idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
A new study led by researchers from the Museum für Naturkunde Berlin reveals how the loss of large mammals can ripple through ecosystems in unexpected ways, even affecting amphibian larvae living in temporary ponds. By examining changes in nutrient dynamics over more than two decades, the researchers show that declines in large herbivores are associated with a system-wide reduction in nitrogen isotope values in aquatic habitats, highlighting how disruptions in terrestrial wildlife populations can cascade across ecosystem boundaries.
The study, published in Ecology and Evolution, investigated how declines in large mammalian herbivores in Comoé National Park (Ivory Coast) may alter nutrient dynamics in aquatic ecosystems. By analyzing stable isotopes in tadpoles collected before and after major wildlife declines, the researchers uncovered clear evidence of ecosystem-wide change.
“We initially set out to test whether changes in habitat structure and community composition, which we had shown in a related study, would lead to shifts in tadpole diets,” explains Dr Mark-Oliver Rödel, Museum für Naturkunde Berlin.
To explore this, the team analyzed stable isotopes of nitrogen and carbon in tadpoles, which is a powerful method to understand food webs and nutrient flows. When Ulrich Struck, head of the stable isotope lab at the Museum für Naturkunde Berlin, first examined the data, one pattern stood out immediately: a consistent directional drop in nitrogen values.
Nick Ewald, co-lead author of the study, explains: “What we saw was not just species-specific responses. Instead, we were looking at a systemic drop in nitrogen isotope values across all tadpoles.” Indeed, the study shows a clear decrease in δ¹⁵N values across multiple tadpole taxa following the decline of large herbivores. This suggests a shift at the base of the food web rather than changes in feeding behavior alone.
Guillaume Demare, co-lead author, highlights the potential implications: “Such a systemic change can be significant. Lower nitrogen isotope values could reflect nitrogen limitation in these ecosystems. While we need more data to confirm this, it raises concerns about how resource quality might affect tadpole development.”
This could have important consequences. In temporary savanna ponds, tadpoles must grow quickly and metamorphose before the water dries out. If nutrient quality declines, growth rates may slow, reducing the chances of surviving to adulthood.
Beyond amphibians, the study highlights a broader ecological message: large mammals play a crucial role in linking ecosystems. By moving nutrients across landscapes, for example through grazing and defecation, they connect terrestrial and aquatic habitats. “Our work shows that large mammals are not just important for terrestrial ecosystems,” the authors conclude. “They also help sustain aquatic systems. When they disappear, the effects can cascade across ecosystem boundaries.”
The ‚Open Access‘ publication ‘Ewald, N., G. Demare, J. Glos, U. Struck & M.-O. Rödel (2026): Shift of nitrogen and carbon stable isotopes in temporary pond tadpoles following the decline of large mammalian herbivores. – Ecology and Evolution, 16: e73508’ can be downloaded under https://onlinelibrary.wiley.com/doi/10.1002/ece3.73508.
Criteria of this press release:
Journalists
Biology, Chemistry, Environment / ecology, Zoology / agricultural and forest sciences
transregional, national
Research results, Scientific Publications
English
You can combine search terms with and, or and/or not, e.g. Philo not logy.
You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).
Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.
You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).
If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).
