Effect of anthropogenically developed areas on spatial distribution of island foxes.

Virtually no information exists on the impacts of urban areas on island endemics. We examined the spatial distribution of island foxes (Urocyon littoralis clementae) associated with 3 small anthropogenically developed (i.e., "urban") areas and nonurban areas on San Clemente Island, California. Annual home range size averaged 0.84 km² (n = 25, SE = 0.07). Our top model indicated that foxes that spent a greater proportion of time in urban areas had significantly smaller home ranges (βPUrb = -0.009, 95% confidence interval [CI] =-0.0180-0.0002). We found no effect of sex (βSex = 0.0135, 95% CI = -0.1430-0.1700), age (βAge = 0.0502, 95% CI = -0.2730-0.3734), or whether or not a fox was considered a "road" fox (βRoad = -0.0063, 95% CI = -0.2638-0.2513) on home range size. We noted considerable overlap of home ranges of foxes that used urban areas. Foxes used urban areas a greater proportion of time during the night than during the day (t24 = -6.13, P < 0.001); however, foxes did not spend a greater proportion of time in urban areas than expected overall (t24=-0.59, P = 0.560). We observed 13 of 25 (52%) foxes that utilized urban areas feeding on anthropogenic food resources. Foxes that used urban areas were heavier (n = 35, ̄X = 1.98, SE = 0.05) than foxes that did not use urban areas (n = 26, ̄X = 1.81, SE = 0.04; t59 = -2.69, P = 0.009). Our study is the first to demonstrate the effects urban areas on islands may have on canid populations. our findings were similar to those reported for urban canid populations on the mainland, suggesting that future conservation and management of carnivores on islands may benefit from strategies that have been successful with mainland species. [ABSTRACT FROM AUTHOR]