homework_3 - The sheep eat the same heather plants that the...

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Homework #3 WFC 10 NAME _____________________________ 1. What are the roles of humans and predators in determining the realized niche of the Vancouver marmot? When the humans clear cut the forest, it created stumps which the marmots confused with rocks. They burrowed under the trees while they were migrating instead of under rocks. The populations that burrowed under the tree stumps soon became extinct because they were not as protected as they would be with rocks. Badgers were able to dig them out of their burrows while they were hibernating. 2. In Krebs Chapter 2, there is an extended example of how red grouse populations are regulated. Sheep are mentioned as competitors with grouse for their food. Does grazing by sheep affect the niche or habitat of the grouse or both? Explain [remember the delta smelt example in lecture?]. The grazing would affect the niche of the grouse, because the “address” would remain the same, but the sheep's grazing would affect how the grouse can do it's job.
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Unformatted text preview: The sheep eat the same heather plants that the grouse eat, so when there are too many sheep, there is not enough food for the grouse. 3. Both niche and habitat change dramatically for salmon during their life cycle. Illustrate, using two different life history stages. When the salmon are breeding, they are in inland freshwater streams and rivers. They spawn and then swim back out to the river for the summer where the live in salt water and feed on ocean life. They travel back and forth between fresh and salt water. 4. Give an example of how you might use your understanding of niche and habitat to improve salmon conservation. Salmon need rocky stream beds to lay their eggs. If there is a lot of erosion near streams, silt can build up and in the streams the eggs will not survive. Erosion can be caused by clear cutting, or construction near rivers. In order to maintain the salmon's niche, these things should be avoided....
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This note was uploaded on 04/30/2008 for the course WFC 10 taught by Professor Moyle during the Spring '08 term at UC Davis.

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