Scale-dependent Relationships between Population and Environment in Northeastern Thailand

Social and biophysical data were collected, integrated, and analyzed to examine scale-dependent relationships between selected population and environmental variables for a study site in northeast Thailand. Data sets were genemted through the. use of remote sensing to characterize land-use/land-cover and plant biomass variation across the Nang Rong district; GIS to derive elevation, slope angle, and soil moisture potential; social survey data at the village level to categorize demographic variables; and a population distribution model to transform demographic data collected at discrete village locations to spatially continuous surfaces stratified by agricultural land uses. Statistical analysis employed multiple regression to estimate population density in relation to social and biophysical variables, and canonical analysis to relate population variables to environmental variables across a range of spatial scales extending from 30 to 1050 m. Findings indicate the importance of spatial scale in the study of population and the environment. Regression models reflect the scale dependence of the selected variables through plots of slope coefficients and R2 values across nine scale steps. The variation in relationships among environment and population variables, evidenced through factor loadings associated with canonical correlation, suggest that relationships are not genemlizeable across the sampled spatial scales. Introduction Fundamental to landscape ecology is the explicit interrelationship of scale, pattern, and process, and the realization that landscape form and function are linked through theory and practice. Implicit is the interaction of biophysical and social processes through a set of complex interrelationships that are composited and define spatial pattern across temporal andlor spatial scales. The landscape matrix reflects this imprint of human and environmental processes, feedback mechanisms between them, and the geographic site and situation of the landscape as viewed across space and time. While prior research (e.g., Quattrochi and Goodchild, 1997) has sought to explore spatial patterns extending across a range of spatial scales associated with biophysical processes and "natural" landscapes, sufficient attention has not been paid to the importance of biophysical processes linked S.J. Walsh and W.F. Welsh are with the Department of Geography, University of North Carolina, Chapel Hill, NC 27599-