Integrating opportunistic and structured non-invasive surveys with spatial capture-recapture models to map connectivity of the Pyrenean brown bear population
Résumé
Connectivity, in the sense of the persistence of movements between habitat patches, is key to maintain endangered
populations and has to be evaluated in management plans. In practice, connectivity is difficult to quantify
especially for rare and elusive species. Here, we use spatial capture-recapture (SCR) models with an ecological
detection distance to identify barriers to movement. We focused on the transnational critically endangered
Pyrenean brown bear (Ursus arctos) population, which is distributed over Spain, France and Andorra and is
divided into two main cores areas following translocations. We integrate structured monitoring from camera
traps and hair snags with opportunistic data gathered after depredation events. While structured monitoring
focuses on areas of regular bear presence, the integration of opportunistic data allows us to obtain information in
a wider range of habitat, which is especially important for ecological inference. By estimating a resistance
parameter from encounter data, we show that the road network impedes movements, leading to smaller home
ranges with increasing road density. Although the quantitative effect of roads is context-dependent (i.e. varying
according to landscape configuration), our model predicts that a brown bear with a home range located in an
area with relatively high road density (8.29 km/km2) has a home range size reduced by 1.4-fold for males and
1.6-fold for females compared to a brown bear with a home range located in an area with low road density (1.38
km/km2). When assessing connectivity, spatial capture-recapture modeling offers an alternative to the use of
experts’ opinion when telemetry data are not available.
Origine | Fichiers éditeurs autorisés sur une archive ouverte |
---|