Metric System for Evaluating Off-site Mitigation for Ecosystem Services and Wildlife Habitat in Sagebrush Ecosystems

摘要

A fundamental concept of mitigation is that it is possible to compensate for impacts to ecosystem services at one site (the impact site) by replacing or increasing the same services at another site (the mitigation site). A challenge in the use of off-site mitigation is assuring that ecosystem services, including wildlife habitat, produced by off-site mitigation are commensurate with on-site impacts. Recent increases in energy developments within the sagebrush biome have raised concerns about impacts associated with these activities and efforts to mitigate those impacts. To help address these concerns, we developed a metric system to quantify impact losses and mitigation benefits based on a combination of NRCS Ecological Sites, existing vegetation conditions, and habitat assessment conducted at the landscape level for sagebrush-associated wildlife species. Changes to vegetation conditions within sagebrush ecosystems produced by on-the-ground mitigation treatments or by impacts are quantified based on comparison to a reference standard developed from the Ecological Site Description for the specific plant communities associated with either the mitigation or impact site. Wildlife benefits are also evaluated at a landscape scale using models that quantify the gains or losses in habitat quality associated with the mitigation or development activities. This metric system provides a standardized way of quantifying gains and losses of ecosystem services and wildlife habitat associated with impacts and mitigation which will help to ensure that gains associated with mitigation activities are commensurate with losses resulting from development.