Higher predicted climate-change vulnerability for spring-dwelling freshwater biota

Area of Science:

• Ecology
• Environmental Science
• Biodiversity Research

Background:

• Freshwater biodiversity faces threats from climate change, including altered temperature and precipitation.
• Assessing species' vulnerability is challenging due to insufficient data, potentially leading to misinterpretations.
• The caddisfly subfamily Drusinae offers a well-documented model system due to known phylogenetic relationships, distributions, and ecological traits.

Purpose of the Study:

• To assess individual and trait-specific climate change (CC) vulnerability in 47 Drusinae caddisfly species.
• To identify key ecological traits predicting species' responses to climate change.
• To inform conservation strategies by pinpointing vulnerable species and habitats.

Main Methods:

• Species distribution models (SDMs) were developed for 47 Drusinae species.
• Species were categorized by larval feeding guild, stream zonation preference, and endemism.
• Models incorporated climate, topography, and geology data, projected across multiple climate scenarios and general circulation models.
• Dispersal was limited to 500 km, with projections extending to 2080.

Main Results:

• Predicted range changes varied widely (-100% to 197%), with five species facing extinction.
• Altitudinal shifts ranged from -2% to +15%, and distribution centroids shifted between 28 km and 119 km.
• Stream zonation preference emerged as the most significant predictor of climate change vulnerability, outperforming phylogenetic traits.

Conclusions:

• Stream zonation is a critical, non-phylogenetic trait for assessing climate change vulnerability in Drusinae.
• Conservation efforts should focus on species-level monitoring.
• Springs and low-order streams, often housing endemic species, require increased conservation attention due to heightened vulnerability.