Biology Regents Practice Exam

What impact did the introduction of the emerald ash borer have on ecosystems?

1. It increased biodiversity in the area

2. It helped control a pest population

3. It altered the equilibrium in an ecosystem

4. It removed invasive plant species

The correct answer is: It altered the equilibrium in an ecosystem

The introduction of the emerald ash borer significantly altered the equilibrium in ecosystems where it has established populations. This invasive species targets ash trees, causing widespread mortality and leading to dramatic changes in forest composition. When a keystone species like the ash tree is removed, it affects not just the trees themselves but also the various organisms that depend on them for habitat, food, and stability in the ecological community. As ash trees die off, other species of plants may become more prevalent or dominant, disrupting the existing balance. The loss of ash trees can also lead to changes in nutrient cycling and soil structure, further impacting various life forms, including insects, birds, and mammals that rely on the ash tree ecosystem. This cascading effect exemplifies how the introduction of a non-native species can disrupt established ecological relationships, creating a new equilibrium that differs significantly from the original state.