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The ecological and evolutionary aspects of planned introductions of transgenic organisms into the environment are considered in this report. The authors support the timely development of environmentally sound products, such as improved agricultural varieties, fertilizers, pest control agents, and microorganisms for waste treatment, through the use of advanced biotechnology within the context of a scientifically based regulatory policy that encourages innovation without compromising sound environmental management. Economic, social, and ethical concerns also must be weighed along with strictly ecological and evolutionary considerations, but these other issues are beyond the scope of this report. Ecological oversight of planned introductions should be directed at promoting effectiveness while guarding against potential problems. The diversity of organisms that will be modified, functions that will be engineered, and environments that will receive altered organisms makes ecological risk evaluation complex. While we cannot now recommend the complete exemption of specific organisms or traits from regulatory oversight, we support and will continue to assist in the development of methods for scaling the level of oversight needed for individual cases according to objective, scientific criteria, with a goal of minimizing unnecessary regulatory burdens. In this report, we provide a preliminary set of specific criteria for the scaling of regulatory oversight. Genetically engineered organisms should be evaluated and regulated according to their biological properties (phenotypes), rather than according to the genetic techniques used to produce them. Nonetheless, because many novel combinations of properties can be achieved only by molecular and cellular techniques, products of these techniques may often be subjected to greater scrutiny than the products of traditional techniques. Although the capability to produce precise genetic alterations increases confidence that unintended changes in the genome have not occurred, precise genetic characterization does not ensure that all ecologically important aspects of the phenotype can be predicted for the environments into which an organism will be introduced. Many important scientific issues must be considered in evaluating the potential ecological consequences of the planned introduction of genetically engineered organisms into the environment. These include survival and reproduction of the introduced organism, interactions with other organisms in the environment, and effects of the introduced organism on ecosystem function. We encourage the use of small—scale field tests , when justified by previous laboratory and/or greenhouse studies, under conditions that minimize dispersal and under appropriate regulatory oversight. As the biotechnology industry develops, continuing regulatory oversight as well as long—term research and monitoring will be necessary for responsible risk management. Many engineered organisms will probably be less fit than the parent organism, although some importan...

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Birds and mammals are important seed dispersers and their diversification in the Cretaceous may have created niches for many plant specialists on scattered resources. Maintaining sexual recombination through wind pollination in such sparse populations is difficult, and so angiosperms with their sophisticated systems for insect pollination were favored in many critical situations.

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Documentation is reported for sea turtles overwintering on the sea bottom. Seri Indians have traditionally hunted nonmigrating dormant green turtles (Chelonia mydas) along the bottom of the Infiernillo Channel in the Gulf of California. Mexican fishermen independently discovered dormant turtles during winter 1972-1973, and with new hunting technologies are rapidly decimating these unusual stocks.

Simpson (1964) observed that there are fewer species of mammals present at the tips of all the major North American peninsulas than at their bases, a pattern that has subsequently been found to apply to other vertebrate groups. Cook (1969) documented its existence in birds; Kiester (1971) found it to hold for amphibians and reptiles on Florida. This pattern of diversity (sensu "species richness" or "species density") is neither coincidental nor transient, according to Simpson; it is an equilibrium resulting from the peculiarities of peninsular geometry. The implications of this suggestion are intriguing inasmuch as peninsulas are common, not only the terrestrial form in bodies of water but also peninsulas of suitable habitat extending into hostile environments. We propose in this paper to begin looking in detail at the nature of Simpson's "peninsular effect," its roots and its implications. Before the peninsular effect is used as an explanation for existing patterns (e.g., Willis 1974), its cause should be clear. Does it indeed reflect a general property of peninsular geometry, or does it merely reflect peculiarities of the North American sites for which we have data? For example, paleoecological data for Florida published since Simpson's paper appeared (Watts 1971) demonstrate that the vegetation on that peninsula is undergoing systematic changes quite apart from man's disturbances. The xeric vegetation of 5,000 yr ago has become more mesic, primarily as a result of a continuing rise in the water table. One can only speculate on the likelihood of faunal equilibria in the face of floristic instability, but the possibility remains that modern diversity patterns of vertebrates on Florida are not stable and do not therefore necessarily represent an equilibrium effect. Nor, unfortunately, are the patterns on Alaska and Labrador unambiguous; both peninsulas have few species and harsh climatic gradients along their lengths. Elimination of Florida, Alaska, and Labrador leaves only two major sites where Simpson's hypothesis can be pursued: Yucatan and Baja California. The decrease in diversity on Yucatan is difficult to evaluate. The fauna are not well known, and Simpson's data base (Hall and Kelson 1959) is certainly incorrect (Birney et al. 1974). Compounding this uncertainty is the fact that there are striking changes in topography and vegetation from Guatemala northward. If Yucatan is excluded, then Baja California is the only remaining major North American peninsula the diversity profile of which is adequately known and suggests a peninsular effect. Are biogeographic patterns on Baja California in equilibrium or not? It looks as if they are. The peninsula has been stable geologically since the early Pliocene, with a configuration similar to that of today (Durham and Allison 1960), though the Gulf of California has widened substantially in the last 4 million yr (Larson et al. 1968). Apparently the only recent geological change of importance was siltation by the