When Are Peripheral Populations Valuable for Conservation?

A great deal of effort is spent protecting geographically peripheral populations of widespread species. We consider under what conditions it is appropriate to expend resources to protect these populations. The conservation value of peripheral populations depends upon their genetic divergence from other conspecific populations. Peripheral populations are expected to diverge from central populations as a result of the interwoven effects of isolation, genetic drift, and natural selection. Available empirical evidence suggests that peripheral populations are often genetically and morphologically divergent from central populations. The long-term conservation of species is likely to depend upon the protection of genetically distinct populations. In addition, peripheral populations are potentially important sites of future speciation events. Under some circumstances, conservation of peripheral populations may be beneficial to the protection of the evolutionary process and the environmental systems that are likely to generate future evolutionary diversity.     

Usefulness of the Umbrella Species Concept as a Conservation Tool

Abstract:  In the face of limited funding, knowledge, and time for action, conservation efforts often rely on shortcuts for the maintenance of biodiversity. The umbrella species concept—proposed as a way to use species requirements as a basis for conservation planning—has recently received growing attention. We reviewed the literature to evaluate the concept's general usefulness. An umbrella species is defined as a species whose conservation is expected to confer protection to a large number of naturally co-occurring species. This concept has been proposed as a tool for determining the minimum size for conservation areas, selecting sites to be included in reserve networks, and setting minimum standards for the composition, structure, and processes of ecosystems. Among the species suggested as potential umbrellas, most are large mammals and birds, but invertebrates are increasingly being considered. Eighteen research papers, most of which were based on hypothetical reserves or conservation networks, have provided evaluations of umbrella species schemes. These show that single-species umbrellas cannot ensure the conservation of all co-occurring species because some species are inevitably limited by ecological factors that are not relevant to the umbrella species. Moreover, they provide evidence that umbrella species from a given higher taxon may not necessarily confer protection to assemblages from other taxa. On the other hand, multi-species strategies based on systematic selection procedures (e.g., the focal species approach) offer more compelling evidence of the usefulness of the concept. Evaluations of umbrella species schemes could be improved by including measures of population viability and data from many years, as well as by comparing the efficiency of the proposed scheme with alternative management strategies.     

Lands for Long-Term Research in Conservation Biology

Abstract: Success in conservation biology depends upon a synergistic combination of short-term tactics and long-term strategies. Although the former are often necessary to forestall immediate habitat losses, the latter provide the critical framework of understanding needed to develop effective short-term priorities. Although many conservation biologists now emphasize short-term tactics, prudence dictates the concomitant establishment of long-term research projects aimed at answering fundamental ecological questions.
One deterrent to amassing such long-term data bases, aside from time and funding, is a lack of suitable sites where such studies can be conducted on a large scale. We describe two established major land-holding networks in the United States that could serve as appropriate places to develop long-term studies: the National Science Foundation's Long-Term Ecological Research (LTER) sites, and the US. Department of Energy's National Environmental Research Parks (NERPs). Because they consist of established research facilities, both networks can provide conservation biologists with "low-cost" baseline information on ecological processes, as well as access to a number of representative terrestrial and aquatic habitats under more or less "controlled" conditions suitable for long-term studies. We recommend that conservation biologists explore the possibility of using these or similarly available sites in their research programs.