Study shows forest diversity promotes productivity

October 13, 2016

Biologically diverse forests are productive forests, according to a new study co-authored by a team of scholars from 90 institutions worldwide.

The study, which was published this week in the journal Science, showed that when the number of tree species in a given forest increases, so does the forest productivity in terms of wood production. The opposite was also true: A decline in biodiversity would result in an accelerating decline in forest productivity.

The findings could offer important guidance for forest managers across the globe.

“It tells us that it’s important to conserve biodiversity in these forests,” said co-author David McGuire, a researcher at the University of Alaska Fairbanks. “What this paper is saying is that the rate at which wood and fiber is produced by these forests will be higher if we maintain more diverse forests.”

McGuire, who is part of the Alaska Cooperative Fish and Wildlife Research Unit at the UAF Institute of Arctic Biology and the U.S. Geological Survey, was one of the co-authors of the paper, which was coordinated by the Global Forest Biodiversity Initiative and West Virginia University. David Verbyla of the UAF School of Natural Resources and Extension was another co-author.

McGuire noted that the availability of things like water, light and nutrients varies throughout a forest. For example, he said, some plants and trees might grow best in dry parts of the forest, while others grow best with more moisture. In a diverse forest, each species grows in an area best suited for its needs, resulting in more of the trees and plants being healthier and more productive than in a less diverse forest.

“It makes a lot of sense that certain species can better occupy certain environments in a forest. Because of that, it also makes sense that more diverse forests make better use of the available resources than less diverse forests” McGuire said. “However, this idea has only been tested at local scales. The value of this study is that we were able to test whether this idea held for forests throughout the globe.”

The relationship between increased biodiversity and increased production in forests was documented to be a universal relationship worldwide. The team gathered data from nearly 800,000 research plots worldwide in all major global forest ecosystems across 44 countries and territories.

“We are very fortunate to have worked with so many dedicated foresters and researchers on this study,” said WVU’s Jingjing Liang, lead author of the paper. “This team by itself shows that diversity can bring forth great productivity in scientific collaboration.”

After analyzing the data, researchers determined that loss of tree species richness — through deforestation, forest degradation and climate change — would accelerate the decline in forest productivity worldwide.

Researchers estimated that if diversity declined to one species per forest, commercial forest productivity across the world would decline by up to 66 percent. That would hold true even if other things, including the total number of trees, remained the same, they said.

The study found that the corresponding economic value of that loss would be up to $500 billion per year worldwide. That is more than double what it would cost to implement effective conservation for all of Earth’s forest ecosystems on a global scale.

In addition to the financial benefits of biological conservation, the study found that species richness in forests provides many social, ecological and environmental benefits, including climate regulation, animal habitat, water-flow regulation and genetic resources.

ADDITIONAL CONTACTS: David McGuire, admcguire@alaska.edu. David Verbyla, dlverbyla@alaska.edu.

NOTE TO EDITORS: McGuire will have sporadic phone contact this week. Please email him to set up an interview time.

ON THE WEB:
Global Forest Biodiversity Initiative, http://www.gfbinitiative.org/
MinuteEarth video about the research findings: http://www.minuteearth.com/biodiversity