Suppression effect of hemiparasites on grasses is a phenomenon, that can be utilized to increase biodiversity of various grassland systems. Host suitability, environmental effects, and hemiparasite abundance most likely influence the impact of parasitism on host height and biomass. However, the role of these factors is unclear in field conditions. We studied host suitability, establishment rates, and effects of a hemiparasitic plant Greater yellow rattle [ Rhinanthus alectorolophus (Scop.)] (RA) on canopy height and biomass of a grass tall fescue (Festuca arundinacea Schreb.) in five trials with manipulated fertilization conducted in golf roughs. Particularly, we examined how grass height and biomass changed with increasing hemiparasite abundance. On average, grasses (nine in total) were better hosts than legumes (four in total). Tall fescue belonged to the group of better hosts. The average establishment rate of Rhinanthus plants ranged from 4.4 to 24.8% regardless of fertilization treatments. In fertilization trials, Rhinanthus did not affect grass height but weakly suppressed grass biomass in non‐fertilized plots. The relationship between grass height/biomass and Rhinanthus abundance was best described by a logarithmic decay model. The suppressive effect tended to saturate (negative density dependence) in plots where the Rhinanthus abundance was very high. However, such high densities were quite rare and low Rhinanthus abundances were usually insufficient to substantially suppress grass growth. Our results indicate that we should aim for at least 50 Rhinanthus plants per 1 m² to achieve desirable effects on biodiversity and that Rhinanthus performance will be better when nutrients are rather limiting.

中文翻译：

---

一个半寄生的Rhantanthus alectorolophus的建立及其对草的密度依赖性抑制作用：以高尔夫球毛坯为例

半寄生虫对草的抑制作用是一种现象，可以用来增加各种草地系统的生物多样性。寄主的适宜性，环境影响和半寄生虫的丰度最有可能影响寄生对寄主身高和生物量的影响。但是，这些因素的作用在野外条件尚不清楚。我们研究了寄主的适宜性，建立率以及半寄生植物更大的黄色拨浪鼓[ Rhantanthus alectorolophus（Scop。）]（RA）对草高羊茅（Festuca arundinacea）冠层高度和生物量的影响。（Schreb。）在高尔夫原石上进行的五次受控施肥试验。特别是，我们研究了半高寄生虫丰度增加时草高和生物量如何变化。平均而言，草（总共九种）比豆类（总共四种）更好。高羊茅属于更好的主人。无论施肥方法如何，Rhinanthus植物的平均定殖率在4.4％至24.8％之间。在施肥试验中，Rhinanthus不会影响草高，但在未施肥的地块中抑制草的生物量微弱。草高/生物量与 花木的关系 对数衰减模型可以最好地描述丰度。在Rhantanthus丰度非常高的地块中，抑制效果趋于饱和（负密度依赖性）。然而，如此高的密度非常罕见，而较低的 杜鹃花 丰度通常不足以充分抑制草的生长。我们的结果表明，我们的目标应该是每1 m ²至少有50 株Rhinanthus 植物 对生物多样性产生理想的影响，并且 在营养有限的情况下，  Rhinanthus的表现会更好。