Submerged plant is one of the most vital primary producers in shallow freshwaters, which greatly influence the stability of freshwater ecosystem. A good understanding of species-genetic diversity correlation (SGDC) between the species diversity (SD) of submerged macrophyte communities and the genetic diversity (GD) of dominant submerged macrophyte is beneficial to develop reasonable management or restoration strategies.   

Researchers from Wuhan Botanical Garden, Chinese Academy of Sciences and Tibet University, investigated the SD of submerged macrophyte communities and GD of the dominant submerged plant Myriophyllum spicatum in the conserved and disturbed water areas of the Honghu Lake, China.   

For M. spicatum, the two areas showed similar level of GD because of its high gene flow within the lake. For communities, higher level of biomass was detected in the conserved area where grass-collecting was prohibited. Higher SD was found in the disturbed area, which was explained by the bare lands that caused by excessive plant harvesting, which could accept more different plant propagules or seeds. No SGDC was found in both two areas, which resulted from the convenient exchanges of species and genes within the lake. Moreover, SD of the communities had a faster response to disturbance compared with GD of M. spicatum, which also resulted in no SGDC. 

Results enlighten that both SD and GD should be considered during the conservation process of the Honghu Lake. The conserved area should be enlarged to serve a stable supply of species and genes for the disturbed area. Seedlings can be replanted to the lake for GD maintaining. Finally, government supervision should be strengthened, with monitoring aquatic plant diversity regularly and controlling pollution and excessive collection.   

Research was funded by the Talent Program of Wuhan Botanical Garden of the Chinese Academy of Sciences and the High-level Talent Training Program of Tibet University. The research has been published in Global Ecology and Conservation entitled “Contrasting relationships between genetic diversity and species diversity in conserved and disturbed submerged macrophyte communities of Honghu Lake, a typical freshwater lake of Yangtze River Basin”.  

Location of the 25 sample sites for M. spicatum in disturbed and conserved areas of Honghu Lake. (a) The submerged plant community in conserved area; (b) People were harvesting submerged plants in disturbed area (Image by FAN Xiangrong)