Canopy opening increases leaf‐shredding arthropods and nutrient mineralization but not mass loss in wet tropical forest

Abstract

Hurricanes alter forest habitat by opening the canopy and depositing fresh wood and leaves. The objectives of this study were to evaluate the effects of hurricane and drought‐driven changes to forests on green litter decomposition, invertebrate communities, and nutrient mineralization over a short period (6 months) after disturbance. We used three complete replicated blocks with two canopy treatments: control and trim + detritus. Green leaves were enclosed in litterbags of three different mesh sizes to determine the effect of soil fauna of varying body sizes. Litterbags were retrieved from the field after 21, 35, 84, and 168 days and transported to the laboratory in individually sealed plastic bags. We extracted and identified invertebrates, measured leached and mineralized litter nutrients using ion resin membranes placed for 1 week under the leaves inside the litterbags, and determined litter mass loss. Additional resin membranes were placed in the lowest litter layer above the mineral soil. The number of arthropod taxonomic groups and nutrient mineralization differed significantly between control and trim + detritus. Regardless of mesh size, bags in control plots had consistently higher invertebrate richness than in trim + detritus plots. Nitrogen mineralization and phosphorous mineralization were significantly higher in trim + detritus in large mesh size, and decomposer arthropod abundance was highest in large‐sized mesh bags. These data suggest that within functional categories, variations in feeding behavior among arthropod orders may affect the release of nutrients from organic matter. Percent mass loss did not differ between canopy treatments or litterbag mesh sizes, but instead decreased during drought. Invertebrate composition, but not abundance, differed significantly between canopy treatments with greater dominance by shredders (Lepidoptera and Diptera larvae) in trim + detritus, which corresponded to higher rates of nutrient mineralization from green leaves. These results suggest that regional drought dominated the mesoclimate surpassing any microclimate variation in response to canopy treatments. Since mass loss did not differ between canopy treatments or litterbag mesh sizes, our results suggest that differences in short‐term nutrient fluxes from green litter are mostly related to changes in the litter invertebrate food web rather than rates of decomposition.

Unraveling the Effects of Hurricane Maria on the Abundance and Composition of Harvestmen (Arachnida: Opiliones) Species Along an Elevational Gradient in Puerto Rico

“…These investigators lumped Opiliones and Araneae together for analysis, limiting our ability to tease apart any effects on harvestmen (Richardson et al 2010). In a follow up study, canopy trimming plus litter deposition led to increased abundance of shredders – lepidopteran and dipteran larvae, and these plots also saw increased nutrient remineralization rates (Moreno et al 2021). Likewise, canopy arthropods showed idiosyncratic responses to simulated hurricane damage, with initial increases observed for sap-sucking Hemiptera and detritivores, and longer term increases observed for a tree cricket and two spider species (Schowater et al 2017; Schowater 2017).…”

A Preconditioning Paradox: Contrasting Effects of Initial Phyllosphere and Early Leaf Decomposer Microfungi on Subsequent Colonization by Leaf Decomposing Non-Unit-Restricted Basidiomycetes

“…Osono [10] showed in a microcosm experiment that soluble carbohydrates had the largest decrease in chemical constituents during 8 weeks of preconditioning by Xylaria and Ascochyta, but only a slight decrease in percent N and no consistent pattern in percent lignin or total carbohydrate. In a field experiment at our site in tropical lower montane wet forest of Puerto Rico, leaching losses of N, P and K from leaf litter are high during the first 5 weeks of exposure [28], especially in the absence of basidiomycete fungi that recycle nutrients from lower to upper litter layers [13,28]. We hypothesize that leaching of mineral nutrients and decreases in soluble carbohydrates during preconditioning may be responsible for decreasing connectivity by basidiomycete white-rot fungi and decreasing mass loss based on nutrient leaching data from our site [28] and carbohydrate analyses in Japan by Osono [10].…”

Determining the Growing Potential of Jatropha curcas and Pongamia pinnata under Various Water Regimes

“…Moreno et al (2022) to check the variation among species and within the treatments using IBM Statistical Package (SPSS 20).…”