February 9, 2001FW 662 Midterm ExamThis exam is a take-home, open-book exercise. There are 4 questions; you must answer all ofthem, including multiple parts. You may use any reference material (class notes, assignedreading, library material, etc.). Under NO circumstances are you to discuss this exam withclassmates or any other individual. You are to work independently and you should not conferwith others. If you need clarification on a question, please see the instructor, or send email withyour question to [email protected] . This exam is to be turned in by 8:00 am Monday,12 February, at the start of class. Turn in this sheet with your written answers and a disk thatholds the spreadsheet models on which your answers are based. All questions require a writtenanswer. In addition, some questions also require you to provide a spreadsheet demonstratinghow you obtained your answer. Typed, short, concise answers will be graded more generouslythan hand-written, long, rambling responses. Your spreadsheets on a diskette for questions 1,2, and 4 will be used to verify that your answers were obtained in a logical fashion, and provideyou with partial credit in cases where you got the wrong solution, but just made a simple mistakein the spreadsheet. Identify your answer sheets and disks with your SSN only. Only put yourname (via your signature) on this sheet.By my signature below, I certify that I have not collaborated with anyone concerning anymaterial related to this examination. SSN Signature DateFW662 Midterm Exam – February 12, 2001 21. The Mexican Spotted Owl (MSO) is a threatened species under the Endangered SpeciesAct, with only limited demographic data available. Based on the existing natural historyinformation, the average number of young fledged per pair is 1.5, and adult (birds at least2-years old and older) survival rate is 0.88. For the purposes of this problem, assume thatowls begin nesting on their second birthday, i.e., when they are 2-years old. Unfortunately, no useful data exist to estimate the juvenile survival rate. a. (20 pts) What would the product of the survival for juveniles (birds in the agecategory from fledging to their first birthday and subadults (birds in the agecategory from 1 year to 2 years old) have to be to make the population have =1?8b. (5 pts) What additional information did you have to supply to make yourestimate?2. The Mexican Spotted Owl (MSO) is a threatened species under the Endangered SpeciesAct. For delisting this species, the Mexican Spotted Owl Recovery Plan requires that thepopulation be monitored for a 10-year period (i.e., 10 estimates of population size across9 intervals) with a power of 90% to detect a decline in the population of 20%. Since theplan has been written, newly acquired data have been used to estimate the temporalprocess standard deviation of to be 0.113.8a. (15 pts) Given this process standard deviation and assuming that the population iscurrently stable (i.e., = 1), what is your best guess at the probability of the MSO¯8population declining 20% over the 10-year interval?b. (5 pts) What assumptions did you make to estimate this probability, and howmight slightly different assumptions change your estimate?3. You are the Regional Environmental Contaminants Coordinator for the US Fish andWildlife Service at the Denver Regional Office. You are working on a fairlycontroversial issue regarding the evaluation of blackbird population control to protectsunflower crops in North and South Dakota. For several years, APHIS' National WildlifeResearch Center has been evaluating the merits of controlling blackbird populations toprotect sunflowers. The approach they are examining calls for lethal control using theavicide DRC-1339. Spring migrating blackbirds (red-winged, yellow-headed, andcommon grackles) congregate in large roosts in southeastern South Dakota. The generalapproach calls for killing up to 2 million red-winged blackbirds in the vicinity of theseroosts in April. It is their belief that killing 2 million birds each year over a three-yearstudy period will reduce breeding blackbirds in the Dakotas and southern Manitoba andSaskatchewan and in turn will reduce the damage that occurs to sunflowers in late Augustto mid-September. Population size of red-winged blackbirds is about 25 million.a. (10 pts) Frame this question in terms of red-winged blackbird populationdynamics. What are the questions you would ask and want answers for toevaluate this proposal?b. (10 pts) What data on population dynamics would you require before you issuedthe permit?4. The following (simulated) stock and recruitment data are provided for a sub-population ofFW662 Midterm Exam – February 12, 2001 3the endangered Sacramento River chinook salmon population in California. The stockare fish spawning in the river in year t, and the recruits are mature fish that return in 4years.Stock Recruits200 382250 590300 1151350 763400 1110450 1091500 1220550 845600 1155650 1929700 1643750 1449800 1823850 1733900 1120950 11511000 16641050 10161100 13391150 14401200 16261250 16051300 17441350 18411400 15951450 12481500 13121550 16451600 2107A. (20 pts) Estimate the parameters for a Ricker stock-recruitment curve from thesedata, and graph your predicted recruitment curve and observed data against thestock values.B. (15 pts) In recent years, the stock for this population has been hovering around1500 fish. The Coleman National Fish Hatchery will begin stocking an additional1,500,000 smolts each year to supplement the production of wild fish. Smolts areyoung salmon ready to leave the river, returning in 4 years or so as part of therecruits. Based on your results in part A, what is your evaluation of the usefulnessof stocking these smolts? Will stocking be beneficial or detrimental to thenumbers of recruits? What additional information would you like to have to makea full assessment of this issue?FW662 Midterm Exam – February 12, 2001 4February 12, 2001FW662 Midterm Exam Answers1. A. The product of survival is 0.1600. See the Midterm01.xls spreadsheet for how theproblem was set up. Something that many of you didn’t understand is that youcan set the subadult survival to 1 and just estimate with Solver the juvenilesurvival that makes = 1. This trick works because there is no reproduction by8birds on their first birthday. Another way is to set the rates equal, and then findthe value of the square root of the product. Note