Before reading the article "Yellowstone after Wolves," (written by Douglas W. Houston), I didn't know a whole lot about Yellowstone, only having been there once. I didn't know that wolves were re-introduced in 1995 - 1996 (D Smith, R Peterson, and D Houston, 2003), and assumed they'd always been there. After considering that fact, I figured since wolves are major predators, they would have a big impact on the population of deer, rabbits and other smaller herbivores, but didn't think there would be any other major consequences. I expected the article to support that, and give me more detail on the subject, but not give me a lot of new information. .
After reading the article, I realize my assumptions were wrong on quite a few levels. The study that was done, compares the ecosystem in Yellowstone, with the one of Isle Royale national park, which in contrast to Yellowstone, is a closed system. Isle Royale had a time period when it was a wolf-free system, but they re-introduced themselves in 1940, by crossing the frozen Lake Superior. In contrast, wolves were re-introduced to Yellowstone by men, in an attempt to naturally regulate the population of elk and moose. (D Smith, R Peterson, and D Houston, 2003). .
What I didn't realize was that an overpopulation of moose in particular, is harmful to the vegetation around. Moose live off the trees in their environment, and destroy them in the process. The repopulation of wolves in both parks has lowered moose population significantly, and in return, more trees are growing and the surrounding vegetation is starting to recover. Elk also have been very harmful to vegetation, especially aspen trees. Increased growth in aspen trees has been recorded shortly after reintroduction. (D Smith, R Peterson, and D Houston, 2003). .
The presence of wolves in Yellowstone has also influences the population of other species. The grizzly bear population in both parks has had a steep increase since wolves made their comeback.
