[SoothingDave]

Yes, beavers cut down trees and change the environment, but they change it from one type of habitat with diverse lifeforms to another type of environment with many other lifeforms. When we build cities the resulting habitat really only suits humans, rats, cockroaches, feral cats and dogs, and sometimes coyotes.

I'm guessing you don't see your own internal irony.

Unless you don't consider, man, rats, cockroaches, etc. to be "diverse lifeforms."

SD

[ahayes]

Diversity refers to type as well as number. A habitat that supports only six species is woefully lacking in diversity.

[nuke rocketeer]

Fire ant cities (nests) are amenable only to fire ants. These critters are a bigger threat to wildlife diversity than humans any day. Does this also disqualify them as not "natural". Think of all the other ant species, ground nesting birds, ground insects, newborn fawns, calves, lambs, and reptiles they push out of a place they invade.