Incorporating climate change into Endangered Species Act decisions: Case studies from aquatic systems

Background/Question/Methods

A changing climate makes the conservation of marine, estuarine, and freshwater organisms even more challenging than these efforts would normally be due to the strong links between climatic and aquatic processes, the dynamism of aquatic systems, the large migrations of many aquatic organisms, and the relative uncertainty of the pace and magnitude of climate-related changes in some areas. Changing environmental conditions (including ocean acidification) have the potential not only to worsen the conditions for imperiled species, but also to pose new scientific and societal challenges to their conservation especially within the context of statutory mandates such as the U.S. Endangered Species Act (ESA). Recent court decisions have affirmed the importance of considering climate change in determinations under the ESA. Recognizing the need to address this issue, the U.S. National Marine Fisheries Service (NMFS) conducted eight case studies to explore approaches for including climate change impacts in ESA decision-making regarding marine and anadromous species. The case studies fell into three categories of ESA-related conservation planning: (1) long-term risk assessment (e.g., decisions to list or de-list species or locations); (2)  long-term planning and prioritization (e.g., recovery planning and conservation strategies); and (3) shorter-term projections and evaluation of immediate impacts (e.g action-specific evaluations). 

Results/Conclusions

This study identified three key challenges and possible solutions for incorporating climate change information into ESA decision-making for marine and anadromous species.  First, there are high levels of uncertainty about climatic impacts in marine and aquatic systems, particularly on how species respond to climate-related changes.  The study team recommended developing conceptual models linking climate characteristics, physical and biotic habitat conditions, and species responses to provide the foundation for identifying life stages, populations, species or habitats most vulnerable to a changing climate, increase the transparency of the effort, identify key information needs and allow decision-makers to consider management options across a range of scenarios. Second, the study found that time frames of both climate projections and the effects of an anthropogenic actions had a substantial impact on estimated risk faced by species.  Third, that climate change is likely to alter habitat suitability, with areas currently occupied by species likely to become unsuitable and vice versa.  This means the uncertainties associated with long-term designations of critical habitat or other long-term planning efforts may be increased.  Using scenario planning approaches can help decision-makers evaluate and reduce risk levels for various habitat conservation options.