TOEFLリスニング

🎧 リスニング原文

Listen to part of a lecture in an environmental science class. The professor is discussing the role of beavers in ecosystems. 'Today, we're going to talk about an animal that is often overlooked in its importance to the environment: the beaver. Beavers are what we call 'ecosystem engineers.' Unlike many animals that simply adapt to their surroundings, beavers actively modify their habitats to suit their needs. By building dams across streams, they create ponds, which provide them with protection from predators and a place to store food for the winter. But the benefits go far beyond the beavers themselves. These ponds slow down the flow of water, allowing sediment to settle and pollutants to be filtered out. This can improve water quality downstream. Moreover, the flooded areas create wetlands that support a rich diversity of plant and animal life. In fact, the number of species can increase dramatically in areas where beavers are active. However, beavers were once hunted nearly to extinction for their fur. Their recent comeback has sparked debates among landowners, some of whom see them as a nuisance due to flooding of their property. Nonetheless, many ecologists argue that the reintroduction of beavers is a cost-effective and natural way to restore river ecosystems.'