SREL Reprint #3360

Optimization of scat detection methods for a social ungulate, the wild pig, and experimental evaluation of factors affecting detection of scat

David A. Keiter1,2, Fred L. Cunningham3, Olin E. Rhodes, Jr.1,4, Brian J. Irwin5,
and James C. Beasley1,2

1Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
2D. B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
3National Wildlife Research Center, United States Department of Agriculture Animal and
Plant Health Inspection Service, Starkville, Mississippi, USA
4Odum School of Ecology, University of Georgia, Athens, Georgia, USA
5U. S. Geological Survey, Georgia Cooperative Fish and Wildlife Research Unit, D. B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA

Abstract: Collection of scat samples is common in wildlife research, particularly for genetic capture-mark-recapture applications. Due to high degradation rates of genetic material in scat, large numbers of samples must be collected to generate robust estimates. Optimization of sampling approaches to account for taxa-specific patterns of scat deposition is, therefore, necessary to ensure sufficient sample collection. While scat collection methods have been widely studied in carnivores, research to maximize scat collection and noninvasive sampling efficiency for social ungulates is lacking. Further, environmental factors or scat morphology may influence detection of scat by observers. We contrasted performance of novel radial search protocols with existing adaptive cluster sampling protocols to quantify differences in observed amounts of wild pig (Sus scrofa) scat. We also evaluated the effects of environmental (percentage of vegetative ground cover and occurrence of rain immediately prior to sampling) and scat characteristics (fecal pellet size and number) on the detectability of scat by observers. We found that 15- and 20-m radial search protocols resulted in greater numbers of scats encountered than the previously used adaptive cluster sampling approach across habitat types, and that fecal pellet size, number of fecal pellets, percent vegetative ground cover, and recent rain events were significant predictors of scat detection. Our results suggest that use of a fixed-width radial search protocol may increase the number of scats detected for wild pigs, or other social ungulates, allowing more robust estimation of population metrics using noninvasive genetic sampling methods. Further, as fecal pellet size affected scat detection, juvenile or smaller-sized animals may be less detectable than adult or large animals, which could introduce bias into abundance estimates. Knowledge of relationships between environmental variables and scat detection may allow researchers to optimize sampling protocols to maximize utility of noninvasive sampling for wild pigs and other social ungulates.

SREL Reprint #3360

Keiter, D. A., F. L. Cunningham, O. E. Rhodes Jr., B. J. Irwin, and J. C. Beasley. 2016. Optimization of scat detection methods for a social ungulate, the wild pig, and experimental evaluation of factors affecting detection of scat. PLos ONE 11(5): e0155615.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).