Plant Invasion Driven by Heavy Metals and Microplastics: From Mechanisms to Agroecological Management Implications

Biological invasions and environmental pollution are the two primary threats facing contemporary agricultural ecosystems, and their interaction exacerbates agroecological risks and undermines agricultural sustainability. This study was conducted to systematically elucidate how heavy metals (HMs) and microplastics (MPs) alter the relative advantages of invasive plants in ecosystems, clarify the ecological processes involved, and propose recommendations for the protection of farmland ecosystems. The main conclusions are as follows: (1) Pollution acts as an environmental filter that negatively affects native species, including crops, while creating relative advantages for invasive plants with high tolerance and adaptive physiological mechanisms. (2) Pollution stress enables invasive plants to gain a competitive advantage over native plants through highly plastic resource allocation strategies, prioritization of growth, and more powerful allelopathic effects. (3) Pollution systematically amplifies the advantage of invasive plants by altering the strength of plant–soil feedback (PSF) and driving the restructuring of rhizosphere microbial communities. (4) Invasive plants can be used to produce biochar, which can then be applied in farmland ecosystems for the control of invasive plants and remediation of soil pollution. The framework constructed in this study indicates that heavy metal and microplastic pollution may enhance the invasion of alien plants, posing a serious threat to agroecosystem health and food security. However, using invasive plants as feedstock to produce biochar may offer a solution to the intertwined challenges of plant invasion and environmental pollution.