Meeting Abstract
The among-year variation in means and extremes of rainfall and precipitation of deserts ecosystems are expected to cause predictable, among-year responses in production through several trophic levels of desert ectotherms. How ectotherm consumers compare in the variation of production responses is not readily apparent, however, because species of ectotherms vary considerably in a) modes of food acquisition, b) prey types, c) activity patterns, d) predation threat, e) daily patterns of body temperature, and e) life-history traits. Thus, given annual variation in climate and prey availability in the northern Great Basin desert, a bewildering plethora of alternative and contrasting assumptions and associated predictions can be made for the outcomes of production in trophically contrasting lizard species. A first approach to this multivariate conundrum was a decade-long observational-descriptive-comparative study of lizards from three genera: 1) the western whiptail lizard, Aspidoscelis tigris, which eats many caterpillars in late spring and other prey such as termites in summer, 2) the desert horned lizard, Phrynosoma platyrhinos, primarily a specialist on ants and 3) the long-nosed leopard lizard, Gambelia wislizenii, which preys mostly on grasshoppers and lizards. The annual patterns of body condition and fecal production—as measures of foraging success—and the following-year patterns of juvenile recruitment into the populations of these three species were measured, and then these response variables were examined with respect to among-year variation in availability of prey and climate. There were some of the expected correlates of climate with prey and predator productivity, but variation in responses among the three lizard species suggests intrinsic features unique to each species.
