MSU researchers use open-access data to study climate change effects in 24,000 US lakes
MSU researchers use open-access data to study climate change effects in 24,000 US lakes
EAST LANSING, Mich. – Each summer, more and more lake beaches are forced to close due to toxic algae blooms. While climate change is often blamed, new research suggests a more complex story: climate interacts with human activities like agriculture and urban runoff, which funnel excess nutrients into the water. The study sheds light on why some lakes are more vulnerable than others and how climate and human impacts interact — offering clues to why the problem is getting worse.
Michigan State University researchers discovered key climate-related patterns in algal biomass levels and change through time for freshwater lakes. They used novel methods to create and analyze long-term datasets from open-access government resources and from satellite remote sensing. This research, published in Proceedings of the National Academy of Sciences, provides crucial insights into how climate affects lake ecosystems.
The team studied chlorophyll levels, a measure of algal biomass, in lakes across the U.S. from the last 34 years. Climate change is thought to intensify lake algal blooms and increase the likelihood of “regime shifts,” or sudden and long-lasting changes in the structure and function of an ecosystem.
“Our research demonstrates that the relationship between climate change and algal biomass is more complex than previously understood,” said Patricia Soranno, a professor in the MSU College of Natural Science and one of the co-lead authors of this study. “While climate change is a significant driver, we found that the impacts are not always gradual or predictable. To effectively manage and protect lakes, we need to study these effects in many different local and regional contexts.”
Traditionally, researchers have struggled to predict changes in algal biomass using available lake sampling data. To overcome this challenge, the MSU team, led by Soranno and Patrick Hanly, a quantitative ecologist in the MSU College of Agriculture and Natural Resources, developed a novel approach. Leveraging over 30 years of publicly available satellite imagery, researchers used machine learning to create an unprecedented dataset of algal biomass in 24,452 U.S. lakes. The team combined this dataset with LAGOS-US, a large geospatial research platform that describes lake features of the U.S. that Soranno and Kendra Spence Cheruvelil, dean of MSU’s Lyman Briggs College and others have spent years developing. Their analysis is one of the first to document a causal link between climate and algae.
They found that climate caused changes in algal biomass in about a third of tested lakes (34%), but in unexpected ways. For lakes with climate-related changes, only 13% were prone to regime shifts, only 4% increased in productivity, whereas 71% of them had abrupt, but only temporary changes.
This lack of a general and sustained change may appear reassuring. However, annual abrupt changes in biomass that were detected have not typically been measured, leaving these abrupt changes understudied. This has led to gaps in understanding of the effects of climate on water quality such as algal biomass. Luckily, the methods used in this paper can capture these abrupt fluctuations that traditional approaches might miss.
This large-scale approach also uncovered variability in climate-driven algal responses that depend on environmental conditions and the level of human disturbance. Lakes with low to moderate human impacts were more likely to respond to climate, while lakes already under heavy human pressures, like increased nutrient input from agriculture, were less likely linked to climate.
“Our findings emphasize the importance of considering both climate and other measures of human impacts when assessing the health of lakes, especially over decades,” said Lyman Briggs College. “This research provides a crucial foundation for developing effective strategies to mitigate the impacts of these stressors and protect the valuable resources that lakes provide.”
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Michigan State University has been advancing the common good with uncommon will for 170 years. One of the world’s leading public research universities, MSU pushes the boundaries of discovery to make a better, safer, healthier world for all while providing life-changing opportunities to a diverse and inclusive academic community through more than 400 programs of study in 17 degree-granting colleges.
For MSU news on the web, go to MSUToday or x.com/MSUnews.
Journal
Proceedings of the National Academy of Sciences
Article Title
Abrupt changes in algal biomass of thousands of US lakes are related to climate and are more likely in low-disturbance watersheds
Article Publication Date
24-Feb-2025
MSU researchers bring new approach to stopping the biodiversity crisis
Feb. 25, 2025
EAST LANSING, Mich. – What if saving one animal species from extinction at a time isn’t the most effective approach? Michael Belitz, a Michigan State University postdoctoral researcher in the Zipkin Quantitative Ecology Lab, asked himself that question during his graduate work protecting a single butterfly species.
As he studied species-level conservation, he found himself thinking about how multiple species interact and how they responded to warming temperatures, extreme weather and urbanization. He wondered if he might find more success protecting multiple species in a habitat instead of focusing on just one.
Now, Belitz has coined a term for this work: assemblage-level conservation. In a newly published perspective article in Nature Reviews Biodiversity, Belitz and his colleagues advocate for the conscious protection of multiple species at the same time. They argue that conservation targeting groups of related species is an effective way to quantify, predict and manage multiple species. The time is right for a perspective shift, they argue, not only by researchers, but also by land managers, policymakers and conservationists.
“We are excited to have this perspective piece published in one of the first issues of the journal Nature Reviews Biodiversity,” Belitz said. “My hope is that by defining and coining ‘assemblage-level conservation,’ funds and efforts can be more targeted and streamlined.”
Interdisciplinary collaboration between biology, modeling and natural resource management has opened the door to studying the many complex challenges related to biodiversity loss. Computational power, advances in statistical modeling and increased data availability make assemblage-level conservation possible.
At the forefront of assemblage-level data analysis, the Zipkin lab uses statistical analyses to simultaneously model many species from animal communities, providing a holistic understanding of biodiversity and the causes of biodiversity declines. With this approach, Belitz and his colleagues can include more species at larger scales, leading to better estimates for less studied and rare species. The lab also works with land managers and conservation professionals to produce conservation-relevant outcomes from their models.
“Assemblage-level analyses provide us with an opportunity to evaluate how, where and why individual species and whole communities are declining,” said Elise Zipkin, Red Cedar Distinguished Professor at MSU and senior author on the paper. “It also provides us with new opportunities to implement strategic conservation actions in a time of accelerated biodiversity loss.”
In the perspective article, the authors explain some of the advantages of assemblage-level conservation over two other common conservation methods: species-level conservation and ecosystem-level conservation.
A species-by-species approach is the most common, but it can be biased toward the conservation of charismatic and large species. This approach also can’t address the full problem in areas where many species are in decline.
Take the example of a flagship species of insect decline — the monarch butterfly. At the species-level, the intervention of planting milkweed has helped monarch populations. However, an assemblage-level approach such as planting a diverse mix of both host and nectar plants for native pollinators has been linked to increased overall pollinator diversity and abundance, while also resulting in more monarchs.
On the other end of the spectrum is ecosystem-level conservation, which aims to protect the physical environment and the services provided within a targeted geographic area. Ecosystem-level conservation is complex and can be hard to manage, especially at regional scales and over long periods of time. Rare and endangered species may be overlooked, and it does not always prioritize biodiversity declines.
That’s where assemblage-level conservation comes in. Management actions that seek to preserve both the number of species in an area and their abundance can benefit both individual species and ecosystem services. One of the Zipkin lab’s ongoing projects is studying the assemblage of butterflies across Midwestern states. Their goal is to figure out how both individual species and the butterfly community as a whole are changing in an effort to prioritize conservation efforts. This collaboration with the U.S. Fish and Wildlife Service and the U.S. Geological Survey will determine what, if any, changes would protect the greatest number of species.
“When thinking about the total number of species that are declining, it sometimes feels that the conservation challenges are insurmountable. Focusing on manageable segments can help keep us moving forward,” Zipkin said. “Our hope is that a shift in perspective to focus on assemblage-level conservation will open up new opportunities to protect biodiversity and mitigate the declines of whole taxonomic groups, such as butterflies.”
The Zipkin lab’s work provides valuable information for protecting biodiversity and has gained recognition. By publicizing the benefits of this method, Belitz hopes their paper will generate more funding and action for assemblage-level conservation — providing broadscale support for the analysts in the lab to the managers on the ground.
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Michigan State University has been advancing the common good with uncommon will for 170 years. One of the world’s leading public research universities, MSU pushes the boundaries of discovery to make a better, safer, healthier world for all while providing life-changing opportunities to a diverse and inclusive academic community through more than 400 programs of study in 17 degree-granting colleges.
For MSU news on the web, go to MSUToday or x.com/MSUnews.
Journal
Nature Reviews Biodiversity
Article Title
A case for assemblage-level conservation to address the biodiversity crisis
