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331.
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 ecosystemwide risk, which can inform
local and regional conservation planning. 相似文献