Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method
Camera-traps are increasingly used to estimate wildlife abundance, yet few studies exist for small-sized carnivores or comparing efficacy against traditional methods. We developed a camera-trap to identify the unique ventral patches of American martens (Martes americana). Our method was designed to:...
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MDPI AG
2016-01-01
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| Online Access: | http://www.mdpi.com/1424-2818/8/1/3 |
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| author | Alexej P. K. Sirén Peter J. Pekins Peter L. Abdu Mark J. Ducey |
| author_facet | Alexej P. K. Sirén Peter J. Pekins Peter L. Abdu Mark J. Ducey |
| author_sort | Alexej P. K. Sirén |
| collection | DOAJ |
| description | Camera-traps are increasingly used to estimate wildlife abundance, yet few studies exist for small-sized carnivores or comparing efficacy against traditional methods. We developed a camera-trap to identify the unique ventral patches of American martens (Martes americana). Our method was designed to: (1) determine the optimal trap configuration to photograph ventral patches; (2) evaluate the use of temporally clustered photographs to determine independence and improve identification; and (3) determine factors that influence identification probability. We tested our method by comparing camera- and live-trap density estimates using spatial capture–recapture (SCR) models. The ventral patches of radio-collared martens were most visible when traps were placed 15–20 cm above a feeding platform. Radio-collared martens (n = 14) visited camera-traps for long periods (median = 7 min) with long intervals between visits (median = 419 min), and visits by different martens at the same trap <15 min apart was infrequent (n = 3) during both years. Similarly, there was complete agreement among observers that clustered photos of un-collared martens were always of the same individual. Pairwise agreement was high between observers; eight un-collared martens were identifiable by consensus on 90% (54 of 60) of recorded visits. Factors influencing identification probability were directly related to the time martens spent feeding at traps (β = 0.143, P = 0.01) and inversely proportional to the time that elapsed since traps were baited (β = −0.344, P = 0.006). Density estimates were higher and more precise for camera-trapping (0.60, 0.35–1.01 martens/km2) than live-trapping (0.45, 0.16–1.22 martens/km2), providing evidence that SCR density estimates may be biased when capture heterogeneity is present, yet cannot be accounted for due to small sample size. Our camera-trap method provides a minimally invasive and accurate tool for monitoring marten populations. |
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| institution | Directory Open Access Journal |
| issn | 1424-2818 |
| language | English |
| last_indexed | 2024-04-13T06:42:21Z |
| publishDate | 2016-01-01 |
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| series | Diversity |
| spelling | doaj.art-afdaba40e21047dbbf3b4323a8da1f2d2022-12-22T02:57:42ZengMDPI AGDiversity1424-28182016-01-0181310.3390/d8010003d8010003Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap MethodAlexej P. K. Sirén0Peter J. Pekins1Peter L. Abdu2Mark J. Ducey3Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USADepartment of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USADepartment of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USADepartment of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USACamera-traps are increasingly used to estimate wildlife abundance, yet few studies exist for small-sized carnivores or comparing efficacy against traditional methods. We developed a camera-trap to identify the unique ventral patches of American martens (Martes americana). Our method was designed to: (1) determine the optimal trap configuration to photograph ventral patches; (2) evaluate the use of temporally clustered photographs to determine independence and improve identification; and (3) determine factors that influence identification probability. We tested our method by comparing camera- and live-trap density estimates using spatial capture–recapture (SCR) models. The ventral patches of radio-collared martens were most visible when traps were placed 15–20 cm above a feeding platform. Radio-collared martens (n = 14) visited camera-traps for long periods (median = 7 min) with long intervals between visits (median = 419 min), and visits by different martens at the same trap <15 min apart was infrequent (n = 3) during both years. Similarly, there was complete agreement among observers that clustered photos of un-collared martens were always of the same individual. Pairwise agreement was high between observers; eight un-collared martens were identifiable by consensus on 90% (54 of 60) of recorded visits. Factors influencing identification probability were directly related to the time martens spent feeding at traps (β = 0.143, P = 0.01) and inversely proportional to the time that elapsed since traps were baited (β = −0.344, P = 0.006). Density estimates were higher and more precise for camera-trapping (0.60, 0.35–1.01 martens/km2) than live-trapping (0.45, 0.16–1.22 martens/km2), providing evidence that SCR density estimates may be biased when capture heterogeneity is present, yet cannot be accounted for due to small sample size. Our camera-trap method provides a minimally invasive and accurate tool for monitoring marten populations.http://www.mdpi.com/1424-2818/8/1/3camera trapsAmerican martenspatial capture–recapturewildlife survey methodologyidentification probability |
| spellingShingle | Alexej P. K. Sirén Peter J. Pekins Peter L. Abdu Mark J. Ducey Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method Diversity camera traps American marten spatial capture–recapture wildlife survey methodology identification probability |
| title | Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method |
| title_full | Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method |
| title_fullStr | Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method |
| title_full_unstemmed | Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method |
| title_short | Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method |
| title_sort | identification and density estimation of american martens martes americana using a novel camera trap method |
| topic | camera traps American marten spatial capture–recapture wildlife survey methodology identification probability |
| url | http://www.mdpi.com/1424-2818/8/1/3 |
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