Does a Widespread Species Have a Higher Competition Ability Than an Endemic Species? A Case Study in the Dongting Lake Wetlands

Abstract

This study aimed to compare the competition abilities of Phragmites australis (PA), a widespread species, and Triarrhena lutarioriparia (TL), an endemic species, in the Dongting Lake wetlands. Field monitoring indicated that during flooding, the two plant species showed decreased survival percentage, which did not differ noticeably between them. Control experiment indicated that PA exhibited higher survival percentage than TL. In the field monitoring, PA showed higher aboveground biomass before flooding and higher relative elongation rate, whereas TL showed higher aboveground biomass after flooding and higher relative growth rate. However, in the control experiment, plant biomass, relative growth rate, and relative elongation rate were not obviously different between the two species, and PA showed higher competition ability than TL in the early stage and lower competition ability than those of TL in the middle and later stages. The relative yield total in both the field monitoring and control experiment were greater than one, indicating that the two plant species occupied different niches. Compared to TL, PA had higher competition ability in non-submergence habitat and lower competition ability in water submergence habitat. Niche difference between the two species enabled their coexistence in the Dongting Lake wetlands under the influence of seasonal flooding.