Oral Session - Quantitative Relationships Between Landscape Processes and Patterns and Wildlife - Morning Session Chair(s): Robinson, Vincent¹, ¹ University of Toronto at Mississauga, Mississauga, ON, Canada
Friday, April 2, 2004 9:00 AM - 11:00 AM Apollo Room 1-2

Species richness, multi-temporal NDVI, and habitat transformation: an analysis using South African birds. Fairbanks, Dean^*,1, ¹ Department of Geography and Planning, Chico, CA, USA

ABSTRACT- Energy, habitat heterogeneity, and habitat transformation are important correlates of spatial variation in species richness, however few investigations have simultaneously sought to determine their relative influences as determined by remote sensing. South African avifauna was used to examine the degree to which species richness is related to these variables under biologically meaningful analysis extents. AVHRR NDVI data used covers the same time frame as the avifauna dataset. Principal Components Analysis (PCA) reduced the AVHRR data to two variables representing the sum and temporal trajectories of mean NDVI across South Africa. Two other variables representing heterogeneity were developed from the standard deviation of the NDVI. Taking spatial autocorrelation into account it was found that the first PCA, precipitation, absolute minimum temperature, high intensity transformation, and first PCA heterogeneity account for the most of the variation in species richness in the summer rainfall zone. In contrast, potential evapotranspiration (PET), second PCA, absolute maximum temperature, high intensity transformation, and second PCA heterogeneity account for the most variation in species richness in the winter rainfall zone. Species richness and NDVI based productivity are positively related in the summer zone, while unimodal in the winter zone along with PET. The findings indicate that avifauna species richness is correlated with, and hence likely a function of, water-energy dynamics which can be measured using NDVI, absolute temperatures, and to a lesser degree heterogeneity. Furthermore, habitat transformation, which has a positive relationship with species richness, and spatial extent must be taken into account during investigations of these relationships.

KEY WORDS: heterogeneity, energy availability, habitat transformation, normalized difference vegetation index NDVI, potential evapotranspiration