Publication Date
12-2024
Date of Final Oral Examination (Defense)
10-11-2024
Type of Culminating Activity
Thesis
Degree Title
Master of Science in Biology
Department
Biological Sciences
Supervisory Committee Chair
Jennyffer Cruz, Ph.D.
Supervisory Committee Member
Jennifer Forbey, Ph.D.
Supervisory Committee Member
Julie Heath, Ph.D.
Abstract
Animals are facing an unprecedented rate of environmental change including extreme rates of habitat loss. Animals may adjust their distribution or behaviors to compensate for changes in food resources and cover associated with habitat loss. We studied how black-tailed jackrabbits (Lepus californicus) in a Western U.S. dryland ecosystem used vegetation types that provide different levels of food resources and protection. We estimated black-tailed jackrabbit density in 2022 and 2023 within the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA) using repeated spotlight transects and an N-mixture model. Black-tailed jackrabbit abundance increased with increasing shrub cover in 2022 and 2023 and increased also with increasing perennial biomass in 2023. Differences between year effects may have been related to weather conditions. Higher abundances in 2022 (a dry year) compared to 2023 (near-normal, non-drought year with more availability of herbaceous biomass) indicate a potential lag effect in population decline. There is some local anecdotal and faint evidence from this study, supporting NCA black-tailed jackrabbit population decline compared to historic raw densities (this study, Fig. 5; Smith and Nydegger 1985; Knick and Dyer 1997). However, more research (exceeding 2 years) will be needed to understand if we are capturing evidence of black-tailed jackrabbit population abundance cycle dampening or drastic decline. Our findings suggest that shrub-dominated habitats with perennial herbaceous vegetation availability support higher abundances of black-tailed jackrabbits.
DOI
10.18122/td.2399.boisestate
Recommended Citation
Camacho, Leticia MariSol, "Black-Tailed Jackrabbit Density in Morley Nelson Snake River Birds of Prey National Conservation Area Highlights the Importance of Native Shrubs" (2024). Boise State University Theses and Dissertations. 2399.
10.18122/td.2399.boisestate