Effects of supportive breeding on the genetically effective population size

Biological Conservation 1992, 60, 63-72

Selected Abstracts The abstracts reproduced here have been selected from the coverage of Ecological Abstracts. Further information on Ecological Abstracts, and the associated online database GEOBASE is available from Elsevicr]Geo Abstracts, Regency House, 34 Duke Street, Norwich NR3 3AP, UK. 92Z/00004 Habitat structure and the design of nature reserves M . B . Usher, in: Habitat structure, ed S.S. Bell & others, (Chapman & Hall), 1991, pp 373-391. Examines some of the concepts inherent in deciding whether or not the shape of nature reserves is important, paying attention to species-area relationships. Limestone pavements in Yorkshire are used as an example. Shape appears to be more important when small reserves are db:e~lgare~tablished, than when large national p _ad_SomareAubethmog r

NATURE CONSERVATION

General 92Z/00001 Six biological reasons why the Endangered Species Act doesn't work - and what to do about it D. J. Rohif, Conservation Biology, 5(3), 1991, pp 273-282. The Endangered Species Act, the United State's strongest legal tool for conserving biodiversity, contains serious biological flaws. The statute itself, as well as agency regulations and policies that implement the law, include provisions that fail to account accurately for important biological concepts such as ecosystem conservation, patch dynamics, and the probabilistic nature of stochastic threats to a species' persistence. However, the Endangered Species Act gives interested individuals and groups several opportunities to provide input into the process of managing threatened and endangered species. Conservation biologists should practice focused advocacy by taking advantage of such opportunities to steer law in a more biologically sound direction. -from Author

92Z/00005 The theory of wildlife corridor capability M . E . Sonic & M. E. Gilpin, in: Nature conservation 2: the role of corridors, ed D.A. Saunders & R.J. Hobbs, (Surrey Beatty), 1991, pp 3-8. Decisions about the identity of the species for which the corridor is designed must be made early in the analysis. Corridor capability analysis depends on a thorough grasp of the life history and demography of the candidate species. The potential benefits of corridors for specific species must be weighed against the potential detrimental effects for the ecosystems as wholes. A computer simulation of corridor capability for animals suggested: 1) optimum corridor wxdth depends on the strength of the edge effect - tae higher the relative mortality rate of the edge, the wider the corridor must be; 2) any departures from linearity, even for relatively intelligent animals, may be deleterious; and 3) the shape of corridors may be important. -from Authors

92Z/00002 Effects of supportive breeding on the genetically effective population size N. Ryman & L. Laikre, Conservation Biology, 5(3), 1991, pp 325-329. Discusses the reduction of the genetically effective population size that may result from breeding-release programs aimed at supporting natural populations. Typically, in such programs a fraction of the wildparents (or their offspring) axe brought into captivity for reproduction or preferential survival, and the offspring are released into the natural habitat where they mix with wild conspecifies. In such supportive breeding, no exogenous genes are introduced into the overall population. The logic of supportive breeding is generally to increase survival through breeding in a protected captive environment, but this process also implies that the reproductive rate of one segment of the overall population is favored, which results in an increase in the total variance of family size, a parameter of critical importance to the genetically effective size of the population. -from Authors

92Z/00006 The visualization of corridors in the landscape using SPOT data H. Gulinck, O. Walpot, P. Janssens & I. Dries, in: Nature conservation 2: the role of corridors, ed D.A. Saunders & R.J. Hobbs, (Surrey Beatty), 1991, pp 9-17. Using SPOT images for C Belgium, methods and techniques are explored at three levels: 1) the identification of wooded corridor elements through image analysis and classification is discussed; 2) the results of this analysis are used in a series of structural image techniques, which are useful for modelling hypothetical functional corridors in the landscape; 3) suggestions are given for the use of remote sensing for the planning and evaluation of corridors in rural landscapes, through the analysis of rural functions, other than nature conservation. -from Authors 92Z/00007 Application of biological moeiling and GIS to identify regional wildlife corridors T.W. Norton & H. A. Nix, in: Nature conservation 2: the role of corridors, od D.A. Saunders & R J . Hobbs, (Surrey Beatty), 1991, pp 19-26. Presently it is not possible to evaluate accurately the role of most areas set aside as wildlife corridors. Recent advances in computer-based methodologies (biological modelling and geographic information systems) provide an mproved basis for the analysis of ecological relationships. xamples of this approach are shown using a biophysical data base on forest communities in NE Queensland and research from sub-alpine forests in SE Australia. -from Authors

92Z/00003 A conceptual framework for evaluating and quantifying naturalness J. E. Anderson, Conservation Biology, 5(3), 1991, pp 347-352. Three indices of naturalness are proposed: 1) the degree to which the system would change if humans were removed; 2) the amount of cultural energy required to maintain the functioning of the system as it currently exists; and 3) the complement of native species currently in an area compared with the suite of species in the area prior to settlement. These complementary indices provide a conceptual firamework for evaluating naturalness. -from Author Biological Conservation 0006-3207?92/$05.00 © 1992 Elsevier Science Publishers Ltd. 63