Terrestrial ecosystem ecology and response to environmental change

The research program described here targets improved understanding of the interactions between vegetation, soils, the atmosphere, and other living organisms in terrestrial ecosystems, with the goal of understanding basic controls over ecosystem functions. It is critical to understand these interactions in an integrated ecosystem context in order to understand basic ecological processes, as well as to allow forecasting of ecosystem response to change. Arid and semi-arid ecosystems have historically been subject to a range of human impacts, including resource extraction, domestic animal grazing/browsing, changes in fire regimes, and direct alteration of vegetation structure and the water cycle (Holecheck et al. 1989, Satterlund and Adams 1992, Shugart 1998). These impacts continue at local to regional scales with varying intensities and spatial distributions. In addition, larger-scale changes in atmospheric chemistry (e.g., elevated atmospheric CO2 concentrations and nitrogen pollution) and climate (e.g., increased drought) promise to interact with these smaller scale dynamics to result in currently poorly-forecasted alterations of such important ecosystem functions as water, carbon, and nitrogen cycling (e.g., Campbell and Stafford Smith 2000). It is precisely these functions on which a range of human activity depends and so it is critical to understand them if rational management approaches are to be continued and improved.

Terrestrial ecosystem ecology and response to environmental change Grant