Refining the Use of Habitat Equivalency Analysis

Abstract

When natural resources are injured or destroyed in violation of certain U.S. federal or state statutes, government agencies have the responsibility to ensure the public is compensated through ecological restoration for the loss of the natural resources and services they provide. Habitat equivalency analysis is a service-to-service approach to scaling restoration commonly used in natural resource damage assessments. Calculation of the present value of resource services lost due to injury and gained from compensatory restoration projects is complicated by assumptions concerning the within-time period crediting of losses and gains. Conventional beginning-of-period accounting leads to an underestimate of the loss due to injury and an overestimate of the gains from compensatory projects in cases with linear recovery projections. The resulting compensatory requirement is often insufficient to offset the true loss suffered by the public. Two algebraic equations are offered to correct for these estimation inaccuracies, and a numerical example is used to illustrate the magnitude of error for a typical, though hypothetical, injury scenario.

A Framework for Implementing and Valuing Biodiversity Offsets in Colombia: A Landscape Scale Perspective

“…Restoration offsets may take many years before conservation benefits mature. This time lag represents a loss for biodiversity and should be accounted for in estimates of ecological gains [47]. We propose that the Colombian government account for this loss by estimating the time to maturity of a restoration action and apply a discount rate, a commonly used method for estimating the present value of future values.…”

The Evolution of Non-Market Valuation of U.S. Coastal and Marine Resources

“…For most of these cases, a separate non-monetary approach, termed habitat equivalency analysis (HEA), has been used to estimate the loss of ecological services, which can be services performed by a natural resource for the benefit of another natural resource, not solely for humans (the commonly used definition of ecosystem services). HEA uses a combination of site-specific ecological data and expert judgment based on the literature to determine the losses in ecological services from a contamination event and potential gains from restoration (Thur 2007). Cases will often therefore, where needed, have an evaluation of impacted ecological services in addition to impacted human use services.…”

Coral reef metrics and habitat equivalency analysis

“…In practice, however, this time period is often lengthy, resulting in an interim net service loss (where services are defined in an ecological context as outcomes resulting from biophysical processes within an ecosystem [23] and in an NRDA context as natural resource functions that benefit another natural resource and/or the public [24]). In addition, if the injured resource cannot be restored fully to baseline conditions, there is a service loss in perpetuity.…”

“…REA is a resource-toresource method that references the number of organisms lost and gained, and HEA is a service-to-service method that references habitat area lost and gained [42]. The two methods are algebraically identical and are used to calculate the quantity of compensatory restoration that will generate natural resource services equivalent to service losses due to an injury [24,26,[41][42][43][44]. Service losses and compensatory benefits are quantified in non-monetized units such as discounted service-acre-years (DSAYs).…”