Thieving rodents move big seeds

Wooly mammoths may be extinct, but the plants that once fed these large animals persist thanks to seed dispersal via rodent thievery, researchers find. Seed dispersal helps plants adapt to environmental change, but modern animals cannot ingest and defecate the large seeds that were once consumed by now-extinct giant mammals. To determine if scatter-hoarding rodents helped large-seeded plant species persist for more than 10,000 years, Patrick Jansen and colleagues used radio telemetry and motion-sensitive cameras to investigate the seed dispersal of palm trees by rodents called agoutis. The researchers placed radio-tagged seeds across Barro Colorado Island, Panama, and set up camera traps to determine which animals moved the tagged seeds. Though the rodents are generally not considered effective seed dispersers, the researchers found that one third of the seeds traveled farther than an established threshold for long-distance seed dispersal, and that 13% of the seeds survived until the following year, almost exclusively due to agouti hoarding. The rodents initially moved the seeds short distances, but over the course of a year, the agoutis stole and re-cached others' seeds up to 36 times, eventually transporting the seeds great distances. According to the authors, these results suggest that large-seeded plants have a long history of seed dispersal by rodents.

Article #12-05184: "Thieving rodents as substitute dispersers of megafaunal seeds," by Patrick A. Jansen, Ben T. Hirsch, Willem-Jan Emsens, Veronica Zamora-Gutierrez, Martin Wikelski, and Roland Kays

MEDIA CONTACT: Patrick A. Jansen, Wageningen University, Wageningen, THE NETHERLANDS; tel: +31-317-486-197; e-mail: patrick.jansen@wur.nl