Current Projects

Linking precipitation and primary productivity to carbon resource flux in a Chihuahuan Desert Food web. As part of my dissertation research I have been using stable isotope methodology to examine the importance of C3 and C4 plants as energy and nutrient sources for a Chihuahuan Desert arthropod and lizard community at the Sevilleta Long Term Ecological Research (LTER) site.

Effects of productivity and nutrient availability in C3 and C4 plants on the abundance, size and macronutrient composition of arthropods. Controlled experiments have shown that the differing nutrient qualities of C3 and C4 plants dramamtically impact the growth rate, adult size and nutrient composition of grasshoppers.Using stable isotopes and compositional analysis, this study will be the first field based test examining the impacts that plant nutrient quality may have on herbivorous consumers.

Prey quality effects on the allocation strategies to reproduction in a lizard: Stable isotope analysis of capital vs. income breeding. I am manipulating the fat store and dietary carbon isotope values of prairie lizards (Sceloporus undulatus consubrinus) to examine how dietary quality may impact the degree to which stored resources are utilized for egg development. Through carbon isotope analysis of body and egg tissues I am quantifying the sources (stored vs. dietary) used to provision eggs. Also with an ultrasound imaging device I am tracking the rate at which eggs are developed.

Nutrient dynamics in a desert food web: Linking nutrient availability to the allocation strategies of a lizard community. This project is a culmination of the above studies, in which I am using natural seasonal variation in the carbon isotope values of lizard fat stores and diet to examine capital vs. income breeding across a number of lizard species.

Reproductive effort and the clutch size/offspring size trade-off in lizards. This work is in collaboration with Dr. E.L. Charnov and Dr. Melanie Moses. In two recently submitted manuscripts we use our compiled lizard dataset to test predictions from life history theory. We test predictions regarding lifetime reproductive effort, reproductive allometry and the impact of resource allocation on the clutch size/offspring size trade-off in lizards.

The importance of columnar cacti as energy and water sources for a Sonoran Desert arthropod and bird community. As a research assistant to my PhD advisor, Blair O. Wolf, I helped to net, band and bleed close to 3000 birds in Organ Pipe National Monument, AZ. In this work we use stable isotopes to investigate the seasonal importance of saguaro and organ pipe cacti to arthropods and birds.

Research Grants and Fellowships