Linking soil phosphorus with forest litterfall resistance and resilience to cyclone disturbance: A pantropical meta‐analysis

Abstract

While tropical cyclone regimes are shifting with climate change, the mechanisms underpinning the resistance (ability to withstand disturbance-induced change) and resilience (capacity to return to pre-disturbance reference) of tropical forest litterfall to cyclones remain largely unexplored pantropically. 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. A GAMM indicated that soil P, gale wind duration and time post-cyclone jointly moderate the short-term resilience of total litterfall, with the nature of the relationship between resilience and soil P contingent on time and wind duration. 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.

Combining field and remote sensing data to estimate forest canopy damage and recovery following tropical cyclones across tropical regions

“…Post-cyclone data were extracted as the mean from 1 to 16 d post-cyclone for each case (table 1). This controls for the temporal decrease in cyclone effects seen in most cyclone-affected sites, and is consistent with the period employed to calculate cyclone-induced changes in litterfall (Bomfim et al 2022). In addition, extracting data prior to phenological changes in forest vegetation is imperative for assessing short-to medium-term cyclone-induced effects (Peereman et al 2020).…”

“…As shown in table 1, some sites were affected more than once by a cyclone event, such as those in Taiwan. Bomfim et al (2022) also compiled soil, lithology, climate, biogeographic, and cyclone regime variables for each case, including site-specific total soil P concentrations. The case data compiled by Bomfim et al (2022) allowed for comparisons between the total litterfall mass flux, remote sensing-derived LAI and EVI, and site-specific soil, environmental, and cyclone regime variables (figure 1).…”

“…not considering seasonality) change in total litterfall (∆TL) and assessed its linear relationship with ∆LAI and ∆EVI. We used the pre-and post-cyclone litterfall means from Bomfim et al (2022), who found no difference between the cyclone-induced ∆TL calculated using annual versus seasonally adjusted pre-cyclone means. Therefore, in our study we used the annual ∆TL (log response ratio) as calculated in Bomfim et al (2022).…”

“…Because pantropical forest litterfall fluxes respond variably to tropical cyclones (Bomfim et al 2022), understanding the drivers of this variation will improve regional and pantropical extrapolation of cyclone impacts. Field studies have quantified changes in vegetation and vegetation indices in response to tropical cyclones (e.g.…”

“…Evidence from Australia suggests that plant species growing on high-P basalt soils had greater changes in LAI and higher branch breakage immediately after a cyclone than those growing on low-P schist soils (Gleason et al 2008). A recent pantropical meta-analysis of field-observed observations indicated that across 26 tropical forest sites affected by 22 tropical cyclones, cyclone-induced litterfall increased by 33%-38% for each 100 mg kg −1 increase in total soil P concentration (Bomfim et al 2022). However, it is not known whether the patterns seen across sites in litterfall can be detected remotely.…”