Spatial and temporal dynamics of vegetation in the San Pedro River basin area

Changes in climate and land management practices in the San Pedro River bas in have altered the vegetation patterns and dynamics. Therefore, there is a need to map the spatial and temporal distribution of the vegetation commun ity in order to understand how climate and human activities affect the ecos ystem in the arid and semi-arid region. Remote sensing provides a means to derive vegetation properties such as fractional green vegetation cover (f(c )) and green leaf area index (GLAI). However, to map such vegetation proper ties using multitemporal remote sensing imagery requires ancillary data for atmospheric corrections that are often not available. In this study, we de veloped a new approach to circumvent atmospheric effects in deriving spatia l and temporal distributions off, and GLAI. The proposed approach employed a concept, analogous to the pseudoinvariant object method that uses objects void of vegetation as a baseline to adjust multitemporal images. Imagery a cquired with Landsat TM, SPOT 4 VEGETATION, and aircraft based sensors was used in this study to map the spatial and temporal distribution of fraction al green vegetation cover and GLAI of the San Pedro River riparian corridor and southwest United States. The results suggest that remote sensing image ry can provide a reasonable estimate of vegetation dynamics using multitemp oral remote sensing imagery without atmospheric corrections. (C) 2000 Elsev ier Science B.V. All rights reserved.