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EVALUATING ECOREGIONS FOR SAMPLING AND MAPPING LAND-COVER PATTERNS
Citation:
RIITTERS, K. H., J. D. WICKHAM, AND T. G. WADE. EVALUATING ECOREGIONS FOR SAMPLING AND MAPPING LAND-COVER PATTERNS. PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING 72(7):781-788, (2006).
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:
Ecoregional stratification has been proposed for sampling and mapping land- cover composition and pattern over time. Using a wall-to-wall land-cover map of the United States, we evaluated geographic scales of variance for 17 landscape pattern indices, and compared stratification by ecoregions, administrative units, and watersheds. Ecoregions accounted for 65% to 75% of the total variance of percent agriculture and percent forest because dominant land cover is included in ecoregional definitions. In contrast, ecoregions explained only 13% to 34% of the variance of seven other pattern indices. After accounting for differences in amount of forest, ecoregions explained less than 5% of the variance of eight forest pattern indices. None of the stratifications tested would be effective mapping units for environmental management because within-unit variance of land-cover pattern is typically two to four times larger than between-unit vanance.