Wetland area identification and waterbird protection management in consideration of lake topography and water level change

Abstract

Dongting Lake Wetlands are a key waterbird habitat. Wetland area and biomass growth are the two primary factors that influence the lives of waterbirds. Lake topography and water level changes significantly influence wetland area and biomass growth processes. However, to date, no study has quantified the associations of spatial-temporal patterns of wetland area changes and wetland plant biomass growth processes with lake topography and water level changes. Therefore, the land use-water level change simulation model is established to provide a simulation platform for spatial-temporal simulation of wetlands and plants biomass to provide support for the protection and management of wetlands and waterbirds. Dongting Lake, which is the second largest freshwater lake in China and an important habitat for migratory birds, is adopted as the study region. The influence of the Three Gorges Project on Dongting Lake water levels and wetlands is revealed through model simulation. After construction of the three Gorges Project, the highest water level value decreased 0.18 m, and the lowest water level value increased from 20.56 m to 21.11 m. The spatial-temporal patterns of wetland area and plant biomass growth were accurately calculated. The results suggest that the water level of the three Gorges Project can be maintained at a relatively high level from 167 m to 175 m, confirming the low and safe water level in Dongting Lake. The temporal water level adjustment frequency of the three Gorges Project should be further assessed in future research. The simulation model and the research results could provide a significant tool for wetland conservation and waterbird protection.