Growth of Carex Tussocks as a Response of Flooding Depth and Tussock Patterning and Size in Temperate Sedge Wetland, Northeast China

Abstract

Tussock swamp meadow, as a typical wetland in Northeast China, is governed by hydrological variations. Understanding the responses of tussocks to environment factors would help in advancing the management, protection and restoration of tussock sedge wetlands. We investigated ecological characteristics of tussocks in coverage, species height and above-biomass along a flooding gradient. Tussock patterning and hummock size were also recorded to identify the mechanisms of self-organization in tussock swamp meadow. Results showed that sampling sites and species had no significant effects on tussock ecological characteristics. Species coverage, species height and biomass were moderately related to flooding depth. The fittings based on Gauss model showed that the optimum flooding depth and flooding proportion for tussock biomass in critical growth period are 11.2 cm and 29.6%, respectively. Species coverage and above-biomass increased with increasing tussock density. Relationships between above-biomass and hummock size accorded with Gauss curve. Linear mixed-effect models indicated that flooding proportion, tussock density and hummock height exert great influences on the growth of tussocks. Results help to advance our understanding of the tussocks’ responses to environmental factors and the mechanisms of self-organization in tussock sedge wetlands.