Spatial distribution of soil organic carbon and total nitrogen in disturbed Carex tussock wetland

Abstract

Disturbance affects the ecological structure and function of wetland ecosystems by altering plant and soil properties. To identify the response of soil carbon and nitrogen to wetland disturbance, this study was conducted in three disturbed and two reference Carex tussock wetlands in Momoge National Natural Reserve, China. The content and stocks of soil organic carbon (SOC) and total nitrogen (TN) were determined to investigate the effects of disturbance on their spatial distribution. Generally, SOC and TN content and stocks gradually decreased with increasing soil depth except for in reference tussock wetlands that had an accumulation peak at 11–20 cm. In disturbed tussock wetlands, a significantly higher SOC content was observed in the top 10 cm of soil, while in disturbed and reference wetlands, no significant differences were found in SOC content and stocks, or in TN levels, in deep soil. Additionally, soil organic carbon and nitrogen were significantly correlated with soil water content (SWC), bulk density, soil porosity, and soil respiration (SR). Redundancy analysis revealed that SWC and SR were major determinants of soil carbon and nitrogen. These findings clarified the dynamic changes of soil carbon and nitrogen of disturbed wetland, which is highly significant for accurate estimation of wetland carbon and nitrogen reserves.