Impacts of Invasive Species on Forest Ecosystems

Invasive species represent one of the leading drivers of forest ecosystem change worldwide, affecting structure, function and the services forests provide to people and biodiversity. Through direct competition, novel herbivory and pathogen transmission, invasive plants, animals and microbes can reduce native species richness and alter successional trajectories. At the same time, invaders may disrupt nutrient cycling and soil properties, triggering feedbacks that favour further colonisation by non-native biota. Herbivorous invaders such as deer or pigs can modify understory composition and canopy regeneration through selective browsing or trampling, while invasive earthworms and pathogens undermine soil stability and nutrient retention. These combined effects can cascade across trophic levels, reshaping microclimate, hydrology and carbon storage potential. Under changing climates, the rapid range shifts of invaders compound pressures on stressed native forests, sometimes leading to ‘invasional meltdown’ in which multiple non-native species interact synergistically to exacerbate ecological degradation. Yet not all non-native species exert uniformly negative impacts; some may partially replace lost ecosystem functions in novel forests. An integrated view of aboveground-belowground interactions, co-invasion dynamics and context dependency is essential to predict trajectories of invaded forests and to design adaptive management strategies. Restoration efforts increasingly combine mechanical removal, biological control and reintroduction of native species, aiming to re-establish soil-plant feedbacks and enhance resilience to future invasions.

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Impacts of Invasive Species on Forest Ecosystems publication trend

The graph below shows the total number of articles in impacts of invasive species on forest ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Aboveground–belowground interactions: Reciprocal effects between soil communities (microbes, invertebrates) and plant or animal assemblages that shape nutrient cycling and ecosystem structure.

Invasional meltdown: A process in which multiple invasive species facilitate one another’s establishment and intensify ecological impacts.

Species distribution model: A predictive tool that relates occurrence data to environmental variables to forecast potential ranges of species.

Invasibility: The susceptibility of a habitat to invasion, determined by factors such as disturbance regime, resource availability and resident community composition.

References

1. Impacts of invasive biota in forest ecosystems in an aboveground–belowground context. Biological Invasions (2017).
2. Contrasting ecological roles of non-native ungulates in a novel ecosystem. Royal Society Open Science (2018).
3. Modeling Hawaiian Ecosystem Degradation due to Invasive Plants under Current and Future Climates. PLOS ONE (2014).