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Mike Bithell wrote: ... at continental scale perhaps it is quite difficult for a single species to cover enough ground to really exhaust the environment ... I was took the NetLogo wolf and sheep (and grass) model and split it into two regions with barrier between them with a small hole. Often the animals would all die in one region only to be repopulated later. Presumably with more nearly isolated regions things become even more stable. Best, -ken On Wed, 18 Jul 2018 at 01:07, SIMSOC automatic digest system < [log in to unmask]> wrote: > There is 1 message totaling 38 lines in this issue. > > Topics of the day: > > 1. Interesting "Evolutionary" Finding: Uh-Oh? > > ######################################################################## > > To unsubscribe from the SIMSOC list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=SIMSOC&A=1 > > ---------------------------------------------------------------------- > > Date: Tue, 17 Jul 2018 15:27:21 +0100 > From: Mike Bithell <[log in to unmask]> > Subject: Re: Interesting "Evolutionary" Finding: Uh-Oh? > > Just to add to this discussion - the case of Rapa Nui is disputed - see > e.g. Rainbird (2002) "A message for our future? The Rapa Nui (Easter > Island) ecodisaster and Pacific island environments" - there's actually > very little convincing evidence that Rapa Nui society collapsed as a result > of environmental destruction, although the native palm tree did become > extinct sometime after or around the time at which people arrived: the > people seem to have adapted with rock-gardens to grow crops, in the absence > of being able to fish in the deep ocean. What is very clear is that the > Europeans very effectively destroyed Rapa Nui society with the 200 or so > years after they encountered it. > Edmund's model, on the other hand, seems to align well with the standard > Hardin tragedy of the commons scenario - if there is no collective pressure > on agents to not consume all resource (and they have no foresight), and > they gain a temporary benefit from locally exhausting it, then what would > prevent its destruction? Agents able to capture all resource rapidly at the > expense of others you might think would even be favoured. My experience of > small ecosystem models of this type is that they tend to be quite tricky to > get to survive in the long term, since even a relatively slow degradation > of the environmental resource can lead to its long-term collapse (and > stochastic noise + oscillations leading to extinction doesn't help) - > however, at continental scale perhaps it is quite difficult for a single > species to cover enough ground to really exhaust the environment (until > now, that is...) > > ######################################################################## > > To unsubscribe from the SIMSOC list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=SIMSOC&A=1 > > ------------------------------ > > End of SIMSOC Digest - 16 Jul 2018 to 17 Jul 2018 (#2018-132) > ************************************************************* > ######################################################################## To unsubscribe from the SIMSOC list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=SIMSOC&A=1