Introduced plants in the high altitude environments of Kosciusko National Park, South-Eastern Australia

Abstract

Until recently, most of the available research on the biology of introduced plant species, their interactions with neighbouring species and their responses to a range of environmental conditions has been carried out in an agricultural context. However, the study of introduced plants in natural areas has received increasing attention in the last decade, including the initiation in mid-1982 of a wide-ranging SCOPE programme (Scientific Committee on Problems of the Environment, a subsidiary body of the International Council of Scientific Unions) on the Ecology of Biological Invasions. The research associated with the SCOPE programme has now been published as a series of regional and global reviews (Groves & Burdon, 1986; Kornberg & Williamson, 1986; Macdonald et al., 1986; Mooney & Drake, 1986: Joenje et al., 1987; Usher et al., 1988; Drake et al., 1989). Particular emphasis in these and other studies has been given to factors contributing to the successful establishment of introduced species, and the susceptibility of different communities and ecosystems to introduced species invasions. Natural and semi-natural areas (those areas which are relatively undisturbed by human activities) in most countries are becoming fewer and smaller, and those that remain are subject to increasing visitor use and exploitation. The current concern about the effects of introduced species in natural areas is related to the growing scientific and public awareness of the value of natural areas and their component species. An introduced species is defined in a natural area context as any species which is not native to the region being studied. There are few ecosystems in the world which have not been affected by introduced plant invasions (Usher, 1988; Heywood, 1989). Most of these invasions can be linked either directly or indirectly with human activities, with invasion of undisturbed ecosystems being extremely uncommon (Johnson, 1982; Fox, 1988). Introduced species invading both natural and modified ecosystems vary greatly in their ability to colonise and persist at a site, in their rates of spread and in their effects on the existing plant communities and ecosystem processes (Forcella, 1985; Christensen & Burrows, 1986; Heywood, 1989). Even among the most successful invaders, such as Chrysanthemoides monilifera in coastal areas of southeastern Australia (Weiss & Noble, 1984a & b); Acacia saligna, A. cyclops and A. longifolia in the fynbos biome of southern Africa (Macdonald & Jarman, 1984; Macdonald et al., 1989) and Hypericum perforatum in temperate grassland and woodland communities (Groves, 1989); there appear to be few attributes common to all species which can be used to accurately predict the invasion potential of individual species (Healy, 1969, 1973; Crawley, 1986, 1989; Newsome & Noble, 1986; Williamson & Brown, 1986; Esler, 1988; Noble, 1989). Show more