Pilot Project Neophytes Reppischtal

The pilot project "Together against neophytes" in the Reppischtal, which was launched in 2017 to intensively control invasive alien plants, will end in 2020. All green areas from Birmensdorf to Hausen am Albis have been thoroughly searched for neophytes and professionally combated over the last four years. The nature network took on the key role in the project concept of providing local resources for intensified control measures where there was a lack of these.

The successes are evident. In many areas that were heavily infested with invasive non-native plants at the beginning of the project phase, only a few individual plants can be found, which can be quickly weeded with little effort. A follow-up phase is gradually emerging in which complex and time-consuming group operations can be dispensed with.

Nevertheless, certain species are very persistent. These include, for example, fleabane (Erigeron annuus) in which the plants were able to store thousands of seeds in the soil in the years before the pilot project. Studies carried out as part of the project indicate that this seed supply is considerable and can therefore significantly prolong weeding work. The results also suggest, however, that the seed dispersal potential in the surrounding area is much lower than previously assumed. The same problems are evidently also evident in the lesser-known goat's rue (Galega officinalis). In such areas, there is no other option than to weed the emerging plants every year, as replacing the topsoil with uncontaminated soil is too expensive and usually not feasible.

With the completion of the pilot project, the responsibility for containing invasive alien plants will return to the municipalities and specialist departments. Combating neophytes is not simply completed with the completion of the pilot project, but now the most difficult task begins: removing fragmented individual populations in good time, ideally before they bloom, in order to achieve eradication.

The Nature Network hopes that the population reductions achieved will continue to be weeded in the years to come until they are eradicated. The Nature Network will certainly continue to combat one or two of the neuralgic large populations in the Reppisch Valley in the future.