Increased traffic volume threatens plant–pollinator interactions and plant reproductive success

Abstract

1. Roads represent one of the most widespread forms of human infrastructure.Their presence, along with associated vehicle traffic, fragments ecosystems anddisrupts plant–pollinator interactions. However, the precise mechanisms throughwhich these disturbances cascade to reorganise plant–pollinator interaction net-works and ultimately affect plant reproduction remain poorly understood.2. In this study, we investigated how traffic volume (low vs. high) affects plant–pol-linator communities, interaction networks and plant reproductive success alongspatial gradients extending from roads in alpine meadows of the Tibetan Plateau.3. Using piecewise structural equation modelling, we found that high traffic volumereduced flower richness, which subsequently lowered pollinator abundance andrestructured interaction networks—characterised by decreased connectance, in-creased nestedness and heightened specialisation—ultimately leading to lowercommunity-level plant reproductive success. These adverse impacts diminishedwith increasing distance from roads, suggesting a spatial buffering effect in road-side ecosystems.4. Synthesis. Our findings demonstrate that high traffic volume triggers cascadingeffects that disrupt mutualistic networks and undermine pollination services infragile ecosystems. To conserve biodiversity and sustain ecosystem resilience, it isessential to incorporate pollination dynamics into roadside management. Practicalmeasures such as establishing vegetative buffer zones and actively enhancing floralresources should be prioritised across existing and expanding road networks.