Fungi Explain Rainforest Diversity, “Police” The Growth And Spread Of Dominant Species
Fungi, often recognized as pests, may play a critical role in rainforests worldwide, according to a new study. According to research out of Oxford University, fungi check the growth and dominance of closely packed plant species by spreading quickly among them, allowing a wider range of species to prosper. The study, funded by the Natural Environment Research Council (NERC) will be published in Nature.
Like Us on Facebook
"In the plant world, close relatives make bad neighbors," said Dr. Owen Lewis, lead author of the study, in a press release. This research reveals why seedlings growing near plants of same species are more likely to die than seedlings of other plant species. Earlier, it was thought that there was something in soil responsible, but now it is known that fungi play a critical role. The study, according to Lewis, demonstrated the profound impact microscopic fungi may have on rain forests.
The researchers conducted their study in 36 sampling stations across the Chiquibul Forest Reserve in Belize. They sprayed the plots with water and insecticide or fungicide every week over a period of 17 months. The researchers found that insecticide did not make as much of an impact on the number of species as fungicide did.
The use of fungicide Amistar® reduced the effective number of species by 16 percent; the insecticide on the other hand, merely changed the composition of surviving species without significantly impacting their diversity.
In other words, the researchers found that fungi can easily spread across plants and seedlings of the same species, preventing the dominance of any one species. When plots were sprayed with fungicide, it was observed that diversity dropped markedly while only a few species grew at the expense of others.
According to study co-author, Dr. Rob Freckleton of Sheffield University, the team expected that removing both fungi and insects would impact the trees, but the removal of the fungi alone led to diversity which was unexpected. The elimination of insects, on the contrary did not make a difference to diversity. "Ours is the first study to unpick the effects of the different natural enemies," Freckleton said.
The scientists also expected that oomycytes, fungus-like microorganisms that were responsible for the potato famines in 1840s, played a role in determining rainforest diversity. To test this theory, the scientists sprayed the plots with a checmical called Ridomil Gold® that kills this pathogen, but found no significant impact on surviving plants. They believe that this shows that fungi are the true driver of rainforest diversity, not oomycetes.
The study also explains why tropical rainforests, where fungi can thrive in wetter, hotter areas, have greater diversity in comparison to forests in temperate region. In addition, it could be significant from the perspective of climate change, which is "predicted to reduce overall rainfall making it harder for fungi to spread. Without fungi to keep species in check, we could see a significant knock-on effect and lose a lot of the diversity that makes rainforests so special," said Dr. Robert Bagchi, one of the authors of the study.
Photo above courtesy of Shutterstock.
© 2012 iScience Times All rights reserved. Do not reproduce without permission.