Criterion 1: Conservation of biological diversity - Indicator 6: The number of forest dependent species

Abstract

This indicator monitors the number of native species that are associated with forest habitats. Because one of the more general sign of ecosystem stress is a reduction in the variety of organisms inhabiting a given locale, species counts are often used in assessing ecosystem wellbeing. Data on the distribution of 689 tree and 1,486 terrestrial animal species associated with forest habitats (including 227 mammals, 417 birds, 176 amphibians, 191 reptiles, and 475 butterflies) were analyzed. Species richness (number of species) is highest in the Southeast and in the arid ecoregions of the Southwest. Since the mid-1970s, trends in forest bird richness have been mixed. Ecoregions where forest bird richness has increased the greatest are found in the West and include the Great Basin, northern Rocky Mountains, northern mixed grasslands, and southwestern deserts. Declining forest bird richness has primarily occurred in the East, with notable areas of decline in the Mississippi lowland forests, the southeastern coastal plain, northern New England, southern and eastern Great Lake forests, and central tallgrass prairie. Because monitoring species richness over large geographic areas is logistically difficult, we lack systematic inventories that permit the estimation of species richness over time for most taxonomic groups.

Citation

Flather, Curtis H.; Ricketts, Taylor H.; Sieg, Carolyn Hull; Knowles, Michael S.; Fay, John P.; McNees, Jason. 2003. Criterion 1: Conservation of biological diversity - Indicator 6: The number of forest dependent species. In: Darr, David R., coordinator. Data Report: A Supplement to the National Report on Sustainable Forests -- 2003. FS-766A. Washington, DC: USDA Forest Service, Research & Development. Online: http://www.fs.fed.us/research/sustain/