Thirteenth report : the release of genetically engineered organisms to the environment / Royal Commission on Environmental Pollution ; Chairman Lord Lewis of Newnham.

  • Great Britain. Royal Commission on Environmental Pollution
Date:
1989
Catalogue details

Licence: Open Government Licence

Credit: Thirteenth report : the release of genetically engineered organisms to the environment / Royal Commission on Environmental Pollution ; Chairman Lord Lewis of Newnham. Source: Wellcome Collection.

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    RABBITS AND MYXOMATOSIS 1. The introduction and spread of the Myxoma virus in the UK had many indirect environmental effects because rabbit populations interact strongly with their food plants. The removal of rabbits markedly changed the structure and composition of vegetation, with a wide variety of effects on other species. Some of the examples are anecdotal but serve to illustrate the kind of complex and unexpected things that can happen. As grassland sward became taller and thicker, ant populations declined. These ants are important prey for green woodpeckers, and a decline in green woodpecker numbers has been attributed, at least in part, to the effects of removing rabbits(*°). It is not known whether any prey of green woodpeckers such as woodboring beetles then increased but it is possible that some did. It would not have been easy, prior to the release of Myxoma virus in Britain, to predict the consequences for woodpeckers or indeed for the wood-boring beetles. 2. Better documented examples include the decline of open country or heathland species of high conservation importance, such as stone curlews and the large blue butterfly, in both cases attributable at least in part to changes in the vegetation. As rabbit populations collapsed predators, such as buzzards and foxes, turned to alternative prey, for example mice and voles. The indirect effects on other organisms of this increased predation on rodents is unknown. In woodlands, due to the lack of rabbits, sycamore seedlings survived in unprecedented numbers. The first few years after the introduction of the Myxoma virus saw a whole generation of this introduced tree dominating in woodland glades and shading out the existing plants. Traditionally bred plants and animals 4.24 As noted in Chapter 2, cultivated plants and domesticated animals have been bred for centuries in order to improve their value to man and have been introduced widely into the environment. Some GEOs may be expected to have similar impacts on the environment to those produced by new varieties of traditionally bred crops and ornamental plants. In breeding programmes in agriculture and floriculture large numbers of progeny from sexual crosses are released in field trials for evaluation. The diversity of types in these progeny is often enormous, but most of the offspring are unsuitable for use in commercial agriculture and horticulture. When a successful plant has been selected its seed is multiplied and ultimately is made available for sale. If a new cultivar of acommercial crop is highly successful it will be grown on large acreages. This routine practice obviously has significant effects on the environment. 4.25. Many traditionally bred genetic variants released into agriculture are chosen because they have genes improving resistance to pests or pathogens by comparison with the cultivars they are intended to replace. Such effects will also be the desired aim with many genetically engineered crop plants. When resistant varieties are adopted by the industry they are expected to have significant impacts on local population dynamics among other organisms in the environment, namely, the pests and pathogens to which they are resistant. In general, however, the animals or plants produced by conventional breeding techniques are not perceived by the public as a threat to the environment. Ferals and weeds 4.26 Many domesticated animals and crop plants cannot survive for long without man’s intervention. Some domesticated animals have, however,
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