Habitat destruction and degradation are the most pervasive threats to biodiversity and contribute to the endangerment of many threatened or endangered species. The Endangered Species Act protects the ecosystems on which the endangered species depend through the mitigation hierarchy: avoid, reduce or compensate for negative impact to habitat. A piecemeal approach to mitigation, whereupon each project is compensated for separately often results in small non-sustainable parcels of habitat scattered throughout the landscape, is discouraged while consolidated market-based mitigation approaches are encouraged. Proactive planning and pooling of habitat mitigation areas can result in more cohesive, larger areas being conserved. Conservation banking, a key method of off-site consolidated mitigation, has been shown to be beneficial. However, there are barriers to implementing conservation banking; a major difficulty being a ready means of determining habitat mitigation debits and credits. It is especially difficult to determine debits and credits without having population presence data or detailed ground-level surveys. I developed a method of valuing habitat based on a characterization of landscape integrity from an individual species perspective. The methodology relies primarily on land use/land cover Geographic Information Systems (GIS) mapping, along with life history and home range/habitat use information for each species.
Results/Conclusions
An assessment using independent sightings data, multiple metrics, and 15 species of a variety of taxa confirms the reliability of the wildlife habitat values calculated. From the wildlife habitat values I developed a system that establishes both debits, the value of the habitat lost if land is developed, and credits, the increase in the value of the land if it is preserved and managed in perpetuity for the good of the species in question. All values are based on place-based decision-making. Debit and credit values can be used together as a practical, science-based tool in conservation banking, allowing reasonable, consistent, timely mitigation in the event of unavoidable development on areas of T&E habitat. Because the value of the habitat is taken into account, advance planning using the maps created by this model can nudge development either off or into marginal T&E habitat and away from valuable or core habitat. The financial incentives not to develop valuable or core habitat implied by the debits and credits will likely create a market force away from core habitat allowing a region to meet the goal of no net loss of threatened and endangered species habitat value.