摘要：Natural resource agencies worldwide must develop species recovery plans that specify threats, propose targets required for recovery, and evaluate the extent to which habitat alteration and restoration may influence species decline and recovery. To evaluate the impacts of proposed habitat alterations on species of conservation concern, standardized protocols may be adopted even when supporting data are scarce. For example, a habitat matrix was developed by the National Marine Fisheries Service (NMFS) to guide consultations under the Endangered Species Act for actions that may affect the functioning of the freshwater habitat used by several federally listed salmonid species. The habitat matrix has also been advocated as a tool for recovery planning by agencies apart from the NMFS, who could use it to define the habitat conditions assumed to be necessary for salmonid population viability and hence recovery. This use of the habitat matrix in a recovery context has not been evaluated, and, despite its widespread use as a regulatory tool, the empirical relationships between many of the habitat matrix variables and salmonid populations remain unexplored. By amassing data on habitat assessments and trends in fish abundance, we empirically evaluate the relationship between habitat matrix scores and salmonid population metrics. We found that abundance trends for populations of three species of threatened and endangered salmonids (chinook, coho, and steelhead) were unrelated to these habitat matrix assessments. This study reveals the danger of assuming quantitative relationships between habitat and organism and cautions against co-opting protocols from the regulatory realm for recovery planning for endangered species.
