Climate change impacts on ecosystem functioning: evidence from an Empetrum heathland

Area of Science:

• Ecology
• Paleoecology
• Climate Change Science

Background:

• The influence of plants on ecosystem processes (e.g., nitrogen cycling, fire regimes) and their dependence on environmental conditions remain poorly understood.
• Investigating plant-environment interactions is crucial for understanding ecosystem dynamics and resilience.

Purpose of the Study:

• To determine the functional relationships between Empetrum (crowberry) and Betula (birch) and millennial-scale changes in climate, fire, nitrogen cycling, and herbivory in an Irish heathland.
• To model plant-environment interactions using mechanistic models and palaeoecological data.

Main Methods:

• Application of mechanistic models of plant-environment interactions.
• Analysis of palaeoecological time series data from an Irish heathland.
• Quantification of relationships between plant populations (Empetrum, Betula) and environmental factors (climate, fire, nitrogen, herbivores).

Main Results:

• Herbivory and fire preferentially impacted Betula, while Empetrum positively fed back on fire activity.
• Climate warming favored Betula expansion due to its higher temperature-dependent growth rate, leading to reduced fire activity and increased herbivory.
• Nitrogen cycling showed limited control by plant population dynamics.

Conclusions:

• Differential responses of plant populations to warming can drive shifts to alternative community states with altered ecosystem functioning.
• Self-reinforcing feedback mechanisms in plant communities may be vulnerable to climate warming, especially in arctic regions.
• Understanding plant-climate feedbacks is essential for predicting future ecosystem changes.