In 1-2 sentences, What is a benefit that beavers have on the river ecosystem? What would be an effect of removing beavers from that ecosystem?

One benefit of beavers in the river ecosystem is that they create dams and ponds which can help regulate water flow and filter out pollutants. If beavers were removed from the ecosystem, there could be an increase in erosion and a decrease in biodiversity due to the loss of their habitat.