Limited evidence for range shift-driven extinction in mountain biota.

Area of Science:

• Ecology
• Climate Change Biology
• Biodiversity Science

Background:

• Mountain ecosystems face rapid species redistribution as organisms track warming temperatures.
• The
• escalator to extinction
• phenomenon suggests mountaintop extinctions and range shift gaps threaten biodiversity.
• Empirical evidence for these pervasive threats in mountain environments remains scarce.

Purpose of the Study:

• To empirically assess the extent and nature of species redistribution in mountain ecosystems.
• To evaluate the validity of proposed threats like mountaintop extinctions and range shift gaps.
• To understand the drivers of observed changes in elevational range limits.

Main Methods:

• Analysis of 8800 historical and modern elevational range limits for 440 animal and 1629 plant species.
• Comparison of observed range shifts against random expectations, incorporating geometric constraints.
• Assessment of extinction debt and range expansion dynamics.

Main Results:

• Little empirical evidence was found to support the proposed threats of widespread mountaintop extinctions and range shift gaps.
• Observed species redistribution largely fell within random expectations, considering geometric limitations.
• Delayed mountaintop extinctions were noted, alongside range expansions of both narrow-range and lowland species.

Conclusions:

• The anticipated severe threats to mountain biodiversity from climate-driven range shifts appear less pronounced than previously suggested.
• Species redistribution dynamics are complex, involving thermal niche underfilling and biotic homogenization.
• Further research is needed to fully understand the long-term consequences for mountain ecosystems.