What is the effect of invasive species introduction on ecosystem dynamics?

• A. Invasive species introduction can disrupt interactions, reduce biodiversity, and shift energy flow.
• B. Invasive species always increase native biodiversity.
• C. Invasive species have no effect.
• D. Invasive species only affect plants.

Answer: (A)

When invasive species enter an ecosystem, they often upset how the system works by changing who eats whom, how resources are used, and how energy moves through the community. An invader may outcompete native species for food, space, or habitat, leading to declines or losses of native populations. With fewer native species, the web of interactions—predation, pollination, competition, and mutualisms—shifts, which can cascade through the food web and alter overall ecosystem function.

In addition, invasive species can change energy flow and nutrient cycling. For example, a new predator can reduce populations of certain prey, rebalancing energy transfer between trophic levels; a plant invader can alter plant communities and fire regimes or decomposition rates, further changing how energy and nutrients move through the ecosystem. It’s these changes in interactions and energy pathways that often reduce biodiversity and reconfigure ecosystem dynamics.

Some choices aren’t accurate because invasive species do not consistently boost native biodiversity, they can have no effect only in special cases, and they do not affect only plants—animals, microbes, and abiotic processes can all be impacted.