The effects of large herbivore grazing on meadow steppe plant and insect diversity
The effects of large herbivore grazing on meadow steppe plant and insect diversity
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DOI：
10.1111/j.1365-2664.2012.02195.x
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发表时间：
2012-10
影响因子：
5.7
通讯作者：
Hui Zhu;Deli Wang;Ling Wang;Y. Bai;Jian Fang;Jun Liu
中科院分区：
文献类型：
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作者：
Hui Zhu;Deli Wang;Ling Wang;Y. Bai;Jian Fang;Jun Liu
Summary1。相邻营养级之间的相互作用对生态系统的功能和稳定至关重要。家养食草动物的放牧是草地上必不可少的相互作用，但关于大型食草动物放牧下植物和昆虫多样性之间关系的本质信息很少。在草甸草原3种植物多样性水平（低：4-5种，中：8-9种，高：15-17种）下，通过5种放牧方式（对照、牛、山羊、绵羊和3种放牧方式的混合），研究了大型食草动物对植物和昆虫多样性关系的影响。放牧处理对植物物种丰富度无显著影响，但降低了植物生物量、株高和盖度。不同植物多样性水平下，放牧动物对植物高度变化的影响不同，在低植物多样性水平下，这种变化增加，在高植物多样性水平下，这种变化减少。在昆虫物种丰富度方面，放牧对低植物多样性水平的影响为正，对高植物多样性水平的影响为负。在无放牧条件下，昆虫物种丰富度与植物物种丰富度呈显著正相关，但随着放牧条件下植物多样性的增加，昆虫物种丰富度与植物物种丰富度呈显著正相关。这与大型食草动物放牧条件下昆虫物种丰富度对植物高度异质性的强烈响应有关，说明在影响放牧草地昆虫多样性方面，植物结构异质性比植物多样性更为重要。合成与应用。大型食草动物的放牧可能通过改变植物结构异质性而逆转植物多样性与昆虫多样性之间的正相关关系。因此，在今后的植物-昆虫相互作用研究中，应重视植被结构的空间异质性。该研究进一步强调了在管理行动中使用大型食草动物的重要性，不仅可以保持多样性，还可以调节草原的营养相互作用。关键词：草地，放牧，昆虫物种丰富度，大型食草动物，植物物种丰富度，植物结构异质性，植物高度变异
Summary1. The interactions between adjacent trophic levels are essential for ecosystem functioning andstability. Grazing by domestic herbivores is an essential interaction in grasslands, but littleinformation is available on the nature of relationship between plant and insect diversity undergrazing by large herbivores.2. We examined the effects of large herbivores on the relationship between plant and insectdiversity with five grazing treatments (control, cattle, goat, sheep and a mixture of the threegrazing types) across three plant diversity levels (low: 4–5 species, intermediate: 8–9 speciesand high: 15–17 species) in a meadow steppe.3. We found that the grazing treatments did not significantly affect plant species richness, butreduced plant biomass, plant height and cover. Grazers affected variation in plant height dif-ferently at different plant diversity levels, and this variation increased at the low plant diver-sity level and decreased at the high plant diversity level after grazing. A similar pattern wasobserved for insect species richness: grazing had a positive impact at the low plant diversitylevel, but had a negative impact at the high plant diversity level.4. In the absence of grazing, insect species richness was positively associated with plant spe-cies richness, but it decreased with increasing plant diversity in the grazing treatments. Thiswas attributed to strong responses of insect species richness to plant height heterogeneityunder grazing by large herbivores, implying that plant structural heterogeneity is more impor-tant than plant diversity in influencing insect diversity in grazed grasslands.5. Synthesis and applications. Grazing by large herbivores may reverse the positive relation-ship between plant diversity and insect diversity by modifying plant structural heterogeneity.Therefore, the spatial heterogeneity of vegetation structure should be given more attention infuture work on plant–insect interactions. This study further highlights the importance ofusing large herbivore grazing in management actions, not only to maintain diversity but alsoto mediate trophic interactions in grasslands.Key-words: grassland, grazing, insect species richness, large herbivores, plant species rich-ness, plant structural heterogeneity, variation in plant heightIntroduction