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排序方式: 共有256条查询结果,搜索用时 276 毫秒
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Tina L. Cheng Jonathan D. Reichard Jeremy T. H. Coleman Theodore J. Weller Wayne E. Thogmartin Brian E. Reichert Alyssa B. Bennett Hugh G. Broders Joshua Campbell Katherine Etchison Daniel J. Feller Richard Geboy Traci Hemberger Carl Herzog Alan C. Hicks Sandra Houghton Jessica Humber Joseph A. Kath R. Andrew King Susan C. Loeb Ariane Massé Katrina M. Morris Holly Niederriter Gerda Nordquist Roger W. Perry Richard J. Reynolds D. Blake Sasse Michael R. Scafini Richard C. Stark Craig W. Stihler Steven C. Thomas Gregory G. Turner Shevenell Webb Bradford J. Westrich Winifred F. Frick 《Conservation biology》2021,35(5):1586-1597
Assessing the scope and severity of threats is necessary for evaluating impacts on populations to inform conservation planning. Quantitative threat assessment often requires monitoring programs that provide reliable data over relevant spatial and temporal scales, yet such programs can be difficult to justify until there is an apparent stressor. Leveraging efforts of wildlife management agencies to record winter counts of hibernating bats, we collated data for 5 species from over 200 sites across 27 U.S. states and 2 Canadian provinces from 1995 to 2018 to determine the impact of white-nose syndrome (WNS), a deadly disease of hibernating bats. We estimated declines of winter counts of bat colonies at sites where the invasive fungus that causes WNS (Pseudogymnoascus destructans) had been detected to assess the threat impact of WNS. Three species undergoing species status assessment by the U.S. Fish and Wildlife Service (Myotis septentrionalis, Myotis lucifugus, and Perimyotis subflavus) declined by more than 90%, which warrants classifying the severity of the WNS threat as extreme based on criteria used by NatureServe. The scope of the WNS threat as defined by NatureServe criteria was large (36% of Myotis lucifugus range) to pervasive (79% of Myotis septentrionalis range) for these species. Declines for 2 other species (Myotis sodalis and Eptesicus fuscus) were less severe but still qualified as moderate to serious based on NatureServe criteria. Data-sharing across jurisdictions provided a comprehensive evaluation of scope and severity of the threat of WNS and indicated regional differences that can inform response efforts at international, national, and state or provincial jurisdictions. We assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs, such as the North American Bat Monitoring Program (NABat), for data-driven conservation assessments and planning. 相似文献
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Holly L. Hennin Nicole K. S. Barker David W. Bradley Daniel J. Mennill 《Behavioral ecology and sociobiology》2009,64(2):151-159
To attract a breeding partner, males may behave differently when they are bachelors compared to when they are paired. Comparisons
between groups of paired males versus groups of unpaired males in temperate-breeding animals have revealed such differences
in signalling behaviour. Few studies, however, have explored how individual males alter their signalling behaviour with changes
in pairing status, and very few investigations have explored paired versus unpaired male behaviour in tropical animals. During
a 5-year study in Costa Rica, we analysed changes in the singing behaviour of male rufous-and-white wrens (Thryothorus rufalbus) when they were paired and when they were bachelors. We compared three aspects of male vocal behaviour: gross differences
in song output, variation in repertoire use and differences in song structure. Males as bachelors had significantly higher
song output and switched song types less frequently. Contrary to our expectation, bachelors sang significantly fewer song
types from their repertoire compared to when those same males had a breeding partner. Songs sung by bachelor males were higher
in syllabic diversity and had broader-bandwidth terminal syllables than the songs those males sang only when paired. Within
song types, the fine structure of songs remained consistent across pairing status. Our results demonstrate that males change
their singing behaviour with pairing status, delivering songs at a higher rate but with less variety when they are bachelors.
Rufous-and-white wrens are renowned for their vocal duets, and we discuss the pattern of repertoire use in light of their
duetting behaviour. These results enhance our understanding of how male behaviour varies with pairing status and the importance
of vocal signalling behaviour in socially monogamous tropical animals. 相似文献
246.
Phenotypic plasticity of native vs. invasive purple loosestrife: a two-state multivariate approach 总被引:4,自引:0,他引:4
The differences in phenotypic plasticity between invasive (North American) and native (German) provenances of the invasive plant Lythrum salicaria (purple loosestrife) were examined using a multivariate reaction norm approach testing two important attributes of reaction norms described by multivariate vectors of phenotypic change: the magnitude and direction of mean trait differences between environments. Data were collected for six life history traits from native and invasive plants using a split-plot design with experimentally manipulated water and nutrient levels. We found significant differences between native and invasive plants in multivariate phenotypic plasticity for comparisons between low and high water treatments within low nutrient levels, between low and high nutrient levels within high water treatments, and for comparisons that included both a water and nutrient level change. The significant genotype x environment (G x E) effects support the argument that invasiveness of purple loosestrife is closely associated with the interaction of high levels of soil nutrient and flooding water regime. Our results indicate that native and invasive plants take different strategies for growth and reproduction; native plants flowered earlier and allocated more to flower production, while invasive plants exhibited an extended period of vegetative growth before flowering to increase height and allocation to clonal reproduction, which may contribute to increased fitness and invasiveness in subsequent years. 相似文献
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Environmental Economics at the World Bank 总被引:2,自引:0,他引:2
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Formation of non-extractable pesticide residues: observations on compound differences, measurement and regulatory issues 总被引:2,自引:0,他引:2
Mordaunt CJ Gevao B Jones KC Semple KT 《Environmental pollution (Barking, Essex : 1987)》2005,133(1):25-34
Six major use pesticides (Atrazine, Dicamba, Isoproturon, Lindane, Paraquat and Trifluralin) with differing physico-chemical properties were evaluated for the significance of 'bound' or non extractable residue formation. Investigations were carried out in purpose-built microcosms where mineralization, volatilisation, 'soil water' extractable and organic solvent extractable residues could be quantified. Extractable residues were defined as those accessible by sequential extraction where the solvent used became increasingly non-polar. Dichloromethane was the 'harshest' solvent used at the end of the sequential extraction procedure. (14)C-labelled volatilised and (14)CO(2) fractions were trapped on exit from the microcosm. The pesticides were categorised into 3 classes based on their behaviour. (i) Type A (Atrazine, Lindane and Trifluralin) in which ring degradation was limited as was the formation of non-extractable residues; the remainder of the (14)C-activity was found in the extractable fraction. (ii) Type B (Dicamba and Isoproturon) in which approximately 25% of the (14)C-activity was mineralised and a large portion was found in the non-extractable fraction after 91 days. Finally, Type C (Paraquat) in which almost all of the (14)C-activity was quickly incorporated into the non-extractable fraction. The implications of the data are discussed, with respect to the variability and significance of regulatory aspects of non-extractable residues. 相似文献
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This paper uses an environmental partitioning model to evaluate the concentration of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) in various environmental media. These concentrations are then used to estimate the amount of TCDD entering the food chain and the average daily intake of TCDD by the general population of the US. The food chain accounts for 98% of human exposure to TCDD. The model estimated the average daily intake of TCDD to be 0.05 ng/day. 相似文献
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