Dynamics of restoration of higher aquatic and semi-aquatic vegetation of Lake Manzherokskoye after its dredging in 2018

Abstract

The generalized retrospective and modern data represent dynamics of aquatic and semi-aquatic vegetation of Lake Manzherokskoye in recent years. It is shown that before implementation of the dredging works, the aquatic vegetation of Lake Manzherokskoye was distinguished by high species and coenotic diversity. However, the state of the water chestnut population worsened by 2007, as compared to the 1970s. Dredging caused a drastic decline in species and coenotic diversity of aquatic and semi-aquatic vegetation. For instance, species diversity of vascular plants (hydro- and helophytes) reduced from 25 to 12 species, while coenotic one – from 10 to 3 associations. Previously extensive thickets of water lily Nymphaea candida completely disappeared. In the first years after dredging, a rapid restoration of the macrophyte component of the aquatic ecosystem of Lake Manzherokskoye occurred, i.e. a drastic increase in species and coenotic diversity. In 2018–2022, species diversity of hydro- and helophytes increased from 12 to 24 species, and coenotic diversity – from 3 to 12 associations. Though the water chestnut population had recovered by 2022, today Lake Manzherokskoye remains the only reservoir in the Republic of Altai where the unique population Trapa pectinata exists. Thus, the lake should be preserved as a special protected natural area. Along with water chestnut, conservation of rare species of the floating mats (Sparganium subglobosum and S. glomeratum) is also of great importance.

Keywords

• republic of altai
• macrophytes
• flora
• species diversity