Location: Great Basin Rangelands Research
Title: Identification of source-sink dynamics in mountain lions of the Great Basin Authors
|Andreasen, Alyson -|
|Stewart, Kelley -|
|Beckmann, Jon -|
|Forister, Matthew -|
Submitted to: Molecular Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 2, 2012
Publication Date: August 31, 2012
Citation: Andreasen, A.M., Stewart, K.M., Longland, W.S., Beckmann, J.P., Forister, M.L. 2012. Identification of source-sink dynamics in mountain lions of the Great Basin. Molecular Ecology 21. DOI: 10.1111/4.1365-294x.2012.05740.x. Interpretive Summary: Natural and artificial man-made boundaries have been shown to affect populations of many wildlife species that move over long distances. It is difficult to study how boundaries affect wildlife movement patterns, especially for uncommon and secretive species, such as mountain lions. However, recent developments in using genetic patterns of populations to infer movement patterns within and between different populations offer an approach that does not rely on intensive tracking of animals in nature. Using tissue samples from 739 Nevada mountain lions killed by hunters since 2004 and a much smaller sample of mountain lion tissue from eastern California, we used such techniques to identify two main mountain lion populations within the state of Nevada and five sub-populations that seldom exchange any animals. Sub-populations of mountain lions that enjoy the protection of refuges where hunting is prohibited produced the majority of surplus animals that moved between different populations or sub-populations. The study thus showed that hunting pressure has had a major effect in maintaining mountain lion populations in Nevada.
Technical Abstract: Understanding population boundaries and movement rates in the field for species that are cryptic and occur at low densities is often extremely difficult and logistically prohibitive; however genetic techniques may offer insights that have previously been unattainable. We analyzed thirteen microsatellite loci for 739 mountain lions (Puma concolor) using muscle tissue samples from individuals in the Great Basin throughout Nevada and the eastern Sierra Nevada mountain range to test the hypothesis that heterogeneous hunting pressure results in source-sink dynamics at the landscape scale. We used a combination of non-spatial and spatial model-based Bayesian clustering methods to identify genetic populations. We then used a recently developed Bayesian multilocus genotyping method to estimate asymmetrical rates of contemporary movement between those sub-populations and to identify source and sink populations. We identified 2 populations at the highest level of genetic structuring with a total of 5 subpopulations in the Great Basin of Nevada and the eastern Sierra Nevada range. Our results suggest that source-sink dynamics occur at landscape scales for wide-ranging species, such as mountain lions, and that source populations may be those that are under relatively less hunting pressure and that occupy refugia.