Mark-Recapture and Mark-Resight Methods for Estimating Abundance with Remote Cameras: A Carnivore Case Study

• DOI: 10.1371/journal.pone.0123032
• Publication Date: 2015-03-31T07:31:18Z
• Authors: Robert S. Alonso; Brett T. McClintock; Lisa M. Lyren; Erin E. Boydston; Kevin R. Crooks
• Keywords: Mark and recapture; Carnivore; Abundance estimation; Camera trap

Abundance estimation of carnivore populations is difficult and has prompted the use non-invasive detection methods, such as remotely-triggered cameras, to collect data. To analyze photo data, studies focusing on carnivores with unique pelage patterns have utilized a mark-recapture framework without used mark-resight framework. We compared methods estimate bobcat (Lynx rufus) population sizes, which motivated development new "hybrid" model an alternative traditional methods. deployed sampling grid 30 cameras throughout urban southern California study area. Additionally, we physically captured marked subset GPS telemetry collars. Since could identify individual bobcats photos was marked, were able well developed abundance. recorded 109 during 4,669 camera nights 27 estimates produced by mark-recapture, mark-resight, similar, however precision differed depending models used. Traditional relatively imprecise percent confidence interval lengths exceeding 100% point estimates. Hybrid better intervals not 57%. The increased hybrid method stems from utilizing complete encounter histories individuals (including those never detected trap) naturally at traps. This estimator may be particularly useful for estimating abundance uniquely identifiable species that are sample using traps alone.