Root hemiparasites and plant diversity in experimental grassland communities
Root hemiparasites and plant diversity in experimental grassland communities
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DOI：
10.1046/j.1365-2745.2000.00487.x
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发表时间：
2000-08-01
影响因子：
5.5
通讯作者：
Schmid, B
中科院分区：
文献类型：
--
作者：
Joshi, J;Matthies, D;Schmid, B
1研究了草原群落多样性与半寄生植物金丝桃的作用关系。我们比较了寄生群落对感染造成的生物量损失的抗性、寄生虫的表现以及寄生群落对其他植物入侵的抵抗力。将寄生虫的种子播种到含有1、2、4、8或32种植物的试验区，这些植物属于三个功能类群(草、豆类和非豆科草本植物)中的一个或多个。2我们预测，感染将降低寄主生物量、群落总生物量和对入侵的抵抗力，特别是在多样性较低的寄主群落，但寄生虫的表现将在此类群落中处于较低水平。3寄生虫的存在导致每块土地的寄主生物量总体下降，这主要是由于牧草生物量的大幅下降。正如预测的那样，在功能多样性较大的社区，影响较小。而寄主种群的总生物量(包括寄主生物量)增加了1/3以上，而寄主群落的总生物量变化不大。4寄主群落的多样性几乎不影响寄主群落的萌发，但早期存活率随功能基团数量的增加而降低，豆类小区的早期存活率低于无功能基团的小区。然而，我们的假设是存活的寄生虫的表现将受益于宿主的高度功能多样性，这一假设得到了支持。寄生虫的个体生物量和每m(2)生物量随着寄主社区中功能群数量的增加而增加，繁殖潜力也是如此。5寄生虫的死亡导致社区中裸露地面的比例较高，因为以前受感染的社区的功能多样性较低，因此能够随后被杂草殖民。
1 We studied the relationship between the diversity of grassland communities and the effects of the generalist hemiparasitic plant Rhinanthus alectorolophus. We compared resistance against biomass loss as a consequence of infection, performance of the parasite and resistance of the parasitized communities to invasion by other plant species. Seeds of the parasite were sown into experimental plots containing 1, 2, 4, 8 or 32 plant species belonging to one or more of three functional groups (grasses, legumes and non-leguminous herbs).2 We predicted that infection will reduce host biomass, total community biomass and resistance to invasion, particularly in host communities with low diversity, but that the performance of the parasite will be at its lower level in such communities.3 The presence of the parasite caused an overall reduction in host biomass per plot, which was mainly due to a strong reduction in the biomass of grasses. as predicted, the effect was smaller in communities with greater functional diversity. However, total community biomass (including the parasite biomass) was increased by more than a third in infected communities of one or two host species, while the parasite had no effect on total biomass of species-rich communities.4 Germination of the parasite was hardly influenced by the diversity of its host community, but early survival decreased with increasing number of functional groups and was lower in plots with legumes than without. However, our hypothesis that the performance of the surviving parasites would benefit from a high functional diversity of hosts was supported. Parasite biomass per individual and per m(2) increased with the number of functional groups in the host community, as did reproductive potential.5 Death of the parasite led to a higher proportion of bare ground in communities when the previously infected communities had low functional diversity, thus enabling subsequent colonization by weeds.