Got nothing to do right now and want to learn about carrying capacity in just a few seconds? Click here to bring up the rabbits and wolves simulator. I’ve spent many hours at work playing with it, and I still haven’t gotten bored putting in new numbers and seeing how the populations play out. You can change the starting number of wolves, rabbits, and trees, and then also alter their metabolism, birthrate, and other data. Then you click “start” and watch the rabbits eat the grass, the wolves eat the rabbits, and so on until the populations get out of balance and everything crashes (which happens every time). You can pause the simulation and bring up a population graph (or watch it move in real time), which is incredibly useful if you’re learning or teaching about carrying capacity.
I haven’t been able to find a set of numbers that makes the scenario sustainable, although when doing this with kids last week in a summer camp one group created a replication of just rabbits and grass, where the wolves had died out almost immediately but the number of rabbits and their metabolism rate were just such that the forest never fully died; it would get to the brink but then with little food, the rabbit population would dip enough for the forest to regrow slightly, starting the pattern all over again ad infinitum. The kids liked making crazy scenarios, like 200 rabbits to one wolf, or even starting with no wolves, and seeing how long they could perpetuate the populations.
If anyone does find a set of starting parameters that creates a sustainable environment, please share.