March 15, 2011
A group of international scientists, including a University of Guelph biologist, are studying some introduced species that dominate new habitats when native plants should technically have the advantage.

The findings were published in the journal Ecology Letters.

University of Guelph researcher Andrew MacDougall said, “Biological invasions are one of the planet’s greatest threats to biodiversity and ecosystem services. Invasive plant species present a serious environmental, economic and social problem worldwide.”

Despite substantial research, scientists know little about why some species dominate new habitats, when native plants should technically have the advantage.

A common, but rarely tested assumption, is that some special behaviour enables these plants to become more abundant in their new homes than in their native communities. “If true, then biosecurity screening procedures should focus on how introduced species behave,” explained MacDougall.

Scientists involved in this global collaboration are termed the Nutrient Network, which includes MacDougall’s lab. The group has spent three years collecting data for 26 plant species at 39 locations on four continents. What the scientists found was that what is known as the abundance assumption did not hold for the majority of plant species. Twenty of the 26 species were equally, or less abundant at both new and native sites.

“Instead, abundance at native sites can predict abundance at introduced sites, a criterion not currently included in biosecurity screening programs,” said Jennifer Firn of Queensland University of Technology, the study’s lead author Thirty-six other scientists were involved in the research.

“Predicting success of invading species is difficult and uncertain but very important,” said Henry Gholz, program director in the National Science Foundation’s division of environmental biology, which funds the Nutrient Network.