All about being connected
"We did not predict this," Damschen said. "In hindsight, this makes a lot of sense. Wind can be channeled between physical structures. For example, think of when wind speeds up as you walk between tall buildings in a city. Corridors may similarly funnel wind and carry seeds down them. We are now testing for this kind of effect. My postdoc, Dirk Baker, and our technician, Colin Kremer, are using a model of wind dispersal in patchy landscapes to predict where these seeds might go based on wind dynamics. We then determine if the model accurately predicts where seeds go by releasing artificial seeds that literally glow in the dark. We release them into the wind and then find them again at night with a black light. We can record where the seeds go by using a GPS and match what is happening in reality to the model's predictions."
For unassisted species, the researchers predicted that corridors would have no effect because they assumed that their seeds were dropped near the parent plant, traveling no more than a few meters a year. Therein was the surprise.
"We found a really strong response to corridors, contrary to what we expected," Damschen said. ""We think these plants must be being assisted in some way, and we think it's possibly from mammals. Unassisted plants exceeded our expectations by a long shot."
Other studies suggest that some mammals incidentally ingest seeds while foraging, so perhaps they are providing assistance.
In order to find out if this is a plausible explanation, Caleb Hickman, a graduate student in the WUSTL Ecology, Evolution, and Population Biology Program, has collected fecal samples from a variety of mammals at the experimental sites and is literally planting them in soil in the WUSTL greenhouse to see if plant species emerge as seedlings that woul
|Contact: Ellen Damschen|
Washington University in St. Louis