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Save weeds, but be smart!

Wild plants, commonly referred to as weeds, are the most threatened plant group. "Let’s protect native plants, thus preserving biodiversity, which is crucial for the functioning of the ecosystem, insects, animals and finally, ourselves" – appeals Prof. Arkadiusz Nowak from the PAS Botanical Garden. "However, we should remember that not all weeds deserve protection," he adds.

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For at least a decade, one of the greatest environmental disasters of our time has been observed in Poland. Meadows have been declining as a result of changing agricultural policies and practices (the abandonment of traditional farming practices), the massive use of herbicides, and last but not least urban encroachment on agricultural land. The unwanted plants, which grow in field along with the crops, are usually termed as weed. Among commonly known plants classified as weeds are: field poppy, cornflower, corn-cockle, scarlet pimpernel and field larkspur.

But should we really protect wild plants? After all, weeds compete with crops for space and resources (sunlight, water and nutrients). Moreover, most of them are alien species, imported from many other parts of the world along with the seeds of cereals and other arable crops. "Well, yes" – confirms researcher from the Botanical Garden of the Polish Academy of Sciences. “By protecting weeds, we protect a significant part of the natural diversity of our country. Biodiversity stabilizes ecosystem functioning, ” he adds. The widespread extinction of insects and insectivorous birds, which is currently observed, is the result of a dramatic decline of weed diversity. Native fauna rely on weeds to provide food and habitat.

Fortunately, many initiatives have been taken to keep the grasslands where they are and preserve meadows. An effective preservation effort to quickly save the gene pool of endangered weed species is the annual sowing of these species, e.g. on the outskirts of open-air museums, in botanical gardens, protected areas and organic farms. Another good example of participating in biodiversity conservation is the new way of arranging urban green spaces. Recently, some Polish cities have refrained from mowing the grass in parks and green belts and created flowery, urban meadows instead. To sow an urban meadow, they use ready-made mixtures of wildflowers seeds prepared for different types of soil.

Not every weed, however, deserves protection. Weeds that have recently been introduced into our ecosystem, the so-called kenophytes can threaten our native species, or species present in our country for hundreds of years (archaeophytes). Moreover, the efforts to eradicate such invasive species as East Asian knotweed, American goldenrod or milkweed on a large territory is doomed to failure. What is beautiful, useful or fashionable is not always what is best for the environment and economy. "Be smart when protecting weeds! Take care of rare species, and at the same time limit new, common and invasive species that can displace our native plants and weeds that have formed Polish meadows for centuries " – advises Prof. Nowak.

Source of information: Polish Academy of Sciences