Download a free copy of NetLogo from the website http://ccl.northwestern.edu/ netlogo/. In...

Download a free copy of NetLogo from the website http://ccl.northwestern.edu/ netlogo/. In the “Models Library” open the model “Wolf Sheep Predation” (see the category “Biology”) and turn on the “grass?” switch. Use the model to determine why the wolf population goes to 0 fairly quickly when the grass regrowth time is set to 10 (see Fig. 13.4).

FIGURE 13.4 Population sizes as a function of time for grass regrowth time equal to 10, predator-prey model.