Four invasive species are a problem in the reserve.

Wood small-reed (Calamagrostis epigejos) is present in the center of the site and threatens to spread into herbaceous areas.
It compromises sustainability of stations, including man orchid and bee orchid populations.
Two distinct zones can be distinguished.
The first, where the wood small-reed has a very high rate of recovery, is not hosting any heritage value.
It is mowed early and disposed of.
Grazing is not possible at the moment.
The second, on the contrary, not densely colonized by this plant is much more of a fragile situation due to the presence of orchids and the sickle-bearing bush cricket or long-horned groundhopper.
Differentiated management is applied depending on the issues.
At orchid stations, slight thinning is done early by hand pruning.
The less dense areas where the grass is sparse (conducive to the long-horned groundhopper (Tetrix tenuicornis)) are pulled.
In the newly opened areas, a systematic and annual pulling avoids expansion.
Finally, dense areas, well exposed, are left in that state.

Many extensive areas of Japanese knotweed (Fallopia japonica) are on the site.
Heritage stations of common butterbur and hart's-tongue fern, colonized by invasive species, are managed by manual removal and disposal for incineration.

The bramble (Rubus sp.)
lie around the ruins and along the south-east of the site near the houses.
Due to an interest in preserving wildlife (e.g. refuge for mammals, insects, nesting wrens), they are not eradicated but contained.

Canada golden-rod (Solidago canadensis) appeared in 2003 as a result of plant deposits.
The threat proved to be serious the following year.
Some stations show a significant concentration of the species, while isolated plants grow everywhere on the site.
This plant is easily pulled by hand before flowering to prevent seed dispersal, and the shoots are burned.

Finally, panicled aster (Symphyotrichum lanceolatum) is also present among the invasive plants.
In their native countries, American asters are found in wet places.
In France, these plants colonize relatively dry ruderal areas (brownfields, road shoulder ...) or wetlands.
In this second case, asters show strong invasive behavior.
In the reserve, where the majority of areas are dry, this plant does not present special hazards and removal is managed easily.
Four invasive species are a problem in the reserve.
Wood small-reed (Calamagrostis epigejos) is present in the center of the site and threatens to spread into herbaceous areas. It compromises sustainability of stations, including man orchid and bee orchid populations. Two distinct zones can be distinguished. The first, where the wood small-reed has a very high rate of recovery, is not hosting any heritage value. It is mowed early and disposed of. Grazing is not possible at the moment. The second, on the contrary, not densely colonized by this plant is much more of a fragile situation due to the presence of orchids and the sickle-bearing bush cricket or long-horned groundhopper. Differentiated management is applied depending on the issues. At orchid stations, slight thinning is done early by hand pruning. The less dense areas where the grass is sparse (conducive to the long-horned groundhopper (Tetrix tenuicornis)) are pulled. In the newly opened areas, a systematic and annual pulling avoids expansion. Finally, dense areas, well exposed, are left in that state.
Many extensive areas of Japanese knotweed (Fallopia japonica) are on the site. Heritage stations of common butterbur and hart's-tongue fern, colonized by invasive species, are managed by manual removal and disposal for incineration.
The bramble (Rubus sp.) lie around the ruins and along the south-east of the site near the houses. Due to an interest in preserving wildlife (e.g. refuge for mammals, insects, nesting wrens), they are not eradicated but contained.
Canada golden-rod (Solidago canadensis) appeared in 2003 as a result of plant deposits. The threat proved to be serious the following year. Some stations show a significant concentration of the species, while isolated plants grow everywhere on the site. This plant is easily pulled by hand before flowering to prevent seed dispersal, and the shoots are burned.
Finally, panicled aster (Symphyotrichum lanceolatum) is also present among the invasive plants. In their native countries, American asters are found in wet places. In France, these plants colonize relatively dry ruderal areas (brownfields, road shoulder ...) or wetlands. In this second case, asters show strong invasive behavior. In the reserve, where the majority of areas are dry, this plant does not present special hazards and removal is managed easily.
Carrière des Nerviens Regional Nature Reserve