Using Natural Pelt Patterns to Estimate Population Abundance with Mark-Resight Models

摘要: Author(s): Teton, Ben Scott | Advisor(s): Young, Hillary S Abstract: Estimating population abundance through time is an essential component of wildlife conservation and management. However, accurate monitoring can be difficult expensive for many elusive species occurring across large, dynamic landscapes. Thus, managers require methods that accurately estimate abundance, while also minimizing field effort cost. We estimated invasive wild pigs (Sus scrofa) on Tejon Ranch in the Tehachapi Mountains California, using natural markings to identify individuals mark-resight estimation. Wild this region, like not traditionally identified marks, are generally homogeneous appearance with distinctive features range dramatically relative visibility, uniqueness permanence. developed a method based standardized thresholds image quality animal flank distinctiveness account inherent variability between individuals. This was tested over fifteen-month period March 2015 June 2016, array 48 camera traps 48km² survey grid. With 18.5% meeting our conservative standard identifiability, we generated absolute estimates five consecutive three-month sampling periods Poisson log-normal estimator under Pollocks robust design. Using left-flank photos both naturally marked unmarked pigs, ranging from 352 (SE + 56) summer 157 43) spring 2016. These results suggest overall decline pig which supported by simultaneous Ranch-wide hunter harvest totals during period. As requires no trapping or tagging any kind, it may utilized as cost resource efficient alternative traditional techniques rely ear-tags neck-bands individual identification considered unidentifiable marks alone.