Nav: Home

Virginia Tech researchers explore causes of land cover change in African savannas

November 08, 2017

A new study by Virginia Tech researchers tracks land cover changes in the Chobe district of Northern Botswana and provides information that will allow governments and nonprofit organizations to improve dryland management strategies in the region.

The study was published in Arid Land Systems: Science and Societies, a special issue of the journal Land.

"There is an incredibly dynamic and complex relationship between land cover types that are constantly changing. Not much is known about what happens in these transitional savanna ecosystems located between more arid and wetter climate zones, information critical to their management," said lead author J. Tyler Fox, who earned his doctorate in fish and wildlife conservation in Virginia Tech's College of Natural Resources and Environment in 2016.

"If we can understand how the landscape has changed over decades and what that does to water quality, human health, and ecosystem health, we can begin to make predictions for the future," said senior author Kathleen Alexander, professor of wildlife conservation in the College of Natural Resources and Environment and a Fralin Life Science Institute affiliate.

The team conducted the study in Alexander's long-term field site through CARACAL (Centre for Conservation of African Resources: Animals, Communities, and Land Use), a nonprofit organization she and her husband, Mark Vandewalle, established in Northern Botswana. Vandewalle, a co-author of the study, is a wildlife biologist with a focus on ecosystem function in African savanna habitats and serves as CEO of CARACAL.

The study, funded by the National Science Foundation and Forest Conservation Botswana, examined Landsat satellite data from the past 30 years to track broad land cover change in the Chobe district, a 21,000-square-kilometer area encompassing urban, rural, communally managed, and protected land. The Botswana government wanted to better understand how land cover is changing over time and how this might impact ecosystem services.

"The region's savanna landscapes provide critical resources for both people and animals. Communities in these areas rely heavily on forest resources, such as firewood, thatch for roofs, and plants for food and medicine. These areas are also used in tourism and even in spiritual or cultural ceremonies," noted Fox, who is currently a post doctoral fellow at the University of Arkansas.

"This study is one of the first to quantitatively examine the loss of forested areas and other land cover changes in savanna environments," said Richard Yuretich, program director for the National Science Foundation's Dynamics of Coupled Natural and Human Systems Program, which funded the research. "The complex relationships among climate, ecology, and human activities reveal the overwhelming influence of people on the loss of woodlands. This paves the way for effective management of these diminishing resources."

The study observed a long-term trend of decreasing woodland cover and increasing shrubland. Grasslands also varied considerably over the study period. Surprisingly, loss of woodlands tended to be higher in protected forest reserves compared with the larger Chobe District.

"We looked specifically at drought, fire, and elephant disturbance as possible causes for these changes," Fox said.

"Dryland ecosystems are especially vulnerable to human impacts," Alexander added. "Domestic animals, wildlife, and people congregate in riparian areas near scarce water resources, impacting these regions. Using this approach, we can begin to track change and identify possible drivers, system couplings, and hot spots of degradation. We can see how various stressors are affecting the landscape and begin to engage proactive rather than reactive management approaches."

According to Vandewalle, many people in Botswana believe that there has been a linear loss of trees, a progression from forested land to shrubs to bare ground.

"Our data, however, reveal extensive regeneration of trees in certain areas in association with the right conditions," Vandewalle noted. "Change is complex, dynamic, and can be bidirectional in these systems."

The team also discovered that while many people believe the region's fast-growing elephant population is a major driver of forest cover loss, there was little evidence for this in their analysis.

Fire, however, was a driving force in land cover change. Fox explained that over a 13-year period, there were nearly 10,000 fires in the Chobe district. More than 85 percent of those happened during a time when there were no storms or lightning, meaning that most of the fires originated from human activities.

"We were able to pinpoint where and when fires were happening, which allowed us to make some fire management suggestions," Fox said. "For instance, thatch collection activities appear related to fire hotspots, which extended into several of the protected forest reserves. These areas can be more intensively targeted for management and outreach activities. People rely heavily on natural resources extracted from this landscape and need to have sustainable access to those materials to ensure livelihood security."

Alexander is working with the Botswana government to develop an active monitoring approach based on the groundwork laid by this study.

"Across the globe, forest products remain an essential natural resource," she said. "We need to understand the status of those resources and identify the primary threats and drivers. Decadal studies of this nature are necessary to understand system dynamics and fundamental to the development of improved and targeted management."

Alexander also noted that the implications of the study have the potential to benefit not only Botswana, but dryland systems globally.

"Drylands represent over 41 percent of the global landmass and are extremely vulnerable to human impacts," she added. "What we're learning in Botswana has application to other drylands that are under increasing threat and pressure to supply human and animal needs."
-end-


Virginia Tech

Related Conservation Articles:

Environmental groups moving beyond conservation
Although non-governmental organizations (NGOs) have become powerful voices in world environmental politics, little is known of the global picture of this sector.
Hunting for the next generation of conservation stewards
Wildlife ecology students become the professionals responsible for managing the biodiversity of natural systems for species conservation.
Conservation research on lynx
Scientists at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and the Leibniz Institute for Molecular Pharmacology (Leibniz-FMP) discovered that selected anti-oxidative enzymes, especially the enzyme superoxide dismutase (SOD2), may play an important role to maintain the unusual longevity of the corpus luteum in lynxes.
New 'umbrella' species would massively improve conservation
The protection of Australia's threatened species could be improved by a factor of seven, if more efficient 'umbrella' species were prioritised for protection, according to University of Queensland research.
Trashed farmland could be a conservation treasure
Low-productivity agricultural land could be transformed into millions of hectares of conservation reserve across the world, according to University of Queensland-led research.
Bats in attics might be necessary for conservation
Researchers investigate and describe the conservation importance of buildings relative to natural, alternative roosts for little brown bats in Yellowstone National Park.
Applying biodiversity conservation research in practice
One million species are threatened with extinction, many of them already in the coming decades.
Making conservation 'contagious'
New research reveals conservation initiatives often spread like disease, a fact which can help scientists and policymakers design programs more likely to be taken up.
Helping conservation initiatives turn contagious
New research shows that conservation initiatives go viral, which helps scientists and policymakers better design successful programs more likely to be adopted.
Overturning the truth on conservation tillage
Conservation tillage does not lower yield in modern cropping systems.
More Conservation News and Conservation Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.