 |  Conservation Biology: Foundations, Concepts, Applications Fred Van Dyke
The Conservation of Genetic Diversity
Chapter Synthesis| Genetics has played a multidimensional role in the development and practice of conservation biology. Increasing precision and quantification of the genetic characteristics of individuals and populations has given force, along with occasional dilemmas and confusion, to the Endangered Species Act and other laws that address the protection of species. In cases where taxonomic distinctness is an important criterion for setting conservation priorities, genetic analyses take pride of place in decisively answering questions of taxonomic status (Schemske et al. 1994).
The accelerating pace of development in genetic analysis and techniques has elevated captive breeding from being the art of a few specialists to a science that can be practiced with an increasingly uniform set of standards and protocols. Further, improved genetic techniques and analysis have changed captive breeding from an effort that once seemed a last desperate gamble into carefully coordinated programs with real potential for successful long-term species preservation and reintroduction of animals to natural areas. Genetic techniques also have made possible noninvasive and less labor-intensive sampling of wild populations, vastly enhancing the potential of genetic management.
The danger inherent in a period of such achievement and optimism in conservation genetics is that, improperly applied and incorrectly understood, genetic analyses can lead to inappropriate conclusions, incorrect management decisions, and disillusionment because of overinflated expectations. An overemphasis on genetic analysis, to the exclusion of other essential considerations of a population's identity or persistence, can lead to conclusions that may be not only inappropriate and wasteful, but also even absurd. In addition, genetic research in populations is at a stage in which highly sophisticated and widely available techniques make it possible to collect enormous amounts of data without any clear understanding of what such data mean in regard to population modeling, long-term survivorship, or reproductive performance. This problem is particularly acute in plant conservation efforts. For example, the U.S. Fish and Wildlife Service (1990) recovery plan for the endangered plant, Peter's mountain mallow (Iliamna corei), calls for collection of data on genetic variation and subsequent development of a population genetics model to determine the number of populations and effective population sizes required for long-term survival. Botanist Douglas Schemske and his coworkers, commenting on the plan, noted, "This emphasis on the genetics of conservation rarity is a clear case of overkill, as only four individuals of the mallow are known to exist in the wild" (Schemske et al. 1994). To avoid the inanity of such "conservation genetics overkill," conservation biologists must take pains to not misappropriate genetic techniques, to not seek excessive amounts of genetic information when it has little value for the immediate needs of conservation planning, and to understand the distinctive concepts and context of genetic techniques so that their results are properly understood and fully integrated with other sources of information and insight. Similarly, conservation biologists must choose their fights carefully, and not make the loss of every genetic variant a conservation crisis. As Rhymer and Simberloff (1996) put it regarding the threat of hybridization, "one cannot be exercised over every situation in which new genes are flowing into a distinctive population, or economic and emotional resources will be insufficient to win most of these battles." Finally, conservation biologists must understand that genetic analyses do not, in themselves, make management decisions, create conservation plans, or provide essential management data. Alone, genetic information will always be insufficient for achieving conservation goals. Nongenetic dimensions of a species' life history, environmental constraints, or population demography may be more important to the persistence of a species than the present state of its genetic diversity. Sophisticated techniques are no substitute for sound judgment and discerning biological insight into conservation efforts.
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2003 McGraw-Hill Higher Education