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

1. Dominance of native or alien competitive plants causes competitive exclusion of subordinate species and represents a major mechanism reducing biodiversity following land-use changes. The successful competitive strategies may however be interfered with by parasitic plants, which withdraw resources from other plants’ vasculature. Parasitism may strongly reduce the growth of the dominants, which may facilitate regeneration of other species and consequently trigger restoration of natural communities of high diversity.
2. Here, we aim to provide robust empirical evidence demonstrating this restoration potential of parasitic plants. We present a case study testing suppressive effects of hemiparasitic Rhinanthus alectorolophus on competitive grass Calamagrostis epigejos. In recent decades, C. epigejos has invaded many high-nature-value semi-natural grasslands of Central Europe, which is one of the prominent factors causing their biodiversity decline.
3. We conducted three manipulative field experiments testing the effect of sowing of R. alectorolophus in different vegetation types infested by C. epigejos. Rhinanthus sowing was compared to different mowing treatments recommended as the “best practice” management at respective sites.
4. Rhinanthus alectorolophus established itself in most C. epigejos-dominated plots where sown. Calamagrostis epigejos was virtually exterminated in two years in two of the experiments (dry meadow, industrial area). In the wet-meadow experiment, the suppressive effect was variable as a result of uneven establishment success of Rhinanthus. In this experiment increased mowing intensity had an additional suppressive effect on C. epigejos. Rhinanthus also increased regeneration potential of other species by a temporary reduction of vegetation density. Restoration of target vegetation composition was however dependent on community context.
5. Synthesis and application. We demonstrated that hemiparasitic Rhinanthus alectorolophus is an accessible and efficient tool for targeted biological control of C. epigejos, with a great potential to restore infested grassland vegetation. The strong effect of Rhinanthus is caused by interference with the underground storage and clonal growth strategy of C. epigejos, which are both traits that underlie its competitive ability. The potential of native parasitic plants should be considered in restoration management of sites infested by competitive dominants, either alien or native.07-Feb-2017

1. 本土或外来的优势竞争植物占据主导地位会造成从属物种的竞争排斥（competitive exclusion），这是土地利用变化后生物多样性降低的主要机制之一。然而，这类成功的竞争策略可能会受到寄生植物的干扰——寄生植物会从其他植物的维管组织（vasculature）中获取资源。寄生作用可大幅抑制优势植物的生长，进而促进其他物种的更新，最终推动高生物多样性自然群落的恢复。
2. 本研究旨在为寄生植物的这种恢复潜力提供可靠的实证依据。我们开展了一项案例研究，以检验半寄生植物（hemiparasitic）疗齿草（Rhinanthus alectorolophus）对竞争力较强的拂子茅（Calamagrostis epigejos）的抑制效果。近数十年来，拂子茅已入侵中欧诸多具有高自然价值的半天然草原，这是导致这些草原生物多样性下降的重要因素之一。
3. 我们开展了三组控制性野外实验，检验在被拂子茅侵染的不同植被类型中播种疗齿草的效果。同时将疗齿草播种处理与各站点推荐的“最佳实践”管理措施——不同刈割处理——进行对比。
4. 播种的疗齿草在绝大多数以拂子茅为优势的样地中成功定殖。在其中两组实验（干旱草原、工业用地）中，拂子茅在两年内几乎被完全清除。在湿草原实验中，由于疗齿草定殖成功率不均，其抑制效果存在差异；在此实验中，提高刈割强度可额外增强对拂子茅的抑制作用。此外，疗齿草通过暂时降低植被密度，提升了其他物种的更新潜力。但目标植被群落的恢复效果取决于群落背景。
5. 总结与应用：本研究证实，半寄生疗齿草是一种可便捷获取且高效的针对性生物防控（biological control）工具，可用于抑制拂子茅，在恢复被侵染草原植被方面具有巨大潜力。疗齿草的强效作用源于其对拂子茅地下储藏与克隆生长（clonal growth）策略的干扰，而这两种性状正是拂子茅竞争能力的核心基础。对于受竞争优势物种（无论是外来还是本土）侵染的生境，在恢复管理中应考虑利用本土寄生植物的这一潜力。2017年2月7日