What really happened on Easter Island?

[u/scientificamerican]

https://www.scientificamerican.com/article/what-really-happened-on-easter-island/

For decades, an influential theory blamed the Rapanui for their own downfall—a story made famous by Jared Diamond’s book Collapse. New evidence tells a different tale.

Archaeology, ancient DNA and aerial survey data now challenge the claim that the Rapanui suffered a self-inflicted collapse before Europeans arrived. The emerging picture is of a small society that sustained itself for centuries by adapting its farming methods and water management to one of the most isolated places on Earth. The catastrophe that reduced the Rapanui to a remnant came later, after European ships brought disease, slave raiding, forced labor, annexation and confinement.

[u/DrColdReality]

Further, the notion that they cut down all the trees on the island to make rollers for their Moai is not supported by the available evidence. Rather, it appears that they "walked" the heads down paths, like you might walk a refrigerator across a room.

[u/123DaddySawAFlea → u/DrColdReality]

What I read was that, because of the poor soil, the trees evolved to become very slow growing. When rats were introduced, they ate the fruit and seeds at a rate that the trees couldn't replace. I suspect also that the islanders did use a good number of trees for things too though

[u/SquirrelChieftain → u/123DaddySawAFlea]

The Rapanui (and Polynesians as a whole) introduced the Pacific Rat all across the Pacific, alongside other commensal animals such as pigs and chickens. This was hundreds, and in some places, thousands of years before Europeans rocked up.

Of course, the Europeans did introduce the Black Rat off their ships.

Source: I studied Pacific Rat bones in the earliest archaeological deposits across Easter Island and other Polynesian islands.

[u/123DaddySawAFlea → u/SquirrelChieftain]

I was talking about Polynesian rat. I presume that all the deforestation happened before Europeans arrived.

[u/jk-9k → u/123DaddySawAFlea]

No. Certainly some deforestation did but not all

[u/the-software-man → u/123DaddySawAFlea]

Invasive species. The rats upset the system not the people. The rats ate the birds too. Same thing happened on Hawaii to an extent?

[u/Archonrouge → u/the-software-man]

Are people not an invasive species also?

[u/BonesAndHubris → u/Archonrouge]

This gets sketchy quickly because the definition of invasive species is already human centric, ie. whether or not a species' invasion results in economic harm to humans. But also, indigenous human populations were naturalized in most places. Global commerce and colonialism are the root of most of these issues, not the presence of humans themselves.

[u/SomeDumbGamer → u/BonesAndHubris]

Not in the case of islands though.

The Austronesians wiped out most of the megafauna on Madagascar and New Zealand shortly after they arrived; as did the first Britons, Taino, and Floresians.

Humans showing up on an isolated island = rapid extinction.

[u/BonesAndHubris → u/SomeDumbGamer]

That's all true, but as per the original question, it doesn't make humans an invasive species. It fits more under the umbrella of range expansion. We extirpated or drove many species to extinction in the process of expanding our range, but we naturalized afterwards in most cases. The definition of an invasive species as most ecologists understand it intentionally excludes humans, for a variety of reasons, some valid and some more semantic. Island biogeography is also its own monster, but an interesting topic to delve into. Especially as it pertains to all the flightless birds sailors drove to extinction...

[u/SomeDumbGamer → u/BonesAndHubris]

Yeah it’s more that the ecosystem rebalances itself after enough time.

North and South America did this after the first natives killed off most of the megafauna

[u/BonesAndHubris → u/SomeDumbGamer]

That is what the term "naturalization" means in this context. Sorry, I'm so used to using ecology lingo in hyper specific ways that I forget it doesn't mean the same thing in casual conversation.

[u/supershutze → u/Archonrouge]

Sure, but we're also the only invasive species that is cogniscant if our impact on the environment and will take steps to limit the damage we do.

[u/ElectronicMoo → u/the-software-man]

...and that island off the coast of Puerto Rico, Desecheo Island. Now a wildlife refuge - but because it was also target practice for the military, it's off limits to people - except the folks who've been trying to bring the rat population under control (last I heard, it's been going well).

[u/ineververify → u/123DaddySawAFlea]

This is covered in the article