Matching Items (2)
Description
The Arizona toad (Anaxyrus microscaphus) is unique among bufonids because they primarily breed in streams of Arizona, New Mexico, Utah, and Nevada. Arizona toad is a species of conservation concern throughout their range. The non-native northern crayfish (Orconectes virilis) are opportunistic omnivores implicated in the declines of other native aquatic species. I wanted to determine occupancy, habitat use, and species interactions of the Arizona toad throughout its range Visual encounter surveys (VES) were completed by ASU and natural resource agency partners in the summers of 2021 and 2022 (n = 232) throughout Arizona toad range in Arizona. I used VES data and crayfish occurrence records, to determine interactions between the two species. I used broadscale environmental variables (1 km resolution) from WorldClim and EarthEnv to evaluate a relationship with Arizona toad occupancy across transects. These broadscale variables included bioclimatic variables, measures of habitat heterogeneity, measures of solar radiation, and topographic variables. In 2022 I collected fine-scale habitat data evaluating available vegetation cover and substrate composition within paired habitat plots. Fine-scale variables included canopy cover, substrate type, vegetation cover, and water depth. I applied multiple occupancy modeling approaches. Single-species model results found low toad occupancy, but high detection, as this is a rare species. Multi-species results showed no positive or negative relationship between Arizona toad and northern crayfish for both seasons. Two principal component analyses (PCA) were run on broadscale environmental variables and fine-scale habitat variables for 2021 and 2022, respectively, creating new synthetic variables for use in analysis. In 2021, the broadscale components were added to the single-species occupancy models and the top model included bioclimatic variables related to annual temperature range and precipitation. Arizona toad occupancy is lower with extreme hot temperatures and less precipitation. A logistic regression was run with the fine-scale habitat variables and the top model included PC1 and PC3. PC1 described elements related to riparian complexity, while PC3 described elements related to algae presence, including attached to cobble substrate. Arizona Toad select for certain habitats including canopy cover, shallow water, algae cover, and pebble cover. It is important to maintain riparian area habitat complexity and conserve habitat for the Arizona toad, a riparian stream specialist.
ContributorsMontgomery, Brett Joseph (Author) / Bateman, Heather L (Thesis advisor) / Albuquerque, Fabio S (Committee member) / Bogan, Michael T (Committee member) / Arizona State University (Publisher)
Created2023
Description
Land use change driven by human population expansion continues to influence
the integrity and configuration of riparian corridors worldwide. Wildlife viability in semi-arid regions depend heavily on the connectivity of riparian corridors, since water is the primary limiting resource. The Madrean Archipelago in northern Mexico and southwestern United States (US) is a biodiversity hotspot that supports imperiled wildlife like jaguar (Panthera onca) and ocelot (Leopardus pardalis). Recent and ongoing infrastructure developments in the historically understudied US-México borderlands region, such as the border wall and expansion of Federal Highway 2, are altering wildlife movement and disconnecting essential habitat.
I used wildlife cameras to assess species occupancy, abundance, and related habitat variables affecting the use of washes as corridors for mammals in semi-arid Los Ojos (LO), a private ranch within a 530 km2 priority conservation area in Sonora, México located south of the border and Federal Highway 2. From October 2018 to April 2019, I deployed 21 wildlife cameras in five different riparian corridors within LO. I used single- season occupancy models and Royal Nichols abundance models to explore the relationship between habitat variables and use of riparian corridors by mammal communities of conservation concern within this region.
Twenty-one mammal species were recorded in the study area, including American black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus) and the first sighting of jaguar (Panthera onca) in this region in 25 years. For the 11 medium- and large-bodied mammals recorded, habitat variables related to perennial river characteristics (distance to river, weekly water, and site width) and remoteness (distance from highway, elevation, and NDVI) were important for occupancy, but the direction of the relationship varied by species. For commonly observed species such as mountain lion (Puma concolor) and white-nosed coati (Nasua narica), topographic variety was highly informative for species abundance. These results highlight the importance of habitat diversity when identifying corridors for future protection to conserve wildlife communities in semi-arid regions. Additionally, this study provides robust evidence in support of mitigation measures (e.g. funnel fencing, over- or under- passes) along Federal Highway 2, and other barriers such as the border wall, to facilitate wildlife connectivity.
the integrity and configuration of riparian corridors worldwide. Wildlife viability in semi-arid regions depend heavily on the connectivity of riparian corridors, since water is the primary limiting resource. The Madrean Archipelago in northern Mexico and southwestern United States (US) is a biodiversity hotspot that supports imperiled wildlife like jaguar (Panthera onca) and ocelot (Leopardus pardalis). Recent and ongoing infrastructure developments in the historically understudied US-México borderlands region, such as the border wall and expansion of Federal Highway 2, are altering wildlife movement and disconnecting essential habitat.
I used wildlife cameras to assess species occupancy, abundance, and related habitat variables affecting the use of washes as corridors for mammals in semi-arid Los Ojos (LO), a private ranch within a 530 km2 priority conservation area in Sonora, México located south of the border and Federal Highway 2. From October 2018 to April 2019, I deployed 21 wildlife cameras in five different riparian corridors within LO. I used single- season occupancy models and Royal Nichols abundance models to explore the relationship between habitat variables and use of riparian corridors by mammal communities of conservation concern within this region.
Twenty-one mammal species were recorded in the study area, including American black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus) and the first sighting of jaguar (Panthera onca) in this region in 25 years. For the 11 medium- and large-bodied mammals recorded, habitat variables related to perennial river characteristics (distance to river, weekly water, and site width) and remoteness (distance from highway, elevation, and NDVI) were important for occupancy, but the direction of the relationship varied by species. For commonly observed species such as mountain lion (Puma concolor) and white-nosed coati (Nasua narica), topographic variety was highly informative for species abundance. These results highlight the importance of habitat diversity when identifying corridors for future protection to conserve wildlife communities in semi-arid regions. Additionally, this study provides robust evidence in support of mitigation measures (e.g. funnel fencing, over- or under- passes) along Federal Highway 2, and other barriers such as the border wall, to facilitate wildlife connectivity.
ContributorsRagan, Kinley (Author) / Hall, Sharon J (Thesis advisor) / Schipper, Jan (Thesis advisor) / Bateman, Heather L (Committee member) / Arizona State University (Publisher)
Created2020