Establishment of hemiparasitic Rhinanthus spp. in grassland restoration: lessons learned from sowing experiments

Abstract

Questions: What are the factors limiting the establishment of hemiparasitic Rhinanthus spp., ecosystem engineers promoting diversity and stability of communities, in restoration of species-rich meadows? How can these constraints be overcome?Location: Czech Republic, Central Europe.Methods: Sowing of Rhinanthus seeds in grasslands of different history, biotic and abiotic properties accompanied by a variety of management practices. Followed by consequent monitoring of establishment and population dynamics and synthesis of relevant literature resources.Conclusion: Mowing or grazing, litter removal, proper timing of sowing, and use of the seeds from local seed sources should considerably increase probability of Rhinanthus successful introduction. However, stochastic events like adverse weather conditions or damage through herbivory make the prediction of introduction success difficult.

Suppressing competitive dominants and community restoration with native parasitic plants using the hemiparasitic Rhinanthus alectorolophus and the dominant grass Calamagrostis epigejos

“…Two experimental treatments were combined in a full factorial design: (i) sowing of R. alectorolophus (500 seeds m −2 ) and (ii) an additional mowing in October (including litter removal and gentle moss layer disturbance by raking, a treatment known to potentially improve Rhinanthus establishment; Mudrák et al . ). This resulted in four treatment combinations within each block: (i) summer mowing only (control; corresponds to recommended conservation management), (ii) summer and autumn mowing (corresponds to conventional restoration management of C. epigejos‐ heavily infested sites), (iii) summer mowing + Rhinanthus , (iv) summer and autumn mowing + Rhinanthus .…”

“…A recent pilot experiment demonstrated the ability of root‐hemiparasitic R. alectorolophus to establish in C. epigejos‐ dominated vegetation (Mudrák et al . ) and form functional haustorial connections to its roots (Fig. , Supporting Information).…”

Victims of agricultural intensification: Mowing date affects Rhinanthus spp. regeneration and fruit ripening

“…The site is mown shortly before the Czech school holidays, which start at the beginning of July. Our experimental plot in Benešov (reported in Mudrák et al, 2014) is also usually mown before the end of June, and the population of Rh. minor, spreading vigorously throughout the locality after artificial introduction, survives more than a decade on.…”

“…Rhinanthus is included in sown seed mixtures as one of the desired indigenous species (Smith et al, 2000), or even as a treatment that should help with lowering biomass thanks to its parasitism (Bullock and Pywell, 2005;Westbury et al, 2006;Westbury and Dunnett, 2007;Mudrák et al, 2014). To keep permanent Rhinanthus populations in such sites, the proper timing of mowing must be applied and our results can be used as a guideline.…”

“…If mowing starts to interfere with Rhinanthus flowering, which can happen when the first cut is shifted to an earlier date, Rhinanthus seed production could be decreased. As an annual with poor dispersal (Bullock et al, 2003) and an only shortterm persistent seed bank (ter Borg, 1985;van Hulst et al, 1987;Mudrák et al, 2014), Rhinanthus is expected to respond rapidly to a decrease in seed production (Smith et al, 2000;Westbury, 2004;Bullock and Pywell, 2005;Bullock et al, 2008). The impact of seed loss caused by early mowing on Rhinanthus population persistence has been documented (Smith et al, 2000;Magda et al, 2004), but neither of these studies described the seasonal dynamics in detail.…”