Sunday, May 31, 2026

Rwenzori Mountains’ first major fire in 12,000 years marked new era for climate

Penn State researcher who contributed to findings says effects of blaze continue to threaten rare pristine alpine environment

Penn State

Students return from collecting a core sample in a lake in Uganda's Rwenzori Mountains. — image:

Doctoral student Caleb Norville of Penn State and Meredith Parish of George Mason University return from collecting a core sample in a lake in Uganda's Rwenzori Mountains.
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Credit: Courtesy Penn State

UNIVERSITY PARK, Pa. — For the past several years, Penn State geoscientist Sarah Ivory and her students have been among a team of scientists scaling the East African Rwenzori Mountains, collecting sediment core samples from lakes formed at the end of the last ice age as glaciers began receding in the region some 12,000 years ago.

Among those cores was a surprising revelation: A 2012 wildfire that ravaged 16 square miles of the forest and alpine landscapes at more than 13,000 feet above sea level was unprecedented in at least the last 12,000 years. The researchers also found evidence in fossilized pollen that the fire significantly shifted the region’s ecology. Led by Andrea Mason, a doctoral candidate at Brown University, the team recently published these findings in the journal Nature.

The blaze in the alpine moorland surprised forest experts who assumed the climate was too cold and too wet for fires to start and to spread, Ivory said.

Within the cores, researchers looked at the remnants of charcoal to piece together the fire history of the area since the lakes originated. The cores show no fire activity for about 10,000 years. A slight increase in fire activity about 2,000 years ago — coinciding with an increase in human activity in the region — was recorded in a lower elevation lake. In 2012, the amount of charcoal in the cores shot up more than 100 times, aligning with the timing of the blaze at the border of Uganda and the Democratic Republic of Congo, at higher elevation. Researchers also assessed historic pollen records to determine there were dramatic shifts in the region’s ecology over the past 2,000 years as fire increased.

“The fact that this one fire in 2012 is the only fire that’s happened on this mountain for the entire existence of the lake is mind blowing,” Ivory said. “It’s like the image of a plastic bag in the Mariana Trench. We shouldn’t see human influence in an area that’s this remote, but it’s there.”

The team trekked the mountainside over a period of nearly two weeks, collecting sediment cores from two lakes: Lake Mahoma at about 9,000 feet and Lake Kopello in the alpine zone around 13,000 feet. Lake runoff and wind concentrated indicators into the soft underwater beds captured in the cores that tell us about past plants and climates on the mountain like pollen grains, leaf waxes, fossil bacteria and other biomarkers.

One goal of the project, Ivory said, was to help understand rapid changes to the low-lying village more than 10,000 feet below the Ugandan peaks. The Rwenzori Mountains National Park, a UNESCO World Heritage Site in Uganda, is home to the last remaining glacier that numbered in the dozens roughly 100 years ago. In that time, the region has lost more than 90% of its glacial ice.

In the village of Kilembe, deadly floods, landslides and mudslides have ravaged infrastructure, homes, farmland and livestock in recent years. In her research at large in Africa and parts of the Middle East, Ivory is assessing how warming since the last ice age has and continues to affect ecosystems. She and her students have been assisting with reforestation and forest mapping to combat the effects of climate change in the area.

The fire in the alpine region is another sign of change, Ivory said. Kilembe experienced massive flooding the year following the fire — which burned 18% of the catchment above the village. The unpredictability of the river that runs through the village continues to plague the community, Ivory said, with continued flooding that permanently knocked out power years ago.

“Whenever it rains, everything is disrupted,” Ivory said. “Flooding destroyed bridges and forced boulders into the river, making it difficult to rebuild what was there. It’s really transformed a community just downstream from the 2012 fire.”

Another key finding, Ivory said, was told through the pollen records analyzed at Penn State. The pollen revealed massive changes associated with early human fires as well as more recent fires driven by human-induced climate change to the ecology of the Rwenzori Mountains, one of the most unique and biodiverse mountainous regions on the planet. Much like isolated areas such as the Galapagos Islands offer a glimpse of evolutionary changes, this remote area of Uganda is a hot spot for ecological research and discovery, Ivory said.

The Rwenzori Mountains belong to a network of Afroalpine “sky islands,” isolated, high-altitude environments that support unique plant and animal life found nowhere else on Earth. Comparable systems, such as Mount Kilimanjaro and Mount Kenya, have also seen recent wildfire activity, suggesting that rising temperatures may be altering ecosystems that were once naturally safeguarded by extreme alpine conditions.

Pollen records showed extensive changes in plant life, beginning around 2,000 years ago. This period coincides with an increase in human intervention and agricultural practices. At lower elevation, pollen associated with rainforest trees declined after the period when fires were detected, while pollen associated with bamboo and other grasses increased.

Since 2012, Ivory said, the slow growing mountainside trees have remained damaged and the forest is at risk of ecosystem transformation, especially if fires continue to persist.

“The Rwenzori Mountains have one of the most diverse and pristine expressions of this type of vegetation,” Ivory said. “Similar areas have a lot more disturbance and a lot more fire. Until recently, this was a holdout; it was one of the best examples of this special ecosystem and now that’s under threat.”

In addition to Ivory and Mason, co-authors include Meredith Kelly, Dartmouth College; Bob Nakileza, Makerere University; Eleanor Pereboom and James Russell, Brown University; and Richard Vachula, Auburn University.

Journal

Nature

DOI

10.1038/s41586-026-10511-w

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Twenty-first century emergence of alpine fire in Central African mountains

Meredith Parrish and Edson Kule, of Rwenzori Trekking Services, subsample a sediment core from a glacial lake in Uganda.

This view from Bamwanjara Pass with view of Margarita Peak and its glacier in the distance is part of an isolated, high-altitude environments that support unique plant and animal life found nowhere else on Earth.

Credit

Courtesy of Penn State

Common protective soybean seed treatment may not increase profitability

Penn State

UNIVERSITY PARK, Pa. — Many soybean farmers use seeds treated with fungicides to ward off disease, but the profits from these increased yields might not offset the cost of the treatment in most cases, according to a study published in Scientific Reports by researchers at Penn State.

The researchers analyzed how seed treatments affect yield and profitability in soybean farms in the Midwest and found that yield gains were modest and often did not offset the added cost of the treatment. Additionally, financial benefit was likely only when seed treatment costs were low and soybean prices were high.

Paul Esker, professor of epidemiology and of field crop pathology in the College of Agricultural Sciences and lead author on the study, said the findings suggest that growers may want to carefully evaluate the use of fungicide seed treatments on their farms.

“Farmers often talk about putting money in their pockets, and our research suggests that this can occur by reducing input costs rather than by assuming an economic gain from using treated seeds,” said Esker, who is also affiliated with the Plant Institute in the Huck Institutes of the Life Sciences. “Growers may want to use treated seeds only in specific, high-risk situations or after verifying a positive return-on-investment.”

The use of fungicide-treated seeds has risen sharply in the last few decades, the researchers said. While about 8% of soybean seeds were treated with fungicide in 1996, that figure rose to 60% to 75% by 2015.

Despite their popularity, Esker said their use may not result in higher profits for farmers. Additionally, he noted, unnecessary use of fungicides could result in potentially harmful effects on beneficial microbes in the seeds and soil.

“Adoption of seed treatments has continued to increase in U.S. soybean production systems, but uncertainty remains about whether their use is necessary,” Esker said. “Furthermore, given the parallel questions about the use of seed-treatment insecticides, we recognized that addressing them could go a long way toward helping farmers make better soybean management decisions.”

For the study, the researchers analyzed data from both randomized controlled trials and large-scale, on-farm observational studies previously conducted by other teams.

Data from RCTs was limited to studies in the U.S. Midwest that included crop data from both treated seeds and untreated control seeds. Observational data included self-reported information from growers across three growing seasons from 2014 to 2016 and 10 Midwest states.

“This approach moves us away from a purely correlative interpretation of the results and aligns more closely with the questions that farmers often ask us,” Esker said.

Analysis of data from randomized controlled trials found an average yield increase of 22.2 kilograms per hectare (kg/ha) — or about 19.81 pounds per acre — that could be attributed to fungicide seed treatments. Analysis of observational data found a similarly small average yield gain of approximately 36 kg/ha, or about or about 32.12 lbs/acre.

Additional simulations showed that these gains in crop yields often didn’t offset the costs of seed treatment.

“Our results add to a growing body of evidence that fungicide seed treatments do not provide consistent, reliable protection against downside yield loss risk,” Esker said. “They also will help us collaborate with farmers to determine under what conditions a fungicide seed treatment may be beneficial.”

The findings also raise concerns, the researchers said, about the widespread use of fungicide seed treatments on the microbiomes of seeds and their surrounding soil. Seeds and soils have unique compositions of microbes that benefit germination and seedling development, which could be disrupted by unnecessary fungicide use.

“Given the small economic benefits and these known ecological risks, policymakers may want to prioritize support for research and extension programs that help growers identify the specific conditions where seed treatments are likely to be profitable,” Esker said.

In the future, the researchers said the development of tools to assess specific fields’ pathogen risk may be a more sustainable and economical approach than the current widespread use of preventative fungicides.

Denis A. Shah, Kansas State University; Spyridon Mourtzinis, Tatiane Severo Silva and Shawn P. Conley, University of Wisconsin-Madison; and Patricio Grassini, University of Nebraska-Lincoln, also co-authored the study.

The U.S. Department of Agriculture National Institute of Food and Agriculture, Wisconsin Soybean Marketing Board, North Central Soybean Research Program, and the United Soybean Board helped support this research.