As humans break up forests and fragment habitats, it’s not just species that are lost but also the way ecosystems work, a new study finds.
A paper recently published in Ecology Letters compares how mammals are connected through food webs – meaning who eats who or what – in 127 protected areas across Africa. It’s the first study to compare food web similarity at a continental scale.
Working with MSU Assistant Professor Lydia Beaudrot , Rice University Ph.D. student Annie Finneran learned that fragmented habitats are a significant predictor of how similar food webs are in the Congo Basin’s tropical forests. The study adds to the growing body of research pointing to the negative impact of humans on tropical forest wildlife in protected areas.
“Protected areas are critical strongholds for conservation,” Beaudrot said. “At the same time, the wildlife they’re trying to protect are not immune to the effects of human encroachment.”
The study used satellite images of sites across sub-Saharan Africa to identify habitat fragmentation, or disruption caused by human activity, and vegetation amount in each site. These images, combined with mammalian species known to be at each site and mammalian predator-prey interactions, were used with a network analysis technique developed by César Uribe, the Louis Owen Assistant Professor of Electrical and Computer Engineering at Rice.
The network analysis showed that a major defining factor in the food webs was primary productivity, or how much vegetation an ecosystem had. Since the researchers were able to look across a wide variety of ecosystems — from savannahs to deserts to rainforests — they could see that the similarity in quantity of vegetation predicted food web structure.
“The amount of energy available ultimately controls the amount of vegetation in a system,” Beaudrot said. “We found that similarity in the amount of vegetation strongly correlated with the similarity of food webs, regardless of the location or type of ecosystem.”
While the shaping forces of primary production were found across sub-Saharan Africa, their second finding was specific to the Congo Basin, a tropical forest region spanning approximately 3.7 million square kilometers. The Congo Basin, an area slightly larger than India, is one of the largest intact tropical forest regions in the world.
There, researchers found evidence that fragmentation, or disruption of habitat from agriculture or human development, shaped the food webs across the 10 Congo forest sites in the study.
“In the Congo Basin,” Finneran said, “we found that tropical forests with similar levels of fragmentation had more similar food webs. This may indicate that fragmentation predictably disrupts species with similar ecological roles.”
Though the sites Finneran examined were protected, the extent of the protection varies depending on the country and status of each individual site. Food webs in these systems can undergo further structural changes, or changes to predator-prey interactions, if fragmentation continues to happen.
This project was funded by the National Science Foundation’s Division of Environmental Biology (2213568) and Division of Computing and Communication Foundations (2443064).
Ecology Letters
Food Web Similarity Increases With Productivity Similarityat a Continental Scale
20-Mar-2026