Unpredictable Invasions

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Science  21 Dec 2001:
Vol. 294, Issue 5551, pp. 2433
DOI: 10.1126/science.294.5551.2433a

When Europeans settled in New Zealand in the late 18th century, they brought with them browsing mammals, notably goat and deer, and thereby initiated a long-term experiment on the effects of introducing an alien life form on the ecology of native forests. Wardle et al. examined how the introduced browsers influenced below-ground and litter-layer biodiversity and ecosystem processes, comparing browsed forest with exclosures set up 25 to 50 years ago. There were consistently adverse effects on particular elements of the forest community, especially populations of indigenous plants and litter-dwelling fauna. Nevertheless, the survey revealed a mosaic of browser effects, with soil biodiversity and soil nutrient dynamics being affected differently in different locations and in idiosyncratic ways. This unpredictability highlights the importance of preventing the establishment of alien species.—AMS

Ecol. Monogr.71, 587 (2001).

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