Иво Данчев


Restoration of Ruppia maritima in Atanasovsko lake

Aug. 25, 2020
Ruppia transfer
A pilot program for Bulgaria for recolonization of Ruppia maritima in coastal lagoons has been launched. This is a typical and very important species for the ecosystem and affects the water quality of the habitat. For many years, Ruppia was considered extinct from Atanasovsko Lake, but in 2016 a limited presence was found in the coastal parts of North Lake. This species is dependent on the salinity of the waters and its distribution is suppressed when it increases, especially in the conditions of salt production.

That is why the LIFE project "Lagoon of Life" planned to improve its population and expand its distribution in several more basins in this part of the lagoon. In 2019, studies of the ecological requirements of the sea rupee in the conditions of Atanasovsko Lake were conducted and the appropriate basins for recolonization were determined. Attempts to restore this species to other coastal lagoons, such as Venice, the British Isles, and Florida, have been studied. The methods for restoration are vegetative or seed propagation, as for the conditions of Atanasovsko Lake - the muddy bottom substrate and the shallow depth of the water, the vegetative method is more suitable - transfer of whole plants in the flowering phase.

In 2020, Ruppia's population in Atanasovsko Lake has completely disappeared, probably due to the increased turbidity of the waters. Therefore, it was necessary to extract propagating material from the nearby Pomorie Lake, where this species is widespread in the coastal lagoon. Currently, the species is in the maximum phase of flowering and fruiting, which will probably favor its recovery in Atanasovsko Lake, complementing the effect of vegetative propagation.

Two actions were carried out and about 4000 plants were collected, which were transferred and planted in a pool with suitable conditions in the northern part of Atanasovsko Lake. Planting is done in tufts of 20-30 plants, located a few meters from the shore of the pool at a certain distance. The goal is for the plants to be completely submerged, regardless of water level fluctuations. The plants are expected to take root successfully to form shoots (stalks) that will connect the individual tufts in a continuous dense colony. We hope that many of the thousands of seeds carried with the plants will germinate and thus support the recovery process.

In the coming months, the actions for the transfer of plants between Pomorie and Atanasovsko lakes will continue. The process of intercepting the planted tufts in the designated pools will be monitored, which will be strengthened if necessary. We expect the restoration of the sea rupee in Atanasovsko Lake to increase its conservation value and to have a positive impact on the quality of the waters in the lake, as well as the lake inhabitants that are connected in this plant species - macroinvertebrates, fish and ducks.

The activities for recolonization of the rupee, as well as the activities for the Lagoon of Life project, are coordinated by the Ministry of Environment and Water, according to the country's legislation.

Salt factory
Together 21
Life programme
Natura 2000