Grizzly Bear Noninvasive Genetic Tagging Surveys: Estimating the Magnitude of Missed Detections
| dc.contributor.author | Fisher, Jason T. | |
| dc.contributor.author | Heim, Nicole | |
| dc.contributor.author | Code, Sandra | |
| dc.contributor.author | Paczkowski, John | |
| dc.date.accessioned | 2019-08-19T20:56:23Z | |
| dc.date.available | 2019-08-19T20:56:23Z | |
| dc.date.copyright | 2016 | en_US |
| dc.date.issued | 2016 | |
| dc.description.abstract | Sound wildlife conservation decisions require sound information, and scientists increasingly rely on remotely collected data over large spatial scales, such as noninvasive genetic tagging (NGT). Grizzly bears (Ursus arctos), for example, are difficult to study at population scales except with noninvasive data, and NGT via hair trapping informs management over much of grizzly bears’ range. Considerable statistical effort has gone into estimating sources of heterogeneity, but detection error–arising when a visiting bear fails to leave a hair sample–has not been independently estimated. We used camera traps to survey grizzly bear occurrence at fixed hair traps and multi-method hierarchical occupancy models to estimate the probability that a visiting bear actually leaves a hair sample with viable DNA. We surveyed grizzly bears via hair trapping and camera trapping for 8 monthly surveys at 50 (2012) and 76 (2013) sites in the Rocky Mountains of Alberta, Canada. We used multi-method occupancy models to estimate site occupancy, probability of detection, and conditional occupancy at a hair trap. We tested the prediction that detection error in NGT studies could be induced by temporal variability within season, leading to underestimation of occupancy. NGT via hair trapping consistently underestimated grizzly bear occupancy at a site when compared to camera trapping. At best occupancy was underestimated by 50%; at worst, by 95%. Probability of false absence was reduced through successive surveys, but this mainly accounts for error imparted by movement among repeated surveys, not necessarily missed detections by extant bears. The implications of missed detections and biased occupancy estimates for density estimation–which form the crux of management plans–require consideration. We suggest hair-trap NGT studies should estimate and correct detection error using independent survey methods such as cameras, to ensure the reliability of the data upon which species management and conservation actions are based. | en_US |
| dc.description.reviewstatus | Reviewed | en_US |
| dc.description.scholarlevel | Faculty | en_US |
| dc.description.sponsorship | This work was primarily funded by Alberta Environment and Parks and Alberta Innovates—Technology Futures under the grant title “East Slopes Predators Project.” Scholarship funding was granted to Nicole Heim by Natural Sciences and Engineering Research Council of Canada and Yellowstone to Yukon to Conservation Initiative. Alberta Innovates—Technology Futures provided support in the form of salaries for authors JTF and NH, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Alberta Environment and Parks provided support in the form of salaries for authors SC and JP, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the “author contributions” section. | en_US |
| dc.identifier.citation | Fisher, J.T., Heim, N., Code, S. & Paczkowski (2016). Grizzly Bear Noninvasive Genetic Tagging Surveys: Estimating the Magnitude of Missed Detections PLoS ONE, 11(9), e0161055. https://doi.org/10.1371/journal.pone.0161055 | en_US |
| dc.identifier.uri | https://doi.org/10.1371/journal.pone.0161055 | |
| dc.identifier.uri | http://hdl.handle.net/1828/11043 | |
| dc.language.iso | en | en_US |
| dc.publisher | PLoS ONE | en_US |
| dc.subject.department | School of Environmental Studies | |
| dc.title | Grizzly Bear Noninvasive Genetic Tagging Surveys: Estimating the Magnitude of Missed Detections | en_US |
| dc.type | Article | en_US |