Small island ecosystems/ecologies are very poor analogies for anything but small islands. They are very unique and don't reflect non island ecologies very well. It's much more interesting to look at larger ecosystems that have already undergone civilizational collapse. Italy, post center of Roman Empire is a good example for a Mediterranean ecosystem. Northern Norway is a good example of post plague geographies (top half of Norway reverted to Sami Reindeer herder for hundreds of years). The fertile crescent was overfarmed and over irrigated. Even in the area of islands, Icelanders cut down all their slow growing arctic trees, and kept on going, without creating anything that doomers would be interested in writing about, and they never even had big trees to begin with. Inuit in some areas had no trees at all, but they did just fine.
In other words, as population grows globally, each local geography/ecology will transform into something else, but each version will be different. If you, for example, are looking at a tropical ecosystem, the recovery can be incredibly fast as the jungle takes over again, but if you are looking at an overpopulated region in an arid area, you can see increasing desertification, creeping. You can see this today, in Spain, the mideast, northern Africa.
One reason I stopped reading doomer porn per se was because of the tendency to oversimplify complex scenarios, the reindeer island for example, easter island, etc. ie, cherry picking to demonstrate a point, while ignoring the real large scale changes that already have happened, but which sadly are not as dramatic or interesting. Italy was empty in large parts post collapse, then it wasn't, and now isn't. North Norway is back to normal, no particular difference visible. Other areas don't recover, or take forever to recover, arid climates that use a lot of irrigation are very prone to long lasting soil destruction, salt build up, etc. Venezuela isn't, for example.
As the globe heats, the climate will change, thus the term 'climate change, and as populations increase past carrying capacity, political stability will begin to crumble, a process already clearly visible in the mideast and North Africa, all arid regions massively over carrying capacity. The Northern American region isn't very far over carrying capacity, the Mexican region is, it just depends.
It's actually more or less known what each ecosystem will look like depending on the average temperatures globally, since global climate change has happened enough times in the past to give geological records, but not as fast as we are doing it via CO2 releases of all possible carbon based fuel sources.
http://thearchdruidreport.blogspot.com/ ... imate.html - that's not a bad overview of such historical changes.
The basic takeaway I would say is that the larger the global population of human species, the worse the damage, and the longer it will take to recover. However, barring a massive ecosystem failure, like ocean death caused by massive acidification of the water from excessive CO2 in atmosphere, the recovery times are not at all that bad, it's about 1000 years for the worst stuff, and about 10k years to get the atmosphere back to somewhat normal, and long before these time frames are reached human populations will have returned to sustainable levels, though at a massive cost, which is a massive loss of biodiversity, but even that will be ok because all the niches we have emptied and killed off by our various monocultures will I believe be fairly rapidly filled through normal evolutionary processes, so well described in Darwin's Origin of Species. As any animal or plant breeder can tell you, developing new traits does not take very long.
Re easter island, there are a few things that are clear, whether the trees got chopped down and used up, or if the palm seeds were eaten by invasive species like rats, or both, one thing you can say for certain is that when the europeans got there, the Easter islanders were not doing much fishing from boats, since the big trees were all gone.
If you think about it, 1000 years is not very long, that's only 50 generations or so, but that's also why nuclear energy should be terminated as soon as possible, those dead zones from failed plants, you can see two of them today, and those are both being maintained by functioning industrial systems, and the toxic wastes, will be totally impossible to deal with once we are unable to marshal the degree of unsustainable resource extraction we are using today in order to create these plants, and to try to deal with them when they fail.
Since it only takes a few hundred years, if that, to forge new cultures, future humans will have no trouble at all living within a sustainable yet damaged system. It's useful to read some real ethnologies to see how that works, we're actually quite flexible as a species when you remove the artificial barriers against adaptation we have constructed in our ill conceived notion that all disease, aging, etc, are problems to solve rather than selection operators to be appreciated. On the bright side, when we lift these walls, I would expect to see a very rapid evolutionary change happening to each variant / niche of human cultures. That's what they think forced the development of early humans cultures, severe stress forced rapid adaptations of a very small group of hominids, at least that what current dna research points to.
This also by the way is why I think you can largely ignore the babble about renewable energy, for the simple reason that at this juncture, only two things will help slow or change this process/outcome, reduction in absolute terms of global CO2 from carbon fuel extraction/burning/processing to almost 0, and an immediate reduction in population numbers, the first step of which requires an immediate halt of population growth. Since both of these would require an instant halt of the social systems involved around non sustainable resource extraction/exploitation, which we give cute names like capitalism or communism or democratic socialism or fascism, it's pretty obvious this best case outcome can now be totally excluded from the list of realistic scenarios, and if that's not obvious enough, all you have to do is watch global CO2 levels from the Maunu Lua observatories.
http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.htmlSince within the last few years the website
http://350.org/ that was created pre 350 ppm CO2 levels to advocate for cuts in CO2 pollution to keep levels below 350ppm, that target is already long since gone, and current levels are now around 400ppm, which is an incredibly rapid growth, despite all the babble about solar or wind this or that, and since no oil or coal is being left in the ground at this point to keep from burning it, you can safely ignore those types of green fantasies about our future.