The Role of Microbial and Macroinvertebrate Communities on Early Leaf Decomposition Rates of the African Cycad

Abstract

ABSTRACT The slow decomposition of cycad leaf litter plays a unique role in carbon and nutrient cycling. This study explored early‐stage effects of micro, meso‐ and macroinvertebrate activity on decomposition rates of Encephalartos natalensis and Encephalartos villosus , with Sclerocarya birrea as a control. The litterbag technique was employed, where coarse (5 mm mesh size) bags that allowed for macroinvertebrate and microbial decomposition, and fine (0.025 mm mesh size) bags that only permitted microbial decomposition were used. To assess above‐ and belowground influences, litterbags were placed on the soil surface or buried under‐ground. A two‐way analysis of variance was performed to evaluate differences in decomposition rates among leaf species and placement conditions. Significant differences in decomposition rates were observed for leaf type. S. birrea decomposed significantly faster when compared to E. natalensis and E. villosus , regardless of macroinvertebrate exclusion. Leaf litter exposed to microbial, meso‐ and macroinvertebrate activity decomposed faster than litter exposed solely to microbial activity among all leaf species. Meso‐ and macroinvertebrates were found to enhance decomposition with microbial activity driving the early‐stage decomposition rate, though future research in the cycad species' natural habitats is recommended to explore environmental and seasonal effects.