by Robert R. Truax and Thomas M. Gehring
Rapid assessment of wild animal population abundance is problematic, particularly for rare, cryptic felid species. However, estimates of population abundance are critical for effectively targeting conservation and management actions. Traditional mark-release-recapture (MRR) methods require recapturing hundreds of animals—often necessitating the capture of thousands of animals initially (Manning et al. 1995). In a traditional MRR framework, it is likely that at least some individuals will experience pain and distress during capture, handling, and marking. Non-invasive population estimation methods are preferred, particularly for threatened or endangered felid species.
Many carnivore species use scats for scent communication among conspecifics, thereby leaving an accumulation of scats at relatively predictable locations (latrines) within their territories. Among certain felids (e,g., Iberian lynx, Lynx pardinus; ocelot, Leopardus pardalis), latrines may be especially important for information transfer during breeding seasons. Bobcats (Lynx rufus) also establish latrines within their home ranges; however, there is a dearth of information as to the function that these latrines play in the ecology of this species.
The purpose of this study, funded by AWI’s Christine Stevens Wildlife Award, is to collect baseline data that may help in determining the functional role that latrines play in the social structure and ecology of bobcats by using remote camera trapping methods and DNA scat analysis. Another facet of this project is to create artificial latrine sites and observe the behavioral response (via remote camera trapping methods) to a newly introduced bobcat scat into an established bobcat territory. The hypothesis is that latrines will be visited more by male bobcats during the breeding season and more by females during the non-breeding season. Wassmer, et al. (1988) noted that scent marking (scrapes, urine and fecal depositions) in females peaked during the breeding period, accompanied by a reduction in scent marking in periods of late gestation and in the presence of young litters. Basic knowledge of bobcat use of latrine sites will be particularly useful for developing an artificial latrine survey protocol for estimating population abundance.
As of May 2012, seven latrines are currently being monitored for visitation frequency by bobcats. From the seven latrines, 35 bobcat captures were recorded using remote camera trapping techniques. Analysis of the two initial latrine sites with the most complete data sets indicate that latrine visitation occurs 85 percent of the time during non-breeding seasons (April-August), with an average visitation rate of 0.051 visits/day. Remote camera monitoring of additional latrine sites is projected to continue through August 2012. Current research efforts are being focused on identifying the sex of individuals based on genotyping of DNA obtained via scat and by photographic analysis of captured individuals.
Further data collection will progress from the funding by AWI. Once data collection is complete, the efficacy of artificial latrine sites as a population monitoring tool for felids will be assessed, as well as a more complete picture of the role latrines play in the social ecology of bobcats.
Manning T, W. D. Edge, and J. O. Wolff. 1995. Evaluating population-size estimators—an empirical-approach. Journal of Mammalogy 76:1149-1158.
Wassmer, D. A., D. D. Guenther, and J. N. Layne. 1988. Ecology of the bobcat in South-central Florida. Bulletin of Florida State Museum of Biological Science 33:159-228.