Deforestation in the Amazon rainforest affects the diversity of microbial communities, finds a new study.

A team of international researchers studied about 38 square miles in the Fazenda Nova Vida site near Rondônia, Brazil, for the last four years. This is a location where rainforest has been converted for agricultural use.

It is known that deforestation in the Amazon affects the diversity of plants and animals, but the new study has found that there is a net loss in diversity among microbes. This is a major concern, as microbes play a significant role in the functioning of the ecosystem.

"We have known for a long time that conversion of rainforest land in the Amazon for agriculture results in a loss of biodiversity in plants and animals. Now we know that microbial communities which are so important to the ecosystem also suffer significant losses," lead author of the study Jorge Rodrigues, a biologist at the University of Texas at Arlington, said in a statement.

The new study is in terms with earlier findings suggesting that the microbes in soil became diverse over the years, as the soil was converted to pasture for agricultural use. But the loss of restricted ranges for certain microbes has resulted in the net loss of diversity overall, suggesting that human-caused changes in the environment are affecting the microbes.

When the research team compared the microbes thriving in forest soil with those in pastures, they found that the number of microbes was higher in pastures, but they were less related to each other.

While earlier studies have suggested that the diversity of microbial communities would have a positive response to environmental changes, this new study agrees that it is true in a small scale. But on a larger spatial scale, land use leads to a net decrease in diverse microbes, researchers said.

The research team is currently working to find if microbial diversity could be recovered in case the pasture lands are turned into secondary forest.

The findings of the study, "Conversion of the Amazon rainforest to agriculture results in biotic homogenization of soil bacterial communities", will appear online this week in the journal of Proceedings of the National Academy of Sciences.