One of the most serious and least understood threats to the world's ecosystems is the problem of invasive species-exotic plants, animals and other organisms that are brought into habitats and subsequently spread at a rapid rate, often replacing native species and reducing biodiversity.

Invaders thrive best in regions where there is an abundance of materials for growth, such as water, nutrients and light. Biologists have long assumed that alien species pose less of a threat in resource-poor environments because they are less able to compete with indigenous plants, which have adapted to their habitats over thousands of years. But a new study by Stanford University researchers finds that invasive plants can flourish in low-resource environments by adopting efficient ways to use available resources.

The finding, which sheds new light on how invaders achieve success, may change the way scientists think about invasive species and how to curb them, according the authors of the study published in the April 26 issue of the journal Nature.

"What was very intriguing to us is that there are invasive species that are capable of invading low-resource systems," said Jennifer Funk, a postdoctoral fellow in the Stanford Department of Biological Sciences and lead author of the study. "Typically people think low-resource systems aren't invasible. People think of the native plants as having a home-field advantage, because they evolved there."

Smart plant growth

Plants depend on sunlight, nutrients and water to survive, and a shortage of any one of these will restrict how fast they can grow. When plants use these inputs more efficiently, however, they can photosynthesize-and thus grow and spread-faster, according to Funk and Vitousek.

To compare the resource-use efficiencies of alien and native plants, the researchers studied three ecosystems in Hawaii-a forested area with limited light, volcanic soils with low nutrie
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Contact: Mark Shwartz
mshwartz@stanford.edu
650-723-9296
Stanford University
1-May-2007