The effects of natural enemies on herb diversity in a temperate forest depend on species traits and neighbouring tree composition

Abstract

1. 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.2. 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.3. 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.4. 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 arbuscularmycorrhizal (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. 5. 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.

Rhizosphere fungal community assembly varied across functional guilds in a temperate forest

“…The understory also had a dense and diverse assemblage, including herbs and mosses. The herb assemblage was dominated by Meehania urticifolia, Anemone amurensis, and Cardamine leucantha (Jia et al 2022). Most of these herbaceous species are known to form arbuscular mycorrhizas (AM), and other species do not associate with mycorrhizal fungi.…”

Analysis on the control of the black tiger shrimp in the America from the perspective of international cooperation

“…Black tiger shrimp have a variety of natural enemies and whether or not they harm the ecosystem depends on the characteristics of the ecosystem itself. If appropriate natural enemies are introduced based on the local ecosystem in the United States, then there will be no impact on the local ecosystem [19]. When considering the introduction of natural enemy, a full scientific assessment and management plan must be carried out.…”

The Chinese Forest Biodiversity Monitoring Network: 20-year achievements and outlook

“…群落组成与森林结构存在明显差异 (郝占庆等, 2008; 兰国玉等, 2008; 祝燕等, 2008; 刘海丰等, 2011; 杨 庆松等, 2011; 徐丽娜和金光泽, 2012; 王斌等, 2014; 张觅等, 2014; 宋永昌等, 2015 Mi et al, 2012;Liu et al, , 2021Wang et al, 2013;Zhu et al, 2017;Jia et al, 2018Jia et al, , 2020Jia et al, , 2022Mao et al, 2019Mao et al, , 2023…”