Invasive species are taking over fields and damaging roads. Municipalities are failing to meet their obligations.

• There are over 12,000 alien species in Europe. Of these, 10-15% have reproduced and spread, causing environmental damage, but 119 have been added to the EU's list of invasive species posing the greatest threat.
• Mayors and city presidents are responsible for receiving reports of the presence of IGOs in the environment, they formally verify the reports and notify the environmental protection authorities.
• They are also responsible for implementing countermeasures against widespread IGOs that pose a threat to the EU and Poland. However, the Supreme Audit Office (NIK) report reveals that this system is flawed.

The Intergovernmental Platform on Biodiversity and Ecosystem Services warned in a report published in September 2023 that invasive alien species (IAS) pose a global threat to biodiversity. In 60% of recorded cases, they were the main cause of global plant and animal extinctions, and the sole cause in 16%.

It is estimated that over 12,000 alien species exist in Europe. Of these, 10-15% have reproduced and spread, causing significant environmental, economic, and social damage, which amounts to at least €12 billion annually in the European Union and is steadily increasing.

However, we learn of their presence from time to time, specifically from one high-profile case to another. This includes the case of nutria in Rybnik, which were ultimately captured and transported to sanctuaries. There's also the spectacular capture of Louisiana crayfish from ponds in Poznań in 2023. There's the appearance of Asian ladybug invasions and the American ladybug. Finally, there's the rampant spread of Sosnowsky's hogweed, an invasive plant that can cause burns.

As part of a project related to the Invasive Alien Species (IGO), the General Directorate for Environmental Protection (GDOŚ) conducted an analysis of 118 alien species. GDOŚ selected priority invasive species, meaning those that should be combated first. The list includes some that we have become accustomed to as part of our landscape, such as lupine and black locust. The 2022 list of invasive alien species posing a threat to the European Union includes 119 species, including 31 for Poland. These include Sosnowsky's hogweed, knotweeds (Czech, Japanese, and Sakhalin), and the tree Ailanthus glandulifera.

Witold Szwedkowski , an activist in the field of urban greenery and landscape protection, co-founder and one of the Polish leaders of the Urban Gardening Guerrilla, has been involved in the fight against invasive species for many years. When asked if he believes they can be permanently eliminated, he responds with a medical metaphor.

We cannot eliminate genetic defects, congenital diseases, or even diseases in general from the world, but we should make every possible effort to restore them to full health. Similarly, we must strive to do everything possible to prevent ecosystems from exacerbating the disruptions previously caused by humans. We must act to protect what we have.

- emphasizes the naturalist.

He admits that climate change and a scale of travel unprecedented in human history are accelerating the process of alien species' transfer. That's why he's dissatisfied with the fact that academics are defending them. This includes a recent statement by former Poznań Zoo director Ewa Zgrabczyńska in a video on Dorota Sumińska's channel. Dr. Ewa Zgrabczyńska keeps animals classified as "invasive species" in her sanctuary, emphasizing that this term is a myth .

In her opinion, invasive species do not necessarily have a negative impact on our fauna and flora, and there is no research to confirm this.

Szwedkowski believes that while there's still a chance to control the population of individual species, it should be done. For example, by trapping them, as was done with nutria in Rybnik.

The Supreme Audit Office's May 2025 report shows how municipalities are coping with invasive species. This is their responsibility.

The Alien Species Act, which entered into force on December 18, 2021, and was intended to adapt the national system for combating IGOs to the requirements of the European Parliament regulation, entrusts a significant role to commune heads, mayors, and city presidents . They are responsible, among other things, for receiving reports of IGOs detected in the environment, conducting formal verification of the reports, and notifying the relevant environmental protection authorities. The commune head, mayor, or city president is also responsible for implementing remedial measures against IGOs that pose a threat to the EU and Poland and are widespread.

Meanwhile, most of the 12 municipalities audited by the Supreme Audit Office (NIK) failed to properly define tasks related to invasive species control in their municipal environmental protection programs. Five municipalities did not adopt such a program, and in three, these documents were not in effect throughout the audited period. In six municipalities, however, such programs did not include tasks related to the identification and control of invasive species, despite the presence of such species in each of these municipalities.

NIK believes that, apart from the issues related to the financing of activities related to the fight against IGOs (NIK proposes that these costs should be charged to the land manager), there is a large lack of awareness of the scale of the problem, and the problem is further complicated by the complicated reporting method (the need to find, fill in and submit the appropriate form) which discourages people from reporting IGOs.

This is confirmed by Witold Szwedkowski. The Łódź activist says:

When I receive information about questionable architectural and landscaping solutions, I use the Freedom of Information Act to ask when the alien species inventory was conducted, what method was used, which species were identified, what remedial measures were taken, and what the municipal budget is for this. Not one of the seven municipalities I've contacted so far has been able to answer any of these questions. Office representatives sometimes only mention the wildlife inventory conducted in the first decade of the millennium, or they reply perfunctorily that they don't have the funds for such an effort.

He adds that the problem is systemic. "Even if they wanted to, it's not entirely clear what to do with the seedlings of such invasive plant species . Composting in open composting facilities doesn't eliminate seeds or their ability to germinate, nor does it effectively compost the rhizomes. Some vegetative parts can sometimes continue to propagate invasive plants along with the compost."

He also agrees that the problem is often a lack of awareness among officials and local communities, because "who cares about a growing plant" and "it's better than concrete." This, in turn, prevents municipalities from allocating funds for this purpose in their budgets. Meanwhile, he believes it may soon be too late to act.

Ecosystem degradation is progressing, and the costs we incur are mounting. Invasive plants are beginning to encroach on farmlands, causing flood embankments to crack – take knotweed, for example, which thrives in riverine environments. Restoring land that has been overgrown with goldenrod after being abandoned to agricultural production is already generating exorbitant costs. Structures built in areas where knotweed was prevalent begin to fall apart after a dozen or so years. Let's start to recognize that this is no longer a superficial problem.

Witold Szwedkowski adds that local governments sometimes decide to plant invasive plants. Such plans included the black locust at Warsaw's Defilad Square (the city withdrew after pressure from naturalists), and in Łódź, a Virginia ash is being planted despite knowing it is an alien species.

- Didn't they know it was invasive? - Szwedkowski asks rhetorically.

Our interviewee also provides good examples, such as the Kielce Housing Cooperative's fight against Japanese knotweed. The administration began by informing residents about what Japanese knotweed is, when and why it was introduced to Europe, and the consequences: that it now poses a threat to the natural environment and technical infrastructure (pavements, foundations, utilities).

Another example is the inventory of knotweed during the construction of the Northern Route in Szczecin. In mid-June, road workers took up the challenge, fearing for the project's future – the knotweed could simply destroy the road in the future. The knotweed has covered over 4,500 square meters on the construction site, but it also occurs in adjacent areas, so the measures must encompass not only the project itself but also the surrounding area. Removal of the plant (chemical, mechanical, creating buffer zones, and removing layers of soil) will be possible after obtaining a permit from the Regional Directorate for Environmental Protection, but it is already known that it could significantly complicate the work schedule and increase costs.