Predicted connectivity pathways for grizzly bears between the Selkirk and Cabinet-Yaak Ecosystems: spatial data

Publication Date

2024-05-15

Start Date

2003-05-01

End Date

2023-06-01

Sells, S.N., and Costello, C.M., 2023, Grizzly Bear Space Use in the US Northern Rocky Mountains (ver. 3.0, July 2024): U.S. Geological Survey data release, https://doi.org/10.5066/P91EWUO8.

Grizzly bear populations in the continental US are fragmented and connectivity among federal recovery areas is a conservation goal. Our objective was to identify potential connectivity pathways for grizzly bears between the Selkirk (SE) and Cabinet-Yaak (CYE) Ecosystems. To achieve this objective, we built on a larger study initiated in Sells et al. (2022). In this first phase, the authors developed integrated step selection functions (iSSFs) within the NCDE to better understand how grizzly bears use habitat. Subsequent application of these models to the NCDE demonstrated high predictive power. In a second phase, Sells et al. (2023a) demonstrated that models developed for the NCDE accurately predicted habitat use in nearby populations and were therefore expected to be transferable and reliable for predicting space use beyond the NCDE. In a third phase, Sells et al. (2023b) demonstrated that multiple simulation methods help predict connectivity pathways and where to focus conservation efforts. As Sells et al. (2023b) excluded the SE-CYE routes in favor of predicting movements between the CYE, NCDE, BE, and GYE, we present predictions between the SE and CYE here. iSSFs extend traditional step selection functions to mechanistically model movement. Randomized shortest paths then enable using the iSSFs to simulate varying degrees of optimal versus exploratory movements between a given start and end node. We employed iSSFs to model randomized shortest paths between the SE and CYE. We used Sells et al. (2022)’s iSSFs, built using movement data from 65 GPS-collared grizzly bears (46 females and 19 males) monitored during 2003 – 2020 in the NCDE. Data used in the models were from the primary active season of May through November. Sells et al. (2022)’s iSSFs represented hypotheses that landscape features influencing grizzly bear habitat selection include food availability, terrain ruggedness, forested areas, forest edges, riparian areas, building densities, and distance to secure (unroaded) habitat. Because Sells et al. (2022)'s iSSFs demonstrated high individual variation in spatial behavior, our connectivity simulations were likewise individual based to account for variations in movement behaviors.

• Cooperative Fish and Wildlife Research Units

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