Current distributions and future climate‐driven changes in diatoms, insects and fish in U.S. streams

Aim

Biodiversity on Earth is threatened by climate change. Despite the vulnerability of freshwater habitats to human impacts, most climate change projections have focused on terrestrial systems. Here, we examined how the current distributions and biodiversity of stream taxa might change under mitigated, stabilizing and increasing greenhouse gas emissions.

Location

Conterminous USA.

Time period

Present day to 2070.

Major taxa studied

Stream diatoms, insects and fish.

Methods

We developed species distribution models for 336 freshwater taxa from 1,227 distinct stream localities using water chemistry, watershed and climatic variables. Models based only on climate were used to project changes in the distributions and biodiversity of cold‐ versus warm‐water taxa under representative concentration pathways (RCPs) ranging from 2.6 to 8.5 W/m2.

Results

In all three organismal groups, climate emerged as the strongest predictor of species dist...