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1

Host Life History Strategy, Species Diversity, and Habitat Influence Trypanosoma cruzi Vector Infection in Changing Landscapes  

PubMed Central

Background Anthropogenic land use may influence transmission of multi-host vector-borne pathogens by changing diversity, relative abundance, and community composition of reservoir hosts. These reservoir hosts may have varying competence for vector-borne pathogens depending on species-specific characteristics, such as life history strategy. The objective of this study is to evaluate how anthropogenic land use change influences blood meal species composition and the effects of changing blood meal species composition on the parasite infection rate of the Chagas disease vector Rhodnius pallescens in Panama. Methodology/Principal Findings R. pallescens vectors (N?=?643) were collected in different habitat types across a gradient of anthropogenic disturbance. Blood meal species in DNA extracted from these vectors was identified in 243 (40.3%) vectors by amplification and sequencing of a vertebrate-specific fragment of the 12SrRNA gene, and T. cruzi vector infection was determined by pcr. Vector infection rate was significantly greater in deforested habitats as compared to contiguous forests. Forty-two different species of blood meal were identified in R. pallescens, and species composition of blood meals varied across habitat types. Mammals (88.3%) dominated R. pallescens blood meals. Xenarthrans (sloths and tamanduas) were the most frequently identified species in blood meals across all habitat types. A regression tree analysis indicated that blood meal species diversity, host life history strategy (measured as rmax, the maximum intrinsic rate of population increase), and habitat type (forest fragments and peridomiciliary sites) were important determinants of vector infection with T. cruzi. The mean intrinsic rate of increase and the skewness and variability of rmax were positively associated with higher vector infection rate at a site. Conclusions/Significance In this study, anthropogenic landscape disturbance increased vector infection with T. cruzi, potentially by changing host community structure to favor hosts that are short-lived with high reproductive rates. Study results apply to potential environmental management strategies for Chagas disease. PMID:23166846

Gottdenker, Nicole L.; Chaves, Luis Fernando; Calzada, Jose E.; Saldana, Azael; Carroll, C. Ronald

2012-01-01

2

Habitats of Life  

NASA Astrophysics Data System (ADS)

There are four principal habitats in which life may exist - the surface of a planetary body, its subsurface, its atmosphere and space. From our own experience we know that life does exist on the surface of a planet, in its subsurface, and transiently at least in the atmosphere. Where it is present, it exists in a surprising diversity and in a variety of microhabitats, from deep caverns (Hose et al. 2000, Melim et al. 2001) to hydrothermal fluids and hot springs of various chemistries (Jannasch 1995, Rzonca and Schulze-Makuch 2002), to the frozen deserts of Antarctica (Friedmann 1982, Sun and Friedmann 1999). In this chapter we will elaborate on the principal habitats, the constraints they impose on life, and the possibilities they provide.

Dirk, Schulze-Makuch; Irwin, Louis N.

3

Concurrent habitat and life history influences on effective/census population size ratios in stream-dwelling trout.  

PubMed

Lower effective sizes (N(e)) than census sizes (N) are routinely documented in natural populations, but knowledge of how multiple factors interact to lower N(e)/N ratios is often limited. We show how combined habitat and life-history influences drive a 2.4- to 6.1-fold difference in N(e)/N ratios between two pristine brook trout (Salvelinus fontinalis) populations occupying streams separated by only 750 m. Local habitat features, particularly drainage area and stream depth, govern trout biomass produced in each stream. They also generate higher trout densities in the shallower stream by favoring smaller body size and earlier age-at-maturity. The combination of higher densities and reduced breeding site availability in the shallower stream likely leads to more competition among breeding trout, which results in greater variance in individual reproductive success and a greater reduction in N(e) relative to N. A similar disparity between juvenile or adult densities and breeding habitat availability is reported for other species and hence may also result in divergent N(e)/N ratios elsewhere. These divergent N(e)/N ratios between adjacent populations are also an instructive reminder for species conservation programs that genetic and demographic parameters may differ dramatically within species. PMID:22822435

Belmar-Lucero, Sebastian; Wood, Jacquelyn L A; Scott, Sherylyne; Harbicht, Andrew B; Hutchings, Jeffrey A; Fraser, Dylan J

2012-03-01

4

Concurrent habitat and life history influences on effective/census population size ratios in stream-dwelling trout  

PubMed Central

Lower effective sizes (Ne) than census sizes (N) are routinely documented in natural populations, but knowledge of how multiple factors interact to lower Ne/N ratios is often limited. We show how combined habitat and life-history influences drive a 2.4- to 6.1-fold difference in Ne/N ratios between two pristine brook trout (Salvelinus fontinalis) populations occupying streams separated by only 750 m. Local habitat features, particularly drainage area and stream depth, govern trout biomass produced in each stream. They also generate higher trout densities in the shallower stream by favoring smaller body size and earlier age-at-maturity. The combination of higher densities and reduced breeding site availability in the shallower stream likely leads to more competition among breeding trout, which results in greater variance in individual reproductive success and a greater reduction in Ne relative to N. A similar disparity between juvenile or adult densities and breeding habitat availability is reported for other species and hence may also result in divergent Ne/N ratios elsewhere. These divergent Ne/N ratios between adjacent populations are also an instructive reminder for species conservation programs that genetic and demographic parameters may differ dramatically within species. PMID:22822435

Belmar-Lucero, Sebastian; Wood, Jacquelyn L A; Scott, Sherylyne; Harbicht, Andrew B; Hutchings, Jeffrey A; Fraser, Dylan J

2012-01-01

5

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

6

An Analysis of Hybrid Life Support Systems for Sustainable Habitats  

E-print Network

The design of sustainable habitats on Earth, on other planetary surfaces, and in space, has motivated strategic planning with respect to life support (LS) system technology development and habitat design. Such planning ...

Shaw, Margaret Miller

2014-01-01

7

Architecture and life support systems for a rotating space habitat  

Microsoft Academic Search

Life Support Systems are critical to sustain human habitation of space over long time periods. As orbiting space habitats become operational in the future, support systems such as atmo-sphere, food, water etc. will play a very pivotal role in sustaining life. To design a long-duration space habitat, it's important to consider the full gamut of human experience of the environment.

Gaurav Misra

2010-01-01

8

Effects of Life History Strategy on Fish Distribution and Use of Estuarine Salt Marsh and Shallow-Water Flat Habitats  

Microsoft Academic Search

To assess the potential for habitat isolation effects on estuarine nekton, we used two species with different dispersal abilities\\u000a and life history strategies, mummichog (Fundulus heteroclitus) and pinfish (Lagodon rhomboides) to examine: (1) distribution trends among estuarine shallow-water flat and various intertidal salt marsh habitats and (2)\\u000a the influence of salt marsh habitat size and isolation. Collections were conducted using

David L. Meyer; Martin H. Posey

2009-01-01

9

Developing closed life support systems for large space habitats  

NASA Technical Reports Server (NTRS)

In anticipation of possible large-scale, long-duration space missions which may be conducted in the future, NASA has begun to investigate the research and technology development requirements to create life support systems for large space habitats. An analysis suggests the feasibility of a regeneration of food in missions which exceed four years duration. Regeneration of food in space may be justified for missions of shorter duration when large crews must be supported at remote sites such as lunar bases and space manufacturing facilities. It is thought that biological components consisting principally of traditional crop and livestock species will prove to be the most acceptable means of closing the food cycle. A description is presented of the preliminary results of a study of potential biological components for large space habitats. Attention is given to controlled ecosystems, Russian life support system research, controlled-environment agriculture, and the social aspects of the life-support system.

Phillips, J. M.; Harlan, A. D.; Krumhar, K. C.

1978-01-01

10

Population sinks resulting from degraded habitats of an obligate life-history pathway.  

PubMed

Many species traverse multiple habitats across ecosystems to complete their life histories. Degradation of critical, life stage-specific habitats can therefore lead to population bottlenecks and demographic deficits in sub-populations. The riparian zone of waterways is one of the most impacted areas of the coastal zone because of urbanisation, deforestation, farming and livestock grazing. We hypothesised that sink populations can result from alterations of habitats critical to the early life stages of diadromous fish that use this zone, and tested this with field-based sampling and experiments. We found that for Galaxias maculatus, one of the most widely distributed fishes of the southern hemisphere, obligate riparian spawning habitat was very limited and highly vulnerable to disturbance across 14 rivers in New Zealand. Eggs were laid only during spring tides, in the highest tidally influenced vegetation of waterways. Egg survival increased to >90% when laid in three riparian plant species and where stem densities were great enough to prevent desiccation, compared to no survival where vegetation was comprised of other species or was less dense. Experimental exclusion of livestock, one of the major sources of riparian degradation in rural waterways, resulted in quick regeneration, a tenfold increase in egg laying by fish and a threefold increase in survival, compared to adjacent controls. Overall, there was an inverse relationship between river size and egg production. Some of the largest rivers had little or no spawning habitat and very little egg production, effectively becoming sink populations despite supporting large adult populations, whereas some of the smallest pristine streams produced millions of eggs. We demonstrate that even a wide-ranging species with many robust adult populations can be compromised if a stage-specific habitat required to complete a life history is degraded by localised or more diffuse impacts. PMID:21076966

Hickford, Michael J H; Schiel, David R

2011-05-01

11

Factors influencing habitat selection by arboreal pit vipers.  

PubMed

We studied factors influencing habitat selection by two arboreal species of pit viper, namely Trimeresurus malabaricus (Malabar pit viper) and T. gramineus (Bamboo pit viper). The macrohabitat of these species was classified as forest, forest edge, or open habitat. To determine microhabitat selection, a variety of features at every other snake location were measured. Whether or not the animal was found in a tree, the tree species, its height of perch, position on the branch (distal/ apical/middle), diameter of the branch, the tree canopy (thick/sparse) and vegetation of the area (thick/sparse) were recorded. Assessment of habitat was done to determine how patterns of habitat use vary seasonally. Shaded ambient (air) temperatures and humidity were recorded. Data pertaining to 90 individuals of T. malabaricus and 100 individuals of T. gramineus were recorded. Trimeresurus malabaricus selected home ranges that included areas with thick vegetation and were encountered at regions of higher altitude. Neither of the species was found in open habitats. Both of the species preferred diverse habitats and were spread over the entire available space during the monsoon; they did not show any preference for the perch height during different seasons. Males had a positive correlation between body mass and preferred perch diameter. The present study suggests that several factors play an important role in habitat selection by these arboreal pit vipers, thus making them highly habitat-specific. PMID:23317362

Sawant, Nitin S; Jadhav, Trupti D

2013-01-01

12

Measures of human influence in habitats of South Asian monkeys  

Microsoft Academic Search

Human disturbance of habitat has important consequences for the demography, the morbidity, the behavior, and ultimately the\\u000a survival of non-human primates. This paper is an effort to define, qualitatively, the potential influence of humans on monkey\\u000a habitats and behavior in South Asia. Four variables are proposed and scored on a fourpoint scale. These variables can be used\\u000a in comparisons within

Naomi Bishop; Sarah Blaffer Hrdy; Jane Teas; James Moore

1981-01-01

13

Habitat use and life history as predictors of bird responses to habitat change.  

PubMed

In theory the consideration of life-history characteristics should provide a way of making predictive generalizations about the responses of different species to environmental modification. Nevertheless, few studies have tested the validity of this assumption or attempted to apply it across large numbers of related species. We explored both quantitative and qualitative contrasts between species of waterbirds that have either expanded or contracted their ranges in southern Africa over the past 40 years to test the hypothesis that expansionists and contractionists, respectively, should share life-history characteristics and/or ecological attributes. Similarities and differences in life history and ecology were explored through multivariate statistics. Overall, life-history traits provided an inadequate explanation of whether species would be range expansionists or contractionists. By contrast, ecological attributes of species that related to habitat use correlated well with range changes. In particular, waterbird species that inhabit pans seemed to be preadapted to using human-made dams and impoundments. The ability of many species to use artificial wetlands has aided their westward range expansions into arid regions of southern Africa. By contrast, species that rely on vegetated wetlands and that require reeds for nesting were predisposed to range contraction because their habitats have been severely affected by agricultural development and urbanization. In direct contrast to range expansions, most range contractions were west to east, the eastward contraction reflected the high level of wetland loss and degradation in the eastern lowlands of South Africa. Based on analysis of ecological attributes of regional contractionists, several additional species were identified as of potential conservation concern, although such concern may not as yet have been expressed. PMID:18254860

Okes, Nicola C; Hockey, Philip A R; Cumming, Graeme S

2008-02-01

14

Brief report: designing life support systems for space habitats.  

PubMed

Permanent human presence in space beyond low Earth orbit (LEO) is now technically feasible. To achieve this goal several requirements must be met, which can be summarized as: technologies, facilities, organization, vision, and will. This paper describes a recently published NASA Reference Publication, "Designing for Human Presence in Space: An Introduction to Environmental Control and Life Support Systems" that addresses how to achieve the goal of permanent human presence in space, specifically, how to design and develop environmental control and life support systems (ECLSS) for space habitats. This includes the technologies that perform the required functions, the facilities where the systems will be developed, and the organization necessary to perform the numerous tasks efficiently. PMID:11538581

Wieland, P

1994-01-01

15

Brief report: designing life support systems for space habitats  

NASA Technical Reports Server (NTRS)

Permanent human presence in space beyond low Earth orbit (LEO) is now technically feasible. To achieve this goal several requirements must be met, which can be summarized as: technologies, facilities, organization, vision, and will. This paper describes a recently published NASA Reference Publication, "Designing for Human Presence in Space: An Introduction to Environmental Control and Life Support Systems" that addresses how to achieve the goal of permanent human presence in space, specifically, how to design and develop environmental control and life support systems (ECLSS) for space habitats. This includes the technologies that perform the required functions, the facilities where the systems will be developed, and the organization necessary to perform the numerous tasks efficiently.

Wieland, P.

1994-01-01

16

The Virtual Habitat - a tool for Life Support Systems optimization  

NASA Astrophysics Data System (ADS)

In the course of designing Life Support Systems (LSS) a great multitude of concepts for and various combinations of subsystems and components are developed. In order to find an optimal LSS solution, thus the right combination of subsystems, the parameters for the definition of the optimization itself have to be determined. The often times used Equivalent Systems Mass (ESM) based trade study approach for life support systems is well suited for phase A conceptual design evaluations. The ESM approach allows an efficient evaluation of LSS on a component or subsystem level. The necessary next step in the process is the design, evaluation and optimization of the LSS on a system level. For the system level LSS design a classic ESM-based trade study seems not to be able to provide the information that is necessary to evaluate the concept correctly. Important decisive criteria such as system stability, controllability and effectiveness are not represented in the ESM approach. These parameters directly and decisively impact the scientific efficiency of the crew, thereby the mission in total. Thus, for system level optimization these criteria must be included alongside the ESM in a new integral optimization method. In order to be able to apply such an integral criterion dynamic modeling of most involved LSS subsystems, especially of the human crew, is necessary. Only then the required information about the efficiency of the LSS, over time, e.g. the systems stability, becomes available. In an effort to establish a dynamic simulation environment for habitats in extreme environmental conditions, the "Virtual Habitat" tool is being developed by the Human Spaceflight Group of the Technische Universit¨t M¨nchen (TUM). The paper discussed here presents the concept of a u the virtual habitat simulation. It discusses in what way the simulation tool enables a prediction of system characteristics and required information demanded by an integral optimization criterion. In general the Virtual Habitat consists of four main modules each of which is subdivided into further, more detailed sub-modules. The four main modules of the simulation are the following: · Closed Environment Module (CEM)- monitoring of compounds in a closed environment · Crew Module (CM) - dynamic human simulation · Plant Module (PM) - dynamic plant simulation · P/C systems module (PCSM) - library of dynamic P/C subsystems The paper describes the character of each of the modules introducing the first results, which will be the first version of the metabolism, muscle and cardiovascular sub-modules of the crew module. In addition a dynamic closed environment module and the first dynamic plant model are presented and discussed. Further the modularity strategy and interfaceability of the submodels of the Virtual Habitat are discussed highlighting the resulting model limitations. Finally in the paper an outlook is given on the tasks remaining before the virtual habitat can be used to optimize life support systems on a system level. Among others the question of model correlation with existing simulations and data will be addressed.

Czupalla, Markus; Dirlich, Thomas; Harder, Jan; Pfeiffer, Matthias

17

Does habitat fragmentation influence nest predation in the shortgrass prairie?  

USGS Publications Warehouse

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

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

2001-01-01

18

Life history comparison of two terrestrial isopods in relation to habitat specialization  

Microsoft Academic Search

For many animal species, there is a relationship between life history strategies, as predicted by the r–K-selection theory, degree of habitat specialization and response to habitat alteration and loss. Here we compare two sympatric woodlice species with contrasting patterns of habitat use and geographical distribution. We predict that Atlantoscia floridana (Philosciidae), considered a habitat generalist, would exhibit the r-selected traits,

Aline Ferreira Quadros; Yves Caubet; Paula Beatriz Araujo

2009-01-01

19

Habitat complexity influences cascading effects of multiple predators.  

PubMed

Although multiple predator effects and trophic cascades have both been demonstrated in a wide variety of ecosystems, ecologists have yet to incorporate these studies into an experimental framework that also manipulates a common and likely important factor, spatial heterogeneity. We manipulated habitat complexity, the presence of two top predators (toadfish and blue crabs), and one intermediate predator (mud crabs) to determine whether habitat complexity influences the strength of multiple predator interactions across multiple trophic levels in experimental oyster reef communities. In the absence of toadfish, blue crabs caused significant mud crab mortality. Despite also directly consuming mud crabs, toadfish indirectly benefited this intermediate predator by decreasing blue crab consumption of mud crabs. Toadfish suppression of mud crab foraging activity, and thus decreased mud crab encounters with blue crabs, is likely responsible for this counterintuitive result. Contrary to previous investigations which suggest that more complex habitats reduce interference interactions among predators, reef complexity strengthened emergent multiple predator effects (MPEs) on mud crabs. The degree to which these MPEs cascaded down to benefit juvenile oysters (basal prey) depended on both habitat complexity and nonconsumptive effects derived from predator-predator interactions. Habitat complexity reduced the foraging efficiency of each crab species individually but released crab interference interactions when together, so that the two crabs collectively consumed more oysters on complex reefs. Regardless of reef complexity, toadfish consistently decreased consumption of oysters by both crab species individually and when together. Therefore, interactions between predator identity and habitat complexity structure trophic cascades on oyster reefs. Furthermore, these cascading effects of multiple predators were largely mediated by nonconsumptive effects in this system. PMID:19137947

Grabowski, Jonathan H; Hughes, A Randall; Kimbro, David L

2008-12-01

20

Does maternal oviposition site influence offspring dispersal to suitable habitat?  

PubMed

Orientation and dispersal to suitable habitat affects fitness in many animals, but the factors that govern these behaviors are poorly understood. In many turtle species, hatchlings must orient and disperse to suitable aquatic habitat immediately after emergence from subterranean nests. Thus, the location of nest sites relative to aquatic habitats ideally should be associated with the direction of hatchling dispersal. At our study site, painted turtles (Chrysemys picta) nest to the west (on an island) and east (on the mainland) of a wetland, which determines the direction that hatchlings must travel to reach suitable aquatic habitat. To determine if hatchling orientation is intrinsically influenced by the location where their mothers nest, we employed a two-part cross-fostering experiment in the field, whereby half the eggs laid in mainland nests were swapped with half the eggs laid in island nests. Moreover, because C. picta hatchlings overwinter inside their nests, we performed a second cross-fostering experiment to fully decouple the effects of (1) the maternally chosen nest location, (2) the embryonic developmental location, and (3) the overwinter location. We released hatchlings into a circular arena in the field and found that turtles generally dispersed in a westerly direction, regardless of the maternally chosen nest location and independent of the locations of embryonic development and overwintering. Although this westerly direction was towards suitable aquatic habitat, we could not distinguish whether naïve hatchling turtles (i) use environmental cues/stimuli to orient their movement, or (ii) have an intrinsic bias to orient west in the absence of stimuli. Nevertheless, these findings suggest that the orientation behavior of naïve hatchling turtles during terrestrial dispersal is not dependent upon the location of maternally-chosen nest sites. PMID:23196739

Warner, Daniel A; Mitchell, Timothy S

2013-07-01

21

Demographics, Life Cycle, Habitat Characterization and Transplant Methods for the Endangered Orchid, Spiranthes parksii Correll  

E-print Network

an estimated 379 S. parksii individuals and 44.7 ha of its habitat. Research has been funded to mitigate for this loss and includes documenting demographics, life cycle, local and landscape habitat, and on-site transplantation of S. parksii. Results found...

Hammons, Jonathan R.

2010-01-14

22

The Influence of Spawning Habitat on Natural Reproduction of Muskellunge in Wisconsin  

Microsoft Academic Search

Many of Wisconsin's native populations of muskellunge Esox masquinongy exhibit declining reproductive success and failing natural recruitment. As a result, self-sustaining populations of muskellunge are diminishing. This study focused on spawning habitat factors that influence egg development and survival and, consequently, the reproductive success of muskellunge. Muskellunge spawning habitat characteristics in lakes with self-sustaining populations were compared with spawning habitat

Sarah A. Zorn; Terry L. Margenau; James S. Diana; Clayton J. Edwards

1998-01-01

23

Salmon Life Histories, Habitats, and Food Webs in the Columbia River Estuary  

E-print Network

Salmon Life Histories, Habitats, and Food Webs in the Columbia River Estuary Daniel J. Bottom NOAA management efforts in the Columbia River estuary on behalf of salmon: (1) the estuary is irrelevant stocks throughout the Columbia River Basin. The Columbia River estuary contributes to salmon life history

24

Influences of livestock grazing on sage grouse habitat  

Microsoft Academic Search

Livestock grazing has been identified as one factor associated with the widespread decline and degradation of sage grouse (Centrocercus urophasianus) habitat. We identi- fied n= 17 positive and negative impacts of livestock on sage grouse and habitat. Little information is currently available concerning the directs impacts of livestock grazing on sage grouse habitat. Indirect impacts are better understood than direct

L. Beck; Dean L.. Mitchell

2000-01-01

25

PRIMARY RESEARCH PAPER The influence of littoral zone coarse woody habitat on home  

E-print Network

PRIMARY RESEARCH PAPER The influence of littoral zone coarse woody habitat on home range size: 22 November 2008 / Published online: 10 December 2008 Ã? Springer Science+Business Media B.V. 2008 Abstract Coarse woody habitat (CWH) may be a critical feature of lakes that influences fish distribu- tions

26

Human disturbance and stage-specific habitat requirements influence snowy plover site occupancy during the breeding season  

PubMed Central

Habitat use has important consequences for avian reproductive success and survival. In coastal areas with recreational activity, human disturbance may limit use of otherwise suitable habitat. Snowy plovers Charadrius nivosus have a patchy breeding distribution along the coastal areas on the Florida Panhandle, USA. Our goal was to determine the relative effects of seasonal human disturbance and habitat requirements on snowy plover habitat use. We surveyed 303 sites for snowy plovers, human disturbance, and habitat features between January and July 2009 and 2010. We made multiple visits during three different sampling periods that corresponded to snowy plover breeding: pre-breeding, incubation, and brood-rearing and used multi-season occupancy models to examine whether human disturbance, habitat features, or both influenced site occupancy, colonization (probability of transition from an unoccupied site to an occupied site), and extinction (probability of transition from an occupied site to an unoccupied site). Snowy plover site occupancy and colonization was negatively associated with human disturbance and site extinction was positively associated with human disturbance. Interdune vegetation had a negative effect on occupancy and colonization, indicating that plovers were less likely to use areas with uniform, dense vegetation among dunes. Also, dune shape, beach debris, and access to low-energy foraging areas influenced site occupancy, colonization, and extinction. Plovers used habitat based on beach characteristics that provided stage-specific resource needs; however, human disturbance was the strongest predictor of site occupancy. In addition, vegetation plantings used to enhance dune rehabilitation may negatively impact plover site occupancy. Management actions that decrease human disturbance, such as symbolic fencing and signage, may increase the amount of breeding habitat available to snowy plovers on the Florida Panhandle and in other areas with high human activity. The specific areas that require this protection may vary across snowy plover life history stages. PMID:23610630

Webber, Alyson F; Heath, Julie A; Fischer, Richard A

2013-01-01

27

Human disturbance and stage-specific habitat requirements influence snowy plover site occupancy during the breeding season.  

PubMed

Habitat use has important consequences for avian reproductive success and survival. In coastal areas with recreational activity, human disturbance may limit use of otherwise suitable habitat. Snowy plovers Charadrius nivosus have a patchy breeding distribution along the coastal areas on the Florida Panhandle, USA. Our goal was to determine the relative effects of seasonal human disturbance and habitat requirements on snowy plover habitat use. We surveyed 303 sites for snowy plovers, human disturbance, and habitat features between January and July 2009 and 2010. We made multiple visits during three different sampling periods that corresponded to snowy plover breeding: pre-breeding, incubation, and brood-rearing and used multi-season occupancy models to examine whether human disturbance, habitat features, or both influenced site occupancy, colonization (probability of transition from an unoccupied site to an occupied site), and extinction (probability of transition from an occupied site to an unoccupied site). Snowy plover site occupancy and colonization was negatively associated with human disturbance and site extinction was positively associated with human disturbance. Interdune vegetation had a negative effect on occupancy and colonization, indicating that plovers were less likely to use areas with uniform, dense vegetation among dunes. Also, dune shape, beach debris, and access to low-energy foraging areas influenced site occupancy, colonization, and extinction. Plovers used habitat based on beach characteristics that provided stage-specific resource needs; however, human disturbance was the strongest predictor of site occupancy. In addition, vegetation plantings used to enhance dune rehabilitation may negatively impact plover site occupancy. Management actions that decrease human disturbance, such as symbolic fencing and signage, may increase the amount of breeding habitat available to snowy plovers on the Florida Panhandle and in other areas with high human activity. The specific areas that require this protection may vary across snowy plover life history stages. PMID:23610630

Webber, Alyson F; Heath, Julie A; Fischer, Richard A

2013-04-01

28

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

29

The universe: a cryogenic habitat for microbial life.  

PubMed

Panspermia, an ancient idea, posits that microbial life is ubiquitous in the Universe. After several decades of almost irrational rejection, panspermia is at last coming to be regarded as a serious contender for the beginnings of life on our planet. Astronomical data is shown to be consistent with the widespread distribution of complex organic molecules and dust particles that may have a biological provenance. A minuscule (10(-21)) survival rate of freeze-dried bacteria in space is all that is needed to ensure the continual re-cycling of cosmic microbial life in the galaxy. Evidence that terrestrial life may have come from elsewhere in the solar system has accumulated over the past decade. Mars is seen by some as a possible source of terrestrial life, but some hundreds of billions of comets that enveloped the entire solar system, are a far more likely primordial reservoir of life. Comets would then have seeded Earth, Mars, and indeed all other habitable planetary bodies in the inner regions of the solar system. The implications of this point of view, which was developed in conjunction with the late Sir Fred Hoyle since the 1970s, are now becoming amenable to direct empirical test by studies of pristine organic material in the stratosphere. The ancient theory of panspermia may be on the verge of vindication, in which case the entire universe would be a grand crucible of cryomicrobiology. PMID:15094088

Wickramasinghe, Chandra

2004-04-01

30

Life history comparison of two terrestrial isopods in relation to habitat specialization  

NASA Astrophysics Data System (ADS)

For many animal species, there is a relationship between life history strategies, as predicted by the r- K-selection theory, degree of habitat specialization and response to habitat alteration and loss. Here we compare two sympatric woodlice species with contrasting patterns of habitat use and geographical distribution. We predict that Atlantoscia floridana (Philosciidae), considered a habitat generalist, would exhibit the r-selected traits, whereas Balloniscus glaber (Balloniscidae), considered a habitat specialist, should have the K-selected traits. We analyzed several life history traits as well as life and fecundity tables using 715 and 842 females of A. floridana and B. glaber, respectively, from populations living in syntopy in southern Brazil. As predicted, most evaluated traits allow A. floridana to be considered an r-strategist and B. glaber a K-strategist: A. floridana showed a shorter lifetime, faster development, earlier reproduction, a smaller parental investment, higher net reproductive rate ( R0), a higher growth rate ( r) and a shorter generation time ( T) in comparison to B. glaber. A. floridana seems to be a successful colonizer with a high reproductive output. These characteristics explain its local abundance, commonness and wide geographical distribution. On the contrary, B. glaber has a restricted geographical distribution that is mainly associated with Atlantic forest fragments, a biome threatened by deforestation and replacement by monocultures. Its narrow distribution combined with the K-selected traits may confer to this species an increased extinction risk.

Quadros, Aline Ferreira; Caubet, Yves; Araujo, Paula Beatriz

31

Underground Habitats in the Río Tinto Basin: A Model for Subsurface Life Habitats on Mars  

Microsoft Academic Search

A search for evidence of cryptic life in the subsurface region of a fractured Paleozoic volcanosedimentary deposit near the source waters of the Río Tinto River (Iberian pyrite belt, southwest Spain) was carried out by Mars Astrobiology Research and Technology Experiment (MARTE) project investigators in 2003 and 2004. This conventional deep-drilling experiment is referred to as the MARTE ground truth

David C. Fernández-Remolar; Olga Prieto-Ballesteros; Nuria Rodríguez; Felipe Gómez; Ricardo Amils; Javier Gómez-Elvira; Carol R. Stoker

2008-01-01

32

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

33

Vocal and Visual Conspecific Cues Influence the Behavior of Chimney Swifts at Provisioned Habitat  

Microsoft Academic Search

Numerous species use socially derived information from conspecifics to evaluate the quality of potential habitat. We examine whether conspecific cues influence Chimney Swift (Chaetura pelagica) behavior at uninhabited provisioned habitat, and whether their response in the pre- and post-breeding seasons differs. We used conspecific playbacks and decoys at 19 towers designed for the swift's nesting in southern Ontario, Canada, and

Leah Finity; Joseph J. Nocera

2012-01-01

34

Influence of Mowing Artemisia tridentata ssp. wyomingensis on Winter Habitat for Wildlife  

Microsoft Academic Search

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter habitat for wildlife is lacking. This information is crucial because many wildlife species depended on

Kirk W. Davies; Jonathan D. Bates; Dustin D. Johnson; Aleta M. Nafus

2009-01-01

35

Habitat context influences predator interference interactions and the strength of resource partitioning.  

PubMed

Despite increasing evidence that habitat structure can shape predator-prey interactions, few studies have examined the impact of habitat context on interactions among multiple predators and the consequences for combined foraging rates. We investigated the individual and combined effects of stone crabs (Menippe mercenaria) and knobbed whelks (Busycon carica) when foraging on two common bivalves, the hard clam (Mercenaria mercenaria) and the ribbed mussel (Geukensia demissa) in oyster reef and sand flat habitats. Because these species co-occur across these and other estuarine habitats of varying physical complexity, this system is ideal for examining how habitat context influences foraging rates and the generality of predator interactions. Consistent with results from previous studies, consumption rates of each predator in isolation from the other were higher in the sand flat than in the more structurally complex oyster reef habitat. However, consumption by the two predators when combined surprisingly did not differ between the two habitats. This counterintuitive result probably stems from the influence of habitat structure on predator-predator interactions. In the sand-flat habitat, whelks significantly reduced their consumption of their less preferred prey when crabs were present. However, the structurally more complex oyster reef habitat appeared to reduce interference interactions among predators, such that consumption rates when the predators co-occurred did not differ from predation rates when alone. In addition, both habitat context and predator-predator interactions increased resource partitioning by strengthening predator dietary selectivity. Thus, an understanding of how habitat characteristics such as physical complexity influence interactions among predators may be critical to predicting the effects of modifying predator populations on their shared prey. PMID:16705438

Hughes, A Randall; Grabowski, Jonathan H

2006-08-01

36

INVERTEBRATE PRODUCTIVITY IN A SUBTROPICAL BLACKWATER RIVER: THE IMPORTANCE OF HABITAT AND LIFE HISTORY  

Microsoft Academic Search

Habitat and life history are critical elements in assessing the production dynamics of invertebrates and their role in aquatic ecosystems. We studied invertebrate productivity at two sites in a subtropical blackwater river (the Satilla) in the Lower Coastal Plain of Georgia, USA, and found that submerged wooden substrates, or snags, are heavily colonized by aquatic insects. We compared invertebrate productivity

ARTHUR C. BENKE; THOMAS C. VAN; DAVID M. GILLESPIE; FRED K. PARRISH

1984-01-01

37

Fluorine-Rich Planetary Environments as Possible Habitats for Life  

PubMed Central

In polar aprotic organic solvents, fluorine might be an element of choice for life that uses selected fluorinated building blocks as monomers of choice for self-assembling of its catalytic polymers. Organofluorine compounds are extremely rare in the chemistry of life as we know it. Biomolecules, when fluorinated such as peptides or proteins, exhibit a “fluorous effect”, i.e., they are fluorophilic (neither hydrophilic nor lipophilic). Such polymers, capable of creating self-sorting assemblies, resist denaturation by organic solvents by exclusion of fluorocarbon side chains from the organic phase. Fluorous cores consist of a compact interior, which is shielded from the surrounding solvent. Thus, we can anticipate that fluorine-containing “teflon”-like or “non-sticking” building blocks might be monomers of choice for the synthesis of organized polymeric structures in fluorine-rich planetary environments. Although no fluorine-rich planetary environment is known, theoretical considerations might help us to define chemistries that might support life in such environments. For example, one scenario is that all molecular oxygen may be used up by oxidation reactions on a planetary surface and fluorine gas could be released from F-rich magma later in the history of a planetary body to result in a fluorine-rich planetary environment.

Budisa, Nediljko; Kubyshkin, Vladimir; Schulze-Makuch, Dirk

2014-01-01

38

Species diversity and persistence in restored and remnant tallgrass prairies of North America: a function of species' life history, habitat type, or sampling bias?  

PubMed

1. The re-assembly of native animal communities in restored landscapes is a relatively unexplored phenomenon for many taxa. Specifically, ecologists lack the ability to generalize about how species traits, habitat size, habitat type (here, remnant prairie vs. restored grassland), and temporal variation interact to affect species diversity or species' persistence probabilities. 2. To investigate these relationships, moth communities from 10 prairie remnants and restorations were sampled over a 3-year interval and a combination of NMDS ordination, logistic regression, and repeated measures anova were used to test hypotheses regarding how life history variables and habitat characteristics determine the degree to which restored habitats develop a moth fauna similar to remnants. 3. Within sampling years, restored tallgrass prairies that were >or= 7 years old possessed lepidopteran species assemblages that were generally similar to those in prairie remnants. Community similarity, however, was driven by common moth species likely to also occur in the surrounding agricultural habitat. Species persistence was significantly influenced by a series of trait combinations identified using principal components analysis. Temporal variation independent of habitat type or patch size was the most significant determination of variation in species composition among sites. 4. These results suggest that lepidopteran persistence in restored landscapes is at least partially determined by species' life history attributes. The correlation between sampling year and species richness suggests that both weather effects on species voltinism and interannual differences in sampling bias may make it difficult for land managers to detect changes in species abundance following disturbance or habitat management. 5. Species may not necessarily possess specific life history traits that reduce extinction risk or enhance recolonization probabilities in the highly modified agricultural landscape of the Midwestern USA. Rather, voltinism, fecundity, body size, and host plant specialization may influence the ability of species to maintain populations in the greater agricultural landscape or to escape mass mortality following disturbances imposed by prairie management. PMID:18284475

Summerville, Keith S

2008-05-01

39

The search for life on Europa: limiting environmental factors, potential habitats, and Earth analogues.  

PubMed

The putative ocean of Europa has focused considerable attention on the potential habitats for life on Europa. By generally clement Earth standards, these Europan habitats are likely to be extreme environments. The objectives of this paper were to examine: (1) the limits for biological activity on Earth with respect to temperature, salinity, acidity, desiccation, radiation, pressure, and time; (2) potential habitats for life on Europa; and (3) Earth analogues and their limitations for Europa. Based on empirical evidence, the limits for biological activity on Earth are: (1) the temperature range is from 253 to 394 K; (2) the salinity range is a(H2O) = 0.6-1.0; (3) the desiccation range is from 60% to 100% relative humidity; (4) the acidity range is from pH 0 to 13; (5) microbes such as Deinococcus are roughly 4,000 times more resistant to ionizing radiation than humans; (6) the range for hydrostatic pressure is from 0 to 1,100 bars; and (7) the maximum time for organisms to survive in the dormant state may be as long as 250 million years. The potential habitats for life on Europa are the ice layer, the brine ocean, and the seafloor environment. The dual stresses of lethal radiation and low temperatures on or near the icy surface of Europa preclude the possibility of biological activity anywhere near the surface. Only at the base of the ice layer could one expect to find the suitable temperatures and liquid water that are necessary for life. An ice layer turnover time of 10 million years is probably rapid enough for preserving in the surface ice layers dormant life forms originating from the ocean. Model simulations demonstrate that hypothetical oceans could exist on Europa that are too cold for biological activity (T < 253 K). These simulations also demonstrate that salinities are high, which would restrict life to extreme halophiles. An acidic ocean (if present) could also potentially limit life. Pressure, per se, is unlikely to directly limit life on Europa. But indirectly, pressure plays an important role in controlling the chemical environments for life. Deep ocean basins such as the Mariana Trench are good analogues for the cold, high-pressure ocean of Europa. Many of the best terrestrial analogues for potential Europan habitats are in the Arctic and Antarctica. The six factors likely to be most important in defining the environments for life on Europa and the focus for future work are liquid water, energy, nutrients, low temperatures, salinity, and high pressures. PMID:14987483

Marion, Giles M; Fritsen, Christian H; Eicken, Hajo; Payne, Meredith C

2003-01-01

40

Habitat productivity influences root mass vertical distribution in grazed Mediterranean ecosystems  

NASA Astrophysics Data System (ADS)

Herbivores are expected to influence grassland ecosystems by modifying root biomass and root spatial distribution of plant communities. Studies in perennial dominated grasslands suggest that grazing intensity and primary productivity may be strong determinants of the vertical distribution of subterranean biomass. However, no studies have addressed this question in annual dominated pastures. In this study we assess the effect of grazing and habitat productivity on the vertical distribution of root mass in an annual dominated Mediterranean pasture grazed by free-ranging sheep and wild rabbits. We evaluate the effects of grazing on total root mass and vertical root distribution (0-4, 4-8 and 8-12 cm depths) in two neighboring topographic sites (uplands and lowlands) with different productivity using a replicated fence experiment which excludes sheep and sheep plus rabbits. We found evidences that grazing affected root biomass and vertical distribution at lowlands (high productivity habitats), where places grazed by sheep plus rabbits exhibit more root mass and a higher concentration of it towards the soil surface than only rabbits and ungrazed places. In contrast, grazing did not affect root biomass and vertical distribution at uplands (low productivity habitats). We suggest that higher nitrogen and organic matter found in lowlands permit a plant adjustment for nitrogen acquisition by increasing biomass allocation to root production which would allow plant regrowth and the quick completion of the annual life cycle. Contrary, soil resources scarcity at uplands do not permit plants modify their root growth patterns in response to grazing. Our study emphasizes the importance of primary productivity in predicting grazing effect on belowground processes in Mediterranean environments dominated by annuals.

Rueda, Marta; Rebollo, Salvador; Rodríguez, Miguel Á.

2010-07-01

41

Systems engineering overview for regenerative life-support systems applicable to space habitats  

NASA Technical Reports Server (NTRS)

The Life-Support Systems Group of the 1977 NASA Ames Summer Study conducted analyses initially to identify areas where partial or complete closure of the life-support system, for various types of space habitats, should be considered, and to develop a sound methodology for identifying, screening, and evaluating alternative closure schemes. Results of these analyses, including the systems engineering considerations that affect technology-development planning and management for regenerative life-support systems, are discussed. A recommended methodology is also presented as a basis for future technology-development activities in this area.

Spurlock, J.; Modell, M.

1979-01-01

42

Influence of habitat on behavior of Towndsend's ground squirrels (Spermophilus townsendii)  

USGS Publications Warehouse

Trade-offs between foraging and predator avoidance may affect an animal's survival and reproduction. These trade-offs may be influenced by differences in vegetative cover, especially if foraging profitability and predation risk differ among habitats. We examined above-ground activity of Townsend's ground squirrels (Spermophilus townsendii) in four habitats in the Snake River Birds of Prey National Conservation Area in southwestern Idaho to determine if behavior of ground squirrels varied among habitats, and we assessed factors that might affect perceived predation risk (i. e. predator detectability, predation pressure, population density). The proportion of time spent in vigilance by ground squirrels in winterfat (Krascheninnikovia lanata) and mosaic habitats of winterfat-sagebrush (Artemisia tridentata) was more than twice that of ground squirrels in burned and unburned sagebrush habitats. We found no evidence for the 'many-eyes' hypothesis as an explanation for differences in vigilance among habitats. Instead, environmental heterogeneity, especially vegetation structure, likely influenced activity budgets of ground squirrels. Differences in vigilance may have been caused by differences in predator detectability and refuge availability, because ground squirrels in the winterfat and mosaic habitats also spent more time in upright vigilant postures than ground squirrels in burned-sagebrush or sagebrush habitats. Such postures may enhance predator detection in low-growing winterfat.

Sharpe, Peter B.; Van Horne, Beatrice

1998-01-01

43

Food Web Stability: The Influence of Trophic Flows across Habitats  

Microsoft Academic Search

In nature, fluxes across habitats often bring both nu- ory, which plays a central role in consumer-resource in- trient and energetic resources into areas of low productivity from areas of higher productivity. These inputs can alter consumption teractions and food web dynamics. They further rates of consumer and predator species in the recipient food webs, suggested that multichannel omnivory can

Kevin McCann

1998-01-01

44

Habitat and distribution of post-recruit life stages of the squid Loligo forbesii  

NASA Astrophysics Data System (ADS)

This study models habitat preferences of the squid Loligo forbesii through its post-recruitment life cycle in waters around Scotland (UK). Trawl survey and market sample data from 1985 to 2004 are used to model seasonal habitats of immature, maturing and mature squid (maturity being inferred from size and season). Squid presence-absence and catch rate in areas of presence were analysed using generalised additive models, relating spatiotemporal patterns of distribution and abundance to ecogeographic variables. For all maturity classes, higher abundance in winter and spring (i.e., quarters 1 and 2) was associated with deeper water while higher abundance in summer and autumn (quarters 3 and 4) was associated with shallower water, consistent with seasonal onshore-offshore migrations but suggesting that most spawning may take place in deeper waters. The preferred SST range was generally 8-8.75 °C while preferred salinity values were below 35‰ in winter and summer and above 35‰ in spring and autumn. Squid were positively associated with gravel substrate and negatively associated with mud. Seasonal changes in habitat use were more clearly evident than changes related to inferred maturity, although the two effects cannot be fully separated due to the annual life cycle. Habitat selection for this species can be satisfactorily modelled on a seasonal basis; predictions based on such models could be useful for fishers to target the species more effectively, and could assist managers wishing to protect spawning grounds. The extent to which this approach may be useful for other cephalopods is discussed.

Smith, Jennifer M.; Macleod, Colin D.; Valavanis, Vasilis; Hastie, Lee; Valinassab, Tooraj; Bailey, Nick; Santos, M. Begoña; Pierce, Graham J.

2013-10-01

45

Modeling and simulation of an aquatic habitat for bioregenerative life support research  

NASA Astrophysics Data System (ADS)

Long duration human spaceflight poses challenges for spacecraft autonomy and the regeneration of life support consumables, such as oxygen and water. Bioregenerative life support systems (BLSS), which make use of biological processes to transform biological byproducts back into consumables, have the ability to recycle organic byproducts and are the preferred option for food production. A limitation in BLSS research is in the non-availability of small-scale experimental capacities that may help to better understand the challenges in system closure, integration, and control. Ground-based aquatic habitats are an option for small-scale research relevant to bioregenerative life support systems (BLSS), given that they can operate as self-contained systems enclosing a habitat composed of various species in a single volume of water. The purpose of this paper is to present the modeling and simulation of a reconfigurable aquatic habitat for experiments in regenerative life support automation; it supports the use of aquatic habitats as a small-scale approach to experiments relevant to larger-scale regenerative life support systems. It presents ground-based aquatic habitats as an option for small-scale BLSS research focusing on the process of respiration, and elaborates on the description of biological processes by introducing models of ecophysiological phenomena for consumers and producers: higher plants of the species Bacopa monnieri produce O2 for snails of the genus Pomacea; the snails consume O2 and generate CO2, which is used by the plants in combination with radiant energy to generate O2 through the process of photosynthesis. Feedback controllers are designed to regulate the concentration of dissolved oxygen in the water. This paper expands the description of biological processes by introducing models of ecophysiological phenomena of the organisms involved. The model of the plants includes a description of the rate of CO2 assimilation as a function of irradiance. Simulations and validation runs with hardware show how these phenomena may act as disturbances to the control mechanisms that maintain safe concentration levels of dissolved oxygen in the habitat.

Drayer, Gregorio E.; Howard, Ayanna M.

2014-01-01

46

Shifting the life-history paradigm: discovery of novel habitat use by hawksbill turtles.  

PubMed

Adult hawksbill turtles (Eretmochelys imbricata) are typically described as open-coast, coral reef and hard substrate dwellers. Here, we report new satellite tracking data on female hawksbills from several countries in the eastern Pacific that revealed previously undocumented behaviour for adults of the species. In contrast to patterns of habitat use exhibited by their Caribbean and Indo-Pacific counterparts, eastern Pacific hawksbills generally occupied inshore estuaries, wherein they had strong associations with mangrove saltwater forests. The use of inshore habitats and affinities with mangrove saltwater forests presents a previously unknown life-history paradigm for adult hawksbill turtles and suggests a potentially unique evolutionary trajectory for the species. Our findings highlight the variability in life-history strategies that marine turtles and other wide-ranging marine wildlife may exhibit among ocean regions, and the importance of understanding such disparities from an ecological and management perspective. PMID:21880620

Gaos, Alexander R; Lewison, Rebecca L; Yañez, Ingrid L; Wallace, Bryan P; Liles, Michael J; Nichols, Wallace J; Baquero, Andres; Hasbún, Carlos R; Vasquez, Mauricio; Urteaga, José; Seminoff, Jeffrey A

2012-02-23

47

Shifting the life-history paradigm: discovery of novel habitat use by hawksbill turtles  

PubMed Central

Adult hawksbill turtles (Eretmochelys imbricata) are typically described as open-coast, coral reef and hard substrate dwellers. Here, we report new satellite tracking data on female hawksbills from several countries in the eastern Pacific that revealed previously undocumented behaviour for adults of the species. In contrast to patterns of habitat use exhibited by their Caribbean and Indo-Pacific counterparts, eastern Pacific hawksbills generally occupied inshore estuaries, wherein they had strong associations with mangrove saltwater forests. The use of inshore habitats and affinities with mangrove saltwater forests presents a previously unknown life-history paradigm for adult hawksbill turtles and suggests a potentially unique evolutionary trajectory for the species. Our findings highlight the variability in life-history strategies that marine turtles and other wide-ranging marine wildlife may exhibit among ocean regions, and the importance of understanding such disparities from an ecological and management perspective. PMID:21880620

Gaos, Alexander R.; Lewison, Rebecca L.; Yanez, Ingrid L.; Wallace, Bryan P.; Liles, Michael J.; Nichols, Wallace J.; Baquero, Andres; Hasbun, Carlos R.; Vasquez, Mauricio; Urteaga, Jose; Seminoff, Jeffrey A.

2012-01-01

48

Accessible habitat for shorebirds: Factors influencing its availability and conservation implications  

USGS Publications Warehouse

We examined the relationship between water levels and accessible habitat, and how accessible habitat influenced Dunlin (Calidris alpina) and Semipalmated Sandpiper (Calidris pusilla) numbers in managed wetlands at Pea Island (North Carolina) and Merritt Island (Florida) National Wildlife Refuges in 1998 and 1999. At Pea Island we experimentally manipulated water levels, which also allowed us to examine the effects of water level fluctuations on prey base. We examined these relationships because access to foraging habitat by shorebirds is positively related to the length of their tarsometatarsus, and in the southeastern United States, small calidrids are a numerically important component of the two million migrants using inland and managed wetlands. We confirmed the importance of shallow waters for Dunlin and Semipalmated Sandpiper-numbers increased with increasing availability of 0-4 cm habitat. At Merritt Island, Dunlin use was inversely related to variability in water depth of 0-4 cm. Minimizing the frequency and amplitude of water level fluctuations associated with single-capped culverts is necessary to improve habitat quality. After adjusting for accessibility, spring habitat requirements for Dunlin and Semipalmated Sandpiper at Pea Island were met under nearly all abundance scenarios. We identified water level targets that maximize accessible habitat at Pea Island. In contrast, winter habitat requirements for Dunlin at Merritt Island were not met except in one scenario. Seasonally low prey density contributed to the shortfall, suggesting that allocating more habitat is the primary management option. Manipulating water levels at Pea Island did not adversely affect the density of eight shorebird prey species. Estimates of accessible habitat and other parameters (e.g., turnover rates, prey biomass) are essential to set and implement realistic shorebird habitat conservation goals.

Collazo, J.A.; O'Harra, D. A.; Kelly, C.A.

2002-01-01

49

Vacant Habitats in the Universe  

NASA Astrophysics Data System (ADS)

The search for life on other planets usually makes the assumption that where there is a habitat, it will contain life. On the present-day Earth, uninhabited habitats (or vacant habitats) are rare, but might occur, for example, in subsurface oils or impact craters that have been thermally sterilized in the past. Beyond Earth, vacant habitats might similarly exist on inhabited planets or on uninhabited planets, for example on a habitable planet where life never originated. The hypothesis that vacant habitats are abundant in the Universe is testable by studying other planets. In this review, I discuss how the study of vacant habitats might ultimately inform an understanding of how life has influenced geochemical conditions on Earth.

Cockell, Charles S.

2010-12-01

50

Vacant habitats in the Universe.  

PubMed

The search for life on other planets usually makes the assumption that where there is a habitat, it will contain life. On the present-day Earth, uninhabited habitats (or vacant habitats) are rare, but might occur, for example, in subsurface oils or impact craters that have been thermally sterilized in the past. Beyond Earth, vacant habitats might similarly exist on inhabited planets or on uninhabited planets, for example on a habitable planet where life never originated. The hypothesis that vacant habitats are abundant in the Universe is testable by studying other planets. In this review, I discuss how the study of vacant habitats might ultimately inform an understanding of how life has influenced geochemical conditions on Earth. PMID:21146249

Cockell, Charles S

2011-02-01

51

Influence of landscape elements on population densities and habitat use of three small-mammal species.  

SciTech Connect

Mabry, K.E., E.A. Dreelin, and G.W. Barrett. 2003. Influence of landscape elements on population densities and habitat use of three small-mammal species. J. Mammology. 84(1):20-25. Corridor effects on population densities and habitat use of 3 small mammal species were assessed in an experimentally fragmented landscape. Corridor presence did not have a statistically significant effect on population densities of cotton rats or cotton mice; however, a significant effect was observed for old-field mice. The results suggest that landscape fragmentation and habitat structure may have varying effects on population densities of different species.

Mabry, Karen, E.; Dreelin, Erin, A.; Barrett, Gary, W.

2003-01-01

52

Influences of fluctuating flows on spawning habitat and recruitment success  

NASA Astrophysics Data System (ADS)

Over the 50 years of daily peak power generation, no ramping restrictions, and loss of gravel due to operations of Philpott Dam, on Smith River, has created a wider, rectangular-shaped channel, with steeper banks. The pattern caused by channel degradation, tributary headcutting, bank erosion, and downstream aggradation has limited the length of productive habitat to between 3 and 10 river kilometers from the dam. Here the channel appears to contain key habitats where we found the highest redd densities, abundance, and spawner biomass for brown trout (Salmo trutta). Recruitment of brown trout to the fishable size classes is constrained by the daily hydropower peaking operations. The number of young brown trout produced each year was strongly related to the average magnitude of the peak flow and the duration of generation flows. Magnitude of peak flows also depressed abundance of native fishes. Although, brown trout actively removed fine sediment via redd construction and spawning, thereby increasing gravel permeability, the fine sediments from tributaries and bank erosion rapidly intruded into the spawning gravel in downstream reaches of the river. We recommend mitigating the effects of fluctuating releases from Philpott Dam through a combination of flow management and habitat improvement.

Orth, D. J.; Krause, C. W.; Novinger, D. C.

2005-05-01

53

Does rock disturbance by superb lyrebirds (Menura novaehollandiae) influence habitat selection by juvenile snakes?  

Microsoft Academic Search

Ver tebrates that destroy or disturb habitats used by other animals may influence habitat selection by sympatric taxa. In south-east Australian forests, superb lyrebirds (Menura novaehollandiae) displace soil, leaf litter and rocks during their daily foraging activities. We investigated whether superb lyrebirds disturb small sandstone rocks that endangered broad-headed snakes Hoplocephalus bungaroides and common small-eyed snakes Cryptophis nigrescens use as

JONATHAN K. WEBB; MARTIN J. WHITING

2006-01-01

54

Toward an Identification of Resources Influencing Habitat Use in a Multi-Specific Context  

PubMed Central

Interactions between animal behaviour and the environment are both shaping observed habitat use. Despite the importance of inter-specific interactions on the habitat use performed by individuals, most previous analyses have focused on case studies of single species. By focusing on two sympatric populations of large herbivores with contrasting body size, we went one step beyond by studying variation in home range size and identifying the factors involved in such variation, to define how habitat features such as resource heterogeneity, resource quality, and openness created by hurricane or forest managers, and constraints may influence habitat use at the individual level. We found a large variability among individual's home range size in both species, particularly in summer. Season appeared as the most important factor accounting for observed variation in home range size. Regarding habitat features, we found that (i) the proportion of area damaged by the hurricane was the only habitat component that inversely influenced roe deer home range size, (ii) this habitat type also influenced both diurnal and nocturnal red deer home range sizes, (iii) home range size of red deer during the day was inversely influenced by the biomass of their preferred plants, as were both diurnal and nocturnal core areas of the red deer home range, and (iv) we do not find any effect of resource heterogeneity on home range size in any case. Our results suggest that a particular habitat type (i.e. areas damaged by hurricane) can be used by individuals of sympatric species because it brings both protected and dietary resources. Thus, it is necessary to maintain the openness of these areas and to keep animal density quite low as observed in these hunted populations to limit competition between these sympatric populations of herbivores. PMID:22216164

Richard, Emmanuelle; Said, Sonia; Hamann, Jean-Luc; Gaillard, Jean-Michel

2011-01-01

55

The influence of habitat provisioning: use of earthworm burrows by the terrestrial salamander, Plethodon cinereus  

Microsoft Academic Search

Studies examining the influence of habitat provisioning by one species on the behavior of other species can provide key insights\\u000a regarding impacts of ecosystem engineers on the availability of resources to other species. More specifically, an organism’s\\u000a use of additional habitat provided by ecosystem engineers may affect the interpretation of observational or demographic data.\\u000a We chose to examine the possible

Rita I. Cáceres-Charneco; Tami S. Ransom

2010-01-01

56

Influence of Mowing Artemisia tridentata ssp. wyomingensis on Winter Habitat for Wildlife  

Microsoft Academic Search

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production\\u000a for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter\\u000a habitat for wildlife is lacking. This information is crucial because many wildlife species depended on

Kirk W. Davies; Jonathan D. Bates; Dustin D. Johnson; Aleta M. Nafus

2009-01-01

57

Evaluating the Influence of Geomorphic Conditions on Instream Fish Habitat Using Hydraulic Modeling and Geostatistical Analyses  

NASA Astrophysics Data System (ADS)

A two-dimensional hydrodynamic model (River2D) was utilized to evaluate the relationship between geomorphic conditions (as estimated using an existing rapid assessment protocol) and instream habitat quality in small Vermont streams. Six stream reaches ranging in geomorphic condition from good to poor according to the protocols were utilized for this study. We conducted detailed topographic surveys, quantified bed substrate, and measured velocity and discharge values during baseflow conditions. The reach models were calibrated with realistic roughness values based on field observations and pebble counts. After calibration, the weighted usable area (WUA) of habitat was calculated for each stream at three flows (7Q 10, median, and bankfull) using modeled parameters and habitat suitability curves for specific fish species and life stage. Brown trout (Salmo trutta), white sucker (Catostomus commersoni), and common shiner (Notropis cornutus) habitats were predicted using habitat parameters of velocity, depth, and channel substrate type for adult, juvenile, and fry stages. The predictions of reach-averaged WUA show a negative correlation to the geomorphic condition scores, indicating that the often-used rapid protocols, may not directly relate to habitat conditions at the reach spatial scale. However, the areas of high WUA are distributed in a patchy nature throughout the stream. This fluctuation of physical habitat conditions may be more important to classifying habitat than a single reach-averaged WUA score. The spatial distribution of habitat variables is not captured using either the reach-averaged WUA or geomorphic assessment scores to classify streams. Spatial analyses will be used to further evaluate the patchy nature of WUA distributions, and actual data on species distributions in the study streams will be compared to modeled habitat parameters and their spatial patterns.

Clark, J. S.; Rizzo, D. M.; Hession, W. C.; Watzin, M. C.; Laible, J. P.

2006-05-01

58

Short-Term Influence of Tank Tracks on Vegetation and Microphytic Crusts in Shrubsteppe Habitat  

PubMed

/ I examined vegetation and microphytic crust cover on two sites in burned and two sites in unburned big sagebrush (Artemisia tridentata Nutt.) habitat within the Idaho Army National Guard Orchard Training Area in southwestern Idaho. The purpose of this study was to determine the short-term (1-2 years) influence of tank tracks on vegetation and microphytic crusts in shrubsteppe habitat. The two types of tank tracks studied were divots (area where one track has been stopped or slowed to make a sharp turn) and straight-line tracks. Divots generally had a stronger influence on vegetation and microphytic crusts than did straight-line tracks. Tank tracks increased cover of bare ground, litter, and exotic annuals, and reduced cover of vegetation, perennial native grasses, sagebrush, and microphytic crusts. Increased bare ground and reduced cover of vegetation and microphytic crusts caused by tank tracks increase the potential for soil erosion and may reduce ecosystem productivity. Reduced sagebrush cover caused by tank tracks may reduce habitat quality for rodents. Tank tracks may also facilitate the invasion of exotic annuals into sagebrush habitat, increasing the potential for wildfire and subsequent habitat degradation. Thus, creation of divots and movement through sagebrush habitat by tanks should be minimized.KEY WORDS: Divots; Fire history; Idaho; Military; Sagebrush; Straight-line tracks PMID:9582396

Watts

1998-07-01

59

Breeding in high-elevation habitat results in shift to slower life-history strategy within a single species.  

PubMed

1. Elevational gradients create environmental variation that is hypothesized to promote variation in life-history strategies. We tested whether differences in life-history strategies were associated with elevation in a songbird, the dark-eyed junco (Junco hyemalis; Aves; A.O.U. 1998). 2. We monitored birds in four replicated sites per elevation, at 2000 m a.s.l. (high elevation) and 1000 m a.s.l. (low elevation), in the Rocky Mountains of Canada. 3. Over 5 years, we measured the following traits and vital rates: egg-laying schedules, morphological indicators of reproductive stage, seasonal reproductive success, indicators of competitive class (age, size, arrival time), and survival rates. 4. We found two main patterns: with an increase in breeding elevation, dark-eyed juncos delayed the development of structures necessary for reproduction (e.g. cloacal protuberance in males) and reduced the duration of their reproductive period to less than half of the time used by low-elevation birds; and 5. Juncos at high-elevation sites had 55-61% lower annual reproductive success and 15 to 20% higher survival rates. While adult juncos at high elevations produced fewer offspring, those offspring were in better condition. Proportions of age and size classes in high- compared to low-elevation populations were similar, suggesting that a life-history trade-off is present, rather than competition forcing inferior competitors to breed in a peripheral habitat. The apparent trade-off between reproduction and survival corresponded to a shorter period of favourable weather and available food in high- compared to low-elevation habitats. 6. Thus, elevation had a strong influence on life-history characteristics of a single species over a short spatial distance, suggesting a shift in life history from a high reproductive strategy at lower elevations to a high survivor strategy at high elevations. 7. This is the first paper to show a shift in avian life-history strategies along an elevational gradient (in both genders, of multiple age classes) when region (latitude) and phylogenetic histories are controlled for. PMID:19007385

Bears, H; Martin, K; White, G C

2009-03-01

60

ESTIMATING GRIZZLY BEAR DISTRIBUTION AND ABUNDANCE RELATIVE TO HABITAT AND HUMAN INFLUENCE  

Microsoft Academic Search

Understanding factors that influence and predict grizzly bear (Ursus arctos) distribution and abundance is fundamental to their conservation. In southeast British Columbia, Canada, we applied DNA hair-trap sampling (1) to evaluate relationships of grizzly bear detections with landscape variables of habitat and human activity, and (2) to model the spatial distribution and abundance of grizzly bears. During 1996-1998, we sampled

CLAYTON D. APPS; BRUCE N. McLELLAN; JOHN G. WOODS; MICHAEL F. PROCTOR; Gehrt

2004-01-01

61

INFLUENCE OF FRESHWATER INPUT ON THE HABITAT VALUE OF OYSTER REEFS IN THREE SOUTHWEST FLORIDA ESTUARIES.  

EPA Science Inventory

In order to examine the influence of freshwater input on the habitat value of oyster reefs, a spatiotemporal comparison of reef-resident fishes and decapod crustaceans was conducted during three seasonally dry and three seasonally wet months in three Southwest Florida estuaries: ...

62

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. PMID:21529251

Perez-Guerrero, Sergio; Redondo, Alberto Jose; Yela, Jose Luis

2011-01-01

63

TOPP AS A MARINE LIFE OBSERVATORY: USING ELECTRONIC TAGS TO MONITOR THE MOVEMENTS, BEHAVIOUR AND HABITATS OF MARINE VERTEBRATES  

Microsoft Academic Search

The Tagging of Pacific Pelagic (TOPP) a field program of the Census of Marine Life has proven the concept of using electronic tags to develop a Marine Life Observatory (MLO) to monitor the habitat utilization, movement patterns and behaviour of large marine predators. Given the difficulty of observing the behavior of highly pelagic marine species we know relatively little about

64

Habitat of early life: Solar X-ray and UV radiation at Earth's surface 43.5 billion years ago  

E-print Network

here, including the effects of flares and activity cycles, using a solar-like star that has the sameHabitat of early life: Solar X-ray and UV radiation at Earth's surface 4­3.5 billion years ago of the circumstances under which life formed on Earth. The quantity that is received depends on two main variables

Utrecht, Universiteit

65

Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2009  

SciTech Connect

This report describes the 2009 research conducted under the U.S. Army Corps of Engineers (USACE or Corps) project EST-09-P-01, titled “Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary.” The research was conducted by the Pacific Northwest National Laboratory, Marine Science Laboratory and Hydrology Group, in partnership with the University of Washington, School of Aquatic and Fishery Sciences, Columbia Basin Research, and Earl Dawley (NOAA Fisheries, retired). This Columbia River Fish Mitigation Program project, referred to as “Salmonid Benefits,” was started in FY 2009 to evaluate the state-of-the science regarding the ability to quantify the benefits to listed salmonids1 of habitat restoration actions in the lower Columbia River and estuary.

Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, John R.; Dawley, Earl M.; Coleman, Andre M.

2010-08-01

66

Research planning criteria for regenerative life-support systems applicable to space habitats  

NASA Technical Reports Server (NTRS)

The second phase of analyses that were conducted by the Life Support Systems Group of the 1977 NASA Ames Summer Study is described. This phase of analyses included a preliminary review of relevant areas of technology that can contribute to the development of closed life-support systems for space habitats, the identification of research options in these areas of technology, and the development of guidelines for an effective research program. The areas of technology that were studied included: (1) nutrition, diet, and food processing; (2) higher plant agriculture; (3) animal agriculture; (4) waste conversion and resource recovery; and (5) system stability and safety. Results of these analyses, including recommended research options and criteria for establishing research priorities among these many options, are discussed.

Spurlock, J.; Cooper, W.; Deal, P.; Harlan, A.; Karel, M.; Modell, M.; Moe, P.; Phillips, J.; Putnam, D.; Quattrone, P.

1979-01-01

67

Joint Effects of Habitat Heterogeneity and Species' Life-History Traits on Population Dynamics in Spatially Structured Landscapes  

PubMed Central

Both habitat heterogeneity and species’ life-history traits play important roles in driving population dynamics, yet there is little scientific consensus around the combined effect of these two factors on populations in complex landscapes. Using a spatially explicit agent-based model, we explored how interactions between habitat spatial structure (defined here as the scale of spatial autocorrelation in habitat quality) and species life-history strategies (defined here by species environmental tolerance and movement capacity) affect population dynamics in spatially heterogeneous landscapes. We compared the responses of four hypothetical species with different life-history traits to four landscape scenarios differing in the scale of spatial autocorrelation in habitat quality. The results showed that the population size of all hypothetical species exhibited a substantial increase as the scale of spatial autocorrelation in habitat quality increased, yet the pattern of population increase was shaped by species’ movement capacity. The increasing scale of spatial autocorrelation in habitat quality promoted the resource share of individuals, but had little effect on the mean mortality rate of individuals. Species’ movement capacity also determined the proportion of individuals in high-quality cells as well as the proportion of individuals experiencing competition in response to increased spatial autocorrelation in habitat quality. Positive correlations between the resource share of individuals and the proportion of individuals experiencing competition indicate that large-scale spatial autocorrelation in habitat quality may mask the density-dependent effect on populations through increasing the resource share of individuals, especially for species with low mobility. These findings suggest that low-mobility species may be more sensitive to habitat spatial heterogeneity in spatially structured landscapes. In addition, localized movement in combination with spatial autocorrelation may increase the population size, despite increased density effects. PMID:25232739

Ye, Xinping; Skidmore, Andrew K.; Wang, Tiejun

2014-01-01

68

Life course influences on quality of life in early old age  

Microsoft Academic Search

A growing literature demonstrates life course influences on health in early old age. The present paper is the first to examine whether similar processes also influence quality of life in early old age. The question is theorised in terms of structured dependency and third age, and the life course pathways by which people arrive at these destinations in later life.

D. Blane; P. Higgs; M. Hyde; R. D. Wiggins

2004-01-01

69

Multiple stressors and complex life cycles: insights from a population-level assessment of breeding site contamination and terrestrial habitat loss in an amphibian.  

PubMed

Understanding the effects of chemical contaminants on natural populations is challenging, as multiple anthropogenic and natural stressors may individually and interactively influence responses. Population models can be used to evaluate the impacts of multiple stressors and to provide insight into population-level effects and/or data gaps. For amphibians with complex life cycles, population models may be useful in understanding impacts of stressors that are unique to the habitat type (aquatic, terrestrial) and that operate at different times in the life cycle. We investigated the population-level effects of aquatic contaminants (coal combustion residues, CCR) and terrestrial habitat loss on the eastern narrowmouth toad, Gastrophryne carolinensis, using existing empirical data that demonstrated negative reproductive and developmental effects of CCR and a series of population models that incorporated density dependence and environmental stochasticity. Results of deterministic models indicated that when terrestrial habitat was abundant, CCR-exposed toads had a larger population size compared to the reference population as a result of reduced density-dependent effects on larval survival. However, when stochasticity in the form of catastrophic reproductive failure was included, CCR-exposed toads were more susceptible to decline and extinction compared to toads from the reference populations. The results highlight the complexities involved in assessing the effects of anthropogenic factors on natural populations, especially for species that are exposed to multiple biotic and abiotic stressors during different periods in the life cycle. PMID:21922532

Salice, Christopher J; Rowe, Christopher L; Pechmann, Joseph H K; Hopkins, William A

2011-12-01

70

Stable isotope ratios indicate that body condition in migrating passerines is influenced by winter habitat.  

PubMed Central

Although predicted some time ago, there has been little success in demonstrating that the overall fitness of migratory birds depends on the combined influences of their experiences over all seasons. We used stable carbon isotope signatures (delta13C) in the claws of migrating black-throated blue warblers Dendroica caerulescens to infer their wintering habitats and investigated whether winter habitat selection can be linked to condition during migration. Resident bird species with low delta13C corresponded to selection of more mesic habitats, and migrating birds with low delta13C were in better condition than conspecifics with higher delta13C signatures. These findings concur with empirical observations on the wintering grounds, where dominants (mostly males) tend to exclude subordinates from mesic areas (considered to be high-quality habitats). We believe that variation in condition during migration may be one of the key factors determining differences in arrival times and condition at the breeding areas, which in turn have a major influence on reproductive success. PMID:15252988

Bearhop, Stuart; Hilton, Geoff M; Votier, Stephen C; Waldron, Susan

2004-01-01

71

Virtual Habitat -a dynamic simulation of closed life support systems -human model status  

NASA Astrophysics Data System (ADS)

In order to optimize Life Support Systems on a system level, stability questions must be in-vestigated. To do so the exploration group of the Technical University of Munich (TUM) is developing the "Virtual Habitat" (V-HAB) dynamic LSS simulation software. V-HAB shall provide the possibility to conduct dynamic simulations of entire mission scenarios for any given LSS configuration. The Virtual Habitat simulation tool consists of four main modules: • Closed Environment Module (CEM) -monitoring of compounds in a closed environment • Crew Module (CM) -dynamic human simulation • P/C Systems Module (PCSM) -dynamic P/C subsystems • Plant Module (PM) -dynamic plant simulation The core module of the simulation is the dynamic and environment sensitive human module. Introduced in its basic version in 2008, the human module has been significantly updated since, increasing its capabilities and maturity significantly. In this paper three newly added human model subsystems (thermal regulation, digestion and schedule controller) are introduced touching also on the human stress subsystem which is cur-rently under development. Upon the introduction of these new subsystems, the integration of these into the overall V-HAB human model is discussed, highlighting the impact on the most important I/F. The overall human model capabilities shall further be summarized and presented based on meaningful test cases. In addition to the presentation of the results, the correlation strategy for the Virtual Habitat human model shall be introduced assessing the models current confidence level and giving an outlook on the future correlation strategy. Last but not least, the remaining V-HAB mod-ules shall be introduced shortly showing how the human model is integrated into the overall simulation.

Markus Czupalla, M. Sc.; Zhukov, Anton; Hwang, Su-Au; Schnaitmann, Jonas

72

Mangrove habitat partitioning by Ucides cordatus (Ucididae): effects of the degree of tidal flooding and tree-species composition during its life cycle  

NASA Astrophysics Data System (ADS)

Environmental factors strongly affect mangrove crabs, and some factors modulate population structure and habitat partitioning during the crabs' life cycle. However, the effect of these environmental factors on habitat selection by mangrove crabs is still unknown. We evaluated habitat selection by the mangrove crab Ucides cordatus in mangrove forests with different degrees of predominance of Rhizophora mangle, Laguncularia racemosa or Avicennia schaueriana, two tidal flooding levels (less- and more-flooded), and two biological periods (breeding and non-breeding seasons). Sampling was conducted in four mangrove forests with different influences of these biotic and abiotic parameters. We used the data for sex ratio to explain environmental partitioning by this species. Females predominated in R. mangle mangroves, independently of the biological period (breeding or non-breeding seasons), and males predominated only in the less-flooded L. racemosa mangroves. The flooding level affected the sex ratio of U. cordatus, with a predominance of males in less-flooded mangroves, independently of the biological period; and a gender balance in the more-flooded mangroves only during the breeding season. Outside the breeding season, the largest specimens were recorded in the R. mangle mangroves, but in the breeding season, the largest crabs were recorded in the L. racemosa mangroves with a higher level of flooding. These results suggest that tree-species composition and tidal flooding level can have a significant effect on the habitat partitioning of sexes and sizes of the mangrove crab U. cordatus both during and outside the breeding season.

Wunderlich, A. C.; Pinheiro, M. A. A.

2013-06-01

73

Cross-generational effects of habitat and density on life history in red deer.  

PubMed

We used long-term data on movements, survival, and reproduction of female red deer (Cervus elaphus Linnaeus) of the Isle of Rum, Scotland (1970-2001), to explain variation in life history (age at maturity) from a hind's access to habitat resources and exposure to local density, and cross-generational (maternal) effects on observed relationships. We described each hind's use of resources relative to availability in the study area from an individual-based resource selection function (RSF); we defined local density as the total number of hinds aged > or = 1 year within the subpopulation cluster to which an individual belonged. The likelihood of a hind producing her first calf in the period from birth to the end of the summer in which she turned age 3 was positively related to relative use of Agrostis/Festuca grasslands and other low-elevation communities, and inversely related to a hind's mean annual local density. However, when we considered both a daughter's RSF and exposure to local density and her mother's RSF and exposure to local density, maternal data alone most parsimoniously explained variation in age at maturity of daughters. Mothers were able to lower age at maturity in their daughters in two, non-mutually exclusive ways. First, birth mass of daughters was inversely related to age at maturity, and mothers that used relatively less uplands (Calluna-dominated heath and heather moorland) and occupied areas of lower density produced larger offspring. Second, mothers could establish a home range that enabled daughters to mature in areas with access to high quality Agrostis/Festuca grasslands at low density. Lifetime reproductive success was inversely associated with a hind's age at maturity via extension of the reproductive life span. Longevity did not change in association with age at maturity. Patterns in how animals use available habitat resources may depend on that of previous generations, especially at larger scales of resource selection. PMID:19137939

McLoughlin, Philip D; Coulson, Tim; Clutton-Brock, Tim

2008-12-01

74

Communication breakdown? Habitat influences on black-capped chickadee dawn choruses  

Microsoft Academic Search

The dawn chorus of the black-capped chickadee (Poecile atricapillus) is a communication network that functions in the dissemination of essential information for both males and females. Habitat\\u000a type may influence the performance of this network, and if recognized, chickadees may attempt to behaviorally compensate for\\u000a detrimental changes in the form of increased movement. We studied the dawn chorus of 66

Ingebjørg Jean K. Hansen; Ken A. Otter; Harry van Oort; Carmen I. Holschuh

2005-01-01

75

The influence of anthropogenic resources on multi-scale habitat selection by raccoons  

Microsoft Academic Search

With the continuing spread of urban areas, gaining a greater understanding of the effect of human presence on wildlife species\\u000a is essential for wildlife managers. We determined the influence of anthropogenic resources on home range size and habitat\\u000a selection of raccoons (Procyon lotor) during summer (June–August) 1996–2000 for 120 raccoons at three sites exposed to varying levels of urbanization and

Clare K. Bozek; Suzanne Prange; Stanley D. Gehrt

2007-01-01

76

The Influence of Dissolved Oxygen on Winter Habitat Selection by Largemouth Bass: An Integration of Field Biotelemetry Studies  

E-print Network

143 The Influence of Dissolved Oxygen on Winter Habitat Selection by Largemouth Bass with habitat availability to assess whether fish were selecting for spe- cific dissolved oxygen concentrations largemouth bass acclimated to winter tem- peratures. Results from the dissolved oxygen measurements made

Cooke, Steven J.

77

Factors influencing abundance of butterflies and burnet moths in the uncultivated habitats of an organic farm in Denmark  

Microsoft Academic Search

Biotic and abiotic factors causing aggregations of butterflies were investigated in a variety of uncultivated habitats on an organic farm in Denmark. By combining the method of butterfly transect counting with multiple regression analysis, environmental and floral variables influencing butterfly abundance in linear and non-linear uncultivated habitats were identified. Dependent variables were: butterfly totals, Thymelicus spp. (mainly T. lineola), Aphantopus

H. D. Clausen; J. Reddersen

2001-01-01

78

Influence of Habitat Modifications on Habitat Composition and Anadromous Salmonid Populations in Fish Creek, Oregon, 1983-1988 Annual Report.  

SciTech Connect

Modification of degraded habitats to increase populations of anadromous salmonids is a major focus of management agencies throughout the Pacific Northwest. Millions of dollars are spent annually on such efforts. Inherent in implementing habitat improvements is the need for quantitative evaluation of the biological and physical effects of such work. Reeves et al. (in press), however, noted that such evaluations are rare, making it difficult to assess the true results of habitat work. While it is not economically possible to thoroughly evaluate every habitat project, it is essential that intensive evaluations be done on selected representative projects. One such evaluation program has been underway since 1982 on Fish Creek, a tributary of the Clackamas River near Estacada, OR. Habitat modification has been done by the USDA Forest Service, Estacada Ranger District, Mt. Hood National Forest with funding provided in part by the Bonneville Power Administration (BPA). The USDA Forest Service, Anadromous Fish Habitat Research Unit, Pacific Northwest Research Station (PNW), Corvallis, OR is charged with: (1) evaluating the biological and physical responses to habitat modifications on a basin scale; and (2) developing a cost-benefit analysis of the program. Preliminary results have been reported in a series of annual publications, Everest and Sedell 1983, 1984 and Everest et al. 1985, 1986, 1987, 1988. The objectives of this paper are to: (1) report 1988 observations of biological and physical changes in habitat, salmonid populations, and smolt production in Fish Creek, and (2) examine preliminary trends in fish habitat and populations related to habitat improvement over the period 1983-1988. We have prefaced the trends in the latter objective as preliminary because we believe it could take a minimum of 10 years before the full biological and physical responses to habitat work are realized. We therefore urge caution in interpreting these preliminary results.

Reeves, Gordon H.; Everest, Fred H. (Oregon State University, Pacific Northwest Forest and Range Experiment Station, Corvallis, OR); Hohler, David B. (Mount Hood National Forest, Clackamas River Ranger District, Estacada, OR)

1990-05-01

79

Abiotic vs. biotic influences on habitat selection of coexisting species: Climate change impacts?  

USGS Publications Warehouse

Species are commonly segregated along gradients of microclimate and vegetation. I explore the question of whether segregation is the result of microhabitat partitioning (biotic effects) or choice of differing microclimates (abiotic effects). I explored this question for four ground-nesting bird species that are segregated along a microclimate and vegetation gradient in Arizona. Birds shifted position of their nests on the microhabitat and microclimate gradient in response to changing precipitation over nine years. Similarly, annual bird abundance varied with precipitation across 12 yr. Those shifts in abundance and nesting microhabitat with changing precipitation demonstrate the importance of abiotic influences on bird distributions and habitat choice. However, nest-site shifts and microhabitat use also appear to be influenced by interactions among coexisting species. Moreover, shifts in habitat use by all species caused nest predation (i.e., biotic) costs that increased with increasing distance along the microclimate gradient. These results indicate that abiotic and biotic costs can strongly interact to influence microhabitat choice and abundances of coexisting species. Global climate change impacts have been considered largely in terms of simple distributional shifts, but these results indicate that shifts can also increase biotic costs when species move into habitat types for which they are poorly adapted or that create new biotic interactions.

Martin, T. E.

2001-01-01

80

Analysis of the Influence of Spatial Pattern in Habitat Selection Studies  

USGS Publications Warehouse

Design and analysis of wildlife habitat selection studies typically do not assess the effect of spatial pattern on the habitat selection process. Effects of landscape scale pattern on habitat selection cannot be accomplished without replicate study areas, because pattern is a single, albeit multifaceted, attribute of an area. For a single area, however, the influence of pattern-related characteristics, such as shape and edge shared with adjacent patches, can be estimated by using GLIM (McCullough and Neider 1983) procedures to model patch-specific frequency counts of animal use as a function of these parameters. This approach is evaluated and illustrated with simulated breeding-bird counts in a South Carolina study area for which a GIS land cover classification is available. A related technique for evaluating whether movement from patch to patch is selective is developed and illustrated for designs that involve collection of trajectory data from monitored individuals. These designs and analyses are feasible given current GIS and GPS technology. Statistical inferences from habitat selection studies should be interpreted within the context of a range of scales at which animals differentiate between patch attributes.

Otis, D.L.

1998-01-01

81

Life history and habitat use of the speckled worm eel, Myrophis punctatus, along the east coast of the United States  

Microsoft Academic Search

Many species of fishes along the east coast of the United States have complex life histories, especially those that move over\\u000a hundreds of kilometers across ocean and estuarine habitats. To further unravel the life history of one of these, the speckled\\u000a worm eel, Myrophis punctatus we examined samples from extensive time series and discrete samples collected in the ocean and

Kenneth W. Able; Dennis M. Allen; Gretchen Bath-Martin; Jonathan A. Hare; Donald E. Hoss; Katrin E. Marancik; Perce M. Powles; David E. Richardson; J. Christopher Taylor; Harvey J. Walsh; Charles Wenner

82

Dynamics of antibacterial activity in three species of Caribbean marine algae as a function of habitat and life history  

Microsoft Academic Search

Antibacterial activity of lipid extracts from three species of Caribbean marine algae, Spyridia filamentosa, S. hypnoides and Wrangelia bicuspidata was evaluated monthly for one year. Activities were tested for whole plant extracts and TLC-separable zones. Whole plant extracts demonstrated monthly variability in activity with respect to both habitat and life history phase in addition to periods of similarity. No consistency

Pedro O. Robles-Centeno; David L. Ballantine; William H. Gerwick

1996-01-01

83

Biological and ecological traits of Trichoptera: the influence of phylogeny on life history and behavioral traits  

NASA Astrophysics Data System (ADS)

Biological and ecological traits of fauna have the potential to indicate changes in community structure that relate to function as an alternative to using traditional taxonomic descriptors. However, traits may be inherited, and consequently, not all species traits are independent of phylogeny. When used in analyses of community structure, results based on traits may be difficult to interpret; suites of traits may respond together even if only one trait is responding to changes in the habitat. To determine the relationship between traits and phylogeny, we examined life history and behavioral traits for the extant 45 families of Trichoptera. Traits such as larval size, respiratory strategies, case or net materials, locomotion, food and functional feeding group, voltanism, diapause, habitat, and reproduction were collected from published life histories. Traits were then coded and mapped onto the phylogeny of Trichoptera to determine the correlations between traits, as well as correlations directly influenced by the phylogeny. Traits such as functional feeding group, reproductive strategies, and building materials were correlated with phylogeny, while traits such as locomotion and habitat type were less influenced by phylogeny. Consideration of macroinvertebrate phylogenies when selecting biological and ecological traits may be essential for accurate interpretation of community function.

Mendez, P. K.; Resh, V. H.

2005-05-01

84

The influence of fine-scale habitat features on regional variation in population performance of alpine White-tailed Ptarmigan  

USGS Publications Warehouse

It is often assumed (explicitly or implicitly) that animals select habitat features to maximize fitness. However, there is often a mismatch between preferred habitats and indices of individual and population measures of performance. We examined the influence of fine-scale habitat selection on the overall population performance of the White-tailed Ptarmigan (Lagopus leucura), an alpine specialist, in two subdivided populations whose habitat patches are configured differently. The central region of Vancouver Island, Canada, has more continuous and larger habitat patches than the southern region. In 2003 and 2004, using paired logistic regression between used (n = 176) and available (n = 324) sites, we identified food availability, distance to standing water, and predator cover as preferred habitat components . We then quantified variation in population performance in the two regions in terms of sex ratio, age structure (n = 182 adults and yearlings), and reproductive success (n = 98 females) on the basis of 8 years of data (1995-1999, 2002-2004). Region strongly influenced females' breeding success, which, unsuccessful hens included, was consistently higher in the central region (n = 77 females) of the island than in the south (n = 21 females, P = 0.01). The central region also had a much higher proportion of successful hens (87%) than did the south (55%, P < 0.001). In light of our findings, we suggest that population performance is influenced by a combination of fine-scale habitat features and coarse-scale habitat configuration. ?? The Cooper Ornithological Society 2011.

Fedy, B.; Martin, K.

2011-01-01

85

Effect of habitat preference on frond life span in three Cyathea tree ferns  

NASA Astrophysics Data System (ADS)

It has been reported that plants living in various geographical areas had different physiological forms, as factors of microenvironment have strong impacts on physiological characters. However, the physiological characters of fronds have been scarcely reported in ferns. In this study, we investigated physiological differences in response to the habitat preference in the three tree ferns in northeast Taiwan, Cyathea lepifera, C. spinulosa, and C. podophylla, prefer to open site, edge of forest, and interior forest, respectively. The canopy openness above the individuals of C. lepifera, C. spinulosa and C. podophylla were 29.2 ± 14.10 , 7.0 ± 3.07 and 5.0 ± 2.24 %, respectively. Among three species, C. podophylla had the longest frond life span (13.0 ± 4.12 months) than the two others (C. lepifera (6.8 ± 1.29 months) and C. spinulosa (7.3 ±1.35 months). Our result supported the general patterns that shade intolerant species have a shorter leaf life span than shade tolerant species. The maximum net CO2 assimilation of C. lepifera, C. spinulosa and C. podophylla were 11.46 ± 1.34, 8.27 ± 0.69, and 6.34 ± 0.54 ?mol CO2 m-2 s-1, respectively. As well, C. lepifera had the highest photosynthetic light saturation point (LSP), while C. podophylla had the lowest LSP among these three tree ferns. These suggested that C. lepifera could be more efficient for capturing and utilizing light resources under the larger canopy openness condition than the other two species. We also found that frond C : N ratio were positively correlated with frond life span among species. C. podophylla, with the longest frond life span, had the highest frond C : N ratio (22.17 ± 1.95), which was followed by C. spinulosa (18.58 ± 1.37) and C. lepifera (18.68 ± 2.63) with shorter frond life span. The results were consistent to the theory that the fronds and leaves of shade intolerant species have high photosynthetic abilities with low C : N ratio. Key words: Canopy openness, frond life span, tree fern, Cyathea, frond C : N ratio

Chiu, Tzu Yun; Wang, Hsiang Hua; Lun Kuo, Yao; Kume, Tomonori

2013-04-01

86

Testing the risk of predation hypothesis: the influence of recolonizing wolves on habitat use by moose.  

PubMed

Considered as absent throughout Scandinavia for >100 years, wolves (Canis lupus) have recently naturally recolonized south-central Sweden. This recolonization has provided an opportunity to study behavioral responses of moose (Alces alces) to wolves. We used satellite telemetry locations from collared moose and wolves to determine whether moose habitat use was affected by predation risk based on wolf use distributions. Moose habitat use was influenced by reproductive status and time of day and showed a different selection pattern between winter and summer, but there was weak evidence that moose habitat use depended on predation risk. The seemingly weak response may have several underlying explanations that are not mutually exclusive from the long term absence of non-human predation pressure: intensive harvest by humans during the last century is more important than wolf predation as an influence on moose behavior; moose have not adapted to recolonizing wolves; and responses may include other behavioral adaptations or occur at finer temporal and spatial levels than investigated. PMID:25015119

Nicholson, Kerry L; Milleret, Cyril; Månsson, Johan; Sand, Håkan

2014-09-01

87

Virtual Habitat -a Dynamic Simulation of Closed Life Support Systems -Overall Status and Outlook  

NASA Astrophysics Data System (ADS)

In order to optimize Life Support Systems (LSS) on a system level, stability questions and closure grade must be investigated. To do so the exploration group of the Technical University of Munich (TUM) is developing the "Virtual Habitat" (V-HAB) dynamic LSS simulation software. The main advantages of the dynamic simulation of LSS within V-HAB are the possibilities to compose different LSS configurations from the LSS subsystems and conduct dynamic simulation of it to test its stability in different mission scenarios inclusive emergency events and define the closure grade of the LSS. Additional the optimization of LSS based on different criteria will be possible. The Virtual Habitat simulation tool consists of four main modules: • Closed Environment Module (CEM) -monitoring of compounds in a closed environment • Crew Module (CM) -dynamic human simulation • P/C Systems Module (PCSM) -dynamic P/C subsystems • Plant Module (PM) -dynamic plant simulation Since the first idea and version, the V-HAB simulation has been significantly updated increasing its capabilities and maturity significantly. The updates which shall be introduced concern all modules of V-HAB. In particular: Significant progress has been made in development of the human model. In addition to the exist-ing human sub-models three newly developed ones (thermal regulation, digestion and schedule controller) have been introduced and shall be presented. Regarding the Plant Module a wheat plant model has been integrated in the V-HAB and is being correlated against test data. Ad-ditionally a first version of the algae bioreactor model has been developed and integrated. In terms of the P/C System module, an innovative approach for the P/C subsystem modelling has been developed and applied. The capabilities and features of the improved V-HAB models and the overall functionality of the V-HAB are demonstrated in form of meaningful test cases. In addition to the presentation of the results, the correlation strategy for the Virtual Habitat simulation shall be introduced assessing the models current confidence level and giving an outlook on the future correlation strategy.

Zhukov, Anton; Schnaitmann, Jonas; Mecsaci, Ahmad; Bickel, Thomas; Markus Czupalla, M. Sc.

88

Elk migration patterns and human activity influence wolf habitat use in the Greater Yellowstone Ecosystem  

USGS Publications Warehouse

Identifying the ecological dynamics underlying human–wildlife conflicts is important for the management and conservation of wildlife populations. In landscapes still occupied by large carnivores, many ungulate prey species migrate seasonally, yet little empirical research has explored the relationship between carnivore distribution and ungulate migration strategy. In this study, we evaluate the influence of elk (Cervus elaphus) distribution and other landscape features on wolf (Canis lupus) habitat use in an area of chronic wolf–livestock conflict in the Greater Yellowstone Ecosystem, USA. Using three years of fine-scale wolf (n = 14) and elk (n = 81) movement data, we compared the seasonal habitat use of wolves in an area dominated by migratory elk with that of wolves in an adjacent area dominated by resident elk. Most migratory elk vacate the associated winter wolf territories each summer via a 40–60 km migration, whereas resident elk remain accessible to wolves year-round. We used a generalized linear model to compare the relative probability of wolf use as a function of GIS-based habitat covariates in the migratory and resident elk areas. Although wolves in both areas used elk-rich habitat all year, elk density in summer had a weaker influence on the habitat use of wolves in the migratory elk area than the resident elk area. Wolves employed a number of alternative strategies to cope with the departure of migratory elk. Wolves in the two areas also differed in their disposition toward roads. In winter, wolves in the migratory elk area used habitat close to roads, while wolves in the resident elk area avoided roads. In summer, wolves in the migratory elk area were indifferent to roads, while wolves in resident elk areas strongly avoided roads, presumably due to the location of dens and summering elk combined with different traffic levels. Study results can help wildlife managers to anticipate the movements and establishment of wolf packs as they expand into areas with migratory or resident prey populations, varying levels of human activity, and front-country rangelands with potential for conflicts with livestock.

Nelson, Abigail; Kauffman, Matthew J.; Middleton, Arthur D.; Jimenez, Mike; McWhirter, Douglas; Barber, Jarrett; Gerow, Ken

2012-01-01

89

Behavioral adjustments of African herbivores to predation risk by lions: spatiotemporal variations influence habitat use.  

PubMed

Predators may influence their prey populations not only through direct lethal effects, but also through indirect behavioral changes. Here, we combined spatiotemporal fine-scale data from GPS radio collars on lions with habitat use information on 11 African herbivores in Hwange National Park (Zimbabwe) to test whether the risk of predation by lions influenced the distribution of herbivores in the landscape. Effects of long-term risk of predation (likelihood of lion presence calculated over four months) and short-term risk of predation (actual presence of lions in the vicinity in the preceding 24 hours) were contrasted. The long-term risk of predation by lions appeared to influence the distributions of all browsers across the landscape, but not of grazers. This result strongly suggests that browsers and grazers, which face different ecological constraints, are influenced at different spatial and temporal scales in the variation of the risk of predation by lions. The results also show that all herbivores tend to use more open habitats preferentially when lions are in their vicinity, probably an effective anti-predator behavior against such an ambush predator. Behaviorally induced effects of lions may therefore contribute significantly to structuring African herbivore communities, and hence possibly their effects on savanna ecosystems. PMID:19294909

Valeix, M; Loveridge, A J; Chamaillé-Jammes, S; Davidson, Z; Murindagomo, F; Fritz, H; Macdonald, D W

2009-01-01

90

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. PMID:23818967

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

2013-01-01

91

Modeling habitat split: landscape and life history traits determine amphibian extinction thresholds.  

PubMed

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. PMID:23818967

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

2013-01-01

92

Indigenous Microbiota and Habitat Influence Escherichia coli Survival More than Sunlight in Simulated Aquatic Environments  

PubMed Central

The reported fate of Escherichia coli in the environment ranges from extended persistence to rapid decline. Incomplete understanding of factors that influence survival hinders risk assessment and modeling of the fate of fecal indicator bacteria (FIB) and pathogens. FIB persistence in subtropical aquatic environments was explored in outdoor mesocosms inoculated with five E. coli strains. The manipulated environmental factors were (i) presence or absence of indigenous microbiota (attained by natural, disinfected, and cycloheximide treatments), (ii) freshwater versus seawater, and (iii) water column versus sediment matrices. When indigenous microbes were removed (disinfected), E. coli concentrations decreased little despite exposure to sunlight. Conversely, under conditions that included the indigenous microbiota (natural), significantly greater declines in E. coli occurred regardless of the habitat. The presence of indigenous microbiota and matrix significantly influenced E. coli decline, but their relative importance differed in freshwater versus seawater. Cycloheximide, which inhibits protein synthesis in eukaryotes, significantly diminished the magnitude of E. coli decline in water but not in sediments. The inactivation of protozoa and bacterial competitors (disinfected) caused a greater decline in E. coli than cycloheximide alone in water and sediments. These results indicate that the autochthonous microbiota are an important contributor to the decline of E. coli in fresh and seawater subtropical systems, but their relative contribution is habitat dependent. This work advances our understanding of how interactions with autochthonous microbiota influence the fate of E. coli in aquatic environments and provides the framework for studies of the ecology of enteric pathogens and other allochthonous bacteria in similar environments. PMID:23811514

Korajkic, Asja; Wanjugi, Pauline

2013-01-01

93

Habitat Restrictions in Early Benthic Life: Experiments on Habitat Selection and In situ Predation with the American Lobster.  

National Technical Information Service (NTIS)

In shallow marine environments, many animals that eventually attain large body size and range widely are restricted to refugia early in life. A prime example is the American lobster Homarus americanus Milne Edwards. During the first few years of benthic l...

R. A. Wahle, R. S. Steneck

1992-01-01

94

Influence of mowing Artemisia tridentata ssp. wyomingensis on winter habitat for wildlife.  

PubMed

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter habitat for wildlife is lacking. This information is crucial because many wildlife species depended on A. tridentata spp. wyomingensis plant communities for winter habitat and consume significant quantities of Artemisia during this time. Furthermore, information is generally limited describing the recovery of A. tridentata spp. wyomingensis to mowing and the impacts of mowing on stand structure. Stand characteristics and Artemisia leaf tissue crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were measured in midwinter on 0-, 2-, 4-, and 6-year-old fall-applied mechanical (mowed at 20 cm height) treatments and compared to adjacent untreated (control) areas. Mowing compared to the control decreased Artemisia cover, density, canopy volume, canopy elliptical area, and height (P < 0.05), but all characteristics were recovering (P < 0.05). Mowing A. tridentata spp. wyomingensis plant communities slightly increases the nutritional quality of Artemisia leaves (P < 0.05), but it simultaneously results in up to 20 years of decrease in Artemisia structural characteristics. Because of the large reduction in A. tridentata spp. wyomingensis for potentially 20 years following mowing, mowing should not be applied in Artemisia facultative and obligate wildlife winter habitat. Considering the decline in A. tridentata spp. wyomingensis-dominated landscapes, we caution against mowing these communities. PMID:19159967

Davies, Kirk W; Bates, Jonathan D; Johnson, Dustin D; Nafus, Aleta M

2009-07-01

95

Influence of Mowing Artemisia tridentata ssp. wyomingensis on Winter Habitat for Wildlife  

NASA Astrophysics Data System (ADS)

Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter habitat for wildlife is lacking. This information is crucial because many wildlife species depended on A. tridentata spp. wyomingensis plant communities for winter habitat and consume significant quantities of Artemisia during this time . Furthermore, information is generally limited describing the recovery of A. tridentata spp. wyomingensis to mowing and the impacts of mowing on stand structure. Stand characteristics and Artemisia leaf tissue crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were measured in midwinter on 0-, 2-, 4-, and 6-year-old fall-applied mechanical (mowed at 20 cm height) treatments and compared to adjacent untreated (control) areas. Mowing compared to the control decreased Artemisia cover, density, canopy volume, canopy elliptical area, and height ( P < 0.05), but all characteristics were recovering ( P < 0.05). Mowing A. tridentata spp. wyomingensis plant communities slightly increases the nutritional quality of Artemisia leaves ( P < 0.05), but it simultaneously results in up to 20 years of decrease in Artemisia structural characteristics. Because of the large reduction in A. tridentata spp. wyomingensis for potentially 20 years following mowing, mowing should not be applied in Artemisia facultative and obligate wildlife winter habitat. Considering the decline in A. tridentata spp. wyomingensis-dominated landscapes, we caution against mowing these communities.

Davies, Kirk W.; Bates, Jonathan D.; Johnson, Dustin D.; Nafus, Aleta M.

2009-07-01

96

Habitat preferences and life history of the red scorpion fish, Scorpaena notata, in the Mediterranean  

NASA Astrophysics Data System (ADS)

Scorpaena notata is a small, sedentary scorpaenid species widely distributed in the Mediterranean and adjacent waters of the Atlantic. In the western Mediterranean it inhabits coastal continental shelf bottoms. In the Balearic Islands, these bottoms are characterised by the presence of the facies with red algae, including both Peyssonnelia and mäerl beds. These beds enhance the structural complexity, biodiversity and secondary production of the soft bottoms. Due to the oceanographic conditions of the Islands, the facies with red algae are especially rich in terms of biomass and algal coverage, and are widespread distributed between 40 and 90 m depth, where trawlers exploiting the continental shelf operate. The present work studies the biology of S. notata and its relationship with habitat characteristics. Special attention is focused on the aspects related to fish condition and growth as a tool to assess the importance of the facies with red algae for fish. The reproduction period of S. notata in the Balearic Islands occurs in summer and is accompanied by a decrease in hepatic condition, as it happens in the adjacent area off the Iberian Peninsula; however, in contrast with this adjacent area, this period is accompanied by a decrease in somatic condition and an increase in feeding potential, which suggests that these could be adaptations to the higher oligotrophy of the Archipelago. The standardised algal biomass (mostly Rhodophyceae) present in the bottoms positively affected the abundance, somatic condition and feeding potential of S. notata. Individuals inhabiting bottoms with the highest algal biomass showed faster growth than the entire population analysed together. Both, the structural complexity and the availability of preys in the facies with red algae are revealed as advantageous traits for the life history of fish. Taking into account the importance of individual health for the overall success of the population, the indexes studied here could be a useful tool for identifying high quality or essential fish habitats. Our results highlight the importance of the facies with red algae as oasis of high productivity where benthic fish can circumvent the general oligotrophic conditions of the Mediterranean, and the necessity of urgent management measures in order to protect them from human impacts.

Ordines, F.; Quetglas, A.; Massutí, E.; Moranta, J.

2009-12-01

97

Declining Lake Habitats in the Andes: Implications for Early Mars, Life, and Exploration (Invited)  

NASA Astrophysics Data System (ADS)

The environment of the Andes presents analogies with Mars when the planet was transitioning from a wetter to a drier, colder climate: thin atmosphere, high solar irradiance, depleted ozone, high temperature fluctuations with low averages, ice, low precipitation and RH, and volcanic activity. This region is also among three areas of the world most impacted by climate change, which results in enhanced evaporation and high negative water balance that modifies lake habitat rapidly. Data shows strong interannual fluctuations in precipitation, water balance, major ion concentration, and pH are well marked. Microorganisms dwelling near the surface are exposed to a UV flux 170% that of sea level, and exceptionally high UVB levels. The thin cold atmosphere generates sudden and significant inverse relationship between UV and temperatures. In this cold, unstable environment lake habitats host abundant life. In addition to adaptation strategies, the timing of key cycles appears to be a critical factor in life’ survival. Environmental analogy with early Mars is multifold. Aridification has resulted in an evaporative environment. Latitude and altitude generate a UV-flux double that of present-day Mars at the equator and UVB only half that of the red planet, low average total ozone, and a low atmospheric pressure. Yearly temperature extremes range from -40C to +9C. Lakes are ice-covered starting austral fall, reaching maximum thickness by mid-winter. Thawing occurs in spring, but negative night temperatures result in the formation of a thin film of ice that thaws by mid-morning in spring and summer. Because of their geophysical environment, rapid climate change, isolation, and mostly uncharted ecosystems, these lakes are representative of an end-member class of terrestrial lakes and are meaningful analogs to early martian lakes. With differences inherent to the study of terrestrial analogs, the overall environmental similarity of Andean lakes with Mars at the Noachian/Hesperian transition makes them uniquely similar to early martian lakes and a window into the likely transformation they experienced during the transition period from a wet to a dry Mars. Our results show that decline was unlikely to be monotonical over time on Mars, and therefore probably challenging for putative life, if any, to adapt to. Physicochemical changes associated with such variability are significant. There is currently no data to show how this environmental roller coaster impacts biodiversity at the level of the overall population’s density or that of the species. However, the relatively low diversity found in the samples of the microbial community is consistent with biodiversity loss and selection of specific species capable of mutating and adapting rapidly. The timing of key cycles appears critical to the ecosystem’s survival. Here, we will discuss our latest results, the main similarities and differences with Mars, and how exploring these analogs help us better learn how to identify their signatures on Mars.

Cabrol, N. A.; Grin, E. A.; High Lakes Project Team

2010-12-01

98

Plenty to eat, nothing to breathe: challenges to life in serpentinite habitats (Invited)  

NASA Astrophysics Data System (ADS)

When tectonic uplift exposes ultramafic rocks from the Earth's mantle to water from the surface, iron minerals are oxidized and release hydrogen gas (H2) in a set of geochemical reactions known collectively as serpentinization. The generation of high concentrations of H2 can also lead to abiotic synthesis of organic molecules, thereby providing an exothermic, abundant source of electron donors and organic carbon. The major biological challenges of serpentinization-influenced habitats appear to be the extremely high pH (typically pH 9-12), the associated lack of inorganic carbon, and the lack of electron acceptors due to the highly reducing conditions (1). These challenges are apparently overcome by the prolific archaeal and bacterial biofilms associated with the carbonate chimneys at the Lost City hydrothermal field. Cell densities exceed 109 cells per gram of chimney material (2). Phylogenetic, metagenomic, and experimental evidence indicate that the communities are supported by the copious quantities of H2, CH4, and sulphur fluxing from the chimneys, but the metabolic pathways and associated thermodynamic factors are still unclear (3). In particular, the oxidants that microbes couple with H2, CH4, and sulphur at Lost City remain a matter of speculation. The mystery of the oxidants has also featured in our recent explorations of continental sites of serpentinization. In strong contrast to the Lost City chimneys, these continental fluids tend to contain very little biomass (fewer than 102 cells per mL in the most extreme cases). Presumably, the anoxic, pH 12 fluids enriched in H2 and CH4 are flowing from subsurface habitats where there must be a surplus of reductants and carbon (4). Given the extremely reducing, anoxic conditions, though, oxidants are likely to be very limited in these environments. The ';oxidant limitation' hypothesis is particularly intriguing because of its counter-intuitive nature: to our knowledge, no other habitats on Earth have a surplus of reducants and a lack of oxidants. Other limitations must also be considered, including the extremely high pH and the possible lack of nitrogen, phosphorus, and trace metals. Comparisons of the bacterial communities at Lost City and continental serpentinite springs have highlighted the dynamic nature of the Lost City chimneys, where highly reducing hydrothermal fluids mix with oxidizing seawater (1,5). Consequently, a truly subsurface microbial community below Lost City remains to be detected and will require future sampling efforts to focus on the collection of high-quality, end-member hydrothermal fluids. References 1. Schrenk MO, Brazelton WJ, Lang SQ. 2013. Rev. Mineral. Geochem. 75:575-606. 2. Schrenk MO, Kelley DS, Bolton SA, Baross JA. 2004. Environ. Microbiol. 6:1086-1095. 3. Brazelton WJ, Mehta MP, Kelley DS, Baross JA. 2011. mBio2:4. doi:10.1128/mBio.00127-11. 4. Szponar, N., W.J. Brazelton, M.O. Schrenk, D.M. Bower, A. Steele, P.L. Morrill. 2013. Icarus. 224: 286-296. 5. Brazelton WJ, Schrenk MO, Kelley DS, Baross JA. 2006. Appl. Environ. Microbiol. 72:6257-6270.

Brazelton, W. J.; Twing, K. I.; Crespo-Medina, M.; Lang, S. Q.; Schrenk, M. O.

2013-12-01

99

Factors Influencing Adjustment to Late-Life Divorce.  

ERIC Educational Resources Information Center

Although the rate of divorce among older Americans has increased steadily, little attention has been paid to late life divorce. To describe the role of age and other factors which might influence adjustment to divorce in later life, data from a larger pilot study were used: 81 divorced persons over the age of 60 completed in-depth, structured…

Wilson, Keren Brown; DeShane, Michael R.

100

Endothermy in African platypleurine cicadas: the influence of body size and habitat (Hemiptera: Cicadidae).  

PubMed

The platypleurine cicadas have a wide distribution across Africa and southern Asia. We investigate endothermy as a thermoregulatory strategy in 11 South African species from five genera, 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 body temperature (T(b)) show that these animals regulate T(b) through endogenous heat production. Heat production in the laboratory elevated T(b) to the same range as in animals active in the field. Maximum T(b) measured during calling activity when there was no access to solar radiation ranged from 13.2 degrees to 22.3 degrees C above ambient temperature in the five species measured. The mean T(b) during activity without access to solar radiation did not differ from the mean T(b) during diurnal activity. All platypleurines exhibit a unique behavior for cicadas while warming endogenously, a temperature-dependent telescoping pulsation of the abdomen that probably functions in ventilation. Platypleurines generally call from trunks and branches within the canopy and appear to rely on endothermy even when the sun is available to elevate T(b), in contrast to the facultative endothermy exhibited by New World endothermic species. The two exceptions to this generalization we found within the platypleurines are Platypleura wahlbergi and Albanycada albigera, which were the smallest species studied. The small size of P. wahlbergi appears to have altered their thermoregulatory strategy to one of facultative endothermy, whereby they use the sun when it is available to facilitate increases in T(b). Albanycada albigera is the only ectothermic platypleurine we found. The habitat and host plant association of A. albigera appear to have influenced the choice of ectothermy as a thermoregulatory strategy, as the species possesses the metabolic machinery to elevate to the T(b) range observed in the endothermic species. Therefore, size and habitat appear to influence the expression of thermoregulatory strategies in African platypleurine cicadas. PMID:15547799

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

2004-01-01

101

Influence of habitat structure and resource availability on the movements of Rhagoletis indifferens (Diptera: Tephritidae).  

PubMed

Habitat structure and resources availability may differentially influence movement between habitat patches. We examined fly movement decisions (stay or leave) at the scale of individual trees by measuring the response of marked Rhagoletis indifferens (Diptera: Tephritidae) to sweet cherry trees (Prunus avium) that were manipulated by changing the shape of the tree (structure treatment = normal or reduced) and the fruit load (fruit treatment = augmented, normal, or reduced). More than 600 observations were made at two field sites that differed in the average inter-tree distance: Senger site, 10.1 +/- 4.5 m; Tuemp site, 29.0 +/- 19.3 m. At the Senger site, flies were resighted most often in the normal structure-augmented fruit trees. At the Tuemp site, however, there were fewer transfers between trees, unusual tree preferences, and significant treatment interaction terms. Using a first principles diffusion model of attraction and by varying fly perceptual range to limit tree choice, we generated unusual tree preferences based on differential attraction to individual trees. Our results suggest that manipulating tree attractiveness may be a viable pest management strategy for closely spaced trees but not for dispersed trees. Further study into the relationship between the spatial arrangement of trees and the flies' ability to detect specific tree characteristics is warranted. PMID:19508793

Senger, S E; Tyson, R; Roitberg, B D; Thistlewood, H M A; Harestad, A S; Chandler, M T

2009-06-01

102

Desiccation of Rock Pool Habitats and Its Influence on Population Persistence in a Daphnia Metacommunity  

PubMed Central

Habitat instability has an important influence on species' occurrence and community composition. For freshwater arthropods that occur in ephemeral rock pools, the most drastic habitat instabilities are droughts and the intermittent availability of water. However, although the desiccation of a rock pool is detrimental for planktonic populations, it may also bring certain benefits: the exclusion of predators or parasites, for example, or the coexistence of otherwise competitively exclusive species. The commonness of drought resistant resting stages in many aquatic organisms shows the ecological significance of droughts. We measured daily evaporation in 50 rock pools inhabited by three Daphnia species D. magna, D. longispina and D. pulex over one summer. Daily evaporation and ultimately desiccation showed significantly seasonally influenced correlation with pool surface area, presence of vegetation, ambient temperature, wind and standardized evaporation measures. We used the estimates from this analysis to develop a simulation model to predict changes in the water level in 530 individual pools on a daily basis over a 25-year period. Eventually, hydroperiod lengths and desiccation events could be predicted for all of these rock pools. We independently confirmed the validity of this simulation by surveying desiccation events in the 530 rock pools over a whole season in 2006. In the same 530 rock pools, Daphnia communities had been recorded over the 25 years the simulation model considered. We correlated pool-specific occupation lengths of the three species with pool-specific measures of desiccation risk. Occupation lengths of all three Daphnia species were positively correlated with maximum hydroperiod length and negatively correlated with the number of desiccation events. Surprisingly, these effects were not species-specific. PMID:19277113

Altermatt, Florian; Pajunen, V. Ilmari; Ebert, Dieter

2009-01-01

103

Influence of habitat modification on the intestinal helminth community ecology of cottontail rabbit populations.  

PubMed

The influence of five brush management treatments using the herbicides tebuthiuron and triclopyr, with or without prescribed burning, on the intestinal helminth community of cottontail rabbits (Sylvilagus floridanus) was studied in 1987 on the Cross Timbers Experimental Range in Payne County, Oklahoma (USA). Six helminth species were found (Dermatoxys veligera, Trichostrongylus calcaratus, Passalurus nonanulatus, Wellcomia longejector, Taenia pisiformis cystercercus, and Mosgovoyia pectinata americana) in 102 rabbits (88 adult and 14 juveniles) collected over two seasons (winter and summer). Prevalence of M. pectinata americana in cottontail rabbits was significantly greater in untreated control pastures than herbicide treated pastures in winter, while prevalence of T. pisiformis was significantly greater in burned than unburned pastures. Abundances of helminth species in the intestinal tract of cottontail rabbits were unaffected by brush treatments. Mosgovoyia pectinata americana abundance demonstrated a highly significant increase from winter to summer; conversely, abundance of all oxyurid pinworms combined (D. veligera, P. nonanulatus, W. longejector) was significantly higher in winter than summer. Helminth community dynamics were significantly influenced by season, but were unaffected by brush treatments. Habitat modification could have influenced cestode transmission by altering the ecology of invertebrate and vertebrate hosts. PMID:2338720

Boggs, J F; McMurry, S T; Leslie, D M; Engle, D M; Lochmiller, R L

1990-04-01

104

Can personality explain genetic influences on life events?  

PubMed

Previous research in the Swedish Adoption/Twin Study of Aging (SATSA) has found genetic influences on life events (R. Plomin, P. Lichtenstein, N.L. Pedersen, G.E. McClearn, & J.R. Nesselroade, 1990). The present study extends this finding by examining sex differences in genetic and environmental contributions to life events and by examining personality as a mediator of genetic influences on life events in SATSA. Analyses were based on 320 twin pairs, including identical and fraternal twins reared together and apart (mean age = 58.6 years). Controllable, desirable, and undesirable life events were revealed significant genetic variance for women. There was no significant genetic variance for either sex for uncontrollable events. Multivariate analyses of personality (as indexed by Neuroticism, Extraversion, and Openness to Experience) and life events suggest that all of the genetic variance on controllable, desirable, and undesirable life events for women is common to personality. Thus, in this sample of older adult women, genetic influences on life events appear to be entirely mediated by personality. PMID:9008381

Saudino, K J; Pedersen, N L; Lichtenstein, P; McClearn, G E; Plomin, R

1997-01-01

105

FEEDING HABITATS OF NESTING WADING BIRDS: SPATIAL USE AND SOCIAL INFLUENCES  

Microsoft Academic Search

In an effort to relate social interactions to feeding-habitat use, I observed six species of wading birds near a major colony site in coastal North Carolina. Three spatial scales of habitat use were considered: the general orientation to and from the colony (coarsest level), the habitat \\

R. MICHAEL ERWIN

106

Influence of habitat and landscape perenniality on insect natural enemies in three candidate biofuel crops  

Microsoft Academic Search

Cultivation of biofuel crops could change agricultural landscapes, affecting natural enemies at multiple scales. We sampled five natural enemy families with sticky cards in three model biofuel habitats (corn, switchgrass and prairie; n=60) across southern Michigan and Wisconsin, comparing captures between habitats and relating them to the area of forest, annual crop and herbaceous perennial habitat in the landscape within

Ben P. Werling; Timothy D. Meehan; Claudio Gratton; Douglas A. Landis

2011-01-01

107

Abstract Habitat loss and fragmentation can influ-ence the genetic structure of biological populations.  

E-print Network

Microsatellites Ã? Ursus americanus floridanus Introduction The fragmentation and loss of habitat is one consequences of habitat fragmentation and loss: the case of the Florida black bear (Ursus americanus floridanus populations. We studied the genetic consequences of habitat frag- mentation in Florida black bear (Ursus

Oli, Madan K.

108

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts  

PubMed Central

Background Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in these forest ecosystems and we therefore included nest site quality as an abiotic factor in the analysis. In contrast to previous studies based on local densities, we focus here on the positioning and spatial patterns and we use models to compare our predictions to random expectations. Results Colony demography was universally affected by the size of the nest site with larger and more productive colonies residing in larger nest sites of higher quality. Distance to the nearest competitor negatively influenced host demography and brood production in the Bavarian community, pointing to an important role of competition, while social parasitism was less influential in this community. The New York community was characterized by the highest habitat variability, and productive colonies were clustered in sites of higher quality. Colonies were clumped on finer spatial scales, when we considered only the nearest neighbors, but more regularly distributed on coarser scales. The analysis of spatial positioning within plots often produced different results compared to those based on colony densities. For example, while host and slavemaker densities are often positively correlated, slavemakers do not nest closer to potential host colonies than expected by random. Conclusions The three communities are differently affected by biotic and abiotic factors. Some of the differences can be attributed to habitat differences and some to differences between the two slavemaking-host ecosystems. The strong effect of competition in the Bavarian community points to the scarcity of resources in this uniform habitat compared to the other more diverse sites. The decrease in colony aggregation with scale indicates fine-scale resource hotspots: colonies are locally aggregated in small groups. Our study demonstrates that species relationships vary across scales and spatial patterns can provide important insights into species interactions. These results could not have been obtained with analyses based on local densities alone. Previous studies focused on social parasitism and its effect on host colonies. The broader approach taken here, considering several possible factors affecting colony demography and not testing each one in isolation, shows that competition and environmental variability can have a similar strong impact on demography and life-history of hosts. We conclude that the effects of parasites or predators should be studied in parallel to other ecological influences. PMID:21443778

2011-01-01

109

Influence of soil fauna and habitat patchiness on plant ( Betula pendula ) growth and carbon dynamics in a microcosm experiment  

Microsoft Academic Search

We tested (1) how the presence of a diverse soil faunal community affects ecosystem carbon balance and (2) whether habitat patchiness modifies the influence of soil fauna on plant growth and carbon dynamics. We constructed cylindrical microcosms that contained coniferous forest humus and different litter materials either mixed or in separate patches, and in the presence or absence of diverse

Pekka Sulkava; Veikko Huhta; Jouni Laakso; Eeva-Riitta Gylén

2001-01-01

110

The influence of research scale on bald eagle habitat selection along the lower Hudson River, New York (USA)  

Microsoft Academic Search

As the concepts of landscape ecology have been incorporated into other disciplines, the influence of spatial pat- terns on animal abundance and distribution has attracted considerable attention. However, there remains a sig- nificant gap in the application of landscape ecology theories and techniques to wildlife research. By combining landscape ecology techniques with traditional wildlife habitat analysis methods, we defined an

Craig M. Thompson; Kevin McGarigal

2002-01-01

111

Comparing Ecological Site Descriptions to Habitat Characteristics Influencing Greater Sage-Grouse Nest Site Occurrence and Success  

E-print Network

Comparing Ecological Site Descriptions to Habitat Characteristics Influencing Greater Sage-Grouse 82071, USA. Abstract We used 119 greater sage-grouse (Centrocercus urophasianus) nests located in predicting sage-grouse nest site occurrence and success as a univariate explanatory variable? 2) Can ESD

Beck, Jeffrey L.

112

Density of red alder ( Alnus rubra ) in headwaters influences invertebrate and detritus subsidies to downstream fish habitats in Alaska  

Microsoft Academic Search

We investigated the influence of red alder (Alnus rubra) stand density in upland, riparian forests on invertebrate and detritus transport from fishless headwater streams to downstream, salmonid habitats in southeastern Alaska. Red alder commonly regenerates after soil disturbance (such as from natural landsliding or timber harvesting), and is common along streams in varying densities, but its effect on food delivery

Mark S. Wipfli; Jake Musslewhite

2004-01-01

113

Influence of habitat complexity on route learning among different populations of climbing perch (Anabas testudineus Bloch, 1792)  

Microsoft Academic Search

Animals use different behavioral strategies to maximize their fitness in the natural environment. Learning and memory are critical in this context, allowing organisms to flexibly and rapidly respond to environmental changes. We studied how the physical characteristics of the native habitat influence the spatial learning capacity of Anabas testudineus belonging to four different populations collected from two streams and two

K. K. Sheenaja; K. John Thomas

2011-01-01

114

Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon. Annual Report 1996.  

SciTech Connect

This study is part of a multi-year research project studying aspects of bull trout life history, ecology and genetics. This report covers the activities of the project in 1996. Results and analysis are presented in the following five areas: (1) analysis of the genetic structure of Oregon bull trout populations; (2) distribution and habitat use of bull trout and brook trout in streams containing both species; (3) bull trout spawning surveys; (4) summary and analysis of historical juvenile bull trout downstream migrant trap catches in the Grande Ronde basin; and (5) food habits and feeding behavior of bull trout alone and in sympatry with brook trout.

Bellerud, Blane L.; Gunckel, Stephanie; Hemmingsen, Alan R.; Buchanan, David V.; Howell, Philip J.

1997-10-01

115

The influence of local habitat and landscape composition on cavity-nesting birds in a forested mosaic  

Microsoft Academic Search

Forest management influences both stand and landscape structure. While research exists on stand-scale habitat relationships for cavity-nesting birds, there are few studies at the landscape scale. In a managed forest, we characterised the influence of local vegetation on the occurrence of cavity-nesting bird species and determined whether landscape scale variables explained any of the remaining variation. We selected three spatial

Tara L. Warren; Matthew G. Betts; Antony W. Diamond; Graham J. Forbes

2005-01-01

116

Habitat Associations, Life History and Diet of the Sabine Shiner Notropis sabinae  

E-print Network

east Texas streams from November 2001 through October 2002. Notropis sabinae exhibited no strong. Temporal patterns in ovarian development, gonadosomatic index and ova development indicated that N. sabinae additional information is available about temporal trends in habitat associations and population age

Aspbury, Andrea S. - Department of Biology, Texas State University

117

Reproductive phenology, life-forms, and habitats of the Venezuelan Central Plain  

Microsoft Academic Search

percentage of species with unripe fruits produced throughout the year was more seasonal for the disturbed area than for the other habitats. Mature fruit patterns showed an increase during the late rainy season for the ecotone and savanna. A large number of herbaceous (annual and perennial) and liana species flowered during the wet season, and a smaller fraction flowered during

NELSON RAMIREZ; Facultad Ciencias

2002-01-01

118

Influence of habitat structure and nature of substratum on limpet recruitment: Conservation implications for endangered species  

NASA Astrophysics Data System (ADS)

Habitat complexity has been recognised to exert a significant influence on the abundance and diversity of benthic invertebrates. This issue is especially important for the management of endangered species. The recruitment of limpet species was monitored monthly for one year on natural and artificial surfaces. Control plots showed the highest mean number of species and individuals settled per plot, followed by rough then smooth plots. Control plots presented the highest mean diversity values followed by rough and smooth plots. Recruits of the endangered limpet Patella ferruginea were mainly observed during the spring, from April to June. Recruitment seemed to be influenced by both the heterogeneity and nature of the substratum. P. ferruginea repopulation programmes involving the translocation of recruits on experimental plates should be conducted using similar materials to the natural substratum, such as granite or limestone, rather than plastic, avoiding surfaces with low levels of heterogeneity, and taking into account that translocation of adults is not feasible due to the high mortality observed.

Espinosa, Free; Rivera-Ingraham, Georgina; García-Gómez, Jose C.

2011-08-01

119

Deep Reaching Gas-permeable Tectonic Faults of the Early Earth as Habitats for the Origin of Life  

NASA Astrophysics Data System (ADS)

The discussion on the origin of life encounters difficulties when it comes to estimate the conditions of the early earth and to define plausible environments for the development of the first complex organic molecules. Until now, the role of the earth's crust has been more or less ignored. First continental crustal cores may have been developed some tens to hundreds of million years after formation of earth. Due to tectonic stress the proto continents were sheared by vertical strike-slip faults at an early stage. These deep-reaching open, interconnected tectonic faults may provide possible reaction habitats ranging from nano- to centimetre and even larger dimensions that sum up to several cubic kilometres for the formation of prebiotic molecules. Their fillings consist of supercritical and subcritical waters and supercritical and subcritical gases. Here, all necessary raw materials including phosphate for the development of prebiotic molecules exist in variable concentrations and in sufficient quantities. Furthermore, there are periodically changing pressure and temperature conditions, varying pH-values, metallic surfaces, clay minerals and a large number of catalysts. While cosmic and UV-radiation are excluded, nuclear radiation intervenes the chemical evolution of the molecules inside the crust. Carbon dioxide (CO2) is of crucial importance. It can be present in an almost pure form as a supercritical fluid (scCO2) in a crustal depth less than 1 km (critical point of pure CO2: 74 bar; 31°C). Inside strike-slip faults, a two-phase system formed by supercritical CO2 in liquid water provides the environment for condensation and polymerisation of hydrogen cyanide, nucleobases, nucleotides and amino acids. ScCO2 is a non-polar solvent that is widely used in "green chemistry" (Anastas and Kirchhoff 2002) and enables the dissolution of non-polar reactants and their reactions normally occurring in the absence of water. Under the influence of periodically changing conditions (extreme earth tides played an important role for cyclic variations within the fluid-water-interface and for the development of gradients), the reaction products can be transferred into a neighbouring aqueous environment. Based on these conditions, prebiotic molecules could have been condensed to long-chained molecules, from which first cell structures could have been formed by chemical evolution. This hypothetical model for the origin of life can be used to design crucial experiments for the model's verification. Because all proposed processes could still occur in tectonic faults at the present time, it may be possible to detect and analyse the formation of prebiotic molecules in order to assess the validity of the proposed hypothesis. A clear indication of the geological provenience of corresponding organic substances arises, if these substances appear in racemic mixtures (e.g. d- and l-alanin), making them distinguishable from similar molecules of biological origin. Additionally, their isotopic composition can help to exclude a possible biological origin. Further on, the possible detection of these substances in fluid inclusions of quartz dykes of former deep crustal parts is another possible proof of the hypothesis. Keywords: origin, life, strike-slip faults, scCO2, prebiotic molecules

Schreiber, U.; Mayer, C.

2012-04-01

120

Context matters: matrix vegetation influences native and exotic species composition on habitat islands.  

PubMed

The extensive research on plant communities of natural-habitat islands has primarily focused on the "islands." The island analogy, however, potentially limits understanding of processes influencing composition on habitat islands because the nature of their matrix is overlooked. We determine how plant community structure of the surrounding matrix influences vegetation on volcanic outcrops in the modified landscape of Banks Peninsula, New Zealand. Our primary purpose is to address whether the matrix is more important for recently established exotic species than it is for well-established native species and whether such invasion by exotics has led to homogenization of the outcrop flora. To test this, we examined our data at three spatial scales: that of the entire outcrop flora, between individual outcrops and their immediate surrounding matrix, and between individual outcrop faces and the individual relevés of the immediate surrounding matrix. We found that 81% of the native flora and 90% of the exotic flora also occur in the matrix. This high level of species shared between the outcrop and matrix persists at the scale of individual outcrop faces (68% of the total flora of individual faces is shared with the matrix). We predicted that floras from different outcrops would vary in their distinctiveness from their immediate matrix. We found Bray-Curtis distance coefficient values to range from 0.26 to 0.64; these were even higher at the outcrop-face scale. Variability in outcrop distinctiveness relates primarily to the outcrop face properties of area, vegetation height, and soil depth, and matrix properties of vegetation structure and vegetation heterogeneity. The effect of the vegetation structure of the matrix is more pronounced on the exotic than on the native outcrop flora. The component of composition and structure of the matrix that was independent of outcrop properties and local environment accounts for similar levels of explainable variation in total and native composition (29-31%), but considerably more (40%) in composition of exotic species. Our results support our prediction that, as the surrounding matrix becomes more modified, invasion by exotics makes outcrop vegetation less distinct from its matrix. PMID:18409428

Wiser, Susan K; Buxton, Rowan P

2008-02-01

121

Psychosocial influences on blood pressure during daily life  

Microsoft Academic Search

Ambulatory blood pressure (ABP) monitoring allows frequent non-invasive blood pressure (BP) recordings in a variety of settings. Emerging evidence suggests that ABP is a better predictor of cardiovascular morbidity than clinic BP. Ambulatory blood pressure is influenced by a variety of physical, psychological and behavioral factors that comprise an individual's daily life. The present article reviews psychosocial research relating ABP

Robert A Carels; Andrew Sherwood; James A Blumenthal

1998-01-01

122

The influence of hydrogeomorphic dynamics on fish habitat: A case study using the ooCAESAR landscape evolution model  

NASA Astrophysics Data System (ADS)

The sediments, morphological features and riverflows that define the hydrogeomorphology of natural river channels provide physical habitat diversity that sustains the aquatic biodiversity of river ecosystems. This simple concept underpins the large number of contemporary ecohydraulic models that are available in the literature. Such models have been widely used to predict how morphological diversity (taken here to encompass channel sediments, topography and flow velocity) influences habitat quality for target species at the reach scale. The accuracy of these predictions is a matter of considerable practical importance, as the results are frequently used as the basis for restoration or rehabilitation. However, such models are limited in that they do not account for dynamic changes in river morphology, which themselves are triggered by changes in the flows of water and sediment delivered from the watershed upstream and stimulated by climatic, tectonic or land cover perturbations across a wide range of temporal scales. Accordingly there is an urgent need to combine the outputs of catchment-based geomorphological models with ecohydraulic models, so that predictions of habitat quality focused on specific reaches can be placed into their appropriate (i.e., the watershed) spatial context. To address these issues we herein present preliminary simulations from a case study of the Sulphur Creek watershed, a 24.2 sq. km., third-order catchment draining one of 47 tributaries to the Napa River, which empties southerly into the San Francisco Bay of northern California. Therein, the influence of catchment-scale geomorphic dynamics on reach-scale fish habitat is investigated using the ooCAESAR landscape evolution model. This cellular automaton model, based on its predecessor CAESAR, was chosen because it can be run at spatial resolutions (1 to 5 m.) that are ecologically meaningful and at temporal resolutions that capture both individual event dynamics and long-term evolutionary history. Water depths, velocities and surface grain size distributions produced by the ooCAESAR simulations are used to model habitat suitability for spawning and rearing lifestages of Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) using traditional habitat suitability curves. To drive the simulations, scenarios were developed that express a combination of plausible future events and time series based on climate (rainfall), land use, restoration and seismic variants. A subset of an ensemble of scenario-driven simulations are used to illustrate how non-linear catchment-scale dynamics influence the quality of fish habitat expressed at the reach-scale, in sometimes non-intuitive ways. Sediment budgets derived from the simulations help segregate processes and explain how the delivery and storage of sediment within the catchment combine to change physical habitat in reaches utilized by fish.

Wheaton, J. M.; Sear, D. A.; Darby, S. E.; Booker, D. E.; Acreman, M.

2005-12-01

123

Food resources influence spatial ecology, habitat selection, and foraging behavior in an ambush-hunting snake (Viperidae: Bothrops asper): an experimental study.  

PubMed

Prey availability affects many aspects of predators' life history and is considered a primary factor influencing individuals' decisions regarding spatial ecology and behavior, but few experimental data are currently available. Snakes may represent ideal model organisms relative to other animal groups for addressing such resource dependency, due to a presumably more direct link between food resources and many aspects of behavior and natural history. We experimentally investigated the relationship between food intake and spatial behavior in a population of the snake Bothrops asper in a Costa Rican lowland rainforest. Six adult snakes were allowed to forage naturally while six were offered supplemental food in the field, with both groups monitored using radiotelemetry. Mean home range size did not differ between groups presumably due to small sample size, but supplementally fed snakes demonstrated altered patterns of macro- and microhabitat selection, shorter and less frequent movements, and increased mass acquisition. Fed snakes also devoted less time to foraging efforts, instead more frequently remaining inactive and utilizing shelter. Because snakes were always fed in situ and not at designated feeding stations, observed shifts in habitat selection are not explained by animals simply moving to areas of higher food availability. Rather, B. asper may have moved to swamps in order to feed on amphibians when necessary, but remained in preferred forest habitat when food was otherwise abundant. The strong behavioral and spatiotemporal responses of snakes in this population may have been influenced by an overall scarcity of mammalian prey during the study period. PMID:22440190

Wasko, Dennis K; Sasa, Mahmood

2012-06-01

124

Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 2001.  

SciTech Connect

Bull trout Salvelinus confluentus exhibit a number of life history strategies. Stream-resident bull trout complete their life cycle in their natal tributaries. Migratory bull trout spawn in tributary streams where juvenile fish usually spend from one to four years before migrating to either a larger river (fluvial) or lake (adfluvial) where they rear before returning to the tributary stream to spawn (Fraley and Shepard 1989). These migratory forms occur where conditions allow movement from spawning locations to downstream waters that provide greater foraging opportunities (Dunham and Rieman 1999). Resident and migratory forms may occur together, and either form can produce resident or migratory offspring (Rieman and McIntyre 1993). The ability to migrate is important to the persistence of local bull trout populations (Rieman and McIntyre 1993). The identification of migratory corridors can help focus habitat protection efforts. Determining the life history form(s) that comprise local populations, the timing of seasonal movements, and the geographic extent of these movements are critical to bull trout protection and recovery efforts. This section describes work accomplished in 2001 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In the Grande Ronde and Walla Walla basins, we continued to monitor the movements of bull trout with radio transmitters applied in 1998 (Hemmingsen, Bellerud, Gunckel and Howell 2001) and 1999 (Hemmingsen, Gunckel and Howell 2001). No new radio transmitters were applied to bull trout of the upper John Day River subbasin, Mill Creek (Walla Walla Basin), or the Grande Ronde Basin in 2001. In Mill Creek, we used traps for the fourth consecutive year to obtain data on migrant bull trout. With these traps, we intended to determine the timing of bull trout movements both upstream and downstream, and to determine the relative abundance and size of migrant fish. No traps were operated in the John Day Basin in 2001.

Hemmingsen, Alan R.; Gunckel, Stephanie L.; Sankovich, Paul M.; Howell, Philip J.

2002-12-01

125

Does life-history variability in salmonids affect habitat use by juveniles? A comparison among streams open and closed to anadromy.  

PubMed

1. Migratory and resident forms of salmonids coexist in many river systems. Although such coexistence is widespread, little is known about its ecological basis and no studies have compared the habitat use of premigratory juveniles and residents. 2. We employed a comparative approach to explore the differential habitat use of juvenile anadromous and resident brook trout. This required the investigation of habitat use in streams closed to anadromy, containing only resident brook trout Salvelinus fontinalis ('resident-only' streams) and streams open to anadromy, containing coexisting Atlantic salmon Salmo salar and anadromous and resident brook trout ('migrant-resident' streams). 3. We demonstrate that fast habitats (riffles) are occupied more frequently in streams with migratory brook trout relative to riffle habitats of streams with only resident brook trout. In contrast, occupation of slow current velocities (pools) was observed in both migrant-resident and resident-only streams as both stream types contain resident brook trout. The net effect is a wider distribution of occupied habitats (pool and riffles) in migrant-resident streams relative to resident-only streams, resulting in few, if any, unused habitats. 4. These results are consistent with previously reported bioenergetic, morphological and stable isotope differences observed between anadromous and resident brook trout. 5. Our findings suggest that a link exists between juvenile habitat use, metabolic costs and life-history strategies. PMID:16689952

Morinville, Geneviève R; Rasmussen, Joseph B

2006-05-01

126

Salmon Life Histories, Habitat, and Food Webs in the Columbia River Estuary: An Overview of Research Results, 2002-2006.  

SciTech Connect

From 2002 through 2006 we investigated historical and contemporary variations in juvenile Chinook salmon Oncorhynchus tshawytscha life histories, habitat associations, and food webs in the lower Columbia River estuary (mouth to rkm 101). At near-shore beach-seining sites in the estuary, Chinook salmon occurred during all months of the year, increasing in abundance from January through late spring or early summer and declining rapidly after July. Recently emerged fry dispersed throughout the estuary in early spring, and fry migrants were abundant in the estuary until April or May each year. Each spring, mean salmon size increased from the tidal freshwater zone to the estuary mouth; this trend may reflect estuarine growth and continued entry of smaller individuals from upriver. Most juvenile Chinook salmon in the mainstem estuary fed actively on adult insects and epibenthic amphipods Americorophium spp. Estimated growth rates of juvenile Chinook salmon derived from otolith analysis averaged 0.5 mm d-1, comparable to rates reported for juvenile salmon Oncorhynchus spp. in other Northwest estuaries. Estuarine salmon collections were composed of representatives from a diversity of evolutionarily significant units (ESUs) from the lower and upper Columbia Basin. Genetic stock groups in the estuary exhibited distinct seasonal and temporal abundance patterns, including a consistent peak in the Spring Creek Fall Chinook group in May, followed by a peak in the Western Cascades Fall Chinook group in July. The structure of acanthocephalan parasite assemblages in juvenile Chinook salmon from the tidal freshwater zone exhibited a consistent transition in June. This may have reflected changes in stock composition and associated habitat use and feeding histories. From March through July, subyearling Chinook salmon were among the most abundant species in all wetland habitat types (emergent, forested, and scrub/shrub) surveyed in the lower 100 km of the estuary. Salmon densities within wetland habitats fell to low levels by July, similar to the pattern observed at mainstem beach-seining sites and coincident with high water temperatures that approached or exceeded 19 C by mid-summer. Wetland habitats were used primarily by small subyearling Chinook salmon, with the smallest size ranges (i.e., rarely exceeding 70 mm by the end of the wetland rearing season) at scrub/shrub forested sites above rkm 50. Wetland sites of all types were utilized by a diversity of genetic stock groups, including less abundant groups such as Interior Summer/Fall Chinook.

Bottom, Daniel L.; Anderson, Greer; Baptisa, Antonio

2008-08-01

127

Hunting influences the diel patterns in habitat selection by northern pintails Anas acuta  

USGS Publications Warehouse

Northern pintail Anas acuta (hereafter pintail) populations wintering within Suisun Marsh, a large estuarine managed wetland near San Francisco Bay, California,USA, have declined markedly over the last four decades. The reasons for this decline are unclear. Information on how hunting and other factors influence the selection of vegetation types and sanctuaries would be beneficial to manage pintail populations in SuisunMarsh. During 1991-1993, we radio-marked and relocated female pintails (individuals: N = 203, relocations: N = 7,688) within Suisun Marsh to investigate habitat selection during the non-breeding months (winter). We calculated selection ratios for different vegetation types and for sanctuaries, and examined differences in those ratios between hunting season (i.e. hunting and non-hunting), age (hatchyear and after-hatch-year), and time of day (daylight or night hours). We found that diel patterns in selection were influenced by hunting disturbance. For example, prior to the hunting season and during daylight hours, pintails selected areas dominated by brass buttons Cotula coronopifolia, a potentially important food source, usually outside of sanctuary boundaries. However, during the hunting season, pintails did not select brass buttons during daylight hours, but instead highly selected permanent pools, mostly within sanctuaries. Also, during the hunting season, pintails showed strong selection for brass buttons at night. Sanctuaries provided more area of permanent water pools than within hunting areas and appeared to function as important refugia during daylight hours of the hunting season. Wildlife managers should encourage large protected permanent pools adjacent to hunted wetlands to increase pintail numbers within wetland environments and responsibly benefit hunting opportunities while improving pintail conservation.

Casazza, Michael L.; Coates, Peter S.; Miller, Michael R.; Overton, Cory T.; Yparraguirre, Daniel R.

2012-01-01

128

White-tailed Deer Habitat Use and Movements Integrated with Factors Influencing Vehicle  

E-print Network

habitat use during fall/winter 3. Evaluate habitat and transportation factors associated with DVCs forests and loblolly pine plantations · 70 miles SE of Nashville in Coffee and Franklin counties · Eastern it didn't make it ­ Transportation factors · traffic volume · traffic speed · road density · lack

Gray, Matthew

129

Herb abundance and life-history traits in two contrasting alpine habitats in southern Norway  

Microsoft Academic Search

Colonisation is often a critical stage in the life history of plants, and recruitment success is expected to have a strong impact on plant frequencies especially among herbs. Several plant traits (seed size, plant height, leaf dry weight and specific leaf area) are suggested to be functionally important in early life stages, and the impact of such traits is expected

Gunnar Austrheim; Marianne Evju; Atle Mysterud

2005-01-01

130

Vacant Habitats in the Universe  

Microsoft Academic Search

The search for life on other planets usually makes the assumption that where there is a habitat, it will contain life. On the present-day Earth, uninhabited habitats (or vacant habitats) are rare, but might occur, for example, in subsurface oils or impact craters that have been thermally sterilized in the past. Beyond Earth, vacant habitats might similarly exist on inhabited

Charles S. Cockell

2010-01-01

131

Einstein's medical friends and their influence on his life.  

PubMed

Albert Einstein had at least six medical friends who influenced his thoughts. In each period (Munich, Switzerland, Berlin and Princeton) of his life, one could identify the medically qualified individuals with whom Einstein was in close contact. These include Max Talmey, Heinrich Zangger, George Nicolai, Hans Mühsam, Janos Plesch and Gustav Bucky. They probably enriched Einstein's life and thoughts significantly by being mentors, confidants, intellectual sparring partners and research collaborators to him. With Mühsam, Einstein published a paper in a German medical journal. In collaboration with Bucky, he also received a US patent for a light-intensity self-adjusting camera in 1936. PMID:8676763

Kantha, S S

1996-03-01

132

Societal Influences on Health and Life-styles  

PubMed Central

Strong sociocultural forces affect individual attitudes toward health and choice of life-style. Economic deprivation fosters negative health behaviors. Positive health habits are reinforced by discrete societal groups. The news media, particularly television, disseminate much useful health information, though the overall educational value is diminished by the content of commercial messages and programming. The automobile is a major societal influence, but neither individual drivers nor the car manufacturers give enough priority to highway safety, leaving that role to governmental regulation. American industry is becoming a positive influence in the encouragement of good health habits, and fashion is lately an important ally in personal health maintenance. PMID:6523860

Ulmer, David D.

1984-01-01

133

Bull Trout Life History, Genetics, Habitat Needs, and Limiting Fact in Central and Northeast Oregon. Annual Report 1999.  

SciTech Connect

This section describes work accomplished in 1999 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout Salvelinus confluentus and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In all three basins we used radio telemetry to determine the seasonal movements of bull trout. In the John Day and Walla Walla basins we also used traps to capture migrant bull trout. With these traps, we intended to determine the timing of bull trout movements both upstream and downstream, determine the relative abundance, size and age of migrant fish, and capture bull trout to be implanted with radio transmitters. In the John Day basin, we captured adult and juvenile bull trout from the upper John Day River and its tributaries, Call Creek, Reynolds Creek, and Roberts Creek. In the Walla Walla basin, we captured adult and juvenile bull trout from Mill Creek.

Hemmingsen, Alan R.; Gunckel, Stephanie L.; Howell, Philip J.

2001-08-01

134

Floral and nesting resources, habitat structure, and fire influence bee distribution across an open-forest gradient  

USGS Publications Warehouse

Given bees' central effect on vegetation communities, it is important to understand how and why bee distributions vary across ecological gradients. We examined how plant community composition, plant diversity, nesting suitability, canopy cover, land use, and fire history affected bee distribution across an open-forest gradient in northwest Indiana, USA, a gradient similar to the historic Midwest United States landscape mosaic. When considered with the other predictors, plant community composition was not a significant predictor of bee community composition. Bee abundance was negatively related to canopy cover and positively to recent fire frequency, bee richness was positively related to plant richness and abundance of potential nesting resources, and bee community composition was significantly related to plant richness, soil characteristics potentially related to nesting suitability, and canopy cover. Thus, bee abundance was predicted by a different set of environmental characteristics than was bee species richness, and bee community composition was predicted, in large part, by a combination of the significant predictors of bee abundance and richness. Differences in bee community composition along the woody vegetation gradient were correlated with relative abundance of oligolectic, or diet specialist, bees. Because oligoleges were rarer than diet generalists and were associated with open habitats, their populations may be especially affected by degradation of open habitats. More habitat-specialist bees were documented for open and forest/scrub habitats than for savanna/woodland habitats, consistent with bees responding to habitats of intermediate woody vegetation density, such as savannas, as ecotones rather than as distinct habitat types. Similarity of bee community composition, similarity of bee abundance, and similarity of bee richness between sites were not significantly related to proximity of sites to each other. Nestedness analysis indicated that species composition in species-poor sites was not merely a subset of species composition at richer sites. The lack of significant proximity or nestedness effects suggests that factors at a small spatial scale strongly influence bees' use of sites. The findings indicate that patterns of plant diversity, nesting resource availability, recent fire, and habitat shading, present at the scale of a few hundred meters, are key determinants of bee community patterns in the mosaic open-savanna-forest landscape. ?? 2010 by the Ecological Society of America.

Grundel, R.; Jean, R. P.; Frohnapple, K. J.; Glowacki, G. A.; Scott, P. E.; Pavlovic, N. B.

2010-01-01

135

Natural and anthropogenic influences on a red-crowned crane habitat in the Yellow River Delta Natural Reserve, 1992-2008.  

PubMed

This study aims to assess the relative importance of natural and anthropogenic variables on the change of the red-crowned crane habitat in the Yellow River Nature Reserve, East China using multitempopral remote sensing and geographic information system. Satellite images were used to detect the change in potential crane habitat, from which suitable crane habitat was determined by excluding fragmented habitat. In this study, a principal component analysis (PCA) with seven variables (channel flow, rainfall, temperature, sediment discharge, number of oil wells, total length of roads, and area of settlements) and linear regression analyses of potential and suitable habitat against the retained principal components were applied to explore the influences of natural and anthropogenic factors on the change of the red-crowned crane habitat. The experimental results indicate that suitable habitat decreased by 5,935 ha despite an increase of 1,409 ha in potential habitat from 1992 to 2008. The area of crane habitat changed caused by natural drivers such as progressive succession, retrogressive succession, and physical fragmentation is almost the same as that caused by anthropogenic forces such as land use change and behavioral fragmentation. The PCA and regression analyses revealed that natural factors (e.g., channel flow, rainfall, temperature, and sediment discharge) play an important role in the crane potential habitat change and human disturbances (e.g., oil wells, roads, and settlements) jointly explain 51.8 % of the variations in suitable habitat area, higher than 48.2 % contributed by natural factors. Thus, it is vital to reduce anthropogenic influences within the reserve in order to reverse the decline in the suitable crane habitat. PMID:24526617

Wang, Hong; Gao, Jay; Pu, Ruiliang; Ren, Liliang; Kong, Yan; Li, He; Li, Ling

2014-07-01

136

Influence of habitat complexity and landscape configuration on pollination and seed-dispersal interactions of wild cherry trees.  

PubMed

Land-use intensification is a major cause for the decline in species diversity in human-modified landscapes. The loss of functionally important species can reduce a variety of ecosystem functions, such as pollination and seed dispersal, but the intricate relationships between land-use intensity, biodiversity and ecosystem functioning are still contentious. Along a gradient from forest to intensively used farmland, we quantified bee species richness, visitation rates of bees and pollination success of wild cherry trees (Prunus avium). We analysed the effects of structural habitat diversity at a local scale and of the proportion of suitable habitat around each tree at a landscape scale. We compared these findings with those from previous studies of seed-dispersing birds and mammals in the same model system and along the same land-use gradient. Bee species richness and visitation rates were found to be highest in structurally simple habitats, whereas bird species richness--but not their visitation rates--were highest in structurally complex habitats. Mammal visitation rates were only influenced at the landscape scale. These results show that different functional groups of animals respond idiosyncratically to gradients in habitat and landscape structure. Despite strong effects on bees and birds, pollination success and bird seed removal did not differ along the land-use gradient at both spatial scales. These results suggest that mobile organisms, such as bees and birds, move over long distances in intensively used landscapes and thereby buffer pollination and seed-dispersal interactions. We conclude that measures of species richness and interaction frequencies are not sufficient on their own to understand the ultimate consequences of land-use intensification on ecosystem functioning. PMID:21818655

Breitbach, Nils; Tillmann, Svenja; Schleuning, Matthias; Grünewald, Claudia; Laube, Irina; Steffan-Dewenter, Ingolf; Böhning-Gaese, Katrin

2012-02-01

137

Hatching phenology, life history and egg bank size of fairy shrimp Branchipodopsis spp. (Branchiopoda, Crustacea) in relation to the ephemerality of their rock pool habitat  

Microsoft Academic Search

In temporary aquatic habitats, permanence and the severe disturbance associated with desiccation are strong selective agents\\u000a expected to lead to differentiation in life history strategies in populations experiencing different disturbance regimes.\\u000a Besides optimal timing of hatching of dormant life stages, maturation and reproduction, pool inhabitants also benefit from\\u000a the acquisition of reliable cues for the quality of the ambient environment.

Bram Vanschoenwinkel; Maitland Seaman; Luc Brendonck

2010-01-01

138

Local habitat and landscape influence predation of bird nests on afforested Mediterranean cropland  

NASA Astrophysics Data System (ADS)

Afforestation programs such as the one promoted by the EU Common Agrarian Policy have contributed to spread tree plantations on former cropland. Nevertheless these afforestations may cause severe damage to open habitat species, especially birds of high conservation value. We investigated predation of artificial bird nests at young tree plantations and at the open farmland habitat adjacent to the tree plantations in central Spain. Predation rates were very high at both tree plantations (95.6%) and open farmland habitat (94.2%) after two and three week exposure. Plantation edge/area ratio and development of the tree canopy decreased predation rates and plantation area and magpie (Pica pica) abundance increased predation rates within tree plantations, which were also affected by land use types around plantations. The area of nearby tree plantations (positive effect), distance to the tree plantation edge (negative effect), and habitat type (mainly attributable to the location of nests in vineyards) explained predation rates at open farmland habitat. We conclude that predation rates on artificial nests were particularly high and rapid at or nearby large plantations, with high numbers of magpies and low tree development, and located in homogenous landscapes dominated by herbaceous crops and pastures with no remnants of semi-natural woody vegetation. Landscape planning should not favour tree plantations as the ones studied here in Mediterranean agricultural areas that are highly valuable for ground-nesting bird species.

Sánchez-Oliver, J. S.; Rey Benayas, J. M.; Carrascal, L. M.

2014-07-01

139

Habitat type influences endocrine stress response in the degu (Octodon degus).  

PubMed

While many studies have examined whether the stress response differs between habitats, few studies have examined this within a single population. This study tested whether habitat differences, both within-populations and between-populations, relate to differences in the endocrine stress response in wild, free-living degus (Octodon degus). Baseline cortisol (CORT), stress-induced CORT, and negative feedback efficacy were measured in male and female degus from two sites and three habitats within one site during the mating/early gestation period. Higher quality cover and lower ectoparasite loads were associated with lower baseline CORT concentrations. In contrast, higher stress-induced CORT but stronger negative feedback efficacy were associated with areas containing higher quality forage. Stress-induced CORT and body mass were positively correlated in female but not male degus across all habitats. Female degus had significantly higher stress-induced CORT levels compared to males. Baseline CORT was not correlated with temperature at time of capture and only weakly correlated with rainfall. Results suggest that degus in habitats with good cover quality, low ectoparasite loads, and increased food availability have decreased endocrine stress responses. PMID:23518483

Bauer, Carolyn M; Skaff, Nicholas K; Bernard, Andrew B; Trevino, Jessica M; Ho, Jacqueline M; Romero, L Michael; Ebensperger, Luis A; Hayes, Loren D

2013-06-01

140

Matrix habitat and plant damage influence colonization of purple loosestrife patches by specialist leaf-beetles.  

PubMed

The characteristics of the matrix, that is, the unsuitable habitat connecting host-plant patches may facilitate or limit herbivore movement thus affecting their population dynamics. We evaluated the effect of matrix habitat, distance between patches, and plant damage on movement of two leaf-beetles (Galerucella calmariensis Linnaeus and G. pusilla Duft) introduced to North America as biocontrol agents of the invasive purple loosestrife (Lythrum salicaria Linnaeus). Mark-recapture/resight experiments indicated (1) that leaf-beetles are more likely to colonize purple loosestrife patches surrounded by meadow than forest; (2) that previously attacked purple loosestrife plants are more likely to be colonized by Galerucella spp. than unattacked plants, especially in the forest habitat; and (3) that leaf beetle colonization of purple loosestrife decreased with distance from release point. Low colonization rates of purple loosestrife patches embedded in forests suggest either insufficient detection or active avoidance of such habitats. Biological control programs intend to manage dispersal of specialized insect herbivores for the purpose of sufficient and sustained control of their host plants. Such management needs to be informed by knowledge of interactions of habitat structure, plant damage, and dispersal capabilities of herbivores to facilitate release programs and control at the local and regional level. PMID:22251719

Dávalos, A; Blossey, B

2011-10-01

141

Does predation risk influence habitat use by northern redbelly dace Phoxinus eos at different spatial scales?  

PubMed

This study investigated the relationship between spatial variations in predation risk and abundance of northern redbelly dace Phoxinus eos at both macroscale (littoral v. pelagic zones) and microscale (structured v. open water habitats in the littoral zone) of Canadian Shield lakes. Minnow traps were placed in both structured and open water habitats in the littoral zone of 13 Canadian Shield lakes, and estimates of the relative predation risk of P. eos in both the pelagic and the littoral zones were obtained from tethering experiments. Results showed that (1) the mean abundance of P. eos in the littoral zone was positively correlated with the relative predation risk in the pelagic zone, (2) P. eos preferentially used structured over open water habitats in the littoral zone and (3) this preference was not related to the relative predation risk in the littoral zone but decreased as the relative predation risk increased in the pelagic zone. At the lake level, these results support the hypothesis that P. eos enter the littoral zone to avoid pelagic piscivores. At the littoral zone level, the results do not necessarily contradict the widely accepted view that P. eos preferentially use structured over open habitats to reduce their predation risk, but suggest that flexibility in antipredator tactics (e.g. shelter use v. shoaling) could explain the spatial distribution of P. eos between structured and open water habitats. PMID:20735640

Dupuch, A; Magnan, P; Bertolo, A; Dill, L M; Proulx, M

2009-05-01

142

Robotic ecological mapping: Habitats and the search for life in the Atacama Desert  

Microsoft Academic Search

As part of the three-year ‘Life in the Atacama’ (LITA) project, plant and microbial abundance were mapped within three sites in the Atacama Desert, Chile, using an automated robotic rover. On-board fluorescence imaging of six biological signatures (e.g., chlorophyll, DNA, proteins) was used to assess abundance, based on a percent positive sample rating system and standardized robotic ecological transects. The

K. Warren-Rhodes; S. Weinstein; J. L. Piatek; J. Dohm; A. Hock; E. Minkley; D. Pane; L. A. Ernst; G. Fisher; S. Emani; A. S. Waggoner; N. A. Cabrol; D. S. Wettergreen; E. Grin; P. Coppin; Chong Diaz; J. Moersch; G. G. Oril; T. Smith; K. Stubbs; G. Thomas; M. Wagner; M. Wyatt; L. Ng Boyle

2007-01-01

143

Processes on the Young Earth and the Habitats of Early Life  

NASA Astrophysics Data System (ADS)

Conditions at the surface of the young (Hadean and early Archean) Earth were suitable for the emergence and evolution of life. After an initial hot period, surface temperatures in the late Hadean may have been clement beneath an atmosphere containing greenhouse gases over an ocean-dominated planetary surface. The first crust was mafic and it internally melted repeatedly to produce the felsic rocks that crystallized the Jack Hills zircons. This crust was destabilized during late heavy bombardment. Plate tectonics probably started soon after and had produced voluminous continental crust by the mid Archean, but ocean volumes were sufficient to submerge much of this crust. In the Hadean and early Archean, hydrothermal systems around abundant komatiitic volcanism may have provided suitable sites to host the earliest living communities and for the evolution of key enzymes. Evidence from the Isua Belt, Greenland, suggests life was present by 3.8 Gya, and by the mid-Archean, the geological record both in the Pilbara in Western Australia and the Barberton Greenstone Belt in South Africa shows that microbial life was abundant, probably using anoxygenic photosynthesis. By the late Archean, oxygenic photosynthesis had evolved, transforming the atmosphere and permitting the evolution of eukaryotes.

Arndt, Nicholas T.; Nisbet, Euan G.

2012-05-01

144

Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 2000.  

SciTech Connect

This section describes work accomplished in 2000 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout Salvelinus confluentus and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In all three basins we continued to monitor the movements of bull trout with radio transmitters applied in 1998 (Hemmingsen, Bellerud, Gunckel and Howell 2001) and 1999 (Hemmingsen, Gunckel and Howell 2001). No new radio transmitters were applied to bull trout of the upper John Day River subbasin, Mill Creek (Walla Walla Basin), or the Grande Ronde Basin in 2000. We did implant radio transmitters in two bull trout incidentally captured in the John Day River near the confluence of the North Fork John Day River. In Mill Creek, we used traps to capture migrant bull trout to obtain data for the third successive year in this stream. With these traps, we intended to determine the timing of bull trout movements both upstream and downstream, and to determine the relative abundance, size and age of migrant fish. Because we captured migrant bull trout with traps for three years in the upper John Day River and its tributaries (Hemmingsen, Bellerud, Buchanan, Gunckel, Shappart and Howell 2001; Hemmingsen, Bellerud, Gunckel and Howell 2001; Hemmingsen, Gunckel and Howell 2001) and traps were no longer needed to capture bull trout for radio-tagging, no traps were operated in the John Day Basin in 2000.

Hemmingsen, Alan R.; Gunckel, Stephanie L.; Sankovich, Paul M.; Howell, Philip J.

2001-11-01

145

Influence of prairie dogs ( Cynomys ludovicianus ) on habitat heterogeneity and mammalian diversity in Mexico  

Microsoft Academic Search

Prairie dogs are considered to be both a keystone species and an ecosystem engineer in grasslands. To partially test these hypotheses we evaluated burrow densities, soil removal, and mammal (i.e. rodents and carnivores) species composition, richness, diversity, and abundance in grasslands with and without prairie dogs (Cynomys ludovicianus) in north-western Mexico. We measured habitat heterogeneity as a function of burrow

Gerardo Ceballos; Jesús Pacheco; Rurik List

1999-01-01

146

On territorial behavior and other factors influencing habitat distribution in birds  

Microsoft Academic Search

Summary This example is provided so that non-theorists may see actual applications of the theory previously described. This study considered directly some of the components of Field Sparrow breeding success as a measure of habitat suitability, and found these to vary in a way which was inconsistent with hypotheses that territorial behavior either cues, or limits density. This study provides

Stephen Dewitt Fretwell

1969-01-01

147

Eating local: influences of habitat on the diet of little brown bats (Myotis lucifugus).  

PubMed

We employ molecular methods to profile the diet of the little brown bat, Myotis lucifugus, and describe spatial and temporal changes in diet over their maternity season. We identified 61 prey species of insects and 5 species of arachnid. The largest proportion of prey (?32%) were identified as species of the mass-emerging Ephemeroptera (mayfly) genus Caenis. Bats roosting in agricultural settings had lower dietary richness than those occupying a roost located on a forest fragment in a conservation area. We detected temporal fluctuations in diet over the maternity season. Dipteran (fly) species dominated the diet early in the season, replaced later by species of mayfly. Because our methodology provides species-level identification of prey, we were able to isolate environmental indicator species in the diet and draw conclusions about the location and type of their foraging habitat and the health of these aquatic systems. The species detected suggested that the bats use variable habitats; members of one agricultural roost foraged on insects originating in rivers or streams while those in another agricultural roost and the forest roost fed on insects from pond or lake environments. All source water for prey was of fair to good quality, though no species detected are intolerant of pollution thus the habitat cannot be classified as pristine. Our study outlines a model system to investigate the abiotic and biotic interactions between habitat factors through this simple food chain to the top predator. PMID:21366747

Clare, E L; Barber, B R; Sweeney, B W; Hebert, P D N; Fenton, M B

2011-04-01

148

Stand age and habitat influences on salamanders in Appalachian cove hardwood forests  

Microsoft Academic Search

We surveyed cove hardwood stands aged 15, 25, 50, and 285 years following clearcutting in the southern Appalachian Mountains of northem Georgia to assess the effects of stand age and stand habitat characteristics on salamander communities using drift-fence array and pitfall methodologies from May 1994 to April 1995. Over a 60,060 pitfall trapnight effort, we collected 3937 salamanders represented by

Michael A. Menzelc; Richard H. Odomd

149

Xylem cavitation vulnerability influences tree species' habitat preferences in miombo woodlands.  

PubMed

Although precipitation plays a central role in structuring Africa's miombo woodlands, remarkably little is known about plant-water relations in this seasonally dry tropical forest. Therefore, in this study, we investigated xylem vulnerability to cavitation for nine principal tree species of miombo woodlands, which differ in habitat preference and leaf phenology. We measured cavitation vulnerability (?(50)), stem-area specific hydraulic conductivity (K S), leaf specific conductivity (K L), seasonal variation in predawn water potential (?(PD)) and xylem anatomical properties [mean vessel diameter, mean hydraulic diameter, mean hydraulic diameter accounting for 95 % flow, and maximum vessel length (V L)]. Results show that tree species with a narrow habitat range (mesic specialists) were more vulnerable to cavitation than species with a wide habitat range (generalists). ?(50) for mesic specialists ranged between -1.5 and -2.2 MPa and that for generalists between -2.5 and -3.6 MPa. While mesic specialists exhibited the lowest seasonal variation in ?(PD), generalists displayed significant seasonal variations in ?(PD) suggesting that the two miombo habitat groups differ in their rooting depth. We observed a strong trade-off between K S and ?(50) suggesting that tree hydraulic architecture is one of the decisive factors setting ecological boundaries for principal miombo species. While vessel diameters correlated weakly (P > 0.05) with ?(50), V L was positively and significantly correlated with ?(50). ?(PD) was significantly correlated with ?(50) further reinforcing the conclusion that tree hydraulic architecture plays a significant role in species' habitat preference in miombo woodlands. PMID:23649755

Vinya, Royd; Malhi, Yadvinder; Fisher, Joshua B; Brown, Nick; Brodribb, Timothy J; Aragao, Luiz E

2013-11-01

150

Environmental and human influences on trumpeter swan habitat occupancy in Alaska  

USGS Publications Warehouse

Approximately 70-80% of the entire population of the Trumpeter Swan (Cygnus huccinator) depends for reproduction on wetlands in Alaska. This makes the identification of important habitat features and the effects of human interactions important for the species' long-term management. We analyzed the swan's habitat preferences in five areas throughout the state and found that swan broods occupied some wetland types, especially larger closed-basin wetlands such as lakes and ponds, at rates much higher than they occupied other wetland types, such as shrubby or forested wetlands. We also found a negative effect of transportation infrastructure on occupancy by broods in and around the Minto Flats State Game Refuge, Kenai National Wildlife Refuge, and Tetlin National Wildlife Refuge. This finding is of particular interest because much of the Minto Flats refuge has recently been licensed for oil and gas exploration and parts of the Kenai refuge have been developed in the past. We also investigated the potential effects of the shrinkage of closed-basin ponds on habitat occupancy by nesting Trumpeter Swans. We compared nesting swans' use of ponds with changes in the ponds' size and other characteristics from 1982 to 1996 and found no relationships between occupancy and changes in pond size. However, we believe that the recent and rapid growth of Trumpeter Swan populations in Alaska may become limited by available breeding habitat, and anthropogenic and climate-induced changes to the swan's breeding habitats have the potential to limit future production. ?? 2009 by The Cooper Ornithological Society. All rights reserved.

Schmidt, J.H.; Lindberg, M.S.; Johnson, D.S.; Schmultz, J.A.

2009-01-01

151

Depth and medium-scale spatial processes influence fish assemblage structure of unconsolidated habitats in a subtropical marine park.  

PubMed

Where biological datasets are spatially limited, abiotic surrogates have been advocated to inform objective planning for Marine Protected Areas. However, this approach assumes close correlation between abiotic and biotic patterns. The Solitary Islands Marine Park, northern NSW, Australia, currently uses a habitat classification system (HCS) to assist with planning, but this is based only on data for reefs. We used Baited Remote Underwater Videos (BRUVs) to survey fish assemblages of unconsolidated substrata at different depths, distances from shore, and across an along-shore spatial scale of 10 s of km (2 transects) to examine how well the HCS works for this dominant habitat. We used multivariate regression modelling to examine the importance of these, and other environmental factors (backscatter intensity, fine-scale bathymetric variation and rugosity), in structuring fish assemblages. There were significant differences in fish assemblages across depths, distance from shore, and over the medium spatial scale of the study: together, these factors generated the optimum model in multivariate regression. However, marginal tests suggested that backscatter intensity, which itself is a surrogate for sediment type and hardness, might also influence fish assemblages and needs further investigation. Species richness was significantly different across all factors: however, total MaxN only differed significantly between locations. This study demonstrates that the pre-existing abiotic HCS only partially represents the range of fish assemblages of unconsolidated habitats in the region. PMID:24824998

Schultz, Arthur L; Malcolm, Hamish A; Bucher, Daniel J; Linklater, Michelle; Smith, Stephen D A

2014-01-01

152

Depth and Medium-Scale Spatial Processes Influence Fish Assemblage Structure of Unconsolidated Habitats in a Subtropical Marine Park  

PubMed Central

Where biological datasets are spatially limited, abiotic surrogates have been advocated to inform objective planning for Marine Protected Areas. However, this approach assumes close correlation between abiotic and biotic patterns. The Solitary Islands Marine Park, northern NSW, Australia, currently uses a habitat classification system (HCS) to assist with planning, but this is based only on data for reefs. We used Baited Remote Underwater Videos (BRUVs) to survey fish assemblages of unconsolidated substrata at different depths, distances from shore, and across an along-shore spatial scale of 10 s of km (2 transects) to examine how well the HCS works for this dominant habitat. We used multivariate regression modelling to examine the importance of these, and other environmental factors (backscatter intensity, fine-scale bathymetric variation and rugosity), in structuring fish assemblages. There were significant differences in fish assemblages across depths, distance from shore, and over the medium spatial scale of the study: together, these factors generated the optimum model in multivariate regression. However, marginal tests suggested that backscatter intensity, which itself is a surrogate for sediment type and hardness, might also influence fish assemblages and needs further investigation. Species richness was significantly different across all factors: however, total MaxN only differed significantly between locations. This study demonstrates that the pre-existing abiotic HCS only partially represents the range of fish assemblages of unconsolidated habitats in the region. PMID:24824998

Schultz, Arthur L.; Malcolm, Hamish A.; Bucher, Daniel J.; Linklater, Michelle; Smith, Stephen D. A.

2014-01-01

153

Adjacent Habitat Influence on Stink Bug (Hemiptera: Pentatomidae) Densities and the Associated Damage at Field Corn and Soybean Edges  

PubMed Central

The local dispersal of polyphagous, mobile insects within agricultural systems impacts pest management. In the mid-Atlantic region of the United States, stink bugs, especially the invasive Halyomorpha halys (Stål 1855), contribute to economic losses across a range of cropping systems. Here, we characterized the density of stink bugs along the field edges of field corn and soybean at different study sites. Specifically, we examined the influence of adjacent managed and natural habitats on the density of stink bugs in corn and soybean fields at different distances along transects from the field edge. We also quantified damage to corn grain, and to soybean pods and seeds, and measured yield in relation to the observed stink bug densities at different distances from field edge. Highest density of stink bugs was limited to the edge of both corn and soybean fields. Fields adjacent to wooded, crop and building habitats harbored higher densities of stink bugs than those adjacent to open habitats. Damage to corn kernels and to soybean pods and seeds increased with stink bug density in plots and was highest at the field edges. Stink bug density was also negatively associated with yield per plant in soybean. The spatial pattern of stink bugs in both corn and soybeans, with significant edge effects, suggests the use of pest management strategies for crop placement in the landscape, as well as spatially targeted pest suppression within fields. PMID:25295593

Venugopal, P. Dilip; Coffey, Peter L.; Dively, Galen P.; Lamp, William O.

2014-01-01

154

Health Related Quality of Life and Influencing Factors among Welders  

PubMed Central

Background Occupational exposure to welding fumes is a serious occupational health problem all over the world. Welders are exposed to many occupational hazards; these hazards might cause some occupational diseases. The aim of the study was to assess the health related quality of life (HRQL) of electric welders in Shanghai China and explore influencing factors to HRQL of welders. Methods 301 male welders (without pneumoconiosis) and 305 non-dust male workers in Shanghai were enrolled in this study. Short Form-36 (SF-36) health survey questionnaires were applied in this cross-sectional study. Socio-demographic, working and health factors were also collected. Multiple stepwise regress analysis was used to identify significant factors related to the eight dimension scores. Results Six dimensions including role-physical (RP), bodily pain (BP), general health (GH), validity (VT), social function (SF), and mental health (MH) were significantly worse in welders compared to non-dust workers. Multiple stepwise regress analysis results show that native place, monthly income, quantity of children, drinking, sleep time, welding type, use of personal protective equipment (PPE), great events in life, and some symptoms including dizziness, discomfort of cervical vertebra, low back pain, cough and insomnia may be influencing factors for HRQL of welders. Among these factors, only sleep time and the use of PPE were salutary. Conclusions Some dimensions of HRQL of these welders have been affected. Enterprises which employ welders should take measures to protect the health of these people and improve their HRQL. PMID:25048102

Qin, Jingxiang; Liu, Wuzhong; Zhu, Jun; Weng, Wei; Xu, Jiaming; Ai, Zisheng

2014-01-01

155

Abundance, Behavior, and Habitat Utilization by Coho Salmon and Steelhead Trout in Fish Creek, Oregon, as Influenced by Habitat Enhancement, 1985 Annual Report.  

SciTech Connect

Construction and evaluation of salmonid habitat improvements on Fish Creek, a tributary of the upper Clackamas River, was continued in fiscal year 1985 by the Estacada Ranger District, Mt. Hood National Forest, and the Anadromous Fish Habitat Research Unit of the Pacific Northwest Forest and Range Experiment Station (PNW), USDA Forest Service. The study began in 1982 when PNW entered into an agreement with the Mt. Hood National Forest to evaluate fish habitat improvements in the Fish Creek basin on the Estacada Ranger District. The project was initially conceived as a 5-year effort (19824986) to be financed by Forest Service funds. Several factors limiting production of salmonids in the basin were identified during the first year of the study, and the scope of the habitat improvement effort was subsequently enlarged. The habitat improvement program and the evaluation of improvements were both expanded in mid-1983 when the Bonneville Power Administration entered into an agreement with the Mt. Hood National Forest to provide additional funding for work on Fish Creek. Habitat improvement work in the basin is designed to increase the annual number of chinook and coho salmon, and steelhead trout smolt outmigrants. The primary objectives of the evaluation include the: (1) Evaluation and quantification of changes in salmonid spawning and rearing habitat resulting from a variety of habitat Improvements. (2) Evaluation and quantification of changes in fish populations and biomass resulting from habitat improvements. (3) Evaluation of the cost-effectiveness of habitat improvements developed with BPA and Forest Service funds on Fish Creek. Several prototype enhancement projects were constructed and tested during the first three years of the study. The Intention was to identify successful techniques that could then be broadly applied within the bash. This stepwise procedure has been largely successful in identifying the most promising enhancement techniques for the Fish Creek basin. To date, 7-10 percent of the habitat area in the basin has been treated. When work on Fish Creek is completed, it is estimated that 50-60 percent of the total habitat area used by anadromous salmonids will have received some form of treatment. This annual progress report will focus on the projects completed in the basin In 1983, 1984, and 1985, and their evaluation. Winter habitat use and coho salmon and steelhead trout smolt production will also be emphasized.

Wolfe, John (Mount Hood National Forest, Clackamas River Ranger District, Estacada, OR); Everest, Fred H. (Oregon State University, Pacific Northwest Forest and Range Experiment Station, Corvallis, OR); Heller, David A. (Mount Hood National Forest, Gresham, OR)

1986-09-01

156

Influence of forest structure on habitat use by American marten in an industrial forest  

Microsoft Academic Search

American marten (Martes americana) are associated with late-successional, coniferous forests throughout much of their range. In the northeastern US, however, marten also occur in forests dominated by mid-successional, mixed coniferous–deciduous and deciduous stands. Structural attributes other than forest-stand age and dominant overstory type may be important determinants of habitat quality for marten. To identify structural conditions associated with patterns of

David C. Payer; Daniel J. Harrison

2003-01-01

157

Deer herbivory and habitat type influence long-term population dynamics of a rare wetland plant  

Microsoft Academic Search

Pinpointing the factors that alter the population viability of long-lived organisms, such as perennial plants, is especially\\u000a useful for informing conservation management policies for threatened and endangered species. In this study, I used 4 years\\u000a of demographic data on rare plant Polemonium vanbruntiae (Eastern Jacob’s ladder, Polemoniaceae) to determine how white-tailed deer herbivory and habitat type (wet meadow and forest\\u000a seep)

Laura Hill Bermingham

2010-01-01

158

Habitat Differences Influence Genetic Impacts of Human Land Use on the American Beech (Fagus grandifolia).  

PubMed

Natural reforestation after regional forest clearance is a globally common land-use sequence. The genetic recovery of tree populations in these recolonized forests may depend on the biogeographic setting of the landscape, for instance whether they are in the core or in the marginal part of the species' range. Using data from 501 individuals genotyped across 7 microsatellites, we investigated whether regional differences in habitat quality affected the recovery of genetic variation in a wind-pollinated tree species, American beech (Fagus grandifolia) in Massachusetts. We compared populations in forests that were recolonized following agricultural abandonment to those in remnant forests that have only been logged in both central inland and marginal coastal regions. Across all populations in our entire study region, recolonized forests showed limited reduction of genetic diversity as only observed heterozygosity was significantly reduced in these forests (H O = 0.520 and 0.590, respectively). Within inland region, this pattern was observed, whereas in the coast, recolonized populations exhibited no reduction in all genetic diversity estimates. However, genetic differentiation among recolonized populations in marginal coastal habitat increased (F st logged = 0.072; F st secondary = 0.249), with populations showing strong genetic structure, in contrast to inland region. These results indicate that the magnitude of recovery of genetic variation in recolonized populations can vary at different habitats. PMID:25138571

Lumibao, Candice Y; McLachlan, Jason S

2014-01-01

159

Soil Fertility, Salinity and Nematode Diversity Influenced by Tamarix ramosissima in Different Habitats in an Arid Desert Oasis  

NASA Astrophysics Data System (ADS)

The aim of this paper was to assess the influence of tamarisk shrubs on soil fertility, salinity and nematode communities in various habitats located in an arid desert-oasis region in northwest China. Three habitats were studied: sand dune, riparian zone and saline meadow, where tamarisk shrubs have been established in recent decades in order to vegetation restoration used as desertification control and saline land rehabilitation projects and become the dominant plant community. The parameters measured include soil organic carbon (SOC), total nitrogen, available phosphorus (P) and potassium (K), pH, salt component, and nematode community characteristics. Enrichment ratios (a comparison of the soil measurements between soils under canopy and in the open interspaces) for soil nutrients and salinity were used to evaluate fertility and salinity islands underneath the tamarisk shrubs. The soil nematode community was used as a biological indicator of soil condition. SOC and available P and K were higher beneath the plant canopy than in the open interspaces outside that canopy. The enrichment ratios for SOC and nutrients were highest for the sand dune habitat and tamarisk shrubs clearly created islands of greater salinity under the canopies. Nematode abundance per 100 g dry soil varied considerably between the locations and habitats, with the highest abundance found in sand dune and the lowest in saline meadow. A significantly higher nematode abundance and a lower trophic diversity were found in soils under the canopy compared to the soils in the open interspaces. With the exception of saline meadow, the abundance of bacterivores increased and fungivores decreased under the canopy relative to the open interspaces, and bacterivores dominated under the canopies in the sand dune and riparian habitats. The enrichment ratios for salinity were higher than for fertility, suggesting that improved soil fertility can not limit the impact of salinization beneath tamarisk shrubs. The adverse effect of salt accumulation on the soil environment should be taken into account when using tamarisk as restoration plant species, especially in saline meadow and controlling of tamarisk density should be considered when undertaking re-vegetation projects in the arid desert oasis regions.

Yong-zhong, Su; Xue-fen, Wang; Rong, Yang; Xiao, Yang; Wen-jie, Liu

2012-08-01

160

Soil fertility, salinity and nematode diversity influenced by Tamarix ramosissima in different habitats in an arid desert oasis.  

PubMed

The aim of this paper was to assess the influence of tamarisk shrubs on soil fertility, salinity and nematode communities in various habitats located in an arid desert-oasis region in northwest China. Three habitats were studied: sand dune, riparian zone and saline meadow, where tamarisk shrubs have been established in recent decades in order to vegetation restoration used as desertification control and saline land rehabilitation projects and become the dominant plant community. The parameters measured include soil organic carbon (SOC), total nitrogen, available phosphorus (P) and potassium (K), pH, salt component, and nematode community characteristics. Enrichment ratios (a comparison of the soil measurements between soils under canopy and in the open interspaces) for soil nutrients and salinity were used to evaluate fertility and salinity islands underneath the tamarisk shrubs. The soil nematode community was used as a biological indicator of soil condition. SOC and available P and K were higher beneath the plant canopy than in the open interspaces outside that canopy. The enrichment ratios for SOC and nutrients were highest for the sand dune habitat and tamarisk shrubs clearly created islands of greater salinity under the canopies. Nematode abundance per 100 g dry soil varied considerably between the locations and habitats, with the highest abundance found in sand dune and the lowest in saline meadow. A significantly higher nematode abundance and a lower trophic diversity were found in soils under the canopy compared to the soils in the open interspaces. With the exception of saline meadow, the abundance of bacterivores increased and fungivores decreased under the canopy relative to the open interspaces, and bacterivores dominated under the canopies in the sand dune and riparian habitats. The enrichment ratios for salinity were higher than for fertility, suggesting that improved soil fertility can not limit the impact of salinization beneath tamarisk shrubs. The adverse effect of salt accumulation on the soil environment should be taken into account when using tamarisk as restoration plant species, especially in saline meadow and controlling of tamarisk density should be considered when undertaking re-vegetation projects in the arid desert oasis regions. PMID:22610148

Yong-zhong, Su; Xue-fen, Wang; Rong, Yang; Xiao, Yang; Wen-jie, Liu

2012-08-01

161

Hydrologic Reconnaissance of Wetland-Bird Habitat in Areas With Potential to be Influenced by Water Produced During Coalbed Methane Production in the Northern Powder River Basin, MT  

NASA Astrophysics Data System (ADS)

The removal and disposal of ground water during production of coalbed methane has the potential to influence wetland-bird habitat in the Powder River Basin. Office analysis of wetland areas was conducted on National Wetland Inventory maps and Digital Orthophoto Quadrangles along the Tongue and Powder rivers in the northern Powder River Basin, Montana. Selected sites were palustrine emergent, large enough to be important to waterbirds, part of a wetland complex, not dependent on artificial water regimes, in an area with high potential for coalbed methane production, and judged to be accessible in the field. Several promising wetland areas were selected for field examination. Field investigation suggests that the most promising wetlands in oxbow cutoffs would not be productive sites. Only facultative not obligate wetland plants were observed, the topographic position of the wetlands suggested that flooding would be infrequent, and the stream flow would likely dilute the effect of produced water adjacent to these rivers. Fortuitously wetland-bird habitat not recognized on the National Wetland Inventory maps and Digital Orthophoto Quadrangles was observed along Rosebud Creek during the field reconnaissance. This habitat is not continuous. The lack of continuity is reflected in the soil surveys as well as in the reconnaissance field nvestigation. The Alluvial Land soil series corresponds to observed wetland areas but the extent of the wetland-bird habitat varies substantially within the soil unit. When the Korchea series is present, extensive wetland-bird habitat is not observed. Field and aerial photo analysis suggests that the presence of the habitat may be controlled by beaver, and/or by stratigraphic and structural elements that influence stream erosion. Human modification of the stream for irrigation purposes may impact habitat continuity in some areas. The "Rosebud" type wetland-bird habitat may have the potential to be influenced by coalbed methane water production and warrants further more detailed investigation to determine the areal extent of the habitat, to determine the factors that control the distribution of intermittent wetland-bird-habitat areas, and to better model whether and how water produced during coalbed methane development might influence wetland-bird habitat.

Custer, S. G.; Sojda, R. S.

2003-12-01

162

Influence of early-life nutrition on mortality and reproductive success during a subsequent famine  

E-print Network

-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition of metabolic diseases. developmental plasticity | silver spoon | human life-history | DoHAD Nutrition duringInfluence of early-life nutrition on mortality and reproductive success during a subsequent famine

Lummaa, Virpi

163

Modeling the influence of Peromyscus leucopus body mass, sex, and habitat on immature Dermacentor variabilis burden.  

PubMed

Immature (larvae and nymph) tick burden on rodents is an important determinant of adult tick population size and understanding infectious disease dynamics. The objective of this research was to build a descriptive model for immature Dermacentor variabilis burden on Peromyscus leucopus. Mice were live-trapped on two permanent grids in an old field and an early successional forest every other month between April and October, 2006-2009. Negative binomial regression was used to examine the association between immature D. variabilis burden and the host related variables of host habitat, body mass, and/or sex. The model containing all three variables had the lowest Akaike's Information Criterion (AIC), corrected AIC (AICc), and greatest AICc weight. Immature D. variabilis burden was positively associated with mice with higher body mass, male mice, and those captured in the field habitat. These data are consistent with studies from other tick-rodent systems and suggest that single factor models do not describe host burden. Variables other than those that are related to the host may also be important in describing the tick burden on rodents. The next step is to examine variables that affect tick development rate and questing behavior. PMID:23181857

Dallas, Tad A; Foré, Stephanie A; Kim, Hyun-Joo

2012-12-01

164

Whillans Ice Stream Subglacial Access Research Drilling (WISSARD): Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats (Invited)  

NASA Astrophysics Data System (ADS)

The WISSARD project is a large, NSF-funded, interdisciplinary initiative focused on scientific drilling, exploration, and investigation of Antarctic subglacial aquatic environments. The project consists of three interrelated components: (1) LISSARD - Lake and Ice Stream Subglacial Access Research Drilling, (2) RAGES - Robotic Access to Grounding-zones for Exploration and Science, and (3) GBASE - GeomicroBiology of Antarctic Subglacial Environments). A number of previous studies in West Antarctica highlighted the importance of understanding ice sheet interactions with water, either at the basal boundary where ice streams come in contact with active subglacial hydrologic and geological systems or at the marine margin where the ice sheet is exposed to forcing from the global ocean and sedimentation. Recent biological investigations of Antarctic subglacial environments show that they provide a significant habitat for life and source of bacterial carbon in a setting that was previously thought to be inhospitable. Subglacial microbial ecosystems also enhance biogeochemical weathering, mobilizing elements from long term geological storage. The overarching scientific objective of WISSARD is to examine the subglacial hydrological system of West Antarctica in glaciological, geological, microbiological, geochemical, and oceanographic contexts. Direct sampling will yield seminal information on these systems and test the overarching hypothesis that active hydrological systems connect various subglacial environments and exert major control on ice sheet dynamics, subglacial sediment transfer, geochemistry, metabolic and phylogenetic diversity, and biogeochemical transformations and geological records of ice sheet history. Technological advances during WISSARD will provide the US-science community with a capability to access and study sub-ice sheet environments. Developing this technological infrastructure will benefit the broader science community and it will be available for future use. Furthermore, these projects will pioneer an approach implementing recommendations from the National Research Council committee on Principles of Environmental Stewardship for the Exploration and Study of Subglacial Environments.

Tulaczyk, S. M.; Anandakrishnan, S.; Behar, A. E.; Christner, B. C.; Fisher, A. T.; Fricker, H. A.; Holland, D. M.; Jacobel, R. W.; Mikucki, J.; Mitchell, A. C.; Powell, R. D.; Priscu, J. C.; Scherer, R. P.; Severinghaus, J. P.

2009-12-01

165

Seasonal Movement and Habitat Use by Subadult Bull Trout in the Upper Flathead River System, Montana  

Microsoft Academic Search

Despite the importance of large-scale habitat connectivity to the threatened bull trout Salvelinus confluentus, little is known about the life history characteristics and processes influencing natural dispersal of migratory populations. We used radiotelemetry to investigate the seasonal movements and habitat use by subadult bull trout (i.e., fish that emigrated from natal streams to the river system) tracked for varying durations

Clint C. Muhlfeld; Brian Marotz

2005-01-01

166

Landscape alterations influence differential habitat use of nesting buteos and ravens within sagebrush ecosystem: implications for transmission line development  

USGS Publications Warehouse

A goal in avian ecology is to understand factors that influence differences in nesting habitat and distribution among species, especially within changing landscapes. Over the past 2 decades, humans have altered sagebrush ecosystems as a result of expansion in energy production and transmission. Our primary study objective was to identify differences in the use of landscape characteristics and natural and anthropogenic features by nesting Common Ravens (Corvus corax) and 3 species of buteo (Swainson's Hawk [Buteo swainsoni], Red-tailed Hawk [B. jamaicensis], and Ferruginous Hawk [B. regalis]) within a sagebrush ecosystem in southeastern Idaho. During 2007–2009, we measured multiple environmental factors associated with 212 nest sites using data collected remotely and in the field. We then developed multinomial models to predict nesting probabilities by each species and predictive response curves based on model-averaged estimates. We found differences among species related to nesting substrate (natural vs. anthropogenic), agriculture, native grassland, and edge (interface of 2 cover types). Most important, ravens had a higher probability of nesting on anthropogenic features (0.80) than the other 3 species (Artemisia spp.), favoring increased numbers of nesting ravens and fewer nesting Ferruginous Hawks. Our results indicate that habitat alterations, fragmentation, and forthcoming disturbances anticipated with continued energy development in sagebrush steppe ecosystems can lead to predictable changes in raptor and raven communities.

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

2014-01-01

167

The relative influence of geographic location and reach-scale habitat on benthic invertebrate assemblages in six ecoregions.  

PubMed

The objective of this study was to determine the relative influence of reach-specific habitat variables and geographic location on benthic invertebrate assemblages within six ecoregions across the Western USA. This study included 417 sites from six ecoregions. A total of 301 taxa were collected with the highest richness associated with ecoregions dominated by streams with coarse substrate (19-29 taxa per site). Lowest richness (seven to eight taxa per site) was associated with ecoregions dominated by fine-grain substrate. Principle component analysis (PCA) on reach-scale habitat separated the six ecoregions into those in high-gradient mountainous areas (Coast Range, Cascades, and Southern Rockies) and those in lower-gradient ecoregions (Central Great Plains and Central California Valley). Nonmetric multidimensional scaling (NMS) models performed best in ecoregions dominated by coarse-grain substrate and high taxa richness, along with coarse-grain substrates sites combined from multiple ecoregions regardless of location. In contrast, ecoregions or site combinations dominated by fine-grain substrate had poor model performance (high stress). Four NMS models showed that geographic location (i.e. latitude and longitude) was important for: (1) all ecoregions combined, (2) all sites dominated by coarse-grain sub strate combined, (3) Cascades Ecoregion, and (4) Columbia Ecoregion. Local factors (i.e. substrate or water temperature) seem to be overriding factors controlling invertebrate composition across the West, regardless of geographic location. PMID:18629444

Munn, Mark D; Waite, Ian R; Larsen, David P; Herlihy, Alan T

2009-07-01

168

Geographic and Habitat Origin Influence Biomass Production and Storage Translocation in the Clonal Plant Aegopodium podagraria  

PubMed Central

Through physiological integration, clonal plants can support ramets in unfavourable patches, exploit heterogeneously distributed resources and distribute resources that are taken up over large areas. Physiological integration generally increases in adverse conditions, but it is not well known which factors determine the evolution of physiological integration. The aim of this study was to investigate if clonal plants from Southern and Northern populations of the clonal herb Aegopodium podagraria differed in physiological integration in terms of translocation of carbon to the rhizomes, and in biomass production using a reciprocal transplant experiment. Aegopodium podagraria from shaded conditions have been suggested to share more resources than clones from open conditions and therefore, plants from forest and open populations within the Southern and Northern regions were included. The regional growing conditions greatly affected biomass production. Plants grown in North Sweden produced more biomass and allocated more biomass to shoots, while plants grown in South Sweden allocated more biomass to rhizomes. There was a regional origin effect as plants originating from North Sweden produced more biomass in both regions. Within the Northern region, plants from shaded habitats translocated more 14C to the rhizomes, suggesting more storage there than in plants from open habitats. In addition to genetic differentiation in biomass production between Northern and Southern populations, probably as a response to a shorter growing season in the North, there appeared to be genetic differentiation in physiological integration within the Northern region. This shows that both regional and local conditions need to be taken into account in future studies of genetic differentiation of physiological integration in clonal plants. PMID:24427305

D?Hertefeldt, Tina; Enestrom, Johanna M.; Pettersson, Lars B.

2014-01-01

169

Geographic and habitat origin influence biomass production and storage translocation in the clonal plant Aegopodium podagraria.  

PubMed

Through physiological integration, clonal plants can support ramets in unfavourable patches, exploit heterogeneously distributed resources and distribute resources that are taken up over large areas. Physiological integration generally increases in adverse conditions, but it is not well known which factors determine the evolution of physiological integration. The aim of this study was to investigate if clonal plants from Southern and Northern populations of the clonal herb Aegopodium podagraria differed in physiological integration in terms of translocation of carbon to the rhizomes, and in biomass production using a reciprocal transplant experiment. Aegopodium podagraria from shaded conditions have been suggested to share more resources than clones from open conditions and therefore, plants from forest and open populations within the Southern and Northern regions were included. The regional growing conditions greatly affected biomass production. Plants grown in North Sweden produced more biomass and allocated more biomass to shoots, while plants grown in South Sweden allocated more biomass to rhizomes. There was a regional origin effect as plants originating from North Sweden produced more biomass in both regions. Within the Northern region, plants from shaded habitats translocated more (14)C to the rhizomes, suggesting more storage there than in plants from open habitats. In addition to genetic differentiation in biomass production between Northern and Southern populations, probably as a response to a shorter growing season in the North, there appeared to be genetic differentiation in physiological integration within the Northern region. This shows that both regional and local conditions need to be taken into account in future studies of genetic differentiation of physiological integration in clonal plants. PMID:24427305

D'Hertefeldt, Tina; Eneström, Johanna M; Pettersson, Lars B

2014-01-01

170

Habitat characteristics influencing distribution of the freshwater mussel Pronodularia japanensis and potential impact on the Tokyo bitterling, Tanakia tanago.  

PubMed

The physical habitat characteristics associated with spatial distribution patterns of the freshwater mussel Pronodularia japanensis, which is used for oviposition by the Tokyo bitterling Tanakia tanago, were investigated in a small stream within a Tokyo bitterling protected area. The distribution of the mussels was found to be in an under-dispersed, non-random spatial pattern. Mussel occurrence correlated negatively with sediment softness, and positively with flow velocity, while mussel abundance was associated negatively with sediment softness and positively with sediment type (particle size). Furthermore, mussels were scarce in riverbed areas with a lack of sediment. These correlations suggest that the population dynamics of mussels and Tokyo bitterling may be influenced by changes in stream sediment conditions. To conserve the symbiosis between Tokyo bitterlings and mussels, a suitable benthic environment is required. PMID:21110716

Akiyama, Yoshihiro B; Maruyama, Takashi

2010-12-01

171

Volcaniclastic habitats for early life on Earth and Mars: A case study from ˜3.5 Ga-old rocks from the Pilbara, Australia  

NASA Astrophysics Data System (ADS)

Within the context of present and future in situ missions to Mars to investigate its habitability and to search for traces of life, we studied the habitability and traces of past life in ˜3.5 Ga-old volcanic sands deposited in littoral environments an analogue to Noachian environments on Mars. The environmental conditions on Noachian Mars (4.1-3.7 Ga) and the Early Archaean (4.0-3.3 Ga) Earth were, in many respects, similar: presence of liquid water, dense CO 2 atmosphere, availability of carbon and bio-essential elements, and availability of energy. For this reason, information contained in Early Archaean terrestrial rocks concerning habitable conditions (on a microbial scale) and traces of past life are of relevance in defining strategies to be used to identify past habitats and past life on Mars. One such example is the 3.446 Ga-old Kitty's Gap Chert in the Pilbara Craton, NW. Australia. This formation consists of volcanic sediments deposited in a coastal mudflat environment and is thus a relevant analogue for sediments deposited in shallow water environments on Noachian Mars. Two main types of habitat are represented, a volcanic (lithic) habitat and planar stabilized sediment surfaces in sunlit shallow waters. The sediments hosted small (<1 ?m in size) microorganisms that formed colonies on volcanic particle surfaces and in pore waters within the volcanic sediments, as well as biofilms on stabilised sediment surfaces. The microorganisms included coccoids, filaments and rare rod-shaped organisms associated with microbial polymer (EPS). The preserved microbial community was apparently dominated by chemotrophic organisms but some locally transported filaments and filamentous mat fragments indicate that possibly photosynthetic mats formed nearby. Both microorganisms and sediments were silicified during very early diagenesis. There are no macroscopic traces of fossilised life in these volcanic sediments and sophisticated instrumentation and specialized sample preparation techniques are required to establish the biogenicity and syngenicity of the traces of past life. The fact that the traces of life are cryptic, and the necessity of using sophisticated instrumentation, reinforces the challenges and difficulties of in situ robotic missions to identify past life on Mars. We therefore recommend the return of samples from Mars to Earth for a definitive search for traces of life.

Westall, Frances; Foucher, Frédéric; Cavalazzi, Barbara; de Vries, Sjoukje T.; Nijman, Wouter; Pearson, Victoria; Watson, Jon; Verchovsky, Alexander; Wright, Ian; Rouzaud, Jean-Noel; Marchesini, Daniele; Anne, Severine

2011-08-01

172

Environmental constraints influencing survival of an African parasite in a north temperate habitat: effects of temperature on egg development.  

PubMed

Factors affecting survival of parasites introduced to new geographical regions include changes in environmental temperature. Protopolystoma xenopodis is a monogenean introduced with the amphibian Xenopus laevis from South Africa to Wales (probably in the 1960s) where low water temperatures impose major constraints on life-cycle processes. Effects were quantified by maintenance of eggs from infections in Wales under controlled conditions at 10, 12, 15, 18, 20 and 25°C. The threshold for egg viability/ development was 15°C. Mean times to hatching were 22 days at 25°C, 32 days at 20°C, extending to 66 days at 15°C. Field temperature records provided calibration of transmission schedules. Although egg production continues year-round, all eggs produced during >8 months/ year die without hatching. Output contributing significantly to transmission is restricted to 10 weeks (May-mid-July). Host infection, beginning after a time lag of 8 weeks for egg development, is also restricted to 10 weeks (July-September). Habitat temperatures (mean 15·5°C in summer 2008) allow only a narrow margin for life-cycle progress: even small temperature increases, predicted with 'global warming', enhance infection. This system provides empirical data on the metrics of transmission permitting long-term persistence of isolated parasite populations in limiting environments. PMID:21524323

Tinsley, R C; York, J E; Everard, A L E; Stott, L C; Chapple, S J; Tinsley, M C

2011-07-01

173

Abstract The influence of environmental variables and habitat on growth and survival of juvenile gadoid  

E-print Network

the ecology of its early life stages. Pacific cod spawn demersal and semi-adhesive eggs (Yamamoto 1939. Abookire (&) Alaska Fisheries Science Center, Kodiak Laboratory, National Marine Fisheries Service, NOAA. Jump Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, 7600 Sand Point Way NE

174

Does Autocthonous Primary Production Influence Oviposition by Aedes japonicus japonicus (Diptera: Culicidae) in Container Habitats?  

PubMed Central

Aedes (Finlaya) japonicus japonicus (Theobald) (Diptera: Culicidae) is recently invasive in North America and has expanded its range rapidly since 1998. Throughout its native and expanded range, Ae. j. japonicus larvae are commonly observed in many types of natural and artificial water-filled containers that vary in organic matter content and exposure to sunlight. Larvae are most often found in containers with decaying leaf material or algae, and we postulated that the added autocthonous primary production from algae could be both an important food source for larvae and an influential oviposition attractant to adult Ae. j. japonicus. We tested this hypothesis by placing plastic containers with varied levels of shading to manipulate algal density in the field, and then monitored oviposition by natural populations of Ae. j. japonicus. Over 99% of larvae hatching from eggs laid on the walls of our containers were Ae. j. japonicus, indicating that this species is a dominant colonizer of artificial containers in the study areas. Although full shading treatments effectively reduced algal biomass (significant reduction in chlorophyll a levels), at only one of three sites did this appear to affect Ae. j. japonicus oviposition. We conclude that algae in larval habitats are not a major factor in oviposition choices of adult Ae. j. japonicus females except when in situ primary production is high enough to substantially alter overall organic matter content cues. PMID:23427654

LORENZ, AMANDA R.; WALKER, EDWARD D.; KAUFMAN, MICHAEL G.

2014-01-01

175

Does autocthonous primary production influence oviposition by Aedes japonicus japonicus (Diptera: Culicidae) in container habitats?  

PubMed

Aedes (Finlaya) japonicus japonicus (Theobald) (Diptera: Culicidae) is recently invasive in North America and has expanded its range rapidly since 1998. Throughout its native and expanded range, Ae. j. japonicus larvae are commonly observed in many types of natural and artificial water-filled containers that vary in organic matter content and exposure to sunlight. Larvae are most often found in containers with decaying leaf material or algae, and we postulated that the added autocthonous primary production from algae could be both an important food source for larvae and an influential oviposition attractant to adult Ae. j. japonicus. We tested this hypothesis by placing plastic containers with varied levels of shading to manipulate algal density in the field, and then monitored oviposition by natural populations of Ae. j. japonicus. Over 99% of larvae hatching from eggs laid on the walls of our containers were Ae. j. japonicus, indicating that this species is a dominant colonizer of artificial containers in the study areas. Although full shading treatments effectively reduced algal biomass (significant reduction in chlorophyll a levels), at only one of three sites did this appear to affect Ae. j. japonicus oviposition. We conclude that algae in larval habitats are not a major factor in oviposition choices of adult Ae. j. japonicus females except when in situ primary production is high enough to substantially alter overall organic matter content cues. PMID:23427654

Lorenz, Amanda R; Walker, Edward D; Kaufman, Michael G

2013-01-01

176

Habitat use by the endangered Karner blue butterfly in oak woodlands: The influence of canopy cover  

USGS Publications Warehouse

The Karner blue butterfly Lycaeides melissa samuelis is an endangered species residing in the Great Lakes and northeastern regions of the United States. Increased canopy cover is a major factor implicated in the decline of the Karner blue at many locales. Therefore, we examined how the butterfly's behavior varied with canopy cover. Adult males at Indiana Dunes National Lakeshore used habitat under canopy openings for nearly 90% of their activities; females used openings and shaded areas more equally. The frequency of oviposition on the sole host plant, wild lupine Lupinus perennis, was highest under 30-60% canopy cover even though lupine was more abundant in more open areas. Larvae fed preferentially on larger lupine plants and on lupines in denser patches. However, lupines were generally larger in the shade. Therefore, shade-related trade-offs existed between lupine abundance and distribution of larval feeding and oviposition. Also, heterogeneity of shading by sub-canopy woody vegetation was greater at oviposition sites than at sites where lupine did not grow. Given the importance of shade heterogeneity, a mixture of canopy openings and shade, on a scale similar to daily adult movement range, should be beneficial for this butterfly.

Grundel, R.; Pavlovic, N. B.; Sulzman, C. L.

1998-01-01

177

Habitat use by the endangered Karner blue butterfly in oak woodlands: The influence of canopy cover  

USGS Publications Warehouse

The Karner blue butterfly Lycaeides melissa samuelis is an endangered species residing in the Great Lakes and northeastern regions of the United States. Increased canopy cover is a major factor implicated in the decline of the Karner blue at many locales. Therefore, we examined how the butterfly's behavior varied with canopy cover. Adult males at Indiana Dunes National Lakeshore used habitat under canopy openings for nearly 90% of their activities; females used openings and shaded areas more equally. The frequency of oviposition on the sole host plant, wild lupine Lupinus perennis, was highest under 30-60% canopy cover even though lupine was more abundant in more open areas. Larvae fed preferentially on larger lupine plants and on lupines in denser patches. However, lupines were generally large in the shade. Therefore, shade-related trade-offs existed between lupine abundance and distribution of larval feeding and oviposition. Also, heterogeneity of shading by sub-canopy woody vegetation was greater at oviposition sites than at sites where lupine did not grow. Given the importance of shade heterogeneity, a mixture of canopy opening and shades, on a scale similar to daily adult movement range, should be beneficial for this butterfly.

Grundel, Ralph; Pavlovic, Noel B.; Sulzman, Christina L.

1998-01-01

178

Influence of habitat on density, species richness, and size distribution of groupers in the upper Florida Keys, United States of America and central Bahamas  

Microsoft Academic Search

The influence of habitat on the density, species richness, and size distribution of groupers (Pisces: Serranidae) was studied in the upper Florida Keys, USA and the Exuma Cays Land and Sea Park (ECLSP), central Bahamas. Four reef types were examined: relict spur and groove; high-relief spur and groove; relict reef flat; and patch reefs.The size distribution of groupers differed among

Robert Daniel Sluka

1995-01-01

179

Influence of 4-H Horse Project Involvement on Development of Life Skills  

ERIC Educational Resources Information Center

Four-H horse project members who competed in non-riding horse contests were surveyed to evaluate the influence of their horse project participation on life-skill development. Contests in which youth competed included Horse Bowl, Demonstrations, Public Speaking, and Art. Youth indicated a positive influence on both life-skill development and horse…

Anderson, K. P.; Karr-Lilienthal, L.

2011-01-01

180

Environmental, behavioral, and habitat variables influencing body temperature in radio-tagged bullsnakes, Pituophis catenifer sayi  

Microsoft Academic Search

Studies regarding the thermal ecology of snakes are important to understanding their life histories. Yet, little is known about the thermal ecology of the North American genus Pituophis, which includes the bullsnake (Pituophis catenifer sayi). In an attempt to determine which independent variables significantly affected the thermal ecology of free-ranging bullsnakes, we tracked 12–19 radio-tagged individuals weekly from 2003 to

J. M. Kapfer; M. J. Pauers; D. M. Reineke; J. R. Coggins; R. Hay

2008-01-01

181

Storage and Vase Life of Cut Rose Flowers as Influenced by Various Packing Materials  

Microsoft Academic Search

The influence of various packing materials, viz. cellophane paper, butter paper and aluminum lamination foil, on the storage and vase life of cut rose flowers (Rosa hybrida L. cvs. Kardinal, Gold Medal and Anjleeq) was studied. Flowers were harvested at two different stages, viz. tight bud stage and loose bud stage. Data regarding storage life (days) and vase life (days)

M. USMAN FAROOQ; IFTIKHAR AHMAD; M. ASLAM KHAN

182

Lymphocyte response to mitogens: influence of life events and personality.  

PubMed

The aim of the present study was to examine the possibility that the accumulation of life events is associated with low lymphoproliferative response to mitogens in undergraduate students. We also analyzed the possible interaction between life events and personality traits. Lymphocyte response to phytohemagglutinin (PHA) was lower in subjects with high life events compared to those with low levels. Introverted subjects were found to exhibit lower lymphocyte responses to PHA than those who were extraverted, and there was no interaction between the effect of introversion and life events on the proliferative capacity. Lymphocyte proliferation was low in subjects with high anxiety scores, whether they had high or low levels of life events. In the group with high scores on independence a high accumulation of life events was not associated with lower lymphoproliferation; while in the group with low scores it was, suggesting that independence buffers the association between life stress and lower cellular immunity. PMID:9732209

González-Quijano, M I; Martín, M; Millán, S; López-Calderón, A

1998-01-01

183

The influence of habitat, season and tidal regime in the activity of the intertidal crab Neohelice (= Chasmagnathus) granulata  

NASA Astrophysics Data System (ADS)

The activity pattern of intertidal crabs is influenced by factors that usually change rhythmically following tidal and/or diel cycles, and is often associated with the use of refuges. The movement activity of the burrowing crab Neohelice granulata was compared among three populations from SW Atlantic coastal areas where they face different tidal regimes, water salinities, substrata and biological factors. At each site, we examined the seasonal activity of the crabs (individuals collected in pitfall traps) in two types of habitat: mudflat and salt marsh. The working hypothesis is that the activity would vary according to the diverse environmental conditions encountered at geographical and local scales. Crab activity varied between sites and seasons showing to be more intense when habitats were covered by water. The most active groups were large males, followed by large non-ovigerous females. Ovigerous females were almost inactive. Most crabs were near or inside burrows at low tides in Mar Chiquita and Bahía Blanca, but they were active at both low and high tides in San Antonio during spring and summer. N. granulata were active in a wide range of temperatures: from 10 to 37 °C at low tides and at temperatures as low as 2 °C when covered by water. Differences of activity between mudflat and salt marsh varied among sites depending on flooding frequencies. Movement activity of N. granulata varied both in space and in time; crabs move under very different abiotic conditions (e.g., low or high tide, daylight or night, low and high temperature) and their movement may also be prevented or elicited by biotic conditions like burrow complexity, food quality and predation pressure. The wide set of conditions under which N. granulata can be active may explain why this is the only semiterrestrial crab inhabiting latitudes higher than 40°S in South America.

Luppi, Tomás; Bas, Claudia; Méndez Casariego, Agustina; Albano, Mariano; Lancia, Juan; Kittlein, Marcelo; Rosenthal, Alan; Farías, Nahuel; Spivak, Eduardo; Iribarne, Oscar

2013-03-01

184

Life on the Edge: Investigating Habitat Fragmentation, the Edge Effect and Associated Invasive Species in the Field  

NSDL National Science Digital Library

This field activity allows students to discover the impacts of habitat fragmentation on air and soil temperature, canopy cover, and invasive species presence. It is a versatile activity that can be conducted on a typical campus and modified based on resources available.

Sluss, Tamara

2011-03-02

185

The influence of nocturia on the quality of life  

Microsoft Academic Search

Background: Previous studies identified an effect of nocturia (two or more micturitions per night) on quality of life. We hypothesize that nocturia indeed affect quality of life but that effect is mediated via sleep. Nocturia and sleep disturbances are clearly associated. To go to the toilet one has to wake up. Lack of sleep is associated with mood disorders, depression

D. G. Kooij; L. van Dijk; F. Schellevis

2002-01-01

186

Influences of forest cover type and structure on seasonal and daily habitat use of wild turkeys in southern Georgia.  

E-print Network

??Information regarding wild turkey (Meleagris gallopavo) habitat use on northern bobwhite (Colinus virginianus) plantations in the Southeast is limited. These plantations are largely comprised of… (more)

Juhan, Steven Michael, Jr.

2006-01-01

187

Habitability: where lo look for life? Halophilic habitats: earth analogs to study Mars and Europá s habitability  

Microsoft Academic Search

Current Mars exploration is producing a considerable amount of information which requires comparison with terrestrial analogs in order to interpret and evaluate compatibility with possible extinct and\\/or extant life on the planet. The first astrobiological mission specially designed to detect life on Mars, the Viking missions, thought life unlikely, considering the amount of UV radiation bathing the surface of the

F. Gómez; J. Gómez-Elvira; N. Rodríguez; J. F. Caballero Castrejón; R. Amils; J. A. Rodríguez-Manfredi

2009-01-01

188

The Influence of Roads and Buffer Depth on Habitat Core Areas and Connectivity in the NE USA  

NASA Astrophysics Data System (ADS)

Land development pressures that threaten habitat core areas and connectivity are intensifying across the nation and extending beyond urbanized areas in the form of rural residential development. This is particularly true in the temperate forests of the northeastern U.S. If current trends continue, increased conversion and fragmentation of many roadless areas by exurban development is likely, exacerbating the likelihood of local species extinctions and complicating efforts to preserve intact functional ecosystems. We used a suite of nationally available data sets to identify roadless areas of the northeastern USA including impervious cover (urbanized and developed areas), road networks (and derived density), and forest cover (canopy density). We analyzed the influence of different types of unimproved roads and amount of forest cover on identification of the extent and configuration of roadless areas, and then assessed these areas in terms of land ownership (public, private) and management (parks, refuges, multi-use, etc.). We also derived patch connectivity metrics using a graph theory approach, making use of cost surfaces that accounted for the above variables and associated landscape metrics. Our results suggest a starting point for the construction of a more comprehensive and ecologically functional reserve network for the region. Because the data sets we used are available nationally, similar analyses could be conducted to assess the extent and status of roadless areas nationally or for other specific regions.

Jantz, P.; Goetz, S.

2006-12-01

189

The influence of habitats on female mobility in Central and Western Africa inferred from human mitochondrial variation  

PubMed Central

Background When studying the genetic structure of human populations, the role of cultural factors may be difficult to ascertain due to a lack of formal models. Linguistic diversity is a typical example of such a situation. Patrilocality, on the other hand, can be integrated into a biological framework, allowing the formulation of explicit working hypotheses. The present study is based on the assumption that patrilocal traditions make the hypervariable region I of the mtDNA a valuable tool for the exploration of migratory dynamics, offering the opportunity to explore the relationships between genetic and linguistic diversity. We studied 85 Niger-Congo-speaking patrilocal populations that cover regions from Senegal to Central African Republic. A total of 4175 individuals were included in the study. Results By combining a multivariate analysis aimed at investigating the population genetic structure, with a Bayesian approach used to test models and extent of migration, we were able to detect a stepping-stone migration model as the best descriptor of gene flow across the region, with the main discontinuities corresponding to forested areas. Conclusions Our analyses highlight an aspect of the influence of habitat variation on human genetic diversity that has yet to be understood. Rather than depending simply on geographic linear distances, patterns of female genetic variation vary substantially between savannah and rainforest environments. Our findings may be explained by the effects of recent gene flow constrained by environmental factors, which superimposes on a background shaped by pre-agricultural peopling. PMID:23360301

2013-01-01

190

Influence of Activity on Quality of Life Scores After RYGBP  

Microsoft Academic Search

Gastric bypass is one of the medically acceptable interventions for weight loss for the obese. Quality of life greatly improves\\u000a after surgery. Most improvements in quality of life (QOL) after these surgeries are attributed to the weight loss. Few studies\\u000a have demonstrated any contribution of other variables to positive outcomes in QOL. The purpose of this study was to suggest

Steven W. Forbush; Leah Nof; John Echternach; Cheryl Hill

2011-01-01

191

J. Seckbach (ed.), Genesis -In The Beginning: Precursors of Life, Chemical Models and Early Biological Evolution, Cellular Origin, Life in Extreme Habitats and Astrobiology 22, 799815  

E-print Network

of these features makes them the best candidates for being features of extraterrestrial life. Other frequently the other ingredients for life (Pizzarello, 2007). But is the universe filled with life? If it is, what kind a tiny subset barks at passing cars. From this we can infer that on other terrestrial planets, we

Lineweaver, Charles H.

192

Lunar/Mars Surface Habitat Mockups Project  

NASA Technical Reports Server (NTRS)

Surface habitats play a centric role with respect to integration of the crew operations and supporting surface systems for external operations on the moon and Mars. Up to now the only planetary surface habitat NASA has ever developed is the 2-person, 3-day duration Lunar Module from the 1960 s-era Apollo Program. Today s National Vision for Space Exploration pushes far beyond the safety, performance and operational requirements of the Lunar Module, and NASA needs to develop a basis for making habitat design decisions Experience has shown that using mockups very early in a project s life cycle is extremely beneficial, providing data that influences requirements for human design, volumetrics, functionality, systems hardware and operations. Evaluating and comparing a variety of habitat configurations will provide NASA with a cost-effective basis for trades to support lunar and Martian habitat design selection. This paper describes the NASA project that recently has been created to undertake the development and evaluation of a series of planetary surface habitat mockups. This project is in direct response to the Advanced Space Platforms and Systems (ASPS) Element Program s request for novel systems approaches for robust and reconfigurable habitation systems.

Tri, Terry O.; Daues, Katherine R.

2005-01-01

193

Liana habitat and host preferences in northern temperate forests  

Microsoft Academic Search

Lianas and other climbers are important ecological and structural components of forest communities. Like other plants, their abundance in a given habitat depends on a variety of factors, such as light, soil moisture and nutrients. However, since lianas require external support, host tree characteristics also influence their distribution. Lianas are conspicuous life forms in tropical regions, but in temperate areas,

Stacey A. Leicht-Young; Noel B. Pavlovic; Krystalynn J. Frohnapple; Ralph Grundel

2010-01-01

194

Influences of Wildfire, Habitat Size, and Connectivity on Trout in Headwater Streams Revealed by Patterns of Genetic Diversity  

Microsoft Academic Search

Wildfire is an important natural process in many stream ecosystems, but the ability of fish to respond to wildfire-related disturbances is increasingly constrained by human activities that fragment and degrade stream habitats. In this study, we used molecular genetic markers (nuclear microsatellites) to examine the effects of wildfire and related disturbances along with habitat fragmentation on native rainbow trout in

Helen Neville; Jason Dunham; Amanda Rosenberger; John Umek; Brooke Nelson

2009-01-01

195

Managing for Habitat Heterogeneity in Grassland Agro-Ecosystems Influences the Abundance of Masked Shrews (Sorex cinereus)  

Microsoft Academic Search

Many agri-environment programs prescribe modified farming practices and provision of heterogeneous habitat types, such as fallow field edges and shelterbelts. The conservation benefit of these actions to biodiversity has been well described. However, the response of insectivorous small mammals to habitat heterogeneity in agro-ecosystems has received little empirical attention. We compared the abundance of the masked shrew (Sorex cinereus) between

Joseph J. Nocera; Kimberly L. Dawe

2008-01-01

196

Influence of whitebark pine decline on fall habitat use and movements of grizzly bears in the Greater Yellowstone Ecosystem.  

PubMed

When abundant, seeds of the high-elevation whitebark pine (WBP; Pinus albicaulis) are an important fall food for grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem. Rates of bear mortality and bear/human conflicts have been inversely associated with WBP productivity. Recently, mountain pine beetles (Dendroctonus ponderosae) have killed many cone-producing WBP trees. We used fall (15 August-30 September) Global Positioning System locations from 89 bear years to investigate temporal changes in habitat use and movements during 2000-2011. We calculated Manly-Chesson (MC) indices for selectivity of WBP habitat and secure habitat (?500 m from roads and human developments), determined dates of WBP use, and documented net daily movement distances and activity radii. To evaluate temporal trends, we used regression, model selection, and candidate model sets consisting of annual WBP production, sex, and year. One-third of sampled grizzly bears had fall ranges with little or no mapped WBP habitat. Most other bears (72%) had a MC index above 0.5, indicating selection for WBP habitats. From 2000 to 2011, mean MC index decreased and median date of WBP use shifted about 1 week later. We detected no trends in movement indices over time. Outside of national parks, there was no correlation between the MC indices for WBP habitat and secure habitat, and most bears (78%) selected for secure habitat. Nonetheless, mean MC index for secure habitat decreased over the study period during years of good WBP productivity. The wide diet breadth and foraging plasticity of grizzly bears likely allowed them to adjust to declining WBP. Bears reduced use of WBP stands without increasing movement rates, suggesting they obtained alternative fall foods within their local surroundings. However, the reduction in mortality risk historically associated with use of secure, high-elevation WBP habitat may be diminishing for bears residing in multiple-use areas. PMID:24963393

Costello, Cecily M; van Manen, Frank T; Haroldson, Mark A; Ebinger, Michael R; Cain, Steven L; Gunther, Kerry A; Bjornlie, Daniel D

2014-05-01

197

Influence of whitebark pine decline on fall habitat use and movements of grizzly bears in the Greater Yellowstone Ecosystem  

PubMed Central

When abundant, seeds of the high-elevation whitebark pine (WBP; Pinus albicaulis) are an important fall food for grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem. Rates of bear mortality and bear/human conflicts have been inversely associated with WBP productivity. Recently, mountain pine beetles (Dendroctonus ponderosae) have killed many cone-producing WBP trees. We used fall (15 August–30 September) Global Positioning System locations from 89 bear years to investigate temporal changes in habitat use and movements during 2000–2011. We calculated Manly–Chesson (MC) indices for selectivity of WBP habitat and secure habitat (?500 m from roads and human developments), determined dates of WBP use, and documented net daily movement distances and activity radii. To evaluate temporal trends, we used regression, model selection, and candidate model sets consisting of annual WBP production, sex, and year. One-third of sampled grizzly bears had fall ranges with little or no mapped WBP habitat. Most other bears (72%) had a MC index above 0.5, indicating selection for WBP habitats. From 2000 to 2011, mean MC index decreased and median date of WBP use shifted about 1 week later. We detected no trends in movement indices over time. Outside of national parks, there was no correlation between the MC indices for WBP habitat and secure habitat, and most bears (78%) selected for secure habitat. Nonetheless, mean MC index for secure habitat decreased over the study period during years of good WBP productivity. The wide diet breadth and foraging plasticity of grizzly bears likely allowed them to adjust to declining WBP. Bears reduced use of WBP stands without increasing movement rates, suggesting they obtained alternative fall foods within their local surroundings. However, the reduction in mortality risk historically associated with use of secure, high-elevation WBP habitat may be diminishing for bears residing in multiple-use areas. PMID:24963393

Costello, Cecily M; van Manen, Frank T; Haroldson, Mark A; Ebinger, Michael R; Cain, Steven L; Gunther, Kerry A; Bjornlie, Daniel D

2014-01-01

198

Can environmental conditions experienced in early life influence future generations?  

PubMed Central

The consequences of early developmental conditions for performance in later life are now subjected to convergent interest from many different biological sub-disciplines. However, striking data, largely from the biomedical literature, show that environmental effects experienced even before conception can be transmissible to subsequent generations. Here, we review the growing evidence from natural systems for these cross-generational effects of early life conditions, showing that they can be generated by diverse environmental stressors, affect offspring in many ways and can be transmitted directly or indirectly by both parental lines for several generations. In doing so, we emphasize why early life might be so sensitive to the transmission of environmentally induced effects across generations. We also summarize recent theoretical advancements within the field of developmental plasticity, and discuss how parents might assemble different ‘internal’ and ‘external’ cues, even from the earliest stages of life, to instruct their investment decisions in offspring. In doing so, we provide a preliminary framework within the context of adaptive plasticity for understanding inter-generational phenomena that arise from early life conditions. PMID:24807254

Burton, Tim; Metcalfe, Neil B.

2014-01-01

199

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...

200

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

201

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

202

Genetic and Environmental Influences on Life History Traits in Lake Trout  

Microsoft Academic Search

Lake trout Salvelinus namaycush exhibit substantial life history variation associated with variation in climatic and biotic variables. To assess the environmental and genetic influences on lake trout life history traits, eggs were collected from two lakes in Algonquin Park, Ontario, Lake Opeongo and Louisa Lake, with contrasting ecotypes and forage bases. Eggs from both populations and interpopulation hybrids (Lake Opeongo

Jenni L. McDermid; Peter E. Ihssen; William N. Sloan; Brian J. Shuter

2007-01-01

203

Prestraining and Its Influence on Subsequent Fatigue Life  

NASA Technical Reports Server (NTRS)

An experimental program was conducted to study the damaging effects of tensile and compressive prestrains on the fatigue life of nickel-base, Inconel 718 superalloy at room temperature. To establish baseline fatigue behavior, virgin specimens with a solid uniform gage section were fatigued to failure under fully-reversed strain-control. Additional specimens were prestrained to 2 percent, 5 percent, and 10 percent (engineering strains) in the tensile direction and to 2 percent (engineering strain) in the compressive direction under stroke-control, and were subsequently fatigued to failure under fully-reversed strain-control. Experimental results are compared with estimates of remaining fatigue lives (after prestraining) using three life prediction approaches: (1) the Linear Damage Rule; (2) the Linear Strain and Life Fraction Rule; and (3) the nonlinear Damage Curve Approach. The Smith-Watson-Topper parameter was used to estimate fatigue lives in the presence of mean stresses. Among the cumulative damage rules investigated, best remaining fatigue life predictions were obtained with the nonlinear Damage Curve Approach.

Halford, Gary R.; Mcgaw, Michael A.; Kalluri, Sreeramesh

1995-01-01

204

Prestraining and its influence on subsequent fatigue life  

NASA Technical Reports Server (NTRS)

An experimental program was conducted to study the damaging effects of tensile and compressive prestrains on the fatigue life of nickel-base, Inconel 718 superalloy at room temperature. To establish baseline fatigue behavior, virgin specimens with a solid uniform gage section were fatigued to failure under fully-reversed strain-control. Additional specimens were prestrained to 2 percent, 5 percent, and 10 percent (engineering strains) in the tensile direction and to 2 percent (engineering strain) in the compressive direction under stroke-control, and were subsequently fatigued to failure under fully-reversed strain-control. Experimental results are compared with estimates of remaining fatigue lives (after prestraining) using three life prediction approaches: (1) the Linear Damage Rule; (2) the Linear Strain and Life Fraction Rule; and (3) the nonlinear Damage Curve Approach. The Smith-Watson-Topper parameter was used to estimate fatigue lives in the presence of mean stresses. Among the cumulative damage rules investigated, best remaining fatigue life predictions were obtained with the nonlinear Damage Curve Approach.

Halford, Gary R.; Mcgaw, Michael A.; Kalluri, Sreeramesh

1995-01-01

205

Ribbon of Life: An Agenda for Preserving Transboundary Migratory Bird Habitat on the Upper San Pedro River  

NSDL National Science Digital Library

The Commission for Environmental Cooperation (CEC) has released this report "to foster cooperative efforts to ensure the continued health of the San Pedro Watershed." Over the past century, the ecological integrity of the Upper San Pedro River has declined substantially; the loss of riparian habitat has important implications for migratory birds. The report (.pdf format), which may be downloaded at the site, calls for coordinated management of the watershed, further research in certain key areas, greater collaboration among stakeholders, and increased public education efforts.

206

Niche Habitats for ExtraTerrestrial Life: The Potential for Astrobiology on the Moons of Saturn and Jupiter  

Microsoft Academic Search

Astrobiology today has a strong anticipatory focus, and efforts are concentrated on determining the factors behind the potential presence, type, and distribution of life in our solar system and beyond. The critical requirements for life: a liquid solvent, and electron acceptors and donors for metabolism, guide the search, and is a central concept to the location and extent of circumstellar

Leila Battison

2011-01-01

207

INFLUENCE OF STREAM NETWORK-SCALE HABITAT OF A COASTAL OREGON WATERSHED ON COHO SALMON AND OTHER NATIVE FISH  

EPA Science Inventory

EPA's Western Ecology Division is undertaking research addressing catchment-scale dynamics of freshwater habitat productivity for native fishes. Through partnerships with state and federal agencies and private landowners, current field efforts focus on linkages among stream chemi...

208

Influence of surface roughness skewness on rolling contact fatigue life  

NASA Astrophysics Data System (ADS)

This paper evaluates the effects of randomly distributed small indentations, or pits, on the lubricating properties when operating under these mixed or boundary lubrication conditions. Rings and needle rollers were textured with randomly distributed small indentations, or pits, for evaluation. Skewness (Sk) was used as a measure of surface finish to characterize the degree to which the material of these modified parts was above the mean line, a positive value, or below the mean line, a negative value. Fatigue life tests were conducted on these rolling elements, whose skewness ranged from -1.2 to -2.0, under mixed or boundary lubrication conditions. Test results showed rolling bearing fatigue life to increase with a decrease in skewness as related to the depth, width, and distribution of the surface indentations, or pits, on the parts.

Akamatsu, Yoshinobu; Tsushima, Noriyuki; Goto, Toshihide; Hibi, Kenji

1992-10-01

209

Global undernutrition during gestation influences learning during adult life  

Microsoft Academic Search

Intrauterine growth restriction can lead to significant long-term health consequences such as metabolic and cardiovascular\\u000a disorders, but less is known about its effects on choice and behavioral adaptation in later life. Virgin Wistar rats were\\u000a time mated and randomly assigned to receive either ad-libitum access to chow or 30% of that level of nutrition during pregnancy\\u000a to generate growth-restricted offspring.

Jason Landon; Michael Davison; Christian U. Krägeloh; Nichola M. Thompson; Jennifer L. Miles; Mark H. Vickers; Mhoyra Fraser; Bernhard H. Breier

2007-01-01

210

The historic influence of dams on diadromous fish habitat with a focus on river herring and hydrologic longitudinal connectivity  

Microsoft Academic Search

The erection of dams alters habitat and longitudinal stream connectivity for migratory diadromous and potamodromous fish species\\u000a and interrupts much of organismal exchange between freshwater and marine ecosystems. In the US, this disruption began with\\u000a colonial settlement in the seventeenth century but little quantitative assessment of historical impact on accessible habitat\\u000a and population size has been conducted. We used published

Carolyn J. Hall; Adrian Jordaan; Michael G. Frisk

2011-01-01

211

Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts.  

PubMed

Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using (14)CO2) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them. PMID:24694713

Colesie, Claudia; Allan Green, T G; Haferkamp, Ilka; Büdel, Burkhard

2014-10-01

212

[Influence of permafrost microorganisms on the quality and duration of life of laboratory animals].  

PubMed

Microorganisms of genus Bacillus strain 3M (permafrost microorganisms--PM), allocated from the samples of permafrost soils from Mamontova Mountain (Yakutia) are influenced by the quality and duration of life of elderly mice. PMs were injected intraperitoneally to CBA mice at the age of 17 months. Motion activity, muscular force (lifting of cargo test), food instinct activity (dosed starvation test) and cellular immunity activity (reaction of delayed-type hypersensitivity in vivo) of animals have increased, and psychoemotional condition of animals has improved under influence of PM. Average duration of life has increased by 9.19%, minimal duration of life--by 41.93%, maximal duration of life--by 7.68%. Duration of survival (the remaining life after injection of microorganisms) has increased more significantly: minimal--by 141.9%, on the average--by 28.0%, maximal--by 20.4%. Mechanisms of PM influence on increase of laboratory mice duration of life up to the top specific limit through the positive influence on quality of their life are discussed. PMID:20297696

Kalenova, L F; Sukhove?, Iu G; Brushkov, A V; Mel'nikov, V P; Fisher, T A; Besedin, I M; Novikova, M A; Efimova, Iu A

2010-01-01

213

Estuarine Habitats for Juvenile Salmon in the Tidally-Influenced Lower Columbia River and Estuary : Reporting Period September 15, 2008 through May 31, 2009.  

SciTech Connect

This work focuses on the numerical modeling of Columbia River estuarine circulation and associated modeling-supported analyses conducted as an integral part of a multi-disciplinary and multi-institutional effort led by NOAA's Northwest Fisheries Science Center. The overall effort is aimed at: (1) retrospective analyses to reconstruct historic bathymetric features and assess effects of climate and river flow on the extent and distribution of shallow water, wetland and tidal-floodplain habitats; (2) computer simulations using a 3-dimensional numerical model to evaluate the sensitivity of salmon rearing opportunities to various historical modifications affecting the estuary (including channel changes, flow regulation, and diking of tidal wetlands and floodplains); (3) observational studies of present and historic food web sources supporting selected life histories of juvenile salmon as determined by stable isotope, microchemistry, and parasitology techniques; and (4) experimental studies in Grays River in collaboration with Columbia River Estuary Study Taskforce (CREST) and the Columbia Land Trust (CLT) to assess effects of multiple tidal wetland restoration projects on various life histories of juvenile salmon and to compare responses to observed habitat-use patterns in the mainstem estuary. From the above observations, experiments, and additional modeling simulations, the effort will also (5) examine effects of alternative flow-management and habitat-restoration scenarios on habitat opportunity and the estuary's productive capacity for juvenile salmon. The underlying modeling system is part of the SATURN1coastal-margin observatory [1]. SATURN relies on 3D numerical models [2, 3] to systematically simulate and understand baroclinic circulation in the Columbia River estuary-plume-shelf system [4-7] (Fig. 1). Multi-year simulation databases of circulation are produced as an integral part of SATURN, and have multiple applications in understanding estuary/plume variability, the role of the estuary and plume on salmon survival, and functional changes in the estuary-plume system in response to climate and human activities.

Baptista, António M. [Oregon Health & Science University, Science and Technology Center for Coastal Margin Observation and Prediction

2009-08-02

214

Collective emotions online and their influence on community life  

E-print Network

E-communities, social groups interacting online, have recently become an object of interdisciplinary research. As with face-to-face meetings, Internet exchanges may not only include factual information but also emotional information - how participants feel about the subject discussed or other group members. Emotions are known to be important in affecting interaction partners in offline communication in many ways. Could emotions in Internet exchanges affect others and systematically influence quantitative and qualitative aspects of the trajectory of e-communities? The development of automatic sentiment analysis has made large scale emotion detection and analysis possible using text messages collected from the web. It is not clear if emotions in e-communities primarily derive from individual group members' personalities or if they result from intra-group interactions, and whether they influence group activities. We show the collective character of affective phenomena on a large scale as observed in 4 million po...

Chmiel, Anna; Thelwall, Mike; Paltoglou, Georgios; Buckley, Kevan; Kappas, Arvid; Ho?yst, Janusz A

2011-01-01

215

Habitability: where lo look for life? Halophilic habitats: earth analogs to study Mars and Europá s habitability  

NASA Astrophysics Data System (ADS)

Current Mars exploration is producing a considerable amount of information which requires comparison with terrestrial analogs in order to interpret and evaluate compatibility with possible extinct and/or extant life on the planet. The first astrobiological mission specially designed to detect life on Mars, the Viking missions, thought life unlikely, considering the amount of UV radiation bathing the surface of the planet, the resulting oxidative conditions, and the lack of adequate atmospheric protection. The necessity of the Europa surface exploration comes from the idea of a water ocean existence in its interior. Europa surface presents evidence of an active geology showing many tectonic features that seems to be connected with some liquid interior reservoir. Life needs several requirements for its establishment but, the only sine qua nom elements is the water, taking into account our experience on Earth extreme ecosystems The discovery of extremophiles on Earth widened the window of possibilities for life to develop in the universe, and as a consequence on Mars. The compilation of data produced by the ongoing missions (Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Exploration Rover Opportunity) offers a completely different view: signs of an early wet Mars and rather recent volcanic activity. The discovery of important accumulations of sulfates, and the existence of iron minerals like jarosite, goethite and hematite in rocks of sedimentary origin has allowed specific terrestrial models related with this type of mineralogy to come into focus. Río Tinto (Southwestern Spain, Iberian Pyritic Belt) is an extreme acidic environment, product of the chemolithotrophic activity of microorganisms that thrive in the massive pyrite-rich deposits of the Iberian Pyritic Belt. The high concentrations of ferric iron and sulfates, products of the metabolism of pyrite, generate a collection of minerals, mainly gypsum, jarosite, goethite and hematites, all of which have been detected in different regions of Mars (Fernández-Remolar et al., 2004). But, where to look for life in other planetary bodies? Planet's or Icy Moon`s surface are adverse for life. Harsh conditions for life to wheal with. Similar harsh conditions as the primordial Earth ones during the time when origin of life occurred. In the last case, life was originated under high irradiation conditions, meteorite bombardment and high temperature. Some particular protective environments or elements should house the organic molecules and the first bacterial life forms (Gómez F. et al., 2007). Terrestrial analogues work could help us to afford its comprehension. We are reporting here some preliminary studies about endolithic niches inside salt deposits used by phototrophs for taking advantage of sheltering particular light wavelengths. These acidic salts deposits located in Río Tinto shelter life forms which are difficult to localize by eye. Molecular ecology techniques are needed for its localization and study. Bibliography Fernández-Remolar, D., Gómez-Elvira, J., Gómez, F., Sebastián, E., Martín, J., Manfredi, J.A., Torres, J., González Kesler, C. and Amils, R. Planetary and Space Science 52 (2004) 239 - 248 Gómez, F., Aguilera, A. and Amils, R. Icarus 191 (2007) 352-359. Acknowledgments This study was funded by the project ESP2006-06640 from Spanish Ministry of Education and Science and FEDER funds from European Community.

Gómez, F.; Gómez-Elvira, J.; Rodríguez, N.; Caballero Castrejón, J. F.; Amils, R.; Rodríguez-Manfredi, J. A.

2009-04-01

216

Neighborhood Influences on Late Life Cognition in the ACTIVE Study  

PubMed Central

Low neighborhood-level socioeconomic status has been associated with poorer health, reduced physical activity, increased psychological stress, and less neighborhood-based social support. These outcomes are correlates of late life cognition, but few studies have specifically investigated the neighborhood as a unique source of explanatory variance in cognitive aging. This study supplemented baseline cognitive data from the ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly) study with neighborhood-level data to investigate (1) whether neighborhood socioeconomic position (SEP) predicts cognitive level, and if so, whether it differentially predicts performance in general and specific domains of cognition and (2) whether neighborhood SEP predicts differences in response to short-term cognitive intervention for memory, reasoning, or processing speed. Neighborhood SEP positively predicted vocabulary, but did not predict other general or specific measures of cognitive level, and did not predict individual differences in response to cognitive intervention. PMID:22966458

Sisco, Shannon M.; Marsiske, Michael

2012-01-01

217

Genetic and Environmental Influences on Negative Life Events From Late Childhood to Adolescence  

PubMed Central

This multi-wave longitudinal study tested two quantitative genetic developmental models to examine genetic and environmental influences on exposure to negative dependent and independent life events. Participants (N = 457 twin pairs) completed measures of life events annually from ages 9 to 16. The same genetic factors influenced exposure to dependent events across time, and increased in magnitude during the transition to adolescence. Independent events were less genetically influenced than dependent events in boys, but not girls. Shared environmental influences decreased in magnitude as youth transitioned into adolescence. Nonshared environmental influences were mostly age-specific and contributed significantly to both types of events at all ages. Results provide theoretical implications for developmental risk pathways to stress exposure and stress-related psychopathology. PMID:23379294

Johnson, Daniel P.; Rhee, Soo Hyun; Whisman, Mark A.; Corley, Robin P.; Hewitt, John K.

2012-01-01

218

A study of air pollutants influencing life expectancy and longevity from spatial perspective in China.  

PubMed

Life expectancy and longevity are influenced by air pollutants and socioeconomic status, but the extend and significance are still unclear. Better understanding how the spatial differences of life expectancy and longevity are affected by air pollutants is needed for generating public health and environmental strategies since the whole of China is now threatened by deteriorated air quality. 85 major city regions were chosen as research areas. Geographically Weighted Regression (GWR) and Stepwise Regression (SR) were used to find the spatial correlations between health indicators and air pollutants, adjusted by per capita GDP(1). The results were, regions with higher life expectancy were mainly located in the east area and areas with good air quality, a regional difference of 10 ?g/m(3) in ambient air SO2(2) could cause adjusted 0.28 year's difference in life expectancy, a regional difference of 10 ?g/m(3) in ambient air PM10(3) could lead to a longevity ratio difference of 2.23, and per capita GDP was positively associating with life expectancy but not longevity ratio, with a regional difference of 10,000 RMB(4) associating with adjusted 0.49 year's difference in life expectancy. This research also showed the evidences that there exist spatially differences for ambient air PM10 and SO2 influencing life expectancy and longevity in China, and this influences were clearer in south China. PMID:24768912

Wang, Li; BingganWei; Li, Yonghua; Li, Hairong; Zhang, Fengying; Rosenberg, Mark; Yang, Linsheng; Huang, Jixia; Krafft, Thomas; Wang, Wuyi

2014-07-15

219

Individual Variation in Life History Characteristics Can Influence Extinction Risk  

SciTech Connect

The white sturgeon (Acipenser transmontanus) shows great individual variation in the age at maturation. This study examines the consequences of model assumptions about individual variation in the age at maturation on predicted population viability. I considered: (1) the effects of variation in age at maturation alone; (2) the effects of heritability; and (3) the influence of a stable and an altered selective regime. Two selective regimes represented conditions before and after the impoundment of a river, blocking access of anadromous white sturgeon populations to the ocean. In contrast to previous simulation studies, I found that increased individual variation in the age at maturity did not necessarily lead to a higher likelihood of persistence. Individual variation increased the simulated likelihood of persistence when the variation was heritable and the selective regime had changed such that the mean age at maturity was no longer optimal.

Jager, H.I.

2001-01-01

220

Influence of life-history variation on the genetic structure of two sympatric salamander taxa  

Microsoft Academic Search

Life-history characteristics are an important determinant of a species' dispersal abilities. We predict that variation in life history can influence population-level genetic patterns. To test this prediction, we estimate population-level genetic structure for two sympatric species of stream-breeding salamander. The Cope's giant salamander (Dicamptodon copei) rarely metamorphoses into a terrestrial adult, thereby limiting overland dispersal and potentially gene flow. In

C. A. STEELE; J. BAUMSTEIGER; ANDREW STORFER

2009-01-01

221

Field ecology of a brood-caring dung beetle Kheper nigroaeneus habitat predictability and life history strategy  

Microsoft Academic Search

Summary  The life history strategy of the dung beetleKheper nigroaeneus was studied in Mkuzi Game Reserve, South Africa.K. nigroaeneus, a large ball-rolling dung beetle, brood-cares a single offspring per nesting occasion. Adults emerged from the ground following\\u000a the first spring rain (?17 mm) in October or November, occasionally September, and trap catches were at a maximum 1–2 weeks\\u000a later. Females outnumbered

Penelope B. Edwards

1988-01-01

222

Multi-scale patterns of habitat use by Roanoke logperch (Percina rex) in Virginia rivers: a comparison among populations and life stages.  

E-print Network

Multi-scale patterns of habitat use by Roanoke logperch (Percina rex) in Virginia rivers: Percina rex, habitat use, model transferability, ontogeny, spatial scale, endangered species Copyright 2002, Amanda Rosenberger #12;Multi-scale patterns of habitat use by Roanoke logperch (Percina rex

223

The influence of habitat, prey abundance, sex, and breeding success on the ranging behavior of Prairie Falcons  

USGS Publications Warehouse

We studied the ranging behavior and habitat selection of radio-tagged Prairie Falcons (Falco mexicanus) during the breeding season in southwestern Idaho. The distribution and numbers of Townsend's ground squirrels (Spermophilus townsendii), the primary prey of Prairie Falcons in our study area, varied in response to drought during the study period. Prairie Falcons ranged over large areas (ca. 300 km2) and increased their foraging ranges in response to declining ground squirrels. Reptiles and birds were preyed upon most frequently when squirrels were rare. Males and females differed little in their use of space. Successful pairs ranged over smaller areas than non-nesters and unsuccessful pairs. Falcons nesting near habitat most suitable for ground squirrels ranged over smaller areas than those nesting farther from such habitat. Home ranges contained significantly more winterfat (Ceratoides lanata) and native perennial grasses (especially Poa secunda), and significantly less salt desert shrubs and exotic annual grasses than expected based on availability. Salt desert shrubs were found less than expected, based on availability in core areas within home ranges. Selection for winterfat and bluegrass in core areas was contingent upon selection at the larger scale of the home range; falcons with home ranges containing more winterfat and bluegrass than expected based on availability were less selective in their placement of core areas with respect to these habitats. We believe salient features of Prairie Falcon home ranges result largely from patchy distribution of landscape features associated with different densities and availabilities of Townsend's ground squirrels.

Marzluff, J.M.; Kimsey, Bryan A.; Schueck, Linda S.; McFadzen, Mary E.; Vekasy, M.S.; Bednarz, James C.

1997-01-01

224

Local Habitat, Watershed, and Biotic Factors Influencing the Spread of Hybridization between Native Westslope Cutthroat Trout and Introduced Rainbow Trout  

Microsoft Academic Search

The invasion of nonnative fishes in freshwater systems is often facilitated by the interaction of biotic and abiotic factors operating at multiple spatial and temporal scales. We evaluated the association of local habitat features (width, gradient, and elevation), watershed characteristics (mean and maximum summer water temperatures, the number of road crossings, and road density), and biotic factors (the distance to

Clint C. Muhlfeld; Thomas E. McMahon; Matthew C. Boyer; Robert E. Gresswell

2009-01-01

225

Basic and Applied Ecology 12 (2011) 654663 Seasonal shifts in habitat selection of a large herbivore and the influence  

E-print Network

(APP), Ontario, Canada, to those of 14 adult females located in provincial Wildlife Management Unit (WMU) 49, 40 km west of the protected area. Wildlife and habitat management practices differed between management strategies between areas and ensuing differences in predation and hunting mortality risk

226

Longitudinal variation and habitat associations of small fishes in the Bighorn River, Wyoming: influences of river regulation and introduced fishes  

Microsoft Academic Search

We assessed variation in longitudinal distributions of native and introduced fishes and their occurrences in different habitat types downstream from Boysen Dam in the Bighorn River, Wyoming. The closure of Boysen Dam in 1952 and construction of three downstream water diversion dams have led to channel changes in the Bighorn River causing reductions in the numbers and areas of side

Jerry W. Wilhite; Wayne A. Hubert

2011-01-01

227

Physical factors and their influence on the mussel fauna of a main channel border habitat of the upper Mississippi River  

USGS Publications Warehouse

The habitats of mussel species in a portion of the main stem of Navigation Pool 10 of the upper Mississippi River were examined. Population composition, abundance, and sediment and current preferences were measured at 186 sites in the East Channel of the pool. Although total mussel abundance varied significantly as a function of sediment and current (p less than or equal to 0.05), abundance could be predicted in only 44% of sites by discriminant analysis models. Accurate prediction of abundance for most species also was poor. Species showed little discrimination in choosing main channel habitats, but could be broadly classified into species preferring fine to medium-fine sands (e.g., Truncilla truncata and Potamilus alatus) or coarser sands (e.g., Lampsilis cardium and Truncilla donaciformis). The endangered Lampsilis higginsi was found in a broad range of habitats similar to those occupied by many of the more common species, suggesting factors other than loss of adult habitat for the rarity of this species.

Holland Bartels, L. E.

1990-01-01

228

Plant epiphytism in semiarid conditions revealed the influence of habitat and climate variables on AM fungi communities distribution  

NASA Astrophysics Data System (ADS)

In semiarid Mediterranean ecosystems epiphytic plant species are practically absent and only some species of palm-trees can support epiphytes growing in their lower crown area, such as Phoenix dactylifera L. (date palm). In this study we focused in Sonchus tenerrimus L. plants growing as facultative epiphytes in P. dactylifera and its terrestrial forms growing in adjacent soils, Our aim was to determine the possible presence of AMF in these peculiar habitats and to relate AMF communities with climatic variations. We investigated the AMF community composition of epiphytic and terrestrial S. tenerrimus plants along a temperature and precipitation gradient across 12 localities. Epiphytic roots were colonized by AM fungi as determined by microscopic observation, all epiphytic and terrestrial samples analysed showed AMF sequences from taxa belonging to the phylum Glomeromycota, which were grouped in 30 AMF OTUs. The AMF community composition was clearly different between epiphytic and terrestrial root samples and this could be attributable to dispersal constraints and/or the contrasting environmental and ecophysiological conditions prevailing in each habitat. Across sites, the richness and diversity of terrestrial AMF communities was positively correlated with rainfall amount during the most recent growing season. In contrast, there was no significant correlation between climate variables and AMF richness and diversity for epiphytic AMF communities, which suggests that the composition of AMF communities in epiphytic habitats appears to be largely determined by the availability and dispersion of fungal propagules from adjacent terrestrial habitats.

Torrecillas, Emma; Torres, Pilar; Díaz, Gisela; del Mar Alguacil, Maria; Querejeta, Jose Ignacio; García, Fuensanta; Roldán, Antonio

2014-05-01

229

Early Life Stress as an Influence on Limbic Epilepsy: An Hypothesis Whose Time has Come?  

PubMed Central

The pathogenesis of mesial temporal lobe epilepsy (MTLE), the most prevalent form of refractory focal epilepsy in adults, is thought to begin in early life, even though seizures may not commence until adolescence or adulthood. Amongst the range of early life factors implicated in MTLE causation (febrile seizures, traumatic brain injury, etc.), stress may be one important contributor. Early life stress is an a priori agent deserving study because of the large amount of neuroscientific data showing enduring effects on structure and function in hippocampus and amygdala, the key structures involved in MTLE. An emerging body of evidence directly tests hypotheses concerning early life stress and limbic epilepsy: early life stressors, such as maternal separation, have been shown to aggravate epileptogenesis in both status epilepticus and kindling models of limbic epilepsy. In addition to elucidating its influence on limbic epileptogenesis itself, the study of early life stress has the potential to shed light on the psychiatric disorder that accompanies MTLE. For many years, psychiatric comorbidity was viewed as an effect of epilepsy, mediated psychologically and/or neurobiologically. An alternative – or complementary – perspective is that of shared causation. Early life stress, implicated in the pathogenesis of several psychiatric disorders, may be one such causal factor. This paper aims to critically review the body of experimental evidence linking early life stress and epilepsy; to discuss the direct studies examining early life stress effects in current models of limbic seizures/epilepsy; and to suggest priorities for future research. PMID:19838325

Koe, Amelia S.; Jones, Nigel C.; Salzberg, Michael R.

2009-01-01

230

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

231

Behavioral mechanisms of habitat segregation between sympatric species of Microtus : Habitat preference and interspecific dominance  

Microsoft Academic Search

Two species of microtine rodents are sympatric in eastern Washington, but they are segregated by habitat. Microtus montanus is found in the grass, and M. longicaudus occupies the shrub habitat. This investigation evaluated behavioral mechanisms controlling the distribution and asked the questions: (1) Are voles of either or both species occupying a preferred habitat? (2) Is a habitat preference influenced

Jan A. Randall

1978-01-01

232

Late-life depression and mortality: influence of gender and antidepressant use  

E-print Network

Late-life depression and mortality: influence of gender and antidepressant use JOANNE RYAN The British Journal of Psychiatry 2008;192:12-8 #12;Background: Depression may increase the risk of mortality at risk of dying, as a function of depressive symptoms, gender and antidepressant use. Method: Adjusted

233

Influence of Life Stress on Depression: Moderation by a Polymorphism in the 5-HTT Gene  

Microsoft Academic Search

In a prospective-longitudinal study of a representative birth cohort, we tested why stressful experiences lead to depression in some people but not in others. A functional polymorphism in the promoter region of the serotonin transporter (5-HTT) gene was found to moderate the influence of stressful life events on depression. Individuals with one or two copies of the short allele of

Avshalom Caspi; Karen Sugden; Terrie E. Moffitt; Alan Taylor; Ian W. Craig; HonaLee Harrington; Joseph McClay; Jonathan Mill; Judy Martin; Antony Braithwaite; Richie Poulton

2003-01-01

234

Late life depression and incident activity limitations: influence of gender and symptom Isabelle Carrirea,b,*  

E-print Network

1 Late life depression and incident activity limitations: influence of gender and symptom severity Background Mental disorders, especially depression, are one of the principal causes of disablement. Previous baseline depressive symptomatology and activity limitations were examined in a community-dwelling elderly

Paris-Sud XI, Université de

235

The Life Skills Program IPSY: Positive Influences on School Bonding and Prevention of Substance Misuse  

ERIC Educational Resources Information Center

The present study investigated whether a life skills program (LSP) for the prevention of adolescent substance misuse can have positive influences on a school context and on school bonding. The study also explored whether effects on alcohol use are mediated by positive effects on school bonding resulting from program participation. The LSP IPSY…

Wenzel, Victoria; Weichold, Karina; Silbereisen, Rainer K.

2009-01-01

236

The Influence of Western Society's Construction of a Healthy Daily Life on the Conceptualisation of Occupation  

Microsoft Academic Search

This article proposes that the current conceptualisation of occupation within the dominant Anglophone literature reflects central elements of Western society's construction of a ‘healthy’ daily life, the ‘ideal’ and expected way to live. Contemporary theories of social action are used to describe the structuring influence of social institutions on daily activity. Four of the commonly identified characteristics of occupation, that

Sarah Kantartzis; Matthew Molineux

2011-01-01

237

Life-course influences on nonearnings income migration in the United States  

Microsoft Academic Search

This paper contributes to the emerging body of literature examining the interregional income migration in the United States and offers explanations for why certain areas emerge as magnets for nonearnings income flows while other areas are losing this increasingly important source of personal income. By synthesizing ideas from contemporary understandings of life-course influences on migration and earlier work on income

Peter B Nelson

2008-01-01

238

The Influence of Life Roles and Readiness for Career Decision Making: The Case of Fabian.  

ERIC Educational Resources Information Center

Discusses case study of Fabian, nontraditional college student who sought assistance at university counseling center in choosing a career path. Looks at influence of life roles, conceptualizes case using Super's Model of Readiness for Career Decision Making, identifies missing information, and suggests career counseling interventions. (NB)

Niles, Spencer G.

1989-01-01

239

Factors Influencing Quality of Life of Hungarian Postmenopausal Women Screened by Osteodensitometry  

ERIC Educational Resources Information Center

The aim of our study was to evaluate factors influencing health related quality of life in Hungarian postmenopausal women who underwent osteodensitometry. A questionnaire-based cross-sectional study was carried out; 359 women aged over 40 years were involved, attending the outpatient Bone Densitometry Centre of Szeged. Two kinds of tools were…

Maroti-Nagy, Agnes; Paulik, Edit

2011-01-01

240

Family and television influences on materialism: a cross-cultural life-course approach  

Microsoft Academic Search

Purpose – The purpose of this study is to examine whether the development of materialistic values in early life reflects cultural norms or is the outcome of media and family influences. It seeks to examine the role of family communication and television, which were found to promote materialistic values in individualistic countries, by assessing their effects on youths in four

George Moschis; Fon Sim Ong; Anil Mathur; Takako Yamashita; Sarah Benmoyal-Bouzaglo

2011-01-01

241

Wetlands in Changed Landscapes: The Influence of Habitat Transformation on the Physico-Chemistry of Temporary Depression Wetlands  

PubMed Central

Temporary wetlands dominate the wet season landscape of temperate, semi-arid and arid regions, yet, other than their direct loss to development and agriculture, little information exists on how remaining wetlands have been altered by anthropogenic conversion of surrounding landscapes. This study investigates relationships between the extent and type of habitat transformation around temporary wetlands and their water column physico-chemical characteristics. A set of 90 isolated depression wetlands (seasonally inundated) occurring on coastal plains of the south-western Cape mediterranean-climate region of South Africa was sampled during the winter/spring wet season of 2007. Wetlands were sampled across habitat transformation gradients according to the areal cover of agriculture, urban development and alien invasive vegetation within 100 and 500 m radii of each wetland edge. We hypothesized that the principal drivers of physico-chemical conditions in these wetlands (e.g. soil properties, basin morphology) are altered by habitat transformation. Multivariate multiple regression analyses (distance-based Redundancy Analysis) indicated significant associations between wetland physico-chemistry and habitat transformation (overall transformation within 100 and 500 m, alien vegetation cover within 100 and 500 m, urban cover within 100 m); although for significant regressions the amount of variation explained was very low (range: ?2 to ?5.5%), relative to that explained by purely spatio-temporal factors (range: ?35.5 to ?43%). The nature of the relationships between each type of transformation in the landscape and individual physico-chemical variables in wetlands were further explored with univariate multiple regressions. Results suggest that conservation of relatively narrow (?100 m) buffer strips around temporary wetlands is likely to be effective in the maintenance of natural conditions in terms of physico-chemical water quality. PMID:24533161

Bird, Matthew S.; Day, Jenny A.

2014-01-01

242

Habitat Fragmentation and Ecological Traits Influence the Prevalence of Avian Blood Parasites in a Tropical Rainforest Landscape  

PubMed Central

In the tropical rainforests of northern Australia, we investigated the effects of habitat fragmentation and ecological parameters on the prevalence of blood-borne parasites (Plasmodium and Haemoproteus) in bird communities. Using mist-nets on forest edges and interiors, we sampled bird communities across six study sites: 3 large fragments (20–85 ha) and 3 continuous-forest sites. From 335 mist-net captures, we recorded 28 bird species and screened 299 bird samples with PCR to amplify and detect target DNA. Of the 28 bird species sampled, 19 were infected with Plasmodium and/or Haemoproteus and 9 species were without infection. Over one third of screened birds (99 individuals) were positive for Haemoproteus and/or Plasmodium. In forest fragments, bird capture rates were significantly higher than in continuous forests, but bird species richness did not differ. Unexpectedly, we found that the prevalence of the dominant haemosporidian infection, Haemoproteus, was significantly higher in continuous forest than in habitat fragments. Further, we found that ecological traits such as diet, foraging height, habitat specialisation and distributional ranges were significantly associated with blood-borne infections. PMID:24124541

Laurance, Susan G. W.; Jones, Dean; Westcott, David; Mckeown, Adam; Harrington, Graham; Hilbert, David W.

2013-01-01

243

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

USGS Publications Warehouse

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

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

2006-01-01

244

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

USGS Publications Warehouse

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

Wightman, C.; Fuller, Mark R.

2006-01-01

245

The relative effects of habitat loss, fragmentation, and degradation on population extinction  

EPA Science Inventory

The most prominent conservation concerns are typically habitat loss and habitat fragmentation. The role of habitat degradation has received comparatively little attention. But research has shown that the quality of habitat patches can significantly influence wildlife population d...

246

Does thermal variability experienced at the egg stage influence life history traits across life cycle stages in a small invertebrate?  

PubMed

Although effects of thermal stability on eggs have often been considered in vertebrates, there is little data thermal stability in insect eggs even though these eggs are often exposed in nature to widely fluctuating ambient conditions. The modularity of development in invertebrates might lead to compensation across life cycle stages but this remains to be tested particularly within the context of realistic temperature fluctuations encountered in nature. We simulated natural temperate fluctuations on eggs of the worldwide cruciferous insect pest, the diamondback moth (DBM), Plutella xylostella (L.), while maintaining the same mean temperature (25°C±0°C, 25±4°C, 25±6°C, 25±8°C, 25±10°C, 25±12°C) and assessed egg development, survival and life history traits across developmental stages. Moderate fluctuations (25±4°C, 25±6°C) did not influence performance compared to the constant temperature treatment, and none of the treatments influenced egg survival. However the wide fluctuating temperatures (25±10°C, 25±12°C) slowed development time and led to an increase in pre-pupal mass, although these changes did not translate into any effects on longevity or fecundity at the adult stage. These findings indicate that environmental effects can extend across developmental stages despite the modularity of moth development but also highlight that there are few fitness consequences of the most variable thermal conditions likely to be experienced by Plutella xylostella. PMID:24911213

Xing, Kun; Hoffmann, Ary A; Ma, Chun-Sen

2014-01-01

247

The influence of chronically and temporarily accessible information on life satisfaction judgments.  

PubMed

The authors examined the influence of temporarily and chronically accessible information on life satisfaction judgments. Meta-analyses revealed high retest-reliability of life satisfaction judgments and weak effects of the item order of domain and global satisfaction judgments. Study 1 (N=225) failed to replicate a widely cited finding of strong item-order effects. In Studies 2 (N=100), 3 (N=200), and 4 (N=222), chronically accessible information was a strong predictor of life satisfaction judgments, whereas item order had a relatively small effect. Study 5 (N=651) demonstrated that the results generalize to single item measures and judgments of shorter time periods. The results suggest that life satisfaction judgments are more heavily based on chronically accessible than temporarily accessible information. PMID:16248721

Schimmack, Ulrich; Oishi, Shigehiro

2005-09-01

248

Habitat Suitability Index Models: Red King Crab  

USGS Publications Warehouse

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for evaluating habitat of different life stages of red king crab (Paralithodes camtschatica). A model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat) in Alaskan coastal waters, especially in the Gulf of Alaska and the southeastern Bering Sea. HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

Jewett, Stephen C.; Onuf, Christopher P.

1988-01-01

249

Intercohort density dependence drives brown trout habitat selection  

NASA Astrophysics Data System (ADS)

Habitat selection can be viewed as an emergent property of the quality and availability of habitat but also of the number of individuals and the way they compete for its use. Consequently, habitat selection can change across years due to fluctuating resources or to changes in population numbers. However, habitat selection predictive models often do not account for ecological dynamics, especially density dependent processes. In stage-structured population, the strength of density dependent interactions between individuals of different age classes can exert a profound influence on population trajectories and evolutionary processes. In this study, we aimed to assess the effects of fluctuating densities of both older and younger competing life stages on the habitat selection patterns (described as univariate and multivariate resource selection functions) of young-of-the-year, juvenile and adult brown trout Salmo trutta. We observed all age classes were selective in habitat choice but changed their selection patterns across years consistently with variations in the densities of older but not of younger age classes. Trout of an age increased selectivity for positions highly selected by older individuals when their density decreased, but this pattern did not hold when the density of younger age classes varied. It suggests that younger individuals are dominated by older ones but can expand their range of selected habitats when density of competitors decreases, while older trout do not seem to consider the density of younger individuals when distributing themselves even though they can negatively affect their final performance. Since these results may entail critical implications for conservation and management practices based on habitat selection models, further research should involve a wider range of river typologies and/or longer time frames to fully understand the patterns of and the mechanisms underlying the operation of density dependence on brown trout habitat selection.

Ayllón, Daniel; Nicola, Graciela G.; Parra, Irene; Elvira, Benigno; Almodóvar, Ana

2013-01-01

250

Habitat selection in a rocky landscape: experimentally decoupling the influence of retreat site attributes from that of landscape features.  

PubMed

Organisms selecting retreat sites may evaluate not only the quality of the specific shelter, but also the proximity of that site to resources in the surrounding area. Distinguishing between habitat selection at these two spatial scales is complicated by co-variation among microhabitat factors (i.e., the attributes of individual retreat sites often correlate with their proximity to landscape features). Disentangling this co-variation may facilitate the restoration or conservation of threatened systems. To experimentally examine the role of landscape attributes in determining retreat-site quality for saxicolous ectotherms, we deployed 198 identical artificial rocks in open (sun-exposed) sites on sandstone outcrops in southeastern Australia, and recorded faunal usage of those retreat sites over the next 29 months. Several landscape-scale attributes were associated with occupancy of experimental rocks, but different features were important for different species. For example, endangered broad-headed snakes (Hoplocephalus bungaroides) preferred retreat sites close to cliff edges, flat rock spiders (Hemicloea major) preferred small outcrops, and velvet geckos (Oedura lesueurii) preferred rocks close to the cliff edge with higher-than-average sun exposure. Standardized retreat sites can provide robust experimental data on the effects of landscape-scale attributes on retreat site selection, revealing interspecific divergences among sympatric taxa that use similar habitats. PMID:22701592

Croak, Benjamin M; Pike, David A; Webb, Jonathan K; Shine, Richard

2012-01-01

251

Potential for anthropogenic disturbances to influence evolutionary change in the life history of a threatened salmonid  

PubMed Central

Although evolutionary change within most species is thought to occur slowly, recent studies have identified cases where evolutionary change has apparently occurred over a few generations. Anthropogenically altered environments appear particularly open to rapid evolutionary change over comparatively short time scales. Here, we consider a Pacific salmon population that may have experienced life-history evolution, in response to habitat alteration, within a few generations. Historically, juvenile fall Chinook salmon (Oncorhynchus tshawytscha) from the Snake River migrated as subyearlings to the ocean. With changed riverine conditions that resulted from hydropower dam construction, some juveniles now migrate as yearlings, but more interestingly, the yearling migration tactic has made a large contribution to adult returns over the last decade. Optimal life-history models suggest that yearling juvenile migrants currently have a higher fitness than subyearling migrants. Although phenotypic plasticity likely accounts for some of the change in migration tactics, we suggest that evolution also plays a significant role. Evolutionary change prompted by anthropogenic alterations to the environment has general implications for the recovery of endangered species. The case study we present herein illustrates the importance of integrating evolutionary considerations into conservation planning for species at risk.

Williams, John G; Zabel, Richard W; Waples, Robin S; Hutchings, Jeffrey A; Connor, William P

2008-01-01

252

Lifespan influences on mid- to late-life cognitive function in a Chinese birth cohort  

PubMed Central

Objective: To explore factors throughout the lifespan that influence cognition in midlife to late life. Methods: We conducted a retrospective birth cohort study of 2,062 individuals born during 1921-1954 in Beijing, China. In 2003-2005, birth records were abstracted, and participants then 50-82 years old received standardized examinations for health, cognition, and socio-environmental measures. Using cumulative logit models, we assessed adjusted relative effects of prenatal, early life, and adult factors on mid- to late-life cognition. Results: Most prenatal factors were associated with mid- to late-life cognition in the unadjusted models. However, when childhood and adult factors were sequentially added to the models, the impact of prenatal factors showed successive attenuation in effect size, and became insignificant. In contrast, early life factors remained significantly associated with mid- to late-life cognition even after full life-course adjustments. Specifically, those whose fathers had laborer vs professional occupations (odds ratio [OR]Laborer 1.74; 95% confidence interval [CI]: 1.25-2.42) had poorer cognitive outcomes, while individuals who drank milk daily in childhood (OR 0.65; 95% CI: 0.54-0.80), had more years of education (OR10-12 years 0.60; 95% CI: 0.45-0.81; OR13+ yrs 0.29; 95% CI: 0.23-0.38), and were taller adults (ORheight ? SD 0.65; 95% CI: 0.49-0.86) had better cognition. The high prenatal risk infants had similar patterns with a trend toward a stronger association between cognition and socioenvironmental factors. Conclusion: Mid- to late-life cognition is influenced by factors over the entire lifespan with the greatest impact coming from early life exposures. Nutrition, education, social, and family environment in early life may have a long-term impact on cognition in developing countries. GLOSSARY CI = confidence interval; HDL = high-density lipoprotein; LDL = low-density lipoprotein; OR = odds ratio; PUMCH = Peking Union Medical College Hospital; WAIS-R = Wechsler Adult Intelligence Scale-Revised; WISC-R = Wechsler Intelligence Scale for Children-Revised. PMID:19620606

Zhang, Z X.; Plassman, B L.; Xu, Q; Zahner, G E.P.; Wu, B; Gai, M Y.; Wen, H B.; Chen, X; Gao, S; Hu, D; Xiao, X H.; Shen, Y; Liu, A M.; Xu, T

2009-01-01

253

Habitat of In Vivo Transformation Influences the Levels of Free Radical Scavengers in Clinostomum complanatum: Implications for Free Radical Scavenger Based Vaccines against Trematode Infections  

PubMed Central

Background Since free radical scavengers of parasite origin like glutathione-S-transferase and superoxide dismutase are being explored as prospective vaccine targets, availability of these molecules within the parasite infecting different hosts as well as different sites of infection is of considerable importance. Using Clinostomum complanatum, as a model helminth parasite, we analysed the effects of habitat of in vivo transformation on free radical scavengers of this trematode parasite. Methods Using three different animal models for in vivo transformation and markedly different sites of infection, progenetic metacercaria of C. complanatum were transformed to adult ovigerous worms. Whole worm homogenates were used to estimate the levels of lipid peroxidation, a marker of oxidative stress and free radical scavengers. Results Site of in vivo transformation was found to drastically affect the levels of free radical scavengers in this model trematode parasite. It was observed that oxygen availability at the site of infection probably influences levels of free radical scavengers in trematode parasites. Conclusion This is the first report showing that habitat of in vivo transformation affects levels of free radical scavengers in trematode parasites. Since free radical scavengers are prospective vaccine targets and parasite infection at ectopic sites is common, we propose that infections at different sites, may respond differently to free radical scavenger based vaccines. PMID:24759940

Ahmad, Irshad; Ahmad, Masood

2014-01-01

254

Ambrosia beetle habitat use, host use, and influence on early wood colonizing microbes in an oak-hickory forest .  

E-print Network

??Knowledge of how exotic ambrosia beetles influence microbe communities and how forest characteristics affect ambrosia beetle abundance will improve policy and management decision. This study… (more)

Reed, Sharon E., 1977-

2010-01-01

255

Influence of beaver impoundments on vegetative composition, and modeling habitat suitability as a tool for wildlife management and conservation.  

E-print Network

??Beavers (Castor canadensis) can have dramatic effects on vegetative communities through impounding streams and wetlands. These alterations may influence rare plant species where beaver create… (more)

Bonner, Jerri LeAnne.

2005-01-01

256

Hyperlink Habitats  

NSDL National Science Digital Library

This activity is designed to help students understand the complexity of nature by utilizing an online illustration of the ways in which various elements of a rainforest ecosystem are interconnected. Students will map the online habitat and create their own hyperlink habitat, either in print or on the Web, for a local ecosystem. When they are finished, they can submit their work to the Discovery Channel School.

257

Utilising statistical residual life estimates of bearings to quantify the influence of preventive maintenance actions  

NASA Astrophysics Data System (ADS)

In this paper it is illustrated how statistical residual life estimates of bearings can be used to justify maintenance practices. Residual life estimates are based on Proportional Intensity Models for non-repairable systems utilising historic failure data and corresponding diagnostic measurements. A case study is presented where failure and diagnostic data obtained from roller bearings operating in the dryer section of a paper machine are used to predict future failure times of bearings. If these predictions are compared to the diagnostic measurements, i.e. vibration and lubrication levels, it becomes evident how changes in these diagnostic measurements influence the residual life of the bearings. From this it is possible to justify maintenance practices.

Vlok, Pieter-Jan; Wnek, Maciej; Zygmunt, Maciej

2004-07-01

258

Life Experiences and Resilience in College Students: A Relationship Influenced by Hope and Mindfulness  

E-print Network

LIFE EXPERIENCES AND RESILIENCE IN COLLEGE STUDENTS: A RELATIONSHIP INFLUENCED BY HOPE AND MINDFULNESS A Dissertation by AMY BETH COLLINS Submitted to the Office of Graduate Studies of Texas A&M University in partial... Dissertation by AMY BETH COLLINS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Michael Duffy Committee...

Collins, Amy B.

2010-01-16

259

Current Life Concerns of Early Adolescents and Their Mothers:Influence of Maternal Hiv  

Microsoft Academic Search

Focus group discussions were conducted with inner-city ethnic minority families with regard to current life concerns, motherchild communication of concerns, and the influence of maternal HIV on both of those issues. Participants included early adolescents who were HIV-negative and their mothers (one-half were HIV-positive and one-half HIV-negative). Early adolescents were most concerned about sexual activity, pregnancy, safety and violence, and

Elizabeth Brackis-Cott; Claude Ann Mellins; Megan Block

2003-01-01

260

Body mass index in mid-life women: relative influence of menopause, hormone use, and ethnicity  

Microsoft Academic Search

OBJECTIVE: To assess the relative influence of menopausal status and hormone use on body mass index (BMI) among a multiethnic sample of mid-life women.DESIGN: Cross-sectional telephone survey conducted at seven sites where each site targeted an ethnic minority group and Caucasians as part of Study of Women's Health Across the Nation (SWAN).SUBJECTS: A total of 7181 Caucasians, 3949 African-Americans, 1660

Karen A. Matthews; B Abrams; Sybil L. Crawford; T Miles; R Neer; LH Powell; D Wesley

2001-01-01

261

Healthcare professionals' views on factors influencing end-of-life care in hospitals  

Microsoft Academic Search

AbstractIntroduction and aimsThe majority of patients die in the acute setting, yet care delivered to the dying in hospitals is variable and the underlying reasons for this are not documented well. We aimed to explore healthcare professionals' views on the factors influencing good quality end-of-life care within an acute hospital Trust.MethodsWithin a feasibility study examining the impact of a simple

K Forbes; J Gibbins; M E Burcombe; S J Bloor; C M Reid; R C McCoubrie

2011-01-01

262

Influence of shot peening on the fatigue life of laser hardened 17-4PH steel  

Microsoft Academic Search

In order to improve the fatigue life of 17-4PH steel after laser hardening treatment, shot peening and dual shot peening treatments were performed on laser hardened 17-4PH steel in this paper. Characteristic changes of the roughness, hardness and residual stress distribution in three typical areas were discussed in order to gain a better understanding about the shot peening influence on

Zhou Wang; Chuanhai Jiang; Xiaoyan Gan; Yanhua Chen; Vincent Ji

2011-01-01

263

Influence of local habitat features on disease avoidance by Caribbean spiny lobsters in a casita-enhanced bay.  

PubMed

In Bahía de la Ascensión, Mexico, 'casitas' (large artificial shelters) are extensively used to harvest Caribbean spiny lobsters Panulirus argus. After the discovery of a pathogenic virus, Panulirus argus virus 1 (PaV1), in these lobsters, laboratory experiments revealed that PaV1 could be transmitted by contact and through water, and that lobsters avoided shelters harboring diseased conspecifics. To examine these issues in the context of casitas, which typically harbor multiple lobsters of all sizes, we examined the distribution and aggregation patterns of lobsters in the absence/presence of diseased conspecifics (i.e. visibly infected with PaV1) in 531 casitas distributed over 3 bay zones, 1 poorly vegetated ('Vigía Chico', average depth: 1.5 m) and 2 more extensively vegetated ('Punta Allen': 2.5 m; 'Los Cayos': 2.4 m). All zones had relatively high indices of predation risk. Using several statistical approaches, we found that distribution parameters of lobsters were generally not affected by the presence of diseased conspecifics in casitas. Interestingly, however, in the shallower and less vegetated zone (Vigía Chico), individual casitas harbored more lobsters and lobsters were actually more crowded in casitas containing diseased conspecifics, yet disease prevalence was the lowest in lobsters of all sizes. These results suggest that (1) investment in disease avoidance by lobsters is partially modulated by local habitat features, (2) contact transmission rates of PaV1 may be lower in nature than in the laboratory, and (3) water-borne transmission rates may be lower in shallow, poorly vegetated habitats more exposed to solar ultraviolet radiation, which can damage viral particles. PMID:23186701

Briones-Fourzán, Patricia; Candia-Zulbarán, Rebeca I; Negrete-Soto, Fernando; Barradas-Ortiz, Cecilia; Huchin-Mian, Juan P; Lozano-Álvarez, Enrique

2012-08-27

264

Habitat Type Influences the Microhabitat Preference of Juvenile Tiger Prawns ( Penaeus esculentusHaswell and Penaeus semisulcatusDe Haan)  

NASA Astrophysics Data System (ADS)

The microhabitat preferences of juvenile tiger prawns (3-10 mm carapace length), Penaeus esculentusand Penaeus semisulcatus, were tested in the field at Groote Eylandt, in the western Gulf of Carpentaria, Australia. A partitioned apparatus containing live seagrass was used. Both species of prawns selected seagrass ( Syringodium isoetifolium) over bare substrate. Juvenile P. esculentus, the most abundant species in this region, were also given paired choices of seagrasses with different leaf morphologies (representing a range of structural complexity) and sediments of different particle size. They selected a seagrass with broad, long leaves ( Cymodocea serrulata) over one with narrow, long leaves ( S. isoetifolium), which in turn was selected over the seagrasses with narrow, short leaves ( Halodule uninervisand shortened S. isoetifolium). Predation experiments have shown that juvenile P. esculentusare detected and eaten less often in broad, long-leaved seagrass than in narrow, short-leaved seagrass or bare substrate, so their preference for the former may shelter them from predators. No habitat preference was evident for P. esculentuswhen offered a choice between sediments consisting mainly of sand (71% sand particles) and silt (60% of silt and clay). The selection by both species of tiger prawn of seagrass over bare substrate, and P. esculentus's selection of seagrass with long, broad leaves, provides an explanation for the distribution of juvenile tiger prawns in the field. Thus, in the seagrass beds around Groote Eylandt, P. esculentusis more abundant in seagrass with broad, long leaves than in seagrass with short, thin leaves. In addition, its distribution in this region is relatively independent of sediment type. Leaf surface area (or habitat structural complexity) appears to be the main determinant of distribution for juvenile P. esculentus.

Kenyon, R. A.; Loneragan, N. R.; Hughes, J. M.; Staples, D. J.

1997-09-01

265

Influence of habitat, litter type, and soil invertebrates on leaf-litter decomposition in a fragmented Amazonian landscape.  

PubMed

Amazonian forest fragments and second-growth forests often differ substantially from undisturbed forests in their microclimate, plant-species composition, and soil fauna. To determine if these changes could affect litter decomposition, we quantified the mass loss of two contrasting leaf-litter mixtures, in the presence or absence of soil macroinvertebrates, and in three forest habitats. Leaf-litter decomposition rates in second-growth forests (>10 years old) and in fragment edges (<100 m from the edge) did not differ from that in the forest interior (>250 m from the edges of primary forests). In all three habitats, experimental exclusion of soil invertebrates resulted in slower decomposition rates. Faunal-exclosure effects were stronger for litter of the primary forest, composed mostly of leaves of old-growth trees, than for litter of second-growth forests, which was dominated by leaves of successional species. The latter had a significantly lower initial concentration of N, higher C:N and lignin:N ratios, and decomposed at a slower rate than did litter from forest interiors. Our results indicate that land-cover changes in Amazonia affect decomposition mainly through changes in plant species composition, which in turn affect litter quality. Similar effects may occur on fragment edges, particularly on very disturbed edges, where successional trees become dominant. The drier microclimatic conditions in fragment edges and second-growth forests (>10 years old) did not appear to inhibit decomposition. Finally, although soil invertebrates play a key role in leaf-litter decomposition, we found no evidence that differences in the abundance, species richness, or species composition of invertebrates between disturbed and undisturbed forests significantly altered decomposition rates. PMID:15942762

Vasconcelos, Heraldo L; Laurance, William F

2005-07-01

266

10/24/13 nsf.gov -National Science Foundation (NSF) News -Habitat research methods give a new peek at tiger life with conservation -US National Science Foundat... nsf.gov/news/news_summ.jsp?cntn_id=129355 1/1  

E-print Network

10/24/13 nsf.gov - National Science Foundation (NSF) News - Habitat research methods give a new.gov/news/news_summ.jsp?cntn_id=129355 1/1 News From the Field HABITAT RESEARCH METHODS GIVE A NEW PEEK AT TIGER LIFE

267

[The influence of meaning making following stressful life experiences on change of self-concept].  

PubMed

As interest in meaning making following stressful life experiences continues to grow, it is important to clarify the features and functions of the meaning- making process. We examined the influence of meaning making following stressful life experiences on change of self-concept. In two studies, university students selected their most stressful life experience and completed the Assimilation and Accommodation of Meaning Making Scale. In Study 1, 235 university students also completed questionnaires regarding post-traumatic growth and positive change of the sense of identity following their stressful life experience. The results of covariance structure analysis indicated that accommodation promoted a positive change of self-concept. In Study 2, 199 university students completed questionnaires regarding change of self-concept and emotion as a positive or negative change following stressful life experiences. The results of covariance structure analysis indicated that accommodation promoted a positive change, similar to the results of Study 1. In addition, accommodation also promoted negative change. However, assimilation did not promote positive change but did restrain negative change. PMID:24205743

Horita, Ryo; Sugie, Masashi

2013-10-01

268

Stressors and antistressors: how do they influence life span in HER-2/neu transgenic mice?  

PubMed

The purpose of this study is to investigate possible influences of different stressors (saline injections, light deprivation and constant light regimen) and geroprotectors (Epitalon and melatonin) on survivals of female HER-2/neu transgenic mice. We propose a semi-parametric model of heterogeneous mortality (frailty model) for the analysis of the experimental data. In this model, we assume that treatment influences parameters of both frailty distribution and baseline hazard. The unique design of the experiments makes it possible to compare the effects on survival produced by different treatments in terms of changes in population heterogeneity and underlying hazard. Parameters of the model help to describe the possible influences of various stressors, geroprotectors, and their dosage on the life span of laboratory animals. The proposed model helps to advance our understanding of the effects--such as debilitation, longevity hormesis and incomplete hormesis--which occur in the population as a result of different treatments. PMID:15501020

Semenchenko, Ganna V; Anisimov, Vladimir N; Yashin, Anatoli I

2004-10-01

269

The Influence of Free Space Environment in the Mission Life Cycle: Material Selection  

NASA Technical Reports Server (NTRS)

The natural space environment has a great influence on the ability of space systems to perform according to mission design specification. Understanding the natural space environment and its influence on space system performance is critical to the concept formulation, design, development, and operation of space systems. Compatibility with the natural space environment is a primary factor in determining the functional lifetime of the space system. Space systems being designed and developed today are growing in complexity. In many instances, the increased complexity also increases its sensitivity to space environmental effects. Sensitivities to the natural space environment can be tempered through appropriate design measures, material selection, ground processing, mitigation strategies, and/or the acceptance of known risks. The design engineer must understand the effects of the natural space environment on the space system and its components. This paper will discuss the influence of the natural space environment in the mission life cycle with a specific focus on the role of material selection.

Edwards, David L.; Burns, Howard D.; de Groh, Kim K.

2014-01-01

270

INFLUENCES OF GENDER IDEOLOGY AND HOUSEWORK ALLOCATION ON WOMEN'S EMPLOYMENT OVER THE LIFE COURSE  

PubMed Central

The study investigates the influences of women’s attitudes about gender and couples’ housework allocation patterns on women’s employment status and work hours across the life course. The influence of these factors on the employment characteristics of continuously married women is investigated at four time points: 1977, 1980, 1985, and 1993. Data come from the Intergenerational Panel Study of Parents and Children and the analysis sample includes 556 continuously married women. Findings from structural equation, fixed effects, and tobit models offer consistent evidence of long-term positive influences of women’s egalitarian gender ideology and men’s participation in routine housework on women’s labor force participation. The results provide support for hypotheses based on the notion of lagged adaptation. PMID:19255608

Cunningham, Mick

2008-01-01

271

Mycorrhizal Associations, Life History, and Habitat Characteristics of the Endangered Terrestrial Orchid Spiranthes parksii Correll and Sympatric Congener Spiranthes cernua: Implications for Conservation  

E-print Network

Spiranthes parksii Correll is a federally listed endangered terrestrial orchid endemic of Texas. The species exhibit a very limited geographic distribution and most remaining populations are threatened by habitat loss and fragmentation. Development...

Ariza, Martha C

2013-12-10

272

Structurally complex habitats provided by Acropora palmata influence ecosystem processes on a reef in the Florida Keys National Marine Sanctuary  

NASA Astrophysics Data System (ADS)

The disappearance of Acropora palmata from reefs in the Florida Keys National Marine Sanctuary (FKNMS) represents a significant loss in the amount of structurally complex habitat available for reef-associated species. The consequences of such a widespread loss of complex structure on ecosystem processes are still unclear. We sought to determine whether the disappearance of complex structure has adversely affected grazing and invertebrate predation rates on a shallow reef in the FKNMS. Surprisingly, we found grazing rates and invertebrate predation rates were lower in the structurally complex A. palmata branches than on the topographically simple degraded reefs. We attribute these results to high densities of aggressively territorial damselfish, Stegastes planifrons, living within A. palmata. Our study suggests the presence of agonistic damselfish can cause the realized spatial patterns of ecosystem processes to deviate from the expected patterns. Reef ecologists must therefore carefully consider the assemblage of associate fish communities when assessing how the mortality of A. palmata has affected coral reef ecosystem processes.

Lemoine, N. P.; Valentine, J. F.

2012-09-01

273

Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions  

PubMed Central

Background Viability in a non dividing state is referred to as chronological life span (CLS). Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercetin and resveratrol have negative impacts on CLS under winemaking conditions, an unexpected behavior for these potential anti-oxidants. We observed that quercetin inhibits alcohol and aldehyde dehydrogenase activities, and that resveratrol performs a pro-oxidant role during grape juice fermentation. Vitamins nicotinic acid and nicotinamide are precursors of NAD+, and their addition reduces mean longevity during fermentation, suggesting a metabolic unbalance negative for CLS. Moreover, vitamin mix supplementation at the end of fermentation shortens CLS and enhances cell lysis, while amino acids increase life span. Conclusions Wine S. cerevisiae strains are able to sense changes in the environmental conditions and adapt their longevity to them. Yeast death is influenced by the conditions present at the end of wine fermentation, particularly by the concentration of two-carbon metabolites produced by the fermentative metabolism, such as ethanol, acetic acid and acetaldehyde, and also by the grape juice composition, particularly its vitamin content. PMID:22873488

2012-01-01

274

Influence of functional movement rehabilitation on quality of life in people with Parkinson's disease.  

PubMed

[Purpose] Parkinson's disease is one of the most frequent diseases of the central nervous system. Thorough knowledge of reasons for movement defects may contribute to the ability to quality of life at a good level as far as motor abilities are concerned. The aim of the study was to evaluate the influence of functional movement rehabilitation on the degree of intensity of movement symptoms in Parkinson's disease. [Subjects] The research was carried out in people diagnosed with stage III Parkinson's disease, according to the Hoehn and Yahr scale classification. [Methods] In order to establish the clinical state of patients, parts I, II, and III of the Unified Parkinson's Disease Rating Scale, the Schwab and England Activities of Daily Living scale, and the quality of life in Parkinson's disease questionnaire were applied. The intervention group took part in 60 minutes of functional movement rehabilitation twice a week for a period of 15 weeks. The main emphasis was placed on the ability to cope with everyday activities. [Results] A significant difference in scores for the given scales between before and after research the intervention period was observed in the intervention group. [Conclusion] The obtained results revealed positive that the influence of applied rehabilitation program had a positive influence on the degree of intensity of movement symptoms in people with Parkinson's disease. PMID:25276010

Cholewa, Joanna; Gorzkowska, Agnieszka; Szepelawy, Michal; Nawrocka, Agnieszka; Cholewa, Jaroslaw

2014-09-01

275

Environmental contingency in life history strategies: the influence of mortality and socioeconomic status on reproductive timing.  

PubMed

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one's resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner--to want children now, even at the cost of furthering one's education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction--to further one's education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size. PMID:20873933

Griskevicius, Vladas; Delton, Andrew W; Robertson, Theresa E; Tybur, Joshua M

2011-02-01

276

Influence of Functional Movement Rehabilitation on Quality of Life in People with Parkinson's Disease  

PubMed Central

[Purpose] Parkinson’s disease is one of the most frequent diseases of the central nervous system. Thorough knowledge of reasons for movement defects may contribute to the ability to quality of life at a good level as far as motor abilities are concerned. The aim of the study was to evaluate the influence of functional movement rehabilitation on the degree of intensity of movement symptoms in Parkinson’s disease. [Subjects] The research was carried out in people diagnosed with stage III Parkinson’s disease, according to the Hoehn and Yahr scale classification. [Methods] In order to establish the clinical state of patients, parts I, II, and III of the Unified Parkinson’s Disease Rating Scale, the Schwab and England Activities of Daily Living scale, and the quality of life in Parkinson’s disease questionnaire were applied. The intervention group took part in 60 minutes of functional movement rehabilitation twice a week for a period of 15 weeks. The main emphasis was placed on the ability to cope with everyday activities. [Results] A significant difference in scores for the given scales between before and after research the intervention period was observed in the intervention group. [Conclusion] The obtained results revealed positive that the influence of applied rehabilitation program had a positive influence on the degree of intensity of movement symptoms in people with Parkinson’s disease. PMID:25276010

Cholewa, Joanna; Gorzkowska, Agnieszka; Szepelawy, Michal; Nawrocka, Agnieszka; Cholewa, Jaroslaw

2014-01-01

277

Environmental Contingency in Life History Strategies: The Influence of Mortality and Socioeconomic Status on Reproductive Timing  

PubMed Central

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one’s resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner—to want children now, even at the cost of furthering one’s education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction—to further one’s education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size. PMID:20873933

Griskevicius, Vladas; Delton, Andrew W.; Robertson, Theresa E.; Tybur, Joshua M.

2013-01-01

278

Influence of Sleep Disturbances on Quality of Life of Iranian Menopausal Women  

PubMed Central

Background. Subjective sleep disturbances increase during menopause. Some problems commonly encountered during menopause, such as hot flushes and sweating at night, can cause women to have difficulty in sleeping. These complaints can influence quality of life of menopausal women. Methods. This cross-sectional study was performed on menopausal women attending health centers in Qazvin for periodic assessments. We measured excessive daytime sleepiness by Epworth sleepiness scale (ESS), obstructive sleep apnea (OSA) by the Berlin questionnaire, and insomnia by the insomnia severity index (ISI). We evaluate quality of life by the Menopause specific quality of life questionnaire (MENQOL). Results. A total of 380 menopausal women entered the study. Mean age of participated women was 57.6 ± 6.02. Mean duration of menopause was 6.3 ± 4.6. The frequency of severe and moderate insomnia was 8.4% (32) and 11.8% (45). Severe daytime sleepiness (ESS???10) was present in 27.9% (80) of the participants. Multivariate analytic results show that insomnia and daytime sleepiness have independent negative impact on each domain and total score of MENQOL questionnaire. Conclusion. According to our findings, EDS and insomnia are frequent in menopausal women. Both EDS and insomnia have significant quality of life impairment. PMID:24286070

Yazdi, Zohreh; Sadeghniiat-Haghighi, Khosro; Ziaee, Amir; Elmizadeh, Khadijeh; Ziaeeha, Masomeh

2013-01-01

279

Influence of oceanic factors on Anguilla anguilla (L.) over the twentieth century in coastal habitats of the Skagerrak, southern Norway  

PubMed Central

The European eel (Anguilla anguilla L.) is distributed in coastal and inland habitats all over Europe, but spawns in the Sargasso Sea and is thus affected by both continental and oceanic factors. Since the 1980s a steady decline has been observed in the recruitment of glass eels to freshwater and in total eel landings. The eel is considered as critically endangered on the International Union for the Conservation of Nature and Natural Resources Red List of species. The Skagerrak beach seine survey from Norway constitutes the longest fishery-independent dataset on yellow/silver eels (starting in 1904). The Skagerrak coastal region receives larvae born in the Sargasso Sea spawning areas that have followed the Gulf Stream/North Atlantic Drift before they penetrate far into the North Sea. The Skagerrak coastal time series is therefore particularly valuable for exploring the impacts of oceanic factors on fluctuations in eel recruitment abundance. Analyses showed that Sargasso Sea surface temperature was negatively correlated with eel abundance, with a lag of 12 years revealing a cyclic and detrimental effect of high temperatures on the newly hatched larvae. The North Atlantic Oscillation index and inflow of North Atlantic water into the North Sea were negatively correlated with eel abundance, with a lag of 11 years. Increased currents towards the North Atlantic during high North Atlantic Oscillation years may send larvae into the subpolar gyre before they are ready to metamorphose and settle, resulting in low recruitment in the northern part of the distribution area for these years. The Skagerrak time series was compared with glass eel recruitment to freshwater in the Netherlands (Den Oever glass eel time series), and similar patterns were found revealing a cycle linked to changes in oceanic factors affecting glass eel recruitment. The recent decline of eels in the Skagerrak also coincided with previously documented shifts in environmental conditions of the North Sea ecosystem. PMID:20798112

Durif, Caroline M. F.; Gj?saeter, Jakob; V?llestad, L. Asbj?rn

2011-01-01

280

Influence of oceanic factors on Anguilla anguilla (L.) over the twentieth century in coastal habitats of the Skagerrak, southern Norway.  

PubMed

The European eel (Anguilla anguilla L.) is distributed in coastal and inland habitats all over Europe, but spawns in the Sargasso Sea and is thus affected by both continental and oceanic factors. Since the 1980s a steady decline has been observed in the recruitment of glass eels to freshwater and in total eel landings. The eel is considered as critically endangered on the International Union for the Conservation of Nature and Natural Resources Red List of species. The Skagerrak beach seine survey from Norway constitutes the longest fishery-independent dataset on yellow/silver eels (starting in 1904). The Skagerrak coastal region receives larvae born in the Sargasso Sea spawning areas that have followed the Gulf Stream/North Atlantic Drift before they penetrate far into the North Sea. The Skagerrak coastal time series is therefore particularly valuable for exploring the impacts of oceanic factors on fluctuations in eel recruitment abundance. Analyses showed that Sargasso Sea surface temperature was negatively correlated with eel abundance, with a lag of 12 years revealing a cyclic and detrimental effect of high temperatures on the newly hatched larvae. The North Atlantic Oscillation index and inflow of North Atlantic water into the North Sea were negatively correlated with eel abundance, with a lag of 11 years. Increased currents towards the North Atlantic during high North Atlantic Oscillation years may send larvae into the subpolar gyre before they are ready to metamorphose and settle, resulting in low recruitment in the northern part of the distribution area for these years. The Skagerrak time series was compared with glass eel recruitment to freshwater in the Netherlands (Den Oever glass eel time series), and similar patterns were found revealing a cycle linked to changes in oceanic factors affecting glass eel recruitment. The recent decline of eels in the Skagerrak also coincided with previously documented shifts in environmental conditions of the North Sea ecosystem. PMID:20798112

Durif, Caroline M F; Gjøsaeter, Jakob; Vøllestad, L Asbjørn

2011-02-01

281

Does decoration building influence antipredator responses in an orb-web spider ( Argiope keyserlingi ) in its natural habitat?  

Microsoft Academic Search

Antipredator strategies adopted by animals need to compensate for temporal changes. Many orb-web spiders add silk decorations to their webs, which principally attract prey but may attract some predators. To identify their influence on antipredator behaviour in adult female St Andrew's cross spiders (Argiope keyserlingi) we measured: spider body condition, web characteristics (area, spiral length and decoration building), environmental variables

Sean J. Blamires; Dieter F. Hochuli; Michael B. Thompson

2007-01-01

282

Evaluating the influence of macrophytes on algal and bacterial production in multiple habitats of a freshwater wetland  

Microsoft Academic Search

Algal 14 C uptake and bacterial 3 H leucine incorporation were measured over 20 months to assess the influence of macrophytes on the spatial distribution and magnitude of microbial production and the relative importance of algae versus macrophytes to whole-system energy flow in a southeastern U.S. wetland. Algal and bacterial produc- tion were determined for water column and plant-, sediment-,

Emily H. Stanley; Mark D. Johnson; Amelia K. Ward

2003-01-01

283

Family and Community Influences on Health and Socioeconomic Status: Sibling Correlations Over the Life Course.  

PubMed

This paper presents new estimates of sibling correlations in health and socioeconomic outcomes over the life course in the U.S. Sibling correlations provide an omnibus measure of the importance of all family and community influences. I find that sibling correlations in a range of health and socioeconomic outcomes start quite high at birth and remain high over the life course. The sibling correlation in birth weight is estimated to be 0.5. Sibling correlations in test scores during childhood are as high as 0.6. Sibling correlations in adult men's wages are also around 0.5. Decompositions provide suggestive evidence on which pathways may account for the gradients in health and SES by family background. For example, sibling correlations in cognitive skills and non-cognitive skills during childhood are lower controlling for family income. Similarly, parent education levels can account for a sizable portion of the correlation in adult health status among brothers. PMID:23412989

Mazumder, Bhashkar

2011-09-01

284

Ecology of Neoschongastia americana (Hirst): laboratory life cycle, developmental period in the field and influence of selected external factors.  

E-print Network

ECOLOGY OF NEOSCHONGASTIA AMERICANA (HIRST): LABORATORY LIFE CYCLE, DEVELOPMENTAL PERIOD IN THE FIELD AND INFLUENCE OF SELECTED EXTERNAL FACTORS A Thesis by JERRY REAL CUNNINGHAM Submitted to the Graduate College of Texas A&? University... in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 19/4 Major Subject: Entomology ECOLOGY OF NEOSCHONGASTIA AMERICANA (HIRST): LABORATORY LIFE CYCLE, DEVELOPMENTAL PERIOD IN THE FIELD AND INFLUENCE OF SELECTED EXTERNAL...

Cunningham, Jerry Real

2012-06-07

285

Influence of selfing and maternal effects on life-cycle traits and dispersal ability in the herb Hypochaeris radicata (Asteraceae)  

Microsoft Academic Search

The ecological and evolutionary implications of dispersal are many. Pollination type and maternal effects may affect plant fitness traits, including life-cycle traits as well as dispersal ability. This study investigated the joint influence of pollination type and maternal effects on both life-cycle traits and dispersal ability in the herb Hypochaeris radicata. We conducted experimental crosses to obtain selfed and outcrossed

F. X. Pico Mercader; N. JOOP OUBORG; JAN VAN GROENENDAEL

2004-01-01

286

The Teacher I Wish to Be: Exploring the Influence of Life Histories on Student Teacher Idealised Identities  

ERIC Educational Resources Information Center

This paper examines the influence of life histories and apprenticeship of observation on the formation of student teachers' idealised identities. The life histories of 15 student teachers are decoded. Through eliciting from the student teachers the teacher they wish to be, the paper focuses on the interplay between the personal histories and ideal…

Furlong, Catherine

2013-01-01

287

Influence of dams and habitat condition on the distribution of redhorse ( Moxostoma ) species in the Grand River watershed, Ontario  

Microsoft Academic Search

Redhorse, Moxostoma spp., are considered to be negatively affected by dams although this assertion is untested for Canadian populations. One\\u000a hundred and fifty-one sites in the Grand River watershed were sampled to identify factors influencing the distribution of\\u000a redhorse species. Individual species of redhorse were captured from 3 to 32% of sites. The most widespread species were golden\\u000a redhorse, M.

Scott M. Reid; Nicholas E. Mandrak; Leon M. Carl; Chris C. Wilson

2008-01-01

288

Factors influencing the quality of life of Moroccan patients with juvenile idiopathic arthritis.  

PubMed

The aim of our study is to investigate the factors influencing the quality of life, assessed by the Pediatric Quality of Life Inventory 4.0 (PedsQL4) Generic Score Scales, in Moroccan patients with juvenile idiopathic arthritis. This is a cross-sectional study conducted between January and June 2012, covering children with juvenile idiopathic arthritis (JIA) seen at the consultations of El Ayachi Hospital and Children's Hospital of the University Hospital of Rabat. Quality of life is assessed by the PedsQL4 which is a questionnaire composed of 23 items, completed by the child and the parent; the response to each item ranges from 0 to 100, so that higher scores indicate a better quality of life. The functional impact is assessed by the Childhood Health Assessment Questionnaire (CHAQ), and the disease activity by the number of tender and swollen joints, visual analogue scale (VAS) activity, erythrocyte sedimentation rate (ESR), and C-reactive protein. Forty-seven patients are included; the average age of the patients is 11?±?3.35 years, and 40.4 % are females, with a median disease duration of 4 (2; 6) years. The oligoarticular form presents 26.7 %, the systemic form 24.4 %, and the enthesic form 22.2 %. The median of PedsQL4 is 80.43 (63.19; 92.93), and the median of the CHAQ is 0 (0; 1). Our study shows that some clinical and biological characteristics have significant effects on PedsQL by both parent and child reports. This study suggests that the achievement of the quality of life of our patients with JIA depends on the disease activity measured by swollen joints, the number of awakenings, parent VAS, physician VAS, patient VAS, and the ESR. PMID:24445385

Ezzahri, M; Amine, B; Rostom, S; Badri, D; Mawani, N; Gueddari, S; Shyen, S; Wabi, M; Moussa, F; Abouqal, R; Chkirate, B; Hajjaj-Hassouni, N

2014-11-01

289

Walking in simulated Martian gravity: influence of the portable life support system's design on dynamic stability.  

PubMed

With human exploration of the moon and Mars on the horizon, research considerations for space suit redesign have surfaced. The portable life support system (PLSS) used in conjunction with the space suit during the Apollo missions may have influenced the dynamic balance of the gait pattern. This investigation explored potential issues with the PLSS design that may arise during the Mars exploration. A better understanding of how the location of the PLSS load influences the dynamic stability of the gait pattern may provide insight, such that space missions may have more productive missions with a smaller risk of injury and damaging equipment while falling. We explored the influence the PLSS load position had on the dynamic stability of the walking pattern. While walking, participants wore a device built to simulate possible PLSS load configurations. Floquet and Lyapunov analysis techniques were used to quantify the dynamic stability of the gait pattern. The dynamic stability of the gait pattern was influenced by the position of load. PLSS loads that are placed high and forward on the torso resulted in less dynamically stable walking patterns than loads placed evenly and low on the torso. Furthermore, the kinematic results demonstrated that all joints of the lower extremity may be important for adjusting to different load placements and maintaining dynamic stability. Space scientists and engineers may want to consider PLSS designs that distribute loads evenly and low, and space suit designs that will not limit the sagittal plane range of motion at the lower extremity joints. PMID:19725694

Scott-Pandorf, Melissa M; O'Connor, Daniel P; Layne, Charles S; Josi?, Kresimir; Kurz, Max J

2009-09-01

290

Ghosts of habitats past: Contribution of landscape change to current habitats used by shrubland birds  

USGS Publications Warehouse

Models of habitat associations for species often are developed with an implicit 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 landscapes undergoing predominantly large-scale, radical, and unidirectional habitat change because wildfires are converting shrublands into expanses of exotic annual grasslands. We used data from field surveys and satellite image analyses in a series of redundancy analyses to partition variances and to determine the relative contribution of habitat change and current landscapes. Although current habitats explained a greater proportion of total variation, changes in habitat and measures of habitat richness and texture also contributed to variation in abundance of Horned Larks (Eremophila alpestris), Brewera??s Sparrows (Spizella breweri), and Sage Sparrows (Amphispiza belli). Abundance of birds was insensitive to scale for nonspatial habitat variables. In contrast, spatial measures of habitat richness and texture in the landscape were significant only at large spatial scales. Abundance of Horned Larks, Western Meadowlarks (Sturnella neglecta), and Brewera??s Sparrows, but not Sage Thrashers (Oreoscoptes montanus) or Sage Sparrows, was positively correlated with changes toward stable habitats. Because dominant habitat changes were toward less stable conditions, regional declines of those birds in shrubsteppe habitats reflect current landscapes as well as the history, magnitude, and trajectory of habitat change.

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

2000-01-01

291

Estimating the influence of life satisfaction and positive affect on later income using sibling fixed effects.  

PubMed

The question of whether there is a connection between income and psychological well-being is a long-studied issue across the social, psychological, and behavioral sciences. Much research has found that richer people tend to be happier. However, relatively little attention has been paid to whether happier individuals perform better financially in the first place. This possibility of reverse causality is arguably understudied. Using data from a large US representative panel, we show that adolescents and young adults who report higher life satisfaction or positive affect grow up to earn significantly higher levels of income later in life. We focus on earnings approximately one decade after the person's well-being is measured; we exploit the availability of sibling clusters to introduce family fixed effects; we account for the human capacity to imagine later socioeconomic outcomes and to anticipate the resulting feelings in current well-being. The study's results are robust to the inclusion of controls such as education, intelligence quotient, physical health, height, self-esteem, and later happiness. We consider how psychological well-being may influence income. Sobel-Goodman mediation tests reveal direct and indirect effects that carry the influence from happiness to income. Significant mediating pathways include a higher probability of obtaining a college degree, getting hired and promoted, having higher degrees of optimism and extraversion, and less neuroticism. PMID:23169627

De Neve, Jan-Emmanuel; Oswald, Andrew J

2012-12-01

292

Multi-scale geomorphic and hydrogeologic influences on bull trout (Salvelinus confluentus) spawning habitat in headwater streams  

NASA Astrophysics Data System (ADS)

We investigated multi-scale hydrogeomorphic influences on the distribution and abundance of bull trout (Salvelinus confluentus) spawning in snowmelt- dominated streams of the upper Flathead River basin, northwestern Montana. Bull trout redds were primarily found in unconfined alluvial valley reaches (74%), which were strongly influenced by hyporheic and groundwater-stream water exchange. A considerable proportion of redds (26%), however, were patchily distributed in confined valley reaches. Among all reaches and subreaches, the abundance of redds increased with increased bankfull dimensionless shear stress and decreased with reach-average streambed grain size (p < 0.05). Within these selected reaches and subreaches, redd occurrence tended to be associated with the finest available textural facies (i.e., gravel and small cobble substrates) in concave-up bedforms with downwelling intragravel flows. Streambed temperatures tracked stream water diurnal temperature cycles to a depth of at least 25 cm. Groundwater provided substantial thermal moderation of stream water for several high-density spawning reaches. Our spawning gravel competence results indicate that bull trout select spawning areas that are potentially susceptible to flooding-induced scour during the fall and winter incubation period.

Bean, J. R.; Wilcox, A. C.; Woessner, W. W.; Muhlfeld, C.

2013-12-01

293

Influence of life-history variation on the genetic structure of two sympatric salamander taxa.  

PubMed

Life-history characteristics are an important determinant of a species' dispersal abilities. We predict that variation in life history can influence population-level genetic patterns. To test this prediction, we estimate population-level genetic structure for two sympatric species of stream-breeding salamander. The Cope's giant salamander (Dicamptodon copei) rarely metamorphoses into a terrestrial adult, thereby limiting overland dispersal and potentially gene flow. In contrast, the Pacific giant salamander (D. tenebrosus) commonly metamorphoses, which is expected to facilitate overland dispersal and gene flow. Three sets of analyses based on microsatellite data support these hypotheses, showing that D. tenebrosus displays minimal population-level genetic structuring and no pattern of isolation by distance, whereas D. copei displays a high degree of population-level genetic structure and significant isolation by distance. Specifically, nearly all pairwise F(ST )values were significantly different from 0 between populations of D. copei, with fewer than half the pairwise F(ST )values significant from 0 in D. tenebrosus. Additionally, Structure analyses indicated eight genetic clusters for D. copei but only one genetic cluster for D. tenebrosus. Finally, Mantel tests showed significant correlations between stream and overland distance with genetic distance for D. copei but no significant correlations of either landscape feature for D. tenebrosus at the scale of the study. These results provide a case study of the link between life-history variation and population genetic patterns while controlling for phylogeny and environmental variation. PMID:19302353

Steele, C A; Baumsteiger, J; Storfer, Andrew

2009-04-01

294

Detection and Influence of Shrinkage Pores and Nonmetallic Inclusions on Fatigue Life of Cast Aluminum Alloys  

NASA Astrophysics Data System (ADS)

In the current study, test bars of cast aluminum alloys EN AC-AlSi8Cu3 and EN AC-AlSi7Mg0.3 were produced with a defined amounts of shrinkage pores and oxides. For this purpose, a permanent mold with heating and cooling devices for the generation of pores was constructed. The oxides were produced by contaminating the melt. The specimens and their corresponding defect distributions were examined and quantified by X-ray computer tomography (CT) and quantitative metallography, respectively. A special test algorithm for the simultaneous image analyses of pores and oxides was developed. Fatigue tests were conducted on the defective samples. It was found that the presence of shrinkage pores lowers the fatigue strength, and only few oxide inclusions were found to initiate fatigue cracks when shrinkage pores are present. The results show that the pore volume is not sufficient to characterize the influence of shrinkage pores on fatigue life. A parametric model for the calculation of fatigue life based on the pore parameters obtained from CT scans was implemented. The model accounts for the combined impact of pore location, size, and shape on fatigue life reduction.

Tijani, Yakub; Heinrietz, André; Stets, Wolfram; Voigt, Patrick

2013-12-01

295

The influence of early exposure to vitamin D for development of diseases later in life  

PubMed Central

Background Vitamin D deficiency is common among otherwise healthy pregnant women and may have consequences for them as well as the early development and long-term health of their children. However, the importance of maternal vitamin D status on offspring health later in life has not been widely studied. The present study includes an in-depth examination of the influence of exposure to vitamin D early in life for development of fractures of the wrist, arm and clavicle; obesity, and type 1 diabetes (T1D) during child- and adulthood. Methods/design The study is based on the fact that in 1961 fortifying margarine with vitamin D became mandatory in Denmark and in 1972 low fat milk fortification was allowed. Apart from determining the influences of exposure prior to conception and during prenatal life, we will examine the importance of vitamin D exposure during specific seasons and trimesters, by comparing disease incidence among individuals born before and after fortification. The Danish National databases assure that there are a sufficient number of individuals to verify any vitamin D effects during different gestation phases. Additionally, a validated method will be used to determine neonatal vitamin D status using stored dried blood spots (DBS) from individuals who developed the aforementioned disease entities as adults and their time and gender-matched controls. Discussion The results of the study will contribute to our current understanding of the significance of supplementation with vitamin D. More specifically, they will enable new research in related fields, including interventional research designed to assess supplementation needs for different subgroups of pregnant women. Also, other health outcomes can subsequently be studied to generate multiple health research opportunities involving vitamin D. Finally, the results of the study will justify the debate of Danish health authorities whether to resume vitamin D supplementation policies. PMID:23714352

2013-01-01

296

The use of habitat mosaics by terrestrial vertebrate fauna: implications for conservation and management  

Microsoft Academic Search

Many species of vertebrates require multiple habitats to obtain different resources at different stages of their life-cycles. Use of habitat mosaics takes place on a variety of spatial and temporal scales, from a daily requirement for adjacent habitats to seasonal use of geographically separated environments. Mosaics of habitats are also required in some species to allow ontogenetic habitat shifts, while

B. S. LAW; C. R. DICKMAN

1998-01-01

297

Behavioral, Physiologic, and Habitat Influences on the Dynamics of Puumala virus Infection in Bank Voles (Clethrionomys glareolus)  

PubMed Central

Populations of bank voles (Clethrionomys glareolus) were monitored during a 4-year study in southern Belgium to assess the influence of agonistic behavior, reproductive status, mobility, and distribution of the rodents on the dynamics of Puumala virus (abbreviation: PUUV; genus: Hantavirus) infection. Concordance was high between data from serologic testing and results of viral RNA detection. Wounds resulting from biting or scratching were observed mainly in adult rodents. Hantavirus infection in adults was associated with wounds in the fall, i.e., at the end of the breeding season, but not in spring. In addition, sexually active animals were significantly more often wounded and positive for infection. Hantavirus infection was associated with higher mobility in juvenile and subadult males. Seroconversions observed 6 months apart also occurred more frequently in animals that had moved longer distances from their original capture point. During nonepidemic years, the distribution of infection was patchy, and positive foci were mainly located in dense ground vegetation. PMID:12194769

Chalon, Patrice; de Jaegere, Florence; Karelle-Bui, Lucie; Mees, Georges; Brochier, Bernard; Rozenfeld, Francine; Pastoret, Paul-Pierre

2002-01-01

298

Effects of water management, connectivity, and surrounding land use on habitat use by frogs in rice paddies in Japan.  

PubMed

In Japan, rice paddies play an important role as a substitute habitat for wetland species, and support rich indigenous ecosystems. However, since the 1950s, agricultural modernization has altered the rice paddy environment, and many previously common species are now endangered. It is urgently necessary to evaluate rice paddies as habitats for conservation. Among the species living in rice paddies, frogs are representative and are good indicator species, so we focused on frog species and analyzed the influence of environmental factors on their habitat use. We found four frog species and one subspecies (Hyla japonica, Pelophylax nigromaculatus, Glandirana rugosa, Lithobates catesbeianus, and Pelophylax porosa brevipoda) at our study sites in Shiga prefecture. For all but L. catesbeianus, we analyzed the influence of environmental factors related to rice paddy structure, water management and availability, agrochemical use, connectivity, and land use on breeding and non-breeding habitat use. We constructed generalized additive mixed models with survey date as the smooth term and applied Akaike's information criterion to choose the bestranked model. Because life histories and biological characteristics vary among species, the factors affecting habitat use by frogs are also expected to differ by species. We found that both breeding and non-breeding habitat uses of each studied species were influenced by different combinations of environmental factors and that in most cases, habitat use showed seasonality. For frog conservation in rice paddies, we need to choose favorable rice paddy in relation to surrounding land use and apply suitable management for target species. PMID:22943781

Naito, Risa; Yamasaki, Michimasa; Lmanishi, Ayumi; Natuhara, Yosihiro; Morimoto, Yukihiro

2012-09-01

299

How Does Chronic Back Pain Influence Quality of Life in Koreans: A Cross-Sectional Study  

PubMed Central

Study Design A cross-sectional study. Purpose To explore the impact of chronic low back pain (CLBP) on individuals' quality of life; to understand current treatment practices and level of satisfaction with treatment in patients with CLBP. Overview of Literature Assessing subjective, patient-reported outcomes such as quality of life is essential to health care research. Methods Influences of the CLBP were analyzed via a questionnaire, which contained the character of CLBP, effect of pain management, Korean version Oswestry Disability Index (K-ODI) and Korean version of 12-item Short Form Health Survey (SF-12v2). Results Of 3,121 subjects who responded, 67.3% had moderate to severe pain; 43.5% presented prolonged CLBP of more than two years; and 32.4% had suffered from sleep disturbance due to pain. 22.8% of the patients were not satisfied with current pain management. The mean K-ODI score was 37.63; and it was positively correlated with the mean pain intensity (r=0.6, p<0.001). The SF-12v2 result was negatively correlated with mean pain intensity (PCS: r=-0.5, p<0.001; MCS: r=-0.4, p<0.001) and also negatively correlated with the K-ODI score (PCS: r=-0.75, p<0.001; MCS: r=-0.5, p<0.001). The conformity between patients and doctors in pain assessment was fair (?=0.2463). Conclusions CLBP negatively affects quality of life. Of total 22.8% of the patients were not satisfied with current pain management. Such needs to be taken more seriously by doctors for improvement of satisfaction and quality of life in patients with CLBP. PMID:24967049

Choi, Yong Soo; Kim, Dong Jun; Lee, Kyu Yeol; Park, Ye Soo; Cho, Kyu Jung; Lee, Jae Hyup; Rhim, Hyou Young

2014-01-01

300

When Giants Turn Up: Sighting Trends, Environmental Influences and Habitat Use of the Manta Ray Manta alfredi at a Coral Reef  

PubMed Central

Manta rays Manta alfredi are present all year round at Lady Elliot Island (LEI) in the southern Great Barrier Reef, Australia, with peaks in abundance during autumn and winter. Drivers influencing these fluctuations in abundance of M. alfredi at the site remain uncertain. Based on daily count, behavioural, weather and oceanographic data collected over a three-year period, this study examined the link between the relative number of sightings of manta rays at LEI, the biophysical environment, and the habitat use of individuals around the LEI reef using generalised additive models. The response variable in each of the three generalised additive models was number of sightings (per trip at sea) of cruising, cleaning or foraging M. alfredi. We used a set of eleven temporal, meteorological, biological, oceanographic and lunar predictor variables. Results for cruising, cleaning and foraging M. alfredi explained 27.5%, 32.8% and 36.3% of the deviance observed in the respective models and highlighted five predictors (year, day of year, wind speed, chlorophyll-a concentration and fraction of moon illuminated) as common influences to the three models. There were more manta rays at LEI in autumn and winter, slower wind speeds, higher productivity, and around the new and full moon. The winter peak in sightings of foraging M. alfredi was found to precede peaks in cleaning and cruising activity around the LEI reef, which suggests that enhanced food availability may be a principal driver for this seasonal aggregation. A spatial analysis of behavioural observations highlighted several sites around the LEI reef as ‘multi-purpose’ areas where cleaning and foraging activities commonly occur, while the southern end of the reef is primarily a foraging area. The use of extensive citizen science datasets, such as those collected by dive operators in this study, is encouraged as they can provide valuable insights into a species' ecology. PMID:23056255

Jaine, Fabrice R. A.; Couturier, Lydie I. E.; Weeks, Scarla J.; Townsend, Kathy A.; Bennett, Michael B.; Fiora, Kym; Richardson, Anthony J.

2012-01-01

301

Foraging requirements of the endangered long-fingered bat: the influence of micro-habitat structure, water quality and prey type  

Microsoft Academic Search

Myotis capaccinii is one of the most endangered Mediterranean bats. We radio tracked 21 adult individuals to assess foraging range and analyse micro-habitat selection around a nursery roost in central Italy. Habitats were characterized by development of riparian vegetation, distance between banks, degree of water clutter and levels of water pollution (expressed by macro-benthic bioindicators). Diet was also analysed to

S. Biscardi; D. Russo; V. Casciani; D. Cesarini; M. Mei; L. Boitani

2007-01-01

302

Woody debris, voles, and trees: Influence of habitat structures (piles and windrows) on long-tailed vole populations and feeding damage  

Microsoft Academic Search

Coarse woody debris (CWD) has many ecological functions ranging from conservation of biodiversity to long-term ecosystem productivity. Wildlife habitat, in particular, has been the focus of CWD investigations aimed at maintaining mammal species in managed forests. Piles and windrows of post-harvest woody debris could be designed to provide connectivity and habitat across clearcut openings for a wide array of mammalian

Thomas P. Sullivan; Druscilla S. Sullivan

303

Influence of Bovine Slurry Deposition on the Structure of Nodulating Rhizobium leguminosarum bv. viciae Soil Populations in a Natural Habitat  

PubMed Central

The population of nodulating R. leguminosarum bv. viciae in soil from a grass-covered valley area which had been used for bovine slurry deposition over a period of 5 years was analyzed. For these studies, a rapid and reproducible method based on enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to identify Rhizobium strains which had infected pea nodules. Soil samples were taken from different areas and further analyzed in plant tests to determine the impact of the application of slurry (polluted or nonpolluted), the slope position (summit or toe), and exposure (north or south). After comparison of all PCR fingerprint patterns, 24 strain groups were defined. Some strain groups from the nonpolluted soil were suppressed in the polluted samples, and new strain groups were detected in the slurry-polluted soil. After analyzing relationships between the strain groups, we determined the influences of local factors on the nodulating R. leguminosarum bv. viciae population. We show that one of those local parameters, slope position, had significantly greater impact on the composition of the Rhizobium population than the presence of slurry. PMID:16535318

Labes, G.; Ulrich, A.; Lentzsch, P.

1996-01-01

304

Interactions between habitat heterogeneity and food affect reproductive output in a top predator.  

PubMed

1. Habitat heterogeneity has important repercussions for species abundance, demography and life-history patterns. While habitat effects have been more thoroughly studied in top-down situations (e.g. in association with predation), their role in bottom-up situations (e.g. in association with food abundance) has been less explored and the underlying mechanism(s) behind the ecological patterns have not commonly been identified. 2. With material from 1993 to 2003, we test the hypothesis that the reproduction of Finnish northern goshawks Accipiter gentilis (L.) is bottom-up limited by habitat composition, especially in situations where the density of their main prey (grouse) is low. Special emphasis was placed on identifying the mechanism(s) behind potential habitat effects. 3. While laying date and large-scale variation in the main prey density (but not habitat composition) were related to the number of eggs goshawks laid, small-scale differences in alternative prey density between different territories later influenced how many young were fledged via the mechanism of habitat-dependent partial-brood loss. As a result of this mechanism, a difference in nestling condition also arose between goshawk territories with differing habitat compositions. 4. As the relative proportions of different landscape elements in a given landscape is a function of large-scale differences in geomorphology and land use, this means that the reproductive performance of goshawks as averaged over larger scales can be understood correctly only in respect to the fact that habitat gradients differ across landscapes. 5. In addition to being one of the first papers identifying the mechanism of partial brood loss as being primarily responsible for the habitat-specific differences in the production of young, this study further illustrates the need to identify small-scale mechanisms to correctly understand the large-scale patterns of reproductive performance in territorial species. The repercussions of the observed habitat effect for local population development are discussed. PMID:17302847

Byholm, Patrik; Nikula, Ari; Kentta, Jussi; Taivalmäki, Jukka-Pekka

2007-03-01

305

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

306

Habitat quality affects early physiology and subsequent neuromotor development of juvenile black-capped chickadees.  

PubMed

In songbirds, the ability to learn and render the species-specific song is influenced by the development of both the song nuclei in the brain and the syrinx (bird's vocal apparatus) early in the bird's life. In black-capped chickadees (Poecille atricapillus), habitat quality is known to affect song structure, with birds in high-quality habitat (mature forest) having a higher song consistency than birds in low-quality habitat (young forest). Although this difference is suspected to stem from differences in development, the developmental status of juvenile birds in either habitat remains unexplored. In this study, we used ptilochronology and feather corticosterone to compare the conditional state of juvenile chickadees in young and mature forest during two distinct periods of song learning - the sensory phase, which occurs prior to settlement, and the sensorimotor phase, which occurs post-settlement. A sample of juvenile males was captured and euthanized several weeks prior to their first breeding season to compare the development of song center nuclei and syrinx in both habitats. The corticosterone levels of natally-grown feathers were greater among birds that settled in mature than young forests - as these feathers were grown pre-settlement, they reflect differences in physiology during the sensory phase. This difference in conditional state is reflected by differences in syrinx and song center nuclei development later during the sensorimotor phase - birds in young forest have smaller syrinx, and moderately-larger RA, than birds in mature forest. Those differences could be responsible for the difference in consistency in song structure observed across habitats. The difference in physiological state across habitats, combined with potential compounding effect of differences in winter resources between habitats, could influence the difference in syrinx and neural development seen in juvenile males during the early spring, and influence the male's ability to learn and render their species-specific song. PMID:23951257

Grava, Thibault; Fairhurst, Graham D; Avey, Marc T; Grava, Angelique; Bradley, James; Avis, Jillian L; Bortolotti, Gary R; Sturdy, Christopher B; Otter, Ken A

2013-01-01

307

Habitat Quality Affects Early Physiology and Subsequent Neuromotor Development of Juvenile Black-Capped Chickadees  

PubMed Central

In songbirds, the ability to learn and render the species-specific song is influenced by the development of both the song nuclei in the brain and the syrinx (bird's vocal apparatus) early in the bird's life. In black-capped chickadees (Poecille atricapillus), habitat quality is known to affect song structure, with birds in high-quality habitat (mature forest) having a higher song consistency than birds in low-quality habitat (young forest). Although this difference is suspected to stem from differences in development, the developmental status of juvenile birds in either habitat remains unexplored. In this study, we used ptilochronology and feather corticosterone to compare the conditional state of juvenile chickadees in young and mature forest during two distinct periods of song learning - the sensory phase, which occurs prior to settlement, and the sensorimotor phase, which occurs post-settlement. A sample of juvenile males was captured and euthanized several weeks prior to their first breeding season to compare the development of song center nuclei and syrinx in both habitats. The corticosterone levels of natally-grown feathers were greater among birds that settled in mature than young forests - as these feathers were grown pre-settlement, they reflect differences in physiology during the sensory phase. This difference in conditional state is reflected by differences in syrinx and song center nuclei development later during the sensorimotor phase - birds in young forest have smaller syrinx, and moderately-larger RA, than birds in mature forest. Those differences could be responsible for the difference in consistency in song structure observed across habitats. The difference in physiological state across habitats, combined with potential compounding effect of differences in winter resources between habitats, could influence the difference in syrinx and neural development seen in juvenile males during the early spring, and influence the male's ability to learn and render their species-specific song. PMID:23951257

Grava, Thibault; Fairhurst, Graham D.; Avey, Marc T.; Grava, Angelique; Bradley, James; Avis, Jillian L.; Bortolotti, Gary R.; Sturdy, Christopher B.; Otter, Ken A.

2013-01-01

308

Workaholism and work-life imbalance: does cultural origin influence the relationship?  

PubMed

In recent years, workaholism has become prevalent throughout organizations and has captured the attention of organizational leaders as well as the academic and scientific communities. Most research in this area has focused on the negative consequences of workaholism, specifically work-life imbalance. One area of research that has largely been ignored is the potential influence of demographic variables on the relationship between workaholism and work-life imbalance. Therefore, the current study focused on how cultural origin might influence the intensity of this relationship. Based on relative deprivation theory and previous empirical work, it was expected that cultural origin would moderate the relationship between workaholism and work-life imbalance. Specifically, it was predicted that Caucasian participants would score higher on levels of workaholism than Black participants, and that the relationship between workaholism and work-life imbalance would be stronger for Caucasians than for Blacks. The results revealed that high levels of workaholism were significantly correlated with high levels of work-life imbalance. However, results also indicated that cultural origin did not moderate the relationship between workaholism and work-life imbalance, and there was no significant mean difference between Caucasian and Black participants on our measure of workaholism. These findings are important in that it is essential for employers to be aware of workaholic tendencies so they can better handle the negative consequences that result for the organization, and to also help promote the well-being of their employees. En los últimos años la adicción al trabajo se ha vuelto muy popular en las organizaciones y ha capturado la atención tanto de líderes organizacionales, así como de las comunidades científicas y académicas. La mayoría de investigaciones en esta área se han focalizado en las consequencias negativas de la adicción al trabajo (workoholismo), específicamente en el desequilibrio entre trabajo-vida. Una área de investigación que ha sido ignorada por mucho tiempo es la influencia potencial de las variables demográficas sobre la relación entre adicción al trabajo y el desequilibrio trabajo-vida. Por este motivo es que el presente estudio se focalizó en como el origen cultural puede influenciar la intensidad de esta relación. Tomando como base la teoría de la deprivación relativa y estudios empíricos previos, se esperó que el origen cultural moderaría la relación entre adicción al trabajo y desequilibrio trabajo-vida. Específicamente se pudo predecir que los participantes caucásicos mostraron más elevados puntajes en los niveles de adicción al trabajo que los participantes negros, y que la relación entre adicción al trabajo y desequilibrio trabajo-vida era más intensa entre los caucásicos que entre los negros. Los resultados revelaron que elevados niveles de adicción al trabajo correlacionaron significativamente con altos niveles de desequilibrio trabajo-vida. Sin embargo los resultados también revelaron que el origen cultural no moderaba la relación entre adicción al trabajo y desequilibrio trabajo-vida, y que además no había una diferencia significativa de medias entre los participantes caucásicos y negros respecto de nuestras mediciones de adicción al trabajo. Estos resultados son importantes en la medida en que es esencial para los empleadores el ser conscientes respecto de las tendencias de adicción al trabajo, lo que les permitirá manejar con mayor efectividad las consequencias negativas para la empresa resultantes de estas tendencias, y por otro lado apoyar a sus empleados en la promoción de su bienestar. Au cours des dernières années, le travaillolisme (workaholism) a pris de l'ampleur dans les organisations et a capté l'attention à la fois des dirigeants d'organisations et des communautés académique et scientifique. La majorité de la recherche dans ce domaine fut orientée sur les conséquences négatives du travaillolisme et, plus spécifiquement, sur le conflit travai

Aziz, Shahnaz; Adkins, Carrie T; Walker, Alan G; Wuensch, Karl L

2010-02-01

309

Do Maternal Quality of Life and Breastfeeding Difficulties Influence the Continuation of Exclusive Breastfeeding?  

PubMed Central

Objectives. This study was conducted to determine whether maternal quality of life (QOL) and breastfeeding difficulties influence the continuation of exclusive breastfeeding (EBF). Methods. In a survey, 358 consecutive pregnant women filled out a quality of life questionnaire in the third trimester of pregnancy and the breastfeeding experience scale at 4 weeks postpartum. We assessed breastfeeding practices every month up to 6 months postpartum. Results. Only 11.8% of women continued EBF at six months. Mothers who continued EBF at 2 and 4 months postpartum had better QOL in late pregnancy than mothers who discontinued it (P < 0.05). There were no significant differences between the two groups in QOL scores at 6 months postpartum. Mothers who continued EBF at 2 months postpartum experienced less breastfeeding difficultties during one month postpartum than mothers who discontinued it (P < 0.05). Conclusion. In attempts to promote EBF, mothers with poor QOL or breastfeeding difficulties in early postpartum should be identified and helped. PMID:24868209

Mousavi, Seyed Abbas; Chaman, Reza; Khosravi, Ahmad

2014-01-01

310

Evidence that Life History Characteristics of Wild Birds Influence Infection and Exposure to Influenza A Viruses  

PubMed Central

We report on life history characteristics, temporal, and age-related effects influencing the frequency of occurrence of avian influenza (AI) viruses in four species of migratory geese breeding on the Yukon-Kuskokwim Delta, Alaska. Emperor geese (Chen canagica), cackling geese (Branta hutchinsii), greater white-fronted geese (Anser albifrons), and black brant (Branta bernicla), were all tested for active infection of AI viruses upon arrival in early May, during nesting in June, and while molting in July and August, 2006–2010 (n?=?14,323). Additionally, prior exposure to AI viruses was assessed via prevalence of antibodies from sera samples collected during late summer in 2009 and 2010. Results suggest that geese are uncommonly infected by low pathogenic AI viruses while in Alaska. The percent of birds actively shedding AI viruses varied annually, and was highest in 2006 and 2010 (1–3%) and lowest in 2007, 2008, and 2009 (<0.70%). Contrary to findings in ducks, the highest incidence of infected birds was in late spring when birds first arrived from staging and wintering areas. Despite low prevalence, most geese were previously exposed to AI viruses, as indicated by high levels of seroprevalence during late summer (47%–96% across species; n?=?541). Seroprevalence was >95% for emperor geese, a species that spends part of its life cycle in Asia and is endemic to Alaska and the Bering Sea region, compared to 40–60% for the other three species, whose entire life cycles are within the western hemisphere. Birds <45 days of age showed little past exposure to AI viruses, although antibodies were detected in samples from 5-week old birds in 2009. Seroprevalence of known age black brant revealed that no birds <4 years old had seroconverted, compared to 49% of birds ?4 years of age. PMID:23469210

Ely, Craig R.; Hall, Jeffrey S.; Schmutz, Joel A.; Pearce, John M.; Terenzi, John; Sedinger, James S.; Ip, Hon S.

2013-01-01

311

Evidence that life history characteristics of wild birds influence infection and exposure to influenza A viruses.  

PubMed

We report on life history characteristics, temporal, and age-related effects influencing the frequency of occurrence of avian influenza (AI) viruses in four species of migratory geese breeding on the Yukon-Kuskokwim Delta, Alaska. Emperor geese (Chen canagica), cackling geese (Branta hutchinsii), greater white-fronted geese (Anser albifrons), and black brant (Branta bernicla), were all tested for active infection of AI viruses upon arrival in early May, during nesting in June, and while molting in July and August, 2006-2010 (n?=?14,323). Additionally, prior exposure to AI viruses was assessed via prevalence of antibodies from sera samples collected during late summer in 2009 and 2010. Results suggest that geese are uncommonly infected by low pathogenic AI viruses while in Alaska. The percent of birds actively shedding AI viruses varied annually, and was highest in 2006 and 2010 (1-3%) and lowest in 2007, 2008, and 2009 (<0.70%). Contrary to findings in ducks, the highest incidence of infected birds was in late spring when birds first arrived from staging and wintering areas. Despite low prevalence, most geese were previously exposed to AI viruses, as indicated by high levels of seroprevalence during late summer (47%-96% across species; n?=?541). Seroprevalence was >95% for emperor geese, a species that spends part of its life cycle in Asia and is endemic to Alaska and the Bering Sea region, compared to 40-60% for the other three species, whose entire life cycles are within the western hemisphere. Birds <45 days of age showed little past exposure to AI viruses, although antibodies were detected in samples from 5-week old birds in 2009. Seroprevalence of known age black brant revealed that no birds <4 years old had seroconverted, compared to 49% of birds ?4 years of age. PMID:23469210

Ely, Craig R; Hall, Jeffrey S; Schmutz, Joel A; Pearce, John M; Terenzi, John; Sedinger, James S; Ip, Hon S

2013-01-01

312

Influence of stream habitat and land use on benthic macroinvertebrate indicators of stream quality of selected above-tidal streams in the Houston-Galveston Area Council service area, Texas, 1997-98  

USGS Publications Warehouse

During 1997?98, the U.S. Geological Survey, in cooperation with the Houston-Galveston Area Council, collected stream-habitat and benthic macroinvertebrate data for 31 reaches on above-tidal streams in the Council service area near Houston, Texas. Stream-habitat, land-use and population, and benthic aquatic insect metrics were determined for the 31 reaches. Statistical analyses were used to determine the stream-habitat, land-use and population, and aquatic insect variables that are strongly intercorrelated and that explain the greatest amount of variation between the reaches. Comparison of stream-habitat and biological integrity scores computed for each of the 31 reaches indicated (1) reaches generally had larger stream-habitat integrity scores in drainage areas that were heavily forested and had fewer people per square mile, (2) larger biological integrity scores were significantly correlated with larger stream-habitat integrity scores, and (3) urban reaches generally had more simplified stream-habitat conditions and smaller biological integrity scores. Seven reaches in the study area were selected as reference reaches on the basis of high stream-habitat integrity and high biological integrity. The reference-reaches median biological integrity score was equaled or exceeded by three reaches (one on Spring Creek and two on Cypress Creek) that are on the State of Texas 303(d) list of threatened or impaired waters with respect to aquatic life. This indicates that direct measures of biological integrity could be used to supplement surrogate-based designations of biological integrity such as the State list. A statistically significant multiple-regression model was developed that uses independent variables that can be obtained without field-intensive studies to predict the biological integrity score for a reach. The deviation from the model?s predicted score with the score based on biological sampling can be used to interpret the degree of biological impairment in a reach. Data from reaches outside the group of reaches used in this study are needed to test the validity of the multiple-regression model.

Moring, J. Bruce

2001-01-01

313

The influence of developmental life stage on quality of life in survivors of prostate cancer and their partners  

Microsoft Academic Search

Introduction  Although prostate cancer is prevalent, little information is available on how it affects couples’ quality of life (QOL) according\\u000a to their age cohort. The purpose of this study was to examine how quality of life, self-efficacy and appraisal of the illness\\u000a experience vary among men with prostate cancer and their partners according to age cohort: middle age (50–64); young-old (65–74);

Janet Harden; Laurel Northouse; Bernadine Cimprich; Joanne M. Pohl; Jersey Liang; Trace Kershaw

2008-01-01

314

Lunar and Planetary Bases, Habitats, and Colonies  

NASA Technical Reports Server (NTRS)

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 systems.

2004-01-01

315

PROGRAM TO ASSIST IN TRACKING CRITICAL HABITAT  

EPA Science Inventory

PATCH is a spatially explicit, individual-based, life history simulator designed to project populations of territorial terrestrial vertebrate species through time. PATCH is ideal for investigations involving wildlife species that are mobile habitat specialists. PATCH's data req...

316

Life  

NSDL National Science Digital Library

Run the classic game of life, learning about probabilities, chaos and simulation. This activity allows the user to run a randomly generated world or test out various patterns. This is a very powerful activity with a wide range of options. It runs in a separate window.

317

Variables influencing quality of life and disability in Charcot Marie Tooth (CMT) patients: Italian multicentre study.  

PubMed

The purpose of this study was to assess the variables that influence quality of life (QoL) and disability in patients with Charcot-Marie-Tooth disease (CMT). We performed a prospective multicentre study using validated clinical disability and QoL measurements. Multivariate analysis was performed using QoL as a dependent variable and duration of symptoms, age, gender and CMT type, depression and disability measurements as independent variables. We enrolled 211 patients. QoL was highly significantly deteriorated with respect to the Italian normative sample. The physical aspect of QoL was mainly related to disability but it does not increase with the age, probably because of an adaptation between expectation and reality. The mental QoL is influenced by depression (hence we have to consider this aspect approaching CMT patients). Moreover, we observed that women complained of more severe symptoms than men. Finally, some CMT subtypes are related to more severe bodily pain symptoms than others. Multiperspective assessment of CMT showed new aspects of this disease, mainly regarding (1) differences between men and women and (2) the crucial role of pain and depression. PMID:17205227

Padua, L; Aprile, I; Cavallaro, T; Commodari, I; La Torre, G; Pareyson, D; Quattrone, A; Rizzuto, N; Vita, G; Tonali, P; Schenone, A

2006-12-01

318

Alcohol Response and Consumption in Adolescent Rhesus Macaques: Life History and Genetic Influences  

PubMed Central

The use of alcohol by adolescents is a growing problem and has become an important research topic in the etiology of the alcohol use disorders. A key component of this research has been the development of animal models of adolescent alcohol consumption and alcohol response. Due to their extended period of adolescence, rhesus macaques are especially well-suited for modeling alcohol-related phenotypes that contribute to the adolescent propensity for alcohol consumption. In this review, we discuss studies from our laboratory that have investigated both the initial response to acute alcohol administration and the consumption of alcohol in voluntary self-administration paradigms in adolescent rhesus macaques. These studies confirm that adolescence is a time of dynamic change both behaviorally and physiologically, and that alcohol response and alcohol consumption are influenced by life history variables such as age, sex, and adverse early experience in the form of peer-rearing. Furthermore, genetic variants that alter functioning of the serotonin, endogenous opioid, and corticotropin releasing hormone systems are shown to influence both physiological and behavioral outcomes, in some cases interacting with early experience to indicate gene by environment interactions. These findings highlight several of the pathways involved in alcohol response and consumption, namely reward, behavioral dyscontrol, and vulnerability to stress, and demonstrate a role for these pathways during the early stages of alcohol exposure in adolescence. PMID:20113875

Schwandt, Melanie L.; Lindell, Stephen G.; Chen, Scott; Higley, J. Dee; Suomi, Stephen J.; Heilig, Markus; Barr, Christina S.

2009-01-01

319

Growth history and intrinsic factors influence risk assessment at a critical life transition for a fish  

NASA Astrophysics Data System (ADS)

Making the appropriate decision in the face of predation risk dictates the fate of prey, and predation risk is highest at life history boundaries such as settlement. At the end of the larval phase, most coral reef fishes enter patches of reef containing novel predators. Since vision is often obscured in the complex surroundings, chemical information released from damaged conspecific is used to forewarn prey of an active predator. However, larvae enter the reef environment with their own feeding and growth histories, which will influence their motivation to feed and take risks. The present study explored the link between recent growth, feeding history, current performance and behavioural risk taking in newly settling stages of a coral reef damselfish ( Pomacentrus amboinensis). Older and larger juveniles in good body condition had a stronger response to chemical alarm cues of injured conspecifics; these fish spent a longer time in shelter and displayed a more dramatic decrease in foraging behaviour than fish in lower body condition. Feeding experiments supported these findings and emphasized the importance of body condition in affecting risk assessment. Evidently, larval growth history and body condition influences the likelihood of taking risks under the threat of predation immediately after settlement, thereby affecting the probability of survival in P. amboinensis.

Lönnstedt, O. M.; McCormick, M. I.

2011-09-01

320

Influence of caregiving on health-related quality of life among American Indians.  

PubMed

Caregiving can have a profound effect on the health of the caregiver, yet research on caregiving among American Indians is limited. The purpose of this study was to examine the influence of caregiving on the health-related quality of life (HRQoL) of American Indians enrolled in the Education And Research Towards Health (EARTH) study. Participants in the EARTH study represented three different tribes in the Northern Plains and Southwestern regions of the United States who completed self-administered, computer-assisted questionnaires between 2003 and 2006. Participants were classified as caregivers if at least one adult relied on them for personal care or as non-caregivers (n = 3,736). Caregivers were further classified according to type; those caring for an adult with unspecified needs (CAU, n = 482) and those caring for an adult with mental or physical difficulties (CAD, n = 295). HRQoL was measured using the mental and physical health component scores of the Medical Outcomes Study 12-item Short-Form Health Survey. Regional differences emerged with regard to caregiver type. Across both regions, non-caregivers reported significantly better mental and physical health than CAD, and the health of participants classified as CAU did not differ from that of non-caregivers. The health of American Indian caregivers depends on the kind of care provided, but detailed measures of caregiving are necessary to understand how caregiving influences health. This has implications for the design of effective interventions in tribal communities. PMID:24001320

Spencer, S Melinda; Goins, R Turner; Henderson, Jeffrey A; Wen, Yang; Goldberg, Jack

2013-09-01

321

ASSESSING THE EFFECT OF HABITAT ALTERATION ON SHELLFISH POPULATIONS  

EPA Science Inventory

Habitat provides a variety of life support functions for many species, such as providing shelter, substrate, food, and nursery areas. Habitat alteration is one of the most important causes of declines in ecological resources in North America, and habitats essential to the well b...

322

Influence of habitat dynamics on the distribution and abundance of the federally threatened Santa Ana Sucker, Catostomus santaanae , in the Santa Ana River  

Microsoft Academic Search

Habitat degradation affects native stream fish populations worldwide. We examined the impact of fluctuation in environmental\\u000a variables on the population dynamics of the federally threatened Santa Ana sucker, Catostomus santaanae, in the Santa Ana River, California through: 1) annual quantitative surveys of C. santaanae abundance and habitat at three 100-m sites between 2001 and 2008 and 2) annual surveys of

Andrew Richard Thompson; Jonathan N. Baskin; Camm C. Swift; Thomas R. Haglund; Randall J. Nagel

2010-01-01

323

Life history and habitat associations of the broad wood cockroach, Parcoblatta lata (Blattaria: Blattellidae) and other native cockroaches in the Coastal Plain of South Carolina.  

SciTech Connect

Wood cockroaches are an important prey of the red-cockaded woodpecker, Picoides borealis, an endangered species inhabiting pine forests in the southern United States. These woodpeckers forage on the boles of live pine trees, but their prey consists of a high proportion of wood cockroaches, Parcoblatta spp., that are more commonly associated with dead plant material. Cockroach population density samples were conducted on live pine trees, dead snags and coarse woody debris on the ground. The studies showed that snags and logs are also important habitats of wood cockroaches in pine forests.

Horn, Scott; Hanula, James, L.

2002-06-18

324

Habitat-specific foraging of prothonotary warblers: Deducing habitat quality  

USGS Publications Warehouse

Foraging behavior often reflects food availability in predictable ways. For example, in habitats where food availability is high, predators should attack prey more often and move more slowly than in habitats where food availability is low. To assess relative food availability and habitat quality, I studied the foraging behavior of breeding Prothonotary Warblers (Protonotaria citrea) in two forest habitat types, cypress-gum swamp forest and coastal-plain levee forest. I quantified foraging behavior with focal animal sampling and continuous recording during foraging bouts. I measured two aspects of foraging behavior: 1) prey attack rate (attacks per minute), using four attack maneuvers (glean, sally, hover, strike), and 2) foraging speed (movements per minute), using three types of movement (hop, short flight [???1 m], long flight [>1 m]). Warblers attacked prey more often in cypress-gum swamp forest than in coastal-plain levee forest. Foraging speed, however, was not different between habitats. I also measured foraging effort (% time spent foraging) and relative frequency of attack maneuvers employed in each habitat; neither of these variables was influenced by forest type. I conclude that Prothonotary Warblers encounter more prey when foraging in cypress-gum swamps than in coastal-plain levee forest, and that greater food availability results in higher density and greater reproductive success for birds breeding in cypress-gum swamp.

Lyons, J.E.

2005-01-01

325

Slipping through the cracks: rubber plantation is unsuitable breeding habitat for frogs in Xishuangbanna, China.  

PubMed

Conversion of tropical forests into agriculture may present a serious risk to amphibian diversity if amphibians are not able to use agricultural areas as habitat. Recently, in Xishuangbanna Prefecture, Yunnan Province - a hotspot of frog diversity within China - two-thirds of the native tropical rainforests have been converted into rubber plantation agriculture. We conducted surveys and experiments to quantify habitat use for breeding and non-breeding life history activities of the native frog species in rainforest, rubber plantation and other human impacted sites. Rubber plantation sites had the lowest species richness in our non-breeding habitat surveys and no species used rubber plantation sites as breeding habitat. The absence of breeding was likely not due to intrinsic properties of the rubber plantation pools, as our experiments indicated that rubber plantation pools were suitable for tadpole growth and development. Rather, the absence of breeding in the rubber plantation was likely due to a misalignment of breeding and non-breeding habitat preferences. Analyses of our breeding surveys showed that percent canopy cover over pools was the strongest environmental variable influencing breeding site selection, with species exhibiting preferences for pools under both high and low canopy cover. Although rubber plantation pools had high canopy cover, the only species that bred in high canopy cover sites used the rainforest for both non-breeding and breeding activities, completing their entire life cycle in the rainforest. Conversely, the species that did use the rubber plantation for non-breeding habitat preferred to breed in low canopy sites, also avoiding breeding in the rubber plantation. Rubber plantations are likely an intermediate habitat type that 'slips through the cracks' of species habitat preferences and is thus avoided for breeding. In summary, unlike the rainforests they replaced, rubber plantations alone may not be able to support frog populations. PMID:24040026

Behm, Jocelyn E; Yang, Xiaodong; Chen, Jin

2013-01-01

326

Slipping through the Cracks: Rubber Plantation Is Unsuitable Breeding Habitat for Frogs in Xishuangbanna, China  

PubMed Central

Conversion of tropical forests into agriculture may present a serious risk to amphibian diversity if amphibians are not able to use agricultural areas as habitat. Recently, in Xishuangbanna Prefecture, Yunnan Province – a hotspot of frog diversity within China – two-thirds of the native tropical rainforests have been converted into rubber plantation agriculture. We conducted surveys and experiments to quantify habitat use for breeding and non-breeding life history activities of the native frog species in rainforest, rubber plantation and other human impacted sites. Rubber plantation sites had the lowest species richness in our non-breeding habitat surveys and no species used rubber plantation sites as breeding habitat. The absence of breeding was likely not due to intrinsic properties of the rubber plantation pools, as our experiments indicated that rubber plantation pools were suitable for tadpole growth and development. Rather, the absence of breeding in the rubber plantation was likely due to a misalignment of breeding and non-breeding habitat preferences. Analyses of our breeding surveys showed that percent canopy cover over pools was the strongest environmental variable influencing breeding site selection, with species exhibiting preferences for pools under both high and low canopy cover. Although rubber plantation pools had high canopy cover, the only species that bred in high canopy cover sites used the rainforest for both non-breeding and breeding activities, completing their entire life cycle in the rainforest. Conversely, the species that did use the rubber plantation for non-breeding habitat preferred to breed in low canopy sites, also avoiding breeding in the rubber plantation. Rubber plantations are likely an intermediate habitat type that ‘slips through the cracks’ of species habitat preferences and is thus avoided for breeding. In summary, unlike the rainforests they replaced, rubber plantations alone may not be able to support frog populations. PMID:24040026

Behm, Jocelyn E.; Yang, Xiaodong; Chen, Jin

2013-01-01

327

Correlates of Life Style: Personality, Role Concept, Attitudes, Influences, and Choices  

Microsoft Academic Search

Using the California Psychological Inventory, the Inventory of Women's Life Styles, and the Inventory of Women's Role Concept and Attitudes, three separate life-style patterns were delineated for women leading Traditional, Neotraditional, and Nontraditional life styles. These women differed significantly in personality; role concepts; attitudes; choices of college majors and occupations; motivation; quality of employment experiences; parents' life styles; perceptions of

Agnes N. OConnell

1980-01-01

328

Habitat Demonstration Unit - Deep Space Habitat Configuration  

NASA Video Gallery

This animated video shows the process of transporting, assembling and testing the Habitat Demonstration Unit - Deep Space Habitat (HDU DSH) configuration, which will be deployed during the 2011 Des...

329

The Influence of Developmental Life Stage on Quality of Life In Survivors of Prostate Cancer and Their Partners  

PubMed Central

Introduction Although prostate cancer is prevalent, little information is available on how it affects couples’ quality of life (QOL) according to their age cohort. The purpose of this study was to examine how quality of life, self-efficacy and appraisal of the illness experience vary among men with prostate cancer and their partners according to age cohort: middle age (50–64); young-old (65–74); and old-old (75–84). Using an Adult Developmental and Family Stress framework, this study focuses on how normative (developmental stage) and non-normative stressors (prostate cancer) may affect a couple’s ability to adapt. Methods A descriptive, comparative design was used to examine age-related differences in quality of life and selected psychosocial variables in 69 men with prostate cancer and their spouses. Cross-sectional data were obtained using standardized instruments with adequate reliability and validity. ANCOVA and MANCOVA were used to determine differences among age groups. Results Findings indicated that patients who were ages 65–74 had better QOL and higher self-efficacy than patients ages 50–64 and less negative appraisal of illness than the other two groups. Spouses ages 50–64 reported the most distress related to sexual changes in their husbands. Spouses in both the middle age and old-old group had more bother related to hormone therapy than the young-old spouses. Implications for Cancer Survivors Findings suggest that interventions should be tailored to dyads’ developmental life stage. Younger and older prostate cancer survivors and their partners may benefit from tailored interventions designed to improve their quality of life and confidence in managing their treatment outcomes during the survivorship period. PMID:18648977

Harden, Janet; Northouse, Laurel; Cimprich, Bernadine; Pohl, Joanne M.; Liang, Jersey; Kershaw, Trace

2009-01-01

330

It's a Frog's Life  

NSDL National Science Digital Library

When a preschool teacher unexpectedly found tadpoles in the school's outdoor baby pool, she recognized an unusual opportunity for her students to study pond life up close. By following the tadpoles' development, students learned about frogs, life cycles, habitats.

Coffey, Audrey L.; Sterling, Donna R.

2003-09-01

331

The Influence of Ethnicity and Adverse Life Experiences during Adolescence on Young Adult Socioeconomic Attainment: The Moderating Role of Education  

ERIC Educational Resources Information Center

Previous research has documented that adverse life experiences during adolescence, particularly for ethnic minorities, have a long-term influence on income and asset attainment and that this relationship is largely mediated by educational achievement. We extend prior research by investigating three research questions. First, we investigate the…

Wickrama, K. A. S.; Simons, Leslie Gordon; Baltimore, Diana

2012-01-01

332

Gender in Cohabitation and Marriage: The Influence of Gender Ideology on Housework Allocation over the Life Course  

ERIC Educational Resources Information Center

The analysis examines the direct and indirect influences of early gender socialization on the allocation of routine housework later in the life course. The study articulates hypotheses suggesting that the relationship between gender socialization early in adulthood and housework allocation later in adulthood is moderated by gender and union type…

Cunningham, Mick

2005-01-01

333

INFLUENCE OF PRENATAL AND POSTNATAL EXPOSURE TO PASSIVE SMOKING ON INFANTS? HEALTH DURING THE FIRST SIX MONTHS OF THEIR LIFE  

Microsoft Academic Search

SUMMARY On the Czech set of European Longitudinal Study of Pregnancy and Childhood (ELSPAC), we tried to verify whether it is possible to confirm the results of foreign studies which found out that the both prenatal and postnatal exposure of newborns to chemicals on cigarette smoke could influence the newbornsmorbidity in the first six months of their life. Mothers, who

334

Influences of Children's and Adolescents' Action-Control Processes on School Achievement, Peer Relationships, and Coping with Challenging Life Events  

ERIC Educational Resources Information Center

Self-regulation represents a core aspect of human functioning that influences positive development across the life span. This chapter focuses on the action-control model, a key facet of self-regulation during childhood and early adolescence. The authors discuss the development of action-control beliefs, paying particular attention to their…

Geldhof, G. John; Little, Todd D.

2011-01-01

335

Identity Development of Gifted Female Adolescents: The Influence of Career Development, Age, and Life-Role Salience  

Microsoft Academic Search

In this study, the influence of career exploration and commitment, life-role salience, and chronological age on identity development in gifted female adolescents was examined. A set of factors, including vocational exploration and commitment, commitment to the role of work, and participation in the role of studying, explained 43.3% of the variance in the identity development of the gifted females who

Marie F. Shoffner; Deborah W. Newsome

2001-01-01

336

Factors influencing health-related quality of life of overweight and obese children in South Korea.  

PubMed

The purpose of this study was to identify factors influencing health-related quality of life (HRQoL) of overweight and obese children in Korea. This study employed a cross-sectional descriptive study design. A total of 132 overweight and obese children participated in the study. Anthropometric measurements included body mass index, percent body fat, and waist-hip ratio. The instruments included lifestyle patterns, psychosocial characteristics (stress, self-esteem, and depression), and HRQoL. The study found that significant predictors of HRQoL included self-esteem, depression, and physical stress; these variables accounted for 58.7% of the variance (p < .05), while children with low monthly household income had significantly lower HRQoL, compared with that of their counterparts (p < .05). HRQoL has multiple dimensions, thus, in addition to lifestyle change, health programs for overweight and obese children should focus on psychological health, and consider social and environmental factors as well. PMID:23401020

Kim, Hee Soon; Park, Jiyoung; Ma, Yumi; Ham, Ok Kyung

2013-10-01

337

A Quantitative Study of Factors Influencing Quality of Life in Rural Mexican Women Diagnosed With HIV.  

PubMed

This quantitative study explored the level of Quality of Life (QoL) in indigenous Mexican women and identified psychosocial factors that significantly influenced their QoL, using face-to-face interviews with 101 women accessing care in an HIV clinic in Oaxaca, Mexico. Variables included demographic characteristics, levels of depression, coping style, family functioning, HIV-related beliefs, and QoL. Descriptive statistics were used to analyze participant characteristics, and women's scores on data collection instruments. Pearson's R correlational statistics were used to determine the level of significance between study variables. Multiple regression analysis examined all variables that were significantly related to QoL. Pearson's correlational analysis of relationships between Spirituality, Educating Self about HIV, Family Functioning, Emotional Support, Physical Care, and Staying Positive demonstrated positive correlation to QoL. Stigma, depression, and avoidance coping were significantly and negatively associated with QoL. The final regression model indicated that depression and avoidance coping were the best predictor variables for QoL. PMID:24759058

Holtz, Carol; Sowell, Richard; VanBrackle, Lewis; Velasquez, Gabriela; Hernandez-Alonso, Virginia

2014-01-01

338

Scale-dependent habitat use in three species of prairie wetland birds  

Microsoft Academic Search

We evaluated the influence of scale on habitat use for three wetland-obligate bird species with divergent life history characteristics and possible scale-dependent criteria for nesting and foraging in South Dakota, USA. A stratified, two-stage cluster sample was used to randomly select survey wetlands within strata defined by region, wetland density, and wetland surface area. We used 18-m (0.1 ha) fixed radius

David E. Naugle; Kenneth F. Higgins; Sarah M. Nusser; W. Carter Johnson

1999-01-01

339

Survival of freezing by hydrated tardigrades inhabiting terrestrial and freshwater habitats.  

PubMed

The seasonality and unpredictability of environmental conditions at high altitudes and latitudes govern the life cycle patterns of organisms, giving rise to stresses that cause death or development of specific adaptations. Ice formation is a major variable affecting the survival of both freshwater fauna and fauna inhabiting lichens, mosses and leaf litter. Tardigrades occupy a wide range of niches in marine, freshwater and terrestrial environments. The highest number of species is found in terrestrial habitats thanks to their ability to enter anhydrobiosis and cryobiosis. The cryobiotic ability of tardigrade species from polar regions is well known. Consequently, we focused our research on the ability to survive freezing in the active hydrated state using seven tardigrade species differing in phylogenetic position and collected at various altitudes and from different habitats in a temperate area. Specimens were cooled at different cooling rates (from 0.31° C min(-1) to 3.26° C min(-1)). Even though the final survival and the time required by animals to recover to active life were both inversely related to the cooling rate, highly significant interspecific differences were found. Species survival ability ranged from excellent to none. Species living in xeric habitats withstood freezing better than those living in hygrophilous habitats, while true limnic species did not exhibit any cryobiotic ability. The ability to withstand freezing seems linked to the anhydrobiotic ability. The differences in cryptobiotic performance among tardigrade species seem more influenced by selective pressures linked to local adaptation to habitat characteristics than by phylogenetic relationships. PMID:21429723

Guidetti, Roberto; Altiero, Tiziana; Bertolani, Roberto; Grazioso, Pasqualina; Rebecchi, Lorena

2011-04-01

340

Habitat characteristics affecting fish assemblages on a Hawaiian coral reef  

Microsoft Academic Search

Habitat characteristics of a reef were examined as potential influences on fish assemblage structure, using underwater visual census to estimate numbers and biomass of all fishes visible on 42 benthic transects and making quantitative measurements of 13 variables of the corresponding physical habitat and sessile biota. Fish assemblages in the diverse set of benthic habitats were grouped by detrended correspondence

Alan M Friedlander; James D Parrish

1998-01-01

341

Toward an ecological synthesis: a case for habitat selection  

Microsoft Academic Search

Habitat selection, and its associated density and frequency-dependent evolution, has a profound influence on such vital phenomena as population regulation, species interactions, the assembly of ecological communities, and the origin and maintenance of biodiversity. Different strategies of habitat selection, and their importance in ecology and evolution, can often be revealed simply by plots of density in adjacent habitats. For individual

Douglas W. Morris

2003-01-01

342

Influences on Employee Perceptions of Organizational Work-Life Support: Signals and Resources  

ERIC Educational Resources Information Center

This study examined predictors of employee perceptions of organizational work-life support. Using organizational support theory and conservation of resources theory, we reasoned that workplace demands and resources shape employees' perceptions of work-life support through two mechanisms: signaling that the organization cares about their work-life

Valcour, Monique; Ollier-Malaterre, Ariane; Matz-Costa, Christina; Pitt-Catsouphes, Marcie; Brown, Melissa

2011-01-01

343

Channel dynamics and habitat complexity in a meandering, gravel-bed river  

NASA Astrophysics Data System (ADS)

River channel dynamics play an important role in creating and maintaining diverse habitat conditions for multiple life stages of aquatic organisms. As a result, many river restoration projects seek to re-establish ecosystems in which an enhanced degree of habitat complexity is sustained through natural fluvial processes of flow, sediment transport, and channel change. Few field cases have effectively quantified the evolution of channel morphology and habitat complexity in restored rivers, however, and the outcomes of restoration actions remain difficult to predict. Our objective was to quantify the extent to which morphology, flow complexity and salmonid spawning and rearing habitat develop from the simplified initial conditions commonly observed in re-configured meandering channels. Using a time-series of topographic data, we measured rates of morphologic change in a recently restored gravel-bed reach of the Merced River, California, USA. We constructed two-dimensional (2D) hydrodynamic models to quantify how the evolving morphology influenced hydraulic conditions, flow complexity and suitability for Chinook salmon spawning and rearing. Following two large flood events, point bar development led to order-of-magnitude increases in modeled flow complexity, as quantified via the metrics of kinetic energy gradient, vorticity and hydraulic strain. On a bend-averaged scale, morphologic changes produced up to a two-fold increase in flow circulation, indicating a direct linkage between geomorphic processes and the development of habitat complexity at both the local (1.0 m2 grid cell) and meander wavelength scale. Habitat modeling indicated that the availability of Chinook salmon spawning habitat has increased over time, whereas the majority of the reach provides low-medium quality rearing habitat for juvenile salmonids, primarily due to a lack of low velocity refuge zones. These results demonstrate the ability of geomorphic processes to increase flow complexity and enhance spawning habitat, yet there is little indication that morphological changes alone will create bioenergetically favorable conditions for juvenile salmonids in the absence of off-channel habitat and large wood. In order to better understand the relations between channel dynamics, flow complexity and individual fish performance at a given life stage, ongoing efforts are focused on using Dynamic Energy Budget theory to develop a mechanistic framework integrating information on the different salmon life stages with flow fields of varying complexity.

Harrison, L. R.; Legleiter, C. J.; Pecquerie, L.; Dunne, T.

2009-12-01

344

[Influence of ischemic heart disease mortality on the average life span in Bulgaria and economic results of this disease].  

PubMed

The paper provides a socio-economic evaluation of mortality from ischemic heart disease (IHD) in Bulgaria during 1983-1985. The influence of IHD on mean life expectancy at birth was determined by using concise methods. IHD shortens the mean life expectancy in urban areas by 2.4 years in boys and by 1.7 years in girls, in rural areas by 2.5 years in boys and by 1.2 in girls. Economic losses due to mortality from this disease were estimated. PMID:2057826

Nikolov, I N

1991-01-01

345

Influence of forage preferences and habitat use on C and N abundance in wild caribou (Rangifer tarandus caribou) and moose (Alces alces) from Canada  

Microsoft Academic Search

Stable isotope composition (?C and ?N) of moose (Alces alces) and caribou (Rangifer tarandus) hair from the boreal forest of Jacques-Cartier Park and Côte-Nord (Québec) and arctic tundra of Queen Maud Gulf and Southampton Island (Nunavut) was investigated as an indicator of dietary preferences and habitat use. Values of ?Chair and ?Nhair in moose were consistently lower compared to those

Dorothée G. Drucker; Keith A. Hobson; Jean-Pierre Ouellet; Réhaume Courtois

2010-01-01

346

Factors Influencing the Success of Riparian Planting Aspects of Fish Habitat Restoration Projects in the City of Surrey and Recommendations for Future Planting Plan Improvements  

Microsoft Academic Search

Long-term monitoring of fish habitat restoration projects undertaken in conjunction with municipal capital works projects in fulfillment of Fisheries and Oceans Canada (DFO) Section 35(2) Authorizations have been conducted for a significant period of time within the City of Surrey. The accumulated data have provided an opportunity to assess the reasons for success or failure of riparian planting work conducted

Tracy L. Anderson; Trevor R. Welton

2005-01-01

347

Fragmentation of habitats used by neotropical migratory birds in Southern Appalachians and the neotropics  

SciTech Connect

Recent declines in North American breeding populations have sparked great concern over the effects of habitat fragmentation. Neotropical migrant birds use and are influenced by two biomes during a single life span. Yet assessment of the relative importance of changes in tropical wintering areas versus temperate breeding areas is complicated by regional variation in rates and extent of habitat change. Landscape-level measurements of forest fragmentation derived from remotely-sensed data provide a means to compare the patterns of habitat modification on the wintering and breeding grounds of migrant birds. This study quantifies patterns of forest fragmentation in the Southern Appalachian Mountains and tropical Amazon and relates these patterns to the resource needs of neotropical migrant birds. Study sites were selected from remotely-sensed images to represent a range of forest fragmentation (highly fragmented landscape to continuous forest).

Pearson, S.M.; Dale, V.H. [Oak Ridge National Lab., TN (United States); Offerman, H.L. [Oak Ridge National Lab., TN (United States)]|[Oak Ridge Associated Universities, Inc., TN (United States)

1993-12-31

348

POSTFLEDGING SURVIVAL AND MOVEMENT IN DICKCISSELS (SPIZA AMERICANA): IMPLICATIONS FOR HABITAT MANAGEMENT AND CONSERVATION  

Microsoft Academic Search

When land managers incorporate the habitat needs of grassland birds into their planning, they typically rely on management recommendations based on habitat use by adults during nesting. Habitat requirements for other critical life stages are seldom known and may diff er from those of nesting adults. Using radio- telemetry, we examined survival and habitat use by juvenile Dickcissels (Spiza ameri-

Lorelle I. Berkeley; John P. McCarty; L. LaReesa Wolfenbarger

2007-01-01

349

Factors influencing quality of life in Chinese patients with persistent somatoform pain disorder.  

PubMed

This cross-sectional survey aimed to explore quality of life (QoL) and its correlated factors in Chinese patients with persistent somatoform pain disorder (PSPD) and their related correlation factors in Shanghai, China. A total of 60 patients were assessed with Short Form (36) health survey (SF-36) for QoL, medical outcomes study pain measurement (MOSPM) for pain symptoms, Hamilton depression scale - 17 items (HAMD) for depression and Hamilton anxiety scale (HAMA) for anxiety. Results were as follows: (1) Patients scored significantly lower on all SF-36 subscales' scores (?p?influencing PCS and MCS. PMID:24428222

Luo, Yan-Li; Heeramun-Aubeeluck, Anisha; Huang, Xiao; Ye, Gang; Wu, Heng; Sun, Lin; Liu, Liang; Wu, Wen-Yuan; Lu, Zheng; Li, Chun-Bo; Zhang, Ming-Yuan

2014-12-01

350

Influence of perflubron emulsion particle size on blood half-life and febrile response in rats.  

PubMed

Perfluorochemical (PFC) emulsions are particulate in nature and, as such, can cause delayed febrile reactions when injected intravenously. This study investigated the influence of emulsion particle size on intravascular retention and on body temperature changes in unrestrained conscious rats. Concentrated (60% to 90% w/v) emulsions based on perflubron (perfluorooctyl bromide [PFOB]) with mean particle sizes ranging from 0.05 microns to 0.63 microns were tested. Rats were fitted with a chronic jugular catheter and an abdominal body temperature telemetry unit. Fully recovered, conscious rats were monitored for 24 hours after infusion (dose = 2.7 g PFC/kg). Emulsion blood half-life (T1/2) was determined from blood perflubron levels measured by gas chromatography. Emulsions with a particle size of 0.2-0.3 microns caused fevers (6 to 8 hour duration) which peaked at 1-1.5 degrees C above normal (approximately 37.5 degrees C). Fevers could be blocked by i.v. treatment with either cyclooxygenase inhibitors (ibuprofen) or corticosteroids (dexamethasone). Both intensity and duration of the temperature response, quantified by area under the temperature curve, was decreased significantly for emulsions with a particle size < or = 0.12 micron. Blood T1/2 varied inversely with particle size, and was 3 to 4 fold longer for emulsions with a mean particle size < or = 0.2 micron. Thus, smaller emulsion particles more effectively evaded the reticuloendothelial system, which resulted in longer intravascular retention, less macrophage activity, and reduced febrile responses. PMID:7849919

Keipert, P E; Otto, S; Flaim, S F; Weers, J G; Schutt, E A; Pelura, T J; Klein, D H; Yaksh, T L

1994-01-01

351

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

352

The Influence of Abnormal Sex Differences in Life Expectancy on National Happiness  

Microsoft Academic Search

Countries with better health, as indexed by life expectancy, score higher on subjective well-being (SWB). It was predicted\\u000a that deviations from the average sex difference in life expectancy (reflecting reproductive competition among males and discrimination\\u000a against females) would be inversely related to happiness. Regression analysis of SWB for 178 countries found that deviations\\u000a from the average sex difference in life

Nigel Barber

2009-01-01

353

Socioeconomic influences at different life stages on health in Guangzhou, China  

Microsoft Academic Search

In long-term developed countries socioeconomic position across the life course is positively associated with health. We examined these associations in a developing country with a history of efforts to reorganize the social hierarchy. Taking a life course perspective, we used multi-variable logistic regression to assess the association of socioeconomic disadvantage at four life stages (measured by parental possessions, education, longest-held

Timothy M. Elwell-Sutton; Chao Qiang Jiang; Wei Sen Zhang; Kar Keung Cheng; Tai Hing Lam; Gabriel M. Leung; C. M. Schooling

2011-01-01

354

Susceptibility of eastern U.S. habitats to invasion of Celastrus orbiculatus (oriental bittersweet) following fire  

USGS Publications Warehouse

Fire effects on invasive species are an important land management issue in areas subjected to prescribed fires as well as wildfires. These effects on invasive species can be manifested across life stages. The liana Celastrus orbiculatus (oriental bittersweet) is a widespread invader of eastern US habitats including those where fire management is in practice. This study examined if prescribed fire makes these habitats more susceptible to invasion of C. orbiculatus by seed at Indiana Dunes National Lakeshore. Four treatments (control, litter removed, high and low intensity fire) were applied in six habitat types (sand savanna/woodland, sand prairie, moraine prairie, sand oak forest, beech-maple forest, and oak-hickory forest) and germinating seedlings were tracked over two growing seasons. Treatment did not have a significant effect on the germination, survival, or biomass of C. orbiculatus. However, habitat type did influence these responses mostly in the first growing season. Moraine prairie, beech-maple forest, and oak-hickory forests had the greatest peak percentage of germinants. Moraine prairie had significantly greater survival than oak forest and savanna habitats. Control plots with intact litter, and the moraine prairie habitat had the tallest seedlings at germination, while tallest final heights and greatest aboveground biomass were highest in oak forest. Thus, fire and litter removal did not increase the susceptibility of these habitats to germination and survival of C. orbiculatus. These results indicate that most eastern US habitats are vulnerable to invasion by this species via seed regardless of the level or type of disturbance to the litter layer.

Leicht-Young, Stacey A.; Pavlovic, Noel B.; Grundel, Ralph

2013-01-01

355

Maternal and early life influences on calcaneal ultrasound parameters and metacarpal morphometry in 7- to 9-year-old children  

Microsoft Academic Search

We investigated the relationship between maternal and early life influences, calcaneal ultrasound parameters, and metacarpal\\u000a morphometry in 7- to 9-year-old children (n = 109) of mixed ancestral origin from a working class community. Their mothers had participated in a nutrition and pregnancy\\u000a study at the time of the birth. Demographic and maternal data were collected. Anthropometry was assessed. Broadband ultrasound

Lisa Micklesfield; Naomi Levitt; Muhammed Dhansay; Shane Norris; Lize van der Merwe; Estelle Lambert

2006-01-01

356

The Influence of Leisure Preference, Life Priority and Making Time on Regular Participation in Leisure Time Physical Activity  

Microsoft Academic Search

Using an attitude?behaviour theory approach this study examined the direct and indirect influence of preference, life priority and time allocation on regular participation in leisure?time physical activity (LTPA). The cross?sectional study used self?report questionnaires to collect data from a random sample of 250 people aged 19 to 87 years living in an Australian city. The findings suggest that people's regular

Melinda J Craike

2007-01-01

357

The influence of high magnitude/ low frequency flood events on the spawning habitat of Atlantic salmon in the headwaters of a Scottish stream.  

NASA Astrophysics Data System (ADS)

In upland salmonid spawning streams, a large proportion of sediment supply is generated in steep headwater reaches during low frequency, high magnitude flood events. These events are integral in dictating channel morphology in these streams. Previous work on a number of Scottish upland streams has suggested that material introduced to the channel during these events is the dominant source of salmonid spawning-calibre sediment and, being important in dictating channel morphology through-out the system, key in controlling the distribution of fish habitats. In headwater reaches, salmonid spawning habitat tends to be limited by the quantity and distribution of suitable sediments, the hydraulics of such locations tending to transport gravel-sized material downstream. Data collected on the Allt a' Ghlinne Bhig (an upland tributary of the River Tay, Scotland) has shown that headwater accumulations of gravel as a result of episodic sediment input during large flood events can provide important spawning habitat, although such features are intrinsically unstable. Uptake of these habitats may be disproportionately important to juvenile production. The stream morphology and discharge associated with over 400 incidents of Atlantic salmon spawning were recorded over three consecutive seasons (2000, 2001 and 2002). Two high magnitude flood events in September 2001 and July 2002 resulted in major sediment input to the headwaters, heavily modifying the character of the channel and producing many substantial accumulations of gravel. In the season prior to these events (2000), no spawning was observed in these locations. During the subsequent surveys (2001 and 2002), a significant number of spawning incidents were observed in the headwaters, potentially providing stock to uptake habitat in these important headwater areas. Although stream discharge during the spawning period is known to affect access to headwater reaches, flows between the three study periods were not significantly different. However, subsequent morphological re-surveys revealed that these gravel accumulations tend to be transient, unstable features in headwater areas. The high transport capacity of the channel in these locations (as a result of steep slopes and high rainfall intensities) rapidly initiated the downstream movement of sediment introduced to the system during the two major flood events. Scour depths of gravel accumulations during the incubation period were sufficient to result in high levels of embryo mortality. As it propagates downstream, the pulse of sediment introduced by these two events may have important implications for channel morphology and, therefore, the distribution of salmon habitats through-out the system. Ongoing monitoring of channel morphology and spawning patterns at the Allt a' Ghlinne Bhig aims to assess this process.

Moir, H.; Gibbins, C.; Soulsby, C.; Webb, J.

2002-12-01

358

The influence of oceanographic fronts and early-life-history traits on connectivity among littoral fish species.  

PubMed

The spatial distribution of neutral genetic diversity is mainly influenced by barriers to dispersal. The nature of such barriers varies according to the dispersal means and capabilities of the organisms concerned. Although these barriers are often obvious on land, in the ocean they can be more difficult to identify. Determining the relative influence of physical and biotic factors on genetic connectivity remains a major challenge for marine ecologists. Here, we compare gene flow patterns of 7 littoral fish species from 6 families with a range of early-life-history traits sampled at the same geographic locations across common environmental discontinuities in the form of oceanic fronts in the Western Mediterranean. We show that these fronts represent major barriers to gene flow and have a strong influence on the population genetic structure of some fish species. We also found no significant relation between the early-life-history traits most commonly investigated (egg type, pelagic larval duration, and inshore-offshore spawning) and gene flow patterns, suggesting that other life-history factors should deserve attention. The fronts analyzed and the underlying physical mechanisms are not site-specific but common among the oceans, suggesting the generality of our findings. PMID:19164518

Galarza, Juan A; Carreras-Carbonell, Josep; Macpherson, Enrique; Pascual, Marta; Roques, Severine; Turner, George F; Rico, Ciro

2009-02-01

359

The influence of neurocognitive deficits and symptoms on quality of life in schizophrenia.  

PubMed Central

The purpose of the present study was to examine the relationship between neurocognitive deficits and self-reported quality of life in order to examine whether neurocognitive impairment interferes with any aspects of quality of life for patients with schizophrenia. Forty-two outpatients with stable chronic schizophrenia were assessed for neurocognitive deficits using a computerized test battery, and all patients completed a version of the Sickness Impact Profile (SIP) to assess their quality of life across a variety of domains. The neurocognitive assessment tests revealed significant deficits compared with normal control subjects, particularly with respect to impaired iconic memory and frontal functioning. Patients reported that their quality of life was compromised. Despite the substantiation of marked neurocognitive deficits and reduced quality of life, correlations between neurocognitive deficits and quality of life were largely nonsignificant or very weak. Symptom expression, however, particularly with regard to general psychopathology on the Positive and Negative Syndrome Scale (PANSS), was significantly associated with quality of life. These results suggest that neurocognitive deficits in schizophrenia, while often profound, appear to have little direct impact on the patient's perceived quality of life. PMID:9262045

Heslegrave, R J; Awad, A G; Voruganti, L N

1997-01-01

360

Influence of herbivores on a perennial plant: variation with life history stage and herbivore species  

Microsoft Academic Search

Herbivores have diverse impacts on their host plants, potentially altering survival, growth, fecundity, and other aspects of plant performance. Especially for longer-lived plant species, the effects of a single herbivore species can vary markedly throughout the life of the host plant. In addition, the effects of herbivory during any given life history stage of a host plant may also vary

Peter J. Warner; Hall J. Cushman

2002-01-01

361

Physical Activity and Quality of Life: Assessing the Influence of Activity Frequency, Intensity, Volume, and Motives  

Microsoft Academic Search

In the present study, the authors investigated the impact of exercise frequency, intensity, and volume along with exercise motives on quality of life (QOL) reports. The authors assessed exercise habits with the Godin Leisure Time Activity Scale and measured exercise motives with the Reasons for Exercise Inventory. The Quality of Life Inventory assessed satisfaction in 16 domains including health, work,

M. Kathleen B. Lustyk; Laura Widman; Amy A. E. Paschane; Karen C. Olson

2004-01-01

362

The influence of raw material characteristics on the storage life of fresh-cut butterhead lettuce  

Microsoft Academic Search

The physiological characteristics of 5 butterhead lettuce cultivars (Lactuca sativa L.) were investigated using etiolated leaves. Their storage life under modified and controlled atmospheres was assessed. When prepacked butterhead lettuce was maintained under a low oxygen atmosphere to prevent enzymatic browning, high CO2 content was the main factor increasing the rate of decay. Shelf life was negatively correlated with respiration

Patrick Varoquaux; Jérôme Mazollier; Guy Albagnac

1996-01-01

363

The influence of life history milestones and association networks on crop-raiding behavior in male African elephants.  

PubMed

Factors that influence learning and the spread of behavior in wild animal populations are important for understanding species responses to changing environments and for species conservation. In populations of wildlife species that come into conflict with humans by raiding cultivated crops, simple models of exposure of individual animals to crops do not entirely explain the prevalence of crop raiding behavior. We investigated the influence of life history milestones using age and association patterns on the probability of being a crop raider among wild free ranging male African elephants; we focused on males because female elephants are not known to raid crops in our study population. We examined several features of an elephant association network; network density, community structure and association based on age similarity since they are known to influence the spread of behaviors in a population. We found that older males were more likely to be raiders than younger males, that males were more likely to be raiders when their closest associates were also raiders, and that males were more likely to be raiders when their second closest associates were raiders older than them. The male association network had sparse associations, a tendency for individuals similar in age and raiding status to associate, and a strong community structure. However, raiders were randomly distributed between communities. These features of the elephant association network may limit the spread of raiding behavior and likely determine the prevalence of raiding behavior in elephant populations. Our results suggest that social learning has a major influence on the acquisition of raiding behavior in younger males whereas life history factors are important drivers of raiding behavior in older males. Further, both life-history and network patterns may influence the acquisition and spread of complex behaviors in animal populations and provide insight on managing human-wildlife conflict. PMID:22347468

Chiyo, Patrick I; Moss, Cynthia J; Alberts, Susan C

2012-01-01

364

The influence of habitat availability and landscape structure on the distribution of wood cricket ( Nemobius sylvestris ) on the Isle of Wight, UK  

Microsoft Academic Search

Little information is available regarding the landscape ecology of woodland invertebrate species with limited dispersal ability.\\u000a An investigation was therefore conducted within woodland fragments in an agricultural landscape for the flightless wood cricket\\u000a (Nemobius sylvestris) on the Isle of Wight, UK. The current pattern of distribution of the species, established during a field survey, was related\\u000a to measures of habitat

Niels C. Brouwers; Adrian C. Newton

2009-01-01

365

The influence of floodplain habitat on the quantity and quality of riverine phytoplankton carbon produced during the flood season in San Francisco Estuary  

Microsoft Academic Search

Primary productivity, community respiration, chlorophyll a concentration, phytoplankton species composition, and environmental factors were compared in the Yolo Bypass floodplain and\\u000a adjacent Sacramento River in order to determine if passage of Sacramento River through floodplain habitat enhanced the quantity\\u000a and quality of phytoplankton carbon available to the aquatic food web and how primary productivity and phytoplankton species\\u000a composition in these

Peggy W. Lehman; Ted Sommer; Linda Rivard

2008-01-01

366

Does human-induced habitat modification influence the impact of introduced species? A case study on cavity-nesting by the introduced common myna (Acridotheres tristis) and two Australian native parrots.  

PubMed

Introduced species pose a major threat to biodiversity across the globe. Understanding the impact of introduced species is critical for effective management. Many species around the world are reliant on tree cavities, and competition for these resources can be intense: threatening the survival of native species. Through the establishment of 225 nest boxes, we examined the relationship between tree density and the abundance and nesting success of three bird species in Canberra, Australia. The common myna (Acridotheres tristis) is an introduced species in Australia, and the crimson rosella (Platycercus elegans) and eastern rosella (Platycercus eximius) are native species. We then investigated the impact of common myna nest box occupation on crimson rosella and eastern rosella abundance. Tree density significantly influenced the abundance and cavity-nesting of all three species. Common myna abundance (birds per square kilometer) was greatest at low tree density sites (101.9 ± 22.4) and declined at medium (45.4 ± 10.1) and high (9.7 ± 3.6) tree density sites. The opposite pattern was observed for the crimson rosella, with greater abundance (birds per square kilometer) at high tree density sites (83.9 ± 9.3), declining over medium (61.6 ± 6.4) and low (31.4 ± 3.9) tree density sites. The eastern rosella was more abundant at medium tree density sites (48.6 ± 8.0 birds per square kilometer). Despite the strong influence of tree density, we found a significant negative relationship between common myna nest box occupancy and the abundance of the crimson rosella (F 1,13 = 7.548, P = 0.017) and eastern rosella (F 1,13 = 9.672, P < 0.001) at some sites. We also observed a slight increase in rosella nesting interruptions by the common myna at lower tree densities (high: 1.3% ± 1.3, medium: 6.6% ± 2.2, low: 12.7% ± 6.2), although this increase was not statistically significant (F 2,40 = 2.435, P = 0.100). Our study provides the strongest evidence to date for the negative impact of the common myna on native bird abundance through cavity-nesting competition. However, due to the strong influence of habitat on species abundance and nesting, it is essential to investigate the impacts of introduced species in conjunction with habitat variation. We also suggest one component of introduced species management could include habitat restoration to reduce habitat suitability for introduced species. PMID:23716011

Grarock, Kate; Lindenmayer, David B; Wood, Jeffrey T; Tidemann, Christopher R

2013-10-01

367

Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary, Annual Report of Research.  

SciTech Connect

In 2002 with support from the U.S. Army Corps of Engineers (USACE), an interagency research team began investigating salmon life histories and habitat use in the lower Columbia River estuary to fill significant data gaps about the estuary's potential role in salmon decline and recovery . The Bonneville Power Administration (BPA) provided additional funding in 2004 to reconstruct historical changes in estuarine habitat opportunities and food web linkages of Columbia River salmon (Onchorhynchus spp.). Together these studies constitute the estuary's first comprehensive investigation of shallow-water habitats, including selected emergent, forested, and scrub-shrub wetlands. Among other findings, this research documented the importance of wetlands as nursery areas for juvenile salmon; quantified historical changes in the amounts and distributions of diverse habitat types in the lower estuary; documented estuarine residence times, ranging from weeks to months for many juvenile Chinook salmon (O. tshawytscha); and provided new evidence that contemporary salmonid food webs are supported disproportionately by wetland-derived prey resources. The results of these lower-estuary investigations also raised many new questions about habitat functions, historical habitat distributions, and salmon life histories in other areas of the Columbia River estuary that have not been adequately investigated. For example, quantitative estimates of historical habitat changes are available only for the lower 75 km of the estuary, although tidal influence extends 217 km upriver to Bonneville Dam. Because the otolith techniques used to reconstruct salmon life histories rely on detection of a chemical signature (strontium) for salt water, the estuarine residency information we have collected to date applies only to the lower 30 or 35 km of the estuary, where fish first encounter ocean water. We lack information about salmon habitat use, life histories, and growth within the long tidal-fresh reaches of the main-stem river and many tidally-influenced estuary tributaries. Finally, our surveys to date characterize wetland habitats within island complexes distributed in the main channel of the lower estuary. Yet some of the most significant wetland losses have occurred along the estuary's periphery, including shoreline areas and tributary junctions. These habitats may or may not function similarly as the island complexes that we have surveyed to date. In 2007 we initiated a second phase of the BPA estuary study (Phase II) to address specific uncertainties about salmon in tidal-fresh and tributary habitats of the Columbia River estuary. This report summarizes 2007 and 2008 Phase II results and addresses three principal research questions: (1) What was the historic distribution of estuarine and floodplain habitats from Astoria to Bonneville Dam? (2) Do individual patterns of estuarine residency and growth of juvenile Chinook salmon vary among wetland habitat types along the estuarine tidal gradient? (3) Are salmon rearing opportunities and life histories in the restoring wetland landscape of lower Grays River similar to those documented for island complexes of the main-stem estuary? Phase II extended our analysis of historical habitat distribution in the estuary above Rkm 75 to near Bonneville Dam. For this analysis we digitized the original nineteenth-century topographic (T-sheets) and hydrographic (H-sheets) survey maps for the entire estuary. Although all T-sheets (Rkm 0 to Rkm 206) were converted to GIS in 2005 with support for the USACE estuary project, final reconstruction of historical habitats throughout the estuary requires completion of the remaining H-sheet GIS maps above Rkm 75 and their integration with the T-sheets. This report summarizes progress to date on compiling the upper estuary H-sheets above Rkm 75. For the USACE estuary project, we analyzed otoliths from Chinook salmon collected near the estuary mouth in 2003-05 to estimate variability in estuary residence times among juvenile out migrants. In Phase II we expanded these analyses to comp

Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance [Northwest Fisheries Science Center

2009-05-15

368

Distributions and habitat associations of the bridled monocle bream Scolopsis bilineatus (Nemipteridae): a demographic approach.  

PubMed

This study focussed on the demography and ecology of Scolopsis bilineatus at three locations on the Great Barrier Reef: the Lizard Island Group, Orpheus Island and One Tree Island. Scolopsis bilineatus lived for up to 16?years and had four distinct life-history stages, which varied in their distribution patterns, habitat use and reproductive behaviour. Pre-maturational sex change occurred whereby all males were derived from immature females, and males grew faster and larger than females. Small females and larger males generally formed pairs, which influenced their spatial distributions at small scales. Distributions of S. bilineatus were influenced by depth and exposure within reefs, particularly for juveniles, and most fish were found in shallow, sheltered habitats. Abundance was influenced by benthic cover, and was higher in areas of high coral cover and low where algae were abundant. Habitat associations were stronger at the microhabitat scale, and shelter sites were important for adults. Ontogenetic changes in microhabitat associations were found: juveniles occupied sand and rubble, and adults occupied shelters such as caves and overhangs. Adults showed site fidelity for shelter sites over a period of 4?days and returned to specific shelter sites repeatedly. These findings illustrate the importance of understanding the spatial ecology and habitat use of coral reef fishes, particularly with reference to size-based changes within species. PMID:23991878

Boaden, A E; Kingsford, M J

2013-09-01

369

Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle  

PubMed Central

Background The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes. Methods For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation. Results Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated by a decrease in the ADD1/SREBP-1c signal. Importantly, our results demonstrated that a combination of lotus leaf extract solution and L-carnitine reduced triglyceride accumulation to a greater extent compared to incubation with either substance alone. Conclusions Overall, our data demonstrate that a combination of lotus leaf extract and L-carnitine reduced triglyceride accumulation in human (pre)adipocytes by affecting different processes during the adipocyte life cycle. For this reason, this combination might represent a treatment option for obesity-related diseases. PMID:20687953

2010-01-01

370

Influence of life history strategies on sensitivity, population growth and response to climate for sympatric alpine birds  

PubMed Central

Background The life history strategy of a species can influence how populations of that species respond to environmental variation. In this study, we used a matrix modeling approach to examine how life history differences among sympatric rock and white-tailed ptarmigan affect the influence of demographic rates on population growth (?) and the potential response to a changing climate. Rock ptarmigan have a slower life history strategy than white-tailed ptarmigan in the study region with lower annual reproductive effort but higher adult survival. Results Based on data from a 5-year field study, deterministic estimates of ? indicated that populations were stable for rock ptarmigan (??=?1.01), but declining for white-tailed ptarmigan (??=?0.96). The demographic rates with the highest elasticity for rock ptarmigan were the survival of after-second year females, followed by juvenile survival and success of the first nest. For white-tailed ptarmigan, juvenile survival had the highest elasticity followed by success of the first nest and survival of second-year females. Incorporating stochasticity into the demographic rates led to a 2 and 4% drop in ? for rock and white-tailed ptarmigan respectively. Using data from the first three years we also found that population growth rates of both species were depressed following an increased frequency of severe years, but less so for rock ptarmigan which showed greater resilience under these conditions. Conclusions Our results provide evidence that populations of closely related species can vary in their response to environmental change as a consequence of life history differences. Rock ptarmigan, with a slower life history, are more responsive to demographic rates that influence survival and older life stages but this response is tempered by the extent of variability in each of the rates. Thus, predictions need to consider both aspects in modeling population response to a varying climate. Juvenile survival was a highly influential rate for both species, but the period from independence to first breeding is a poorly understood stage for many bird species. Additional study on juvenile survival, the influence of density dependence and the effects of predators as the mechanism driving survival-reproduction tradeoffs are all areas requiring further study. PMID:22747571

2012-01-01

371

The Influence of Major Life Events on Economic Attitudes in a World of Gene-Environment Interplay  

PubMed Central

The role of “genes” on political attitudes has gained attention across disciplines. However, person-specific experiences have yet to be incorporated into models that consider genetic influences. Relying on a gene-environment interplay approach, this study explicates how life-events, such as losing one’s job or suffering a financial loss, influence economic policy attitudes. The results indicate genetic and environmental variance on support for unions, immigration, capitalism, socialism and property tax is moderated by financial risks. Changes in the magnitude of genetic influences, however, are temporary. After two years, the phenotypic effects of the life events remain on most attitudes, but changes in the sources of individual differences do not. Univariate twin models that estimate the independent contributions of genes and environment on the variation of attitudes appear to provide robust baseline indicators of sources of individual differences. These estimates, however, are not event or day specific. In this way, genetic influences add stability, while environment cues change, and this process is continually updated. PMID:24860199

Hatemi, Peter K.

2014-01-01

372

The effects of chemical interactions and culture history on the colonization of structured habitats by competing bacterial populations  

PubMed Central

Background Bacterial habitats, such as soil and the gut, are structured at the micrometer scale. Important aspects of microbial life in such spatial ecosystems are migration and colonization. Here we explore the colonization of a structured ecosystem by two neutrally labeled strains of Escherichia coli. Using time-lapse microscopy we studied the colonization of one-dimensional arrays of habitat patches linked by connectors, which were invaded by the two E. coli strains from opposite sides. Results The two strains colonize a habitat from opposite sides by a series of traveling waves followed by an expansion front. When population waves collide, they branch into a continuing traveling wave, a reflected wave and a stationary population. When the two strains invade the landscape from opposite sides, they remain segregated in space and often one population will displace the other from most of the habitat. However, when the strains are co-cultured before entering the habitats, they colonize the habitat together and do not separate spatially. Using physically separated, but diffusionally coupled, habitats we show that colonization waves and expansion fronts interact trough diffusible molecules, and not by direct competition for space. Furthermore, we found that colonization outcome is influenced by a culture’s history, as the culture with the longest doubling time in bulk conditions tends to take over the largest fraction of the habitat. Finally, we observed that population distributions in parallel habitats located on the same device and inoculated with cells from the same overnight culture are significantly more similar to each other than to patterns in identical habitats located on different devices inoculated with cells from different overnight cultures, even tough all cultures were started from the same ?80°C frozen stock. Conclusions We found that the colonization of spatially structure habitats by two interacting populations can lead to the formation of complex, but reproducible, spatiotemporal patterns. Furthermore, we showed that chemical interactions between two populations cause them to remain spatially segregated while they compete for habitat space. Finally, we observed that growth properties in bulk conditions correlate with the outcome of habitat colonization. Together, our data show the crucial roles of chemical interactions between populations and a culture’s history in determining the outcome of habitat colonization. PMID:24884963

2014-01-01

373

Mineral interface in extreme habitats: a niche for primitive molecular evolution for the appearance of different forms of life on earth.  

PubMed

Innumerable primitive membrane and protocell models in latter stages of chemical evolution are based on the properties of minerals' interfaces with primitive seawater. The ordering mechanism induced by mineral interfaces has been the basis of several prebiotic models of molecular complexification and compartmentalization towards the appearance and evolution of different forms of life. Since mineral-aqueous media interfaces have been considered as initial stages of prebiotic models dealing with the formation of energy-transducing systems, the interface formed by pyrite in the presence of artificial primitive seawater was chosen to show the functional richness of this special niche. Interfaces--especially sulphide interfaces--were proposed as suitable niches for a two-carbon extant metabolism, synthesis and polymerization of nucleotides--to form ancient RNA strands--and assembly of amino acids synthesized in its vicinity. Accumulation of precursors at sulphide interfaces could have avoided their dilution into the Hadean seas and provided a suitable geochemical environment for a variety of molecular interactions. In this essay, we present a short review of the proposed roles of mineral interfaces in chemical evolution towards the appearance of primitive membranes, which might have been relevant for the advent of cellular life before its divergent evolution and differentiation. This survey covers several previous studies on the early cycles of energy conservation and of the formation of molecules carrying genetic information. PMID:17317327

de Souza-Barros, Fernando; Vieyra, Adalberto

2007-01-01

374

Reciprocal Influences between Negative Life Events and Callous-Unemotional Traits.  

PubMed

Children with conduct problems and co-occurring callous-unemotional (CU) traits show more severe, stable, and aggressive antisocial behaviors than those without CU traits. Exposure to negative life events has been identified as an important contributing factor to the expression of CU traits across time, although the directionality of this effect has remained unknown due to a lack of longitudinal study. The present longitudinal study examined potential bidirectional effects of CU traits leading to experiencing more negative life events and negative life events leading to increases in CU traits across 3 years among a sample of community-based school-aged (M?=?10.9, SD?=?1.71 years) boys and girls (N?=?98). Repeated rating measures of CU traits, negative life events and conduct problems completed by children and parents during annual assessments were moderately to highly stable across time. Cross-lagged models supported a reciprocal relationship of moderate magnitude between child-reported CU traits and "controllable" negative life events. Parent-reported CU traits predicted "uncontrollable" life events at the earlier time point and controllable life events at the later time point, but no reciprocal effect was evident. These findings have important implications for understanding developmental processes that contribute to the stability of CU traits in youth. PMID:24875593

Kimonis, Eva R; Centifanti, Luna C M; Allen, Jennifer L; Frick, Paul J

2014-11-01

375

Can settlement in natal-like habitat explain maladaptive habitat selection?  

PubMed Central

The study of habitat selection has long been influenced by the ideal free model, which maintains that young adults settle in habitat according to its inherent quality and the density of conspecifics within it. The model has gained support in recent years from the finding that conspecifics produce cues inadvertently that help prebreeders locate good habitat. Yet abundant evidence shows that animals often fail to occupy habitats that ecologists have identified as those of highest quality, leading to the conclusion that young animals settle on breeding spaces by means not widely understood. Here, we report that a phenomenon virtually unknown in nature, natal habitat preference induction (NHPI), is a strong predictor of territory settlement in both male and female common loons (Gavia immer). NHPI causes young animals to settle on natal-like breeding spaces, but not necessarily those that maximize reproductive success. If widespread, NHPI might explain apparently maladaptive habitat settlement. PMID:23804619

Piper, Walter H.; Palmer, Michael W.; Banfield, Nathan; Meyer, Michael W.

2013-01-01

376

Can settlement in natal-like habitat explain maladaptive habitat selection?  

PubMed

The study of habitat selection has long been influenced by the ideal free model, which maintains that young adults settle in habitat according to its inherent quality and the density of conspecifics within it. The model has gained support in recent years from the finding that conspecifics produce cues inadvertently that help prebreeders locate good habitat. Yet abundant evidence shows that animals often fail to occupy habitats that ecologists have identified as those of highest quality, leading to the conclusion that young animals settle on breeding spaces by means not widely understood. Here, we report that a phenomenon virtually unknown in nature, natal habitat preference induction (NHPI), is a strong predictor of territory settlement in both male and female common loons (Gavia immer). NHPI causes young animals to settle on natal-like breeding spaces, but not necessarily those that maximize reproductive success. If widespread, NHPI might explain apparently maladaptive habitat settlement. PMID:23804619

Piper, Walter H; Palmer, Michael W; Banfield, Nathan; Meyer, Michael W

2013-08-22

377

Temporal transferability of wildlife habitat models: implications for habitat  

E-print Network

modelling constitutes a suitable tool for characterizing wildlife habitat and monitoring its temporal transferability, MODIS, remote sensing, species distribution model, WDRVI, wildlife habitat monitoring, WolongORIGINAL ARTICLE Temporal transferability of wildlife habitat models: implications for habitat

378

The effects of understory bamboo on broad-scale estimates of giant panda habitat  

Microsoft Academic Search

Understory vegetation is an important habitat component for many wildlife species. Previous broad-scale studies on biodiversity and wildlife habitat have suffered from a lack of detailed information about understory distribution. Consequently, it is unclear how understory distribution influences the analysis of habitat quantity and spatial distribution. To address this problem, we compared estimates of giant panda (Ailuropoda melanoleuca) habitat with

Marc Linderman; Scott Bearer; Li An; Yingchun Tan; Zhiyun Ouyang; Jianguo Liu

2005-01-01

379

Maternal influence on feeding site avoidance behaviour of lambs  

Microsoft Academic Search

Ewes can play a critical role in moulding habitat preferences of their daughters. Little is known, however, about how feeding site preferences of lambs can be modified by manipulating the behaviour of their dams. We conducted an experiment with sheep to investigate the influence of shock-trained mothers and early-life aversive experiences on the feeding site choices of lambs. Twelve ewes

Christina M. Black-Rubio; Andrés F. Cibils; William R. Gould

2007-01-01

380

Temperature influence on life table statistics of the chicken mite Dermanyssus gallinae (Acari: Dermanyssidae).  

PubMed

An age-specific life table for the chicken mite Dermanyssus gallinae (DeGeer, 1778) was based on various observations carried out at 25 degrees C. The generation time was calculated to be 16.8 days; the intrinsic rate of natural increase was 0.12 per day, and the net reproductive rate was 7.2. A nonlinear function was found satisfactory to describe the developmental rate of the different immature life-stages at temperatures below 40 degrees C. The stage-specific survival of the immature life-stages was generally high between 10 and 37 degrees C, but decreased quickly outside this temperature range. Most of the eggs were laid during the first three weeks of the adult life. The proportion of surviving females rapidly decreases after moulting to the adult stage. At a temperature of 30 degrees C, the highest number of eggs (3 eggs per day) was laid. PMID:1511637

Maurer, V; Baumgärtner, J

1992-07-01

381

Early childhood factors influencing health-related quality of life in adolescents at 13 years  

Microsoft Academic Search

Objective: To understand the relationship of health-related quality of life (HR-QOL) to early life experience. Methodology: Eight thousand five hundred and fifty-six women enrolled in a prospective study at their first antenatal clinic visit. At 13 years, of 5345 women remaining, a consecutive sample of 901 mother\\/child pairs provided data on adolescent HR-QOL using the Child Health Questionnaire-Parent Report form

AJ Wilkins; MJ O'Callaghan; JM Najman; W Bor; GM Williams; G Shuttlewood

2004-01-01

382

Socioeconomic influences at different life stages on health in Guangzhou, China.  

PubMed

In long-term developed countries socioeconomic position across the life course is positively associated with health. We examined these associations in a developing country with a history of efforts to reorganize the social hierarchy. Taking a life course perspective, we used multi-variable logistic regression to assess the association of socioeconomic disadvantage at four life stages (measured by parental possessions, education, longest-held occupation and current household income) with self-rated health, chronic obstructive pulmonary disease (COPD) and metabolic syndrome in 20,086 Chinese adults aged ?50 years from the Guangzhou Biobank Cohort Study (2005-2008). Model comparisons were used to determine whether the number of exposures to disadvantage (accumulation of risk) was more important than the life stage of exposure (critical periods). Socioeconomic disadvantage across the life course was associated with poor self-rated health, COPD and, in women only, with metabolic syndrome. Adjusting for adult health-related behavior (smoking, alcohol use and physical exercise) altered these associations very little. Associations between socioeconomic disadvantage and health in this Southern Chinese population were broadly similar to those found in Western countries in terms of the accumulation of disadvantage across the life course. However, longest-held occupation was not independently associated with adult health and socioeconomic disadvantage was not associated with metabolic syndrome in men. This suggests that the mechanisms linking socioeconomic position to health in China may be different from those in Western populations and may require context-specific policy interventions. PMID:21550152

Elwell-Sutton, Timothy M; Jiang, Chao Qiang; Zhang, Wei Sen; Cheng, Kar Keung; Lam, Tai Hing; Leung, Gabriel M; Schooling, C M

2011-06-01

383

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.

384

HABITAT ASSESSMENT METHODS  

EPA Science Inventory

This chapter summarizes and evaluated the habitat assessment protocols of five agencies, USEPA/EMAP/SW, USGS/NAWQA, USEPA/RBP, Ohio EPA, and MDNR/MBSS. It begins with a description of the origin of the habitat indices most widely used by these agencies. Then the habitat assessmen...

385

Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally induced temperature influences on embryo development rate.  

PubMed

Intrinsic processes are assumed to underlie life history expression and trade-offs, but extrinsic inputs are theorised to shift trait expression and mask trade-offs within species. Here, we explore application of this theory across species. We do this based on parentally induced embryo temperature as an extrinsic input, and mass-specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected interspecific trade-off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade-offs across species. PMID:23473270

Martin, Thomas E; Ton, Riccardo; Niklison, Alina

2013-06-01

386

Density Management and Biodiversity Stand Density Influences  

E-print Network

Density Management and Biodiversity Joan Hagar USGS-FRESC #12;Stand Density Influences Wildlife Density Influences Wildlife Habitat · Tree architecture · Vegetative diversity · Structural Complexity #12;Vertical AND Functional Diversity! #12;Stand Density Influences Wildlife Habitat · Tree

387

Stressors and antistressors: how do they influence life span in HER2\\/neu transgenic mice?  

Microsoft Academic Search

The purpose of this study is to investigate possible influences of different stressors (saline injections, light deprivation and constant light regimen) and geroprotectors (Epitalon and melatonin) on survivals of female HER-2\\/neu transgenic mice. We propose a semi-parametric model of heterogeneous mortality (frailty model) for the analysis of the experimental data. In this model, we assume that treatment influences parameters of

Ganna V. Semenchenko; Vladimir N. Anisimov; Anatoli I. Yashin

2004-01-01

388

Geomorphological, trophic and human influences on the bamboo coral Isidella elongata assemblages in the deep Mediterranean: To what extent does Isidella form habitat for fish and invertebrates?  

NASA Astrophysics Data System (ADS)

We analyzed what are the best ecological conditions for megafauna associated with the bamboo coral Isidella elongata based on the geomorphological, physical and trophic information taken in 3 stations (St1, St2, St3) off the southern Catalonian coasts at 620 m depth in June 2011. Results were compared with assemblage compositions recorded in past cruises (May 1992, 1994) at the same 3 stations. St1 was in a fishing ground exploited since the 1940s over a relatively wide slope at ca. 22 km from the nearest canyon head; St2 and St3 were on a narrower slope closer to canyon heads and to the Ebro river mouth than St1. I. elongata had formed (to May 1994, at least) a dense coral forest at St2-St3 (to ca. 255 colonies/ha at St3), and some isolated colonies (to ca. 0.9 colonies/ha) were still collected in 2011. Fish and invertebrate communities significantly differed between St1 and St2/St3, with two macrourid fishes (Trachrhynchus trachyrhynchus and Nezumia aequalis) and two decapods (Plesionika martia and Plesionika acanthonotus) more abundant at St2/St3. The following ecological indicators imply better food conditions for megafauna at St2-St3 and for I. elongata itself: (i) greater density of zooplankton (copepods, euphausiids, and others) as potential prey for planktivores (including I. elongata); (ii) greater biomass and mean weight of epifaunal and infaunal deposit feeders; (iii) higher feeding intensity, F, at St3 for benthos feeders (Phycis blennoides, N. aequalis and Aristeus antennatus). Also, at St2-St3 we found higher near-bottom turbidity (indicating particle resuspension: food for suspension feeders) and finer and more reduced (Eh) sediments. The results let us suggest that corals and accompanying fauna preferently found optimal ecological conditions in the same habitat, while habitat-forming capacity by I. elongata seemed weak to generate these conditions. Coral forests may enhance detritus accumulations around them, improving habitat conditions for benthos feeders (e.g. macrourid fish). At St3 our side-scan sonar recorded three types of tracks produced by trawler doors, which match with three identified vessels occasionally operating in the area. After this low fishing activity off the Ebro Delta since the mid-1990s, almost all colonies of I. elongata has been removed. However, this impact has hardly altered fish and invertebrate composition without any significant loss of diversity, pointing also toward a rather low capacity of I. elongata facies in forming habitat for megafauna on muddy bottoms of the Mediterranean slope.

Cartes, J. E.; LoIacono, C.; Mamouridis, V.; López-Pérez, C.; Rodríguez, P.

2013-06-01

389

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. PMID:23272215

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

2012-01-01

390

End-of-Life Treatment Preferences Among Older Adults: An Assessment of Psychosocial Influences1  

PubMed Central

We explore the content and correlates of older adults’ end-of-life treatment preferences in two hypothetical terminal illness scenarios: severe physical pain with no cognitive impairment, and severe cognitive impairment with no physical pain. For each scenario, we assess whether participants would reject life-prolonging treatment, accept treatment, or do not know their preferences. Using data from the 2004 wave of the Wisconsin Longitudinal Study (N = 5,106), we estimate multinomial logistic regression models to evaluate whether treatment preferences are associated with direct experience with end-of-life issues, personal beliefs, health, and sociodemographic characteristics. Persons who have made formal end-of-life preparations, persons with no religious affiliation, mainline Protestants, and persons who are pessimistic about their own life expectancy are more likely to reject treatment in both scenarios. Women and persons who witnessed the painful death of a loved one are more likely to reject treatment in the cognitive impairment scenario only. Consistent with rational choice perspectives, our results suggest that individuals prefer treatments that they perceive to have highly probable desirable consequences for both self and family. PMID:21057589

Carr, Deborah; Moorman, Sara M.

2010-01-01

391

Ecological and life-history factors influencing the evolution of maternal antibody allocation: a phylogenetic comparison  

PubMed Central

Maternally derived yolk antibodies provide neonates with immune protection in early life at negligible cost to mothers. However, developmental effects on the neonate's future immunity are potentially costly and thus could limit yolk antibody deposition. The benefits to neonatal immunity must be balanced against costs, which may depend on neonate vulnerability to pathogens, developmental trajectories and the immunological strategies best suited to a species' pace of life. We measured yolk antibodies and life-history features of 23 species of small Neotropical birds and assessed the evidence for each of several hypotheses for life history and ecological effects on the evolution of yolk antibody levels. Developmental period and yolk antibodies are negatively related, which possibly reflect the importance of humoral immune priming through antigen exposure, and selection to avoid autoimmunity, in species with a slower pace of life. There is also a strong relationship between body size and yolk antibody concentration, suggesting that larger species are architecturally equipped to produce and transfer higher concentrations of antibodies. These results suggest that developmental effects of maternally derived antibodies, such as imprinting effects on B-cell diversity or autoimmune effects, are important and deserve more consideration in future research. PMID:19710063

Addison, BriAnne; Klasing, Kirk C.; Robinson, W. Douglas; Austin, Suzanne H.; Ricklefs, Robert E.

2009-01-01

392