Question

Which of these is MOST LIKELY to contribute to the long-term instability of a local ecosystem?
Responses
A storms that uproot large trees in the areastorms that uproot large trees in the area
B introduction of a non-native animal speciesintroduction of a non-native animal species
C seasonal migration of birds to and from the ecosystemseasonal migration of birds to and from the ecosystem
D flash floods that destroy the nests of local water birdsflash floods that destroy the nests of local water birds
E a fast burning wildfire

Answer 1

B

Introduction of a non‑native (invasive) species is most likely to cause long‑term instability. Invasives can outcompete or prey on native species, introduce diseases, alter food webs and nutrient cycles, and persist or spread over many years. The other options are typically short‑term or part of natural cycles (storms, floods, migration, or fire regimes that ecosystems may recover from or be adapted to).