Biotopes must be densely green and characterized by wild plants – that is the common notion. What you discover in Aschheim near the reservoir and east of the Birkenhof hidden between fields does not fit this picture at all at first glance. The approximately 1.1 hectare area, bordered by dry reeds and bare, reddish shimmering willow scrub, consists mainly of gravel. You won’t find lush greenery here, the area looks barren and anything but inviting for animals. But appearances are deceptive, says Norbert Steinmeier, chairman of the local branch of the Federal Nature Conservation Association (BN) for Aschheim, Feldkirchen and Kirchheim. The biotope – a compensation area of the federal Autobahn-GmbH – could become a valuable habitat for certain species precisely because of its nutrient-poor soil.
Birds like the little ringed plover usually breed on gravel banks along rivers. They should find a home in the area.
(Photo: Erhard Nerger/imago images/imagebroker)
In nature, similar areas are usually created by floods on rivers, as Steinmeier explains. Because flowing water transports gravel, which is then deposited into banks. According to the nature conservationist, certain animals have specialized in the difficult conditions prevailing there, including birds such as wagtails or little ringed plovers, which can rest there while passing through and look for food.
Insects such as the blue-winged grasshopper are also dependent on gravel surfaces.
(Photo: F. Perseke/dpa)
Various grasshoppers, for example the blue-winged grasshopper, also find the right environment here. Gravel areas that are poor in nutrients may appear hostile to life at first, but according to Steinmeier: “These species need fewer nutrients and are well adapted to this habitat.” On nutrient-rich areas, on the other hand, they would not be able to hold their own against conventional species. “So we need both.”
“The goal for this area is actually little to no vegetation.”
Currently, however, the rampant willows are preventing the biotope in Aschheim from optimally fulfilling its function. “The goal for this area is actually little to no vegetation,” says Steinmeier. “Normally you try to preserve as much nature as possible, but in this case you have to remove the pastures.”
The members of the BN have already established that it is not that easy, as Steinmeier explains. Attempts have already been made to remove the vegetation with biotope care teams in coordination with the lower nature conservation authority and the motorway directorate. However, it quickly became apparent that little can be achieved by hand. Steinmeier demonstrates this with a tiny undergrowth, not even knee-high: Even if he pulls hard on it, it stays in the ground, it’s already too deeply rooted.
In order to remove the willows, the use of machines is necessary, and the southern Bavarian branch of the Autobahn-GmbH, the former southern Bavarian motorway directorate, is responsible for this. The fact that this has not yet been implemented is explained by their deputy, Martina Hermes, with the enormous number of compensation areas that have to be maintained in the management area. There are more than 1,400 hectares of such areas throughout southern Bavaria. According to Hermes, keeping them all in perfect condition at the same time is almost impossible.
However, a solution is now in sight for the Aschheim biotope. According to Hermes, the company commissioned to remove the willows will begin shortly. The work must be completed before the end of February, because then the nesting season begins. The biotope should soon offer an optimal habitat again for the animals that are used to gravel surfaces.