Oh Deer! How Does Destroying Habitat Affect the Population of Deer and Wolves?

Canalino School
Teacher:  Vicki Walton
Scientists: Dr. Carrie Kappel and Dr. Francisco Madriñán

Hypothesis: Destroying habitat will make the population of deer and wolves decline.

Materials and methods:
We ran a simulation game to investigate the population dynamics of deer and their predators, wolves, in the face of habitat destruction by humans. Two students acted as scientists and collected data. Two students acted as the wolves and the remaining 18 students were deer. Patches of habitat were created on the playing field using circles of chairs. Each chair represented the resources needed to keep one deer alive and safe from predation. The game began with the deer out in the open, away from the habitat patches. The wolves were released to try to catch one deer each. Wolves that caught a deer survived to the next round. Deer that were caught "died" and sat on the sidelines. Deer that avoided predation and made it to a chair in one of the habitat patches survived. Every three rounds, another wolf was added to the wolf population for each wolf who had successfully caught prey three times in a row (from the "dead deer" on the sidelines). And every three rounds, another deer was added to each patch of habitat that had 4 or more deer living in it. The game ended when either the wolf or deer population crashed to zero. The game was replayed two more times to simulate the effects of habitat destruction. Each of these times, chairs were removed from some of the patches making them smaller and decreasing the chance that the deer would find safe shelter.

Results:
We observed the wolves hanging out near the biggest patches of habitat, trying to catch the deer. And we saw that the deer sought out either the closest or the largest habitat patches when trying to escape the wolves. We found that the wolf population crashed before the deer each time. With habitat destruction, the numbers of deer and wolves declined more quickly. The more habitat was lost, the quicker the populations crashed.

Conclusions:
Habitat destruction by humans affects both the deer, who depend directly on the habitat, and their predators.