• Species numbers alone do not fully capture how ecosystems are changing. • In a global study, scientists analyzed long-term data from nearly 15,000 marine and freshwater fish communities. • They found that fish food webs have changed substantially over recent decades, even in places where the number of species (species richness) has remained stable. • Published in Science Advances, the study shows consistent shifts in species composition, body size, and feeding relationships, highlighting that changes in species traits such as body size and interactions can alter ecosystem structure without obvious changes in species richness.
Article Summaries:
- A global analysis of nearly 15,000 marine and freshwater fish communities shows that food webs are shifting even when species counts stay constant. Researchers used long‑term data to track changes in species composition, body size, and feeding interactions over recent decades. The study, published in Science Advances, found that fish tend to be smaller and trophic relationships are rearranging, indicating that alterations in species traits can restructure ecosystems without affecting overall species richness. These findings suggest that monitoring only species numbers may miss significant ecological changes.
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