Current theories regarding colonization of South America by mammals are divided between those supported by fossil evidence, which suggest the original mammal fauna of the isolated continent was augmented by early immigrants (primates, caviomorph rodents, and later, procyonids) with a final large influx of northern mammals occurring with the formation of the Panama land bridge, and an opposing v...

Truffles ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy) or from soil organic matter (saprotrophy). The objective of this work was to investigate the heterotrophic side of the ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and ascocarps. In 2010, a single hazel tree selecte...

The ability of a fungus to infect novel hosts is dependent on changes in gene content, expression, or regulation. Examining gene expression under simulated host conditions can explore which genes may contribute to host jumping. Insect pathogenesis is the inferred ancestral character state for species of Tolypocladium, however several species are parasites of truffles, including Tolypocladium op...

The high temperatures and extended droughts that characterize habitat for desert-living reptiles may already approach their physiological tolerances and so could put them at risk due to climate change. Here I examined climate change sensitivity for desert tortoises, Gopherus agassizii, and common chuckwallas, Sauromalus ater, two large-bodied reptiles that occur across the MojaveeSonoran Desert...

– In the Colorado Desert of California, the western distributional limit of the desert tortoise (Gopherus agassizii) occurs in the Whitewater Hills of the southeastern San Bernardino Mountains. Much of the area has been developed for wind energy generation and tortoises often live in association with altered industrial landscapes. Natural habitat in the area was characterized by a sharp transit...

BACKGROUND Ambient particulate matter (PM) has an adverse effect on respiratory morbidity. Desert dust outbreaks contribute to increased PM levels but the toxicity of desert dust mixed with anthropogenic pollutants needs clarification. METHODS We identified 132 days with desert dust episodes and 177 matched days by day of the week, season, temperature and humidity between 2001 and 2006 in Ath...

Ongoing cti sruption of ancient , varnished desert pave ment surfaces ncar Death Valley Nat ional Park is inferred to be the result of unusually intense animal foraging activity. lncreased levels of biotllrbation are associated with enhanced vegetation growth stimulated by recen t EI Nino precipitation. The occurrence of abundant, recen tly overturned, varnished clasts suggests that the pavemen...

Current global changes are putting both biodiversity and the processes that depend on it at risk. This is especially true for semi-arid regions and the flagship groups that inhabit them, such as amphibians and reptiles. Semi-arid regions are often thought to have lower biodiversity and thus have been overlooked, resulting in the underestimation of their biological richness. Therefore, the aim o...

Desert dust perturbs climate by directly and indirectly interacting with incoming solar and outgoing long wave radiation, thereby changing precipitation and temperature, in addition to modifying ocean and land biogeochemistry. While we know that desert dust is sensitive to perturbations in climate and human land use, previous studies have been unable to determine whether humans were increasing ...