Pohansko – yellow rattle helps at Soutok PLA

On the former sandy dune behind the pond near Pohansko Castle, there is an inconspicuous grassy area heavily overgrown with an invasive grass, Calamagrostis epigejos. In cooperation with the Soutok Protected Landscape Area, we have sown a root-parasitic plant here - the yellow rattle (Rhinanthus alectorolophus), which is highly effective at suppressing the dominant grass, thereby freeing up more space for native herb species that are being suppressed by the dominant. And because fallow deer, roe deer, and other animals kept in the Soutok game reserve are very effective at suppressing Rhinanthus, we had to erect a temporary fence specifically for it.

The yellow rattle – a small but clever ecosystem engineer

The yellow rattle (Rhinanthus alectorolophus) is a root hemi-parasite. At first glance, it looks like an ordinary plant – it grows out of the ground, has green leaves and carries out photosynthesis. Beneath the ground, however, it uses specialised organs (haustoria) to attach itself to the roots of surrounding plants – its hosts – from which it draws water and nutrients. In doing so, it simultaneously weakens the hosts, causing them to grow more slowly, remain shorter and be less competitive. This frees up space and light in the vegetation for smaller herbs, which would otherwise easily lose out to the competition from grasses.
The yellow rattle parasitises grasses well, particularly species with rhizomes, such as the wood small-reed (Calamagrostis epigejos). Conversely, many flowering herbs tend to be poor hosts for the yellow rattle (e.g. common daisy – Leucanthemum vulgare), so it affects them less or not at all. Furthermore, the yellow rattle has yellow flowers and provides nectar for pollinators. It is a native annual plant, and to ensure it persists in an area, mowing must be timed so that it has time to set seed each year.

What is our goal here?

On a pilot plot within a fenced area, we are testing how sowing yellow rattle can help transform a patch of land, degraded by reed encroachment and intensive grazing, into a more species-rich habitat with greater native plant diversity. Various insect species will subsequently benefit from reduced grass dominance and greater density and diversity of flowering herbs. The yellow rattle sown in the fenced plot originates from a South Moravian population and is well adapted to the dry and warm climate of Pannonia.

Who do we work with?

This area was created through collaboration between the PannFlora project team and the management of the Soutok Protected Landscape Area.