Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado 80523-1474, USA.
Ecol Appl. 2011 Oct;21(7):2445-58. doi: 10.1890/10-1701.1.
Effects of land-use change on the conservation of biodiversity have become a concern to conservation scientists and land managers, who have identified loss and fragmentation of natural areas as a high-priority issue. Despite urgent calls to inform national, regional, and state planning efforts, there remains a critical need to develop practical approaches to identify where important lands are for landscape connectivity (i.e., linkages), where land use constrains connectivity, and which linkages are most important to maintain network-wide connectivity extents. Our overall goal in this paper was to develop an approach that provides comprehensive, quantitative estimates of the effects of land-use change on landscape connectivity and illustrate its use on a broad, regional expanse of the western United States. We quantified loss of habitat and landscape connectivity for western forested systems due to land uses associated with residential development, roads, and highway traffic. We examined how these land-use changes likely increase the resistance to movement of forest species in non-forested land cover types and, therefore, reduce the connectivity among forested habitat patches. To do so, we applied a graph-theoretic approach that incorporates ecological aspects within a geographic representation of a network. We found that roughly one-quarter of the forested lands in the western United States were integral to a network of forested patches, though the lands outside of patches remain critical for habitat and overall connectivity. Using remotely sensed land cover data (ca. 2000), we found 1.7 million km2 of forested lands. We estimate that land uses associated with residential development, roads, and highway traffic have caused roughly a 4.5% loss in area (20 000 km2) of these forested patches, and continued expansion of residential land will likely reduce forested patches by another 1.2% by 2030. We also identify linkages among forest patches that are critical for landscape connectivity. Our approach can be readily modified to examine connectivity for other habitats/ecological systems and for other geographic areas, as well as to address more specific requirements for particular conservation planning applications.
土地利用变化对生物多样性保护的影响已成为保护科学家和土地管理者关注的焦点，他们已将自然区域的丧失和破碎化确定为高度优先事项。尽管迫切呼吁为国家、地区和州的规划工作提供信息，但仍迫切需要制定实用方法来确定重要土地在景观连通性（即连接）中的位置，土地利用对连通性的限制，以及维护网络范围连通性程度最重要的连接。我们在本文中的总体目标是开发一种方法，该方法可全面、定量地估计土地利用变化对景观连通性的影响，并说明其在美国西部广阔的区域范围内的应用。我们量化了由于与住宅开发、道路和高速公路交通相关的土地利用而导致西部森林系统丧失栖息地和景观连通性的情况。我们研究了这些土地利用变化如何可能增加森林物种在非森林土地覆盖类型中的迁移阻力，从而降低森林生境斑块之间的连通性。为此，我们应用了一种图论方法，该方法将生态方面纳入网络的地理表示中。我们发现，美国西部大约四分之一的森林土地是森林斑块网络的组成部分，尽管斑块外的土地对栖息地和整体连通性仍然至关重要。使用遥感土地覆盖数据（约 2000 年），我们发现了 170 万平方千米的森林土地。我们估计，与住宅开发、道路和高速公路交通相关的土地利用导致这些森林斑块的面积减少了约 4.5%（20000 平方千米），并且到 2030 年，住宅用地的持续扩张可能会使森林斑块减少 1.2%。我们还确定了对景观连通性至关重要的森林斑块之间的联系。我们的方法可以轻松修改，以研究其他栖息地/生态系统和其他地理区域的连通性，以及满足特定保护规划应用的更具体要求。
