Considering differences among individuals is key to conserving biodiversity
According to the study, the persistence of diverse plant and pollinator communities requires the coexistence of specialist and generalist individuals.
A male of Eucera hispaliensis on Lavanda pedunculata. Credit: Curro Molina
For decades, ecology has traditionally relied on species as the basic unit of study to simplify management and data analysis. However, while this approach has provided very valuable insights, it tends to obscure the real diversity of interactions among organisms and their consequences. A new study led by the Doñana Biological Station and published in Ecological Monographs shifts the focus from species to individuals. The study shows that subtle differences in how each individual interacts can play a decisive role in the persistence of ecological communities under environmental change. The research also involved the University of Canterbury (New Zealand) and the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin.
Putting the individual at the centre
Mutualism—interactions in which individuals of different species, such as plants and pollinators, benefit from one another—is a cornerstone of biodiversity. “Ecological research has long assumed that individuals within a species are functionally identical and interact in the same way,” says Blanca Arroyo-Correa, a researcher at the Doñana Biological Station. “Our results challenge this assumption and show that individual-level variation in mutualistic species is critical for their ability to persist under environmental change.”
A new lens on biodiversity
To explore the role of individual variation, the researchers developed a mathematical framework based on the concept of structural stability, which describes an ecosystem’s capacity to maintain its structure and functioning despite environmental disturbances.
The model was applied to data collected in Mediterranean scrublands in Doñana National Park. Over a single flowering season, the team recorded thousands of pollinator visits to hundreds of plants belonging to multiple species. “What we found is that plant species are made up of individuals that differ greatly in how specialised they are,” explains Arroyo-Correa. “For example, some plants interact with only a small number of pollinator species because they are isolated or produce few flowers, while others are far more generalist and attract a wide range of insects.”
The results show that the highest levels of stability occur when populations contain a mix of specialist and generalist individuals. “Ignoring individual variation can lead to misleading conclusions about the stability of ecological communities,” says Pedro Jordano, co-author of the study. “By accounting for this natural variability, we can improve our ability to predict how communities will respond to environmental change.”
Implications for conservation and restoration
As climate change, habitat loss and other pressures threaten diversity within species, populations risk losing the individual variation that helps buffer them against extinction. The study highlights the importance of incorporating individual diversity into conservation and restoration efforts, for example by avoiding overly uniform plantings in restoration projects.
“Conservation strategies tend to focus on species as a whole,” says Ignasi Bartomeus, another co-author of the study and researcher at the Doñana Biological Station. “Our work highlights the need to preserve individual variation, as this allows species to persist when they are part of diverse ecological communities.”
By combining ecological theory with extensive field data, the study provides new tools to anticipate how ecological communities may respond to environmental change and offers valuable guidance for ecosystem management and biodiversity conservation in a rapidly changing world.
Reference
Arroyo‐Correa, B., Bartomeus, I., Jordano, P., Cagua, E. F., & Stouffer, D. B. (2025). Bridging the gap between individual specialization and species persistence in mutualistic communities. Ecological Monographs, 95(3), e70031.
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