Duna-Ipoly National Park Directorate (DINPI) has conducted significant habitat restoration works in the Szentmártonkáta shooting range.In the project, DINPI has cleaned about 23 hectares of special significance habitats of Pannon sand grass from aggressive invasive plant species, primarily from pseudoacacia and celtis occidentalis, along with herbaceous milkweed. The protected plant- and animal species could finally breathe with relief: the direct danger of forest- and weed growth is eliminated for now. However, the area is surrounded from more than one directions by forest patches consisting the above mentioned alien tree species, representing a continuous risk of re-invasion of the grasses cleaned up earlier.
In order to prevent this, DINPI is conducting a so called tree species replacement forest restructuring on approx. 12 hectares. We started our work by the complete removal of the tree population consisting almost exclusively non-native species (primarily acacia, celtis occidentalis and prunus serotina), including the roots. This was essential, because the invasive and prevailing species are very capable to grow from trunks and roots. A complete turf preparation represents a dramatic intervention in the biodiversity of an area, therefore, in protected areas, it’s only applied when its really necessary. The dismay sight during the works may be sad to outsiders, but it is part of the process. Unfortunately, this is the price we have to pay to create a healthier forest adapting to local vegetation conditions and providing better ecological circumstances to the flora and fauna.
In the following, I will list the most important advantages worth of such “destruction”. One of these is a change of the nutrient balance of the forest turf for the better. It is a widely known fact that acacia roots accommodate bacteria collecting nitrogen, increasing the nitrogen content of the upper layer of the soil used by herbaceous plants. For the most indigenous species, this makes the area unusable. Only a few nitrophilous weed species will survive, radically reducing the biodiversity of native species. We hope that the replacement of this closed acacia population and the emergence of forest patches with several glades will allow for the gradual return of protected plants such as the achillea ochroleuca, onosma arenaria, dianthus serotinus or alkanna tinctoria.
Another increasingly significant factor is that indigenous tree species (acer campestre, wild pear, wild apples, English oak, domestic aspen) combined with a bordering area of also indigenous bush species (e.g. blackthorns, eglantines and hawthorns) offer more versatile and balanced quality of nectar and farina for visiting insects, as opposed to a largely homogenous acacia. This latter is clearly a paradise for pollenizing bees, but only for about three to four weeks of the year. Before and after this period, it doesn’t offer anything. The primary beneficiaries of this phenomenon are apiarists, as they are able to collect large quantities of nectar in a short time and in a small area. However, a diverse forest with the surrounding grass areas rich in flowers is continuously able to provide food for these important insects from Spring to Fall, even if with less intensity.