Double Trouble for Native Species Under Climate Change: Habitat Loss and Increased Environmental Overlap With Non-Native Species

Abstract

Climate change and biological invasions are affecting natural ecosystems globally. The effects of these stressors on native species' biogeography have been studied separately, but their combined effects remain overlooked. Here, we develop a framework to assess how climate change influences both the range and niche overlap of native and non-native species using ecological niche models. We hypothesize that species with similar niches will experience both range reductions and increased niche overlap under future climates. We evaluate this using the ongoing invasion of smallmouth bass (Micropterus dolomieu) and northern pike (Esox lucius) on the native habitats of redband trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) in western North America. Future climate conditions will reduce habitat suitability for native and non-native species, but an increased niche overlap might exacerbate negative effects on native fishes. Our framework offers a tool to predict potential species distribution and interactions under climate change, informing adaptive management globally.

Keywords: biological invasions; ecological niche; northern pike; rivers; salmonids; smallmouth bass; stream networks; trout.