The home-field advantage of litter decomposition in lake wetlands and the community characteristics of bacterial and eukaryotic decomposers

Purpose The home-field advantage (HFA) of litter decomposition is widespread in various terrestrial ecosystems, but whether it is present in wetland ecosystems and what the influencing factors are is less well-known. Here we conducted a 165-day transplanted litter decomposition experiment in a wetland ecosystem to explore the HFA effect and its relationships to litter quality and decomposer community structure. Methods Three types of litter (sedge, silvergrass, and reed leaves) were transplanted in the Poyang Lake Wetlands of China, and the decomposition rate was accessed by periodic recovery of the remained litter samples. The bacterial and eukaryotic decomposer communities were determined by the rRNA gene sequencing method. Extracellular enzyme activities from litters were continuously monitored during decomposition. Co-occurrence networks were constructed to identify the keystone taxa. Results We found that the HFA of litter decomposition was prevalent in wetlands, with home-field advantage for sedge and silvergrass litters, while home-field disadvantage for reed litter. The primary litter quality (especially TN and cellulose), enzymatic activity, and nutrient release pattern all affected the HFA effect. The most significant variation of decomposer community occurred among decay times, followed by litter types and decay sites. The difference in decomposer community composition among litters decreased with the decomposition time. The bacterial communities were significantly different among decay sites for all litters, while the eukaryotic communities were similar among decay sites until 165 days. The bacterial community was more sensitive to the HFA, while the eukaryotic community mainly contributed to the decomposition rate. Some habitat-specific decomposers contributed to the HFA, including Gammaproteobacteria, Alphaproteobacteria, Firmicutes, Ascomycota, Nematoda, and Ciliophora. The networks for litters with HFA had more nodes, more positive edges and keystone species than the litters without HFA. Conclusion The initial litter quality and decomposer community (mainly bacteria) collectively drive the HFA of litter decomposition in wetlands, and the network analysis may be used to predict the HFA during litter decomposition.