INVASIVE PLANT SPECIES

• THREATS TO NATIVE ECOSYSTEMS
• LIST OF MOST DANGEROUS INVASIVE PLANT SPECIES
• HOGWEED Heracleum sosnowskyi AND ITS DISTRIBUTION IN LATVIA
• DISTRIBUTION OF Sambucus nigra
• ACTIVITIES
• RESEARCH
• LATVIAN ALIEN SPECIES DATABASE
• DOCUMENTS 

Here: Invasive Animal Species in marine ecosystem 

Flora of Latvia or the present plant species composition has developed during the last 10 000 years. Since the first foreign species were introduced several centuries have passed. Separate foreign plant species have been able to overcome the local competition and have become a part of natural ecosystems or naturalised without suppressing the local species. These species are called arheophytes. For example, in the 16th century in Latvia was brought in a medical plant - Acorus calamus that was planted in the ponds of manors. Nowadays Acorus calamus is widespread both near ponds, lakes and rivers. The plant has found its ecological niche and completely stabilised in natural ecosystems.

Several centuries ago with human help in Latvia have appeared also other species, like Viola arvensis, Solanum nigrum, Papaver rhoeas and Urtica urens. Time of arrival of many plant species in Latvia can be determined only approximately. More precise information about several cultural plants and weeds that follow them is obtained from archaeological excavations. Both species that appeared in a natural way and arheophytes are assigned to natural or aborigine (autohtone) flora.

Species that appeared in Latvia with human help and that are called neophytes are considered as foreign (allohtone) flora. To this group belong species, like Populus alba, Solidago canadensis and Artemisia absinthium. With every year increase the density of foreign species in Latvian plant species composition. Studies of specialists of Institute of Biology, Laboratory of Botany show that already 33 % from Pteridophyta and Spermatophyta flora are foreign species (Gavrilova, sulcs 1999). To these species belong escapers from gardens as well as invasive or adventive species and foreign tree species that are grown in forest cultures. Most of foreign species can not compete with local species, therefore in natural ecosystems occur in relatively small areas or their life span is short.

THREATS TO NATIVE ECOSYSTEMS

Among these species are also such that in Latvian environment feel well - grow fast, reproduce and distribute. As a result the newly arrived plants compete the local species out of their habitats often becoming dominating species in the ecosystem. Foreign aggressive species nowadays are called invasive species. Creating an important biological pollution they have become a serious threat to natural ecosystems and species maintenance. There are species that are dangerous even to people, like Heracleum sosnowskii, more here: HOGWEED AND ITS DISTRIBUTION IN LATVIA

There are more than 130 species of garden escapers, one of them is Sambucus nigra, more here.

Especially polluted are human settlements and surrounding areas. The most actual regions are Cesu and Gulbene Districts, coast of the Baltic Sea, surrounding of Riga, Ogre, Liepaja, Ventspils, Rezekne and Jurmala. One of the areas that is most endangered by invasive species is the seacoast because here is relatively low local species competition. In many places plant cover has established only partly or does not exist. In such a situation it is easy for foreign species to occupy new areas, especially if they spread in a vegetative way. One of the most aggressive plant species near the coast is Rosa rugosa. Areas covered by this species increase rapidly destroying localities of rare plant species and dune habitats.

[Top of page]

List of most dangerous invasive plant species

ACTIVITIES

It is planned to establish in Latvia the data basis of invasive plant species and their localities as well as in the frame of the frame of Biological Diversity Monitoring Programme carry out species monitoring. For invasive species firstly analysis of their distribution is necessary. Constantly must be observed the area and vitality of coenopopulations. Indicators could be the number of invasive species and its change, area of the influenced ecosystem, species of intact area and their status.

In the struggle with invasive species local self-governments play an important role that in case of necessity could even issue correspondent regulations to limit these foreign species. Every landowner or administrator also must take responsibility when evaluating where and what to plant, how to grow and control the distribution of the planted species. In the work of determining localities of invasive plant species and limiting their distribution also schools can take part, developing an observation system of foreign aggressive plant species in their surrounding as well taking part to limit their distribution area.

[Top of page]

RESEARCH

• Latvia University of Agriculture
  Researches on Hogweed Heracleum sosnowskyi
• University of Latvia, Faculty of Biology, Department of Botany and Ecology
  Researches on Invasive Plant Species
• University of Latvia, Faculty of Geography and Earth Sciences
  Several researches on Invasive Plant Species

DOCUMENTS

Actual is the problem of invasive plants not only in Latvia but also in the whole world. About it testify:

• The Rio de Janeiro Convention on Biological Diversity (1992)) (Law of Latvia Republic 08.09.1995.). In the 8th article of which it is said that "Every contacting party according to its possibilities and needs: h) will prevent introduction of such foreign species that endanger ecosystems, habitats or species, control or eliminate them.
• Law on Protection of Species and Habitats, (Law of Latvia Republic 16.03.2000).
  Chapter IV. Introduction and re-introduction of population of species.
• On Issuance of Permits for Taking from Wild Non-game Species, Introduction of Wild Species that are Alien to Latvia (Introduction) as well as for Restoration of Previously Extinct Population of Species (Re-introduction). (No. 34/23.01.2001).
• The National Programme of Biodiversity (accepted in the meeting of Cabinet of Minister, Republic of Latvia in May 16, 2000):
• 1. chapter "Baltic Sea and the Gulf of Riga".
  1.6. Prevent expansion of introduced species.
  1.6.1. Ensure a ban on introduction of alien species into natural waters, and restrictions on their growing in fish ponds.
  1.6.2. Control the use of ballast waters.
  1.6.3. Support the study of distribution and population dynamics of introduced species in waters, and their effect of local populations.
• 2. chapter "Beach and dunes".
  2.1.8. Encourage use of local species for dune stabilisation, and prohibit planting of alien species on dunes.
  2.1.9. Limit the growth of expansive plants (for example Rosa rugosa, Hippophae rhamnoides, Eleagnus sp.) growth on dunes.
• 4. chapter "Forests".
  4.4.3. Monitor distribution of alien species in forests and combat expansive species.
  
• 10. chapter "Urban ecosystems".
  10.1. Identify the trends in expansion of distribution of species in human environments, with the appropriate monitoring.
  10.1.1. Control the expansion of aggressive weeds.
• 13. chapter "Forestry".
  13.9. Control the distribution of foreign tree species in forests.
  13.9.1. Utilise specific tending methods in forests with high densities of foreign tree species in plant communities.
• 14. chapter "Agriculture".
  14.8. Contain the distribution of introduced species.
  14.8.2. Promote study of distribution of introduced species and their entry to natural communities.
  14.8.3. Control the distribution of aggressive species, especially by their removal from natural communities.
  14.8.4. Develop and implement regulations on introduction of new crops, and stipulate grower responsibility for damages ensued to local species and communities.
• 15. chapter "Fishery".
  15.3. Prevent entry of foreign fish species or other organisms into the natural environment.
  15.3.1. Control and combat the already widespread aggressive species.
  15.3.2. Assess the safety of the utilised technologies for fish growing in existing aquacultures, and the impact of possible release of the grown foreign species in natural ecosystems.
• 16. chapter "Game animal management".
  16.5. Prevent the impact of introduced species on natural populations.
  16.5.1. Promote hunting of introduced predator species.
  16.5.2. Monitor the population dynamics of introduced predator species.
  16.5.3. Develop legislation on introduction of foreign species, and ensure compliance.
• 21. chapter "Urban environment and city management".
  21.5. Control spread of foreign species in cities.
• Recommendations of the 2nd World Conservation Congress, October, 2000) "2.67. Invasive alien species".
• The Global Invasive Species Programme (2001.08.06.).

[Top of page]

Copyright © Latvian Environment Agency
Information prepared by Daina Dzintare
Photos Ilze Vilks
Webmaster Armands sverns