Patterns of island fox habitat use in sand dune habitat on San Clemente Island

On San Clemente Island (SCI), the island fox subspecies (Urocyon littoralis clementae) has been monitored annually since 1988 to track long-term population trends. Annual density estimates in most habitat types across the island range from 2–13 foxes/km2, yet unusually high estimates have repeatedly approached 50 foxes/km2 in a unique sand dune habitat area. Although sand dune habitat is restricted to one small area on the island, these estimates suggest sand dune habitat supports one of the highest population densities of any fox species in the world, and it may support > 5% of the SCI fox population. This finding prompted our investigation to determine if SCI foxes captured in the sand dunes habitat area maintained home ranges within this habitat type. Between January–July 2018, we used Global Positioning System collars to track the movements of 12 island foxes captured in the sand dune habitat area. Contrary to our initial predictions, we found that island foxes captured in the sa..., We deployed GPS collars (Advanced Telemetry Systems Model W500) to track the movements of 12 captured island foxes. Each collar weighed 65 g (< 5% of the body weight of a 1.5 kg fox) and was equipped with a VHF transmitter. Collars were programmed to record 1 GPS fix location per hour between 0600–1800 each day for 188 days between January–July 2018. Data were remotely downloaded from all foxes every 7 days using a W100 Com module (Advanced Telemetry Systems) and Yagi antenna from distances up to 400 m.
Home range estimation
We calculated home range sizes from the GPS locations using the ‘adehabitatHR’ package in RStudio (RStudio Team 2022) and ArcMap 10.3 (ESRI 2015). Utilization distributions were generated using the ad hoc method for the estimation of the smoothing parameter (Worton 1989) within ‘adehabitatHR.’ We calculated spatial use metrics including the 95% minimum convex polygon (MCP) home ranges after the removal of 5% of extreme points, 95% fixed kernel density estimate (K..., , # Patterns of island fox habitat use in sand dune habitat on San Clemente Island

[https://doi.org/10.5061/dryad.t1g1jwt9w](https://doi.org/10.5061/dryad.t1g1jwt9w)

We have submitted our raw data and R scripts associated with all home range and resource selection function analyses. The \"DunesHRAnalysis\" R file includes code for estimating Minimum Convex Polygons and Kernel Density Estimates for the 12 island foxes monitored in this study. It requires the csv file \"GPSPoints_ALL_csv,\" which includes all GPS data points for the foxes monitored. The \"RSFAnalysis\" R file includes code for estimating the resource selection functions reported. It requires the csv files \"all_used\" and \"all_rand_kde,\" which includes the vegetation data associated with each used and randomly generated GPS point. 

## Description of the data and file structure

###### **all\_used**

* FoxID: unique identifier for each fox
* East_X: easting for each used data point (Projected Coordinate System: NAD 1983)
* North...