Isn't the point rather that the novelty itself isn't the degradation, but the disappearance of the other native species as they get replaced by other species which already exist elsewhere, thereby decreasing overal number of individual species should the native ones go extinct? You could then argue that less species isn't a degradation because on a huge timescale that might not matter. However on a more 'current' timescale, I'm not sure how else to treat the man-made huge biodiversity loss other than a degradation.
All I really hear is that some very small group of aesthetically-minded human apes are precious about one more variety of bird, against the interest of very many other human apes that need to eat.
If the new ecology were really extremely desolate, we might weigh up this a little differently, sure. But the article's entire analysis is that these new ecologies are genuinely "natural" in the sense of self-sustaining, and varied, and so on.
> we're losing access to genetic diversity that could be exploited now or in the future for medical treatments, innovations in science, etc.
The entire article presumes that novelty is a degradation -- yet offers no evidence for it. So it's just an article of faith that whatever series of major evolutionary catastrophes led to to an ecology are morally or aesthetically preferable to those of human design and intention?
This disneyification of nature is a great stupidity. Nature is just a series of major crises, punctuated by periods with some novelty -- that this process should be preferable to any other, reads quite implausibly to me.