Forest palms producing smaller seeds in Brazilian rainforest

Human activity in and around parts of Brazil's tropical forests has driven away many of the area's fruit-eating birds, according to researchers. Courtesy: CIAT/Flickr

Tuesday, June 4, 2013, 5:34 PM -

Fruit-eating birds are disappearing from Brazil's tropical forests, causing palms to produce smaller, and less efficient, seeds.

Human activity in and around parts of Brazil's tropical forests has driven away many of the area's fruit-eating birds, prompting palms to start producing smaller, less successful seeds.

Researchers say this trend has been evolving since coffee and sugar cane development began in the region in the 1800s.

An international team of researchers collected more than 9,000 seeds from 22 types of regional palms and compared their findings with genetic and statistical data.

Researchers believe the smaller seeds have evolved due to the absence of seed-dispersing birds.

"Unfortunately, the effect we document in our work is probably not an isolated case," said lead author Mauro Galetti at a press briefing.

"The pervasive, fast-paced extirpation of large vertebrates in their natural habitats is very likely causing unprecedented changes in the evolutionary trajectories of many tropical species." 

While many studies focus on the impact of climate change, researchers say this is one of the first studies to analyze the impact of human activity in Brazil's forests.

"Habitat loss and species extinction is causing drastic changes in the composition and structure of ecosystems, because critical ecological interactions are being lost," Galetti said. 

"This involves the loss of key ecosystem functions that can determine evolutionary changes much faster than we anticipated. Our work highlights the importance of identifying these key functions to quickly diagnose the functional collapse of ecosystems."

The complete study can be found in the May 31 issue of Science.