What are invasive species, and what consequences can they have on ecosystem dynamics?

What are invasive species, and what consequences can they have on ecosystem dynamics?

• A. Invasive species are non-native species that spread rapidly; they can outcompete natives, alter trophic interactions, and disrupt energy/nutrient flows
• B. They are native species that become predators
• C. They are non-native but do not affect ecosystems
• D. They are non-native species that only affect plants, not animals

Answer: (A)

Invasive species are non-native organisms that spread rapidly in a new environment. Because they arrive without the natural checks present in their home range, they often outcompete native species for resources like food and habitat. This competition can shift who eats whom, reconfiguring food webs and altering predator–prey relationships. As the community composition changes, energy and nutrient flows through the ecosystem are disrupted—different species have different effects on processes like production, decomposition, and nutrientcycling. The overall result is changes in biodiversity and ecosystem functioning. This description fits best because it highlights the non-native status, rapid spread, competitive effects on natives, and the broad disruption to trophic interactions and energy/nutrient dynamics. The other statements miss important aspects: native predators don’t define invasives, invasives can and do affect ecosystems, and many invasives impact animals as well as plants, not just one group. For example, zebra mussels can alter water clarity and disrupt native aquatic communities, illustrating how invasive species ripple through energy and nutrient flows.

Invasive species are non-native organisms that spread rapidly in a new environment. Because they arrive without the natural checks present in their home range, they often outcompete native species for resources like food and habitat. This competition can shift who eats whom, reconfiguring food webs and altering predator–prey relationships. As the community composition changes, energy and nutrient flows through the ecosystem are disrupted—different species have different effects on processes like production, decomposition, and nutrientcycling. The overall result is changes in biodiversity and ecosystem functioning.

This description fits best because it highlights the non-native status, rapid spread, competitive effects on natives, and the broad disruption to trophic interactions and energy/nutrient dynamics. The other statements miss important aspects: native predators don’t define invasives, invasives can and do affect ecosystems, and many invasives impact animals as well as plants, not just one group. For example, zebra mussels can alter water clarity and disrupt native aquatic communities, illustrating how invasive species ripple through energy and nutrient flows.