Non-native plants’ mycorrhizal strategies shift across biomes and disturbance levels

A global study has challenged one of ecology’s most persistent assumptions about invasive plants: that their success is consistently powered by a special relationship with soil fungi. The research, published in Nature Ecology & Evolution, finds that the mycorrhizal strategy of non-native plants changes markedly across biomes and disturbance regimes. In other words, the fungal partnerships associated with plant roots do not provide a universal invasion formula. Their importance appears to depend on where a plant arrives, what kind of ecosystem it enters and how strongly that ecosystem has been altered.

Mycorrhizae are symbiotic associations between fungi and plant roots. The fungi extend microscopic filaments, known as hyphae, through the soil, effectively increasing the root system’s reach. In exchange for carbon compounds produced through photosynthesis, the fungi can improve access to phosphorus, nitrogen, water and micronutrients. The relationship may also influence plant health by affecting pathogens, soil structure and interactions with other microorganisms. Most land plants form some type of mycorrhizal association, but the identity, strength and ecological consequences of those partnerships vary widely.

The new work focuses on how these associations relate to non-native plants across environmental contexts rather than treating all invasions as ecologically identical. That distinction is crucial because a plant introduced into a dry grassland faces a different set of constraints from one arriving in a tropical forest, temperate woodland or nutrient-poor island ecosystem. Soil chemistry, climate, native vegetation, fungal communities and land-use history can all determine whether a fungal partnership is beneficial, neutral or even costly. The study’s central message is that mycorrhizal strategy must be interpreted geographically and ecologically, not as a fixed trait of “invasive plants.”

One of the most important variables is biome. A biome is defined by broad combinations of climate, vegetation and ecological processes, and each biome supports distinctive communities of soil fungi. In some environments, forming a close association with fungi may help an introduced plant obtain scarce nutrients or tolerate drought. In others, the plant may gain little from the local fungal community, or it may prosper by investing less in symbiosis and more in rapid growth, reproduction or dispersal. This flexibility means that the same plant lineage can encounter very different underground opportunities after crossing a continent or entering a new climatic zone.

Disturbance adds another layer of complexity. Fire, cultivation, grazing, road construction, urbanization and repeated soil disruption can remove vegetation, alter nutrient cycles and break apart established fungal networks. Disturbed ground is often described as a blank slate for invaders, but it is rarely biologically empty. It may contain resilient fungal propagules, newly introduced microbes or a simplified community dominated by organisms adapted to rapid environmental change. Under such conditions, plants with different mycorrhizal requirements may experience contrasting advantages. A disturbance can weaken native plant–fungus partnerships while creating opportunities for non-native plants that are compatible with a broader range of fungi.

The findings therefore complicate the popular “invasive plants bring their own fungi” narrative. Some introduced plants may associate with fungal partners from their original range, a process sometimes called symbiont introduction. Others may recruit native fungi already present in the invaded ecosystem. Still others may shift between fungal partners depending on soil conditions. These pathways can influence establishment, but none should be assumed to dominate everywhere. The ecological outcome may depend on whether the plant’s fungal partners are available, whether they provide meaningful nutritional benefits and whether native plants already occupy the most productive symbiotic networks.

This context is especially important for predicting biological invasions. Management strategies sometimes treat mycorrhizal fungi as a single lever: remove them, add them or manipulate them to control plant spread. The study suggests that such interventions could produce inconsistent results. Suppressing fungal activity might hinder a non-native plant in one habitat but have little effect in another, particularly if the plant can switch partners or grow effectively without a strong symbiosis. Conversely, introducing beneficial fungi to support restoration could unintentionally assist non-native species if the ecological conditions favor them. Effective management will require information about local fungal communities, disturbance history and the specific mycorrhizal biology of both native and introduced plants.

The research also carries a broader warning about how ecological traits are used in large-scale analyses. Labels such as “mycorrhizal” or “non-mycorrhizal” compress a dynamic relationship into a simple category, even though fungal associations can change with plant age, soil fertility, season and climate. A plant may form abundant fungal connections but receive limited nutritional benefit, while another may depend heavily on fungi despite showing a less visible association. Future invasion forecasts may become more accurate when they incorporate the flexibility of these partnerships, the distribution of fungal symbionts and the ways global change is reshaping disturbance patterns. The underground biology of invasion is not a single story repeated worldwide; it is a shifting interaction between plants, fungi and place.

By showing that the mycorrhizal strategy of non-native plants varies with biome and disturbance, Cazzaniga, Lauber, van den Hoogen and colleagues move the debate beyond the idea that one hidden biological advantage explains invasion success. Their work points toward a more conditional model, in which fungal partnerships can help, fail to matter or change direction depending on environmental circumstances. As ecosystems experience intensifying land use, climate disruption and the movement of species across continents, understanding those conditions could become essential. The next generation of invasion science may depend as much on mapping fungal networks beneath the soil as on tracking plants above it.