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6. There is a growing scientific consensus that species are disappearing at rates never before witnessed on the planet. But there is also controversy over those rates and the risks they entail. The world is losing precisely those species about which it knows nothing or little; they are being lost in the remotest habitats. The growing scientific concern is relatively new and the data base to support it fragile. But it firms yearly with each new field report and satellite study.
7. Many ecosystems that are rich biologically and promising in material benefits are severely threatened. Vast stocks of biological diversity are in danger of disappearing just as science is learning how to exploit genetic variability through the advances of genetic engineering. Numerous studies document this crisis with examples from tropical forests, temperate forests, mangrove forests, coral reefs, savannas, grasslands, and arid zones.[1] Although most of these studies are generalized in their documentation and few offer lists of individual species at risk or recently extinct, some present species-by-species details. (See Box 6–1.)
8. Habitat alteration and species extinction are not the only threat. The planet is also being impoverished by the loss of races and varieties within species. The variety of genetic riches inherent in one single species can be seen in the variability manifested in the many races of dogs, or the many specialized types of maize developed by breeders.[2]
9. Many species are losing whole populations at a rate that quickly reduces their genetic variability and thus their ability to adapt to climatic change and other forms of environmental adversity. For example, he remaining gene pools of major crop plants such as maize and rice amount to only a fraction of the genetic diversity they harboured only a few decades ago, even though the species themselves are anything but threatened. Thus there can be an important difference between loss of species and loss of gene reservoirs.
10. Some genetic variability inevitably will be lost, but all species should be safeguarded to the extent that it is technically, economically, and politically feasible. The genetic landscape is constantly changing through evolutionary processes, and there is more variability than can be expected to be protected by explicit government programmes. So in terms of genetic conservation, governments must be selective, and ask which gene reservoirs most merit a public involvement in protective measures. However, as a more general proposition, governments should enact national laws and public policies that encourage individual, community, or corporate responsibility for the protection of gene reservoirs.
11. But before science can focus on new ways to conserve species, policy makers and the general public for whom policy is made must grasp the size and the urgency of the threat. Species that are important to human welfare are not just wild plants that
are relatives of agricultural crops, or animals that are harvested. Species such as earthworms, bees, and termites may be
- ↑ W.B. Banage, 'Policies for the Maintenance of Biological Diversity', prepared for WCED, 1986: P.R. Ehrlich and A.H. Ehrlich, Extinction (New York: Random House, 1981); D. Western (ed.), Conservation 2100, Proceedings of Wildlife Conservation International and New York Zoological Society Conference. 21-24 October 1986 (New York: Zoological Society, in press); N. Myers, 'Tropical Deforestation and Species Extinctions, The Latest News' Futures, October 1985; R. Lewin, 'A Mass Extinction Without Asteroids', Science, 3 October 1986; P.H. Raven, 'Statement from Meeting of IUCN/WWF Plant Advisory Group', Las Palmas, Canary Islands, 24-25 November 1985; M.E. Soule (ed.), Conservation Biology: Science of Scarcity and Diversity (Sunderland, Mass.: Sinauer Associates, 1986); E.O, Wilson (ed.), Biodiversity, Proceedings of National Forum held by National Academy of Sciences and Smithsonian Institution. 21-24 September 1986 (Washington, DC: National Academy Press, forthcoming).
- ↑ O.H. Frankel and M.E. Soule, Conservation and Evolution (Cambridge: Cambridge University Press, 1981): Schonewald-Cox et al. (eds.), Genetics and Conservation (Menlo Park, Calif.: Benjamin/Cummings Publishing Company Inc., 1983).
