The Species Problem and Conservation: What are We Protecting?

Abstract: Although conservation biologists base most of their activities on species taxa, they have participated little in the debate of systematists and evolutionary biologists about the recognition and nature of species. It is clear from this debate that there is no agreement on what species are, how they should be delimited, or what they represent. But in conservation science, and particularly in the selection, design and management of protected areas, species are either treated as types or as evolutionary units. A typological view of species may lead to a failure to protect the real diversity of life in the long term, if conservation priorities are set on the basis of species numbers or on circumscriptions of endangered, threatened, or endemic species taxa that result from the use of different species concepts. Considering species as typological entities may also lead workers to disregard geographic variation and to neglect the problem of deciding which level of variability to protect. It may even affect the goal of maintaining the evolutionary potential of organisms, if the focus is placed on the preservation of a sample of the existing types in populations that will persist as little changed as possible. When species are considered as evolutionary units, attention is shifted from the level of species to that of populations and metapopulations. Problems may still arise if these populations are considered in the context of species taxa, particularly if their composition is managed or if indicator species are used. A closer interaction between systematists and conservation biologists is suggested. Although the pressures of time and the difficulties faced by conservation biologists cannot be denied, considering the species problem more critically may result in recognizing the limitations of the taxonomic information used; it may also contribute to the refinement of the concepts and methods involved in their activities, making them more congruent with the nature of biological diversity.