In the nature of Latvia, alien plants are spreading more and more, which threaten the local ecosystems. Everyone has known about the evil of Sosnovskii latvānis for a long time, the fight against the spread of this plant has been going on at the national level for years. But there are many beautiful plants that we don’t even suspect could be dangerous because they are alien and multiply rapidly, suppressing traditional habitats and food chains. This is also the case of the Canadian zeltslavite, or zeltslotina, with which the fight was also started on the side of Kuldīga last year.
AFTER Ventas valley in autumn after repeated mowing, leaving biomass for restoration of natural grassland. In Kuldiga, last year, the fight against the Canadian golden sloth with the method of mowing and shredding was started.
Beautiful, but ugly
Last year, the municipality of Kuldīga county took the opportunity to receive co-financing from the European Union’s LIFE program and participated in the project competition “Small grant scheme for the management of invasive species” in order to start the fight against the Canadian golden sloth (‘Solidago canadensis’), which has multiplied significantly in the nature reserve “Venta valley”, as also elsewhere in the city and in the countryside.
In this project, on an area of 3 ha on Virkas street (in the territory of the reserve), systematic mowing and shredding is intended to eradicate the magnificent plant, which is alien to our nature, as well as to prevent its further spread. Last year, the area was cleared of bushes, leaving the largest, most valuable trees, and with several mowings, a well-kept meadow without invasive species was created. The cut and chopped biomass is left there as fertilizer for the lawn. This year, the work will continue in the places where the golden sloth has reappeared.
“In the beginning, we mowed twice a month, after the plant was already weakened, we switched to mowing once a month,” says municipal environmental inspector Inta Putniņa. “It cannot be destroyed so easily, because the roots have grown densely for a long time. The land has been depleted for years, other plants have been outcompeted. It is important to prevent the seeds from flowering and ripening. We chopped up the clippings and left them as fertilizer for the natural lawn. Let’s see what flowers will grow there this year. It is the biggest problem that invasive species have been allowed to take root and spread for too long, completely suppressing native plants. It is possible that people do not know or are not aware of their harmfulness.
The goldenrod has multiplied greatly from abandoned gardens, where it continues to grow: after flowering, the seeds are sown, the wind blows them away, and the river water carries them far away. Therefore, the golden yellow flowers can often be seen on roadsides, riverbanks. Now it is no longer seen, but once during flowering, the goldenrod was often used in floristry – it was imported directly as a decorative plant. It was also used in medicine. There are many other non-native plants that are allowed to spread freely: multi-leaved lupine, flower spikes, red elder and others. It already looks beautiful, but we must remember that such plants are dangerous for our nature, because they do not allow anything else to grow.”
Big, poisonous dill
The battle with Sosnovsky’s Latvian (‘Heracleum sosnovskyi’) is older, which is considered the most dangerous and also the most resistant alien, which threatens biological diversity in Latvia, as well as in other Baltic countries and Europe. It was once brought to us for the cultivation of fodder, but it turned out that the latvan has a devastating effect on local cultures, changes the functions of ecosystems, causing both economic losses (the value of agricultural and forest land decreases) and also a danger to human health. Its flower resembles a giant dill flower, and the leaves are like rhubarb, but the plant is very poisonous – even touching it with your hands can cause permanent burns and long-lasting itching. The number of territories covered by latvana grows every year, as tens of thousands of seeds ripen in inflorescences, the further spread of which is facilitated by wind, birds and agrotechnical carelessness.
In Kuldīga county, the most Latvians have settled in Pelču parish. I. Putniņa says that in other places there are small, separate stands in both municipal and private properties, but in some parishes Latvians have not been found at all.
In September 2020, the municipality developed the “Sosnovska Latvian diffusion control measures plan 2021-2025. year”, but even before that, the spread of this plant was fought both in the city territory and in Kabile, Pelču and other parishes. Kuldīdz residents have understood: one is not a fighter, so the measures must be united and targeted. If everything is done correctly and regularly, it is possible to destroy the Latvians in three to four years. Attracts professional and experienced entrepreneurs who have the appropriate technique to successfully monitor it in practice according to the latest research. Work usually starts in May. If necessary, some areas are sprayed again in the summer. This method can also be used after cutting the Latvians. In places where it is not allowed to use spraying with selective herbicides, the control of latvans is carried out in the second half of summer – from July to September – by cutting inflorescences and seed clusters, as well as repeated buds. In large areas, chemical treatment is much cheaper and more effective compared to mechanical treatment, as it completely stops the further vegetation of Latvians. Misting takes place in spring and summer. Last year, by mechanically cutting inflorescences and seed clusters, it was limited in a large area of 2 ha, and 22.9 ha were sprayed. This year, the volume is increased to 5 and 28 ha, respectively.
On a national scale, the Cabinet of Ministers adopted the first program to limit the spread of Latvians in 2006. Over the course of several years, experiments showed that many traditional herbicides have almost no effect on Latvians and that the glyphosate-containing roundup is also not quite effective in one-time treatment. However, it was already a stepping stone for further struggle using other methods: regular pruning, grazing and proper crop rotation in the infested areas and others. In the following years, the Ministry of Environmental Protection and Regional Development focused on the implementation of such regulations, so that all landowners, both private and municipal, take responsibility for the fight against the Latvian weed.
You have to start with the first plant
“In the spring, the Latvians of Sosnovska start their vegetation particularly richly – with the development of large leaves and abundant inflorescences,” says environmental specialist I. Putniņa. “We call on every land owner, on whose territory Latvians have settled, to prevent the formation of their thicket and to start combating it, using one of the control methods – mechanical, chemical, biological or combined. In private properties, Latvian roots or seeds most often end up with black soil of unknown origin. The work will be more successful if you start fighting with the first plants as soon as they appear. In small backyard areas, the cheapest and fastest way is to pierce the root rosette with a spade in the spring, when the plant has emerged from the ground at a height of 10-20 cm. The root is pierced at a depth of 5-10 cm, then the area is covered with a black film for the whole summer and the excavated Latvian roots are thrown on it to dry,” she instructs those in whose land the invasive plant has taken root.
On the other hand, when choosing mowing, it should be taken into account that it should be done regularly at least once a week, thus ensuring the growth of other plants, which shade the strangers and take away their strength. Mow as close to the ground as possible and then destroy the plants without allowing the seeds to ripen. Latvians tend to bloom and ripen seeds already 10 cm above the ground, similarly a cut juicy stem can do this. That’s why, as it happens, you can’t destroy this annoying stranger by mowing.
The specialist also reminds that, when starting to combat the Latvians, even though the dangerous plant is relatively small, caution and work safety must be observed: thick rubber gloves must be worn and the cell juice must not be allowed to get on clothing and skin. On the website of the State Plant Protection Service, you can read more detailed information on how to act so that your health does not suffer.
FOR REFERENCE
- A third of the plant and animal species found in Latvia are foreign.
- About 10% of alien species are dangerous: they spread aggressively and outcompete native plants.
- Invasives can cause changes in natural ecosystems, harm the economy and some also harm health.
- Most of the non-native plants were introduced in the 20th century, such as Sosnovska latvanis as a fodder plant, flower sprig and Canadian goldenrod as ornamental garden plants.
- Invasion is mostly the result of human activities, whether conscious or unconscious. Both plants and animals can also enter accidentally: in the holds of ships, mail, plant pots. Climate change also contributes to this, but the biggest contributor is man.
- It is wrong to believe that foreigners increase the diversity of Latvia’s nature. On the contrary, they outcompete local plants and animals, change the soil and environment, destroy the food base and often become a problem for people.
- Garden owners should be responsible for what is grown. The spread of plants outside the territory should not be allowed.
- Invasive species must be combated in time. Some methods: separate, dig or use pesticides in a controlled manner.
