Climate change threatens freshwater fish biodiversity and its role in ecosystem functioning

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fish
Fig. 1. Fish
2023-08-10

Climate change could become the biggest threat to biodiversity within this century. Predictions into the future can make decision-makers aware of the potential impacts on biodiversity and support developing strategies proactively to lessen them. This is especially important for freshwater ecosystems that are facing the most severe biodiversity losses.

Researchers from Leiden University assessed the potential impacts of climate change on fish functional diversity in freshwater ecosystems across the world. Functional diversity reflects ecosystem functioning better than simpler metrics like species counts. Depending on the warming level, 6%–25% of the locations globally face a complete loss of functional diversity when assuming no dispersal of fish species. The estimates reduce to 6%–17% when assuming maximal dispersal. The global hotspots of functional diversity loss are in the Amazon and Paraná River basins, areas known for their rich biodiversity (Fig. 2). Impacts on freshwater fish accelerate with increasing climate change, so early mitigation is critical!

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Fig. 2. Functional diversity change categories at warming levels
Fig. 2. Functional diversity change categories at warming levels of 1.5°C (a), 2.0°C (b), 3.2°C (c) and 4.5°C (d), assuming no dispersal of the fish species. The categories consider three facets of functional diversity – richness (FRic), evenness, and divergence – which sometimes follow contrasting spatial patterns (no FRic loss, gain by two, gain by one).

While mitigating climate change requires concerted efforts from various stakeholders across the world, lifestyle changes by individual citizens are also important and can contribute to protecting biodiversity. Protecting biodiversity also maintains the provision of ecosystem services, which, in turn, benefits human societies.

Similar research on the climate change impacts on functional diversity will also be conducted for terrestrial and marine ecosystems within the Horizon Europe project BAMBOO.

Laura Scherer, Leiden University

Source: Scherer, L., Boom, H. A., Barbarossa, V., & van Bodegom, P. M. (2023). Climate change threats to the global functional diversity of freshwater fish. Global Change Biology.

Source of picture: Photo by Milada Vigerova on Unsplash

Figure from Scherer, L., Boom, H. A., Barbarossa, V., & van Bodegom, P. M. (2023). Climate change threats to the global functional diversity of freshwater fish. Global Change Biology.