Habitat and Resource Equivalency Analysis: 30 Years of Lessons Learned and a Look to the Future

ABSTRACT Natural Resource Damage Assessment (NRDA) under the Oil Pollution Act of 1990 (OPA) is a process used to determine the amount of compensation due to the public for natural resource injuries arising from oil spills. Two models, Resource Equivalency Analysis (REA) and Habitat Equivalency Analysis (HEA), are used in essentially all OPA NRDAs to compute compensatory restoration requirements. REA is applied when members of wildlife populations are injured: usually mortality or a loss of reproduction among a species of bird, turtle, marine mammal, or fish. HEA is used when habitats are injured: usually oiling of beaches, wetlands, or sediments. The models are often implemented in a cooperative setting with input from both the Responsible Party and the Trustees. In this setting the models provide a structure for organizing negotiations and identifying the types of agreements that need to be reached before restoration can be identified and “right sized.” The models also have a technical basis in economic theory that is fully justified, but only in particular, limited circumstances. This technical basis is the only means of assuring the Trustees, RPs, and stakeholders that the NRDA process has identified an appropriate level of compensation. When the circumstances of a spill do not approximate those in which HEA and REA are defensible, creative solutions are needed to adjust the models to the circumstances of the case if they are to provide a convincing basis for scaling restoration and reaching resolution. This paper identifies the circumstances under which REA and HEA are fully defensible as well as 35 years of evolving adjustments designed to make them “work” when applied to real-world cases they do not quite fit. We also look to the future and how climate change may alter restoration scaling.

Restoration Scaling Approaches to Addressing Ecological Injury: The Habitat-Based Resource Equivalency Method

Natural resource trustee agencies must determine how much, and what type of environmental restoration will compensate for injuries to natural resources that result from releases of hazardous substances or oil spills. To fulfill this need, trustees, and other natural resource damage assessment (NRDA) practitioners have relied on a variety of approaches, including habitat equivalency analysis (HEA) and resource equivalency analysis (REA). The purpose of this paper is to introduce the Habitat-Based Resource Equivalency Method (HaBREM), which integrates REA’s reproducible injury metrics and population modeling with HEA’s comprehensive habitat approach to restoration. HaBREM is intended to evaluate injury and restoration using organisms that use the habitat to represent ecological habitat functions. This paper seeks to expand and refine the use of organism-based metrics (biomass-based REA), providing an opportunity to integrate sublethal injuries to multiple species, as well as the potential to include error rates for injury and restoration parameters. Applied by NRDA practitioners in the appropriate context, this methodology can establish the relationship between benefits of compensatory restoration projects and injuries to plant or animal species within an affected habitat. HaBREM may be most effective where there are appropriate data supporting the linkage between habitat and species gains (particularly regionally specific habitat information), as well as species-specific monitoring data and predictions on the growth, density, productivity (i.e., rate of generation of biomass or individuals), and age distributions of indicator species.