DIVERSITY OF ECOLOGICAL COMMUNITIES OF THE UNITED-STATES

Biodiversity, although recognized as encompassing several levels of bi ological organization, is often thought of as species diversity Three diversity estimates were calculated for the conterminous United States using satellite data acquired from the Advanced Very High Resolution Radiometer (AVHRR): land cover richness, vegetation richness, and vege tation clustering. Vegetation richness and vegetation clustering showe d a scare-dependent relationship to elevation across the range of quad rat sizes from 500 to 50,000 mi(2). All diversity measures increased e ast to west, with a rather abrupt transition at the Colorado Front Ran ge. The longitudinal diversity gradients found in this study are in co ntrast to the reported latitudinal and longitudinal gradients for spec ies diversity.