Climate change promotes hybridisation between deeply divergent species

Area of Science:

• Evolutionary Biology
• Climate Change Ecology
• Herpetology

Background:

• Rare hybridizations between deeply divergent species are frequently observed but poorly understood, often dismissed as anecdotal.
• Existing research primarily focuses on closely related species, overlooking potential drivers for hybridization in more distant taxa.

Purpose of the Study:

• To investigate the underlying causes of rare hybridizations between deeply divergent toad species.
• To determine the role of climate change in facilitating these interspecific hybridization events.
• To project future trends in hybridization likelihood based on climate change scenarios.

Main Methods:

• Combined field observations with long-term data on natural hybridizations, climate, and land-use.
• Utilized field-validated species distribution models for two sympatric European toad species (Bufo bufo and Bufotes viridis).
• Analyzed the impact of climate warming and extreme temperatures on species' life-history traits.

Main Results:

• Climate warming and extreme seasonal temperatures were identified as key factors promoting maladaptive hybridizations.
• Differential effects of climate on the life-history traits of Bufo bufo and Bufotes viridis create opportunities for hybridization.
• Evidence suggests climate change influences hybridization beyond closely related species.

Conclusions:

• Climate change provides an ultimate cause for rare, maladaptive hybridizations between deeply divergent species.
• The frequency of these hybridization events is projected to increase in the near future due to ongoing climate change.
• Findings highlight the broad impact of climate change on species interactions and biodiversity.