The invasion of non-native plants in the Wyoming Basins Ecoregional Assessment (WBEA) area is a m... more The invasion of non-native plants in the Wyoming Basins Ecoregional Assessment (WBEA) area is a major eco- nomic and ecological stress, with invasions thought to be hastened by energy develop- ments. Given the potential impacts of non- native invasive plants and the rapid chang- es in land use in the WBEA, broad-scale assessments and predictive models of non- native invasive plant distribution are need- ed. Using this information, the current ex- tent of populations for targeting treatment and monitoring can be identified, the habi- tat affinities for forecasting where weeds may establish next determined, and the re- sponses to individual human disturbances (such as energy developments) predicted. To address these needs, we conducted veg- etation surveys across the WBEA area at 317 individual survey blocks (five plots per survey block) during the summers of 2005 and 2006. Survey blocks were stratified by both human disturbance and habitat pro- ductivity; in each of five plots per su...
Objectives We aimed to develop and evaluate practical methods to estimate species richness and oc... more Objectives We aimed to develop and evaluate practical methods to estimate species richness and occupancy of diverse taxonomic groups across space and time and in diverse ecosystems. As reflected in the statement of need to which this project responded, our work is relevant to the needs of the Department of Defense (DoD) to assess and monitor native species and to evaluate the potential effects of land use and management actions on native species. Species richness, or the number of native species, is a common surrogate measure of ecosystem status. Occupancy, the probability that a given location is occupied by a species, can serve as a surrogate measure of the species’ abundance, which in turn is related to probability of persistence. This project addressed five major objectives consistent with the primary aim. First, we assessed relations between environmental variables and species richness at nested spatial extents. Second, we developed guidelines for periodicity of sampling. Third...
The Wyoming Basins Ecoregional Assessment (WBEA) area in the western United States contains a num... more The Wyoming Basins Ecoregional Assessment (WBEA) area in the western United States contains a number of important land cover types, including nearly one-fourth of the sagebrush (Artemisia spp.) in North America. Although relatively unap-preciated until recent decades, the broad open landscapes dominated by sagebrush communities have received increasing attention for their ecological value and the resources that they contain (Knick and Con-nelly 2011). As many as 350 wildlife species depend on sagebrush ecosystems for all or part of their life requirements (Wisdom et al. 2005a). Within the WBEA, intact sagebrush landscapes provide an important stronghold for populations of greater sage-grouse (Centrocercus urophasianus), recently listed as a candidate species under the Endangered Species Act (U.S. Department of the Interior 2010). Numerous other plant and vertebrate species of state or national concern also occur within the WBEA study area (Ch. 2). Conserving sagebrush ecosystems is ...
Management of medium to large-sized terrestrial mammals (Antilo- capridae, Canidae, Cervidae, Lep... more Management of medium to large-sized terrestrial mammals (Antilo- capridae, Canidae, Cervidae, Leporidae, Mustelidae, Ochotonidae) in the western United States is multifaceted and complex. Species in this group generally are charis- matic and provide economic opportunities, although others are considered a nuisance at one extreme or are listed as species of conservation concern at the other. Un- derstanding the relative influence of land cover, habitat fragmentation, and human land use on their distribution during the breeding season is imperative to inform management decisions on land use and conservation planning for these species. We surveyed medium to large-sized sage- brush (Artemisia spp.)-associated mammal species in 2005 and 2006 on 141 random transects (mean length = 1.1 km) in the Wyoming Basins, an area undergoing rap- id land cover transformation due to human actions including energy development. Overall, we observed 10 species but only obtained enough observations of pro...
... Cameron L. Aldridge, Steven E. Hanser, Scott E. Nielsen, Matthias Leu, Brian S. Cade, D. Joan... more ... Cameron L. Aldridge, Steven E. Hanser, Scott E. Nielsen, Matthias Leu, Brian S. Cade, D. Joanne Saher, and Steven T. Knick ... There is a growing body of research on habitat relationships for sagebrush (Artemisia spp.)-obligate birds at both lo-cal (Wiens and Rotenberry 1985 ...
With species increasingly imperiled due to anthropogenic activities, conservation practitioners a... more With species increasingly imperiled due to anthropogenic activities, conservation practitioners are tasked with determining conservation priorities to make the best use of limited resources. One way of setting priorities is to categorize species based on risk of extinction. The United States' Endangered Species Act (ESA) has two listing statuses into which imperiled species are placed to receive protections: threatened or endangered. Our objective was to identify differences between threatened and endangered (T&E) species beyond what is outlined in their ESA definitions. For 6 broad‐resolution threats (habitat modification, overutilization, pollution, species‐species interactions, environmental stochasticity, and demographic stochasticity), we investigated whether there is a difference in the number and types of threats which impacted T&E species at the time of their listing. We found that threatened (x̄ = 2.9, SD = 1.4) and endangered (x̄ = 3.0, SD = 1.1) species faced a similar number of threats at time of their listing. The only broad‐resolution threat that impacted endangered species more than threatened species was demographic stochasticity, with endangered species being 2.1 times (95% CI = 1.5–2.8) more likely to be impacted than threatened species. We examined demographic stochasticity by breaking it down into finer‐resolution threats to identify additional differences between T&E species. We found 4 finer‐resolution demographic stochasticity threats (few individuals in one population, few individuals in multiple populations, lack of reproduction, and genetic loss) to be strong predictors of endangered status. The similarities in the number and types of broad‐resolution threats faced by T&E species indicated that they are equally conservation reliant.
The invasion of non-native plants in the Wyoming Basins Ecoregional Assessment (WBEA) area is a m... more The invasion of non-native plants in the Wyoming Basins Ecoregional Assessment (WBEA) area is a major eco- nomic and ecological stress, with invasions thought to be hastened by energy develop- ments. Given the potential impacts of non- native invasive plants and the rapid chang- es in land use in the WBEA, broad-scale assessments and predictive models of non- native invasive plant distribution are need- ed. Using this information, the current ex- tent of populations for targeting treatment and monitoring can be identified, the habi- tat affinities for forecasting where weeds may establish next determined, and the re- sponses to individual human disturbances (such as energy developments) predicted. To address these needs, we conducted veg- etation surveys across the WBEA area at 317 individual survey blocks (five plots per survey block) during the summers of 2005 and 2006. Survey blocks were stratified by both human disturbance and habitat pro- ductivity; in each of five plots per su...
Objectives We aimed to develop and evaluate practical methods to estimate species richness and oc... more Objectives We aimed to develop and evaluate practical methods to estimate species richness and occupancy of diverse taxonomic groups across space and time and in diverse ecosystems. As reflected in the statement of need to which this project responded, our work is relevant to the needs of the Department of Defense (DoD) to assess and monitor native species and to evaluate the potential effects of land use and management actions on native species. Species richness, or the number of native species, is a common surrogate measure of ecosystem status. Occupancy, the probability that a given location is occupied by a species, can serve as a surrogate measure of the species’ abundance, which in turn is related to probability of persistence. This project addressed five major objectives consistent with the primary aim. First, we assessed relations between environmental variables and species richness at nested spatial extents. Second, we developed guidelines for periodicity of sampling. Third...
The Wyoming Basins Ecoregional Assessment (WBEA) area in the western United States contains a num... more The Wyoming Basins Ecoregional Assessment (WBEA) area in the western United States contains a number of important land cover types, including nearly one-fourth of the sagebrush (Artemisia spp.) in North America. Although relatively unap-preciated until recent decades, the broad open landscapes dominated by sagebrush communities have received increasing attention for their ecological value and the resources that they contain (Knick and Con-nelly 2011). As many as 350 wildlife species depend on sagebrush ecosystems for all or part of their life requirements (Wisdom et al. 2005a). Within the WBEA, intact sagebrush landscapes provide an important stronghold for populations of greater sage-grouse (Centrocercus urophasianus), recently listed as a candidate species under the Endangered Species Act (U.S. Department of the Interior 2010). Numerous other plant and vertebrate species of state or national concern also occur within the WBEA study area (Ch. 2). Conserving sagebrush ecosystems is ...
Management of medium to large-sized terrestrial mammals (Antilo- capridae, Canidae, Cervidae, Lep... more Management of medium to large-sized terrestrial mammals (Antilo- capridae, Canidae, Cervidae, Leporidae, Mustelidae, Ochotonidae) in the western United States is multifaceted and complex. Species in this group generally are charis- matic and provide economic opportunities, although others are considered a nuisance at one extreme or are listed as species of conservation concern at the other. Un- derstanding the relative influence of land cover, habitat fragmentation, and human land use on their distribution during the breeding season is imperative to inform management decisions on land use and conservation planning for these species. We surveyed medium to large-sized sage- brush (Artemisia spp.)-associated mammal species in 2005 and 2006 on 141 random transects (mean length = 1.1 km) in the Wyoming Basins, an area undergoing rap- id land cover transformation due to human actions including energy development. Overall, we observed 10 species but only obtained enough observations of pro...
... Cameron L. Aldridge, Steven E. Hanser, Scott E. Nielsen, Matthias Leu, Brian S. Cade, D. Joan... more ... Cameron L. Aldridge, Steven E. Hanser, Scott E. Nielsen, Matthias Leu, Brian S. Cade, D. Joanne Saher, and Steven T. Knick ... There is a growing body of research on habitat relationships for sagebrush (Artemisia spp.)-obligate birds at both lo-cal (Wiens and Rotenberry 1985 ...
With species increasingly imperiled due to anthropogenic activities, conservation practitioners a... more With species increasingly imperiled due to anthropogenic activities, conservation practitioners are tasked with determining conservation priorities to make the best use of limited resources. One way of setting priorities is to categorize species based on risk of extinction. The United States' Endangered Species Act (ESA) has two listing statuses into which imperiled species are placed to receive protections: threatened or endangered. Our objective was to identify differences between threatened and endangered (T&E) species beyond what is outlined in their ESA definitions. For 6 broad‐resolution threats (habitat modification, overutilization, pollution, species‐species interactions, environmental stochasticity, and demographic stochasticity), we investigated whether there is a difference in the number and types of threats which impacted T&E species at the time of their listing. We found that threatened (x̄ = 2.9, SD = 1.4) and endangered (x̄ = 3.0, SD = 1.1) species faced a similar number of threats at time of their listing. The only broad‐resolution threat that impacted endangered species more than threatened species was demographic stochasticity, with endangered species being 2.1 times (95% CI = 1.5–2.8) more likely to be impacted than threatened species. We examined demographic stochasticity by breaking it down into finer‐resolution threats to identify additional differences between T&E species. We found 4 finer‐resolution demographic stochasticity threats (few individuals in one population, few individuals in multiple populations, lack of reproduction, and genetic loss) to be strong predictors of endangered status. The similarities in the number and types of broad‐resolution threats faced by T&E species indicated that they are equally conservation reliant.
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