As part of a symposium on “Defining species for threatened and endangered protection” Barbara Taylor, Ph.D., NOAA Fisheries Service, will discuss the need to explicitly consider uncertainty in taxonomy in conservation decisions. Species concepts continue to be a contentious, but largely philosophical debate among academic biologists. How differences between groups of organisms are identified, however, can have real, on-the-ground policy implications for which species receive legal protection under the federal Endangered Species Act.

Taylor brings her experience in designing management decision rules that acknowledge and deal with the high level of uncertainty resulting from typical cases with a dearth of data. She points out that while many fields of conservation science have advanced on how to make decisions when uncertainty is high, taxonomy has not.

Taxonomy has been an evidentiary field requiring a strong burden of proof to propose taxonomic changes such as new species. The high data requirement, particularly requiring morphological data from skull collections, has resulted in certain taxonomic groups (like whales) being at a disadvantage and likely under-representing the true taxonomic diversity.

Taylor illustrates the problem of taxonomic uncertainty with a case involving killer whales, which will likely be separated into multiple species or sub-species. The petition to list Southern Resident killer whales under the ESA revolved not around risk but rather on whether these whales met the definition of Distinct Population Segment used as the smallest unit to conserve under the ESA.

Taylor discusses the potential of incorporating uncertainty into taxonomic considerations, as is commonly done in other biological fields, to allow precautionary decision-making for the purposes of conservation. She illustrates such a possible route using a decision table that uses information on both risk and the likelihood of attaining more data quickly to place potential species or sub-species as designated for conservation purposes.

Source: NOAA Headquarters