Genetically Engineered Organisms and Exotic Species

In 1987, a report by the National Academy of Sciences stated " an urgent need for the scientific community to provide guidance to both investigators and regulators in evaluating planned introductions of modified organisms from an ecological perspective " (39). This chapter incorporates such a perspective and focuses on a number of ecological issues relevant to the planned introduction of genetically engineered organisms into the environment. The major concern associated with planned introductions stems from the potential for problematic ecological effects that are unintended or unforeseen. With appropriate regulatory oversight, such effects are unlikely to follow from any planned introductions in the near future. If they occurred, however, they might be felt at any level—from the local population, through the community and ecosystem, to fundamental ecological processes —although the probability of such disruptions decreases as their severity increases. A number of ecological questions are explored in this chapter, including the relevance of experience with introduced exotic organisms, the types of disruptions to natural populations that could take place, and the potential for effects on ecosystem processes of energy flow and nutrient cycling. Review of the data bearing on these questions suggests that there is some reason to be cautious, but no cause for alarm at the prospects of planned introductions of genetically engineered organisms into the environment. Studies of biogeography–the distributions of plants and animals-demonstrate the presence in most modern environments of nonnative or exotic organisms that evolved elsewhere. The number of these exotic species (microbes, plants, and animals) is large, as a result both of natural processes of dispersal and deliberate and accidental distribution aided by humans. No good data indicate what proportion of introduced organisms has created ecological problems, although it is generally agreed to be small. Some scientists believe that experience with exotic species provides an example of what might be expected from genetically engineered organisms in planned introductions, and that " the history of introductions is a history of disasters that should not be forgotten lest it be repeated " (23). Others argue that the best guide is the experience with past introductions in agriculture of organisms produced by hybridization and crossbreeding—a history of far more positive results, and one in which negative consequences have been met with a variety of existing control and mitigation strategies. They point out that all major crops in the United States are exotic species introduced from other regions of the …