Areas of significant topographic relief often form ecoclines, resulting in stratified life zones each with distinct communities of plants and animals (Attrill and Rundle 2002). Contact zones, or ecological boundaries along ecoclines, allow unique plant and animal assemblages that are not normally considered to be syntopic, to mix in varying degrees. The boundaries of ecoclines are thus both spatial and ecological and when these boundaries are crossed unique interactions can occur, including unexpected predator and prey interactions.
The eastern San Bernardino Mountains in southern California range from about 300– 3,506 m and support a wide range of as many as 11 distinct life zones along an ecocline extending from Sonoran Desert on the east side and Mojave Desert on the north side, to an alpine ecosystem near the summit (Schoenherr 1992). In this paper we report an interaction between black bears ( Ursus americanus ) and Agassiz’s desert tortoises (Gopherus agassizii). These two species have not previously been reported to interact due to their substantially different habitat preferences. In addition, given the paucity of bear and turtle interactions in general, we provide a review of the scientific literature on the topic, since bears are known to eat turtles on an opportunistic basis.
The study site is located in the foothills of the southeastern San Bernardino Mountains in Riverside County, California, near the city of Palm Springs (33º 57' 06' N, 116º 40' 02" W, WGS84). Known locally as ‘‘Mesa,’’ the site is located on land administered by the Bureau of Land Management for wind energy generation since 1983. Extensive studies of G. agasszii have been conducted at the site since 1994, including investigations on growth, demography and survivorship (Lovich et al. 2011b), fire ecology (Lovich et al. 2011c), habitat selection (Lovich and Daniels 2000), the effects of climate on behavior and reproductive ecology (Ennen et al. 2012b; Lovich et al. 2012; Lovich et al. 1999), nesting ecology (Ennen et al. 2012a) and the impacts of wind energy operation and maintenance on tortoises (Lovich and Ennen 2013; Lovich et al. 2011a).