干旱区生态环境知识资源中心

We collected fecal samples (scats) of sympatric bobcats (Lynx rufus) and coyotes (Canis latrans) between 2000 and 2003 in a 53,600-ha area of the Upper Sonoran Desert in central Arizona. Our objective was to investigate composition, diversity, and overlap of diets of bobcats and coyotes in relation to varying rainfall in the Sonoran Desert of central Arizona. In general, bobcats ate more rodents than did coyotes, and coyotes ate more lagomorphs, large prey, and fruit/seeds than did bobcats. Composition of bobcat diets was independent of differences among years in annual rainfall and seasonal rainfall during summer-autumn (May-October) and winter-spring (November-April). Composition of coyote diets also was independent of drought conditions among years during summer-autumn, but coyotes ate more large prey and fewer rodents during years with winter-spring drought. Seasonally, bobcats ate more rodents than did coyotes in summer-autumn and winter-spring, whereas coyotes ate more lagomorphs than did bobcats during winter-spring, and more large prey and fruit/seeds in both seasons. Coyotes ate more large prey and lagomorphs during winter-spring, when seasonal rainfall was higher, and more fruit/seeds in summer-autumn, when seasonal rainfall was lower. Diversity of diets was consistently higher for coyotes than for bobcats, and increased for bobcats but not for coyotes during winter-spring drought and during higher seasonal rainfall in winter-spring. Overlap of diets between predators was independent of rainfall levels. We suggest that bobcats in the Sonoran Desert are more selective, specialized predators and that coyotes are more generalist, opportunistic predators. We hypothesize that, although diversity of bobcat food items and composition of coyote diets differ with varying rainfall in the Sonoran Desert, patterns of feeding strategy are independent of seasonal differences in precipitation and effects of drought, and bobcats and coyotes partition food resources independently of varying rainfall.