenic habitat can influence their refugia and, in turn, play an essential role in shaping local patterns of biodiversity. Here we explore a positive feedback loop between the provisioning rate of habitat-forming branching corals and their associated fishes and show how interactions between two groups of fish--the planktivorous damselfish and predatory hawkfish--altered the feedback. A field experiment confirmed that skeletal growth of branching coral (genus Pocillopora) increased substantially with increasing numbers (biomass) of resident fishes, likely because they greatly increased the interstitial concentrations of nutrients. Because there is a positive relationship between colony size and number (biomass) of associated fishes (primarily damselfishes in the Family Pomacentridae), a structure-function feedback loop exists in which increasing numbers of damselfish enhance coral growth and larger corals host greater abundances (and species richness) of fish. However, interactions between damselfishes and arc-eye hawkfish, Paracirrhites arcatus, a largely solitary resident, can disrupt this positive feedback loop. Field surveys revealed a marked pattern of fish occupancy related to coral size: Pocillopora colonies of sufficient size to host fish (>40 cm circumference) had either groups of damselfish or an arc-eye hawkfish; only larger colonies (>75 cm) were occupied by both the damselfish and hawkfish. Subsequent short- and long-term experiments revealed that on intermediate-sized Pocillopora colonies, arc-eye hawkfish prevented the establishment of damselfish by suppressing their recruitment. The demographic consequences to the host coral were substantial; in a 1-year-long experiment, intermediate-size Pocillopora occupied by hawkfish grew at half the rate of corals that hosted groups of damselfish. These findings indicate that: (1) species which occupy a biogenic habitat can enhance the provisioning rate of their habitat; (2) such positive feedbacks between community structure and ecosystem function can be disrupted by a strong interactor; (3) even substantial consequences on ecosystem processes that arise can be difficult to discern. PMID:21274572

Holbrook, Sally J; Schmitt, Russell J; Brooks, Andrew J

2011-07-01

231

Habitat complexity facilitates coexistence in a tropical ant community.  

PubMed

The role of habitat complexity in the coexistence of ant species is poorly understood. Here, we examine the influence of habitat complexity on coexistence patterns in ant communities of the remote Pacific atoll of Tokelau. The invasive yellow crazy ant, Anoplolepis gracilipes (Smith), exists in high densities on Tokelau, but still coexists with up to seven other epigeic ant species. The size-grain hypothesis (SGH) proposes that as the size of terrestrial walking organisms decreases, the perceived complexity of the environment increases and predicts that: (1) leg length increases allometrically with body size in ants, and (2) coexistence between ant species is facilitated by differential habitat use according to body size. Analysis of morphological variables revealed variation inconsistent with the morphological prediction of the SGH, as leg length increased allometrically with head length only. We also experimentally tested the ability of epigeic ants in the field to discover and dominate food resources in treatments of differing rugosity. A. gracilipes was consistently the first to discover food baits in low rugosity treatments, while smaller ant species were consistently the first to discover food baits in high rugosity treatments. In addition, A. gracilipes dominated food baits in planar treatments, while smaller ant species dominated baits in rugose treatments. We found that the normally predictable outcomes of exploitative competition between A. gracilipes and other ant species were reversed in the high rugosity treatments. Our results support the hypothesis that differential habitat use according to body size provides a mechanism for coexistence with the yellow crazy ant in Tokelau. The SGH may provide a mechanism for coexistence in other ant communities but also in communities of other terrestrial, walking insects that inhabit a complex landscape. PMID:16763839

Sarty, M; Abbott, K L; Lester, P J

2006-09-01

232

Habitat selection by tundra swans on Northern Alaska breeding grounds  

USGS Publications Warehouse

Habitat selection by the Tundra Swan (Cygnus columbianus columbianus) was evaluated on the Colville River Delta prior to oil field development (1982-1989). Tundra Swan territories comprised a lake, used for refuge and foraging, and terrestrial habitats and ponds near the lakea??s perimeter used for foraging and nesting. Tundra swan sightings from early and late summer aerial surveys were used to investigate habitat selection at the territory and within-territory scale. At the territory or lake scale, swan sightings/lake increased with lake size, and increased from discrete to tapped (i.e., connected to a river channel) to drained lakes within size categories. Overall, 49% of the variation in swan sightings/lake was explained by lake size and type, a size-x-type interaction term, and the proportion of lake perimeter comprised of Halophytic Ponds and Halophytic Wet Meadows. At the within-territory or within-lake scale, foraging swans significantly selected Halophytic Ponds, Halophytic Wet Meadows, and Fresh Ponds relative to Uplands; nesting swans significantly selected Halophytic Ponds and significantly avoided Fresh Wet Meadows relative to Uplands. Vegetation sampling indicated that sites used by Tundra Swans on river channels and tapped lakes were significantly more likely to have Sheathed Pondweed (Potamogeton vaginatus) than control sites. The three major components of Tundra Swan diet were Carex sedges, Sheathed Pondweed, and algae, together comprising 85% of identifiable plant fragments in feces.

Earnst, Susan L.; Rothe, T.

2004-01-01

233

Do Habitat Corridors Provide Connectivity?  

Microsoft Academic Search

Skeptics have questioned the empirical evidence that corridors provide landscape connectivity. Some also have suggested dangers of corridors. We reviewed published studies that empirically addressed whether corridors enhance or diminish the population viability of species in habitat patches connected by cor- ridors. A randomized and replicated experimental design has not been used—and we argue is not required— to make inferences

Paul Beier; Reed F. Noss

1998-01-01

234

Campus Ecology: Habitat Restoration Projects  

NSDL National Science Digital Library

This website provides examples from over 40 campus landscaping projects from colleges across the US. Projects involved "green" practices such as reducing pesticide use, planting native vegetation, minimizing lawn space, removing pavement, or wildlife habitat restoration. The site also includes background information and tips for conducting campus environmental research, as well as links to additional resources.

Federation, National W.

235

Prairie Dog and Habitat Activity  

NSDL National Science Digital Library

This activity allows students to make critical observations on free-ranging, feral animals and investigate their characteristics and habitat. This activity can be adapted to other forms of wildlife. Students will observe, record observations, categorize observations, key out plants, use sampling techniques, follow and devise a protocol, hypothesize, design experiments, conduct experiments, analyze data, and draw conclusions.

Tricia Kritzberger (Mitchell High School)

1996-07-01

236

Enchanted Learning: Biomes-Habitats  

NSDL National Science Digital Library

Created by Enchanted Learning, this kid-friendly Biome-Habitats website introduces children to many of the earth's biomes. Although the site provides basic information about many different biomes, the main emphasis is on the animals that live in each habitat. From the homepage, site visitors can link to almost twenty separate biome / habitat sites including Desert, Cave, Savanna, and Coral Reef-just too name a few. Each site presents a brief introduction covering general characteristics, such as plant life and climate, and then provides links to many separate animal pages ranging from grasshoppers to eagles. The animal pages feature nice diagrams (that can be printed out for coloring) and basic information about anatomy, diet and more. The Biome-Habitats homepage also contains a simple chart listing differences between biomes including elements such as amount of water, temperature range, and soil quality. (Note: While the site asks for a $20 / year donation, it is free to use and requires no registration or fee).

237

MAINE ATLANTIC SALMON HABITAT - GENERAL  

EPA Science Inventory

ASDENN00 describes, at 1:24,000 scale, important Atlantic salmon habitat of the Dennys River in Maine. The coverage was developed from field surveys conducted on the Dennys River in Maine by staff of the Atlantic Salmon Authority and U.S. Fish and Wildlife Service. This survey wa...

238

Habitat Selection and Niche Conservatism  

Microsoft Academic Search

Niche conservatism is the phenomenon in which species or other phyloge- netic lineages seem to exhibit much the same ecological niche over their geo - graphical ranges or over evolutionary time scales. Previous studies have sug- gested that optimal habitat selection can constrain niche evolution (and thus may help explain niche conservatism), in effect by preventing populations from experiencing unfavorable

Robert D. Holt; Michael Barfield

2008-01-01

239

Habitat Complexity, Brain, and Behavior  

Microsoft Academic Search

More complex brains and behaviors have arisen repeatedly throughout both vertebrate and invertebrate evolution. The challenge is to tease apart the forces underlying such change. In this review, I show how habitat complexity influences both brain and behavior in African cichlid fishes, drawing on examples from primates and birds where appropriate. These species groups share a number of similarities. They

Caroly A. Shumway

2008-01-01

240

Habitat Suitability Index Models: Northern Pintail,  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the northern pintail (Anas acuta). The model consolidates habitat use information into a framework appropriate for field application, and is sc...

W. J. Suchy S. H. Anderson

1987-01-01

241

Habitat Suitability Index Models: Ruffed Grouse.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the ruffed grouse (Bonasa umbellus). The model consolidates habitat use information into a framework appropriate for field application, and is ...

B. S. Cade P. J. Sousa

1985-01-01

242

PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY  

EPA Science Inventory

PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY The main objective of this study is to develop criteria for eelgrass habitat establishment and persistence within the Peconic Estuary utilizing various environmental analyses. The Program evaluated water and sediment quality data to...

243

FUTURE SCENARIOS OF CHANGE IN WILDLIFE HABITAT  

EPA Science Inventory

Studies in Pennsylvania, Iowa, California, and Oregon show varying losses of terrestrial wildlife habitat in scenarios based on different assumptions about future human land use patterns. Retrospective estimates of losses of habitat since Euro-American settlement in several stud...

244

Habitat Management for Birds of Alabama.  

National Technical Information Service (NTIS)

This report is a synthesis of existing literature and survey data for Alabama birds. The objectives of this report are to summarize available bird population data for major habitat types in Alabama, to indicate how changes in habitat influence population ...

S. H. Anderson C. S. Robbins J. R. Partelow

1981-01-01

245

Habitat Suitability Index Models: Slough Darter.  

National Technical Information Service (NTIS)

A literature review encompassing habitat and species characteristics of the slough darter (Etheostoma gracile) is followed by a discussion of the relationship of habitat variables and life requisites of this species. These data are then incorporated into ...

E. A. Edwards M. Bacteller O. E. Maughan

1982-01-01

246

Habitat Suitability Index Models: Cactus Wren.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the cactus wren (Campylorhynchus brunneicapillus). The model consolidates habitat use information into a framework appropriate for field applic...

H. L. Short

1985-01-01

247

Habitat Suitability Index Models: Marsh Wren.  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the marsh wren (Cistothorus palustris). The model consolidates habitat use information into a framework appropriate for field application, and ...

K. J. Gutzwiller S. H. Anderson

1987-01-01

248

Critical habitat designation: Is it prudent?  

NASA Astrophysics Data System (ADS)

The critical habitat provision of the US Endangered Species Act was believed by many to be a key feature of the Act. It was believed that this provision would benefit federally listed endangered and threatened species. However, only 23% of the listed species in the United States have their critical habitats designated. The current trend is to forego critical habitat designation because the federal government believes that the Endangered Species Act can protect most listed species without resort to the critical habitat provision. Required publication of critical habitat locations in the Federal Register may draw vandals and collectors to rare species. In other cases, existing habitat protection already provides adequate protection for species. In a few instances critical habitat changes over time and is difficult to delineate. Lastly, designating critical habitat is time consuming, delays species listing, and is controversial, detracting from the positive image of the Endangered Species Act.

Sidle, John G.

1987-08-01

249

Habitat Suitability Index Models: Snapping Turtle,  

National Technical Information Service (NTIS)

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the snapping turtle (Chelydra serpentina). The model consolidates habitat use information into a framework appropriate for field application, a...

B. M. Graves S. H. Anderson

1987-01-01

250

Local extinction of dragonfly and damselfly populations in low- and high-quality habitat patches.  

PubMed

Understanding the risk of extinction of a single population is an important problem in both theoretical and applied ecology. Local extinction risk depends on several factors, including population size, demographic or environmental stochasticity, natural catastrophe, or the loss of genetic diversity. The probability of local extinction may also be higher in low-quality sink habitats than in high-quality source habitats. We tested this hypothesis by comparing local extinction rates of 15 species of Odonata (dragonflies and damselflies) between 1930-1975 and 1995-2003 in central Finland. Local extinction rates were higher in low-quality than in high-quality habitats. Nevertheless, for the three most common species there were no differences in extinction rates between low- and high-quality habitats. Our results suggest that a good understanding of habitat quality is crucial for the conservation of species in heterogeneous landscapes. PMID:20412087

Suhonen, Jukka; Hilli-Lukkarinen, Milla; Korkeamäki, Esa; Kuitunen, Markku; Kullas, Johanna; Penttinen, Jouni; Salmela, Jukka

2010-08-01

251

GHOSTS OF HABITATS PAST: CONTRIBUTION OF LANDSCAPE CHANGE TO CURRENT HABITATS USED BY SHRUBLAND BIRDS  

Microsoft Academic Search

Models of habitat associations for species often are developed with an im- plicit assumption that habitats are static, even though recent disturbance may have altered the landscape. We tested our hypothesis that trajectory and magnitude of habitat change influenced observed distribution and abundance of passerine birds breeding in shrubsteppe habitats of southwestern Idaho. Birds in this region live in dynamic

STEVEN T. K NICK; JOHN T. R OTENBERRY

2000-01-01

252

Mountain restoration: Soil and surface wildlife habitat  

Microsoft Academic Search

Much wildlife habitat is being destroyed by extractive resource industries in mountain environments. This article illustrates how mountain wildlife habitat was restored in a devastated area. A strip mine for coal on the east slopes of the Alberta Rockies, occupied during its operations by Rocky Mountain bighorn sheep (Ovis canadensis canadensis, Shaw 1803), was reclaimed as bighorn habitat. By considering

B. N. MacCullum; V. Geist

1992-01-01

253

Habitat Suitability Index Models: Eastern Meadowlark.  

National Technical Information Service (NTIS)

Habitat preferences of the eastern meadowlark (Sturnella magna) are described in this publication, which is one of a series of Habitat Suitability Index (HSI) models. Habitat use information is presented in a synthesis of the literature on the species-hab...

R. L. Schroeder, P. J. Sousa

1982-01-01

254

EFFECTS OF HABITAT FRAGMENTATION ON BIODIVERSITY  

Microsoft Academic Search

? Abstract The literature on effects of habitat fragmentation on biodiversity is huge. It is also very diverse, with different authors measuring fragmentation in dif- ferent ways and, as a consequence, drawing different conclusions regarding both the magnitude and direction of its effects. Habitat fragmentation is usually defined as a landscape-scale process involving both habitat loss and the breaking apart

Lenore Fahrig

2003-01-01

255

Habitats: Making Homes for Animals and Plants.  

ERIC Educational Resources Information Center

This book of activities is designed to supplement a child's outdoor experiences and to encourage children to take a closer look at nature by creating temporary mini-habitats at home or in school. An introduction explains to students the concept of habitat and the responsibilities of keeping a mini-habitat. The remainder of the book contains…

Hickman, Pamela M.

256

Movements of wintering Dunlin Calidris alpina and changing habitat availability in an agricultural wetland landscape  

USGS Publications Warehouse

Few studies have assessed how the dynamics of wetland bird movements relate to changing resource availability, particularly at more than one spatial scale. Within western Oregon's Williamette Valley, we examined winter resident Dunlin Calidris alpina movements in relation to a decrease in availability of preferred shorebird foraging habitat from early to late winter of 1999-2000. By tracking movements of 15 (early winter) and 12 (late winter) radiomarked individuals, we calculated home ranges and characterized presence/absence of a preference for shorebird foraging habitat during each winter period. Between periods, we compared: (1) percentage of shorebird habitat in home ranges to its availability in the landscape (regional preference), (2) percentage of radio locations in shorebird habitat to its availability within home ranges (local preference) and (3) relative use of roost sites. Concurrent with a 75% decrease in available shorebird habitat from early to late winter, average home range sizes increased by a factor of 3.8. At a regional scale, home ranges in early winter included a significantly greater percentage of shorebird foraging habitat than was available in the wider landscape. However, by late winter, the percent of shorebird habitat in home ranges did not match availability in the landscape. At the local scale, for both winter periods Dunlin were located in shorebird foraging habitat more often than expected given availability of habitat within home ranges [Correction added after online pub-lication 23 May 2008: sentence amended]. An increase in the number of roosts used from early to late winter implies possible reliance on additional sites in late winter for foraging opportunities. Results suggest that wet, unvegetated habitat is sought by Dunlin throughout winter, but individuals could not select home ranges in late winter that fully compensated for seasonal loss of habitat. ?? 2008 The Authors.

Taft, O. W.; Sanzenbacher, P. M.; Haig, S. M.

2008-01-01

257

Secondary production of benthic communities at the habitat scale as a tool to assess ecological integrity in mountain streams  

Microsoft Academic Search

Secondary production of the benthic community was estimated in the four functional habitats identified in the pristine Pioverna stream (Northern Italy): riffle, pool, transition and bedrock habitats. The instantaneous growth, removal-summation and size-frequency methods were used to estimate production. Twelve taxa reached appreciable densities and presumably accounted for most of total benthic production. Three of them belong to the Plecoptera,

Andrea Buffagni; Ester Comin

2000-01-01

258

Secondary production of benthic communities at the habitat scale as a tool to assess ecological integrity in mountain streams  

Microsoft Academic Search

Secondary production of the benthic community was estimated in the four functional habitats identified in the pristine Pioverna stream (Northern Italy): riffle, pool, transition and bedrock habitats. The instantaneous growth, removal-summation and size-frequency methods were used to estimate production. Twelve taxa reached appre- ciable densities and presumably accounted for most of total benthic production. Three of them belong to the

Andrea Buffagni; Ester Comin

2000-01-01

259

Habitat suitability modelling for red deer ( Cervus elaphus L.) in South-central Slovenia with classification trees  

Microsoft Academic Search

We study and assess the potential habitats of a population of red deer in South-central Slovenia. Using existing data on the deer population spatial distribution and size, as well as data on the landscape and ecological properties (GIS) of the area inhabited by this population, we develop a habitat suitability model by automated data analysis using machine learning of classification

Marko Debeljak; Sašo Džeroski; Klemen Jerina; Andrej Kobler; Miha Adami?

2001-01-01

260

Living on the edge: Space use of Eurasian red squirrels in marginal high-elevation habitat  

NASA Astrophysics Data System (ADS)

In marginal habitats located at the edge of a species' range, environmental conditions are frequently extreme and individuals may be subject to different selective pressures compared to central populations. These so-called edge or marginal populations tend to have lower densities and reproductive rates than populations located in more suitable habitats, but little is known about local adaptations in spacing behavior. We studied space use and social organization in a population of Eurasian red squirrels ( Sciurus vulgaris) in a high-elevation marginal habitat of dwarf mountain pine ( Pinus mugo) and compared it with spacing patterns in high-quality Scots pine ( Pinus sylvestris) forest at lower-elevation. Home ranges and core areas were larger in the marginal habitat. In both habitats, males used larger home ranges than females, but sex differences in core area size were significant only in the edge population. Patterns of core area overlap were similar in both habitats with intra-sexual territoriality among adult females and higher degrees of inter-sexual overlap, typical for the species throughout its range. However, low densities in the edge population resulted in higher female by males overlap in spring-summer, suggesting males increased home ranges and core areas during mating season to augment access to estrus females. Thus, in the marginal habitat, with low food abundance and low population densities, linked with extreme winter conditions, squirrels, especially males, used large home ranges. Finally, squirrels responded more strongly to variation in food availability (inverse relation between home range size and seed abundance), and even to fluctuations in density (inverse relation between core area size and density of animals of the same sex), in the marginal than in the high-quality habitat, suggesting high behavioral plasticity to respond to the ecological constraints in marginal habitats.

Romeo, Claudia; Wauters, Lucas A.; Preatoni, Damiano; Tosi, Guido; Martinoli, Adriano

2010-11-01

261

Seasonal habitat use of brook trout and juvenile Atlantic Salmon in a Tributary of Lake Ontario  

USGS Publications Warehouse

The seasonal habitat use of Salvelinus fontinalis (Brook Trout) and subyearling Salmo salar (Atlantic Salmon) was examined in Hart Brook, a tributary of Lake Ontario. Fish habitat use and available habitat were examined during summer and autumn. Interspecific differences in habitat use occurred as well as intraspecific seasonal differences. Overyearling Brook Trout were more selective in their habitat preferences than subyearling Brook Trout or juvenile Atlantic Salmon. Depth and the amount of cover were significantly different among the three fish groups. Salmon occupied faster and shallower water than either age group of trout. Atlantic Salmon were also associated with larger-sized substrate materials than either trout age group, and salmon occurred in habitats with less cover than trout. Overyearling Brook Trout occupied deeper water with more cover than subyearling trout. All three salmonid groups occupied areas with more cover in autumn compared to summer. In autumn, subyearling Brook Trout used deeper areas than they had in the summer. In Hart Brook, the habitat of subyearling Atlantic Salmon can be generally characterized as riffles, the habitat of overyearling Brook Trout was deep pools with extensive cover (35%), and that of subyearling trout was any area with moderate flow and at least 20% cover. As efforts proceed to reintroduce Atlantic Salmon in Lake Ontario, further research is needed to ensure the conservation of Brook Trout populations.

Johnson, J. H.

2008-01-01

262

Fish habitat rehabilitation using wood in the world  

Microsoft Academic Search

To provide river managers and researchers with practical knowledge about fish rehabilitation, various studies of fish habitat\\u000a rehabilitation that used wood were reviewed. The review focuses on fish responses, wood installation methods, and geomorphic\\u000a features of the rehabilitation sites. Most studies were conducted in moderately sized (small and medium) streams with relatively\\u000a high bed gradients and aimed to improve the

Shigeya NagayamaFutoshi Nakamura; Futoshi Nakamura

2010-01-01

263

Habitat Suitability Index Models: American Alligator  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a model for evaluating American alligator habitat quality. The model is applicable in marshes along the northern Gulf of Mexico. It is scaled to produce an index between 0 (unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are described.

Newsom, John D.; Joanen, Ted; Howard, Rebecca J.

1987-01-01

264

Ecological determinism increases with organism size.  

PubMed

After much debate, there is an emerging consensus that the composition of many ecological communities is determined both by species traits, as proposed by niche theory, as well as by chance events. A critical question for ecology is, therefore, which attributes of species predict the dominance of deterministic or stochastic processes. We outline two hypotheses by which organism size could determine which processes structure ecological communities, and we test these hypotheses by comparing the community structure in bromeliad phytotelmata of three groups of organisms (bacteria, zooplankton, and macroinvertebrates) that encompass a 10 000-fold gradient in body size, but live in the same habitat. Bacteria had no habitat associations, as would be expected from trait-neutral stochastic processes, but still showed exclusion among species pairs, as would be expected from niche-based processes. Macroinvertebrates had strong habitat and species associations, indicating niche-based processes. Zooplankton, with body size between bacteria and macroinvertebrates, showed intermediate habitat associations. We concluded that a key niche process, habitat filtering, strengthened with organism size, possibly because larger organisms are both less plastic in their fundamental niches and more able to be selective in dispersal. These results suggest that the relative importance of deterministic and stochastic processes may be predictable from organism size. PMID:22919920

Farjalla, Vinicius F; Srivastava, Diane S; Marino, Nicholas A C; Azevedo, Fernanda D; Dib, Viviane; Lopes, Paloma M; Rosado, Alexandre S; Bozelli, Reinaldo L; Esteves, Francisco A

2012-07-01

265

Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2010  

SciTech Connect

This report describes the 2010 research conducted under the U.S. Army Corps of Engineers (USACE) project EST-P-09-1, titled Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, and known as the 'Salmon Benefits' study. The primary goal of the study is to establish scientific methods to quantify habitat restoration benefits to listed salmon and trout in the lower Columbia River and estuary (LCRE) in three required areas: habitat connectivity, early life history diversity, and survival (Figure ES.1). The general study approach was to first evaluate the state of the science regarding the ability to quantify benefits to listed salmon and trout from habitat restoration actions in the LCRE in the 2009 project year, and then, if feasible, in subsequent project years to develop quantitative indices of habitat connectivity, early life history diversity, and survival. Based on the 2009 literature review, the following definitions are used in this study. Habitat connectivity is defined as a landscape descriptor concerning the ability of organisms to move among habitat patches, including the spatial arrangement of habitats (structural connectivity) and how the perception and behavior of salmon affect the potential for movement among habitats (functional connectivity). Life history is defined as the combination of traits exhibited by an organism throughout its life cycle, and for the purposes of this investigation, a life history strategy refers to the body size and temporal patterns of estuarine usage exhibited by migrating juvenile salmon. Survival is defined as the probability of fish remaining alive over a defined amount of space and/or time. The objectives of the 4-year study are as follows: (1) develop and test a quantitative index of juvenile salmon habitat connectivity in the LCRE incorporating structural, functional, and hydrologic components; (2) develop and test a quantitative index of the early life history diversity of juvenile salmon in the LCRE; (3) assess and, if feasible, develop and test a quantitative index of the survival benefits of tidal wetland habitat restoration (hydrologic reconnection) in the LCRE; and (4) synthesize the results of investigations into the indices for habitat connectivity, early life history diversity, and survival benefits.

Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, J. R.; Dawley, Earl M.; Coleman, Andre M.; Ostrand, Kenneth G.; Hanson, Kyle C.; Woodruff, Dana L.; Donley, Erin E.; Ke, Yinghai; Buenau, Kate E.; Bryson, Amanda J.; Townsend, Richard L.

2011-10-01

266

Subsurface microbial habitats on Mars  

NASA Technical Reports Server (NTRS)

We developed scenarios for shallow and deep subsurface cryptic niches for microbial life on Mars. Such habitats could have considerably prolonged the persistence of life on Mars as surface conditions became increasingly inhospitable. The scenarios rely on geothermal hot spots existing below the near or deep subsurface of Mars. Recent advances in the comparatively new field of deep subsurface microbiology have revealed previously unsuspected rich aerobic and anaerobic microbal communities far below the surface of the Earth. Such habitats, protected from the grim surface conditions on Mars, could receive warmth from below and maintain water in its liquid state. In addition, geothermally or volcanically reduced gases percolating from below through a microbiologically active zone could provide the reducing power needed for a closed or semi-closed microbial ecosystem to thrive.

Boston, P. J.; Mckay, C. P.

1991-01-01

267

Integration Process for the Habitat Demonstration Unit  

NASA Technical Reports Server (NTRS)

The Habitat Demonstration Unit (HDU) is an experimental exploration habitat technology and architecture test platform designed for analog demonstration activities. The HDU previously served as a test bed for testing technologies and sub-systems in a terrestrial surface environment. in 2010 in the Pressurized Excursion Module (PEM) configuration. Due to the amount of work involved to make the HDU project successful, the HDU project has required a team to integrate a variety of contributions from NASA centers and outside collaborators The size of the team and number of systems involved With the HDU makes Integration a complicated process. However, because the HDU shell manufacturing is complete, the team has a head start on FY--11 integration activities and can focus on integrating upgrades to existing systems as well as integrating new additions. To complete the development of the FY-11 HDU from conception to rollout for operations in July 2011, a cohesive integration strategy has been developed to integrate the various systems of HDU and the payloads. The highlighted HDU work for FY-11 will focus on performing upgrades to the PEM configuration, adding the X-Hab as a second level, adding a new porch providing the astronauts a larger work area outside the HDU for EVA preparations, and adding a Hygiene module. Together these upgrades result in a prototype configuration of the Deep Space Habitat (DSH), an element under evaluation by NASA's Human Exploration Framework Team (HEFT) Scheduled activates include early fit-checks and the utilization of a Habitat avionics test bed prior to installation into HDU. A coordinated effort to utilize modeling and simulation systems has aided in design and integration concept development. Modeling tools have been effective in hardware systems layout, cable routing, sub-system interface length estimation and human factors analysis. Decision processes on integration and use of all new subsystems will be defined early in the project to maximize the efficiency of both integration and field operations. In addition a series of tailored design reviews are utilized to quickly define the systems and their integration into the DSH configuration. These processes are necessary to ensure activities, such as partially reversing integration of the X-Hab second story of the HDU and deploying and stowing the new work porch for transportation to the JSC Rock Yard and to the Arizona Black Point Lava Flow Site are performed with minimal or no complications. In addition, incremental test operations leading up to an Integrated systems test allows for an orderly systems test program. For FY-11 activities, the HDU DSH will act as a laboratory utilizing a new X-Hab inflatable second floor with crew habitation features. In addition to the day to day operations involving maintenance of the HDU and exploring the surrounding terrain, testing and optimizing the use of the new X-Hab, work porch, Hygiene Module, and other sub-system enhancements will be the focus of the FY-11 test objectives. The HDU team requires a successful integration strategy using a variety of tools and approaches to prepare the DSH for these test objectives. In a challenging environment where the prototyping influences the system design, as well as Vice versa, results of the HDU DSH field tests will influence future designs of habitat systems.

Gill, Tracy; Merbitz, Jerad; Kennedy, Kriss; Tn, Terry; Toups, Larry; Howe, A. Scott; Smitherman, David

2011-01-01

268

Mapping Deep-sea Habitats  

NSDL National Science Digital Library

In this lesson students investigate bathymetric mapping of deep-sea habitats to see how deep-sea areas of the northwestern Hawaiian Islands can be mapped to facilitate their exploration with a manned submersible. Students will create a two-dimensional topographic map from bathymetric survey data, a three-dimensional model of landforms from a two-dimensional topographic map, and will interpret two- and three-dimensional topographic data.

Goodwin, Mel

269

Carnivorous Plants and Their Habitats  

NSDL National Science Digital Library

This image gallery provides photos of carnivorous plants shown in their natural habitats. The photos are arranged by genus and by geographic region. Each image is accompanied by a brief caption including genus, species, and location. There is also a specialized gallery featuring carnivorous plants of Europe, a discussion on how to cultivate these plants in vitro, and a brief bibliography of publications on carnivorous plants by the site's creator, Dr. Joachim Nerz.

Nerz, Joachim

2002-06-18

270

Potential intertidal habitat restoration sites in the Duwamish River estuary  

SciTech Connect

Restoration of wetland habitats in highly urbanized areas is generally constrained by scarcity of opportunity, adverse impacts of surrounding land use, and cost. Although areal wetland losses approach 98% in Seattle's Duwamish River estuary, the system continues to support important salmonid runs, as well as a variety of bird and mammal species. Estuarine-dependent organisms are likely limited by quality and quantity of intertidal habitat in the system. Because the long-range, estuary-wide benefit of site-specific mitigation and restoration projects is limited, it is imperative to develop estuary-wide restoration plans. Towards this end, an inventory and analysis of potential intertidal habitat restoration sites has been completed for the Duwamish River estuary. Twenty-four sites, ranging in size from 0.8 to 25 acres were identified and comparative functional potential assessed. The majority of these sites (18) occur in the upper estuary. Two sites are located in Elliott Bay, and four are located near the historic mouth of the river in the vicinity of Harbor Island. Spatial data have been developed in geographic information system (GIS) format. Other site-specific data relative to habitat restoration has also been assembled.

Tanner, C.D.

1991-12-01

271

Do habitat shifts drive diversification in teleost fishes? An example from the pufferfishes (Tetraodontidae).  

PubMed

Habitat shifts are implicated as the cause of many vertebrate radiations, yet relatively few empirical studies quantify patterns of diversification following colonization of new habitats in fishes. The pufferfishes (family Tetraodon-tidae) occur in several habitats, including coral reefs and freshwater, which are thought to provide ecological opportunity for adaptive radiation, and thus provide a unique system for testing the hypothesis that shifts to new habitats alter diversification rates. To test this hypothesis, we sequenced eight genes for 96 species of pufferfishes and closely related porcupine fishes, and added 19 species from sequences available in GenBank. We time-calibrated the molecular phylogeny using three fossils, and performed several comparative analyses to test whether colonization of novel habitats led to shifts in the rate of speciation and body size evolution, central predictions of clades experiencing ecological adaptive radiation. Colonization of freshwater is associated with lower rates of cladogenesis in pufferfishes, although these lineages also exhibit accelerated rates of body size evolution. Increased rates of cladogenesis are associated with transitions to coral reefs, but reef lineages surprisingly exhibit significantly lower rates of body size evolution. These results suggest that ecological opportunity afforded by novel habitats may be limited for pufferfishes due to competition with other species, constraints relating to pufferfish life history and trophic ecology, and other factors. PMID:23496826

Santini, F; Nguyen, M T T; Sorenson, L; Waltzek, T B; Lynch Alfaro, J W; Eastman, J M; Alfaro, M E

2013-05-01

272

Demersal fish and habitat associations from visual surveys on the central California shelf  

NASA Astrophysics Data System (ADS)

In 2004, we surveyed demersal fishes and habitats on the continental shelf off central California (65-110 m depth) using the occupied submersible Delta. Our objectives were to estimate the relative abundance of habitats and to examine demersal fish species composition, diversity, density, and sizes relative to these habitats. A total of 112 transects were completed covering 32 km of seafloor. A higher density of fishes was estimated in boulder and cobble habitats than in mud and brachiopod beds. More than 80% of the fishes were small, measuring 20 cm or less in total length. Species with small maximum size (primarily pygmy rockfish, Sebastes wilsoni, and blackeye gobies, Rhinogobiops nicholsii) accounted for nearly half (49%) of the total number of 12,441 fishes. Most fishes were immature, with only 4 of 20 harvested species having more than 50% of the individuals larger than the size at first maturity. Our study area on the continental shelf may be an ontogenetic transition zone for immature fishes before they move to their adult habitat on the slope. Alternatively, historical fishing pressure may have contributed to the lack of large, mature fishes in the survey area. Understanding the importance of these habitats to fishes at various life stages will improve our ability to assess these deepwater fish stocks and effectively manage these living resources on an ecosystem basis.

Laidig, Thomas E.; Watters, Diana L.; Yoklavich, Mary M.

2009-08-01

273

OPTIMUM BENTHIC MACROFAUNAL SAMPLING PROTOCOL FOR DETECTING DIFFERENCES BETWEEN FOUR HABITATS IN WILLAPA BAY, WASHINGTON, USA  

EPA Science Inventory

Abstract -- As part of an effort to estimate estuarine habitat values with respect to ecological indicators of benthic macrofaunal community condition, an optimal (effective and least costly) sampling protocol (sample unit size [area 3 depth], sieve mesh size, and sample number [...

274

Effectiveness of voluntary habitat stewardship in conserving grassland: case of operation burrowing owl in Saskatchewan.  

PubMed

There have been no published performance evaluations of nongovernmental, voluntary habitat stewardship programs. The Operation Burrowing Owl (OBO) stewardship program, initiated in 1987, was evaluated for its effectiveness in conservation of grassland habitat during 1986-1993. The 108 OBO sites from 1987 to 88 and 98 randomly selected non-OBO sites that were grassland in 1986 in the Regina-Weyburn, Saskatchewan study area were classified by size and agricultural soil suitability. By 1993, 41 (38%) of the 108 OBO sites had been withdrawn from the program. The 1986 area of grassland was compared with grassland area calculated from digitized 1993 LANDSAT imagery. A correction for satellite inaccuracies was determined. Grassland retention in 1993 was significantly higher at OBO sites (66%) than at random sites (49%), demonstrating that the OBO voluntary program effectively conserved habitat. Also, grassland retention was significantly lower on sites with better agricultural soils, and for sites <12 ha in size. Site type (OBO or random), size and their interaction, followed by agricultural soil suitability, had the greatest effects on grassland retention. During an era of accelerated grassland loss, OBO strongly and positively (statistically significant) affected conservation of grassland sites most at risk: sites <12 ha in size and with good to excellent agricultural soils. This suggests that grassland conservation efforts focus on vulnerable sites (small size and/or good agricultural soils) to provide nesting habitat for burrowing owls. Our study demonstrates that a voluntary stewardship program can significantly increase conservation of habitat. PMID:15037954

Warnock, Robert G; Skeel, Margaret A

2004-03-01

275

Climate Change Expands the Spatial Extent and Duration of Preferred Thermal Habitat for Lake Superior Fishes  

PubMed Central

Climate change is expected to alter species distributions and habitat suitability across the globe. Understanding these shifting distributions is critical for adaptive resource management. The role of temperature in fish habitat and energetics is well established and can be used to evaluate climate change effects on habitat distributions and food web interactions. Lake Superior water temperatures are rising rapidly in response to climate change and this is likely influencing species distributions and interactions. We use a three-dimensional hydrodynamic model that captures temperature changes in Lake Superior over the last 3 decades to investigate shifts in habitat size and duration of preferred temperatures for four different fishes. We evaluated habitat changes in two native lake trout (Salvelinus namaycush) ecotypes, siscowet and lean lake trout, Chinook salmon (Oncorhynchus tshawytscha), and walleye (Sander vitreus). Between 1979 and 2006, days with available preferred thermal habitat increased at a mean rate of 6, 7, and 5 days per decade for lean lake trout, Chinook salmon, and walleye, respectively. Siscowet lake trout lost 3 days per decade. Consequently, preferred habitat spatial extents increased at a rate of 579, 495 and 419 km2 per year for the lean lake trout, Chinook salmon, and walleye while siscowet lost 161 km2 per year during the modeled period. Habitat increases could lead to increased growth and production for three of the four fishes. Consequently, greater habitat overlap may intensify interguild competition and food web interactions. Loss of cold-water habitat for siscowet, having the coldest thermal preference, could forecast potential changes from continued warming. Additionally, continued warming may render more suitable conditions for some invasive species.

Cline, Timothy J.; Bennington, Val; Kitchell, James F.

2013-01-01

276

Effects of Frugivore Preferences and Habitat Heterogeneity on Seed Rain: A Multi-Scale Analysis  

PubMed Central

Seed rain mediated by frugivores is influenced by (1) the seed-deposition distances following fruit ingestion, (2) the disperser activity, as determined by its behaviour and habitat preferences, and (3) the structure of the habitat within the landscape. Here, we evaluated such components using the fleshy-fruited shrub Ephedra fragilis and the frugivorous Balearic lizard Podarcis lilfordi. We estimated seed-deposition patterns based on the displacements and habitat preferences of lizards, derived from visual surveys and telemetry data. The influence of variables potentially determining lizard habitat preference (i.e., height, slope, four measures of habitat abundance and four measures of habitat fragmentation) was evaluated at three spatial scales: ‘home-range’ (c. 2.5–10*103 m2; telemetry data), ‘within home-range’ (c. 100 m2; telemetry data) and ‘microhabitat’ (<100 m2; visual survey). Cumulative lizard displacement (from each telemetric location to the initial capture point) saturated before the peak of seed defecation (seed-retention time), indicating that lizard home-range size and habitat preferences were the main determinants of the spread and shape of seed shadows. Shrub cover was positively correlated with habitat preference at the three scales of analysis, whereas slope was negatively correlated at the home-range scale. Model scenarios indicated that spatially-aggregated seed rain emerged when we incorporated the joint effect of habitat preference at the two largest (home-range and within home-range) scales. We conclude that, in order to predict seed rain in animal dispersed plants, it is important to consider the multi-scale effects of habitat preference by frugivores.

Rodriguez-Perez, Javier; Larrinaga, Asier R.; Santamaria, Luis

2012-01-01

277

Influence of habitat amount, arrangement, and use on population trend estimates of male Kirtland's warblers  

USGS Publications Warehouse

Kirtland's warblers (Dendroica kirtlandii) persist in a naturally patchy environment of young, regenerating jack pine forests (i.e., 5-23 years old) created after wildfires and human logging activities. We examined how changing landscape structure from 26 years of forest management and wildfire disturbances influenced population size and spatial dispersion of male Kirtland's warblers within their restricted breeding range in northern Lower Michigan, USA. The male Kirtland's warbler population was six times larger in 2004 (1,322) compared to 1979 (205); the change was nonlinear with 1987 and 1994 identified as significant points of change. In 1987, the population trend began increasing after a slowly declining trend prior to 1987, and the rate of increase appeared to slow after 1994. Total amount of suitable habitat and the relative area of wildfire-regenerated habitat were the most important factors explaining population trend. Suitable habitat increased 149% primarily due to increasing plantations from forest management. The relative amount and location of wildfire-regenerated habitat modified the distribution of males among various habitat types, and the spatial variation in their abundance across the primary breeding range. These findings indicate that the Kirtland's warbler male population shifted its use of habitat types temporally and spatially as the population increased and as the relative availability of habitats changed through time. We demonstrate that researchers and managers need to consider not only habitat quality, but the temporal and the spatial context of habitat availability and population levels when making habitat restoration decisions. ?? 2008 Springer Science+Business Media B.V.

Donner, D. M.; Probst, J. R.; Ribic, C. A.

2008-01-01

278

Sandy beach surf zones: An alternative nursery habitat for 0-age Chinook salmon  

NASA Astrophysics Data System (ADS)

The role of each habitat fish use is of great importance to the dynamics of populations. During their early marine residence, Chinook salmon (Oncorhynchus tshawytscha), an anadromous fish species, mostly inhabit estuaries but also use sandy beach surf zones and the coastal ocean. However, the role of surf zones in the early life history of Chinook salmon is unclear. We hypothesized that surf zones serve as an alternative nursery habitat, defined as a habitat that consistently provides a proportion of a population with foraging and growth rates similar to those experienced in the primary nursery. First, we confirmed that juvenile Chinook salmon cohorts are simultaneously using both habitats by combining field collections with otolith chemical and structural analysis to directly compare size and migration patterns of juveniles collected in two Oregon (USA) estuaries and surf zones during three years. We then compared juvenile catch, diet and growth in estuaries and surf zones. Juveniles were consistently caught in both habitats throughout summer. Catches were significantly higher in estuaries (average ± SD = 34.3 ± 19.7 ind. 100 m-2) than surf zones (1.0 ± 1.5 ind. 100 m-2) and were positively correlated (r = 0.92). Size at capture (103 ± 15 mm fork length, FL), size at marine entry (76 ± 13 mm FL), stomach fullness (2 ± 2% body weight) and growth rates (0.4 ± 0.0 mm day-1) were similar between habitats. Our results suggest that when large numbers of 0-age Chinook salmon inhabit estuaries, juveniles concurrently use surf zones, which serve as an alternative nursery habitat. Therefore, surf zones expand the available rearing habitat for Chinook salmon during early marine residence, a critical period in the life history.

Marin Jarrin, J. R.; Miller, J. A.

2013-12-01

279

Survival and habitat of Ruffed Grouse nests in northern Michigan  

USGS Publications Warehouse

Effective management of Ruffed Grouse (Bonasa umbellus) populations requires a full understanding of chick production. Previous reports of nest survival for Ruffed Grouse are biased because they did not account for successful nests being more likely to be found, and the role of habitat quality in determining nest survival is unknown. We determined survival rates of Ruffed Grouse nests in northern lower Michigan using the less biased Mayfield estimator, defined differences between first and second nests, and compared the local habitat characteristics of successful and unsuccessful nests. Median hatching dates were 10 June for first nests (n = 34) and 1 July for second nests (n = 6). First nests had a lower survival rate (0.442, 95% CI = 0.270-0.716), a higher mean clutch size (12.7 eggs ?? 0.3 SE), and higher egg hatching rate (0.960, 95% CI = 0.900-0.997) than did second nests (nest survival = 0.788, 95% CI = 0.491-1.00; clutch size = 7.3 eggs ?? 0.3 SE; and hatching rate = 0.826, 95% CI = 0.718-0.925). Nest survival, annual production (3.4 hatchling females/adult female, 95% CI = 2.3-5.0), and fall recruitment (1.0 juvenile females/adult female, 95% CI = 0.3-2.4) were less than previously reported estimates. Habitat characteristics at nest sites varied widely and did not differ appreciably between successful and unsuccessful nests.

Larson, M. A.; Clark, M. E.; Winterstein, S. R.

2003-01-01

280

Habitat heterogeneity, species diversity and null models  

Microsoft Academic Search

The habitat heterogeneity hypothesis states that an increase in habitat heterogeneity leads to an increase in species diversity. We tested this hypothesis for a community of small mammals in the semiarid, sand-shinnery-oak ecosystem of the southwestern United States. We used indices of differentiation diversity to quantify differences between two habitat types (blowouts in a sand-shinnery-oak matrix) in terms of species

Michael J. Cramer; Michael R. Willig

2005-01-01

281

Comparing the nursery role of inner continental shelf and estuarine habitats for temperate marine fishes  

NASA Astrophysics Data System (ADS)

The marine-estuarine transition represents an important biogeographic boundary, yet juvenile marine finfish have been observed in both temperate inner continental shelf (ICS) and estuarine habitats during the summer nursery period. In a direct comparison of ICS and estuary nurseries, spatial and temporal patterns in species composition, biodiversity, size structure, and relative abundance of age-0 fishes were tested using contemporaneous data from multiyear (2004-2006) trawl surveys of the Maryland ICS near Assateague Island, MD, and lower Chesapeake Bay, VA (estuary). Survey data from both habitats showed similar seasonal progression of assemblage structure, biodiversity phenologies, and dominant species identities. Late summer densities for four of five numerically dominant species varied by habitat. Densities of bay anchovy Anchoa mitchilli, weakfish Cynoscion regalis, and Atlantic butterfish Peprilus triacanthus were higher in the ICS; whereas summer flounder Paralichthys dentatus density was higher in the estuary. Density of spot Leiostomus xanthurus did not differ between habitats. Apparent daily growth rates of these five species, as estimated by modal length progression, were not significantly different between the two habitats. Although individual species displayed varying affinities for ICS versus estuarine habitats, this study provides strong evidence that the ICS of the Middle Atlantic Bight is capable of functioning interchangeably with polyhaline estuarine regions as nursery habitat for a diverse group of marine finfish.

Woodland, Ryan J.; Secor, David H.; Fabrizio, Mary C.; Wilberg, Michael J.

2012-03-01

282

Response of the Agile Antechinus to Habitat Edge, Configuration and Condition in Fragmented Forest  

PubMed Central

Habitat fragmentation and degradation seriously threaten native animal communities. We studied the response of a small marsupial, the agile antechinus Antechinus agilis, to several environmental variables in anthropogenically fragmented Eucalyptus forest in south-east Australia. Agile antechinus were captured more in microhabitats dominated by woody debris than in other microhabitats. Relative abundances of both sexes were positively correlated with fragment core area. Male and female mass-size residuals were smaller in larger fragments. A health status indicator, haemoglobin-haematocrit residuals (HHR), did not vary as a function of any environmental variable in females, but male HHR indicated better health where sites' microhabitats were dominated by shrubs, woody debris and trees other than Eucalyptus. Females were trapped less often in edge than interior fragment habitat and their physiological stress level, indicated by the neutrophil/lymphocyte ratio in peripheral blood, was higher where fragments had a greater proportion of edge habitat. The latter trend was potentially due to lymphopoenia resulting from stress hormone-mediated leukocyte trafficking. Using multiple indicators of population condition and health status facilitates a comprehensive examination of the effects of anthropogenic disturbances, such as habitat fragmentation and degradation, on native vertebrates. Male agile antechinus' health responded negatively to habitat degradation, whilst females responded negatively to the proportion of edge habitat. The health and condition indicators used could be employed to identify conservation strategies that would make habitat fragments less stressful for this or similar native, small mammals.

Johnstone, Christopher P.; Lill, Alan; Reina, Richard D.

2011-01-01

283

Habitat fragmentation effects on birds in grasslands and wetlands: A critique of our knowledge  

USGS Publications Warehouse

Habitat fragmentation exacerbates the problem of habitat loss for grassland and wetland birds. Remaining patches of grasslands and wetlands may be too small, too isolated, and too influenced by edge effects to maintain viable populations of some breeding birds. Knowledge of the effects of fragmentation on bird populations is critically important for decisions about reserve design, grassland and wetland management, and implementation of cropland set-aside programs that benefit wildlife. In my review of research that has been conducted on habitat fragmentation, I found at least five common problems in the methodology used. The results of many studies are compromised by these problems: passive sampling (sampling larger areas in larger patches), confounding effects of habitat heterogeneity, consequences of inappropriate pooling of data from different species, artifacts associated with artificial nest data, and definition of actual habitat patches. As expected, some large-bodied birds with large territorial requirements, such as the northern harrier (Circus cyaneus), appear area sensitive. In addition, some small species of grassland birds favor patches of habitat far in excess of their territory size, including the Savannah (Passerculus sandwichensis), grasshopper (Ammodramus savannarum) and Henslow's (A. henslowii) sparrows, and the bobolink (Dolichonyx oryzivorus). Other species may be area sensitive as well, but the data are ambiguous. Area sensitivity among wetland birds remains unknown since virtually no studies have been based on solid methodologies. We need further research on grassland bird response to habitat that distinguishes supportable conclusions from those that may be artifactual.

Johnson, D. H.

2001-01-01

284

Habitat destruction, fragmentation, and disturbance promote invasion by habitat generalists in a multispecies metapopulation.  

PubMed

Species invasions are extremely common and are vastly outpacing the ability of resource agencies to address each invasion, one species at a time. Management actions that target the whole landscape or ecosystem may provide more cost-effective protection against the establishment of invasive species than a species-by-species approach. To explore what ecosystem-level actions might effectively reduce invasions, we developed a multispecies, multihabitat metapopulation model. We assume that species that successfully establish themselves outside their native range tend to be habitat generalists and that a tradeoff exists between competitive ability and habitat breadth, such that habitat specialists are competitively superior to habitat generalists. In this model, habitat destruction, fragmentation, and short-term disturbances all favor invasion by habitat generalists, despite the inferior competitive abilities of generalist species. Our model results illustrate that providing relatively undisturbed habitat and preventing further habitat degradation and fragmentation can provide a highly cost-effective defense against invasive species. PMID:15357806

Marvier, Michelle; Kareiva, Peter; Neubert, Michael G

2004-08-01

285

Habitat patterns in a small mammal community  

SciTech Connect

Microhabitat relationships between four sympatric small mammal species (Peromyscus leucopus, Ochrotomys nuttalli, Blarina brevicauda, and Tamias striatus) were examined to determine if their discriminant analysis of small mammal habitat represented a unique habitat utilization pattern for a specific small mammal community. The authors concluded that habitat is only one of many dimensions to be considered when studying the interactions of sympatric species. Reproductive strategy, activity patterns, and other factors make up the n-dimensional hyperspace of an animal's niche. Thus differences in habitat usage alone cannot be used to determine niche overlap and competition between species. (JMT)

Kitchings, J.T.; Levy, D.J.

1981-11-01

286

Elevation Derivatives for Mojave Desert Tortoise Habitat  

USGS Publications Warehouse

This report describes the methods used to derive various elevation-derivative grids that were inputted to the Mojave Desert Tortoise Habitat model (L. Gass and others, unpub. data). These grids, which capture information on surface roughness and topographic characteristics, are a subset of the environmental datasets evaluated for the tortoise habitat model. This habitat model is of major importance to the U.S. Fish and Wildlife Service, which is charged with management of this threatened population, including relocating displaced tortoises to areas identified as suitable habitat.

Wallace, Cynthia S. A.; Gass, Leila

2008-01-01

287

Accessible habitat: an improved measure of the effects of habitat loss and roads on wildlife populations  

Microsoft Academic Search

Habitat loss is known to be the main cause of the current global decline in biodiversity, and roads are thought to affect\\u000a the persistence of many species by restricting movement between habitat patches. However, measuring the effects of roads and\\u000a habitat loss separately means that the configuration of habitat relative to roads is not considered. We present a new measure

Felix Eigenbrod; Stephen J. Hecnar; Lenore Fahrig

2008-01-01

288

Disease, habitat fragmentation and conservation.  

PubMed Central

Habitat loss and the resultant fragmentation of remaining habitat is the primary cause of loss of biological diversity. How do these processes affect the dynamics of parasites and pathogens? Hess has provided some important insights into this problem using metapopulation models for pathogens that exhibit 'S-I' dynamics; for example, pathogens such as rabies in which the host population may be divided into susceptible and infected individuals. A major assumption of Hess's models is that infected patches become extinct, rather than recovering and becoming resistant to future infections. In this paper, we build upon this framework in two different ways: first, we examine the consequences of including patches that are resistant to infection; second, we examine the consequences of including a second species of host that can act as a reservoir for the pathogen. Both of these effects are likely to be important from a conservation perspective. The results of both sets of analysis indicate that the benefits of corridors and other connections that allow species to disperse through the landscape far outweigh the possible risks of increased pathogen transmission. Even in the commonest case, where harmful pathogens are maintained by a common reservoir host, increased landscape connectance still allows greater coexistence and persistence of a threatened or endangered host.

McCallum, Hamish; Dobson, Andy

2002-01-01

289

MEGAEPIFAUNA-HABITAT RELATIONSHIPS IN YAQUINA BAY, OR  

EPA Science Inventory

Habitat-based ecological risk assessments rely, in part, on estimates of the ecological value of the habitats at risk. As part of a larger programmatic effort to estimate estuarine habitat values, we determined megaepifauna-habitat relationships for four major intertidal habitat...

290

The influence of scale on salmon habitat restoration priorities  

Microsoft Academic Search

Habitat loss and alteration is the leading cause of species' declines world-wide, therefore habitat restoration and protection is a prominent conservation strategy. Despite obvious connections between habitat and threatened or endangered species, conservationists have been hard pressed explicitly to link abundance or population health with habitat attributes. Given that habitat relationships with species are often characterized at a spatial scale

Blake E. Feist; E. Ashley Steel; George R. Pess; Robert E. Bilby

2003-01-01

291

BENTHIC MACROFAUNA-HABITAT RELATIONSHIPS IN TWO PACIFIC NORTHWEST ESTUARIES  

EPA Science Inventory

Habitat-based ecological risk assessments rely, in part, on estimates of the ecological value of the habitats at risk. As part of a larger programmatic effort to estimate estuarine habitat values, we determined benthic macrofauna-habitat relationships for 8 intertidal habitats i...

292

Structural Definition and Mass Estimation of Lunar Surface Habitats for the Lunar Architecture Team Phase 2 (LAT-2) Study  

NASA Technical Reports Server (NTRS)

The Lunar Architecture Team Phase 2 study defined and assessed architecture options for a Lunar Outpost at the Moon's South Pole. The Habitation Focus Element Team was responsible for developing concepts for all of the Habitats and pressurized logistics modules particular to each of the architectures, and defined the shapes, volumes and internal layouts considering human factors, surface operations and safety requirements, as well as Lander mass and volume constraints. The Structures Subsystem Team developed structural concepts, sizing estimates and mass estimates for the primary Habitat structure. In these studies, the primary structure was decomposed into a more detailed list of components to be sized to gain greater insight into concept mass contributors. Structural mass estimates were developed that captured the effect of major design parameters such as internal pressure load. Analytical and empirical equations were developed for each structural component identified. Over 20 different hard-shell, hybrid expandable and inflatable soft-shell Habitat and pressurized logistics module concepts were sized and compared to assess structural performance and efficiency during the study. Habitats were developed in three categories; Mini Habs that are removed from the Lander and placed on the Lunar surface, Monolithic habitats that remain on the Lander, and Habitats that are part of the Mobile Lander system. Each category of Habitat resulted in structural concepts with advantages and disadvantages. The same modular shell components could be used for the Mini Hab concept, maximizing commonality and minimizing development costs. Larger Habitats had higher volumetric mass efficiency and floor area than smaller Habitats (whose mass was dominated by fixed items such as domes and frames). Hybrid and pure expandable Habitat structures were very mass-efficient, but the structures technology is less mature, and the ability to efficiently package and deploy internal subsystems remains an open issue.

Dorsey, John T.; Wu, K, Chauncey; Smith, Russell W.

2008-01-01

293

Evaluating the effects of protection on Paracentrotus lividus distribution in two contrasting habitats  

NASA Astrophysics Data System (ADS)

The sea urchin Paracentrotus lividus is common in the Mediterranean in shallow subtidal rocky habitats and in Posidonia oceanica beds. The aim of this study is to investigate whether protection has the same effect on the population structure of P. lividus occurring in rocky reef habitats and in P. oceanica beds. These results are important to generate hypotheses about the influence of human harvesting, predatory pressure and migration processes on P. lividus in the two habitats. Paracentrotus lividus was sampled at seven locations within the Gulf of Alghero (North West Sardinia) where the Capo Caccia-Isola Piana MPA (Marine Protected Area) is sited: 1 location was sited in Zone A, where no harvesting of P. lividus is allowed (NH), 3 locations were sited in Zone B, where harvesting is restricted (RH), and the other 3 were located outside the MPA where no restrictions apply to sea urchin harvesting (UH). For each combination of habitat × location, P. lividus density was assessed in 10 replicates using quadrats of 1 × 1 m and the size of 20 individuals (test diameter without spines) was measured. Finally, the specimens were grouped into size-classes to examine frequency distributions at each location. Sampling was performed at the end of the sea urchin harvesting period (April-May 2006). Analyses of data have highlighted significant variability among locations for both response variables. In both habitats, no differences were found in Paracentrotus lividus abundance among levels of protection (NH vs. RH vs. UH), while a significantly higher size was found in NH rather than in RH and UH locations. Differential direct and indirect effects of protection on P. lividus size is discussed. Also, P. lividus size seemed dependent on the habitat being quite larger in Posidonia oceanica than in the rocky reefs. This finding suggests that settlement and recruitment could be more highly successful events in rocky habitats, and that in P. oceanica meadows large-sized immigrants coming from the rocky habitat contribute to the population structure. The need to define the role of the P. oceanica habitat is also discussed.

Ceccherelli, G.; Pinna, S.; Sechi, N.

2009-01-01

294

Distribution of field sizes in a petroleum system: parabolic fractal, lognormal or stretched exponential?  

Microsoft Academic Search

Field size distributions in three Petroleum Systems have been analyzed using different approaches. The parabolic fractal model shows the Niger delta and the Gulf of Mexico (GOM) Outer Continental Shelf (OCS) have similar dispersed habitats, in contrast to the Saharan Triassic, which has a concentrated habitat. On a lognormal model, the Niger delta and the Saharan Triassic field size distributions

Jean Laherrere

2000-01-01

295

Squirrel monkeys ( Saimiri ) in natural habitats in Panama, Colombia, Brazil, and Peru  

Microsoft Academic Search

Troops ofSaimiri (squirrel monkeys) were observed in 31 locations in natural habitats in Panama, Colombia, Brazil, and Peru. Troop size varied from 10 to 35 animals in Panama and Colombia and from 120 to 300 or more in the unaltered rainforests of Amazonia. Troop size correlated with forest size in all areas.Saimiri associated withCebus (capuchin monkeys) in several areas.Saimiri troops

John D. Baldwin; Janice I. Baldwin

1971-01-01

296

Habitat Use by Fishes in Coral Reefs, Seagrass Beds and Mangrove Habitats in the Philippines  

PubMed Central

Understanding the interconnectivity of organisms among different habitats is a key requirement for generating effective management plans in coastal ecosystems, particularly when determining component habitat structures in marine protected areas. To elucidate the patterns of habitat use by fishes among coral, seagrass, and mangrove habitats, and between natural and transplanted mangroves, visual censuses were conducted semiannually at two sites in the Philippines during September and March 2010–2012. In total, 265 species and 15,930 individuals were recorded. Species richness and abundance of fishes were significantly higher in coral reefs (234 species, 12,306 individuals) than in seagrass (38 species, 1,198 individuals) and mangrove (47 species, 2,426 individuals) habitats. Similarity tests revealed a highly significant difference among the three habitats. Fishes exhibited two different strategies for habitat use, inhabiting either a single (85.6% of recorded species) or several habitats (14.4%). Some fish that utilized multiple habitats, such as Lutjanus monostigma and Parupeneus barberinus, showed possible ontogenetic habitat shifts from mangroves and/or seagrass habitats to coral reefs. Moreover, over 20% of commercial fish species used multiple habitats, highlighting the importance of including different habitat types within marine protected areas to achieve efficient and effective resource management. Neither species richness nor abundance of fishes significantly differed between natural and transplanted mangroves. In addition, 14 fish species were recorded in a 20-year-old transplanted mangrove area, and over 90% of these species used multiple habitats, further demonstrating the key role of transplanted mangroves as a reef fish habitat in this region.

Honda, Kentaro; Nakamura, Yohei; Nakaoka, Masahiro; Uy, Wilfredo H.; Fortes, Miguel D.

2013-01-01

297

Assessing alternative anthropogenic habitats for conserving waterbirds: salinas as buffer areas against the impact of natural habitat loss for shorebirds  

Microsoft Academic Search

Because many natural waterbird habitats are threatened by human disturbance and sea level rise, it is vitally important to identify alternative wetlands that may supplement declining natural habitats. Coastal salinas are anthropogenic habitats used for obtaining salt by evaporation of sea water. These habitats support important numbers of waterbirds around the world, but their importance as feeding habitats is poorly

JOSE A. MASERO ´ ´

2003-01-01

298

Endolithic Microbial Communities in Polar Desert Habitats  

Microsoft Academic Search

Microorganisms inhabiting terrestrial endolithic habitats are widespread in polar environments including the Antarctic Dry Valleys and the Canadian high Arctic. Their ability to survive in these harsh environments is a result of their finding protection from extremes in temperature, aridity, radiation and winds by colonizing nutrient-rich subsurface habitats that provide more amenable conditions for growth, often developing as vertically stratified

Christopher R. Omelon

2008-01-01

299

PRINCIPAL COMPONENT ANALYSIS OF WOODPECKER NESTING HABITAT  

Microsoft Academic Search

Biologists have long been able to associate species of birds in a general way, with their characteristic habitats. Yet, for most species few such studies of a quantitative nature have been published. James (1971) used principal component and discriminant function analyses to ordinate breeding habitats of 46 species of breeding birds in Arkansas on vegetational continua. These kinds of analyses

RICIIAKD N. COIVNER; CUKTIS S. ADKISSON

1977-01-01

300

Adaptive Management in Habitat Conservation Plans  

Microsoft Academic Search

Habitat conservation plans (HCPs) allow incidental take of threatened or endangered species in exchange for conservation measures that minimize and mitigate such taking. Habitat conservation plans en- tail a compromise between regulatory certainty and scientific uncertainty. This compromise is controversial because many HCPs are thought to inadequately address scientific uncertainty. Adaptive management is the systematic acquisition and application of reliable

George F. Wilhere

2002-01-01

301

Habitat Management for Birds of West Virginia.  

National Technical Information Service (NTIS)

This report is a synthesis of existing literature and survey data for West Virginia birds. The objectives of this report are to summarize available bird population data for major habitat types in West Virginia, to indicate how changes in habitat influence...

S. H. Anderson C. S. Robbins J. R. Partelow

1981-01-01

302

Habitat Management Guides for Birds of Prey.  

National Technical Information Service (NTIS)

Habitat management for raptors may mean (1) the manipulation of uses and activities in an area so that raptors will be either benefitted or at least not seriously affected, or (2) the physical change of development of the habitat such that it is more suit...

M. Call

1979-01-01

303

Robotic Precursor Missions for Mars Habitats  

Microsoft Academic Search

Infrastructure support for robotic colonies, manned Mars habitat, and\\/or robotic exploration of planetary surfaces will need to rely on the field deployment of multiple robust robots. This support includes such tasks as the deployment and servicing of power systems and ISRU generators, construction of beaconed roadways, and the site preparation and deployment of manned habitat modules. The current level of

Terry Huntsberger; Paolo Pirjanian; Paul S. Schenker; Ashitey Trebi-Ollennu; Hari Das; Sajay Joshi

2000-01-01

304

Habitat Suitability Index Models: Fox Squirrel.  

National Technical Information Service (NTIS)

Habitat preferences and species characteristics of the fox squirrel(Sciurus niger) are described in this publication. It is one of a series of Habitat Suitability Index (HSI) models and was developed through an analysis of available scientific data on the...

A. W. Allen

1982-01-01

305

HABITAT MODELING APPROACHES FOR RESTORATION SITE SELECTION  

EPA Science Inventory

Numerous modeling approaches have been used to develop predictive models of species-environment and species-habitat relationships. These models have been used in conservation biology and habitat or species management, but their application to restoration efforts has been minimal...

306

COASTAL SUBMERGED VEGETATION: AQUATIC HABITAT RESEARCH  

EPA Science Inventory

Aquatic vegetation is one of the most widespread and important types of aquatic habitat, in part because of the exceptional productivity of the plants. Aquatic vegetation also strongly influences local physical and chemical habitat conditions of significance to fish and shellfis...

307

Dispersal capacity and diet breadth modify the response of wild bees to habitat loss  

PubMed Central

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z = 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z = 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.

Bommarco, Riccardo; Biesmeijer, Jacobus C.; Meyer, Birgit; Potts, Simon G.; Poyry, Juha; Roberts, Stuart P. M.; Steffan-Dewenter, Ingolf; Ockinger, Erik

2010-01-01

308

L-Reactor Habitat Mitigation Study  

SciTech Connect

The L-Reactor Fish and Wildlife Resource Mitigation Study was conducted to quantify the effects on habitat of the L-Reactor restart and to identify the appropriate mitigation for these impacts. The completed project evaluated in this study includes construction of a 1000 acre reactor cooling reservoir formed by damming Steel Creek. Habitat impacts identified include a loss of approximately 3,700 average annual habitat units. This report presents a mitigation plan, Plan A, to offset these habitat losses. Plan A will offset losses for all species studied, except whitetailed deer. The South Carolina Wildlife and Marine Resources Department strongly recommends creation of a game management area to provide realistic mitigation for loss of deer habitats. 10 refs., 5 figs., 3 tabs. (MHB)

Not Available

1988-02-01

309

POWER TO DETECT REGIONAL TRENDS IN HABITAT CHARACTERISTICS  

EPA Science Inventory

The condition of stream habitat draws considerable attention concerning the protection and recovery of salmonid populations in the West. Habitat degradation continues and substantial sums of money are spent on habitat restoration. However, aided by uncertainty concerning the ad...

310

POWER TO DETECT REGIONAL TRENDS IN PHYSICAL HABITAT  

EPA Science Inventory

The condition of stream habitat draws considerable attention concerning the protection and recovery of salmonid populations in the West. Habitat degradation continues and substantial sums of money are spent on habitat restoration. However, aided by uncertainty concerning the ad...

311

Assessing patterns of fish demographics and habitat in stream networks  

EPA Science Inventory

Effective habitat restoration planning requires correctly anticipating demographic responses to altered habitats. New applications of Passive Integrated Transponder (PIT) tag technology to fish-habitat research have provided critical insights into fish movement, growth, and surv...

312

50 CFR 660.75 - Essential Fish Habitat (EFH).  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Essential Fish Habitat (EFH). 660.75 Section 660.75...Coast Groundfish Fisheries § 660.75 Essential Fish Habitat (EFH). Essential fish habitat (EFH) is defined as those waters...

2013-10-01

313

Teaching through Trade Books: A Habitat Is a Home  

NSDL National Science Digital Library

We all have our own habitats, and this month students spend time thinking about what other organisms need to survive, what types of habitats they live in, and how to set up a habitat for a classroom animal.

Royce, Christine A.

2009-09-01

314

50 CFR 226.207 - Critical habitat for leatherback turtle.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Critical habitat for leatherback turtle. 226.207 Section 226.207 Wildlife...HABITAT § 226.207 Critical habitat for leatherback turtle. Leatherback Sea Turtle (dermochelys coriacea ) The...

2010-10-01

315

50 CFR 226.207 - Critical habitat for leatherback turtle.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Critical habitat for leatherback turtle. 226.207 Section 226.207 Wildlife...HABITAT § 226.207 Critical habitat for leatherback turtle. Leatherback Sea Turtle (dermochelys coriacea ) The...

2009-10-01

316

An Initial Mars Habitat (IMH)  

NASA Astrophysics Data System (ADS)

As long duration, manned missions to Mars are studied for feasibility, the requirements to maintain a crew for two years in hostile environments while allowing productive and necessary work to occur, quickly becomes a driving force. Based on a mission scenario developed in the Explorations Program Office at the Johnson Space, the Initial Mars Habitat (IMH) explores one solution to providing a six person crew with the necessary hardware, logistics and environment to support a 500 day Martian surface stay. Many key issues drove the development of this initial concept; crew safety, logistics resupply, crew productivity and several critical mission element assumptions such as the limitations of a surface lander. Consideration of expansion beyond the first mission to an enhanced capability base was also integrated into the development of the IMH.

Gutierrez, D. J.

1993-02-01

317

Toward a simple, DEM-based model for linking channel morphology with Atlantic salmon habitat  

NASA Astrophysics Data System (ADS)

Atlantic salmon require swiftwater gravel-bedded rivers for rearing and spawning. Morphology of the rivers in coastal New England and Atlantic Canada is strongly influenced by glacial and land-use history. Longitudinal profiles are characterized by relatively steep (gradient >0.002) and flat (gradient <0.0005) segments, with length scales of several km. This heterogeneity corresponds to strong variations in channel form (boulder cascades, pools and riffles, plane beds, low-gradient wetlands, mainstem lakes), substrate grain size, and aquatic habitat characteristics. We seek to develop methods to use simple GIS-based measurements to investigate relationships between channel processes and habitat characteristics. The near extirpation of Atlantic salmon from U.S. rivers motivates restoration efforts, including the removal of barriers to migration and instream habitat restoration projects. Resource managers desire GIS-based methods to facilitate rapid identification of potential spawning and rearing habitat within channel networks. We develop methods for predicting channel conditions using traditional (10-30 m pixels) and lidar (1-m pixels) digital elevation models (DEMs). We calibrate and test our methods using field surveys of habitat, channel form and bed grain size in coastal Maine and New Brunswick. A statistical approach uses stream gradient measured over segments defined by channel centerline intersections with contour lines (3-6 m intervals) on digitized topographic maps, contributing area, and physiographic province. This model explains 73% of the variation in field-identified rearing habitat. Commonly available GIS data allows this model to be applied over large areas, making it useful for regional habitat assessments. We present preliminary results from a process- based model that predicts bed grain size using morphologic measurements from lidar DEMs and the Shields equation. We compare these predictions to field grain size and habitat mapping. The lidar-based method has similar predictive capability to the statistical model, and greater spatial resolution (channel gradient is measured over 0.5-m vertical intervals). We suggest that failures in the lidar-based approach likely relate to local variations in channel roughness and sediment size and supply not included in the model. Further, we speculate that these mismatches may present an opportunity to prioritize stream restoration efforts such as removal of small dams or additions of large woody debris by identifying river reaches with potential high- quality habitat.

Snyder, N. P.; Wilkins, B. C.; Wright, J. R.

2008-12-01

318

Subseafloor basalts as fungal habitats  

NASA Astrophysics Data System (ADS)

The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, still we lack substantial information about the abundance, diversity, and consequence of its biosphere. The last two decades have involved major research accomplishments within this field and a change in view of the ocean crust and its potential to harbour life. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (∼50-200 µm in diameter) body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate-forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few µm to ∼20 µm in diameter) are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma.

Ivarsson, M.

2012-09-01

319

Habitat distribution for non-native Amazona viridigenalis within San Diego County using Maxent predictive model  

NASA Astrophysics Data System (ADS)

Human propagated changes to the environment have adversely affected certain species while advantaging other species. Psittacines, or species that fall within the parrot family, have been found to be well adapted to modified environments. Over time, transportation of various parrot species for use in the exotic pet trade has caused accidental releases of individual parrots, resulting in species groups forming and colonizing in new, non-native environments, specifically urban and suburban ones. Amazona viridigenalis, the Red-crowned parrot, is a species that has adapted to living in several regions within the United States including Texas, Florida, and California. This species is endangered within its native range in the lowlands of eastern Mexico, yet has the largest population of any other psittacine species in California. Despite this interesting dichotomy this species remains severely understudied in its new range. Using geographic information systems and Maxent predictive model, this research aims to achieve a greater understanding of the extent of habitat suitable to the Amazona viridigenalis within San Diego County and the habitat variables that enable its establishment success. Presence locations where individuals of the species were using habitat were collected along with 12 important variables that represent Red-crowned parrot habitat elements. These were used in the creation of a predictive habitat model utilizing Maxent machine-learning technique. Three models were created using three different background extents from which the pseudo-absence points were generated. These models were tested for statistical significance and predictive accuracy. It was found that model performance significantly decreased with a decrease in size of model extent. The largest extent was chosen to model habitat using the five variables that were found to be the least correlated, achieved the most gain, and had the most explanatory power for the earlier models. The final model generated depicts highly suitable habitat for A. viridigenalis along the entire coast of San Diego County with pockets of moderately suitable to highly suitable habitat infiltrating into the interior. Some locations in East County were also identified as having moderate habitat suitability. It was found that A. viridigenalis requires habitat with elevations between sea level and 200 m., slopes of zero to 11% grade, and large amounts of non-native vegetated ground cover. More suitable habitat was found at locations with moderate to high population density and in close proximity to roads, suggesting the importance of human-presence in shaping habitat for A. viridigenalis.

Meseck, Kristin April

320

SKYLAB II - Making a Deep Space Habitat from a Space Launch System Propellant Tank  

NASA Technical Reports Server (NTRS)

Called a "House in Space," Skylab was an innovative program that used a converted Saturn V launch vehicle propellant tank as a space station habitat. It was launched in 1973 fully equipped with provisions for three separate missions of three astronauts each. The size and lift capability of the Saturn V enabled a large diameter habitat, solar telescope, multiple docking adaptor, and airlock to be placed on-orbit with a single launch. Today, the envisioned Space Launch System (SLS) offers similar size and lift capabilities that are ideally suited for a Skylab type mission. An envisioned Skylab II mission would employ the same propellant tank concept; however serve a different mission. In this case, the SLS upper stage hydrogen tank is used as a Deep Space Habitat (DSH) for NASA s planned missions to asteroids, Earth-Moon Lagrangian point and Mars.

Griffin, Brand N.; Smitherman, David; Kennedy, Kriss J.; Toups, Larry; Gill, Tracy; Howe, A. Scott

2012-01-01

321

Breeding habitat expansion in the Grey heron ( Ardea cinerea)  

NASA Astrophysics Data System (ADS)

Predicting the response of natural populations to habitat loss and the ecological consequences to communities is one of the great challenges of ecology. Here, we report long-term (30 years) results from an ecological survey illustrating a change of breeding habits in the Grey heron, Ardea cinerea. Comparative data on brood size show that Grey herons adopting a new breeding behaviour produce more nestlings than other individuals in the modified area. Interestingly, this recent behavioural change may result in indirect effects on the community structure by negatively affecting the breeding population of the Purple heron Ardea purpurea.

Thomas, Frédéric; Hafner, Heinz

2000-03-01

322

Disentangling habitat capacity from dendritic connectivity in river-like landscapes  

NASA Astrophysics Data System (ADS)

Habitat fragmentation and land use changes are causing major biodiversity losses. Connectivity of the landscape or environmental conditions alone can shape biodiversity patterns. In nature, however, local habitat characteristics are often intrinsically linked to a specific connectivity. Such a link is evident in riverine ecosystems, where hierarchical dendritic structures command related scaling on habitat capacity. We experimentally disentangled the effect of local habitat capacity (i.e., the patch-size) and dendritic connectivity on biodiversity in aquatic microcosm metacommunities by suitably arranging patch-sizes (Riverine, Random and Homogeneous, fig. 1) within river-like networks. By measuring species' persistence and species' density we followed diversity patterns in terms of alpha-, beta-, gamma-diversity (local species richness, among-community dissimilarity and regional species richness), and community evenness in the above landscape configurations. Overall, more connected communities that occupy a central position in the network exhibited higher species richness, irrespective of patch-size arrangement. High regional evenness in community composition was found only in landscapes preserving geomorphological scaling properties of patch-sizes. In these landscapes, some of the rarer species sustained regionally more abundant populations and were better able to track their own niche requirements compared to landscapes with homogeneous patch size or landscapes with spatially uncorrelated patch size. Altering the natural link between dendritic connectivity and patch-size strongly affects community composition and population persistence at multiple scales. All the experimental results were supported (and extended by) a theoretical analysis where the above mechanisms have been generalized. Spatial configuration of dendritic networks and corresponding patch-sizes in the microcosm experiment. (A) Riverine landscapes (blue) preserved the observed scaling properties of real river basins; (B) Random landscapes (red) had the exact values of volumes as in the Riviverine landscapes, randomly distributed across the networks; (C), in homogeneous landscapes (green) the total volume of the whole metacommunity was equally distributed to each 36 local communities. Patch-size (size of the circle) is scaled to the actual medium volume.

Carrara, F.; Rinaldo, A.; Giometto, A.; Altermatt, F.

2013-12-01

323

Developing a Habitat for Long Duration, Deep Space Missions  

NASA Technical Reports Server (NTRS)

One possible next leap in human space exploration is a mission to a near Earth asteroid (NEA). In order to achieve such an ambitious goal, a space habitat will need to be designed to accommodate a crew of four for the 380-day round trip. The Human Spaceflight Architecture Team (HAT) developed a conceptual design for such a habitat. The team identified activities that would be performed inside a long-duration, deep space habitat, and the capabilities needed to support such a mission. A list of seven functional activities/capabilities was developed: individual and group crew care, spacecraft and mission operations, subsystem equipment, logistics and resupply, and contingency operations. The volume for each activity was determined using NASA STD-3001 and the companion Human Integration Design Handbook (HIDH). Although, the sum of these volumes produced an over-sized spacecraft, the team evaluated activity frequency and duration to identify functions that could share a common volume without conflict, reducing the total volume by 24%. After adding 10% for growth, the resulting functional pressurized volume was calculated to be 268 m3 distributed over the functions. The work was validated through comparison with the International Space Station (ISS), Bigelow Aerospace s proposed habitat module, and NASA s Trans-Hab concepts. In the end, the team developed an internal layout that (a) minimized the transit time between related crew stations, (b) accommodated expected levels of activity at each station, (c) isolated stations when necessary for health, safety, performance, and privacy, and (d) provided a safe, efficient, and comfortable work and living environment.

Rucker, Michelle A.; Thompson, Shelby

2011-01-01

324

Developing a Habitat for Long Duration, Deep Space Missions  

NASA Technical Reports Server (NTRS)

One possible next leap in human space exploration for the National Aeronautics and Space Administration (NASA) is a mission to a near Earth asteroid (NEA). In order to achieve such an ambitious goal, a space habitat will need to accommodate a crew of four for the 380-day round trip. The Human Spaceflight Architecture Team (HAT) developed a conceptual design for such a habitat. The team identified activities that would be performed inside a long-duration, deep space habitat, and the capabilities needed to support such a mission. A list of seven functional activities/capabilities was developed: individual and group crew care, spacecraft and mission operations, subsystem equipment, logistics and resupply, and contingency operations. The volume for each activity was determined using NASA STD-3001 and the companion Human Integration Design Handbook (HIDH). Although, the sum of these volumes produced an over-sized spacecraft, the team evaluated activity frequency and duration to identify functions that could share a common volume without conflict, reducing the total volume by 24%. After adding 10% for growth, the resulting functional pressurized volume was calculated to be a minimum of 268 cu m (9,464 cu ft) distributed over the functions. The work was validated through comparison to Mir, Skylab, the International Space Station (ISS), Bigelow Aerospace s proposed habitat module, and NASA s Trans-Hab concept. Using HIDH guidelines, the team developed an internal layout that (a) minimized the transit time between related crew stations, (b) accommodated expected levels of activity at each station, (c) isolated stations when necessary for health, safety, performance, and privacy, and (d) provided a safe, efficient, and comfortable work and living environment.

Rucker, Michelle A.; Thompson, Shelby

2012-01-01

325

Estimated home ranges can misrepresent habitat relationships on patchy landscapes  

USGS Publications Warehouse

Home ranges of animals are generally structured by the selective use of resource-bearing patches that comprise habitat. Based on this concept, home ranges of animals estimated from location data are commonly used to infer habitat relationships. Because home ranges estimated from animal locations are largely continuous in space, the resource-bearing patches selected by an animal from a fragmented distribution of patches would be difficult to discern; unselected patches included in the home range estimate would bias an understanding of important habitat relationships. To evaluate potential for this bias, we generated simulated home ranges based on optimal selection of resource-bearing patches across a series of simulated resource distributions that varied in the spatial continuity of resources. For simulated home ranges where selected patches were spatially disjunct, we included interstitial, unselected cells most likely to be traveled by an animal moving among selected patches. We compared characteristics of the simulated home ranges with and without interstitial patches to evaluate how insights derived from field estimates can differ from actual characteristics of home ranges, depending on patchiness of landscapes. Our results showed that contiguous home range estimates could lead to misleading insights on the quality, size, resource content, and efficiency of home ranges, proportional to the spatial discontinuity of resource-bearing patches. We conclude the potential bias of including unselected, largely irrelevant patches in the field estimates of home ranges of animals can be high, particularly for home range estimators that assume uniform use of space within home range boundaries. Thus, inferences about the habitat relationships that ultimately define an animal's home range can be misleading where animals occupy landscapes with patchily distributed resources.

Mitchell, M. S.; Powell, R. A.

2008-01-01

326

Interpretation of landscape pattern and habitat change for local indicator species using satellite imagery and geographic information system data in New Brunswick, Canada  

Microsoft Academic Search

We measured the extent and rate of habitat change and interpreted landscape metrics for fragmentation in the Fundy Model Forest, New Brunswick, from 1993 to 1999 using geographical information system baseline data up- dated with landscape changes detected on Landsat satellite imagery. We report on three categories of landscape metrics (habitat cover, patch size, and nearest neighbour), which we interpret

Matthew G. Betts; Steven E. Franklin; Ron G. Taylor

2003-01-01

327

A Tool for the Automated Design and Evaluation of Habitat Interior Layouts  

NASA Technical Reports Server (NTRS)

The objective of space habitat design is to minimize mass and system size while providing adequate space for all necessary equipment and a functional layout that supports crew health and productivity. Unfortunately, development and evaluation of interior layouts is often ignored during conceptual design because of the subjectivity and long times required using current evaluation methods (e.g., human-in-the-loop mockup tests and in-depth CAD evaluations). Early, more objective assessment could prevent expensive design changes that may increase vehicle mass and compromise functionality. This paper describes a new interior design evaluation method to enable early, structured consideration of habitat interior layouts. This interior layout evaluation method features a comprehensive list of quantifiable habitat layout evaluation criteria, automatic methods to measure these criteria from a geometry model, and application of systems engineering tools and numerical methods to construct a multi-objective value function measuring the overall habitat layout performance. In addition to a detailed description of this method, a C++/OpenGL software tool which has been developed to implement this method is also discussed. This tool leverages geometry modeling coupled with collision detection techniques to identify favorable layouts subject to multiple constraints and objectives (e.g., minimize mass, maximize contiguous habitable volume, maximize task performance, and minimize crew safety risks). Finally, a few habitat layout evaluation examples are described to demonstrate the effectiveness of this method and tool to influence habitat design.

Simon, Matthew A.; Wilhite, Alan W.

2013-01-01

328

Habitat-Specific Morphological Variation among Threespine Sticklebacks (Gasterosteus aculeatus) within a Drainage Basin  

PubMed Central

Habitat-specific morphological variation, often corresponding to resource specialization, is well documented in freshwater fishes. In this study we used landmark based morphometric analyses to investigate morphological variation among threespine sticklebacks (Gasterosteus aculeatus L.) from four interconnected habitat types within a single lowland drainage basin in eastern England. These included the upper and lower reaches of the river, the estuary, a connected ditch network and a coastal salt marsh. We found significant habitat-specific differences in morphology, with three axes of variation describing differences in orbit diameter, body depth, caudal peduncle shape and pectoral fin positioning as well as variation in relative dorsal and pelvic spine size. Interestingly, the ditch system, an artificial and heavily managed habitat, is populated by sticklebacks with a characteristic morphology, suggesting that human management of habitats can in some circumstances lead to morphological variation among the animals that inhabit them. We discuss the mechanisms that conceivably underlie the observed morphological variation and the further work necessary to identify them. Finally, we consider the implications of habitat-specific body shape variation for the behavioural ecology of this ecologically generalist species.

Webster, Mike M.; Atton, Nicola; Hart, Paul J. B.; Ward, Ashley J. W.

2011-01-01

329

Spatial use and habitat associations of Columbian white-tailed deer fawns in southwestern Oregon  

USGS Publications Warehouse

Fawns represent a critical life history stage in the dynamics of deer populations, yet little recent information is available on the ecology of neonatal Columbian white-tailed deer (CWTD), a geographically isolated and federally endangered sub-species. We described home ranges, areas of concentrated use, and habitat associations of CWTD fawns in southwestern Oregon during the summers of 1997 and 1998. Spatial use patterns and habitat use within areas of concentrated use were described for 11 radio-marked fawns. Pooled habitat use was described for 24 radio-marked fawns. Areas of concentrated use averaged 2.4 ha, which was 13.3% of mean 95% home range size (18.0 ha). Frequent use of oak-madrone woodland and riparian cover types characterized fawn habitat use patterns. Cover types containing conifers were rarely used and usually not available within home ranges. Although we found no detectable patterns of habitat selection or avoidance among fawns, areas of concentrated use were composed mostly of oak-madrone woodland (35%) and riparian (26%) cover types. Moreover, 74% of concentrated use area was within 200 m of streams. Our results provide useful information on habitat characteristics used frequently by CWTD fawns.

Ricca, M. A.; Anthony, R. G.; Jackson, D. H.; Wolfe, S. A.

2003-01-01

330

Annual variation in the distribution, abundance, and habitat response of the palila (Loxioides bailleui)  

USGS Publications Warehouse

We studied the distribution, population size, and habitat response of the Palila (Loxioides bailleui) during the 1980-1984 nonbreeding seasons to infer factors that limit the population and to develop management strategies. Distribution was fairly constant from year to year. Palila were confined to the subalpine woodland on Mauna Kea on the island of Hawaii, occurred between 2,000 and 2,850 m elevation, and reached highest densities on the southwests lopes. The population showed large annual fluctuations from 6,400 birds in 1981 to 2,000 in 1984. The width of woodland was the most important variable in determining habitat response. Palila were more common in areas with greater crown cover, taller trees, and a higher proportion of native plants in the understory. Annual variation in Palila density within a habitat reflected variation in levels of their staple food, mamane pods. The main limiting factors of the population appeared to be the availability of good habitat and levels of their staple food. Palila had strongly depressed densities in the Pohakuloa flats area. This low density could not be explained by gross habitat features or food levels. Site tenacity, thermal stress, disturbance, and disease were hypothesized explanations. Our study indicated that the most effective management strategies would be the removal of feral ungulates and certain noxious plants from Palila habitat and the extension of the woodland zone to areas now intensively grazed

Scott, J.M.; Mountainspring, S.; Van Riper, C. , III; Kepler, C.B.; Jacobi, J.D.; Burr, T.A.; Giffen, J.G.

1984-01-01

331

Class Size.  

ERIC Educational Resources Information Center

After a brief introduction identifying current issues and trends in research on class size, this brochure reviews five recent studies bearing on the relationship of class size to educational effectiveness. Part 1 is a review of two interrelated and highly controversial "meta-analyses" or statistical integrations of research findings on class size,…

Ellis, Thomas I.

1985-01-01

332

Selecting habitat management strategies on refuges  

USGS Publications Warehouse

This report is a joint effort of the Biological Resources Division, U.S. Geological Survey and the U.S. Fish and Wildlife Service (FWS) to provide National Wildlife Refuge (NWR) managers guidance on the selection and evaluation of habitat management strategies to meet stated objectives. The FWS recently completed a handbook on writing refuge management goals and objectives (U.S. Fish and Wildlife Service 1996a). the National Wildlife Refuge System Improvement Act of 1997 requires that National Wildlife Refuge System (NWRS) lands be managed according to approved Comprehensive Conservation Plans to guide management decisions and devise strategies for achieving refuge unit purposes and meeting the NWRS mission. It is expected that over the next several years most refuges will develop new or revised refuge goals and objectives for directing their habitat management strategies. This paper outlines the steps we recommend in selecting and evaluating habitat management strategies to meet specific refuge habitat objectives. We selected two examples to illustrate the process. Although each refuge is unique and will require specific information and solutions, these two examples can be used as guidance when selecting and evaluating habitat management strategies for other refuge resources: Example 1. Management of floodplain woods habitat for forest interior birds. The biological recourse of concern is the quality and quantity of floodplain woods habitat for eastern forest interior birds in the Cypress Creek NWR (U.S. Fish and Wildlife Service 1996b). Example 2. Management of habitat for biodiversity: Historical landscape proportions. The biological resource of concern is the change in diversity associated with man-induced changes in the distribution and abundance of habitat types at the Minnesota Valley NWR (U.S. Fish and Wildlife Service 1996c).

Schroeder, Richard L.; King, Wayne J.; Cornely, John E.

1998-01-01

333

Gulf of Maine Marine Habitat Primer  

NSDL National Science Digital Library

This book provides an overview of the Gulf of Maine's coastal and offshore habitats for resource managers and other coastal decision-makers in government, Non-Government Organizations (NGOs), and the private sector. Illustrated with color photographs and drawings, the primer describes habitat characteristics, ecological functions, economic and recreational values, human impacts, and management considerations. It is intended as a tool for resource managers, planners, legislators, conservation commissioners, NGO staff members, and other people seeking a better understanding of marine habitats from Massachusetts to Nova Scotia. The book is available in six downloadable sections, or it can be ordered as a hard copy.

334

Classification of immature mosquito species according to characteristics of the larval habitat in the subtropical province of Chaco, Argentina.  

PubMed

To classify mosquito species based on common features of their habitats, samples were obtained fortnightly between June 2001-October 2003 in the subtropical province of Chaco, Argentina. Data on the type of larval habitat, nature of the habitat (artificial or natural), size, depth, location related to sunlight, distance to the neighbouring houses, type of substrate, organic material, vegetation and algae type and their presence were collected. Data on the permanence, temperature, pH, turbidity, colour, odour and movement of the larval habitat's water were also collected. From the cluster analysis, three groups of species associated by their degree of habitat similarity were obtained and are listed below. Group 1 consisted of Aedes aegypti. Group 2 consisted of Culex imitator, Culex davisi, Wyeomyia muehlensi and Toxorhynchites haemorrhoidalis separatus. Within group 3, two subgroups are distinguished: A (Psorophora ferox, Psorophora cyanescens, Psorophora varinervis, Psorophora confinnis, Psorophora cingulata, Ochlerotatus hastatus-oligopistus, Ochlerotatus serratus, Ochlerotatus scapularis, Culex intrincatus, Culex quinquefasciatus, Culex pilosus, Ochlerotatus albifasciatus, Culex bidens) and B (Culex maxi, Culex eduardoi, Culex chidesteri, Uranotaenia lowii, Uranotaenia pulcherrima, Anopheles neomaculipalpus, Anopheles triannulatus, Anopheles albitarsis, Uranotaenia apicalis, Mansonia humeralis and Aedeomyia squamipennis). Principal component analysis indicates that the size of the larval habitats and the presence of aquatic vegetation are the main characteristics that explain the variation among different species. In contrast, water permanence is second in importance. Water temperature, pH and the type of larval habitat are less important in explaining the clustering of species. PMID:21739026

Stein, Marina; Ludueña-Almeida, Francisco; Willener, Juana Alicia; Almirón, Walter Ricardo

2011-06-01

335

Strong Predictability Of Spatially Distributed Physical Habitat Preferences For O. Mykiss Spawning Across Three Spatial Scales  

NASA Astrophysics Data System (ADS)

Currently accepted perception assumes Oncorhynchus mykiss prefer different ranges of similar physical habitat elements for spawning than Chinook salmon (Oncorhynchus tshawytscha), taking into account their difference in size. While there is increasing research interest regarding O. mykiss habitat use and migratory behavior, research conducted to date distinguishing the physical habitat conditions utilized for O. mykiss spawning has not provided quantified understanding of their spawning habitat preferences. The purpose of this study was to use electivity indices and other measures to assess the physical habitat characteristics preferred for O. mykiss spawning in terms of both 1-m scale microhabitat attributes, and landforms at different spatial scales from 0.1-100 times channel width. The testbed for this study was the 37.5-km regulated gravel-cobble Lower Yuba River (LYR). Using spatially distributed 2D hydrodynamic model results, substrate mapping, and a census of O. mykiss redds from two years of observation, micro- and meso-scale representations of physical habitat were tested for their ability to predict spawning habitat preference and avoidance. Overall there was strong stratification of O. mykiss redd occurrence for all representation types of physical habitat. A strong preference of hydraulic conditions was shown for mean water column velocities of 1.18-2.25 ft/s, and water depths of 1.25-2.76 ft. There was a marked preference for the two most upstream alluvial reaches of the LYR (out of 8 total reaches), accounting for 92% of all redds observed. The preferred morphological units (MUs) for O. mykiss spawning were more variable than for Chinook salmon and changed with increasing discharge, demonstrating that O. mykiss shift spawning to different MUs in order to utilize their preferred hydraulic conditions. The substrate range preferred for O. mykiss spawning was within 32-90 mm. Overall, O. mykiss spawning behavior was highly predictable and required a holistic blend of hydraulic and geomorphic representations to explain.

Kammel, L.; Pasternack, G. B.; Wyrick, J. R.; Massa, D.; Bratovich, P.; Johnson, T.

2012-12-01

336

Evaluating the consequences of habitat fragmentation: a case study in the common forest herb Trillium camschatcense  

Microsoft Academic Search

The effects of habitat fragmentation on remnant plant populations have rarely been studied extensively using a single species. We have attempted to quantify the effects of forest fragmentation (primarily that of population size) on populations of Trillium camschatcense, a representative spring herb in the Tokachi plain of Hokkaido, Japan. In this region, intensive agricultural development over the past 100 years has

Hiroshi Tomimatsu; Masashi Ohara

2006-01-01

337

Evaluating the Effect of Green Infrastructure Stormwater Best Management Practices on New England Stream Habitat  

EPA Science Inventory

The U.S. EPA is evaluating the effectiveness of green infrastructure (GI) stormwater best management practices (BMPs) on stream habitat at the small watershed (< HUC12) scale in New England. Predictive models for thermal regime and substrate characteristics (substrate size, % em...

338

Use of riverine through reef habitat systems by dog snapper ( Lutjanus jocu ) in eastern Brazil  

NASA Astrophysics Data System (ADS)

The early life history of Western Atlantic snappers from the Southern hemisphere is largely unknown. Habitat use of different life stages (i.e. size categories) of the dog snapper ( Lutjanus jocu) was examined across the largest South Atlantic reef-estuarine complex (Abrolhos Shelf, Brazil, 16-19° S). Visual surveys were conducted in different habitats across the shelf (estuary, inner-shelf reefs and mid-shelf reefs). Lutjanus jocu showed higher densities on inner-shelf habitats, with a clear increase in fish size across the shelf. Individuals <7 cm were associated with both the estuary (mangrove and rocky habitats) and inner-shelf reefs (particularly shallow fore-reefs and tide pools). Individuals ranging 10-30 cm were broadly distributed, but consistently more abundant on inner-shelf reefs. Individuals between 30 and 40 cm were more common on mid-shelf reefs, while individuals >40 cm were recorded only on mid-shelf reefs. Literature data indicate that individuals ranging 70-80 cm are common on deep offshore reefs. This pattern suggests that the dog snapper performs ontogenetic cross-shelf migrations. Protecting portions of the different habitats used by the dog snapper during its post-settlement life cycle is highlighted as an important conservation and management measure.

Moura, Rodrigo L.; Francini-Filho, Ronaldo B.; Chaves, Eduardo M.; Minte-Vera, Carolina V.; Lindeman, Kenyon C.

2011-11-01

339

Patterns of space and habitat use by northern bobwhites in South Florida, USA  

USGS Publications Warehouse

The manner by which animals use space and select resources can have important management consequences. We studied patterns of habitat selection by northern bobwhites (Colinus virginianus) on Babcock-Webb Wildlife Management Area, Charlotte County, Florida and evaluated factors influencing the sizes of their home ranges. A total of 1,245 radio-tagged bobwhites were monitored for 19,467 radio days during 2002-2007. The mean (?? 1 SE) annual home range size, estimated using the Kernel density method, was 88. 43 (?? 6. 16) ha and did not differ between genders. Winter home ranges of bobwhites (69. 27 ?? 4. 92 ha) were generally larger than summer home ranges (53. 90 ?? 4. 93 ha). Annual and winter home ranges were smaller for bobwhites whose ranges contained food plots compared to those that did not; however, the presence of food plots did not influence summer home ranges. We used distance-based methods to investigate habitat selection by bobwhites at two scales: selection of home ranges within the study site (second-order selection) and selection of habitats within home ranges (third-order selection). Across both scales, bobwhites generally preferred food plots and dry prairie habitat and avoided wet prairies and roads. This pattern was generally consistent between genders and across years. Our data indicate that management practices aimed at increasing and maintaining a matrix of food plots and dry prairie habitat would provide the most favorable environment for bobwhites. ?? 2010 Springer-Verlag.

Singh, A.; Hines, T. C.; Hostetler, J. A.; Percival, H. F.; Oli, M. K.

2011-01-01

340

Home range and habitat use by Great Horned Owls (Bubo virginianus) in Southern California  

USGS Publications Warehouse

Great Horned Owls (Bubo virginianus) are a common, widespread species that can be found in a variety of habitats across most of North America, but little is known about their space and habitat requirements. Using radiotelemetry, location data were collected on nine male and five female Great Horned Owls to determine home range and habitat use in southern California. Owls were tracked between January 1997 and September 1998 for periods ranging from 5-17 mo. Seven owls were also followed during 13 all-night observation periods. The mean 95% adaptive kernel home-range size for females was 180 ha (range = 88-282, SE = 36) and that for males was 425 ha (range = 147-1115 ha, SE = 105). Core areas estimated by the 50% adaptive kernel averaged 27 ha (range = 7-44, SE = 7) for females and 61 ha (range = 15-187, SE = 18) for males. Owls were located in areas with varying degrees of human disturbance ranging from almost entirely urban to native oak (Quercus agrifolia) woodland. Oak/sycamore (Quercus agrifolia/Platanus racemosa) woodland and ruderal grassland (Bromus spp., Avena spp., and various other non-native invasives), were used more often than expected based on availability, but we found no correlation between home-range size and any single habitat type or habitat groups. ?? 2005 The Raptor Research Foundation, Inc.

Bennett, J. R.; Bloom, P. H.

2005-01-01

341

Evaluation of two methods of estimating larval habitat productivity in western Kenya highlands  

PubMed Central

Background Malaria vector intervention and control programs require reliable and accurate information about vector abundance and their seasonal distribution. The availability of reliable information on the spatial and temporal productivity of larval vector habitats can improve targeting of larval control interventions and our understanding of local malaria transmission and epidemics. The main objective of this study was to evaluate two methods of estimating larval habitat productivity in the western Kenyan highlands, the aerial sampler and the emergence trap. Methods The study was conducted during the dry and rainy seasons in 2008, 2009 and 2010. Aerial samplers and emergence traps were set up for sixty days in each season in three habitat types: drainage ditches, natural swamps, and abandoned goldmines. Aerial samplers and emergence traps were set up in eleven places in each habitat type. The success of each in estimating habitat productivity was assessed according to method, habitat type, and season. The effect of other factors including algae cover, grass cover, habitat depth and width, and habitat water volume on species productivity was analysed using stepwise logistic regression Results Habitat productivity estimates obtained by the two sampling methods differed significantly for all species except for An. implexus. For for An. gambiae s.l. and An. funestus, aerial samplers performed better, 21.5 and 14.6 folds, than emergence trap respectively, while the emergence trap was shown to be more efficient for culicine species. Seasonality had a significant influence on the productivity of all species monitored. Dry season was most productive season. Overall, drainage ditches had significantly higher productivity in all seasons compared to other habitat types. Algae cover, debris, chlorophyll-a, and habitat depth and size had significant influence with respect to species. Conclusion These findings suggest that the aerial sampler is the better of the two methods for estimating the productivity of An. gambiae s.l. and An. funestus in the western Kenya highlands and possibly other malaria endemic parts of Africa. This method has proven to be a useful tool for monitoring malaria vector populations and for control program design, and provides useful means for determining the most suitable sites for targeted interventions.

2011-01-01

342

SALMON SPAWNING & REARING HABITAT IN OREGON  

EPA Science Inventory

Spawning & rearing, rearing only, and essential habitat identified by Oregon Dept. Fish & Wildlife for chum, coho, fall chinook, and spring chinook salmon in Oregon. Each of the species workspaces contains coverages specific to individual USGS hydrologic cataloging unit; each co...

343

The Habitat for Lactoris fernandeziana (Lactoridaceae)  

NSDL National Science Digital Library

View of ""Tres Picos"" (Three Peaks) from Villagra on Robinson Crusoe Island, which is in the Juan Fernandez archipelago off the coast of Chile. The closer vegetation represents the habitat for Lactoris fernandeziana (Lactoridaceae).

Gregory J. Anderson (University of Connecticut;Department of Ecology and Evolutionary Biology ADR;POSTAL)

2004-03-09

344

Environmental Habitat Conditions Associated with Freshwater Dreissenids.  

National Technical Information Service (NTIS)

The continued spread of two invasive dreissenid bivalve species, zebra (Dreissena polymorpha) and quagga (D. bugensis) mussels, into the southwestern and western United States indicates the need for improving understanding of habitat requirements and cons...

B. S. Payne M. D. Farr

2010-01-01

345

Lunar and Planetary Bases, Habitats, and Colonies.  

National Technical Information Service (NTIS)

This special bibliography includes the design and construction of lunar and Mars bases, habitats, and settlements; construction materials and equipment; life support systems; base operations and logistics; thermal management and power systems; and robotic...

2004-01-01

346

Subsurface Microbial Habitats on Mars (Abstract Only).  

National Technical Information Service (NTIS)

We developed scenarios for shallow and deep subsurface cryptic niches for microbial life on Mars. Such habitats could have considerably prolonged the persistence of life on Mars as surface conditions became increasingly inhospitable. The scenarios rely on...

P. J. Boston C. P. Mckay

1991-01-01

347

Geography Action! Habitats: Home Sweet Home  

NSDL National Science Digital Library

National Geographic's Geography Action! is an "annual conservation and awareness program designed to educate and excite people about our natural, cultural, and historic treasures." This year the theme is Habitats: Home Sweet Home. Just as there are an amazing variety of habitats on the planet, so does this Web site have an amazing variety of features. In addition to habitat-specific lesson plans (ranging from grades K-12), visitors will find fantastic collections of National Geographic photos; interesting Web links; and several interactive multimedia adventures, such as piloting a mini-sub through a virtual kelp forest or taking an animated trek through the Arctic. The site also provides numerous ideas for exploring and protecting your own habitat.

348

EPA'S BENTHIC HABITAT DATA FOR YAQUINA ESTUARY  

EPA Science Inventory

Scientists at EPA's National Health and Environmental Effects Research Laboratory, Western Ecology Division (WED) have been studying seafloor (benthic) habitats in Yaquina estuary for several years. Those studies were conducted as parts of several research projects, including: e...

349

map showing predicted habitat potentional for tortoise  

USGS Multimedia Gallery

This map shows the spatial representation of the predicted habitat potential index values for desert tortoise in the Mojave and parts of the Sonoran Deserts of California, Nevada, Utah, and Arizona. Map: USGS. ...

2009-05-21

350

HABITAT FRAGMENTATION CUMULATIVE IMPACT SCREENING ANALYSIS  

EPA Science Inventory

Region 6 EPA uses a GIS screening system to evaluate specific areas and construction projects within our five states. The methodology evaluates disruptions to landscape through evaluation of wildlife habitat quantity and quality, endangered species, surface and groundwater vulne...

351

Online Courses: WCS: Habitat Ecology for Educators  

NSDL National Science Digital Library

Living things have evolved over millions of years to exist in particular environments. We call those environments habitats, and we say that species are adapted to them. The interrelationships among plants, animals, climate, and seasons of a particular hab

1900-01-01

352

Space habitats. [prognosis for space colonization  

NASA Technical Reports Server (NTRS)

Differences between space industrialization and space colonization are outlined along with the physiological, psychological, and esthetic needs of the inhabitants of a space habitat. The detrimental effects of zero gravity on human physiology are reviewed, and the necessity of providing artificial gravity, an acceptable atmosphere, and comfortable relative humidity and temperature in a space habitat is discussed. Consideration is also given to social organization and governance, supply of food and water, and design criteria for space colonies.

Johnson, R. D.

1978-01-01

353

Non-indigenous species in Mediterranean fish assemblages: Contrasting feeding guilds of Posidonia oceanica meadows and sandy habitats  

NASA Astrophysics Data System (ADS)

Quantitative sampling in combination with classification of fish species into six major feeding guilds revealed the position and contribution of non-indigenous species (NIS) in the food web of Posidonia oceanica and sandy habitats in an area of the eastern Mediterranean. In P. oceanica beds and on sandy bottoms 10 and five species, respectively, were non-indigenous fish of Indo-Pacific origin. The proportional contribution of NIS individuals on P. oceanica beds was lower than that of sandy bottoms (12.7 vs. 20.4%) a pattern that also followed for biomass (13.6 vs. 23.4%), indicating that low diverse systems may be more liable to introductions than species-rich communities. The two habitats had similar fish feeding guilds, but the biomass contribution from NIS varied within each guild, indicating different degrees of impact on the available resources. This study showed that only few non-indigenous fish species contributed to the differences in biomass between habitats. No support could be found in postulating that taxonomic affiliation could predict invasion success. Size was considered highly important due to habitat shift of species with increased size. Two of the aspects considered in this study, the chance of establishing vs. the chance of being very dominant will depend upon competitive abilities strongly coupled to size and grounds for habitat shift. However, success of establishment will also depend on appropriate food resources in the recipient community as well as competitive abilities and level of competition in the food web within habitats.

Kalogirou, S.; Wennhage, H.; Pihl, L.

2012-01-01

354

NEKTON-HABITAT ASSOCIATIONS IN YAQUINA BAY, OREGON  

EPA Science Inventory

Habitat-based ecological risk assessments rely, in part, on estimates of the ecological value of the habitats at risk. To estimate estuarine habitat values with respect to the nekton (small fish, crabs and other invertebrates), we determined nekton-habitat associations in four i...

355

Population status, demography and habitat preferences of the threatened lipstick palm Cyrtostachys renda Blume in Kerumutan Reserve, Sumatra  

Microsoft Academic Search

Population status and demography of a population of the threatened lipstick palm Cyrtostachys renda in a peat swamp ecosystem of Kerumutan Reserve, Sumatra (one of the largest remaining populations) was documented at 16 different sites, covering a wide range of forest and habitat types, vegetation associations, and population sizes. Population sizes were dominated by suckers comprising 89% of the total

Didik Widyatmoko; Mark A. Burgman; Edi Guhardja; Johanis P. Mogea; Eko B. Walujo; Dede Setiadi

2005-01-01

356

Assessing habitat selection when availability changes  

USGS Publications Warehouse

We present a method of comparing data on habitat use and availability that allows availability to differ among observations. This method is applicable when habitats change over time and when animals are unable to move throughout a predetermined study area between observations. We used maximum-likelihood techniques to derive an index that estimates the probability that each habitat type would be used if all were equally available. We also demonstrate how these indices can be used to compare relative use of available habitats, assign them ranks, and assess statistical differences between pairs of indices. The set of these indices for all habitats can be compared between groups of animals that represent different seasons, sex or age classes, or experimental treatments. This method allows quantitative comparisons among types and is not affected by arbitrary decisions about which habitats to include in the study. We provide an example by comparing the availability of four categories of sea ice concentration to their use by adult female polar bears, whose movements were monitored by satellite radio tracking in the Bering and Chukchi Seas during 1990. Use of ice categories by bears was nonrandom, and the pattern of use differed between spring and late summer seasons.

Arthur, S.; Garner, G.; et al

1996-01-01

357

Serving Sizes  

NSDL National Science Digital Library

In this nutrition and estimation activity (page 12 of PDF), learners estimate serving sizes of different foods and compare their estimates to serving size information provided on nutrition food labels. A Quick Hand Measures guide helps learners visualize serving sizes of different foods using their hand (i.e. a closed fist = serving size of a piece of fruit). This activity also introduces learners to solid and liquid measures. This guide includes background information, setup and management tips, extensions, reliable resource links and handouts.

Moreno, Nancy P.; Clayton, Sonia R.; Cutler, Paula H.; Young, Martha S.; Tharp, Barbara Z.

2009-01-01

358

Lake trout spawning habitat in the Great Lakes u a review of current knowledge  

USGS Publications Warehouse

We review existing information on lake trout spawning habitat, which might indicate whether habitat is now a limiting factor in lake trout reproductive success. Lake trout spawning habitat quality is defined by the presence or absence of olfactory cues for homing, reef location with respect to the shoreline, water depth, proximity to nursery areas, reef size, contour, substrate size and shape, depth of interstitial spaces, water temperature at spawning time, water quality in interstitial spaces, and the presence of egg and fry predators. Data on factors which attracted native spawners to spawning reefs are lacking, due to the absence of historic data on egg deposition. No direct evidence of egg deposition has been collected from sites deeper than 18 m. Interstitial space and, therefore, substrate size and shape, appear to be critical for both site selection by adults and protection of eggs and fry. Water quality is clearly important for egg incubation, but the critical parameters which define water quality have not yet been well determined in the field. Exposure to wave energy, dictated in part by reef location, may maintain high water quality but may also damage or dislodge eggs. The importance of olfactory cues, water temperature, and proximity to nursery habitat to spawning trout is unclear. Limited data suggest that egg and fry predators, particularly exotic species, may critically affect fry production and survival. Although availability of physical spawning habitat is probably not limiting lake trout reproduction, changes in water quality and species composition may negatively affect early life stages. This review of habitat factors that affect early life stages of lake trout suggests several priorities for research and management.

Marsden, J. Ellen; Casselman, John M.; Edsall, Thomas A.; Elliott, Robert F.; Fitzsimons, John D.; Horns, William H.; Manny, Bruce A.; McAughey, Scott C.; Sly, Peter G.; Swanson, Bruce L.

1995-01-01

359

Habitat comparisons and productivity in nesting common terns on the mid-Atlantic coast  

USGS Publications Warehouse

Nesting Common Terns (Sterna hirundo) were studied at a number of barrier beaches and small islands of tidal salt marsh in New Jersey and the Eastern Shore of Maryland-Virginina from 1980 through 1982. Data were collected on clutch sizes, nest spacing, and nesting success. The principal null hypothesis tested was that no difference in reproductive success exists between beach and marsh habitats. Nests were monitored from egg-laying in mid-May until mid-July when young fledged. Clutch sizes varied among colonies and across years but no systematic effect of year, habitat, or colony size on mean clutch size per colony was detected. Analyses of nest productivity (estimated using both the Mayfield method and using a colony average) failed to reveal significant effects of habitat or colony size but showed a stronger year effect. Storm tide flooding and egg chick disappearance (presumably predation by Herring Gulls Larus argentatus and Laughing Gulls L. atricilla nesting nearby) accounted for most nest failures. Losses due to both these mortality factors were unpredictable from year to year. Nest spacing in salt marsh colonies was much closer than it was on barrier beaches. In mixed-species colonies with Black Skimmers (Rynchops niger), distances between tern and skimmer nests were also much smaller in marsh colonies than they were on beaches. The limited amount of wrack (windrows of dead, matted vegetation) preferred by marsh-nesting terns probably explains these spacing differences. Several lines of evidence suggest that terns prefer beaches to marshes for nesting, however, the uncertainty of predation and flooding may often obscure any intrinsic differences in habitat quality. Long-term field studies are essential for testing hypotheses related to differential fitness of individuals among habitats.

Erwin, R.M.; Smith, D.C.

1985-01-01

360

Breeding canvasbacks: a test of a habitat model  

USGS Publications Warehouse

Schroeder (1984) proposed a habitat suitability model for breeding canvasbacks (Aythya valisineria) based on the size, water regime, and emergent vegetation of wetlands. We evaluated the model with data from surveys of canvasbacks on 2265 wetlands in North Dakota, South Dakota, and Minnesota. The model proved inadequate as a predictor of canvasback pair density; the correlation between values produced by the model and canvasback pair densities was r = 0.0023 (P = 0.911). There were, however, suggestions of (1) higher canvasback density and frequency of occurrence on wetlands with more open interiors, and (2) a relation between canvasback density and wetland size that varied according to wetland permanence. We recommend that the model be improved by testing these relations, and possibly by incorporating determinants of water quality or pondweed (Potamogeton spp.) occurrence.

Johnson, D. H.; Hammond, M. C.; McDonald, T. L.; Nustad, C. L.

1989-01-01

361

Fine scale movements and habitat use of black brant during the flightless Wing Molt in Arctic Alaska  

USGS Publications Warehouse

Thousands of Black Brant (Branta bernicla nigricans) migrate annually to the Teshekpuk Lake Special Area (TLSA), Alaska, to undergo the flightless wing molt on tundra lakes and wetlands. GPS transmitters were attached to Brant over two summers (2007â€"2008) to examine patterns of movement and habitat use of molting Brant, including variation by habitat type, year and body mass. Molting Brant were located an average of 31 ±1 m (SE) from shore and this distance did not vary across any of the explanatory variables. Brant moved an average of 123 ±3 m hr -1 while flightless. Movement rates varied by year, averaging 22 ±12 m hr -1 faster in 2008, and across habitat types, averaging 22 ±13 m hr -1 faster in inland versus coastal and estuarine habitats. Two kernel home ranges were estimated: entire home range, which encompassed the complete 95% probability contour, and shoreline home range, which included only shoreline areas used by molting Brant. Entire home range (x bar = 15.1 ±2.2 km 2) was negatively correlated with body mass, suggesting that heavier individuals have more body reserves to contribute to feather growth and thereby require less food and smaller home ranges. Conversely, shoreline home range (x bar = 4.3 ±0.6 km 2) did not vary by body mass, but rather by habitat type, being larger in estuarine habitats. The complex shorelines and numerous deltaic islands of estuarine habitats offer more shoreline per area than either coastal or inland habitats. Brant appear to have limited ability to adjust their home range size or forage further from shore in response to variable food resources across years or habitats, instead altering their movement rate. Given this apparent lack of behavioral flexibility, Brant may be sensitive to development-related disturbances or habitat losses at molt sites in the TLSA.

Lewis, Tyler L.; Flint, Paul L.; Derksen, Dirk V.; Schmutz, Joel A.

2011-01-01

362

Developing landscape-scaled habitat selection functions for forest wildlife from Landsat data: Judging black bear habitat quality in Louisiana  

Microsoft Academic Search

Understanding habitat needs of animal populations is critical for their effective management. In recent years, technological advances have increased the range of methods available to examine habitat selection patterns. However, available habitat data are often either limited to small geographic areas or are of coarse resolution, resulting in a gap in data to model habitat selection at landscape scales. I

Robert Owen Wagner

2003-01-01

363

Size Matters  

ERIC Educational Resources Information Center

This article describes the immense size of Unity Junior High School in Cicero, Illinois and the opinions of various people regarding its size. The school has more than 2,700 students, seventeen acres, eighty-eight faculty lounges, and ninety-six security cameras. Administrators hope the school--"Cicero's crown jewel," as the school district's Web…

Gehring, John

2004-01-01

364

Size effect  

Microsoft Academic Search

This paper surveys the available results on the size effect on the nominal strength of structures — a fundamental problem of considerable importance to concrete structures, geotechnical structures, geomechanics, arctic ice engineering, composite materials, etc., with applications ranging from structural engineering to the design of ships and aircraft. The history of the ideas on the size effect is briefly outlined

Zden?k P. Bažant

2000-01-01

365

Habitat Suitability Index Models: Black-Shouldered Kite  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a model for evaluating black-shouldered kite habitat quality. The model is scaled to produce an index between 0 (unsuitable habitat) to 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application are provided.

Faanes, Craig A.; Howard, Rebecca J.

1987-01-01

366

Habitat Suitability Index Models: Northern Pintail (Gulf Coast Wintering)  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a model for evaluating wintering habitat quality for northern pintail (Anas acuta) along the Gulf of Mexico coast. The model is scaled to produce an index between unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are provided.

Howard, Rebecca J.; Kantrud, Harold A.

1986-01-01

367

Habitat Suitability Index Models: Black Bear, Upper Great Lakes Region  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the black bear (Ursus americanus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Rogers, Lynn L.; Allen, Arthur W.

1987-01-01

368

Habitat Suitability Index Models: Moose, Lake Superior Region  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the moose (Alces alces). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Allen, Arthur W.; Jordan, Peter A.; Terrell, James W.

1987-01-01

369

Habitat Suitability Index Models: Diamondback Terrapin (Nesting) - Atlantic Coast  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the diamondback terrapin (Malaclemys terrapin). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Palmer, William M.; Cordes, Carroll L.

1988-01-01

370

Habitat Suitability Index Models: Bald Eagle (Breeding Season)  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bald eagle (Haliaeetus leucocephalus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Peterson, Allen

1986-01-01

371

Using Satellite Imagery to Assess Large-Scale Habitat Characteristics of Adirondack Park, New York, USA  

NASA Astrophysics Data System (ADS)

Satellite imagery is a useful tool for large-scale habitat analysis; however, its limitations need to be tested. We tested these limitations by varying the methods of a habitat evaluation for white-tailed deer ( Odocoileus virginianus) in the Adirondack Park, New York, USA, utilizing harvest data to create and validate the assessment models. We used two classified images, one with a large minimum mapping unit but high accuracy and one with no minimum mapping unit but slightly lower accuracy, to test the sensitivity of the evaluation to these differences. We tested the utility of two methods of assessment, habitat suitability index modeling, and pattern recognition modeling. We varied the scale at which the models were applied by using five separate sizes of analysis windows. Results showed that the presence of a large minimum mapping unit eliminates important details of the habitat. Window size is relatively unimportant if the data are averaged to a large resolution (i.e., township), but if the data are used at the smaller resolution, then the window size is an important consideration. In the Adirondacks, the proportion of hardwood and softwood in an area is most important to the spatial dynamics of deer populations. The low occurrence of open area in all parts of the park either limits the effect of this cover type on the population or limits our ability to detect the effect. The arrangement and interspersion of cover types were not significant to deer populations.

McClain, Bobbi J.; Porter, William F.

2000-11-01

372

Early colonization of stone by freshwater lichens of restored habitats: a case study in northern Italy.  

PubMed

This study evaluated the effectiveness and life-strategies of freshwater lichens in colonizing newly constructed stone structures in low-elevation streams in a small nature reserve in northern Italy. Species richness, size of thalli, morphological and ontogenetic traits of the species were related to the age of restored habitats. Lichen colonization was surprisingly rapid, indicating the high potential of these organisms in colonizing restored habitats. However, the species pool found in the restored habitats was different than that found in natural sites in the same study area. The age of newly constructed habitats influenced both species richness and thallus size of the two most frequent Verrucaria species. Verrucaria aquatilis was a rapid colonizer invading the substrate by several small-sized and thin thalli which soon supported a large number of small perithecia whose development began in the earlier phase of thallus formation. V. elaeomelaena, on the contrary, developed according to a different strategy, establishing a thick thallus on which relatively large perithecia were formed much later than in V. aquatilis. As these taxa are important photoautotrophic components of freshwater ecosystems more ecological knowledge is needed to evaluate the effectiveness of different measures of river restoration on lichen communities. The main practical implication of our study is related to the value of small stone structures, such as riffles and ramps, for enhancing the establishment of pioneer freshwater lichens to rapidly colonize newly available substrata. PMID:19589560

Nascimbene, Juri; Thüs, Holger; Marini, Lorenzo; Nimis, Pier Luigi

2009-09-01

373

Habitat assessment, Missouri River at Hermann, Missouri  

USGS Publications Warehouse

This report documents methods and results of aquatic habitat assessment in the Missouri River near Hermann, Missouri. The assessment is intended to improve understanding of spatial and temporal variability of aquatic habitat, including habitats thought to be critical for the endangered pallid sturgeon (Scaphirhynchus albus). Physical aquatic habitat - depth, velocity, and substrate - was assessed around 9 wing dikes and adjacent to the U.S. Route 19 bridge, at discharges varying from 44,000 cubic feet per second (cfs) to 146, 000 cfs during August 2000-May, 2001. For the river as a whole, velocities are bi-modally distributed with distinct peaks relating to navigation channel and wing-dike environments. Velocities predictably showed an increasing trend with increasing discharge. Substrate within wing dikes was dominated by mud at low discharges, whereas the navigation channel had patches of transporting sand, rippled sand, and coarse sand. Discharges that overtopped the wing dikes (about 93,000 cfs, March 2001) were associated with increases of patchy sand, rippled sand, and coarse sand within the wing dikes. When flows were substantially over the wing dikes (146,000 cfs, May 2001) substrates within most wing dikes showed substantial reorganization and coarsening. The habitat assessment provides a geospatial database that can be used to query wing dikes for distributions of depth, velocity, and substrate for comparison with fish samples collected by US Fish and Wildlife Service biologists (Grady and others, 2001). In addition, the assessment documented spatial and temporal variation in habitat within the Hermann reach and over a range of discharges. Measurable geomorphic change--alteration of substrate conditions plus substantial erosion and deposition--was associated with flows equaled or exceeded 12-40% of the time (40-140 days per year). Documented geomorphic change associated with high-frequency flows underscores the natural temporal variability of physical habitat in the Lower Missouri River.

Jacobson, Robert B.; Laustrup, Mark S.; Reuter, Joanna M.

2002-01-01

374

Effects of tide cycles on habitat selection and habitat partitioning by migrating shorebirds  

USGS Publications Warehouse

We studied assemblages of feeding shorebirds in three intertidal habitats on the coast of New Jersey during August to document how species segregates patially both among and within habitats and to determine the effects of tidal cycles on these patterns. The habitats were a sandy beach facing the ocean proper (outer beach), a sandy beach on the mainland side of a barrier island (inner beach), and a small mudflat adjacent to a Spartina alternifiora salt marsh. We were able to identify several microhabitats on the outer beach and mudflat. Most speciesfe d in more than one habitat, but only two, Charadrius semipalmatus and Calidris canutus, used all three habitats regularly. Within habitats, most species exhibited strong preferences for the wettest areas, but we found differences among species in degrees of preference. The least amount of partitioning occurred on the inner beach, where birds crowded into a small zone near the water's edge and had frequent agonistic encounters suggesting intense competition. Shorebird feeding activity was partly a function of tide time: each habitat had a characteristic temporal pattern of use by shorebirds related to tide time rather than diel time; within habitats, we found species-characteristic feeding activity rhythms that were also a function of tide time. Feeding by most species peaked during the first 2 hours after low tide on the outer beach and mudflat. The results are discussed in terms of feeding strategies and interspecific competition.

Burger, J.; Howe, M.A.; Hahn, D.C.; Chase, J.

1977-01-01

375

Identifying Fish Habitats: the use of spatially explicit habitat modeling and prediction in marine research  

Microsoft Academic Search

New methods of optimally identifying and predicting marine habitat occurrence are needed to help best address management issues such as marine reserve designation, fisheries stock assessment and aquaculture planning across large areas. A combination of video sampling, acoustic remote sensing and learning-based classification methods are proposed as a means of optimally identifying marine habitats. More commonly used in the identification

Katrina Baxter; Mark Shortis

376

Assessing critical habitat: Evaluating the relative contribution of habitats to population  

EPA Science Inventory

A principal challenge of species conservation is to identify the specific habitats that are essential for long-term persistence or recovery of imperiled species. However, many approaches to identifying important habitats do not provide direct insight into the contribution of hab...

377

Size Wheel  

NSDL National Science Digital Library

In this fun sticker activity, learners will create a size wheel with images of objects of different size, from macroscopic scale (like an ant) to nanoscale (like DNA). Learners will be able to understand the difference in sizes and also learn about how small objects look when examined with special imaging technology such as a Scanning Electron Microscope. The activity includes images of: ant, dust mite, hair, virus, chromosome, spider web, penny, red blood cell, DNA, optic fiber, pollen grain, microchip, flagellum, plant cell, and silk threads.

Science, Lawrence H.

2007-01-01

378

Spatial distribution and habitat characterisation of Anopheles larvae along the Kenyan coast  

PubMed Central

Background & objectives A study was conducted to characterise larval habitats and to determine spatial heterogeneity of the Anopheles mosquito larvae. The study was conducted from May to June 1999 in nine villages along the Kenyan coast. Methods Aquatic habitats were sampled by use of standard dipping technique. The habitats were characterised based on size, pH, distance to the nearest house, coverage of canopy, surface debris, algae and emergent plants, turbidity, substrate, and habitat type. Results A total of 110 aquatic habitats like stream pools (n = 10); puddles (n = 65); tire tracks (n = 5); ponds (n = 5) and swamps (n = 25) were sampled in nine villages located in three districts of the Kenyan coast. A total of 7,263 Anopheles mosquito larvae were collected, 63.9% were early instars and 36.1% were late instars. Morphological identification of the III and IV instar larvae by use of microscopy yielded 90.66% (n = 2,377) Anopheles gambiae Complex, 0.88% (n = 23) An. funestus, An. coustani 7.63% (n = 200), An. rivulorum 0.42% (n = 11), An. pharoensis 0.19% (n = 5), An. swahilicus 0.08% (n = 2), An. wilsoni 0.04% (n = 1) and 0.11% (n = 3) were unidentified. A subset of the An. gambiae Complex larvae identified morphologically, was further analysed using rDNA-PCR technique resulting in 68.22% (n = 1,290) An. gambiae s.s., 7.93% (n = 150) An. arabiensis and 23.85% (n = 451) An. merus. Multiple logistic regression model showed that emergent plants (p = 0.019), and floating debris (p = 0.038) were the best predictors of An. gambiae larval abundance in these habitats. Interpretation & conclusion Habitat type, floating debris and emergent plants were found to be the key factors determining the presence of Anopheles larvae in the habitats. For effective larval control, the type of habitat should be considered and most productive habitat type be given a priority in the mosquito abatement programme.

Mwangangi, Joseph M.; Mbogo, Charles M.; Muturi, Ephantus J.; Nzovu, Joseph G.; Githure, John I.; Yan, Guiyun; Minakawa, Noboru; Novak, Robert; Beier, John C.

2009-01-01

379

Spatial and temporal shifts in suitable habitat of juvenile southern flounder (Paralichthys lethostigma)  

NASA Astrophysics Data System (ADS)

Factors influencing suitable habitats of juvenile southern flounder (Paralichthys lethostigma) within the Galveston Bay Complex (GBC), Texas, were assessed using generalized additive models (GAM). Fishery independent data collected with bag seines throughout the GBC from 1999 to 2009 were used to predict the probability of southern flounder occurrence. Binomial GAMs were used to assess presence/absence of southern flounder and models included temporal variables, benthic variables such as distance to habitats generated within a geographic information system, and physicochemical conditions of the water column. Separate models were generated for newly settled southern flounder, young-of-the-year (YOY) southern flounder observed in the summer, and YOY southern flounder observed in fall based on size and collection month. Factors affecting southern flounder occurrence changed seasonally, as did the corresponding shifts in the spatial distribution of suitable habitat. Temporal effects (year and month) were retained in all models. Physicochemical conditions (temperature, turbidity, and measures of environmental variability), and the presence of seagrass beds were influential for newly settled southern flounder. Distance to marine and/or freshwater sources were found to be important for YOY southern flounder in the summer and fall seasons. The abundance of brown shrimp was found to only influence the distribution of YOY southern flounder in the fall, when intermediate abundances of the potential prey item increased the occurrence of southern flounder. After model completion, the availability and spatial distribution of suitable habitat within the GBC was predicted using available environmental and spatial data for 2005. Spatial distributions of predicted suitable habitat stress the relative importance of West Bay during the newly settled stage and in the fall season, and Upper Bay during the summer and fall of the first year of life. These models demonstrate the potential dynamics of suitable habitats for juvenile southern flounder and provide insight into ontogenetic shifts in habitat preference during the first year of life.

Furey, Nathan B.; Rooker, Jay R.

2013-02-01

380

Models of Regional Habitat Quality and Connectivity for Pumas (Puma concolor) in the Southwestern United States  

PubMed Central

The impact of landscape changes on the quality and connectivity of habitats for multiple wildlife species is of global conservation concern. In the southwestern United States, pumas (Puma concolor) are a well distributed and wide-ranging large carnivore that are sensitive to loss of habitat and to the disruption of pathways that connect their populations. We used an expert-based approach to define and derive variables hypothesized to influence the quality, location, and permeability of habitat for pumas within an area encompassing the entire states of Arizona and New Mexico. Survey results indicated that the presence of woodland and forest cover types, rugged terrain, and canyon bottom and ridgeline topography were expected to be important predictors of both high quality habitat and heightened permeability. As road density, distance to water, or human population density increased, the quality and permeability of habitats were predicted to decline. Using these results, we identified 67 high quality patches across the study area, and applied concepts from electronic circuit theory to estimate regional patterns of connectivity among these patches. Maps of current flow among individual pairs of patches highlighted possible pinch points along two major interstate highways. Current flow summed across all pairs of patches highlighted areas important for keeping the entire network connected, regardless of patch size. Cumulative current flow was highest in Arizona north of the Colorado River and around Grand Canyon National Park, and in the Sky Islands region owing to the many small habitat patches present. Our outputs present a first approximation of habitat quality and connectivity for dispersing pumas in the southwestern United States. Map results can be used to help target finer-scaled analyses in support of planning efforts concerned with the maintenance of puma metapopulation structure, as well as the protection of landscape features that facilitate the dispersal process.

Dickson, Brett G.; Roemer, Gary W.; McRae, Brad H.; Rundall, Jill M.

2013-01-01

381

Predictions of adult Anopheles albimanus densities in villages based on distances to remotely sensed larval habitats  

NASA Technical Reports Server (NTRS)

Remote sensing is particularly helpful for assessing the location and extent of vegetation formations, such as herbaceous wetlands, that are difficult to examine on the ground. Marshes that are sparsely populated with emergent macrophytes and dense cyanobacterial mats have previously been identified as very productive Anopheles albimanus larval habitats. This type of habitat was detectable on a classified multispectral System Probatoire d'Observation de la Terre image of northern Belize as a mixture of two isoclasses. A similar spectral signature is characteristic for vegetation of river margins consisting of aquatic grasses and water hyacinth, which constitutes another productive larval habitat. Based on the distance between human settlements (sites) of various sizes and the nearest marsh/river exhibiting this particular class combination, we selected two groups of sites: those located closer than 500 m and those located more than 1,500 m from such habitats. Based on previous adult collections near larval habitats, we defined a landing rate of 0.5 mosquitoes/human/min from 6:30 PM to 8:00 PM as the threshold for high (> or = 0.5 mosquitoes/human/min) versus low (< 0.5 mosquitoes/human/min) densities of An. albimanus. Sites located less than 500 m from the habitat were predicted as having values higher than this threshold, while lower values were predicted for sites located greater than 1,500 m from the habitat. Predictions were verified by collections of mosquitoes landing on humans. The predictions were 100% accurate for sites in the > 1,500-m category and 89% accurate for sites in the < 500-m category.

Rejmankova, E.; Roberts, D. R.; Pawley, A.; Manguin, S.; Polanco, J.

1995-01-01

382

Modeling spatial and temporal variation of suitable nursery habitats for Atlantic sturgeon in the Chesapeake Bay  

NASA Astrophysics Data System (ADS)

For rare and endangered species, bioenergetics modeling can represent a valuable approach for understanding issues of habitat value and connectivity among potential habitats within nurseries in restoration programs. We used multivariable bioenergetics and survival models for Atlantic sturgeon to generate spatially explicit maps of potential production in the Chesapeake Bay. For the period 1993-2002, spatial and temporal patterns in water quality effects (temperature, dissolved oxygen [DO] and salinity) on potential production were evaluated. In addition, two forecasted scenarios were modeled: one implementing newly revised U.S. Environmental Protection Agency (EPA) DO-criteria for the Chesapeake Bay, and the other assuming a bay-wide increase of 1 °C due to an underlying trend in regional climate. Atlantic sturgeon's low (survival/growth) tolerance to temperatures >28 °C was a critical constraint during their first 1-2 summers of life. Hatched in freshwater (spring to mid-summer), young-of-the-year were predicted to occupy cooler (deeper) areas as temperature approached sub-lethal levels. While most thermal refuges were located down-estuary, a large fraction of potential refuges were unsuitable due to persistent hypoxia and/or salinity levels beyond the limited osmoregulatory capabilities of early juvenile Atlantic sturgeon. As a result, suitable summer habitats for juvenile Atlantic sturgeons in the Chesapeake Bay were predicted to be spatially restricted and variable between years, ranging from 0 to 35% of the modeled bay surface area. In critical (drought) years, almost no summer habitat was predicted to be available for juvenile Atlantic sturgeon. Value and size of nursery habitat was highly sensitive to climatic oscillations and anthropogenic interventions affecting freshwater inflow, water temperature and/or DO. Achieving EPA DO-criteria for the Chesapeake Bay was predicted to increase total suitable habitat by 13% for an average year, while increasing water temperature by just 1 °C bay-wide would reduce suitable habitat by 65%.

Niklitschek, Edwin J.; Secor, David H.

2005-07-01

383

Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts  

USGS Publications Warehouse

Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter "beaver") populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities. Few systematic studies have been conducted on the value of beaver-modified habitats for scrub-shrub birds, and these data are important for understanding habitat selection of scrub-shrub birds as well as for assessing regional habitat availability for these species. We conducted surveys in 37 beaver meadows in a 2,800-km2 study area in western Massachusetts during 2005 and 2006 to determine the extent to which these beaver-modified habitats are used by scrub-shrub birds, as well as the characteristics of beaver meadows most closely related to bird use. We modeled bird abundance in relation to microhabitat-, patch-, and landscape-context variables while adjusting for survey-specific covariates affecting detectability using N-mixture models. We found that scrub-shrub birds of regional conservation concern occupied these sites and that birds responded differently to microhabitat, patch, and landscape characteristics of beaver meadows. Generally, scrub-shrub birds increased in abundance along a gradient of increasing vegetation complexity, and three species were positively related to patch size. We conclude that these habitats can potentially play an important role in regional conservation of scrub-shrub birds and recommend that conservation priority be given to larger beaver meadows with diverse vegetation structure and composition. ?? 2009 by The American Ornithologists' Union. All rights reserved.

Chandler, R. B.; King, D. I.; Destefano, S.

2009-01-01

384

Models of regional habitat quality and connectivity for pumas (Puma concolor) in the southwestern United States.  

PubMed

The impact of landscape changes on the quality and connectivity of habitats for multiple wildlife species is of global conservation concern. In the southwestern United States, pumas (Puma concolor) are a well distributed and wide-ranging large carnivore that are sensitive to loss of habitat and to the disruption of pathways that connect their populations. We used an expert-based approach to define and derive variables hypothesized to influence the quality, location, and permeability of habitat for pumas within an area encompassing the entire states of Arizona and New Mexico. Survey results indicated that the presence of woodland and forest cover types, rugged terrain, and canyon bottom and ridgeline topography were expected to be important predictors of both high quality habitat and heightened permeability. As road density, distance to water, or human population density increased, the quality and permeability of habitats were predicted to decline. Using these results, we identified 67 high quality patches across the study area, and applied concepts from electronic circuit theory to estimate regional patterns of connectivity among these patches. Maps of current flow among individual pairs of patches highlighted possible pinch points along two major interstate highways. Current flow summed across all pairs of patches highlighted areas important for keeping the entire network connected, regardless of patch size. Cumulative current flow was highest in Arizona north of the Colorado River and around Grand Canyon National Park, and in the Sky Islands region owing to the many small habitat patches present. Our outputs present a first approximation of habitat quality and connectivity for dispersing pumas in the southwestern United States. Map results can be used to help target finer-scaled analyses in support of planning efforts concerned with the maintenance of puma metapopulation structure, as well as the protection of landscape features that facilitate the dispersal process. PMID:24367495

Dickson, Brett G; Roemer, Gary W; McRae, Brad H; Rundall, Jill M

2013-01-01

385

Microsatellite length variation in candidate genes correlates with habitat in the gilthead sea bream Sparus aurata.  

PubMed

The genetic basis and evolutionary implications of local adaptation in high gene flow marine organisms are still poorly understood. In several Mediterranean fish species, alternative migration patterns exist between individuals entering coastal lagoons that offer favourable conditions for growth and those staying in the sea where environmental conditions are less subject to rapid and stressful change. Whether these coexisting strategies are phenotypically plastic or include a role for local adaptation through differential survival needs to be determined. Here, we explore the genetic basis of alternate habitat use in western Mediterranean populations of the gilthead sea bream (Sparus aurata). Samples from lagoonal and open-sea habitats were typed for three candidate gene microsatellite loci, seven anonymous microsatellites and 44 amplified fragment length polymorphism markers to test for genotype-environment associations. While anonymous markers globally indicated high levels of gene flow across geographic locations and habitats, non-neutral differentiation patterns correlated with habitat type were found at two candidate microsatellite loci located in the promoter region of the growth hormone and prolactin genes. Further analysis of these two genes revealed that a mechanism based on habitat choice alone could not explain the distribution of genotype frequencies at a regional scale, thus implying a role for differential survival between habitats. We also found an association between allele size and habitat type, which, in the light of previous studies, suggests that polymorphisms in the proximal promoter region could influence gene expression by modulating transcription factor binding, thus providing a potential explanatory link between genotype and growth phenotype in nature. PMID:23061421

Chaoui, Lamya; Gagnaire, Pierre-Alexandre; Guinand, Bruno; Quignard, Jean-Pierre; Tsigenopoulos, Costas; Kara, M Hichem; Bonhomme, François

2012-11-01

386

Age-0 Lost River sucker and shortnose sucker nearshore habitat use in Upper Klamath Lake, Oregon: A patch occupancy approach  

USGS Publications Warehouse

We examined habitat use by age-0 Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris over six substrate classes and in vegetated and nonvegetated areas of Upper Klamath Lake, Oregon. We used a patch occupancy approach to model the effect of physical habitat and water quality conditions on habitat use. Our models accounted for potential inconsistencies in detection probability among sites and sampling occasions as a result of differences in fishing gear types and techniques, habitat characteristics, and age-0 fish size and abundance. Detection probability was greatest during mid- to late summer, when water temperatures were highest and age-0 suckers were the largest. The proportion of sites used by age-0 suckers was inversely related to depth (range = 0.4-3.0 m), particularly during late summer. Age-0 suckers were more likely to use habitats containing small substrate (64 mm) and habitats with vegetation than those without vegetation. Relatively narrow ranges in dissolved oxygen, temperature, and pH prevented us from detecting effects of these water quality features on age-0 sucker nearshore habitat use.

Burdick, S. M.; Hendrixson, H. A.; VanderKooi, S. P.

2008-01-01

387

Comparison of subyearling fall chinook salmon's use of riprap revetments and unaltered habitats in Lake Wallula of the Columbia river  

USGS Publications Warehouse

Subyearling fall chinook salmon's Oncorhynchus tshawytscha use of unaltered and riprap habitats in Lake Wallula of the Columbia River was determined with point abundance data collected by electrofishing in May 1994 and 1995. We documented the presence or absence of subyearlings at 277 sample sites and collected physical habitat information at each site. Based on logistic regression, we found that the probability of fish presence was greater in unaltered shoreline habitats than in riprap habitats. Substrate size was the most important factor in determining fish presence, with dominant substrates larger than 256 mm having the lowest probability of fish presence. Water velocity, also included in our model due to its biological importance, was not a significant factor affecting presence or absence (P = 0.1102). The correct prediction rate of fish presence or absence in our sample sites using cross validation was 67%. Our model showed that substrate was the most important factor determining subyearling habitat use, but the model did not include other habitat variables known to be important to subyearlings in more diverse systems. We suggest that resource managers consider alternative methods of bank stabilization that are compatible with the habitat requirements of the fish that use them.

Garland, R. D.; Tiffan, K. F.; Rondorf, D. W.; Clark, L. O.

2002-01-01

388

Variables influencing the presence of subyearling fall Chinook salmon in shoreline habitats of the Hanford Reach, Columbia River  

USGS Publications Warehouse

Little information currently exists on habitat use by subyearling fall Chinook salmon Oncorhynchus tshawytscha rearing in large, main-stem habitats. We collected habitat use information on subyearlings in the Hanford Reach of the Columbia River during May 1994 and April-May 1995 using point abundance electrofishing. We analyzed measures of physical habitat using logistic regression to predict fish presence and absence in shoreline habitats. The difference between water temperature at the point of sampling and in the main river channel was the most important variable for predicting the presence and absence of subyearlings. Mean water velocities of 45 cm/s or less and habitats with low lateral bank slopes were also associated with a greater likelihood of subyearling presence. Intermediate-sized gravel and cobble substrates were significant predictors of fish presence, but small (256-mm) substrates were not. Our rearing model was accurate at predicting fish presence and absence using jackknifing (80% correct) and classification of observations from an independent data set (76% correct). The habitat requirements of fall Chinook salmon in the Hanford Reach are similar to those reported for juvenile Chinook salmon in smaller systems but are met in functionally different ways in a large river.

Tiffan, K. F.; Clark, L. O.; Garland, R. D.; Rondorf, D. W.

2006-01-01

389

Habitat specialization through germination cueing: a comparative study of herbs from forests and open habitats  

PubMed Central

Background and Aims This study examined the adaptive association between seed germination ecology and specialization to either forest or open habitats across a range of evolutionary lineages of seed plants, in order to test the hypotheses that (1) species' specialization to open vs. shaded habitats is consistently accompanied by specialization in their regeneration niche; and (2) species are thereby adapted to utilize different windows of opportunity in time (season) and space (habitat). Methods Seed germination response to temperature, light and stratification was tested for 17 congeneric pairs, each consisting of one forest species and one open-habitat species. A factorial design was used with temperature levels and diurnal temperature variation (10 °C constant, 15–5 °C fluctuating, 20 °C constant, 25–15 °C fluctuating), and two light levels (light and darkness) and a cold stratification treatment. The congeneric species pair design took phylogenetic dependence into account. Key Results Species from open habitats germinated better at high temperatures, whereas forest species performed equally well at low and high temperatures. Forest species tended to germinate only after a period of cold stratification that could break dormancy, while species from open habitats generally germinated without cold stratification. The empirically derived germination strategies correspond quite well with establishment opportunities for forest and open-habitat plant species in nature. Conclusions Annual changes in temperature and light regime in temperate forest delimit windows of opportunity for germination and establishment. Germination strategies of forest plants are adaptations to utilize such narrow windows in time. Conversely, lack of fit between germination ecology and environment may explain why species of open habitats generally fail to establish in forests. Germination strategy should be considered an important mechanism for habitat specialization in temperate herbs to forest habitats. The findings strongly suggest that phases in the plant life cycle other than the established phase should be considered important in adaptive specialization.

ten Brink, Dirk-Jan; Hendriksma, Harmen Pieter; Bruun, Hans Henrik

2013-01-01

390

An index of reservoir habitat impairment  

USGS Publications Warehouse

Fish habitat impairment resulting from natural and anthropogenic watershed and in-lake processes has in many cases reduced the ability of reservoirs to sustain native fish assemblages and fisheries quality. Rehabilitation of impaired reservoirs is hindered by the lack of a method suitable for scoring impairment status. To address this limitation, an index of reservoir habitat impairment (IRHI) was developed by merging 14 metrics descriptive of common impairment sources, with each metric scored from 0 (no impairment) to 5 (high impairment) by fisheries scientists with local knowledge. With a plausible range of 5 to 25, distribution of the IRHI scores ranged from 5 to 23 over 482 randomly selected reservoirs dispersed throughout the USA. The IRHI reflected five impairment factors including siltation, structural habitat, eutrophication, water regime, and aquatic plants. The factors were weakly related to key reservoir characteristics including reservoir area, depth, age, and usetype, suggesting that common reservoir descriptors are poor predictors of fish habitat impairment. The IRHI is rapid and inexpensive to calculate, provides an easily understood measure of the overall habitat impairment, allows comparison of reservoirs and therefore prioritization of restoration activities, and may be used to track restoration progress. The major limitation of the IRHI is its reliance on unstandardized professional judgment rather than standardized empirical measurements. ?? 2010 US Government.

Miranda, L. E.; Hunt, K. M.

2011-01-01

391

Eder Acquisition 2007 Habitat Evaluation Procedures Report.  

SciTech Connect

A habitat evaluation procedures (HEP) analysis was conducted on the Eder acquisition in July 2007 to determine how many protection habitat units to credit Bonneville Power Administration (BPA) for providing funds to acquire the project site as partial mitigation for habitat losses associated with construction of Grand Coulee and Chief Joseph Dams. Baseline HEP surveys generated 3,857.64 habitat units or 1.16 HUs per acre. HEP surveys also served to document general habitat conditions. Survey results indicated that the herbaceous plant community lacked forbs species, which may be due to both livestock grazing and the late timing of the surveys. Moreover, the herbaceous plant community lacked structure based on lower than expected visual obstruction readings (VOR); likely a direct result of livestock impacts. In addition, introduced herbaceous vegetation including cultivated pasture grasses, e.g. crested wheatgrass and/or invader species such as cheatgrass and mustard, were present on most areas surveyed. The shrub element within the shrubsteppe cover type was generally a mosaic of moderate to dense shrubby areas interspersed with open grassland communities while the 'steppe' component was almost entirely devoid of shrubs. Riparian shrub and forest areas were somewhat stressed by livestock. Moreover, shrub and tree communities along the lower reaches of Nine Mile Creek suffered from lack of water due to the previous landowners 'piping' water out of the stream channel.

Ashley, Paul R.

2008-01-01

392

Habitat use and movement of the endangered Arroyo Toad (Anaxyrus californicus) in coastal southern California  

USGS Publications Warehouse

Information on the habitat use and movement patterns of Arroyo Toads (Anaxyrus californicus) is limited. The temporal and spatial characteristics of terrestrial habitat use, especially as it relates to upland use in coastal areas of the species' range, are poorly understood. We present analyses of radiotelemetry data from 40 individual adult toads tracked at a single site in coastal southern California from March through November of 2004. We quantify adult Arroyo Toad habitat use and movements and interpret results in the context of their life history. We show concentrated activity by both male and female toads along stream terraces during and after breeding, and, although our fall sample size is low, the continued presence of adult toads in the floodplain through the late fall. Adult toads used open sandy flats with sparse vegetation. Home-range size and movement frequency varied as a function of body mass. Observed spatial patterns of movement and habitat use both during and outside of the breeding period as well as available climatological data suggest that overwintering of toads in floodplain habitats of near-coastal areas of southern California may be more common than previously considered. If adult toads are not migrating out of the floodplain at the close of the breeding season but instead overwinter on stream terraces in near-coastal areas, then current management practices that assume toad absence from floodplain habitats may be leaving adult toads over-wintering on stream terraces vulnerable to human disturbance during a time of year when Arroyo Toad mortality is potentially highest.

Elizabeth Gallegos;Lisa M Lyren;Lovich, E , Robert;Milan J Mitrovich;Robert N Fisher;Robert N Fisher

2011-01-01

393

Consistency in habitat preference of forest bird species  

USGS Publications Warehouse

The important management conclusion that follows from our results is that the habitat requirements of most forest bird species, although quite specific for each species, apply generally throughout their breeding ranges. Thus a habitat management program that proves beneficial in one part of the breeding range of a species has a high likelihood of success in an area hundreds of kilometers away. Site-specific programs may be necessary for successful management of species whose habitat preferences change across their range. Alternatively, geographical variation in habitat use may indicate that a species' habitat requirements are easily met and that effective management for the species is more readily attained. Close monitoring of a species' response to specific management programs will be required to resolve whether species showing geographic variation in habitat preference are habitat specialists or simply habitat generalists with varying responses to habitat structure

Noon, B.R.; Dawson, D.K.; Inkley, D.B.; Robbins, C.S.; Anderson, S.H.

1980-01-01

394

Spatial analysis of habitat selection by Sitka black-tailed deer in Southeast Alaska, USA  

NASA Astrophysics Data System (ADS)

We used a vector-based geographic information system (GIS) to examine habitat selection by radiocollared Sitka black-tailed deer ( Odocoileus hemionus sitkensis) in logged forests of southeast Alaska. Our main objective was to explain deer habitat selection relative to old-growth/clear-cut edges and edge habitats at two different spatial scales. Deer home ranges contained higher percentages of recent clear-cuts (50-69%) than the study area (37%; P<0.01) and had higher old-growth/clear-cut edge densities than expected by chance ( P<0.01). Deer relocation points were closer to old-growth/clear-cut edges (average=135 m) than random points located within each deer's relocation area (average=168 m; P=0.05). Likewise, deer relocations were closer to old-growth/clear-cut edges than points randomly located within old-growth stands or recent clear-cuts ( P<0.01). As the size of clear-cuts increased, both deer relocation density and the proportion of a clear-cut occupied by deer home ranges decreased. Because old growth is important deer habitat and clear-cuts can produce deer forage for only 20-30 years after logging in southeast Alaska, deer management plans such as preserving entire watersheds and maintaining mixes of old growth and recent clear-cut have been proposed. Our data suggest that deer need a diversity of habitats near each other within their home ranges.

Chang, Kang-Tsung; Verbyla, David L.; Yeo, Jeffrey J.

1995-07-01

395

Local Abundance Patterns of Noctuid Moths in Olive Orchards: Life-History Traits, Distribution Type and Habitat Interactions  

PubMed Central

Local species abundance is related to range size, habitat characteristics, distribution type, body size, and life-history variables. In general, habitat generalists and polyphagous species are more abundant in broad geographical areas. Underlying this, local abundance may be explained from the interactions between life-history traits, chorological pattern, and the local habitat characteristics. The relationship within taxa between life-history traits, distribution area, habitat characteristics, and local abundance of the noctuid moth (Lepidoptera: Noctuidae) assemblage in an olive orchard, one of the most important agro-ecosystems in the Mediterranean basin, was analyzed. A total of 66 species were detected over three years of year-round weekly samplings using the light-trap method. The life-history traits examined and the distribution type were found to be related to the habitat-species association, but none of the biological strategies defined from the association to the different habitats were linked with abundance. In contrast to general patterns, dispersal ability and number of generations per year explained differences in abundance. The relationships were positive, with opportunistic taxa that have high mobility and several generations being locally more abundant. In addition, when the effect of migrant species was removed, the distribution type explained abundance differences, with Mediterranean taxa (whose baricenter is closer to the studied area) being more abundant.

Perez-Guerrero, Sergio; Redondo, Alberto Jose; Yela, Jose Luis

2011-01-01

396

Habitat connectivity and ecosystem productivity: implications from a simple model.  

USGS Publications Warehouse

The import of resources (food, nutrients) sustains biological production and food webs in resource-limited habitats. Resource export from donor habitats subsidizes production in recipient habitats, but the ecosystem-scale consequences of resource translocation are generally unknown. Here, I use a nutrient-phytoplankton-zooplankton model to show how dispersive connectivity between a shallow autotrophic habitat and a deep heterotrophic pelagic habitat can amplify overall system production in metazoan food webs. This result derives from the finite capacity of suspension feeders to capture and assimilate food particles: excess primary production in closed autotrophic habitats cannot be assimilated by consumers; however, if excess phytoplankton production is exported to food-limited heterotrophic habitats, it can be assimilated by zooplankton to support additional secondary production. Transport of regenerated nutrients from heterotrophic to autotrophic habitats sustains higher system primary production. These simulation results imply that the ecosystem-scale efficiency of nutrient transformation into metazoan biomass can be constrained by the rate of resource exchange across habitats and that it is optimized when the transport rate matches the growth rate of primary producers. Slower transport (i.e., reduced connectivity) leads to nutrient limitation of primary production in autotrophic habitats and food limitation of secondary production in heterotrophic habitats. Habitat fragmentation can therefore impose energetic constraints on the carrying capacity of aquatic ecosystems. The outcomes of ecosystem restoration through habitat creation will be determined by both functions provided by newly created aquatic habitats and the rates of hydraulic connectivity between them.

Cloern, J. E.

2007-01-01

397

Habitat connectivity and ecosystem productivity: implications from a simple model.  

PubMed

The import of resources (food, nutrients) sustains biological production and food webs in resource-limited habitats. Resource export from donor habitats subsidizes production in recipient habitats, but the ecosystem-scale consequences of resource translocation are generally unknown. Here, I use a nutrient-phytoplankton-zooplankton model to show how dispersive connectivity between a shallow autotrophic habitat and a deep heterotrophic pelagic habitat can amplify overall system production in metazoan food webs. This result derives from the finite capacity of suspension feeders to capture and assimilate food particles: excess primary production in closed autotrophic habitats cannot be assimilated by consumers; however, if excess phytoplankton production is exported to food-limited heterotrophic habitats, it can be assimilated by zooplankton to support additional secondary production. Transport of regenerated nutrients from heterotrophic to autotrophic habitats sustains higher system primary production. These simulation results imply that the ecosystem-scale efficiency of nutrient transformation into metazoan biomass can be constrained by the rate of resource exchange across habitats and that it is optimized when the transport rate matches the growth rate of primary producers. Slower transport (i.e., reduced connectivity) leads to nutrient limitation of primary production in autotrophic habitats and food limitation of secondary production in heterotrophic habitats. Habitat fragmentation can therefore impose energetic constraints on the carrying capacity of aquatic ecosystems. The outcomes of ecosystem restoration through habitat creation will be determined by both functions provided by newly created aquatic habitats and the rates of hydraulic connectivity between them. PMID:17206578

Cloern, James E

2007-01-01

398

How Well Can We Predict Salmonid Spawning Habitat with LiDAR?  

NASA Astrophysics Data System (ADS)

Suitable salmonid spawning habitat is, to a great extent, determined by physical, landscape driven characteristics such as channel morphology and grain size. Identifying reaches with high-quality spawning habitat is essential to restoration efforts in areas where salmonid species are endangered or threatened. While both predictions of suitable habitat and observations of utilized habitat are common in the literature, they are rarely combined. Here we exploit a unique combination of high-resolution LiDAR data and seven years of 387 individually surveyed Coho and Steelhead redds in Scott Creek, a 77 km2 un-glaciated coastal California drainage in the Santa Cruz Mountains, to both make and test predictions of spawning habitat. Using a threshold channel assumption, we predict grain size throughout Scott Creek via a shear stress model that incorporates channel width, instead of height, using Manning's equation (Snyder et al., 2013). Slope and drainage area are computed from a LiDAR-derived DEM, and channel width is calculated via hydraulic modeling. Our results for median grain size predictions closely match median grain sizes (D50) measured in the field, with the majority of sites having predicted D50's within a factor of two of the observed values, especially for reaches with D50 > 0.02m. This success suggests that the threshold model used to predict grain size is appropriate for un-glaciated alluvial channel systems. However, it appears that grain size alone is not a strong predictor of salmon spawning. Reaches with a high (>0.1m) average predicted D50 do have lower redd densities, as expected based on spawning gravel sizes in the literature. However, reaches with lower (<0.1m) predicted D50 have a wide range of redd densities, suggesting that reach-average grain size alone cannot explain spawning site selection in the finer-grained reaches of Scott Creek. We turn to analysis of bedform morphology in order to explain the variation in redd density in the low-slope, finer-grained reaches of Lower Scott Creek. Because spawning is strongly correlated with riffle locations, we use a LiDAR-derived longitudinal profile to predict where riffle habitat is located within the watershed. To accomplish this, we use previous studies that constrain pool-riffle habitat to slopes <1.5%, then use wavelet analysis of the longitudinal profile within these pool-riffle reaches to investigate the spacing of drops in water surface slope, with the goal of identifying reaches with high riffle density. Our slope-based predictions of pool-riffle morphology closely match the extent of pool-riffle reaches observed in the field. Average redd density in pool-riffle reaches is more than double the average redd density in reaches of other channel morphologies. Initial wavelet analysis suggests that riffle spacing may be longer in the lower reaches of Scott Creek and shorter in the high-redd density upper reaches, a finding that agrees with the hypothesis that spawning habitat is limited by riffle density. Our results suggest that high resolution topographic data can be successfully used to identify reaches of utilized spawning habitat based on grain size predictions and wavelet analysis of bedform spacing.

Pfeiffer, A.; Finnegan, N. J.; Hayes, S.

2013-12-01

399

Predicted changes in subyearling fall Chinook salmon rearing and migratory habitat under two drawdown scenarios for John Day Reservoir, Columbia River  

USGS Publications Warehouse

We evaluated the potential effects of two different drawdown scenarios on rearing and migration habitat of subyearling fall Chinook salmon Oncorhynchus tshawytscha in John Day Reservoir on the Columbia River. We compared habitats at normal operating pool elevation with habitats at drawdown to spillway crest elevation and drawdown to the historical natural river elevation for two flows (4,417 and 8,495 m3/s). Using two-dimensional hydrodynamic modeling and a predictive habitat model, we determined the quantity and spatial distribution of rearing habitat and predicted water velocities. We predicted that the most habitat area would occur under normal pool elevation, but 93% of habitat was located in the upper third of the reservoir. Although less habitat area was predicted under drawdown to the spillway crest and the natural river, it was distributed more homogeneously throughout the study area. Habitat connectivity, patch size, and percent of suitable shoreline were greatest under drawdown to the natural river elevation. Mean cross-sectional water velocity and the variation in velocity increased with increasing level of reservoir drawdown. Water velocities under drawdown to the natural river were about twice as high as those under drawdown to spillway crest and five times higher than those under normal pool. The variability in water velocity, which may provide cues to fish migration, was highest under drawdown to the natural river and lowest under normal pool elevation. The extent to which different drawdown scenarios would be effective in John Day Reservoir depends in part on restoring normative riverine processes.

Tiffan, K. F.; Garland, R. D.; Rondorf, D. W.

2006-01-01

400

How habitat disturbance benefits geckos: Conservation implications.  

PubMed

I here provide some field observations and literature data showing that egg laying site availability could be the main limiting factor for most arboreal gecko population dynamics. Several natural (typhoons, volcanism, sea level variations) or human-mediated habitat modifications (garden openings in forested areas) provide enough habitat disturbances to significantly increase reproductive outputs in island gecko populations. Such observations, however, also apply to continental populations. Our observations suggest that artificial shelter and egg laying site creation could easily allow populations to increase and also supply easier access to arboreal species for ecological or biodiversity studies. Furthermore, our observations also point out that occurrence in man-made habitats and genetic uniformity of most widespread island lizards should not be considered as evidence of their recent introduction through human agency. PMID:20176340

Ineich, Ivan

2010-01-01

401

Landscape habitat diversity: An information theoretic measure  

SciTech Connect

Biotic diversity is a topic of increasing concern, but current tools for quantifying diversity at the landscape level are inadequate. A new index is proposed. Beginning with a classified raster image of a landscape, each habitat type is assigned a value based on an ordination axis distance. The change in value from one patch to the next depends on how similar the two patches are. An information measure d{sub I} is used to evaluate deviation from uniformity of the ordination values at different scales. Different areas can be compared if habitat values are based on the same ordination scale. This new method provides a powerful tool for both displaying and calculating landscape habitat diversity.

Loehle, C. [Argonne National Lab., IL (United States); Wein, G. [Memphis State Univ., TN (United States). Dept. of Biology

1994-06-01

402

Host specialization in habitat specialists and generalists.  

PubMed

Generalists and specialists use different cues to find their habitat and essential resources. While generalists have the advantage of exploiting a wider range of resources, they are predicted to be less efficient in using one particular resource compared to specialists. The level of specialization of parasitoids can be either at the habitat or at the host level; strategies used by either type are expected to differ. We examined interactions between three aphid parasitoid species that are a habitat specialist Aphidius rhopalosiphi, a habitat generalist Aphidius ervi, and a host generalist Praon volucre on three cereal aphids, Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi. We compared total parasitism rate across behavioral and physiological variation in a non-choice test. Next, we addressed total parasitism in two phases to examine: (1) the response of parasitoids to different hosts through the behavioral sequence from antennation through oviposition, and (2) the physiological suitability of different hosts for oviposition and larval development. Parasitization typically involved the following behavioral steps: (1) antennal contact, (2) abdominal bending, and (3) ovipositor insertion (acceptance). A. rhopalosiphi had the same number of antennal contacts with the three aphids but showed fewer instances of abdominal bending towards R. padi. Pre-contact host preference was found for A. ervi but it did not correspond to the level of acceptance. The number of antennal contacts by P. volucre corresponded to the parasitization level of the aphid species but more mummies were produced on M. dirhodum than on R. padi. These results suggest that parasitoid species that are habitat specialists react similarly to the different host species present in the same habitat, whereas generalist species exhibit clear preferences during host selection. Preferences were, however, not always related to host suitability. PMID:18443827

Stilmant, Didier; Van Bellinghen, Cécile; Hance, Thierry; Boivin, Guy

2008-07-01

403

Omicron space habitat—research stage II  

NASA Astrophysics Data System (ADS)

The design presented in this paper is in response to the revolution in private space activities, the increasing public interest in commercial flights to space and the utilization of structures such as space hotels or private orbital habitats. The baseline for the Omicron design concept is the Russian Salyut derived space station module. Salyut was the first space station to orbit the Earth. Its unique design and technical features were what made the development of space stations Salyut 1-7, MIR and the International Space Station (ISS) Zwezda service module possible. Due to its versatility and the reliable operating launch vehicle Proton, this space module series has the potential to be adapted for space hotel development. This paper proposes a conceptual design of the space habitat called Omicron, with particular focus on interior design for the microgravity environment. The Omicron concepts address the needs of space tourism with a strong emphasis on the safety and comfort of the spaceflight participants. The Omicron habitat supports three inhabitants in nominal conditions (e.g., two passengers and one astronaut). The habitat provides a flexible interior, facilities and spaces dynamically transforming in order to accommodate various types of activities, which will be performed in an organically formed interior supporting spatial orientation and movement in microgravity. The future development potential of Omicron is also considered. The baseline version is composed solely of one rigid module with an inverted cupola for observations. An alternative version offers more space using an inflatable structure. Finally, a combination of multiple Omicron modules enables the creation of a larger orbital habitat. The Omicron's subsystems support a few days visit by trained passengers. The transport to the habitat would be provided e.g., by the Soyuz TMA spacecraft carried by the Soyuz launch vehicle in the early stage of Omicron's development, before a fully reusable spacecraft would be available.

Doule, Ond?ej; Šálený, Vratislav; Hérin, Benoît; Rousek, Tomáš

2012-01-01

404

Design, Analysis and Fabrication of Secondary Structural Components for the Habitat Demonstration Unit-Deep Space Habitat  

NASA Technical Reports Server (NTRS)

In support of NASA s Habitat Demonstration Unit - Deep Space Habitat Prototype, a number of evolved structural sections were designed, fabricated, analyzed and installed in the 5 meter diameter prototype. The hardware consisted of three principal structural sections, and included the development of novel fastener insert concepts. The articles developed consisted of: 1) 1/8th of the primary flooring section, 2) an inner radius floor beam support which interfaced with, and supported (1), 3) two upper hatch section prototypes, and 4) novel insert designs for mechanical fastener attachments. Advanced manufacturing approaches were utilized in the fabrication of the components. The structural components were developed using current commercial aircraft constructions as a baseline (for both the flooring components and their associated mechanical fastener inserts). The structural sections utilized honeycomb sandwich panels. The core section consisted of 1/8th inch cell size Nomex, at 9 lbs/cu ft, and which was 0.66 inches thick. The facesheets had 3 plys each, with a thickness of 0.010 inches per ply, made from woven E-glass with epoxy reinforcement. Analysis activities consisted of both analytical models, as well as initial closed form calculations. Testing was conducted to help verify analysis model inputs, as well as to facilitate correlation between testing and analysis. Test activities consisted of both 4 point bending tests as well as compressive core crush sequences. This paper presents an overview of this activity, and discusses issues encountered during the various phases of the applied research effort, and its relevance to future space based habitats.

Smith, Russell W.; Langford, William M.

2012-01-01

405

Structural Health System for Crew Habitats  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the history of JPL, and its affilation with CalTech and NASA. It continues by examining some of the sensors, and systems to ensure structural health that JPL has developed. It also reviews some of the habitat designs that are being developed for the lunar base. With these crew habitats, there is a requirement to have embedded systems health monitoring, to alert the crew in time about adverse structural conditions. The use of sensing technologies and smart materials are being developed to assure mechanical flexibility, minimumally invasive, autonomous, and enhanced reliability.

Brandon, Erik

2005-01-01

406

Portable Habitat for Antarctic Scientific Research (PHASR)  

NASA Technical Reports Server (NTRS)

The Portable Habitat for Antarctic Scientific Research, PHASR, is designed as a versatile, general purpose habitat system that addresses the problem of functional space and environmental soundness in a partially fabric-covered shelter. PHASR is used for remote field site applications that can be quickly deployed. PHASR will also provide four scientists with a comfortable and efficient use of interior space. PHASR is a NASA/USRA Advanced Design Program project conducted at the University of Houston College of Architecture, Sasadawa International Center for Space Architecture (SICSA). This report is prepared for NASA/USRA.

Griswold, Samantha S.

1992-01-01

407

Information to support to monitoring and habitat restoration on Ash Meadows National Wildlife Refuge  

USGS Publications Warehouse

The Ash Meadows National Wildlife Refuge staff focuses on improving habitat for the highest incidence of endemic species for an area of its size in the continental United States. Attempts are being made to restore habitat to some semblance of its pre-anthropogenic undisturbed condition, and to provide habitat conditions to which native plant and animal species have evolved. Unfortunately, restoring the Ash Meadows’ Oases to its pre-anthropogenic undisturbed condition is almost impossible. First, there are constraints on water manipulation because there are private holdings within the refuge boundary; second, there has been at least one species extinction—the Ash Meadows pool fish (Empetrichthys merriami). It is also quite possible that thermal endemic invertebrate species were lost before ever being described. Perhaps the primary obstacle to restoring Ash Meadows to its pre-anthropogenic undisturbed conditions is the presence of invasive species. However, invasive species, such as red swamp crayfish (Procambarus clarki) and western mosquitofish (Gambusia affinis), are a primary driving force in restoring Ash Meadows’ spring systems, because under certain habitat conditions they can all but replace native species. Returning Ash Meadows’ physical landscape to some semblance of its pre-anthropogenic undisturbed condition through natural processes may take decades. Meanwhile, the natural dissolution of concrete and earthen irrigation channels threatens to allow cattail marshes to flourish instead of spring-brooks immediately downstream of spring discharge. This successional stage favors non-native crayfish and mosquitofish over the native Amargosa pupfish (Cyprinodon nevadensis). Thus, restoration is needed to control non-natives and to promote native species, and without such intervention the probability of native fish reduction or loss, is anticipated. The four studies in this report are intended to provide information for restoring native fish habitat and for monitoring native fish populations in relation to restoration efforts on the Ash Meadows National Wildlife Refuge. There are no precise records on conditions of each of the spring systems prior to anthropogenic alteration; however, fostering conditions that favor native over non-natives will be key to habitat restoration. Information regarding native species carbon source is needed to create habitat that favors native species, thus habitat restoration fostering food stuff consumed by native species should be considered in restoration efforts. In compiling data for the first part of this report, we tracked carbon source for native and non-native species at four stations along the Jackrabbit Spring system. Thus, we were able to contrast carbon source in warm- and cool-water habitats. Habitat in Jackrabbit Spring was improved for native fishes in 2007. The second paper in this report focuses on native fish populations in Jackrabbit Spring system pre- and post-restoration. Much of the Ash Meadows Oases is marsh habitat where non-native red swamp crayfish and western mosquitofish are often abundant, to the detriment of non-natives. Because marsh habitat is broadly represented in the Ash Meadows landscape, establishing marsh habitat most conducive to the native fishes is important to the restoration effort, and the third paper addresses marsh habitat type with the relative abundance of fishes and crayfish. There are previous years of monitoring Ash Meadows’ native fish populations, but not all monitoring occurred at the same time of year. Desert-fish populations sometimes undergo seasonal fluctuation, so it might not be valid to compare population trends using difference seasons. For report four, we tracked a closed population of Amargosa pupfish (Cyprinodon nevadensis) year round to track seasonal trends. Knowledge of seasonal trends is important in tracking changes of populations pre- and post-restoration.

Scoppettone, G. Gary

2013-01-01

408

Fate of Heterotrophic Microbes in Pelagic Habitats: Focus on Populations  

PubMed Central

Major biogeochemical processes in the water columns of lakes and oceans are related to the activities of heterotrophic microbes, e.g., the mineralization of organic carbon from photosynthesis and allochthonous influx or its transport to the higher trophic levels. During the last 15 years, cultivation-independent molecular techniques have substantially contributed to our understanding of the diversity of the microbial communities in different aquatic systems. In parallel, the complexity of aquatic