Bruggeman Douglas J, Jones Michael L
Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA.
Environ Manage. 2008 Oct;42(4):591-602. doi: 10.1007/s00267-008-9179-2. Epub 2008 Jul 16.
Many species of conservation concern are spatially structured and require dispersal to be persistent. For such species, altering the distribution of suitable habitats on the landscape can affect population dynamics in ways that are difficult to predict from simple models. We argue that for such species, individual-based and spatially explicit population models (SEPMs) should be used to determine appropriate levels of off-site restoration to compensate for on-site loss of ecologic resources. Such approaches are necessary when interactions between biologic processes occur at different spatial scales (i.e., local [recruitment] and landscape [migration]). The sites of restoration and habitat loss may be linked to each other, but, more importantly, they may be linked to other resources in the landscape by regional biologic processes, primarily migration. The common management approach for determining appropriate levels of off-site restoration is to derive mitigation ratios based on best professional judgment or pre-existing data. Mitigation ratios assume that the ecologic benefits at the site of restoration are independent of the ecologic costs at the site of habitat loss. Using an SEPM for endangered red-cockaded woodpeckers, we show that the spatial configuration of habitat restoration can simultaneously influence both the rate of recruitment within breeding groups and the rate of migration among groups, implying that simple mitigation ratios may be inadequate.
许多受保护关注的物种具有空间结构，需要扩散才能持续生存。对于此类物种，改变景观中适宜栖息地的分布可能会以简单模型难以预测的方式影响种群动态。我们认为，对于此类物种，应使用基于个体且具有空间明确性的种群模型（SEPMs）来确定合适的异地恢复水平，以补偿生态资源的就地损失。当生物过程之间的相互作用发生在不同空间尺度（即局部[繁殖]和景观[迁徙]）时，此类方法是必要的。恢复地点和栖息地丧失地点可能相互关联，但更重要的是，它们可能通过区域生物过程（主要是迁徙）与景观中的其他资源相联系。确定合适的异地恢复水平的常见管理方法是基于最佳专业判断或现有数据得出缓解比例。缓解比例假定恢复地点的生态效益与栖息地丧失地点的生态成本无关。通过对濒危的红头啄木鸟使用SEPM，我们表明栖息地恢复的空间配置可以同时影响繁殖群体内的繁殖率和群体间的迁徙率，这意味着简单的缓解比例可能并不足够。
