ESM 211 Homework 4

ESM 211 Homework 4 - ESM 211 Homework 4 Due Friday, Mar. 14...

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ESM 211 Homework 4 Due Friday, Mar. 14 In this exercise you will analyze a matrix model of loggerhead sea turtles, which comes from the following paper (available on jstor): CROWDER, L. B., D. T. CROUSE, S. S. HEPPELL, and T. H. MARTIN. 1994. Predicting the impact of turtle excluder devices on loggerhead sea turtle populations. Ecological Applications 4:437-445. 1. We will start by analyzing the matrix as presented in the paper: The five stages are: 1. Eggs/hatchlings 2. Small juveniles 3. Large juveniles 4. Subadults 5. Adults Notice that this is a post-breeding census, so that the little bit of reproduction coming from the “subadults” represents the fraction of that class that mature to adulthood just before the breeding season. Enter the matrix into Excel Use PopTools -> Matrix Tools -> Draw Life Cycle to draw the bubble and arrow graph. This is a good way to check that you got the structure of your matrix right. It should look something like: Use PopTools -> Matrix Tools -> Finite rate of increase to find λ 1 . What does this tell you about the viability of the population? Notice that this is a dynamic calculation, so that you can change matrix elements and immediately see the new value of λ 1 . Can you reverse the population decline by completely eliminating the mortality of the egg/hatchling stage (this is what beach conservation efforts focus on)? 1 2 3 4 5
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Use PopTools -> Matrix Tools -> Matrix sensitivity to calculate the sensitivity (S) for each of the matrix elements (notice the checkbox for “calculate sensitivity of non-zero values?” – it should read “zero values” – checking that gives sensitivities for all matrix elements, including the zeros. If the zeros represent
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This note was uploaded on 08/06/2008 for the course ESM 211 taught by Professor Kendall during the Winter '08 term at UCSB.

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ESM 211 Homework 4 - ESM 211 Homework 4 Due Friday, Mar. 14...

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