1 Toomas Kukk (Institute of Zoology and Botany, Tartu) has given an overview of alien species in Estonian flora (book in Estonian “Eesti taimestik”, 1999). No special studies have been conducted concerning alien species.
Tõnu Ploompuu (Pedagogical University of Tallinn) has conducted a study about alien species in gardens of Tallinn. He has also a draft database of flora around railways and dumps (this database includs also information about alien species).
According to Estonian Teriological Society and Ornithological Society Estonia has fairly good overview about alien animal and bird species.
Although Estonia has some information about introduced fish species, there is a sharp lack of overview of alien aquatic species in Estonia. Some work has been done concerning couple of species (for example predatory cladoceran Cercopagis pengoi and polychaete Marenzelleria viridis).
Henn Ojaveer (Estonian Marine Institute) et al has prepeared a manuscript “The Baltic- a sea of invaders”, it will be submitted for publication in Canadian Journal of Fisheries and Aquatic Sciences. There is compiled data about alien species in Baltic sea.
2Alien species is not a separate issue in Estonian NBSAP. It is included to many issues: Fisheries, Border Control and Nature Conservation.
Fisheries: Necessary activities forseen in Action Plan for years 2000-2005:
Sanctions and penalty fines for introduction of alien species and forms,
Modernization of fish farming to avoid the escape of reared specimens,
A publication about alien species in Estonian waters, spread of alien species in Estonian water bodies and their impact on local ecosystems;
Nature Conservation: Necessary activities forseen in Action Plan for years 2000-2005:
Analysis of the ecological and economic influences of non-native species along with assessment of future distribution and possible control measures.
Fulfillment of CITES is to some extent connected to the issue of alien species. (Nethetheless, the border control in relation of species other than CITES species is very weak (possible problem for future: Pacifastacus leniusculus, see below).)
NBSAP does not cover all the issue of alien species!
As NBSAP is not yet approved by the Government, there is no money forseen for implementation of these activities!
3 There is a lack of systematic approach to the issue of alien species.
The risks of American mink (Mustela vison) (especially threats to native species European mink Mustela lutreola) is profoundly assessed by Tiit Maran (foundation Lutreola, Tallinn Zoo).
There are some information about risks of raccoon-dog (Nyztereutes procyonoides).
Several species of Acipenser sp. have been introduced to Esonian waterbodies during the time when Estonia belonged to USSR. Rainbow trout (Salmo gaidneri Richardson) and Acipenser sp are found in Estonian waters. These species give very seldom offspring in Estonia and ichtyologists say that these species are not problematic for native fauna/flora.
Studying of the alien aquatic species began in the second half on 80-ies, but there is scarce lack of financial resources. The fact that there is no control over the species in ballast waters of ships makes the situation more complicated.
A comprehensive study has been conducted by Marine Institute concerning Cercopagis pengoi and Marenzelleria viridis. The former originates from Pronto-Caspian region, first time found from Estonian waters in Baltic Sea in 1992. The latter originates from North-America, first time found from the Baltic Sea in 1985. Both of the species have caused decline of abundance of several native species and changes in marine ecosystem. No specific risk assessment has been conducted concerning these species.
According to Toomas Kukk (Institute of Zoology and Botany) there is little knowledge about the potential threats of alien species to native flora. The spread of alien species into native communities in Estonia is unsufficiently studied. There are couple of studies from the 30-ies about Impatiens parviflora and Elodea canadensis. I. parviflora and Chamomilla suveolens were initially grown in Tartu botanical garden and they escaped from there. Heracleum sosnowski has escaped from garden of Institute of Zoology and Botany and it is very widely spread now in Estonia. This species as well as Galega orientalis has caused many problems in many regions during last years. H. sosnowski could be dangerous to human health – it can cause blisters.
The most dangerous species are H. sosnowski, Galega orientalis, Petasites hybridus, Rosa rugosa, Elodea canadensis, Lactuca serriola, Lupinus polyphyllus, Saponaria officinalis and Sambucus racemosa.
4 Legal acts dealing with alien species:
Act on Protected Natural Objects and Act on Protection and Management of Fauna prohibit the release of any alien species to the territory of Estonia. Re-introduction of species can be undertaken on scientific bases and only after the issuance of the permit from the Ministry of the Environment. The same is established by the Fisheries Act in relation of any alien species of fish or other aquatic organisms and their fertilized roe.
The problem is that this scheme does not function in reality.
One example. There are couple of pheasant farms in Estonia. Hunters breed them and then release into the wood and hunt them later. Actually they should apply for a permit from Ministry of the Environment for that (as there is always a possibility that not all of the birds will be captured and some of them could stay to the woods) but until now no permits have been applied for.
5This is due to a lack of available case-studies.
6 Case studies:
About Mustela vison: Maran, T. 1991. Distribution of the European mink, Mustela lutreola, in
Estonia: A historical review. - Folia Theriol. Estonica 1:1-17.
Ojaveer, E. and Lumberg, A. 1995. On the role of Cercopagis pengoi (Ostroumov) in Pärnu bay and the NE part of the Gulf of Riga ecosystem. Proc. Estonian Acad. Sci. Biol. Ecol. 5: 20-25.
Kotta, J. and Kotta, I. 1998. Distribution and invasion ecology of Marenzelleria viridis in the Estonian coastal waters. Proc. Estonian Acad. Sci. Biol. Ecol. 47: 212-220.
Kotta, J., Orav., H. and Kotta, I. 1998. Distribution and filtration activity of the zebra mussel, Dreissena polymorpha, in the Gulf of Riga and Gulf of Finland. Proc. Estonian Acad. Sci. Biol. Ecol. 47: 32-41.
Ojaveer, H., Lankov, A., Eero, M., Kotta, J., Kotta, I. And Lumberg, A. 1999. Changes in the ecosystem of the Gulf of Riga from the 1970s to the 1990s. ICES Journal of Marine Science. 56: 33-40.
Kotta, J. 2000. First record of the talitrid amphipod Orcestia cavimana in the northern Baltic sea. Proc. Estonian Acad. Sci. Biol. Ecol, 49: 221-224.
Ojaveer, H., Simm, M., Lankov. A and Lumberg, A. 2000. Consequences of invasion of a predatory cladoceran. Raport for International Council for the Exploration of the Sea.
7 In general Estonia shares common problems with other countries, this is especially obvious in Baltic sea.
The round goby Neogobius melanostomus occurs in waters of Poland (near Gdansk) and it is suggested that this species has been introduced there with the ballast water of ships. Until now this species has not yet reached to Estonia, but it could happen in future.
One company dealing with fishery in the eastern part of the Gulf of Finland has calculated that they lost 50 000 USD during 3 years due to Cercopagis pengoi as the species clogged the nets. It could also happen in Estonia.
Canadian beaver (Castor canadensis) is found in Finland and this species is outcompeting native beaver (Castor fiber). The same could happen if Canadian beaver would reach to Estonia.
Very big problems could be caused by Pacifastacus leniusculus. This species distributes crayfish plague, very dangerous deasease that is lethal for our native species noble crayfish (Astacus astacus). At the moment Pacifastacus leniusculus has not yet reached to Estonia, the nearest place where is occurs is the northern part of Latvia (so – very close already!). Sweden has already big problems with this speceis as it dispalaces native crayfish. The problem is that according to the agreement of free trade it is allowed to introduce this species, but it would be necessary to have some provisions restricting the import of living specimen.
Another problematic species is spinecheek crayfish (Orconectes viridis) that occurs already in Lithuania. This species is aggressive and spreads quickly, it could displace our noble crayfish if it would reach to Estonia.