The impacts of drought on the ecological niches of typical wetland plants in Poyang Lake, China

Poyang Lake wetland plays an important ecological service function. Frequent drought events have caused significant changes in the distribution pattern of wetland plants. This study analyzed the changes in the distribution elevation of wetland plants in Poyang Lake from 2000 to 2020, including the optimal elevation, and upper and lower limit elevations, and revealed the impacts of drought on the ecological niches of typical wetland plants. The results showed that the wetland plants were distributed in a regular strip pattern according to the elevation gradient. The Polygonum hydropiper-Phalaris arundinacea (PP), Carex cinerascens (Cc), Phragmites australis-Triarrhena lutarioriparia (PT), and Artemisia selengensis (As) communities were mainly distributed at elevations of 8.70-13.62 m, 10.35-14.99 m, 12.00-16.28 m, and 11.82-18.46 m, with optimal elevations of 11.16, 12.67, 14.14, and 15.14 m, respectively. Although the optimal elevations and upper limit elevations of four typical wetland plants exhibited different changing trends, their lower limit elevations showed the significant downward trends, especially for Cc and PP communities. Moreover, drought caused a varying degree of decrease (0.16-0.34 m) in the optimal elevations of four typical wetland plants, the upper and lower limit elevations of most wetland plants had also decreased in dry years.