TOEFL Integrated Writing

📖 Reading Passage

The concept of 'rewilding'—restoring ecosystems by reintroducing large predators and allowing natural processes to resume—has gained traction among conservationists. Proponents argue that rewilding can restore ecological balance, boost biodiversity, and mitigate climate change. First, reintroducing apex predators like wolves can control herbivore populations, preventing overgrazing and allowing vegetation to recover. For example, in Yellowstone National Park, wolf reintroduction led to increased tree regeneration and a cascade of positive effects on other species. Second, rewilding enhances biodiversity by creating habitats for a wider range of organisms. Large predators and their prey create carcasses that support scavengers, and their movements disturb soil, promoting plant diversity. Third, rewilding can aid carbon sequestration. Healthy, restored ecosystems with diverse plant life and thriving soil microbial communities can absorb more carbon dioxide than degraded landscapes, thus helping to offset emissions. These benefits suggest that rewilding is a cost-effective and sustainable strategy for environmental restoration.

🎧 Listening Lecture

While the reading touts rewilding's benefits, the lecture challenges these claims with evidence from recent studies. First, the Yellowstone wolf recovery is often overstated. The observed tree regeneration was largely due to other factors—such as reduced elk populations from human hunting and drought conditions—not solely wolf predation. In other regions, wolf reintroduction has failed to produce similar cascades, indicating that the effect is context-dependent and not universally applicable. Second, rewilding does not always boost biodiversity. In some cases, reintroduced predators can decimate prey species that have no natural defenses, leading to local extinctions. For instance, attempts to reintroduce lynx in Scotland have threatened ground-nesting bird populations, reducing overall diversity. Third, the carbon sequestration claim is speculative. Restored ecosystems may take decades to become carbon sinks, and during initial stages, they can actually release carbon due to soil disturbance and decomposition of existing vegetation. Moreover, the most effective carbon sinks are often mature old-growth forests, which rewilding does not directly create. Thus, rewilding's promised ecological and climatic benefits are uncertain and may not justify its high costs.