When invaders collude: diverse invasive plants intensify allelopathy through positive net diversity effects

doi:10.1093/jpe/rtag175

J Plant Ecol ›› Advance articles DOI:10.1093/jpe/rtag175

• Research Article • Next Articles

When invaders collude: diverse invasive plants intensify allelopathy through positive net diversity effects

Baisheng Ren^ab, Mingyan Li^ab, Zhenwei Xu^c, Yi Hu^d, Qiang Wang^e, Zhihang Sun ^ab, Yu Liang^ab, Yijin Wang^ab, Tianji Zhang^ab, Dasheng Liu^f, Shaoxia Guo^ab, Xiao Guo^ab*

a College of Landscape Architecture and Forestry, Qingdao Agricultural University, No. 700 Changcheng Road, Qingdao 266109, P.R. China
b College of Landscape Architecture and Forestry, Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Qingdao Agricultural University, Qingdao, 266109 Shandong, China
c Institute of Ecology, College of Urban and Environmental Science, and State Key Laboratory for Vegetation Structure, Function and Construction (VegLab), Peking University, Beijing, P.R. China
d Qingdao Key Laboratory of Ecological Protection and Restoration, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
e Shandong provincial forestry protection and development service center, No. 5948 East Second Ring Road, Jinan City, Shandong Province, P.R. China
f Ecological Society of Shandong, Yingxian Jie19, Jinan 250012, China
* Corresponding author:
Xiao Guo, PhD, Professor
xiaoguoyeah@yeah.net
ORCID: https://orcid.org/0000-0003-2268-5090
Tel: +86 0532 58957693

Received:2026-01-29 Accepted:2026-07-15 Published:2026-07-29
Supported by:
The research was supported by National Natural Science Foundation of China (No. 32271588), Natural Science Foundation of Shandong Province, China (No. ZR2025QC190), Key Laboratory of Jiangxi Province for Biological Invasion and Biosecurity (No. BIB202501) and Qingdao Agricultural University Doctoral Start-Up Fund (No. 6631120094).

Abstract

Abstract: Allelopathy is a key mechanism by which invasive plants suppress native species to gain competitive advantage. However, most studies have focused on the allelopathic effects of individual invasive species, while paying little attention to how allelochemicals from multiple invaders jointly affect native plants under multi-species invasion scenarios that commonly occur in both natural and urban ecosystems. The invasional meltdown hypothesis predicts that co-occurring invaders can intensify suppression of natives, but mechanistic studies—especially from a multi-invader allelopathy perspective—are scarce. We selected five invasive plant species widely distributed in temperate and subtropical China and three native species coexisting with them. Aqueous leachates were prepared from invasive plants, and treatments were established with five source-species diversity levels and three concentration levels. We measured seed germination and seedling growth of each native species under different leachate treatments. Our results show that single-species leachates generally inhibited native growth, although some species exhibited highdose inhibition but lowdose stimulation (hormesis). In multi-species treatments, allelopathic suppression at high leachate concentrations increased significantly with source-species diversity, whereas at low concentrations, mixtures of leachates from either two species or multiple species enhanced both seedling height and fresh weight. Invasive plant diversity strengthened allelopathic suppression likely through complementarity effects rather than selection effects. High invasive plant diversity also amplified the hormesis of mixed allelochemicals on native species. By integrating the novel weapons hypothesis with the invasional meltdown hypothesis, this study provides new mechanistic explanations and experimental evidence for synergistic interactions in multi-species invasions, offering insights for managing ecosystems invaded by multiple species.

This study found that invasive plant diversity can significantly enhance the allelopathic suppression of native plants through biodiversity effects, particularly the complementarity effect, thereby promoting the success of multispecies co-invasion by alien plants.

Key words: Allelopathy, Multi-species invasion, Biodiversity effects, Synergistic effect, Hormesis, Invasional meltdown hypothesis

Baisheng Ren, Mingyan Li, Zhenwei Xu, Yi Hu, Qiang Wang, Zhihang Sun, Yu Liang, Yijin Wang, Tianji Zhang, Dasheng Liu, Shaoxia Guo, Xiao Guo. When invaders collude: diverse invasive plants intensify allelopathy through positive net diversity effects[J]. J Plant Ecol, DOI: 10.1093/jpe/rtag175.

[1]	Yanwen Bo, Yali Liao, Mark Pawlett, Rasheed Akbar, Nickolas Girkin, Jianfan Sun, Amjad Ali, Naushad Ahmad, Wei Liu, Xiaoyan Wang, Daolin Du. Solidago canadensis modifies microbial community and soil physicochemical properties through litter leachates and root exudates [J]. J Plant Ecol, 2025, 18(2): 1-14.
[2]	Xiaoyan Chen, Zhengchuan Liang, Yun Long, Jihong Pan, Tingfa Dong, Qinsong Liu, Xiao Xu. Effects of water extract from Cornus controversa on the expression levels of DiSOC1-b and DiCCoAOMT1 genes related with the growth of dove tree seedlings [J]. J Plant Ecol, 2024, 17(2): 0-rtae009.
[3]	Qiang Guo, Ruo-Hui Zhang, Xue-Li Li, Xiao-Wei Liu, Ya-Nan Li and Fu Xing. Nitrogen addition overrides the effects of Stellera chamaejasme litter on the growth of Leymus chinensis and its associated mycorrhizal fungi [J]. J Plant Ecol, 2022, 15(5): 1007-1020.
[4]	Lei Pu, Lang Cheng, Ai Li, Sha Liang, Qing Wei, Shulan Wu, Linxuan He, Xiangning Xu, Ningfei Lei and Jinsong Chen. Effects of clonal integration on allelopathy of invasive plant Wedelia trilobata under heterogeneous light conditions [J]. J Plant Ecol, 2022, 15(3): 663-671.
[5]	Věroslava Hadincová, Hana Skálová and Zuzana Münzbergová. Genotypic diversity and genotype identity of resident species drive community composition [J]. J Plant Ecol, 2020, 13(2): 224-232.
[6]	Benjamin D. Jaffe, Michael E. Ketterer, Stephen M. Shuster. Elemental allelopathy by an arsenic hyperaccumulating fern, Pteris vittata L. [J]. J Plant Ecol, 2018, 11(4): 553-559.
[7]	Lisette M. Bakker, Liesje Mommer, Jasper van Ruijven. Can root trait diversity explain complementarity effects in a grassland biodiversity experiment? [J]. J Plant Ecol, 2018, 11(1): 73-84.
[8]	Paula Lorenzo, Jonatan Rodríguez, Luís González, Susana Rodríguez-Echeverría. Changes in microhabitat, but not allelopathy, affect plant establishment after Acacia dealbata invasion [J]. J Plant Ecol, 2017, 10(4): 610-617.
[9]	Bin Zhu, Samuel E. Georgian2. Interactions between invasive Eurasian watermilfoil and native water stargrass in Cayuga Lake, NY, USA [J]. J Plant Ecol, 2014, 7(6): 499-508.
[10]	Yongge Yuan, Bing Wang, Shanshan Zhang, Jianjun Tang, Cong Tu, Shuijin Hu, Jean W. H. Yong, Xin Chen. Enhanced allelopathy and competitive ability of invasive plant Solidago canadensis in its introduced range [J]. J Plant Ecol, 2013, 6(3): 253-263.
[11]	Terezie Stachová, Pavel Fibich, Jan Lepš. Plant density affects measures of biodiversity effects [J]. J Plant Ecol, 2013, 6(1): 1-11.
[12]	Luca Wacker, Oksana Baudois, Susann Eichenberger-Glinz, Bernhard Schmid. Effects of plant species richness on stand structure and productivity [J]. J Plant Ecol, 2009, 2(2): 95-106.
[13]	D. Abhilasha, J. Joshi. Enhanced fitness due to higher fecundity, increased defence against a specialist and tolerance towards a generalist herbivore in an invasive annual plant [J]. J Plant Ecol, 2009, 2(2): 77-86.
[14]	Stefanie von Felten, Bernhard Schmid. Complementarity among species in horizontal versus vertical rooting space [J]. J Plant Ecol, 2008, 1(1): 33-41.

When invaders collude: diverse invasive plants intensify allelopathy through positive net diversity effects

HTML

PDF

Knowledge

Abstract

Cite this article

share this article

References

Related Articles 14

Recommended Articles

Metrics

Comments