Biome-Specific Responses of GOSIF Gross Primary Productivity to Wildfires in South America

The frequency and severity of wildfire events have increased significantly due to global warming, further disturbing the terrestrial ecosystem carbon cycle. Observations over the past several decades have shown that wildfires cause a dramatic decline in vegetation productivity. However, the biome-specific responses of gross primary productivity (GPP) to wildfires remain uncleared. Here, structural equation modeling was employed to analyze the mechanisms underlying wildfires on GPP using moderate resolution imaging spectroradiometer (MODIS) satellite data along with climatic and vegetation information in South America over a 20-year period from 2001 to 2020. We observed the biome-specific responses in GPP to wildfires among vegetation types. In forest ecosystems, increased burning severity led to substantial reductions in GPP directly, whereas in savanna ecosystems, wildfires indirectly regulated GPP by altering soil moisture. In grasslands, burned area rather than wildfire severity dominated the decrease in GPP. These findings emphasize the crucial role of vegetation types in exploring the effects of wildfires on the terrestrial ecosystem carbon cycle.