In the Pacific Northwest, beavers increase resilience to wildfire and drought. They do so by creating natural fire breaks and by increasing groundwater storage. They also do this in a way that also creates fish habitat and deeper pools that coldwater fish like trout and salmon can take advantage of to survive lower water years.

They're really ecologically important, and while some may complain that they fall trees, that's actually very beneficial in the west where we have forest fires that burn far more trees than any beavers could hope to destroy to build their structures. This is not just for the northwest, but other drought and fire-prone western regions (Oregon, Colorado).

TL;DR Our elimination of beavers is exacerbating the problems of drought and fire in the american west.

Good video from PBS's Terra series: https://www.youtube.com/watch?v=6lT5W32xRN4