Global Meta-Analysis Reveals That Pollution Strongly Inhibits Seed-Based Regeneration of Wild Plants

Aim: Anthropogenic pollution is a pervasive driver of global change, yet its ecological impacts on wild plants remain relatively less synthesised, particularly for their regeneration. Quantifying how pollution, such as heavy metals, threatens seed-to-seedling transitions in wild plants is essential for understanding species persistence, community resilience, and vegetation dynamics under accelerating environmental pressures. However, the quantitative impacts of pollution on wild plant regeneration remain poorly understood at a broad scale. Location: Global. Time Period: 1990 to 2024. Major Taxa Studied: Wild plants. Methods: We conduct a global meta-analysis of 4476 experiments from 107 publications to quantify the effects of pollution on the earliest life stages of 162 wild plant species. Results: Pollution significantly inhibits wild plant seed-based regeneration by an average of one-third. Specifically, pollution reduces seed germination by 33%, prolongs germination speed by 29%, and suppresses seedling growth by 42%. Pollution also disproportionately suppresses below-ground growth of seedlings, altering root-to-shoot biomass allocation by 27%. While these inhibitory impacts are qualitatively consistent across species and pollutant types, pollutant type and concentration are more important quantitative predictors of these impacts than plant characteristics such as growth form and seed mass. Heavy metals exhibit a dual, concentration-dependent effect, with low concentrations (< 0.05 mg/L on average) facilitating regeneration and high concentrations severely impairing it. Main Conclusions: These findings suggest pollution acts as a powerful “regeneration filter”, favouring pollution-tolerant, often invasive, “winner” species over sensitive native “losers”, thereby reshaping community assembly and exacerbating biotic homogenisation. By quantifying this severe ecological bottleneck, our study provides quantitative evidence that pollution poses a pervasive threat to biodiversity, with impacts on a critical life stage rivalling other major drivers of global change. These findings underscore the urgent need to integrate pollution mitigation into conservation frameworks like the Kunming-Montreal Global Biodiversity Framework to safeguard ecosystem function and resilience.