I am interested in the dynamics of populations, communities and ecosystems. I use experimental and modeling approaches to investigate plant resource use and plant interactions in a variable and changing environment. Research on the fundamentals of plant function and population growth is relevant to many applied problems in ecology, such as the management of ecosystems in times of rapid climate change, or the control of invasive species.

The Colorado Plateau is a cold desert with about as much precipitation in fall/winter as in spring/summer. Near Moab, Utah, average annual precipitation is 215 mm, but year-to-year variation is high.....more

Most people think of deserts as very dry places. In reality, deserts are highly variable and unpredictable....more

The stability of grazing systems.

Grazing systems can be intrinsically unstable. This means that excessive harvesting can lead to sustained productivity losses...more

One of the prominent features of natural and managed plant populations is that their members are often highly variable in size. Many physiological and morphological properties of individuals depend on plant size...more