[sologoub]

If you try to make a planting bed in any settlement that’s more than say 100 years old on a site that was continuously lived on, you are guaranteed to come across at least some shards of glass, pots, plates, etc. Even if the spot was never explicitly a trash mound. Things break, people usually try to pick them up and put in trash, but (especially in grass) miss pieces. When kids break stuff you often don’t want them picking up sharp objects. Things get stepped on and pressed into soil. Many many reasons to find pottery shards where they seemingly don’t belong.

[pfdietz]

I was also going to say, earthworms will slowly bury objects (Darwin wrote on this), but that region didn't have earthworms at the time.

[bastawhiz]

TIL that earthworms in the American northeast are largely invasive species. That's very surprising to me

[7thaccount]

Are they problematic though? There were earthworms there before the ice age I think.

[andy99]

https://en.m.wikipedia.org/wiki/Invasive_earthworms_of_North...

Also learning about this today. Apparently they're bad for ecosystems that had evolved with slowly decaying organic matter (because they eat it all quickly). In particular forests.

At least in my education they have always been framed as a vital component of the ecosystem and a sign of healthy soil. It's interesting to learn that's not true.

[pfdietz]

To some extent it's a matter of definition, and whether being caused by humanity means it's bad. After all, the native earthworms would eventually have migrated north and caused similar changes.

Is it bad that redwoods are doing very well in the UK?

[happosai]

The problem isn't "because it was caused by humans" per se. Invasive species because of the speed they migrate. Adapting genetically changing environment is the core of life in our planet, but it takes thousands of generations. Humans spread invasive species much faster than the local fauna can adapt.

[maxerickson]

There's invasive species that are hugely problematic, converting whole forests from fungal decomposition of leaves to bacterial (changing the soil conditions quite a lot).

[mapt]

I've read this, but I'm not 100% clear on this. I think it's probably entangled with the glaciation / interglacial transition, which happened relatively recently. Earthworms are invasive in Michigan, but so are _trees_ in that timescale. It seems like having a foot thickness of forest duff decomposing slowly is probably not a very ecologically stable situation, and might be a temporary phase as the forests creep northwards and the temperatures creep up. Earthworms are not especially frost-hardy, and need to burrow deep enough to survive frost, which is physically difficult as you go farther north.

Has a drastic change occurred in the forest floors of, say, temperate Georgia?

[maxerickson]

I guess I don't care to understand your point.

The earthworms I am talking about were introduced by modern fishermen and have reduced mushroom habitat.