The effects of natural enemies on herb diversity in a temperate forest depend on species traits and neighbouring tree composition
The effects of natural enemies on herb diversity in a temperate forest depend on species traits and neighbouring tree composition
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DOI：
10.1111/1365-2745.13973
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发表时间：
2022-07
影响因子：
5.5
通讯作者：
Shihong Jia;Xugao Wang;Zhanqing Hao;Robert Bagchi
中科院分区：
文献类型：
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作者：
Shihong Jia;Xugao Wang;Zhanqing Hao;Robert Bagchi
越来越多的证据表明，天敌自上而下的控制有助于维持自然生态系统中的植物多样性。以前的工作集中在森林树木或草原草本植物上。我们对天敌如何影响森林中草本多样性的了解有限。我们使用杀菌剂和杀虫剂来实验研究真菌和昆虫对群落范围内以及具有某些性状的物种群体内草本丰度和多样性的影响。我们还评估了古老温带森林中邻近树木多样性和组成如何改变真菌和昆虫对药草组合的影响。我们发现杀菌剂使草本植物总体丰度增加了 7%，同时使草本植物多样性降低了 5%。杀菌剂对草本丰度和多样性的影响随着邻近树木多样性的增加而减弱。杀虫剂不会显着影响草本丰度或多样性，除了在以落叶树为主的地区，杀虫剂的施用降低了草本多样性。杀菌剂和杀虫剂降低了防御性相对较差的物种（即薄叶和非克隆）的多样性，但对防御性较强的草本植物（即厚叶和无性系）的多样性没有影响。杀菌剂增加了非菌根（NM）物种的丰度，但没有增加丛枝菌根（AM）物种的丰度，尽管杀菌剂对草本多样性的影响与物种的菌根关联无关。杀虫剂对NM物种的丰度和多样性的影响强于AM物种。合成。我们得出的结论是，真菌和昆虫食草动物对于调节这片温带森林的草本丰度和多样性至关重要，其影响取决于物种的性状和邻近树木的多样性和组成。我们的研究结果强调了温带森林中天敌对林下草本群落自上而下控制的重要性，增进了我们对自然生态系统中植物多样性形成过程的理解。
There is mounting evidence that top‐down control by natural enemies helps maintain plant diversity in natural ecosystems. Previous work has concentrated on either forest trees or grassland herbs. Our knowledge of how natural enemies affect herb diversity in forests is limited. We used fungicides and insecticide to experimentally examine the effects of fungi and insects on herb abundance and diversity at the community‐wide scale and within groups of species with certain traits. We also assessed how the effects of fungi and insects on herb assemblages were modified by neighbouring tree diversity and composition in an old‐growth temperate forest. We found that fungicides increased overall herb abundance by 7% while decreasing herb diversity by 5%. This effect of fungicides on both herb abundance and diversity weakened with the increase of neighbouring tree diversity. Insecticide did not affect either herb abundance or diversity noticeably, except in areas dominated by deciduous trees where insecticide application reduced herb diversity. Fungicides and insecticide decreased the diversity of relatively less defended species (i.e. thin‐leaved and non‐clonal) but had no effect on the diversity of herbs with stronger defensive traits (i.e. thick‐leaved and clonal). Fungicides increased the abundance of non‐mycorrhizal (NM) species but not arbuscular‐mycorrhizal (AM) species, although the effect of fungicides on herb diversity was unrelated to species' mycorrhizal association. Insecticide had stronger effects on the abundance and diversity of NM species than AM species. Synthesis. We conclude that fungi and insect herbivores are critical to regulating herb abundance and diversity in this temperate forest, with their effects dependent on species' traits and neighbouring tree diversity and composition. Our results highlight the importance of top‐down control of understory herb communities by natural enemies in temperate forests, advancing our understanding of the processes shaping plant diversity in natural ecosystems.