More Insect Meadows [01.07.21]
The campus of the University of Hohenheim is considered the most species-rich in the state. This is mainly due to the extensive grounds of the Hohenheim Gardens with a low mowing cycle. A contrast to this, however, used to be the "tidy" lawns around the buildings. This is not exactly insect-friendly - and therefore does not fit in with the message that researchers at the University of Hohenheim want to convey to society in view of the dramatic loss of species. After several years of dialog with the State Office for Property and Construction, the "Ecological Campus" working group has now been able to make important progress this year. The Online Courier uses maps to show exactly what is happening and where biodiversity hotspots can already be found.
The background is serious. "The species extinction we have observed in recent years is dramatic. Affected are beetles, wild bees, wasps, butterflies, spiders and wild herbs alike: They all make an invaluable contribution to the ecosystem, and thus ultimately also secure our livelihood," stated Prof. Dr. Martin Hasselmann from the Livestock Population Genomics department.
In the Hohenheim Gardens, species conservation has been a top priority for many years. In the landscape garden and vegetation history areas, meadows are only mowed twice a year and the cuttings are given to a farmer as animal feed. But especially in the green areas in the center of the campus, where most of the visitor traffic is, things often looked quite different recently.
University aims to be a pioneer
It is precisely on these areas that something is to change. A working group of committed professors, employees of the Hohenheim Gardens, the Agricultural Experiment Station, the University Administration and students from the "Bunte Wiese Stuttgart" initiative has been working on this for a good two years.
"You could say: A few square meters more or less meadow on campus - that doesn't make much difference. But we are primarily concerned with the communicative effect," explains Prof. Dr. Hasselmann. "If we as a university want to have an impact on society, we should set a good example - and not just in peripheral areas of the campus, but exactly where it catches the eye of visitors and university members the most."
Status quo: What has the situation been so far?
Less mowing, native plants instead of colorful exotics, letting "untidy" corners with fallen leaves and wood persist through the winter: That should actually be possible to implement on the Hohenheim campus without any major problems - one would think.
In fact, however, things are not quite so simple. The University is not directly responsible for the majority of the areas around the buildings, but rather the University Building Office, an agency of the State Office for Property and Property Management, which is assigned to the Ministry of Finance.
The building authority took note of the university's request two years ago and promised to remain in dialog and make changes step by step. However, the practical implementation of measures was initially slow, for example with meadow strips along Kirschenallee (eastern campus access road) or with flowering strips at the Palace.
Background: The large-scale changeover in green maintenance also brings with it new challenges. For example, if a green area is not mowed for a longer period of time, special equipment is required. The cuttings cannot be left on the areas as before, but must be transported away and, if necessary, processed into hay beforehand. In addition, the University Building Office has repeatedly been confronted with complaints about supposedly "unkempt" green areas.
In recent years, biodiversity measures have therefore been implemented primarily in areas where the University is directly responsible. The fact that this approach is paying off can already be observed in many places. Some of the hotspots with particularly high biodiversity that have been created in this way are being monitored by biologists as part of project work, and the changes they have undergone are being recorded.
A map with a description of the existing biodiversity hotspots can be found at the end of the article.
What is currently happening?
In November, State Secretary Gisela Splett (Green Party) from the Ministry of Finance personally took a look at the situation and pledged her support for further ecological measures. In addition, in spring the student initiative "Bunte Wiese Stuttgart" succeeded in winning over Hohenheim's most famous alumnus, Minister President Winfried Kretschmann, as a patron.
This year, however, the persistence of the players has also borne very tangible fruit: the University Building Office has agreed to designate additional areas in the center of the campus as a meadow that will only be mowed twice a year with immediate effect.
These include areas to the north and south of Hohenheim Palace, as well as around the Verfügungsgebäude, where from now on mowing will only take place twice a year. For this purpose, a new service provider has been commissioned to take care of the greenery, which meets all special requirements, including haymaking. The University agreed to use part of the cuttings in the research biogas plant. For the remainder, the University Building Office was able to secure a local farmer as a buyer.
Mowed strips along the paths should ensure greater acceptance among visitors, making it clear that meadows here are deliberately mowed later and have not been forgotten. In addition, new signs will provide information about the background in the future - and encourage people to follow suit.
As a next step, a new nature trail along Garbenstraße is planned for next spring. Five to eight 3 x 3 m model areas are to be laid out, with the institutes of the professors involved in the working group each taking over the maintenance sponsorship for one. These signposted model areas are to show how habitats develop under different conditions if they are effectively left to their own devices.
Background: what about the remaining areas?
As for the remaining lawns around the buildings, the working group plans to continue talking with the University Building Office. "Perhaps, once the measures taken so far have settled in, we will be able to look at other areas step by step," Hasselmann said hopefully.
Even the areas that are directly administered by the University cannot all be converted into insect meadows. The Exotic Garden, for example, is a protected monument, along with the associated short-mowed lawn. A compromise for more biodiversity is created here by specially designated flower strips.
A large part of the green areas near the campus is also needed as forage meadows for the Meiereihof research station. These grassland areas are managed without chemical pesticides and mowed 3 times a year.
"For the feed supply of the dairy cows, two cuts would be sufficient for us. Inevitably, however, we have to make a third cut to take cover from the field mice. These can then be better hunted by birds of prey and can thus cause less damage. In addition, the rotting grass would contaminate the fresh grass with rotting and mold fungi in the coming year, thus affecting the health of the animals," explained Herbert Stelz from the Agricultural Experiment Station.
With the areas needed for agricultural sciences experiments, the University of Hohenheim also makes a variety of contributions to more biodiversity and ecology.
On the experimental areas east of the Palace, for example, the "NOcsPS" project is testing a new agricultural system between conventional and organic, in which chemical pesticides are dispensed with but mineral fertilizers are used.
Another example is an experiment currently being conducted on the Heidfeld Farm west of campus (not pictured). There, the departments of Landscape Ecology and Vegetation Science and Ecology of Tropical Agricultural Systems are investigating how different conservation measures can be integrated into intensively used agricultural landscapes. After all, large-scale monocultures are considered one of the main causes of species extinction.
"We are interested in the effect of measures that can be implemented in a narrow strip along the field and aim to provide a diverse range of resources for different species groups. These include a perennial flower mix, tilling at two different times to create open soil, adding sand as a substrate for soil-nesting wild bees, for example, and targeted planting of rare field wild herbs. To monitor the effects on biodiversity, we regularly record which plants and insects settle in our experimental plots during the growing season and compare that with plots managed in the conventional way," explained Dr. Christine Sabine Sheppard of the Landscape Ecology and Vegetation Science department.
Text: Leonhardmair / Translation: Neudorfer
