Climate change fluctuations can increase population abundance and range size

Area of Science:

• Ecology
• Climate Change Biology
• Population Dynamics

Background:

• Species are shifting their thermal niches poleward and upward due to climate change.
• The impact of climate change on species is linked to the speed of niche movement, but the effects of niche movement fluctuations are less understood.
• Environmental fluctuations can have both negative and positive effects on populations.

Purpose of the Study:

• To investigate how fluctuations in niche movement speed affect species' persistence, abundance, and realized niche width under climate change.
• To determine the conditions under which niche movement fluctuations lead to positive or negative population outcomes.

Main Methods:

• Modeling population dynamics under climate change scenarios.
• Analyzing the impact of fluctuations around an average niche movement speed.
• Comparing outcomes for species with different life history traits (e.g., lifespan).

Main Results:

• The effect of niche movement fluctuations depends on their manifestation and the relative timescales of population growth and climate change.
• When populations are near extinction at the average niche movement speed, fluctuations accelerate their decline.
• Populations not close to extinction can experience increased abundance and/or realized niche width due to these fluctuations.

Conclusions:

• Niche movement fluctuations under climate change present a complex challenge for species persistence.
• The outcome of these fluctuations is context-dependent, influenced by population status and life history traits.
• Understanding these dynamics is crucial for predicting species' responses to ongoing climate change.