Linking Soil Phosphorus with the Resistance and Resilience of Forest Litterfall to Cyclone Disturbance: A Pantropical Meta-Analysis

The Science

Changing tropical cyclone regimes may lead to long-lasting effects on tropical forests under climate change. This pantropical meta-analysis investigated the importance of total soil phosphorus (P) in mediating forest litterfall resistance (ability to withstand change) and resilience (ability to return to pre-cyclone condition) during 22 tropical cyclones. Results showed that as soil P increased, litterfall resistance to cyclones decreased.

The Impact

This study by Next-Generation Ecosystem Experiments-Tropics (NGEE-Tropics) researchers is the first to document the pantropical role of soil P as a factor mediating tropical forest responses to cyclones. Litterfall mass and nutrient pulses caused by cyclones both respond and contribute to variability resource availability that can affect species regeneration, growth, and competitive interactions. Additional research can test how plants across pantropical forest ecosystems differ in their resistance and resilience to cyclones to better represent forest response to cyclone disturbance in predictive models.

Summary

While the influence of tropical cyclone frequency and intensity on the structure and function of tropical forests has been widely studied, much less attention has been given to the role of resource availability on the functional stability of tropical forests across the globe in the face of cyclone disturbance. Single-site studies in Australia and Hawaii suggest that litterfall on low-P soils is more resistant and less resilient to cyclones. Researchers conducted a meta-analysis to investigate the pantropical importance of total soil P in mediating forest litterfall resistance and resilience to 22 tropical cyclones. The researchers evaluated cyclone-induced and post-cyclone litterfall mass (g/m²/day), and P and nitrogen (N) fluxes (mg/m²/day) and concentrations (mg/g), all indicators of ecosystem function and essential for nutrient cycling.

Across 73 case studies in Australia, Guadeloupe, Hawaii, Mexico, Puerto Rico, and Taiwan, total litterfall mass flux increased from ~2.5 ± 0.3 to 22.5 ± 3 g/m²/day due to cyclones, with large variation among studies. Litterfall P and N fluxes post-cyclone represented ~5% and 10% of the average annual fluxes, respectively. Post-cyclone leaf litterfall N and P concentrations were 21.6 ± 1.2% and 58.6 ± 2.3% higher than pre-cyclone means. Mixed-effects models determined that soil P negatively moderated the pantropical litterfall resistance to cyclones, with a 100 mg P/kg increase in soil P corresponding to a 32% to 38% decrease in resistance. Based on 33% of the resistance case studies, total litterfall mass flux reached pre-disturbance levels within one year post-disturbance. Across pantropical forests observed to date, these results indicate that litterfall resistance and resilience in the face of intensifying cyclones will be partially determined by total soil P. This work will support benchmarking of E3SM Land Model – Functionally Assembled Terrestrial Ecosystem Simulator (ELM-FATES) predictions against pantropical ground data.

Principal Investigator

Barbara Bomfim
Lawrence Berkeley National Laboratory
[email protected]

Program Manager

Brian Benscoter
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
[email protected]

Funding

This research was supported as part of the Next-Generation Ecosystem Experiments-Tropics (NGEE-Tropics) and was funded by the Biological and Environmental Research (BER) Program within the U.S. Department of Energy’s (DOE) Office of Science. This research utilized data from Luquillo Long-Term Ecological Research (LTER) Program, which is currently supported by the National Science Foundation (NSF) to the Institute for Tropical Ecosystem Studies, University of Puerto Rico, and the International Institute of Tropical Forestry, USDA Forest Service.

References