Beavers reshape entire landscapes so thoroughly they change the local climate

A beaver dam turns a flowing stream into a pond, drowning some trees while creating wetland habitat that supports far more species than the stream alone ever did. The ponds trap sediment, recharge groundwater, and buffer against both drought and flood, effects that persist for decades after the beavers themselves move on. Ecologists call them a keystone species precisely because removing them collapses habitat that dozens of other species quietly depend on.

— Ben Goldfarb, Eager: The Surprising, Secret Life of Beavers and Why They Matter — 2018
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