Understanding the Chase to Escape the Cycle

Abstract

Even on farmland, every species exists within a complex web of interactions with other organisms. These negative and positive relationships form a system that tends to dampen dramatic changes in populations. For example, if a prey species becomes very abundant, a resident predator species will grow as a result of the increased food resource. Also, other potential predators may respond by switching from a less abundant to the more abundant prey species. In the same sense that a vacuum is quickly filled by air, whenever resources are abundant or unused, the open niche space will be quickly filled by any organism that can take advantage of the resources. Such an organism gains a ready supply of food and will increase in number as its fertility rises. Optimal conditions result in a population increase of the prey species that will trigger growth in the population of its predators. But because the predator population cannot grow until the prey species has become more abundant, the change in population size of the predator will always lag behind that of the prey species. So, during the lag phase, the prey species is not being controlled by its predators.