Effects of warming on litter decomposition and fungal communities in lake wetlands

The impact of climate warming on the decomposition of wetland plant litter has received widespread attention. We used the litter bag method to compare and study the decomposition processes of three species of litter in the Nansi Lake wetland of China, Phragmites australis (Ph), Nelumbo nucifera (Ne) and Typha domingensis (Ty), and simulate the changes in the decomposition characteristics of litter and the structure of the fungal community under atmospheric warming (2.0 ± 0.5 °C ~ 4.0 ± 0.5 °C) using open-top chambers (OTCs). The results showed that increasing temperature significantly accelerated the decomposition process of the three species of litter and increased the beta and alpha diversities of the fungal communities at the class level. The fungal community co-occurrence network showed that the fungal community network associated with litter decomposition under warming conditions consisted mainly of symbiotic relationships, and the order of the average clustering coefficients of the three networks was 2.0 ± 0.5 °C (0.81) > 4.0 ± 0.5 °C (0.77) > control (0.57). Moderate warming increased the degree of positive correlation and clustering between fungi, thus accelerating the decomposition process of plant litter and affecting the carbon balance of wetland ecosystems.