Density of American black bears in New Mexico. Issue 4 (20th February 2018)

• Record Type: Journal Article
• Authors: Gould, Matthew J.; Cain, James W.; Roemer, Gary W.; Gould, William R.; Liley, Stewart G.
• Is Part Of: Journal of wildlife management. Volume 82:Issue 4(2018)
• Page Start: 775
• Page End: 788
• Publication Date: 2018-02-20
• Subjects: American black bear -- capture–recapture -- density estimation -- DNA degradation -- New Mexico -- Ursus americanus; Wildlife management -- Periodicals; Zoology -- Periodicals; 333.954
• DOI: 10.1002/jwmg.21432
• Languages: English
• ISSNs: 0022-541X

Abstract

ABSTRACT: Considering advances in noninvasive genetic sampling and spatially explicit capture–recapture (SECR) models, the New Mexico Department of Game and Fish sought to update their density estimates for American black bear ( Ursus americanus ) populations in New Mexico, USA, to aide in setting sustainable harvest limits. We estimated black bear density in the Sangre de Cristo, Sandia, and Sacramento Mountains, New Mexico, 2012–2014. We collected hair samples from black bears using hair traps and bear rubs and used a sex marker and a suite of microsatellite loci to individually genotype hair samples. We then estimated density in a SECR framework using sex, elevation, land cover type, and time to model heterogeneity in detection probability and the spatial scale over which detection probability declines. We sampled the populations using 554 hair traps and 117 bear rubs and collected 4, 083 hair samples. We identified 725 (367 male, 358 female) individuals. Our density estimates varied from 16.5 bears/100 km 2 (95% CI = 11.6–23.5) in the southern Sacramento Mountains to 25.7 bears/100 km 2 (95% CI = 13.2–50.1) in the Sandia Mountains. Overall, detection probability at the activity center (g0) was low across all study areas and ranged from 0.00001 to 0.02. The low values of g0 were primarily a result of half of all hair samples for which genotypes were attempted failing to produce a complete genotype. We speculate that the low success we had genotyping hair samples was due to exceedingly high levels of ultraviolet (UV) radiation that degraded the DNA in the hair. Despite sampling difficulties, we were able to produce density estimates with levels of precision comparable to those estimated for black bears elsewhere in the United States. © 2018 The Wildlife Society. Abstract : We estimated density for American black bear populations in 3 mountain ranges of New Mexico. Updated density estimates (range = 16.6–25.3 bears/100 km 2 ) will aid the New Mexico Department of Game and Fish in setting harvest regulations for American black bears within the sampled Bear Management Zones.