General discussion

Abstract

V. C. Wynne-Edwards ( Department of Zoology, University of Aberdeen ). In opening the final discussion the Chairman said we had heard a great deal about the value of science to nature reserves, but what are the values of nature reserves to science? In giving an example of this, may I begin by taking up a remark made a few minutes ago by Professor Bradshaw about the quick effects to be expected of natural selection, in protecting the gene-pools of native trees and other plants in nature reserves from adulteration by allochthonous strains of the same species, if these were introduced to the reserves from elsewhere. Let me remind you that not all the effects of natural selection are equally rapid in suppressing non-adaptive genes. The selective advantage or disadvantage of some mutations may not be put to the test for many generations. If this were not so, and if selection could only result in maximizing the fitness of the individual in the short term, then the evolutionist could not explain the origin of ‘prudential’ adaptations, such as those that control population density and population growth in many animals. These usually involve altruistic responses, that is to say, the sacrifice of individual advantage for the long-term benefit of the group. How such delayed selection actually takes effect is still imperfectly understood; and because it involves long time-scales our only hope of investigating it is in ecosystems that have lain long undisturbed, for centuries at least, and dynamic equilibria established. Increasingly, such conditions are becoming confined to nature reserves in old-established stable ecosystems. Really primeval ecosystems have been and are being severely diminished in extent, most seriously of all in the species-rich tropical zone. The retention of adequate samples of them as reserves is of great importance to science, for reasons of which this is but one illustration.