1. Outline Intro to Population Ecology Estimating Patterns of Survival Survivorship Curves Age Distribution Rates of Population Change –Overlapping Generations Dispersal –In Response to Climate Change –In Response to Changing Food Supply

2. Readings Table 10.1, p. 263 Table 10.2, p. 264 Life Histories, pp. 311-319

3. Population Dynamics Fundamental Equation: N (t+1) = N (t) + B – D + I – E N (t+1) - N (t) = B – D + I – E =  N = B – D + I – E I E D B

14. Estimating Patterns of Survival Three main methods of estimation: –Cohort life table Identify individuals born at same time and keep records from birth.

15. Estimating Patterns of Survival Three main methods of estimation: –Static life table Record age at death of individuals.

16. Estimating Patterns of Survival Three main methods of estimation: –Age distribution Calculate difference in proportion of individuals in each age class. Assumes differences from mortality.

17. Cohort vs Static Life Tables

18. High Survival Among the Young Murie collected Dall Sheep skulls, Ovis dalli –Major Assumption: Proportion of skulls in each age class represented typical proportion of individuals dying at that age Reasonable given sample size of 608

19. High Survival Among the Young –Constructed survivorship curve Discovered bi-modal mortality –<1 yr –9-13 yrs

20. Survivorship Curves Type I: Majority of mortality occurs among older individuals. –Dall Sheep Type II: Constant rate of survival throughout lifetime. –American Robins Type III: High mortality among young, followed by high survivorship. –Sea Turtles

21. Survivorship Curves Plot Log 10 l x vs. X

22. Dall sheep (Ovis dalli) Life Table

23. Static life table for Dall Sheep x = age class n x = number alive d x = number dead l x = proportion surviving S 1000 = # per 1000 alive Ovis dalli dalli

24. Static life table for Dall Sheep Age class x = 0 = newborns = 100% survive Age class x = 1 only 623 in this age class = 752-129 prop surviving (l 1 ) = 623/752 = 0.828 Age class x = 2 only 509 survive = 623-114 prop surviving (l 2 ) = 509/752 = 0.677

25. Age Distribution Age distribution of a population reflects its history of survival, reproduction, and growth potential Miller published data on age distribution of white oak (Quercus alba) –Determined relationship between age and trunk diameter –Age distribution biased towards young trees. Sufficient reproduction for replacement –Stable population

26. Age Distribution

27. Rio Grande Cottonwood populations (Populus deltoides wislizenii) are declining –Old trees not being replaced –Reproduction depends on seasonal floods Prepare seed bed Keep nursery areas moist –Because floods are absent, there are now fewer germination areas

29. Dynamic Population in a Variable Climate Grant and Grant studied Galapagos Finches. –Drought in 1977 resulted in no recruitment Gap in age distribution Additional droughts in 1984 and 1985 Reproductive output driven by exceptional year in 1983 –Responsiveness of population age structure to environmental variation

31. Age Structure

32. Creation of Stable Age Distribution 3 2 1 Age 1 st Gen.2 nd Gen.3 rd Gen. Not Stable Stable 1 65 34 20% 30% 50% 10 35 55 10 35 55

33. Rates of Population Change Birth Rate: Number of young born per female Fecundity Schedule: Tabulation of birth rates for females of different ages

34. Frequency of Reproduction in Populations Time Number of offspring Discrete, non-overlapping Discrete, overlapping Continuous generation

35. Estimating Rates for an Annual Plant P. drummondii –R o = Net reproductive rate; Average number of seeds produced by an individual in a population during its lifetime –R o =Σl x m x X= Age interval in days l x = % pop. surviving to each age (x) m x = Average number seeds produced by each individual in each age category

36. Estimating Rates for an Annual Plant Because P. drummondii has non- overlapping generations, can estimate growth rate –Geometric Rate of Increase (λ): λ =N t+1 / N t N t+1 = Size of population at future time N t = Size of population at some earlier time

38. Estimating Rates when Generations Overlap Common Mud Turtle (K. subrubrum) –About half turtles nest each yr –Average generation time: T = Σ xl x m x / R o – X= Age in years –Per Capita Rate of Increase: r = ln R o / T –ln = Base natural logarithms

39. Fecundity (Fertility) Schedule

40. Life Table Calculations 0+2.95+3.06+1.52+0.26 = 7.70 7.70 Sum = 14.67

41. BIO 340 Exam 1 mean = 73%, sd = 15%