Soil phosphorus (P) negatively moderated the pantropical litterfall resistance to cyclones: A 100mg P/kg increase in soil P corresponds to a ~35% decrease in resistance.
Tropical cyclone regimes are shifting with climate change. In 2020, tropical cyclones affected 36 million people and caused $56 billion in damages globally. 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 P in mediating forest litterfall (flux of dead plant material from the canopy to the forest floor) resistance (ability to withstand change) and resilience (capacity to return to pre-cyclone condition) to 22 tropical cyclones. Results showed that soil P negatively moderated the pantropical litterfall resistance to cyclones. As soil P increased by 100 mg P/kg, resistance decreased by 32% to 38%.
Our results suggest that soil P will partially determine the pantropical forest litterfall resistance and resilience in the face of intensifying cyclone disturbance. This study is the first to document the pantropical role of phosphorus as a factor mediating tropical forest responses to cyclones. Litterfall mass and nutrient pulses caused by cyclones both respond and contribute to resource heterogeneity that can affect species regeneration, growth, and competitive interactions. Additional research can test how plant functional groups and species across pantropical forest ecosystems differ in their resistance and resilience to cyclones to represent cyclone disturbance responses in predictive modeling.
While the influence of tropical cyclone frequency and intensity on the structure and function of tropical forests have 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-phosphorus (P) soils is more resistant and less resilient to cyclones. We conducted a meta-analysis to investigate the pantropical importance of total soil P in mediating forest litterfall resistance and resilience to 22 tropical cyclones. We evaluated cyclone-induced and post-cyclone litterfall mass (g/m 2 /day), and P and nitrogen (N) fluxes (mg/m 2 /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/m 2 /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, our 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 ELM-FATES predictions against pantropical ground data.
Contact: Barbara Bomfim, Postdoctoral researcher NGEE-Tropics, Lawrence Berkeley National Laboratory, firstname.lastname@example.org
This research was supported as part of the Next Generation Ecosystem Experiments-Tropics (NGEE), funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research. ORNL is managed by UT-Battelle, LLC, for the DOE. This research utilized data from Luquillo Long-Term Ecological Research (LTER) Program which is currently supported by NSF to the Institute for Tropical Ecosystem Studies, University of Puerto Rico, and to the International Institute of Tropical Forestry USDA Forest Service.
Bomfim, B., Walker, A.P., McDowell, W.H., Zimmerman, J.K., Feng, Y., Kueppers, L.M., Linking soil phosphorus with forest litterfall resistance and resilience to cyclone disturbance: a pantropical meta‐analysis. Global Change Biology gcb.16223 (2022) https://doi.org/10.1111/gcb.16223