Scientist Jon Chase once worked in a lab that set up small pond ecosystems for experiments on species interactions and food webs.
"We would try to duplicate pond communities with a given experimental treatment," he says.
"We put 10 of this species in each pond, and five of these species, and eight of the other species, and 15 milliliters of this nutrient and 5 grams of that and 'sproing,' every replicate would do its own thing and nothing would be like anything else.
"That made me curious. What if, instead of trying to eliminate the messiness, I tried to figure out where it was coming from?"
The results of that investigation are published online this week in Science Express. A seven-year experiment isolated one reason experimental ponds go wild: history.
If a pond has enough nutrients, the pond community that emerges depends on the order in which species were introduced, says Chase, an ecologist at Washington University in St. Louis.
The discovery has broad implications for highly productive ecosystems such as tropical rainforests and coral reefs, and for attempts to restore these ecosystems.
Restoration can fail if the original ecosystem bears the imprint or memory of its past in ways that are not understood.
"This study is an important experimental confirmation of the influence of primary productivity on regional biodiversity," says Alan Tessier, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.
"The findings have broader relevance to the protection and restoration of biodiversity."
In the summer of 2002, Chase embarked on the long-term pond experiment at the Tyson Research Center, a 2,000-acre field station on the outskirts of St. Louis, and owned by Washington University.
He set out 45 cattle tanks in an old field, added dirt to each and filled them with well water.
|Contact: Cheryl Dybas|
National Science Foundation