Increased fire severity alters initial vegetation regeneration across Calluna-dominated ecosystems

Area of Science:

• Ecology
• Fire Ecology
• Conservation Biology

Background:

• Calluna vulgaris habitats provide essential ecosystem services and are vital for conservation.
• Climate change is intensifying wildfire regimes, particularly through increased summer droughts.
• Altered fire regimes can significantly impact plant community composition and ecosystem function in these habitats.

Purpose of the Study:

• To investigate the effect of fire severity on plant community composition in Calluna vulgaris-dominated habitats.
• To simulate drought conditions preceding experimental burns to mimic future wildfire scenarios.
• To provide insights for land managers regarding prescribed burning for conservation objectives.

Main Methods:

• Experimental burns were conducted at two Calluna-dominated sites (raised bog and heathland) after simulating drought using rain-out shelters.
• Species abundance was analyzed approximately 16 months post-fire.
• Burn severity was quantified by measuring fire-induced soil heating.

Main Results:

• Fire severity was a key driver of community composition at both study sites.
• Higher fire severity promoted the abundance of ericoids, graminoids, and acrocarpous mosses, while decreasing pleurocarpous mosses.
• No significant difference in regeneration of Sphagnum capillifolium and Eriophorum vaginatum was observed with varying fire severity at the raised bog.
• Species and plant functional type beta-diversity increased post-fire, with similar levels across different fire severities.

Conclusions:

• Fire severity is a critical factor influencing the recovery and composition of Calluna vulgaris plant communities.
• Projected changes in fire regimes due to climate change necessitate careful consideration of burn severity for effective land management.
• Findings support land managers in selecting appropriate burning conditions to achieve specific management goals in Calluna habitats.