That's according to research done by Lisa A. Schulte, assistant professor in Iowa State University's department of Natural Resource Ecology and Management and her team of researchers.
"There's been a shift in the entire ecosystem," said Schulte, whose research has recently been published in the journal Landscape Ecology.
For the study, Schulte, along with Laura Merrick of Iowa State; David Mladenoff of the University of Wisconsin, Madison; and Thomas Crow and David Cleland of the U.S. Forest Service, took forest composition information as described in the Public Land Survey from the mid-1800s and compared it with today's forests.
She found that none of the areas surveyed - from Minnesota to Wisconsin to Michigan - have the same tree species makeup as they did 200 years ago.
"This system was made up of largely conifers with some deciduous trees, and now we have the opposite," she said.
Conifers -- mostly pines and other evergreens -- have gotten more scarce while deciduous trees such as aspen, birch and maple have taken their place. Trees in today's forests also tend to be smaller.
"Our analysis shows a distinct and rapid trajectory of vegetation change toward historically unprecedented and simplified conditions," Schulte's published paper says.
"In addition to overall loss of forestland, current forests are marked by lower species diversity, functional diversity and structural complexity compared with pre-Euro-American forests."
The changes have come from several stresses on the ecosystem including pests, diseases, timber harvest and high populations of white-tailed deer, which feed on young trees, according to Schulte.
The effect of humans may be the most important factor in the shift.
"Human land use of forested regions has intensified worldwide in recent decades, threatening long-term sustainability," the report says.
"Primary effects include conversion of land cover or reversion to an earlier stage of successional development. Both types of change can have cascading effects through ecosystems; however, the long-term effects where forests are allowed to regrow are poorly understood."
What is understood, says Schulte, are the stresses the forest changes are having on wildlife, including birds. Schulte has looked at several species of warblers that have historically inhabited the area. According to her findings, the outlook for them doesn't look good.
"These birds don't have much habitat at present, compared to historical times," she said.
They are also an important and beautiful element of biodiversity, she said. They perform an important function in these forests by eating insects that can become forest pests.
Among natural resource professionals, the forests in the Upper Midwest had been suspected to be changing for some time, according to Schulte, but now there is evidence to support the theories.
"We knew that these kinds of changes had happened," she said. "But this is the first paper to really quantitatively look at it across the entire region. So, anytime you can quantitatively show something, it has a lot more power than simple conjecture."
Lisa Schulte | EurekAlert!
Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta
Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
22.01.2018 | Materials Sciences
22.01.2018 | Earth Sciences
22.01.2018 | Life Sciences