Non-climatic constraints on upper elevational plant range expansion under climate change

Area of Science:

• Ecology
• Climate Change Biology
• Forest Science

Background:

• Predicting climate change-driven species range shifts is hindered by poor understanding of non-climatic limiting factors.
• Sugar maple (Acer saccharum) is an economically important tree species with defined elevational range limits.

Purpose of the Study:

• To investigate the roles of seed predation and soil properties in limiting sugar maple regeneration beyond its upper elevational range.
• To assess the impact of non-climatic factors on tree species' responses to climate change.

Main Methods:

• Field observations and experimental manipulations were used to assess sugar maple regeneration.
• Seed protection experiments tested the effect of predation on seedling establishment.
• Soil transplantation experiments evaluated the influence of soil properties and potential pathogens on regeneration.

Main Results:

• Seed predation was a primary factor limiting sugar maple regeneration beyond its established range.
• Experimental seed protection dramatically increased regeneration success beyond the range limit.
• Soil from beyond the range edge, when transplanted within the range, inhibited regeneration, suggesting soil-borne factors like fungal pathogens.

Conclusions:

• Non-climatic factors, specifically seed predation and soil conditions, are critical determinants of species range limits.
• These factors can create significant time lags in species' range shifts, even under favorable climatic conditions.
• Accurate prediction of climate change impacts requires integrating non-climatic factors into ecological models.