• February 13, 2026

Combating invasive alien species

Invasive alien species are a major problem for our biodiversity. Because these species should not actually be present here without human intervention, they have no natural enemies and proliferate enormously. As a result, many other species are outcompeted and biodiversity declines dramatically. That is why we are combating these invasive species as much as possible.

 

This is also an important part of nature restoration within LIFE Multi Peat. More specifically, we focus on combating species such as Himalayan balsam (Impatiens glandulifera), American red oak (Quercus runbra)  and Black cherry (Prunus serotina).

 

To combat American red oak, large trees need to be felled, but the most work is done afterwards to remove the massive growth of young American red oak trees. In the Valley of the Grote Beek, several hectares of this very dense American red oak growth were recently felled under the high-voltage power line. We are now following this up with mowing management and allowing it to develop back into broom scrub, a type of high-quality nature with a high level of biodiversity.

 

Black cherry is sprouting up everywhere. We even find this species in the wettest part of the marsh forest. This is also being combated. Everything that can be pulled out by hand is pulled out, and larger trees are ringed. To do this, the bark and the layer of “cambium” are removed. This causes the tree to die gradually and also prevents a lot of new shoots from growing from the same tree.

But Himalayan balsam is also a major problem in the valley. It flings its seeds up to 10 metres away when touched. Typically, these seeds then fall into the stream and are spread over long distances. Within LIFE Multi Peat, we are working on an integrated approach to combating this species, starting at the source and working downstream. To this end, all Himalayan balsams are pulled out or mowed (if they cover a large area) before they go to seed. This prevents further spread. We are now doing this for the second year in a row, but the coming years are particularly crucial. If we can continue this for four years, the species should be largely eradicated. 

 

So if you see Himalayan balsam anywhere, don't scatter the seeds, but pull up the plant and place it somewhere with its roots facing upwards, or in piles on a dry patch in the sun.