There is displacement competition in the Dachau flora: so-called neophytes spread at the expense of native species. How environmentalists in the county are responding to the problem.
A battle rages between rodents in Europe: the gray squirrel from North America is in the process of ousting the native squirrel. In England, for example, there are “only remnants” of the native species, according to the Nature Conservation Union, and Germany could also be targeted by the wandering gray squirrels. A similar displacement competition in the Dachau flora has long been a reality. In the main role: neophytes, i.e. plant species that are not native to this country, but have nonetheless established themselves permanently. Some neophytes threaten the native flora and fauna, others have long since become dear to our hearts, for example the potato.
The term neophyte comes from the Greek and means “new plant”. According to the Federal Agency for Nature Conservation, this is understood to be alien plant species that were not native to Europe before America was discovered. They came to Europe from North America and East Asia in various ways. Once you arrive, “you will never get rid of the species completely”, says Sybille Hein from Nature and Landscape Protection Dachau. This development has been causing the district great difficulties for many years.
The main problem with neophytes: They can grow up to two meters high and simply take the space for native plants to grow. Basically, the local spread of neophytes affects both the insect and the plant world. Certain species can even be dangerous to humans. Peter Heller from the Bund Naturschutz(BN) in Dachau complains about the settlement of non-native plants in the region. He is particularly concerned about the Canadian goldenrod, the Indian balsam and the giant hogweed. “The neophytes gradually settle here and displace our plants,” says Heller. The Canadian goldenrod and Indian balsam are particularly common on riverside regions. There is also too much of the Indian balsam on the Amper. There are other “hotspots” in the district, for example, in Dachau-Ost in the direction of the herb garden or in the Alte Würm, says Sybille Hein. Forest edges are also affected. According to the BN, these areas are particularly important for maintaining biodiversity. Heller emphasizes that one must keep non-native plants away from forest edges in order to “reduce the impoverishment of the landscape” to prevent. Contact with the giant hogweed can also be dangerous for humans and lead to serious health problems, warns Hein. The sap contains substances that are toxic to humans and could cause burns in sunlight. Hein therefore recommends wearing protective suits every time you work with the hogweed.
However, there are also good sides to the “new plants “. Certain neophytes can be useful: Wolfgang Niedermeier from the Dachau District Beekeeping Association emphasizes that the Indian balsam is an important source of food for bees. However, he too is concerned about the rapid spread. Because “as soon as the bees find something, they naturally try to enter it and nature does not foresee that to that extent”. The work that a bee would need in spring is then already done in winter. Niedermeier emphasizes how important “a clever frost” would be in the middle of October, so that “the catch crops and balsam overturn”. If this does not happen, the bees continue to register that the natural cycle becomes unbalanced.
The introduction of the neophytes was not entirely unintentional. According to the Federal Agency for Nature Conservation, half of the plants established here were deliberately introduced as useful plants. For example the potato, the tomato or the corn. The only problematic are those neophytes that reproduce uncontrollably and displace native flora. “It is difficult to do something about it. You would need an army of people and government funds,” said Heller. The fight is just hard to win. However, targeted measures can help to protect native species.
The BN Dachau has been organizing so-called “neophyte campaigns” for years. From mid-May to mid-August, volunteers clear the area of the Amperau from Indian balsam and Canadian goldenrod once a week. These actions promise success and, according to Heller, would help to contain the spread. “If nothing is done, native plants will disappear completely.”