Primates are Critical for Seed Dispersal in Tropical Forests

Primates may be key when it comes to revitalizing tropical forests. Scientists have taken a closer look at seed dispersal and have discovered that primates are crucial when it comes to spreading seeds and ensuring that they grow.

In order to better understand seed dispersal, the researchers studied how feed, sleeping and ranging habits of two species of New World monkeys affected the dispersal of a Neotropical legume tree. More specifically, the scientists monitored a group of Brown-mantled tamarins and Moustached tamarins. Fruits from the studied trees were pods that contained 16 to 23 seeds, each of which was surrounded by edible gum. The monkeys fed on the gum while swallowing the seeds.

"With the help of genetic analyses of the DNA found in the seed coat, which is of maternal origin, we could make an exact assignment of the corresponding 'mother tree' for the seeds," said Eckhard Heymann, one of the researchers, in a news release. "This allowed us to determine how far Parkia seeds were dispersed by the monkeys. With the help of analysis from microsatellites, short repeated DNA sequences, we were able to identify genetic similarities of individual trees."

In the end, the researchers found that there was a significant genetic relationship of the plant embryos and the young trees within a radius of 300 meters. This, in particular, coincided with the distance within which most seeds were dispersed by the tamarins.

"In tropical forests, the seeds of 80 to 90 percent of trees and lianas are dispersed by animals," said Heymann. "In addition to primates, birds and bats are the major animal groups that are responsible for the seed dispersal. For the plants, transport of their seeds is extremely important. As sedentary organisms, this is the only way that their offspring-the embryos contained in the seeds-can reach appropriate sites for germination and growth."

The findings are published in the journal Trees.