I am a desert ecologist, with an emphasis on the spatial distribution and physiological ecology of desert reptiles. Most of my research is focused in and around the Mojave desert, but work with other colleagues has lured me into the Sonoran Desert of Southern Arizona, and a wide variety of habitats in Baja California.

I am generally interested in the physiological ecology desert organisms, especially desert reptiles and notably desert tortoises (Gopherus agassizii). In particular, I am interested in how the interactions of environmental and physiological constraints define the ecology and distribution of these animals. Because of the severe conditions and low resources associated with the desert environment, selective pressures tend to produce interesting adaptations. Many factors may be acting simultaneously to influence the natural distributions of these animals. Environmental factors may include: the biophysical environment, elevational limitations, local precipitation, forage availability, the composition of the substratum.

Additionally, factors influencing the biology of the animal may limit their distributions including: the range of acceptable temperatures (and other tolerance related attributes of the animal), the thermoregulatory behavior of the species, the locomotory ability of the species at each stage of its existence, shelter requirements, nutritional requirements, etc. This may create limitations when the animal is further constrained within a limited range of existing available habitat.

The results of this interaction may be expressed by a reduction of available habitat to habitat that can actually be used by the animals. This distinction may be critical when constructing conservation schemes for rare and endangered species. Allocation of habitat may be of no benefit if it is not within the parameters set by the combination of the tolerances of the animal and its interaction with the environment. A basic understanding of each of these may help to better assess useable habitat which can be applied to conservation strategies.

I’m conducting habitat modeling for a variety of species with a focus on understanding the ecological relationships that define and limit plant and animal distributions and development of GIS layers that accurately reflect those dependencies and limitations. I currently work with a variety of collaborators within UNR, UC Davis, Penn State, Arizona State and the University of Arizona, and scientists from the USGS. I am always looking collaborators working on interesting questions, please feel free to contact me!