Proceedings of the Seventh Mountain Lion Workshop

136
DEFINING AND DELINEATING DE FACTO REFUGIA: A PRELIMIARY ANALYSIS
OF THE SPATIAL DISTRIBUTION OF COUGAR HARVEST IN UTAH AND
IMPLICATIONS FOR CONSERVATION
DAVID C. STONER, Utah State University, Dept. of Forest, Range, and Wildlife Sciences,
5230 Old Main Hill, Logan, UT 84322-5230, USA, email: dstoner@cc.usu.edu
MICHAEL L. WOLFE, Utah State University, Dept. of Forest, Range, and Wildlife Sciences,
5230 Old Main Hill, Logan, UT 84322-5230, USA, email: mlwolfe@cnr.usu.edu
Abstract: Cougars (Puma concolor) in Utah are managed at two scales, often with differing
objectives. The statewide population is managed for persistence and sustainable hunting
opportunities, while at the finer scale of an individual management unit, a sub-population may be
managed to accomplish density reductions, depending on local priorities. However, cougars
have large and variable spatial requirements, and management unit boundaries may not coincide
with actual demes. Compounding these constraints, the lack of cost-effective and reliable
enumeration techniques increases the risk of inadvertent over-harvest. Current research suggests
that for species difficult to enumerate, greater emphasis be placed on metapopulation-scale
management in order to minimize the effects of uncertainties with respect to demography and
dispersal behavior. Because harvest is the primary variable that managers can manipulate and
measure, it is important to understand how recruitment patterns in minimally exploited
populations may influence the persistence and recovery of heavily exploited populations. In this
paper we discuss some of the factors that account for the spatial distribution of harvest and how
this information can be used to develop management strategies in the absence of census data.
We used 6 years of radio-telemetry data from a lightly exploited population in the Oquirrh
Mountains of north-central Utah to quantify the effect of a small sanctuary (480 km²) on cougar
survivorship, fecundity, and dispersal. We then mapped the locations of cougars harvested
across the state from 1996-2001, and attempted to: (1) identify the factors that influence these
patterns, and (2) determine the size and distribution of potential harvest sinks and de facto
refugia in the state. Finally, we identified habitat patches on the periphery of the state that
straddle management jurisdictions, representing areas of possible inter-state cooperation. We
recommend that managers consider a metapopulation perspective and attempt to distribute
harvest pressure in a spatially and ecologically relevant manner. In the absence of large (2400
km²), contiguous refugia, small sanctuaries adjacent to areas of high exploitation may be mapped
and utilized as a deterrent against potential over-exploitation.
PROCEEDINGS OF THE SEVENTH MOUNTAIN LION WORKSHOP