Compositional Acclimation Can Lessen Tropical Forest Change in Response to Increasing Lightning Frequency: Insights...

Area of Science:

• Ecology
• Forestry
• Climate Change Science

Background:

• Tropical forests face increasing lightning frequency, a major driver of tree mortality.
• The ecological implications of escalating lightning events on forest dynamics remain largely uncertain.

Purpose of the Study:

• To develop and implement a species- and spatially explicit model of lightning impacts on tropical forest dynamics.
• To assess the sensitivity of forest aboveground biomass (AGB) and composition to changes in lightning frequency.

Main Methods:

• A mechanistic forest dynamics model was enhanced with a species- and spatially explicit lightning module.
• The model was calibrated and validated using observational data from a Panamanian tropical forest.
• Simulations were run to evaluate forest responses under varying lightning frequencies.

Main Results:

• The lightning-enabled model accurately simulated observed aboveground biomass (AGB), carbon flux, and stem densities.
• Increasing lightning frequency reduced overall AGB, but this effect was moderated by species-specific lightning tolerances.
• Forest composition shifted, with lightning-tolerant species increasing in AGB, and the impact of lightning on AGB saturated at high frequencies.

Conclusions:

• Empirically informed lightning modeling captures contemporary forest impacts.
• Changes in lightning frequency will alter forest AGB, species composition, and structure.
• Tropical forests can partially acclimate to increased lightning through compositional shifts, highlighting the need for lightning in global ecosystem models.