Faculty of Mathematics and Natural Sciences - Biogeography

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Brown bear habitat connectivity in the Carpathians

Connectivity assessments typically assume that animals move preferable in suitable habitat. A new paper by Elżbieta Ziółkowska, just published in Landscape Ecology, shows for bears in the northern Carpathians, that this assumption can be simplistic. Corridors identified based on habitat models and movement models differed substantially, highlighting the value of movement data when assessing connectivity.

Assessing differences in connectivity based on habitat versus movement models for brown bears in the Carpathians

 

Elżbieta Ziółkowska | Katarzyna Ostapowicz | Volker C. Radeloff | Tobias Kuemmerle | Agnieszka Sergiel | Tomasz Zwijacz-Kozica | Filip Zięba | Wojciech Śmietana | Nuria Selva

 

Context - Connectivity assessments typically rely on resistance surfaces derived from habitat models, assuming that higher-quality habitat facilitates movement. This assumption remains largely untested though, and it is unlikely that the same environmental factors determine both animal movements and habitat selection, potentially biasing connectivity assessments.

Objectives - We evaluated how much connectivity assessments differ when based on resistance surfaces from habitat versus movement models. In addition, we tested how sensitive connectivity assessments are with respect to the parameterization of the movement models.

Methods - We parameterized maximum entropy models to predict habitat suitability, and step selection functions to derive movement models for brown bear (Ursus arctos) in the northeastern Carpathians. We compared spatial patterns and distributions of resistance values derived from those models, and locations and characteristics of potential movement corridors.

Results - Brown bears preferred areas with high forest cover, close to forest edges, high topographic complexity, and with low human pressure in both habitat and movement models. However, resistance surfaces derived from the habitat models based on predictors measured at broad and medium scales tended to underestimate connectivity, as they predicted substantially higher resistance values for most of the study area, including corridors.

Conclusions - Our findings highlighted that connectivity assessments should be based on movement information if available, rather than generic habitat models. However, the parameterization of movement models is important, because the type of movement events considered, and the sampling method of environmental covariates can greatly affect connectivity assessments, and hence the predicted corridors.

 

Link to the manuscript: DOI:10.​1007/​s10980-016-0368-8

Citation: Ziółkowska, E., Ostapowicz, K., Radeloff, V. C. Kuemmerle, T.,  Sergiel, A., Zwijacz-Kozica, T., Zieba, F., Śmietana, W.  & Selva, N., (2016): Assessing differences in connectivity assessments for large carnivores based on habitat versus movement models. Landscape Ecology, in press.