Mattson Kimberly M, Angermeier Paul L
Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0321, USA.
Environ Manage. 2007 Jan;39(1):125-38. doi: 10.1007/s00267-005-0238-7. Epub 2006 Nov 22.
Conservation planning aims to protect biodiversity by sustainng the natural physical, chemical, and biological processes within representative ecosystems. Often data to measure these components are inadequate or unavailable. The impact of human activities on ecosystem processes complicates integrity assessments and might alter ecosystem organization at multiple spatial scales. Freshwater conservation targets, such as populations and communities, are influenced by both intrinsic aquatic properties and the surrounding landscape, and locally collected data might not accurately reflect potential impacts. We suggest that changes in five major biotic drivers-energy sources, physical habitat, flow regime, water quality, and biotic interactions-might be used as surrogates to inform conservation planners of the ecological integrity of freshwater ecosystems. Threats to freshwater systems might be evaluated based on their impact to these drivers to provide an overview of potential risk to conservation targets. We developed a risk-based protocol, the Ecological Risk Index (ERI), to identify watersheds with least/most risk to conservation targets. Our protocol combines risk-based components, specifically the frequency and severity of human-induced stressors, with biotic drivers and mappable land- and water-use data to provide a summary of relative risk to watersheds. We illustrate application of our protocol with a case study of the upper Tennessee River basin, USA. Differences in risk patterns among the major drainages in the basin reflect dominant land uses, such as mining and agriculture. A principal components analysis showed that localized, moderately severe threats accounted for most of the threat composition differences among our watersheds. We also found that the relative importance of threats is sensitive to the spatial grain of the analysis. Our case study demonstrates that the ERI is useful for evaluating the frequency and severity of ecosystem-wide risk, which can inform local and regional conservation planning.
保护规划旨在通过维持代表性生态系统内自然的物理、化学和生物过程来保护生物多样性。通常，用于衡量这些组成部分的数据并不充分或无法获取。人类活动对生态系统过程的影响使完整性评估变得复杂，并且可能在多个空间尺度上改变生态系统组织。淡水保护目标，如种群和群落，受到内在水生特性和周边景观的影响，而本地收集的数据可能无法准确反映潜在影响。我们建议，五个主要生物驱动因素——能源、物理栖息地、水流状况、水质和生物相互作用——的变化可用作替代指标，向保护规划者通报淡水生态系统的生态完整性。对淡水系统的威胁可根据其对这些驱动因素的影响进行评估，以概述对保护目标的潜在风险。我们制定了一种基于风险的方案，即生态风险指数（ERI），以识别对保护目标风险最小/最大的流域。我们的方案将基于风险的组成部分，特别是人为压力源的频率和严重程度，与生物驱动因素以及可绘制的土地和水利用数据相结合，以提供流域相对风险的总结。我们通过对美国田纳西河上游流域的案例研究来说明我们方案的应用。该流域主要排水区域的风险模式差异反映了主导土地利用方式，如采矿和农业。主成分分析表明，局部的、中度严重的威胁占我们流域间威胁构成差异的大部分。我们还发现，威胁的相对重要性对分析的空间粒度很敏感。我们的案例研究表明，ERI可用于评估全生态系统风险的频率和严重程度，这可为地方和区域保护规划提供参考。
