Invasive species can rewire the flows of nitrogen, carbon, phosphorus and other elements by changing inputs, altering decomposition rates, shifting microbial communities and modifying disturbance regimes. Research by Paul Vitousek at Stanford University and David Tilman at the University of Minnesota demonstrates that these shifts are not incidental: invasive plants and animals often change the balance between nutrient retention and loss, with consequences for productivity, water quality and native biodiversity. These effects are often context-dependent, varying with climate, soil type and the history of land use.
Mechanisms that change nutrient flows
Nitrogen fixation by introduced legumes and trees increases available nitrogen in soils where plants evolved under low-nitrogen conditions. Michael D. Richardson at Stellenbosch University and colleagues have documented how Australian acacias alter soil nitrogen in South African fynbos, facilitating further invasions and favoring fast-growing species. Invasive grasses studied by Deborah D'Antonio at the University of California, Davis accelerate nutrient turnover through high-quality litter that decomposes rapidly, releasing nutrients and promoting frequent fires. In wetlands, invasive reed Phragmites australis has been shown by Cynthia Saltonstall at the U.S. Geological Survey to change organic matter accumulation and redox conditions, affecting carbon and nitrogen storage. Nonplant invaders such as earthworms rework leaf litter and mineral soils, increasing mineralization and altering microbial pathways that control nutrient availability.
Microbial shifts are central. When invaders modify root exudates or litter chemistry they select for different bacterial and fungal assemblages, which in turn change rates of nitrification, denitrification and carbon mineralization. These changes can increase nitrate leaching and gaseous nitrogen losses or, conversely, sequester nutrients in forms less available to native species. Research by David Tilman links such shifts to declines in native plant diversity, because altered nutrient regimes favor a subset of opportunistic species.
Consequences for ecosystems and people
Altered nutrient cycling cascades into ecological and human consequences. Elevated nitrogen availability can lead to algal blooms and hypoxia in downstream waters, reducing fisheries and compromising drinking water sources. Intensified fire regimes driven by nutrient-fueled grasses change cultural landscapes and threaten infrastructure and traditional land uses. Daniel Simberloff at the University of Tennessee has documented how invasions impose economic costs on agriculture, fisheries and forest management through changed productivity and increased control expenses.
Restoration is challenging because nutrient legacies persist after invaders are removed; soils and microbes may continue to favor nonnative species. Effective management thus requires combining removal with interventions that restore nutrient balance and native plant communities, informed by long-term monitoring and local ecological knowledge. Recognizing the cultural and territorial dimensions of invasions—how introductions often trace to trade, colonization and land-use change—improves prevention and community-led responses.
Understanding the mechanistic links between invasive species and nutrient cycling, as shown by researchers at Stanford University, the University of Minnesota and other institutions, helps prioritize actions that reduce ecological harm while respecting social and cultural contexts. Managing nutrient feedbacks as well as populations of invaders is essential for restoring resilient ecosystems.