Plant functional diversity as an important mediator of invasive effects on productivity in riparian grasslands

• Published in: Biological invasions Vol. 27; no. 5; p. 128
• Main Authors: Zheng, Jie, Li, Changxiao
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.05.2025
• Subjects: aboveground biomass; belowground biomass; Biodiversity; Biological invasions; Biomass; Canyons; Community composition; community structure; Ecological function; Ecosystems; equations; functional diversity; Grasslands; Invasive plants; invasive species; Plant communities; Plant diversity; Productivity; Riparian ecology; Species diversity; variance
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-025-03586-5

Plant invasions pose global challenges that significantly diminish ecosystem function through both the direct effects of invader abundance and the cascading consequences on species diversity (SD) and functional diversity (FD). However, in invasion-prone riparian ecosystems, how SD and FD influence ecosystem productivity across different invasion intensities remains unclear. Here, we evaluated the effects of plant invasions on SD, FD, aboveground biomass (AGB), and belowground biomass (BGB) using data from invasive plant communities in the Three Gorges Reservoir Area (TGRA), and elucidated the relationships among plant invasions, elevation (as a proxy for flood stress), biodiversity, and biomass using structural equation modeling (SEM). The results showed that plant invasions exert positive, neutral, or negative impacts on plant diversity, while their effects on AGB and BGB follow the nonlinear relationship that peaks at moderate invasion levels. SD and FD contributed differently to AGB and BGB across different invasion intensities, with moderate invasions enhancing the positive effects of plant diversity on AGB and BGB. Our SEM explained 64% of AGB variance and 23% of BGB variance, with plant invasions and elevation indirectly affecting both through FD. Additionally, SD and community composition influence AGB and BGB indirectly, primarily mediated through FD, rather than exerting direct effects. Our results indicate that plant invasions modulate the plant diversity–biomass relationship, underscoring FD as a crucial mediator of invasion effects on productivity within the flood regimes of the TGRA. This study offers novel insights into diversity-productivity relationships and provides practical guidance for managing invasive plants in riparian ecosystems.