Valuing Wildlife Crossings and Enhancements for Mitigation Credits (2020) / Chapter Skim
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Pages 30-37
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From page 30... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 27 3.0 POTENTIAL VALUATION METRICS FOR WILDLIFE CONNECTIVITY MITIGATION CREDITS One criticism of mitigation banking is the general lack of standardization of credit quantification and metrics. For conservation bank credits, which are typically based on a simple metric such as acres of habitat, the methods to quantify the value of the credits often differ among species, and even between USFWS field offices.
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From page 31... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 28 Table 2. Potential metrics to value wildlife connectivity mitigation, their potential units of measurement, and notes regarding their applicability Category Metric to Value Wildlife Crossings Unit of Measurement for Mitigation Credits Notes on Applicability to State DOTs a Conditionbased Area of highway footprint within the highway crossing zone used by focal species b, c Acres of impervious surface or highway project boundary Caltrans used this metric for SR-19 Laurel Curve in Santa Cruz County, California.
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From page 32... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 29 Category Metric to Value Wildlife Crossings Unit of Measurement for Mitigation Credits Notes on Applicability to State DOTs a Conditionbased Traffic volume b, c AADT or vehicles per hour Species-specific data about animal movement over highways with different AADT volumes would be necessary to quantify potential benefits or impacts to a given focal species. More credits could be generated for wildlife connectivity mitigation on high-volume highways or applied to transportation projects that increase traffic.
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From page 33... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 30 Category Metric to Value Wildlife Crossings Unit of Measurement for Mitigation Credits Notes on Applicability to State DOTs a Functionbased Genetic interchange of focal species b, c Change in genetic diversity in comparison to current generation Connectivity among populations reduces the negative effects of inbreeding and genetic drift, but it takes relatively little exchange between populations to maintain genetic diversity. DNA profiling of individuals using wildlife crossings or crossing highways is a technique that could be carried out in a relatively short period of two to three years, and methods exist to monitor many species via noninvasive genetic sampling (e.g., hair snares)
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From page 34... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 31 Category Metric to Value Wildlife Crossings Unit of Measurement for Mitigation Credits Notes on Applicability to State DOTs a Functionbased Population size(s) of focal species b, c Number of affected individual animals of focal species Although there is widespread agreement that effective wildlife connectivity mitigation has the potential to enhance population viability of species impacted by roads, few studies have empirically addressed this and there are many confounding factors.
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From page 35... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 32 Category Metric to Value Wildlife Crossings Unit of Measurement for Mitigation Credits Notes on Applicability to State DOTs a Traffic forecasting models and/or predictive models of land development b, c Predicted AADT or vehicles per hour Researchers have combined traffic demand forecasting models with wildlife connectivity models to predict the crossing locations where future mitigation would be necessary for grizzly bears. Avoided Cost Property damage, human injury, and/or death from WVCs b Number of WVCs over a specified time period (seasonal or annual)
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From page 36... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 33 metrics because they could incorporate existing ecological datasets and results from prior modeling efforts to predict ecological gain for multiple species. When evaluating potential metrics to value wildlife connectivity mitigation, it would be useful for state DOTs to assess their potential importance using an approach recommended by the National Research Council (2000)
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From page 37... ...
Valuing Wildlife Crossings and Enhancements for Mitigation Credits 34 federal agencies to evaluate potential metrics, as discussed below in section 4.2. Further transparency could also be provided if the working group's recommended metrics and quantification methods were analyzed under a planning process that includes an opportunity for public review and commenting.
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