White Bark Deforestation

The top 1/3 of a particular mountain in Yellowstone contains a large population of white bark pine trees and about twenty grizzly bears. Over about twenty years, average temperatures get significantly warmer due to pollution and climate change. As modeled by the diagram, warmer temperatures lead to an increase in the population of white bark pine infesting beetles. An increase in the beetles overwhelms the defense systems of the white bark pine trees, and they are completely wiped out from the mountain in about a decade. Once every tree on the mountain is dead, it is assumed that since there are no more trees to support the beetles, their population would be wiped out as well. This can be seen in the diagram as the beetle populations increase, the abundance of …show more content…
Although the white bark pine trees were eliminated on that specific mountaintop, a population of them survived on other mountains about fifty kilometers away. We assumed that the trees from other mountaintops would be able to repopulate the mountaintop within about ten years relying on the assumption that the seeds can travel up to thirty kilometers at a time, so it would take some time for the seeds to travel as far as they can, grow, and produce more seeds to travel to the mountaintop. This can be seen in the model because the tree population is reduced to zero after about ten years, and they finally start coming back about ten years after measures are taken to fight climate change, which occurs around thirty years. Also, as illustrated by the model, it is assumed that the beetle will return slightly after the trees return to the mountain, and they will repopulate quickly, but their population will plateau and be kept in check by cold winters. The regeneration of trees on the mountain will also have a positive impact on the population of bears as shown in the