Work

Documenting climate-driven changes in Swiss macroinvertebrate communities with a ‘temperature index’: An evaluation of different sources of thermal preference data

Year: 2025

Type: article

Abstract: Freshwater ecosystems support a disproportionate share of global biodiversity. Freshwater macroinvertebrates are frequently used as bioindicators to assess the ecological status of streams and rivers. However, ongoing climate change is altering the compositions of these communities, highlighting the need for tools to detect climate-related shifts. We propose and evaluate an ecological index based on the SPEcies At Risk (SPEAR) approach to quantify the proportion of species that are sensitive to higher temperatures within Ephemeroptera, Plecoptera and Trichoptera communities. We calculated this index using six different data sources for thermal preferences: experimentally measured thermal tolerances, the mean temperature from global occurrence records (GBIF), preferred temperatures obtained from multivariate species distribution models (SDM), the central temperature tendency derived from Swiss monitoring data according to the KLIWA approach, and two different sources of expert knowledge from a curated trait database. For all sources, we designated the species comprising the lower 50th percentile of thermal preference values as sensitive and the upper half as insensitive to warmer temperatures. To evaluate the performance of the six versions of this SPEAR temperature on a geographic scale, we leveraged data from two Swiss wide monitoring programs including samples from 570 sites for the period 2010–2022 and from 183 sites for 2018–2023. While all six versions recapitulated a declining proportion of sensitive species with increasing water temperature, the relation was strongest when using the KLIWA-based thermal preference classification. On average across all sites, we observed a significant decline of the SPEAR temperature index over the 2010–2022 period, independent of the source for the classification. This is consistent with a signal of warming-related community turnover, or ‘thermophilisation’. These results indicate that the index is suitable to document temperature-associated variation in EPT communities over both time and space. The attempt to derive a similar SPEAR temperature index for fish was not successful.

Source: Ecological Indicators

DOI: 10.1016/j.ecolind.2025.114129

Authors: Imran Khaliq, Anita Narwani, Christoph Vorburger, Nele Schuwirth

Institutions: Swiss Federal Institute of Aquatic Science and Technology, University of Göttingen, ETH Zurich

Language: English

Topic: Freshwater macroinvertebrate diversity and ecology

Subfield: Ecology

Field: Environmental Science

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,650