Modeling Wildfire Effects on Ecosystem Services in two Disparate California Watersheds and Communities

Area of Science:

• Environmental Science
• Ecology
• Conservation Biology

Background:

• Extreme wildfire events pose significant threats to watershed health and human well-being.
• Understanding the impacts of wildfires on ecosystem services is crucial for environmental management.
• The distributional effects of wildfire impacts on ecosystem services across human communities are understudied.

Purpose of the Study:

• To assess the impacts of 2017 California wildfires on water provisioning, soil loss, carbon sequestration, and nutrient delivery.
• To analyze how these wildfires affected ecosystem services in two specific watersheds and their communities.
• To determine if wildfire impacts exacerbated pre-existing distributional differences in ecosystem services across communities.

Main Methods:

• Utilized the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model to simulate ecosystem service changes.
• Employed regression analyses to compare pre- and post-fire ecosystem service distributions.
• Quantified changes in biomass, carbon storage, water yield, and nutrient export.

Main Results:

• Biomass decreased in forest, woodland, and chaparral; grassland increased post-fire.
• Significant carbon loss observed: ~200,000 tons (Mark West) and ~160,000 tons (Southern California).
• Water yield increased by 5% and 42%; phosphorus and nitrogen export also rose post-fire.

Conclusions:

• Wildfires significantly altered vegetation composition and key ecosystem services.
• While pre-fire ecosystem service distribution varied among communities, post-fire conditions did not worsen these disparities.
• Findings highlight the complex impacts of wildfires on natural resources and human settlements.