Mesofauna community influences litter chemical trajectories during early-stage litter decay

Decomposition of organic material is moderated by both litter chemistry and decomposer communities. Chemical alteration of the litter occurs throughout decomposition, yet our understanding of the nature of chemical change during decomposition is limited, particularly beyond carbon (C) and nitrogen (N). The decomposer food web likely interacts with these chemical changes in their basal resource to alter the trajectories of chemical changes during decay. To investigate how decomposer mesofauna influence patterns of litter chemical change throughout early stages of decay, we tracked mass loss, macro- and micronutrient elements, and fiber chemistry dynamics in Arizona sycamore (Platanus wrightii) leaves decomposed in a mesocosm of optimal decay conditions in a biotically diverse compost pile. By using litterbags of two different mesh sizes to manipulate the mesofauna gaining access to the litter, we identify how the complexity of the soil mesofauna community changes the trajectory of litter chemistry, beyond the typical focus on mass loss and N dynamics. Counter to many examples in the literature, the more abundant and complex arthropod community slowed mass loss and enhanced nutrient immobilization, perhaps due to competition and grazing pressure on the microbial community to immobilize N, P, and Ca sooner from the surrounding compost.