Recipient Organization
UNIVERSITY OF NEVADA
(N/A)
RENO,NV 89557
Performing Department
Natural Resources & Environmental Sciences
Non Technical Summary
In Nevada, cougar habitat encompasses a basin-range system where mountains of suitable cougar habitat are separated by broad expanses of desert basins. This basin and range topography combined with the unequal harvest of cougars across the landscape likely supports a source-sink metapopulation where the long-term survival of subpopulations is dependent on the movement of cougars between habitat patches (Logan and Sweanor 2001). Furthermore, source-sink dynamics between subpopulations within Nevada where they are hunted and California where they are protected is likely. Abundant contiguous mountain lion habitat within California combined with the protected status in the state makes it likely that California operates as a source population for Nevada. However, the extent that mountain lions migrate between California and Nevada is uncertain. Failure of managers to recognize metapopulation structure can lead to management errors by assuming a constant level of harvest can be sustained across the landscape without considering the role of immigration in sustaining populations (CMGWG 2005). Therefore, the identification of source and sink subpopulations and the maintenance of linkages between them are essential for the long-term maintenance of cougar populations and scientifically justifiable harvest quotas. We are addressing these questions with the most contemporary genetic techniques available
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Our objectives with this project are to: 1) model the genetic structure of cougars within Nevada to identify distinct subpopulations, 2) Model source-sink metapopulation dynamics between identified sub-populations, 3) Determine the relative influence of environmental variables (i.e., prey densities, habitat type), human impact (human population growth, housing density, road density, hunting pressure, etc.), immigration (source/sink dynamics, connectivity) and other potentially relevant factors in regulating cougar distribution and abundance in different areas of Nevada. Test the resulting probability-of-use model accuracy with empirical data obtained from a subset of collared cougars, 4) Model the most likely movement paths that cougars use to move between identified interacting sub-populations throughout Nevada and subsequently test corridor model accuracy using empirical data from collared cougars captured in Nevada, and 5) Determine predation rates and prey selection of cougars in Nevada.
Project Methods
We are addressing these objectives with a combination of genetic analysis, stable isotope dietary analysis, and GPS-satellite tracking technology. Genetic analysis is currently being conducted at the University of Nevada, Reno on over 800 tissue samples obtained from hunter harvested cougars throughout Nevada and eastern California. In addition, we are currently capturing cougars in western Nevada and fitting them with GPS-satellite collars. Study Area While genetic analysis and connectivity modelling encompass the state of Nevada and eastern California, cougars are currently being captured and collared in the western corner of the state within the Great Basin and Lake Tahoe Basin (figure 1). Capture efforts are focused in the Carson Range, Virginia Range, and Pine Nut Mountains. GPS-satellite data from collars will be used even when cougars leave the study area where captures are focused. Animal Capture GPS-satellite collars are being fitted on cougars weighing >32 kg captured within the study area with a goal of >24 adult study animals, monitored for at least a year. We are using professional houndsmenn and trained hounds to track and capture cougars as well as box traps. Upon capture cougars are immobilized with 2 mg/kg ketamine plus 0.075 mg/kg medetomidine using a blow dart projector or dart rifle and are reversed with 0.3 mg/kg atipamezole. Age is estimated using dentition characteristics such as tooth wear and gum recession. An ear tag and tattoo with a unique ID number is placed in the ear. Between ten and thirty milliliters of blood is drawn via jugular venepuncture. All kittens born to collard females will be collared with expandable breakaway collars to estimate female reproductive output, kitten survival rates, dispersal age and dispersal movements. Collection and Preparation of Genetic Material We extracted nuclear DNA and amplified 14 microsatellites from over 800 tissue samples obtained from cougars harvested by hunters throughout Nevada between 2004-2010 and 30 from California Wildlife Services Depredations. We conducted fragment analysis on PCR products of the samples using an Applied Biosystems (ABI) 3730 DNA Analyzer (Nevada Genomics Center) and associated GENEMAPPER software (version 3.7). We are currently analyzing these genetic data to determine population substructure of cougars in Nevada and movement rates between populations.