Sunday, July 26, 2015

Global study of seed consumption uncovers wider risk to plant species

Deborah Smith in the University of New South Wales Newsroom: The first worldwide study of animals and the seeds they eat has overturned a long-held assumption – that large animals mainly eat large seeds. The finding by UNSW Australia scientists has implications for conservation showing that a wider variety of plants than is often thought could be at risk if large animals go extinct and do not disperse their seeds.

In a comprehensive study, UNSW’s Si-Chong Chen and Professor Angela Moles compiled and analysed data on more than 13,000 animal-seed interactions, based on previously published reports. “It is the first broad-scale study of the relationship between animal body mass and ingested seed size ever undertaken,” says Ms Chen, a PhD candidate in the UNSW School of Biological, Earth and Environmental Sciences.

“We covered all vertebrate groups – fish, amphibians, reptiles, birds and mammals. And we included animals from many different areas – from the Arctic tundra to the tropical rainforests.”...The smallest seeds in the study were the tiny seeds of the mountain snowberry, and they were eaten by the smallest animals in the study – skinks on the Chatham Islands near New Zealand. The largest seeds were the 9-centimetre long seeds of the African tropical forest tree, Balanites wilsonia. They were eaten by the largest animals in the study – 4-tonne African elephants.

“It has long been predicted that as the body size of animals increases so does the size of the seeds they ingest,” says Ms Chen. “Big animals do eat some big seeds from fleshy fruits. But the prediction is wrong because it overlooks the fact that big animals like buffalos, cows, deer and zebras also accidentally vacuum up hundreds of small seeds as they graze on short grassy vegetation.”...

Sunflower with bee, shot by Rasbak, Wikimedia Commons, under the Creative Commons Attribution- Share Alike 3.0 Unported license 

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