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FRAGMENTATION OF CONTINENTAL UNITES STATES FORESTS
Citation:
Riitters, K. H., J D. Wickham, R. V. O'Neill, K B. Jones, E R. Smith, J. W. Coulston, T G. Wade, AND J H. Smith. FRAGMENTATION OF CONTINENTAL UNITES STATES FORESTS. ECOSYSTEMS 5(8):815-822, (2003).
Impact/Purpose:
The objective of this task is to produce land-cover and related products that are needed to meet Annual Performance Goals (APG) under GPRA Goals Clean Air, Clean Water, and Healthy and Safe Communities, and to meet the critical needs of EPA Regional Offices.
Description:
We report a multiple-scale analysis of forest fragmentation based on 30-m land-cover maps for the conterminous United States. Each 0.09-ha unit of forest was classified according to fragmentation indices measured within the surrounding landscape, for five landscape sizes from 2.25 ha to 5314.41 ha. Most forest resided in fragmented landscapes. With 65.61-ha landscapes, for example, only 9.9 % of all forest was contained in a fully forested landscape, and only 46.9% was in a landscape that was more than 90% forested. Forest edge was located with 90 m of 43.5% of all forest, and within 150 m of 61.8% of all forest. Nevertheless, where forest existed it usually was dominant - 72.9% of all forest was in landscapes that were at least 60% forested for landscapes up to 5314.41 ha. Small (<7.29 ha) perforations in otherwise continuous forest cover accounted for about half of the fragmentation. These results suggest that forests are more or less connected over large regions, but also that fragmentation is so pervasive that edge effects potentially influence ecological processes over most forested lands.