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| Wade, Timothy G; U.S. Environmental Protection Agency, National Exposure Research Laboratory; wade.timothy@epa.gov; Riitters, Kurt; U.S. Forest Service; kriitters@fs.fed.us; Wickham, James D; U.S. Environmental Protection Agency, National Exposure Research Laboratory; wickham.james@epa.gov; Jones, K. Bruce; U.S. Environmental Protection Agency, National Exposure Research Laboratory; jones.bruce@epa.gov. |
| Because human land uses tend to expand over time, forests that share a high proportion of their borders with anthropogenic uses are at higher risk of further degradation than forests that share a high proportion of their borders with non-forest, natural land cover (e.g., wetland). Using 1-km advanced very high resolution radiometer (AVHRR) satellite-based land cover, we present a method to separate forest fragmentation into natural and anthropogenic components, and report results for all inhabited continents summarized by World Wildlife Fund biomes. Globally, over half of the temperate broadleaf and mixed forest biome and nearly one quarter of the tropical rainforest biome have been fragmented or removed by humans, as opposed to only 4% of the boreal... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Forest fragmentation; Forest pattern; Global; Risk assessment; Targeting. |
| Ano: 2003 |
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| Riitters, Kurt; U.S. Forest Service; kriitters@fs.fed.us; Wickham, James D; U.S. Environmental Protection Agency, National Exposure Research Laboratory; wickham.james@epa.gov; O'Neill, Robert; ; eoneill@attglobal.net; Jones, K. Bruce; U.S. Environmental Protection Agency, National Exposure Research Laboratory; jones.bruce@epa.gov; Smith, Elizabeth; U.S. Environmental Protection Agency, National Exposure Research Laboratory; smith.betsy@epa.gov. |
| We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 x 9 pixels, “small” scale) to 59,049 km 2 (243 x 243 pixels, “large” scale) were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined) from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents,... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Biogeography; Edge effect; Forest fragmentation; Geographic information systems; Global patterns; Land-cover map; Landscape ecology; Modeling; Perforated forest; Remote sensing; Satellite imagery; Spatial pattern. |
| Ano: 2000 |
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| Riitters, Kurt; U.S. Forest Service; kriitters@fs.fed.us; Wickham, James; U.S. Environmental Protection Agency; wickham.james@epamail.epa.gov; Coulston, John; North Carolina State University; jcoulston@fs.fed.us. |
| The question of incorporating road maps into U.S. national assessments of forest fragmentation has been a contentious issue, but there has not been a comparative national analysis to inform the debate. Using data and indices from previous national assessments, we compared fragmentation as calculated from high-resolution land-cover maps alone (Method 1) and after superimposing detailed road maps (Method 2). There was more overall fragmentation with Method 2. However, because roads were often adjacent to other nonforest land cover, Method 1 typically detected > 80% of the forest edge and > 88% of the fragmentation of core, i.e., intact, forest that was detected by Method 2. Indices based on individual patch size changed much more for Method 2;... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: United States; Ecological assessments; Land-cover maps; Landscape patterns; Road maps; Forest fragmentation. |
| Ano: 2004 |
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