idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
A global analysis of fish biodiversity using environmental DNA (eDNA) reveals how human activity and climate influence biodiversity patterns in river ecosystems. An international research team led by the University of Zurich, Eawag and Yunnan University has found that in warmer climates biodiversity accumulation is more pronounced as river catchment size increases, while human activities weaken this relationship.
Biodiversity is under threat worldwide, as reflected in the declining number of species and the changing composition of ecological communities. Understanding the state of biodiversity and how it is changing is essential for effective environmental management and policymaking. However, biodiversity data are often difficult to obtain, especially in remote yet species-rich regions such as the tropics. Another problem is the pace at which the changes are occurring, with many ecosystems declining at a rate that exceeds the capacity of existing monitoring methods, both in terms of time and space.
Environmental DNA from 113 river systems worldwide
A new study now provides a comprehensive global analysis of fish biodiversity in rivers, revealing how human activity and the local climate influence biodiversity patterns in river ecosystems. Led by scientists from the University of Zurich (UZH) and Yunnan University in China, the study uses a novel, DNA-based approach for assessing biodiversity known as environmental DNA (eDNA) monitoring. As part of a global collaborative effort, the researchers combined eDNA data from 113 river systems across five continents, covering nearly 2,000 sampling sites.
“Protecting biodiversity depends on sufficient data to document the state of biodiversity and how it is changing. Our research shows how technological advances can directly contribute to the understanding of biodiversity across different dimensions,” says Yan Zhang, postdoctoral researcher and first author of the study.
Climate and human activity shape riverine biodiversity patterns
The study identified global patterns in riverine fish biodiversity, revealing that catchments in warmer climates consistently accumulated greater biodiversity as catchment size increased. This highlights the crucial role of climate in shaping biodiversity patterns. However, the researchers found that this positive relationship weakens in areas with higher levels of human activity. The findings suggest that human activity can alter large-scale biodiversity patterns by constraining fish biodiversity across river catchments. “We found that the effects of human activity varied across regions, highlighting the need for locally adapted protection measures,” says principal investigator Florian Altermatt, Professor of Aquatic Ecology at UZH and Eawag.
The researchers found that not only species richness, but also other measures of biodiversity, including functional diversity and genetic sequence diversity, showed stronger negative responses to human activity in larger river catchments. For example, phylogenetic diversity, which reflects the evolutionary relationships among species, was particularly affected by human activity, especially in smaller river catchments. “Our findings suggest that biodiversity responses to environmental gradients and human influence are complex and vary depending on the specific biodiversity aspect being measured,” Yan Zhang adds.
eDNA enables rapid, large-scale biodiversity monitoring
The study demonstrates the potential of eDNA as an effective tool for rapid, large-scale biodiversity monitoring. Unlike traditional methods involving gillnets or electrofishing, eDNA monitoring does not require fish to be actively captured. Instead, researchers extract DNA directly from water samples and sequence it to identify species-specific genetic signatures, enabling them to infer which species are present in an ecosystem. “The field of biodiversity research is becoming a data science, where unprecedented integration of data allows new insights, also for global biodiversity policymaking,” says Florian Altermatt.
By enabling researchers to detect and attribute biodiversity change, eDNA can support the development of more effective ecosystem conservation strategies and help countries meet global biodiversity targets, including those set out in the Global Biodiversity Framework (GBF). “Our research not only advances scientific understanding but also provides policymakers with essential tools for protecting freshwater ecosystems,” Altermatt concludes.
Prof. Dr. Florian Altermatt
Department of Evolutionary Biology and Environmental Studies, University of Zurich, and
Department of Aquatic Ecology, Eawag, Switzerland
+41 58 765 55 92
florian.altermatt@uzh.ch
Prof. Dr. Xiaowei Zhang
State Key Laboratory of Vegetation Structure, Function and Construction
School of Ecology and Environmental Science
Yunnan University, China
+86 151 51 88 12 87
zhangxw@ynu.edu.cn
Yan Zhang, Heng Zhang, ..., Xiaowei Zhang, Florian Altermatt. A unified analysis of global riverine eDNA reveals common associations of fish biodiversity with drainage characteristics. Nature Ecology & Evolution. May 2026. DOI: https://doi.org/10.1038/s41559-026-03106-1
https://www.news.uzh.ch/de/articles/media/2026/fisch-biodiversitaet.html
In many riverine systems, fish and fisheries are economically important – Fishermen at Shaying river ...
Source: Florian Altermatt
Copyright: UZH/Eawag
A water sample from 30 m depths in the water column from the Yangtze River is taken for subsequent e ...
Source: Florian Altermatt
Copyright: UZH/Eawag
Criteria of this press release:
Journalists
Biology, Environment / ecology, Oceanology / climate
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).
