Hemiparasitic plants help to maintain the lawns on the Bohunice University Campus

"In places where Rhinanthus grows, other flowering plants dominate beside it, not grasses as everywhere around. Thus they enrich the local lawns and consequently, they make space for other plant species. At the same time, they limit the total productivity of the lawn; hence it does not grow as tall and does not need to be cut as often. Ultimately, the hemiparasites also reduce the costs of maintaining the lawn areas," says the botanist Kateřina Knotková from the Department of Botany and Zoology.

They have been growing in the lawns around the university buildings for several years and have gradually expanded. Initially, Rhinanthus was sown here to suppress the grass Calamagrostis epigejos, then Melampyrum was added, but it connects to a different host spectrum. Today, the area originally covered by grasses is a stand of all colours. At the moment the hemiparasites dominate, but there are also Campanula species and various leguminous plants such as Lotus corniculatus.

However, the hemiparasitic plants are not here just for the pleasure of the eye, they also have their scientific significance. Ongoing research by Jakub Těšitel's team, which has also been supported by the Czech Science Foundation, tests the potential of these species to limit the growth of invasive and expansive plant species, and thus help to restore the original biodiversity which existed at the site before the invasion. In simple terms, the project addresses how hemiparasitic plants can be beneficial in the biocontrol of these persistent plants and thus also be helpful in landscape conservation. The results so far indicate a great potential in this regard. Other currently ongoing research is focused on the interactions of semi-parasitic plants with leguminous plants.

Within the framework of the ENVIROP projects at the Faculty of Science, Masaryk University, possible practical applications in conservation management of degraded sites are explored or cooperation with farmers and other entities is established. Seminars for the professional public on the possibilities and limits of using semi-parasites in urban lawns are also prepared.

At first glance, Rhinanthus alectorolophus and Melampyrum arvense look like any other plant. They grow from the ground, are green, and bloom colourfully. However, in soil they are attached by haustoria to the roots of surrounding plants, drawing water and nutrients from them, thus limiting the growth and reproduction of their hosts. Although it might seem that they are pests which destroy plant communities, in nature it works a little differently.

"Despite they are essentially hurting their hosts, they are beneficial for the whole community and its diversity. This is because they are able to suppress the dominant species, making space for less competitive plants which would otherwise not have a chance in a dense, compact stand. They are therefore like ecosystem engineers, helping to maintain a balance in the community. In addition, both species are very attractive to insects, including bees and bumblebees, providing them with food and shelter," explains the young researcher.

Both plants are annuals and grow in dry (Melampyrum) to moderately moist (Rhinanthus) open habitats such as meadows or steppes. They are native to our country and formerly they were considered harmful weeds in the fields, but thanks to improved crop cleaning technologies, they no longer pose a threat to crops, quite the opposite. Due to intensification and greater homogenisation of the landscape, these species have declined significantly and are most often found in protected areas.

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