Climate change and 'Alien Species in National Parks': revisited.

Abstract

Abstract Many units comprising the National Park Service system in the USA were established to protect native species and historical landscapes and scenery, and to provide public enjoyment of the same, as long as the natural area remained 'unimpaired for future generations'. However, a growing human population and a global economy have spawned a 40-fold increase in global trade and transportation since 1950. This created what may turn out to be the most significant challenge to Park Service management: the invasion of alien (i.e. exotic, non-native) plants, animals and diseases into 'protected areas'. Climate change may compound the problem by interacting with other existing ecosystem stressors to affect the distribution, abundance and impact of invasive species. Scientists' warnings have not been entirely ignored, but harmful invasions may be outpacing effective managerial responses. This chapter revisits a paper published in 1995 by D.B. Houston and E.G. Schreiner entitled 'Alien Species in National Parks: Drawing Lines in Space and Time', to demonstrate that despite efforts to contain alien plants, animals and diseases, the number and abundance of conspicuous invaders may be increasing. New and spreading alien species are directly affecting native species abundance, their genetic integrity and the management of adjacent lands, and human health. While climate change may add an additional or interacting threat to park resources, we found that at park scales and over short periods (17 years in this case), it has become increasingly difficult to achieve the primary mission of the National Park Service, for example protecting native species and ecosystems for present and future generations, due to the continuing invasions of alien organisms largely resulting from increased trade and transportation.