Landscape trends in Mid-Atlantic and southeastern United States ecoregions
Landscape trends in Mid-Atlantic and southeastern United States ecoregions
复制标题
DOI：
10.1007/s00267-003-0078-2
复制
发表时间：
2003-11-01
影响因子：
3.5
通讯作者：
Loveland, TR
中科院分区：
文献类型：
--
作者：
Griffith, JA;Stehman, SV;Loveland, TR
景观格局和组成指标是广泛监测变化和将变化与人类和生态过程联系起来的潜在指标。我们使用20公里× 20公里采样块的概率样本来表征美国五个生态区的景观组成和格局：大西洋中部沿海平原、东南平原、北部皮埃蒙特、皮埃蒙特和蓝岭山脉。每个样块获得了1972 - 2000年5个日期的土地利用/土地覆盖（LULC）数据。分析的重点是量化各生态区景观格局指标的变化趋势，并比较各生态区土地覆盖比例和格局指标的变化趋势。对景观格局的反复测量分析表明，从20世纪70年代初到2000年，所有五个生态区都有向更细粒度景观发展的统计显著趋势。生态上重要的森林覆盖等级也随着时间的推移变得更细粒度（即，更多的和更小的森林斑块）。不同生态区的LULC、森林边缘和森林相似邻接率的变化趋势不同。这些结果表明，生态区提供了一种地理上连贯的方式来划分美国国家土地利用和土地覆盖变化的故事。本研究为美国东南部的LULC变化提供了新的信息。从20世纪30年代到80年代对该地区的研究表明，景观破碎化减少，森林百分比增加，而本研究显示森林破碎化增加，森林覆盖减少。
Landscape pattern and composition metrics are potential indicators for broad-scale monitoring of change and for relating change to human and ecological processes. We used a probability sample of 20-km x 20-km sampling blocks to characterize landscape composition and pattern in five US ecoregions: the Middle Atlantic Coastal Plain, Southeastern Plains, Northern Piedmont, Piedmont, and Blue Ridge Mountains. Land use/land cover (LULC) data for five dates between 1972 and 2000 were obtained for each sample block. Analyses focused on quantifying trends in selected landscape pattern metrics by ecoregion and comparing trends in land cover proportions and pattern metrics among ecoregions. Repeated measures analysis of the landscape pattern documented a statistically significant trend in all five ecoregions towards a more fine-grained landscape from the early 1970s through 2000. The ecologically important forest cover class also became more fine-grained with time (i.e., more numerous and smaller forest patches). Trends in LULC, forest edge, and forest percent like adjacencies differed among ecoregions. These results suggest that ecoregions provide a geographically coherent way to regionalize the story of national land use and land cover change in the United States. This study provides new information on LULC change in the southeast United States. Previous studies of the region from the 1930s to the 1980s showed a decrease in landscape fragmentation and an increase in percent forest, while this study showed an increase in forest fragmentation and a loss of forest cover.