Historical forest biodiversity changes conservation efforts
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LANSING -- A recent study uncovers the changes within historical tree biodiversity hotspots in Michigan and elsewhere in the Midwest, with implications for new conservation efforts in forested areas of concern.
"When we think about biodiversity hotspots, these are areas that have a lot of species that are on the landscape. We tend to emphasize them as areas of concern and put preserves on those areas," said Carolyn Copenheaver, the study's author and a professor of forest ecology at Virginia Tech.
Historical forest biodiversity hotspots indicate the current state of species richness of trees in a particular area.
"If we find that a historical biodiversity hotspot is currently in an urban area, we've lost all of those species," said Copenheaver.
"However, if we find that a historical biodiversity hotspot is in a national forest, national park, state forest or state park, that means that we have the potential to preserve that area that has historically been a biodiversity hotspot," she said.
Copenheaver used public land survey records from the General Land Office to reconstruct historical biodiversity hotspots. A map in the data set for Michigan is Circa 1800 Vegetation, which is a beacon for numerous forest management and restoration projects.
"This map has been a guiding light to many entities, including private organizations and the state who have used it in guiding their state forest management and restoration efforts in grasslands and all ecosystems," said Doug Pearsall, a senior conservation scientist for the Nature Conservancy.
Findings of the study found little difference in historical forest biodiversity and present-day biodiversity in states such as Indiana, Ohio and Illinois. However, in states such as Michigan, Iowa, Missouri, Minnesota and Wisconsin, lands show significant differences in historical biodiversity and present-day land use.
Michael Belitz, a postdoctoral research fellow at Michigan State University and an incoming faculty member at the University of Wisconsin-Madison, notes how in states such as Missouri and Minnesota, there is a higher species richness that was preserved from the past on federal and tribal lands.
"Historical hotspots that are on tribal land and federal lands are more likely to be conserved as is," Belitz said. "However, urban areas and townships could be vulnerable to losing species richness unless there are very specific urban conservation and urban forestry practices that are taken into account."
To the contrary, according to the study, states like Wisconsin and Michigan indicate significant losses of historical forest biodiversity because historical hotspots are presently cities and towns. Areas that are highly populated change the scope of urban conservation in historic species-rich areas.
"The knowledge of areas that are highly populated, and also historically biodiverse is really helpful to prioritize where to put urban forestry practices into action," Belitz said.
However, the forest biodiversity of rural lands is more complex.
Pearsall said. "Rural lands in the Midwest have been converted to agriculture, so it's less likely that biodiversity is going to be conserved there. However, if the lands are forests or private rural lands, they can maintain biodiversity."
According to Belitz, biodiversity is not affected only by species richness, but also by climate, geology, topography and soils.
"There's differences in hotspots across various areas based on small scale differences, such as climate zones, soil types and land use types, creating soil and climate mixing," Belitz said. "These areas have greater niches that can be exploited by trees, which can be hosted more in those areas, creating the difference of basically heterogeneity of climate niche and soil niche."
Copenheaver said the biggest challenge to land restoration and conservation in the Midwest is the amount of land dedicated to agriculture. As a solution, compromises and selective tree harvesting have proven effective in conservation efforts.
"We find ways to work with private landowners to have biodiversity as one of their management goals," she said. "In forestry, when we harvest timber, we leave trees along the sides of streams and rivers, which improves water quality and keeps some trees and biodiversity on the landscape."
And Pearsall said, "It's important to understand historical biodiversity so we can understand what we have lost through land use change."
"This can be a reminder of biodiversity to people today and reassures us that people can make a difference in their own backyards to help restore biodiversity."
The study was published in the journal Human Ecology.
Akia Thrower writes for Great Lakes Echo.