Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska

Life Tables for Population Modeling of Stellar Sea Lions (Scientific Journal Article) This assignment is based on the following scientific research article: Maniscalco JIVI, Springer AM, Adkison MD, Parker P. 2015. Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis. PLoS ONE. 10(10):e0140982. https:.-"’.-"’journals.olos.org/plosone/article?id=10.1371/1011rnal.pone.0 140982 Reading scientific journal articles is a bit different from other types of reading. First, you don’t necessarily read scientific articles from start to finish. Instead, you may focus on particular sections that are most relevant to what you are trying to learn from the article. In this assignment, you will be directed to particular sections of text to focus on. Second, the figures (graphs, maps, illustrations, etc.) are often as important, or even more important, than the text in terms of understanding the results of the research. In this assignment, you will be directed to examine particular figures and provided with some guidance on how to interpret them. Finally, scientific articles are written in technical language that can be intimidating to students (or even to scientists who are not specialists in that particular subfieldl). Below are some key terms that can help you understand the article for this assignment: Vital rates: a combined term for survival and reproduction rates Matrix population model: a type of model used to calculate A, the finite rate of population size change, from reproductive and mortality data; this contrasts with a life table, which tracks age- specific mortality and fecundity and calculate r, the intrinsic growth rate. Longitudinal Study: a type of study in which repeated measures of the same individuals are made over time Elasticity Analysis: provides an estimate of how population size will change with different values of vital rates Throughout the paper, you will focus on how ecologists make and use population models to predict how populations may change in the future. Read each section except the Methods— scientific methods are very technical. Pay special attention to the Figures. Keep these points in mind as you read: ‘ Scientists often create models based on their data, such as the population data for the sea lions. ‘ The model is checked against the original data—or validated—and then used to make predictions about the future. I. Read the Abstract and Introduction. Why did the scientists want to study the sea lion population? Why did they think that life tables would be useful for their study? Did they note anything that might complicate their analysis?

2. Examine Figure 2. How do females and males vary in their survival with age class? Whyr might this be important when creating a model of population growth? 3. All of the age class data between 2002 and 2013 are given in the life table presented in Table 1. These data are used to create the population growth model for the sea lions. Examine Figure 3. TWhat differences can you identify between the modeled data and the actial data the scientists collected? 4. Figure 4a shows the predicted growth rate of the population when population density" is not taken into account, while Figure 4b incorporates density dependence into the model. How does this change to the model alter the model’s predictions? 5. Examine Figure 5. In this graph, the scientists alter survival and fecundity parameters to see how )1 changes. Which of the Vital rates has the greatest impact on population growth rate? T-‘-"hich has the least? How do the scientists intend to use this information? Use the discussion to help answer this question.