Mojave desert tortoise (Gopherus agassizii) thermal ecology and reproductive success along a rainfall cline

摘要: Desert resource environments (e.g. microclimates, food) are tied to limited, highly localized rainfall regimes which generate microgeographic variation in the life histories of inhabitants. Typically, enhanced growth rates, reproduction and survivorship observed response increased availability a variety desert plants short-lived animals. We examined thermal ecology US federally threatened Mojave tortoises (Gopherus agassizii), long-lived large-bodied ectotherms, at opposite ends 250-m elevation-related cline within Ivanpah Valley eastern Desert, California, USA. Biophysical operative both upper-elevation, "Cima," lower-elevation, "Pumphouse," plots corresponded with daily seasonal patterns incident solar radiation. Cima received 22% more contained greater perennial vegetative cover, conferred 5°C-cooler daytime shaded temperatures. In monitored average year, had longer potential activity periods by up several hours ephemeral forage. Enhanced was associated larger-bodied females producing larger eggs, while still same number eggs as Pumphouse females. However, reproductive success lower because 90% were depredated versus 11% Pumphouse, indicating that predatory interactions produced counter-gradient across cline. Land-use impacts on deserts energy generation) increasing rapidly, conservation strategies designed protect recover inhabitants, such tortoises, should incorporate these strong ecosystem-level responses regional assessments habitat for prospective development mitigation efforts.