Litter decomposition under drought related with litter and decomposer diversity

Litter decomposition is a crucial ecosystem process that driven carbon and nutrient cycling, which can be determined by the diversity of biota that involved in decomposition process. Forest ecosystems at globally have been or being expected to experience drought stress and cause dieback, consequently may lead losses of tree species and soil biota. However, how projected drought affect litter decomposition and its relationship with biodiversity is less understood. We hypothesize that 1) drought depressed the activity of soil biota and retard litter decomposition, while biodiversity loss at both plant and soil organism levels exacerbated the drought induced retarding of litter decomposition; 2) soil biota interaction or the top down control of ecosystem process can be relieved under drought stress. In our study, throughfall reduction experiments were conducted in five locations representing different forest types (i.e., temperate broadleaf-Korean pine mixed forest, warm-temperate oak forest, subtropical bamboo forest, south subtropical evergreen forest, tropical rainforest) along a climate gradient in China. In each location, leaf litter from 4 common native plants and 11 mixtures of these litter types were enclosed in three types of nylon mesh screens litterbags, and were placed in the field of throughfall reduction and control treatments replicated five times. Different combination of litter types represent diversity of litters, and mesh size of litterbags represent diversity of functional group of soil biota (i.e., microorganism, medium-sized fauna, large-bodied fauna) participate into decomposition. The litterbags were incubated in situ for a period of time and were collected, all litter samples were separated into the constituent species immediately after litter retrieval, mass loss, C and N loss of each sample was determined. Thereby the hypothesizes can be testified.