AboutRichard Ochs Expertise I can answer questions regarding basic ecology (grade
school through high school). I can also answer some
college level questions as long as they aren't extremely technical.
Experience I had been a Park Ranger/Naturalist at Grand Teton National Park for 3 summers. Prior to that I was a naturalist for 4 summers at Cattus Island County Park in New Jersey. I also graduated from Rutgers University with a BS in Natural Resource Management.
Education/Credentials BS in Natural Resource Management from Rutgers University, with honors.
Awards and Honors Philip Alampi Scholar, Moorestown Rotary Scholar, Golden Key National Honor Society member.
Expert: Richard Ochs Date: 5/24/2008 Subject: ecology
Question Hi i'm not quite sure if this has to do with ecology, but i'm going to ask anyway, if you can help thats great.
In 1908, moose first arrived on Isle Royale in Lake Superior. Because of a lack of natural predators, the moose population grew expontially, drasticlly decreasing, however, in both 1930 and 1940. In 1948, timber,wolves joined themon the islandand since then the moose population has been relativelystable,with between 600 and 1000 individuals. A. using your prior knowledge of populations,carrying capacity, and predator, explain why the moose population twice decreased dramatically. B. explain why the population stabilized.
Answer Hi Mara,
Your question has everything to do with ecology. The decreases in population in 1930 and 1940 are most likely due to overcrowding of the moose. With no predators, the population could grow unchecked. That means the carrying capacity (also known as "K") of the ecosystem is what will usually limit the population. If there isn't enough suitable habitat, food, or water, these factors will limit the number of moose that could live in that area. This can be devastating to a herbivorous population in drought years or years of very heavy snow that cover forage well into the spring. Also, with overcrowding, it is much easier for disease to move through the population and kill off the moose in large numbers.
The population stabilized with predators because now they were keeping the population in check as opposed to the amount of food or habitat. This means that the island generally won't be overgrazed, and with the additional space afforded by lower populations it is more difficult for diseases to run through the moose population.
As an aside, you may hear that the wolves only take the weakest and sickest prey, but this is not true. Wolves, like any other predator, are opportunists. If a healthy deer, moose, or other prey animal comes by, wolves will not let it pass by to "wait" for a sick, infirmed prey animal. If they have a chance to choose, they will usually go for the slowest, easiest meal, but if they don't have a choice they will prey upon whatever is available. Moose have a unique advantage in their size as they get older, so it is much more difficult for a predator to take them, but wolves are team players and can wear almost any size animal down.
I hope this helps, and if you have any other questions feel free to ask.
