Soil cellulase activity and fungal community responses to wetland degradation in the Zoige Plateau, China

Four soil types (peat, marsh, meadow, and sandy) in the Zoige Plateau of China are associated with the severity of wetland degradation. The effects of wetland degradation on the structure and abundance of fungal communities and cellulase activity were assessed in these 4 soil types at 3 depths using DGGE (Denatured Gradient Gel Electrophoresis), qPCR (Quantitative Real-time PCR), and 3,5-dinitrosalicylic acid assays. Cellulase activity and abundance of the fungal community declined in parallel to the level of wetland degradation (from least to most disturbed). DGGE analysis indicated a major shift in composition of fungal communities among the 4 soil types consistent with the level of degradation. Water content (WC), organic carbon (OC), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), and available phosphorus (AP) were strongly correlated with cellulase activity and the structure and abundance of the fungal community. The results indicate that soil physicochemical properties (WC, OC, TN, TP, AN, and AP), cellulase activity, and diversity and abundance of fungal communities are sensitive indicators of the relative level of wetland degradation. WC was the major factor involved in Zoige wetland degradation and lower WC levels contributed to declines in the abundance and diversity of the fungal community and reduction in cellulase activity.