[saalweachter]

Niches changing is pretty boringly normal.

Dolphins are evolutionarily unfit to occupy the niche they had back on land. The bacteria that precipitated the oxygen crisis were very successful until they weren't.

There are many reasons to care about environmental destruction, pollution, and the loss of biodiversity, but at the same time it's neither particularly rational nor natural to obsess about preserving exactly the niches which existed at a particular point in time, nor our fitness for them.