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    Author(s): Mark J. Jordan; Reginald H. Barrett; Kathryn L. Purcell
    Date: 2011
    Source: Wildlife Biology 17:266-276
    Publication Series: Scientific Journal (JRNL)
    Station: Pacific Southwest Research Station
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    Developing efficient monitoring strategies for species of conservation concern is critical to ensuring their persistence. We have developed a method using camera traps to estimate density and survival in mesocarnivores and tested it on a population of fishers Martes pennanti in an area of approximately 300 km2 of the southern Sierra Nevada mountains in California. Fishers in this region are isolated from other populations by a gap of approximately 400 km, and the status of individual populations in the southern Sierra Nevada is poorly understood, making management decisions difficult. We caught fishers in live traps, marked them with ear tags, and resighted them with camera traps. We measured latency to first detection and detection rate to compare our results to previous camera trapping studies of fishers. We used the robust design Poisson log-normal mixedeffects mark-resight model to obtain annual estimates of density and apparent survival. Our values for latency to first detection and detection rate were slightly lower than those obtained by previous studies. Fishers in this isolated region occur at lower densities than at other locations across their range with only approximately 6-11 animals/100 km2. Their average annual, adult survival rate (0.94) was comparable to that found in other studies, though this parameter had very low precision. We experienced relatively high levels of tag loss in our study, suggesting our estimates of abundance are biased upward. We provide recommendations for improving the precision and accuracy of results obtained from this type of study. Our results demonstrate a novel application of mark-resight methods to estimate density and survival for mesocarnivores. These estimates provide timely information to managers about fishers at the local population level in the southern Sierra Nevada mountains.

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    Jordan, Mark J.; Barrett, Reginald H.; Purcell, Kathryn L. 2011. Camera trapping estimates of density and survival of fishers (Martes pennanti). Wildlife Biology 17:266-276.


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    camera trapping, density estimation, mark-resight, Martes pennanti, mesocarnivore, Sierra Nevada, survival rate estimation

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