R package developed to support study design for acoustic bat surveys with imperfect detection mis... more R package developed to support study design for acoustic bat surveys with imperfect detection misidentification
In many, formerly fishless lakes in western North America, trout have been introduced for recreat... more In many, formerly fishless lakes in western North America, trout have been introduced for recreational fishing, replacing native amphibians as top predators. Trout are associated with reducing the abundance of amphibians and have extirpated populations of long-toed salamanders (Ambystoma macrodactylum). Salamanders and trout may coexist in some lakes, as larvae often are able to alter foraging behavior, use of open water, and time in refugia in response to predatory cues. However, salamanders are still subject to attacks and may have different body morphology in environments with fish. We sought to estimate minimum population sizes of long-toed salamanders, as well as investigate indirect effects of fish on salamander morphology. We sampled lakes with and without fish in northwestern Montana during the summers of 2012 and 2013. We caught salamander larvae using minnow traps, took several body measurements, and compared capture rates and morphological measurements between lakes with ...
Hoary marmots (Marmota caligata) can be found in boulder fields throughout alpine areas of wester... more Hoary marmots (Marmota caligata) can be found in boulder fields throughout alpine areas of western Montana, but we know little about their specific habitat requirements. We sought to determine the influence of boulder size on occupancy and detection probability of the hoary marmot during occupancy surveys. We conducted 532 visual occupancy surveys of 147 sites between June and September 2015. We estimated variation in occupancy and detection probability based on four size categories of boulders. We did not detect differences in occupancy of marmots as the size composition of boulders changed. Detection probability was most influenced by medium and large boulders. Probability of detecting a marmot was 38% (95% CI=0.24–0.53) when medium boulders were absent, but decreased to 3% as the proportion of medium boulders increased to 60% (95% CI=0–0.15). Probability of detecting a marmot was 16% when large boulders were absent (95% CI=0.1–0.24) but increased to 92% when just 5% of the site c...
Old World bluestem grasses (OWBs, e.g., Bothriochloa, Dichanthium spp.) have become dominant thro... more Old World bluestem grasses (OWBs, e.g., Bothriochloa, Dichanthium spp.) have become dominant throughout the southern and central Great Plains, altering native plant communities with concomitant effects for native wildlife. We examined plant and arthropod communities in areas dominated by native plants and areas dominated by OWBs at the Welder Wildlife Refuge in southern Texas. We sampled vegetation and arthropods on research plots (6 x 9-m, 5 each) every 4 weeks during summer 2011 and 2012. We found, on average, 2 (SE=0.2) more plant species, and 12-13 (SE=1.0) more arthropod species on native plant-dominated plots compared to OWB-dominated plots. Native plant-dominated plots also had 273 (SE=18.8) more individual arthropods in 2011, but 75 (SE=16.6) fewer than OWB-dominant plots in 2012, resulting from a population explosion and crash of woodlice in native plant-dominated plots. We recorded only 1 species of herbivorous arthropod from OWB-dominated plots in 2012; native plant-domin...
Freshwater wetlands support a disproportionately high diversity of species relative to other ecos... more Freshwater wetlands support a disproportionately high diversity of species relative to other ecosystems and they are particularly vulnerable to climate change. Across Grand Teton and Yellowstone National Parks, wetlands represent just 3% of the landscape, yet 70% of Wyoming bird species and all native amphibians in the region use wetlands for some stage of their life. The Greater Yellowstone Inventory and Monitoring Network has monitored amphibians in wetlands since 2006 and found that over 40% of the region’s isolated wetlands are dry in years with above average temperatures and reduced precipitation. Adding novel technologies to these monitoring efforts will increase our understanding of species diversity in wetlands susceptible to drying. We outfitted three wetland sites in Grand Teton National Park with acoustic (i.e., audible and ultrasonic) monitoring technology and wildlife camera traps in summer 2016. We collected data over a four-week period to test the efficacy of automate...
The wolverine is a naturally uncommon species whose conservation and management requires collabor... more The wolverine is a naturally uncommon species whose conservation and management requires collaboration across a large geography. Conservation priorities for wolverines in the western U.S. have been identified as 1) Connectivity, 2) Restorations, and 3) Monitoring. The Western States Wolverine Working Group is a collaborative effort among state, federal, tribal, university, and private organizations that are actively working on these priorities. One element of the conservation program is baseline survey for wolverine occupancy across the 4-states where the species currently occurs – Montana, Wyoming, Idaho, and Washington. The survey uses a grid of 15 x 15 km cells. All cells >50% modelled wolverine habitat were considered for sampling, and a GRTS sample of 180 cells was selected to be surveyed using a standard protocol across the 4-state area during winter 2016-17. A single camera/DNA station was established during November 2016 in each cell and will be run through April 2017. To...
Variation in nutrient allocation can influence the timing of breeding and ultimately reproductive... more Variation in nutrient allocation can influence the timing of breeding and ultimately reproductive output. Time and space constraints might exist, however, if fewer food resources are available to meet the costs of reproduction early during the reproductive season. Here, for the first time, we test whether nutrient allocation strategies for reproduction in a shrub-dependent avian species differs with timing of breeding in different ecoregions: a high-elevation landscape, containing spatially complex vegetation (Rocky Mountains) versus a low-elevation, more homogenous landscape (Great Plains). We analyzed data collected from radio-telemetry and stable isotopes to assess the degree to which endogenous (body) reserves are used for reproduction and whether variation in allocation strategies was associated with time of year, ecoregion, habitat quality (including sagebrush type and plant greenness), or maternal characteristics. Using a Bayesian statistical framework, we found that females relied on a similar amount of endogenous reserves for reproduction in first nesting and renesting attempts. Additionally, endogenous contributions declined more rapidly throughout the nesting season in the Rocky Mountains than in the Great Plains. Individuals in high- and intermediate-elevation sagebrush types in the Rocky Mountains used similar amounts of endogenous reserves, whereas females nesting in low-elevation sagebrush used less. Females nesting at intermediate elevations, which experience the greatest flush of new green vegetation during the nesting season, switched their reliance from endogenous to exogenous sources for reproduction as green vegetation became available during spring. Our study highlights adaptations of a nutrient-allocation strategy across areas with varying levels of resources in time and space in a habitat specialist bird. Nutrient allocation by individuals residing in high-elevation areas favors a strategy that mainly uses nutrients gained from wintering habitats, whereas individuals residing in low-elevat [...]
We analyzed detection/non-detection data from acoustic surveys of bat species in Colorado during ... more We analyzed detection/non-detection data from acoustic surveys of bat species in Colorado during the summers of 2016 and 2017. The goal of this analysis is to create species distribution maps estimating the probability of occupancy across the state for each species. We fit a community occupancy model using both years of data from all the available species. Spatially explicit covariates were included to explain heterogeneity in the probabilities of occupancy and nightly covariates were used to model detection. We also allowed for spatial patterns in the probability of occupancy for each species in order to account for the ranges of many species including only a portion of Colorado. This is also useful for explaining additional spatial variation in the probabilities of occupancy that are not captured with the available covariates. The results of this analysis are provided as a shapefile including the estimates and associated uncertainty in the occupancy predictions across the state.
R package developed to support study design for acoustic bat surveys with imperfect detection mis... more R package developed to support study design for acoustic bat surveys with imperfect detection misidentification
In many, formerly fishless lakes in western North America, trout have been introduced for recreat... more In many, formerly fishless lakes in western North America, trout have been introduced for recreational fishing, replacing native amphibians as top predators. Trout are associated with reducing the abundance of amphibians and have extirpated populations of long-toed salamanders (Ambystoma macrodactylum). Salamanders and trout may coexist in some lakes, as larvae often are able to alter foraging behavior, use of open water, and time in refugia in response to predatory cues. However, salamanders are still subject to attacks and may have different body morphology in environments with fish. We sought to estimate minimum population sizes of long-toed salamanders, as well as investigate indirect effects of fish on salamander morphology. We sampled lakes with and without fish in northwestern Montana during the summers of 2012 and 2013. We caught salamander larvae using minnow traps, took several body measurements, and compared capture rates and morphological measurements between lakes with ...
Hoary marmots (Marmota caligata) can be found in boulder fields throughout alpine areas of wester... more Hoary marmots (Marmota caligata) can be found in boulder fields throughout alpine areas of western Montana, but we know little about their specific habitat requirements. We sought to determine the influence of boulder size on occupancy and detection probability of the hoary marmot during occupancy surveys. We conducted 532 visual occupancy surveys of 147 sites between June and September 2015. We estimated variation in occupancy and detection probability based on four size categories of boulders. We did not detect differences in occupancy of marmots as the size composition of boulders changed. Detection probability was most influenced by medium and large boulders. Probability of detecting a marmot was 38% (95% CI=0.24–0.53) when medium boulders were absent, but decreased to 3% as the proportion of medium boulders increased to 60% (95% CI=0–0.15). Probability of detecting a marmot was 16% when large boulders were absent (95% CI=0.1–0.24) but increased to 92% when just 5% of the site c...
Old World bluestem grasses (OWBs, e.g., Bothriochloa, Dichanthium spp.) have become dominant thro... more Old World bluestem grasses (OWBs, e.g., Bothriochloa, Dichanthium spp.) have become dominant throughout the southern and central Great Plains, altering native plant communities with concomitant effects for native wildlife. We examined plant and arthropod communities in areas dominated by native plants and areas dominated by OWBs at the Welder Wildlife Refuge in southern Texas. We sampled vegetation and arthropods on research plots (6 x 9-m, 5 each) every 4 weeks during summer 2011 and 2012. We found, on average, 2 (SE=0.2) more plant species, and 12-13 (SE=1.0) more arthropod species on native plant-dominated plots compared to OWB-dominated plots. Native plant-dominated plots also had 273 (SE=18.8) more individual arthropods in 2011, but 75 (SE=16.6) fewer than OWB-dominant plots in 2012, resulting from a population explosion and crash of woodlice in native plant-dominated plots. We recorded only 1 species of herbivorous arthropod from OWB-dominated plots in 2012; native plant-domin...
Freshwater wetlands support a disproportionately high diversity of species relative to other ecos... more Freshwater wetlands support a disproportionately high diversity of species relative to other ecosystems and they are particularly vulnerable to climate change. Across Grand Teton and Yellowstone National Parks, wetlands represent just 3% of the landscape, yet 70% of Wyoming bird species and all native amphibians in the region use wetlands for some stage of their life. The Greater Yellowstone Inventory and Monitoring Network has monitored amphibians in wetlands since 2006 and found that over 40% of the region’s isolated wetlands are dry in years with above average temperatures and reduced precipitation. Adding novel technologies to these monitoring efforts will increase our understanding of species diversity in wetlands susceptible to drying. We outfitted three wetland sites in Grand Teton National Park with acoustic (i.e., audible and ultrasonic) monitoring technology and wildlife camera traps in summer 2016. We collected data over a four-week period to test the efficacy of automate...
The wolverine is a naturally uncommon species whose conservation and management requires collabor... more The wolverine is a naturally uncommon species whose conservation and management requires collaboration across a large geography. Conservation priorities for wolverines in the western U.S. have been identified as 1) Connectivity, 2) Restorations, and 3) Monitoring. The Western States Wolverine Working Group is a collaborative effort among state, federal, tribal, university, and private organizations that are actively working on these priorities. One element of the conservation program is baseline survey for wolverine occupancy across the 4-states where the species currently occurs – Montana, Wyoming, Idaho, and Washington. The survey uses a grid of 15 x 15 km cells. All cells >50% modelled wolverine habitat were considered for sampling, and a GRTS sample of 180 cells was selected to be surveyed using a standard protocol across the 4-state area during winter 2016-17. A single camera/DNA station was established during November 2016 in each cell and will be run through April 2017. To...
Variation in nutrient allocation can influence the timing of breeding and ultimately reproductive... more Variation in nutrient allocation can influence the timing of breeding and ultimately reproductive output. Time and space constraints might exist, however, if fewer food resources are available to meet the costs of reproduction early during the reproductive season. Here, for the first time, we test whether nutrient allocation strategies for reproduction in a shrub-dependent avian species differs with timing of breeding in different ecoregions: a high-elevation landscape, containing spatially complex vegetation (Rocky Mountains) versus a low-elevation, more homogenous landscape (Great Plains). We analyzed data collected from radio-telemetry and stable isotopes to assess the degree to which endogenous (body) reserves are used for reproduction and whether variation in allocation strategies was associated with time of year, ecoregion, habitat quality (including sagebrush type and plant greenness), or maternal characteristics. Using a Bayesian statistical framework, we found that females relied on a similar amount of endogenous reserves for reproduction in first nesting and renesting attempts. Additionally, endogenous contributions declined more rapidly throughout the nesting season in the Rocky Mountains than in the Great Plains. Individuals in high- and intermediate-elevation sagebrush types in the Rocky Mountains used similar amounts of endogenous reserves, whereas females nesting in low-elevation sagebrush used less. Females nesting at intermediate elevations, which experience the greatest flush of new green vegetation during the nesting season, switched their reliance from endogenous to exogenous sources for reproduction as green vegetation became available during spring. Our study highlights adaptations of a nutrient-allocation strategy across areas with varying levels of resources in time and space in a habitat specialist bird. Nutrient allocation by individuals residing in high-elevation areas favors a strategy that mainly uses nutrients gained from wintering habitats, whereas individuals residing in low-elevat [...]
We analyzed detection/non-detection data from acoustic surveys of bat species in Colorado during ... more We analyzed detection/non-detection data from acoustic surveys of bat species in Colorado during the summers of 2016 and 2017. The goal of this analysis is to create species distribution maps estimating the probability of occupancy across the state for each species. We fit a community occupancy model using both years of data from all the available species. Spatially explicit covariates were included to explain heterogeneity in the probabilities of occupancy and nightly covariates were used to model detection. We also allowed for spatial patterns in the probability of occupancy for each species in order to account for the ranges of many species including only a portion of Colorado. This is also useful for explaining additional spatial variation in the probabilities of occupancy that are not captured with the available covariates. The results of this analysis are provided as a shapefile including the estimates and associated uncertainty in the occupancy predictions across the state.
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