Invasive alien species conquer water bodies in Bulgaria

Invasive alien species are already conquering water bodies in Bulgaria, it became clear at an online webinar on Friday about aquatic invasive alien species on the occasion of World Water Day, which was on March 22. The best way to deal with them is to prevent them, because they colonize entire reservoirs when they appear, explained Dimitrina Boteva, grassland habitat coordinator at the Information and Nature Protection Foundation. With global warming, they are expected to become an increasing threat to Bulgaria as well. Currently, of all foreign invasive species, 12 are distributed in the reservoirs of Europe, and in Bulgaria there are currently two main species - natalum plague and Canadian plague. It is a perennial herbaceous plant, completely submerged in water and comes from North America as a result of trade in live aquarium plants, in our country the species was discovered in 2002.

Batak Dam is obsessed with nutalium water plague, which has displaced the traditional grass vegetation in the dam, said Valeri Georgiev, a biologist at the Institute of Biodiversity and Ecosystem Research at the Bulgarian Academy of Sciences. For this reason, the dam is swampy and instead of a beautiful place for sunbathing and tourism, it is becoming more and more permanently a swamp. The load of nitrates and phosphates, various nutrients from hotels and restaurants around the dam increase the spread of Nutali plague, experts say.

Once spread, fighting them is very difficult and expensive

Removing it becomes extremely difficult and very expensive. The struggle can take at least five years if all the necessary measures are taken constantly. For example, it is easiest to remove when drying after water withdrawal. If it is not cleared at high tide, it easily spreads again and the shores become increasingly muddy. The point is that with birds and not well cleaned rods can easily pass from one dam to another. Only weeks ago, Bulgarian scientists also established the presence of a large lagarosyphon, it is possible that this will be the next foreign invasive species to start spreading rapidly. Unfortunately, it could be years before scientists discover these invasive species, experts say.

Valeri Georgiev compared this scourge to the coronavirus. It is best that we did not allow it to spread, because dealing with it costs us much more. "Unfortunately, there is no undo in nature," he stressed.

Aquatic invasive species are the most difficult to control, difficult to treat chemically, because the chemicals would easily spread throughout the reservoir, said Vladimir Vladimirov of the Institute of Biodiversity and Ecosystem Research.

In Bulgaria we have no control plans, it is important not to throw them into nature

The EU regulation for protection against invasive species is not yet a fact in Bulgaria, but also in many other countries. Currently, the most important thing is to identify all the routes through which these species enter and to prepare control and monitoring plans. Most often, their entry occurs with the dumping in nature of ornamental plants in the decoration of ornamental pools of water from gardens, parks in cities and business complexes, in the yard of houses or in aquariums in public and private spaces. Bulgaria has not yet developed a management and control plan for this road, Vladimirov explained. The most important thing for people to remember is that they can best dispose of them in household containers, hand them over to composting plants, but in no case should they fall freely into the environment or into water bodies.

"Not everything that is green and photosynthetic is useful and harmless, and we must destroy this illusion in every way," said project manager Svetlana Aladjem.

The problems that aquatic invasive species create for us

Aquatic invasive species block traffic on lakes, rivers and navigable canals. They clog drainage systems, pumping stations and sluices and can even lead to floods. They form dense floating carpets that block the outflow of water. Aquatic invasive alien species damage hydroelectric facilities and measuring stations, reduce yields in fisheries, reduce yields in rice paddies. They degrade water quality a prerequisite for the development of mosquitoes, parasitic flatworms and snails, which are vectors of disease. Their intensive penetration limits the use of water pools for recreation (swimming, swimming, rowing) and fishing.

In the Netherlands, in 2000, the total amount for the control of Hydrocotyle ranunculoides was around EUR 1 000 000, and in 2007 an additional EUR 1 800 000 was spent above the planned amount.

The list of the European Union includes many species that are excluded very beautiful decorative, but left in nature can cause great damage. Such are the great flower ludwigia, aquatic perennial, water hyacinth, Carolinian cabomba, buttercup hydrocotyl, alternator, giant floating watering can, Senegalese tea.

Plants colonizers of reservoirs: important to remember

All reservoirs, especially with slow-flowing and stagnant waters in Bulgaria are potentially at risk of future colonization by aquatic invasive alien species. Free trade in these species as aquarium plants, incl. over the Internet, contributes to widespread distribution and easy accessibility.

Most often they fall into natural conditions through amateur aquarists or when flooding ornamental ponds during floods.

The ways of further spread are by transporting parts of the plants from waterfowl, water currents, boats and fishing tackle.

Monitoring is needed for the timely detection of such species, with special attention to the Danube River - one of the most common routes for the entry of invasive plants in Bulgaria.

And are they valuable as a source of biomass

This idea is interesting because it is a good solution to the problem of their uncontrolled distribution, but also an opportunity to use invasive species as a resource for biomass, said Vladimir Vladimirov in response to a question from 3eNews. Studies are being conducted on the value of the biologically active substances of invasive species for treatment. It is even easier to study the issue of their use as biomass, the problem is that dry biomass is very small in volume. Every investor is looking for an easier way to collect more raw material. In practice, these arguments make such a decision almost impossible. A lot of money is required and the economic profit is almost non-existent.

Invasive alien species threaten local biodiversity, human health and cause allergies, asthma, skin diseases), damage the economy, lead to loss of agricultural production.

Every year, more than € 12 billion is spent in the EU to control invasive alien species

There are about 12,000 alien species in Europe, of which about 6,500 are plants. About 10% of them are invasive. In Bulgaria, over 60 species of higher plants have been identified as invasive. Every year, more than € 12 billion is spent in the EU to control invasive alien species.

The project for invasive alien species is implemented under the LIFE program and the Enterprise for Management of Environmental Protection Activities (EMEPA) of the Information and Nature Protection Foundation and the Press Center of the Ministry of Environment and Water to promote this topic so unknown to the general public.