Assessing the influence of the ecological restoration project on the submerged aquatic vegetation in the Baiyangdian Lake, northern China

Submerged aquatic vegetation (SAV) is a key indicator for the restoration of wetland water environments and aquatic ecosystems. In this paper, SAV life history information was used to identify and analyze the spatial distribution of dominant SAV species in Baiyangdian Lake from 2017 to 2021 with Sentinel-2 image data, during the implementation of an ecological restoration project. The results show that: (1) The SWIR1_NIR index can achieve significantly accurate identification of SAV, with an accuracy of more than 88%. Combining life history features enabled researchers to distinguish the dominant SAV species with a classification accuracy of 68.75% and Kappa coefficient of 0.64. (2) The ecological restoration project did not significantly affect the spatial distribution of SAV; the SAV was still distributed in the northern, northwestern, southwestern, and shallow coastal areas of the lake. (3) Annually, dominant SAV species area in Baiyangdian Lake varied with the season. (4) Inter-annually, the overall distribution area of SAV in Baiyangdian Lake initially decreased and then increased. The results of this study are useful for the dredging and pollution control project of Baiyangdian Lake, and provide a scientific basis for the subsequent comprehensive treatment of SAV in the lake through multiple measures.