An insidious threat to tropical forests: over-hunting endangers tree species in Asia and Africa
April 04, 2013
A fruit falls to the floor in a rainforest. It waits. And waits. Inside the fruit is a seed, and like most seeds in tropical forests, this one needs an animal—a good-sized animal—to move it to a new place where it can germinate and grow. But it may be waiting in vain. Hunting and poaching has decimated many mammal and bird populations across the tropics, and according to two new studies the loss of these important seed-dispersers are imperiling the very nature of rainforests.
“Animals that eat fruit and disperse seeds are particularly sensitive to hunting. So in hunted forests often you find that there are few animals that can disperse seeds, particularly the largest seeds,” Rhett Harrison with the Chinese Academy of Sciences told mongabay.com. Monitoring a protected forest in Borneo for over 15 years, Harrison and his team have found that over-hunting has led to “pervasive changes” in tree populations “leading to a consistent decline in local tree diversity over time,” according to their study published in Ecology Letters.
Ola Olsson with Lund University found a very similar situation thousands of miles away in Nigeria. Comparing non-hunted sites with hunted sites (where most primates including gorillas had vanished), Olsson and other researchers found that seedling populations—i.e. future trees—were vastly different in a new paper in the Proceedings of the Royal Society B.
“The changed composition among seedlings that we see now will lead to a future tree composition which is different from the present, with fewer large-seeded fruiting trees and more wind dispersed species,” Olsson says.
Although conservationists have long warned about the impacts of deforestation and climate change in the tropics, over-hunting also poses another still largely hidden problem. Scientists are still trying to work out the overall ramifications, but ultimately this “empty forest” trend will lead to less biodiversity and drastically different rainforests even in so-called protected areas.
The long article, with many photos, continues here.
- Hunting for meat impacts on rainforest (eurekalert.org)
- Bushmeat Trade Is Transforming Rain Forest (livescience.com)
- Brazil to count every tree in its rainforests in massive census (treehugger.com)
- Functional redundancy and complementarities of seed dispersal by the last neotropical megafrugivores (scicombinator.com)
- Dr. Reese Halter: Rapacious War Against Nature: Indonesian Palm Oil (huffingtonpost.com)