Spatial Scales and Global Change: Bridging the Gap from Plots to GCM Grid Cells

The complexity of earth system processes results from interactions among the physical, chemical, and biological subsystems that vary in both time and space. Gaining an understanding of these dynamics has taken on great importance in the context of current environmental change and the portent of even larger scale global change. Appreciation for the concept of "scaling" is increasing as we are challenged to integrate data and models from different disciplines and different time and space scales. In particular, biophysical and ecological information, intrinsically derived at the scale of the individual organism, must be extrapolated to the regional and global scales of climate models. Unfortunately, this may not always be a simple process due to complex spatial variations and nonlinearities in dynamics across landscapes. Bridging the gap between our site-level ecological understanding and global scale phenomena challenges our current disciplinary approach and requires new strategies for acquiring and interpreting information on large-scale earth system dynamics. Research tools such as remote sensing and simulation modeling hold the potential for clarifying general ecological principles by expanding limitations inherent in site-level studies (81, 125). In combination, technologies of remote sensing, geographic information systems, and simulation modeling permit quantitative assessment of the consequences of heterogeneity in earth systems over a broad range of spatial and temporal scales. Remote sensing techniques extend measurements to scales over which biospheric processes operate and