That lacks an important nuance: in most circumstances (regarding soil type/nitrogen deposition), not mowing at all would lead to those patches being overgrown by fast growers leading to less plant diversity. Can happen in as little as a year or 2. So the mowing itself is not the problem, it's the amount, how and when.
You really cannot talk about this in statements like they apply everywhere. Here's an example: around where I live, the number 1 activity by nature preservation groups when it comes to restoring grasslands of all kinds, is mowing. For a couple of reasons, but the main one being that nitrogen deposition fertilizes the soil too much, so it gets countered by removing biomass via mowing. Not doing that results is fast growers. Not because the'yre indicating a recovery process, just because they outgrow what was there originally. Which is the opposite of recovery.
leading to a much more healthy ecosystem than when you mow it all down to hell.
When I say "it's the amount, how and when" that implicates 'not mowing it all down to hell' is not the right way :)
Where I live the native prairie was naturally mowed by the bison roaming around, and so not mowing leads to a number of problems as the plants around here depend on that regular mowing. Various lightening strikes and the like ("Indians") caused regular fires as well, which took care of overgrowth. Mowing simulates that without the fire. (this is both good and bad - it makes for cleaner air, but those fires also put charcoal into the ground and so made the prairie net carbon negative over the long term which is something we desperately need)
Article from today, “let fallen leaves lie”
I let them lie on the rest of my 1.6 acres. And the 1 acre that's forested, we're working on trying to de-invasive-ize the forest and try to help rehabilitate it. Its just 2 of us, but we're trying.
Given the dramatic impacts we have made on a global scale, is trying to preserve de-humanified areas realistic anymore? Or are we supposed to simply try to maximize the diversity of life without regard to what life was in a place before humans arrived?
We also don't use any chemicals to do the killing, as so many of those have terrible side effects. Killing larger invasives involves something as simple as "black contractor bag enveloping and tied at base". It captures all the seeds, kills the plant, and provides easy removal.
We also see that a lot of "lawn grasses" are also pretty invasive especially to forests. So, we also try to keep the lawn encroachment from happening..... as much. Ive done the high tech solution of "lay a slab of plywood on the grasses at the edge of the forest"!
We're also designing our garden with local plants in mind, including rarer plants for our area. If/when those flower and seed, we're seeing natives with natives. And the non-natives we bring in are checked for invasiveness.
Basically, it's being low-key stewards to the land.
Are people really so detached from nature these days that the smell of wet wood puts them off? I do despair for humankind some days when I read this sort of thing.
Fortunately, on the other side ... I have the head of the groene commissie (neighbourhood gardening enthusiastc) and a beautiful tended garden. Mine is the most natural: a barely-tended jungle which gets trimmed and brushed once a year. We have hedgehogs!
We installed ~200m^2 of green roofs in the neighbourhood and there are bug hotels all over the place so we are doing relatively well. Quite a few different varieties of bees.
All this green absorbs a lot of heat, and manages rainwater which is important at 0 above sea level and 2m below the nearby canal.
In the UK, you can buy perennial meadow seed mixes from https://www.scotiaseeds.co.uk , https://wildseed.co.uk , https://www.wildflower.co.uk, and several other companies.
Elsewhere, there should be equivalents.
While this works, an alternative if you have a lawn already is to just stop cutting it every x weeks but mow once or twice a year. Mow paths where needed. More often than not there are already seeds/plants in the soil which just never got the chance to grow. And if not, depending on where you live, fauna and wind will transport seeds to your garden. The end result (mind you, takes years) will usually be similar: of the seed mixes bought, a bunch won't grow, others might but won't thrive. Whereas starting from 'scratch' this also happens. And what's left are those which happen to thrive best on the local soil type and circumstances, which usually is what works best for the local ecosystem.