Importance of tussocks in supporting plant diversity in Carex schmidtii Meinsh. wetlands

Abstract

Tussocks created by Carex schmidtii in sedge meadows may be able to support biodiversity because of their structural complexity. Concerns about diversity loss and the potential to restore species-rich tussocks led us to investigate how tussocks foster high species richness and affect composition. We investigated vegetation in paired plots on and between tussocks of C. schmidtii, and measured environmental factors on and between tussocks. In all, 79 taxa were found in the sedge meadows. Species richness was higher on rather than between tussocks. During the growing season, the tops of tussocks were above the water level, whereas the area between tussocks was flooded. Soil temperature, organic carbon, soil total P and litter depth were higher on rather than between tussocks. Soil water content and soil total N were lower on than between tussocks. Species richness on tussocks increased with increasing tussock basal area, height and surface area. Based on canonical correspondence analysis, plant composition was mostly related to field water depth, organic carbon and tussock basal area. We conclude that tussocks enhance species richness by increasing surface area, and support a diversity of co-occurring species by creating at least two distinct microhabitats.