Beavers are called ecosystem engineers by ecologists because the change their ecosystem by cutting trees present in their ecosystem and make dams over the river by these trees, dig channels and build lodges.
These dams alter the river flow and results in the formation of a lake which have still water. Over time many still water-loving animals and plants occupy the ponds and make a new ecosystem in that area. So by making dams beavers helps in increasing the biodiversity of the place.
So due to the capability of beavers to bring change in its ecosystem, they are called ecosystem engineers.
I found this: Castor<span> includes two extant species, the North American beaver (</span>Castor canadensis) (native<span> to North America) and</span>Eurasian<span> beaver (</span>Castor fiber<span>) (Eurasia). Beavers are known for building dams, canals, and lodges (homes). They are the second-largest </span>rodent<span> in the world (after the</span>capybara<span>).
