Plant Ecology and Evolution 149(1): 31-38, doi: 10.5091/plecevo.2016.1114
Response of two hemiparasitic Orobanchaceae species to mowing dates: implications for grassland conservation and restoration practice
expand article infoPetr Blažek, Jan Lepš, Karel Fajmon, Jakub Těšitel
Open Access
Background and aimsRhinanthus major (= R. angustifolius ) and Melampyrum nemorosum are very sensitive to mowing date. As they are annuals without a long-term persistent seed bank and with a poor long-distance dispersal ability, seed loss caused by an unsuitable mowing date could lead to rapid population decline. Since their populations have disappeared from productive grasslands, they have become a focus of conservational management. Rhinanthus is also used in restoration projects as a treatment for reducing biomass, where its permanent populations are desired. We aimed to determine the earliest suitable mowing date for these species in White Carpathians Protected Landscape Area to support its administration to plan the management.
Methods – We conducted a mowing experiment with plots mown on 7 and 18 June and 5 July 2012. The number of parasites was counted in central plots before mowing and in the following growing season. The phenology of hemiparasites and co-occurring species was recorded to better understand the effects of mowing date.
Key resultsMelampyrum showed a significant population decrease after mowing on 7 and 18 June, while the 5 July mowing did not inflict any significant change. The effect on Rhinanthus was not significant, as it was probably obscured by seed dispersal from the close surroundings.
Conclusions – Mowing in July is suitable for both species, while June mowing leads to population declines. Mosaic mowing (which includes early mowing in some parts of a site), could therefore gradually eradicate Melampyrum. Rhinanthus metapopulation could compensate for the seed loss by seed dispersal from neighbouring parts, but careful monitoring is necessary. When using Rhinanthus in restoration experiments, postponed mowing is essential to keep its population permanent. Our conclusions are widely applicable, but the particular mowing date must be determined separately for each region, species and ecotype.
agri-environmental schemes, Yellow rattle, Wood cow-wheat, hemiparasite, differential mowing, delayed mowing, grassland restoration, White Carpathians, conservation, endangered species