"The design and scale of this study are remarkable," said Orrock. 'Nothing has been done like this for plants before. It's the largest, best-replicated study of corridors in the world. "
"We knew coming into this study that corridors work, but we wanted to predict how they work for species, based on simple life history traits that are readily available," said Damschen, who painstakingly counted 300 different plant species that have occupied the patches since 2000 when the research began. "One of the important things we show is not only how a corridor works and affects a community of species in a single year or a few years, but how they work over much longer time scales."
In general, the researchers found that, overall, there were more species in the patch connected by a corridor than the unconnected ones. But they predicted that groups of species would respond differently depending on how they were moved around the landscape. Seeds are dispersed by wind, birds, or they move almost imperceptibly, dropping a few inches away from the parent plant, and thus are called unassisted.
Damschen can tell the source of dispersal by seed type. Wind-dispersed plants have a fuzzy feature, like a dandelion, called a pappus; bird-dispersed plants have fleshy fruits, and unassisted plants have plain, dull, little round seeds, similar to poppy seeds.
For birds, the researchers had great predictive power. There were more bird-dispersed species in the connected then in either the unconnected rectangle or winged patches, which was the result of a detailed understanding of how birds move and forage.
For wind-dispersed plants, the researchers predicted that patch shape an increase in habitat edges relative to cores would increase the number of species in the community.
|Contact: Ellen Damschen|
Washington University in St. Louis