Effects of habitat management on newly found populations of the endangered weed, Mummenhoffia alliacea (Brassicaceae)

Garlic pennycress (Mummenhoffia alliacea) is a rare weed of the Brassicaceae family, protected in Hungary. In 2021, three new sites of the species were discovered. In addition to these previously unknown occurrences, a detailed study of a roadside occurrence known for a longer time but not yet published was carried out. Main aim of our study was to find out how habitat management practices, such as mowing and winter-deicing effects seed mass and germination. Seeds collected earlier had significantly lower mass than those from later collections, suggesting that late-spring mowing would be optimal for the reproduction of M. alliacea. The type of mowing (chopping the stem into small pieces or cutting the stem at one point at few centimetres above ground) had no significant effect on seed germination but did have a significant effect on the seed mass. Seed mass deriving from whole individuals was significantly higher than seed mass of chopped individuals, suggesting, that traditional mowing methods are better than the use of modern lawnmowers for the survival of the species. The highest NaCl (used for winter-deicing) concentration where germination was observed was 0.75 m/m% (mass percentage), which is comparable with strongly saline soils in nature. The newly discovered sites were all disturbed, one of which was located on roadsides (paved and dirt roads) and two on embankments, suggesting that anthropogenic habitats could be optimal for the species, but the long-term survival depends on the management of these habitats.