Аудирование TOEFL

🎧 Транскрипт аудио

Listen to part of a lecture in an environmental science class. The professor is discussing the role of beavers in ecosystems. Professor: Today we're going to talk about beavers and their surprising impact on river ecosystems. When beavers build dams, they create ponds that slow down the water flow. This not only provides a safe habitat for the beavers themselves, but it also benefits many other species. For example, the still water attracts frogs, insects, and fish, which in turn draw birds and mammals. Additionally, the dams trap sediment, which improves water quality downstream. However, beavers can also cause problems. Their flooding can damage roads and farmland, leading to conflicts with humans. In some areas, wildlife managers have tried to solve this by installing flow devices—pipes that control water levels without removing the dams. These devices allow beavers to stay, while reducing property damage. Interestingly, studies show that beaver ponds also help store carbon and can mitigate the effects of drought. So, despite initial challenges, beavers are now seen as a key species for ecosystem restoration.