1. 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. BIOL 3240 Plant and Animal Ecology – Population Dynamics

2. 22 Africanized Honeybees BIOL 3240 Plant and Animal Ecology – Population Dynamics

3. 33 Collared Doves BIOL 3240 Plant and Animal Ecology – Population Dynamics

4. 44 Rapid Changes in Response to… BIOL 3240 Plant and Animal Ecology – Population Dynamics

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6. 66 Dispersal in Rivers and Streams Stream dwellers have mechanisms to allow them to maintain their stream position. – – – Tend to get washed downstream in spates. – Muller hypothesized populations maintained via… BIOL 3240 Plant and Animal Ecology – Population Dynamics

7. 77 Dispersal in Rivers and Streams BIOL 3240 Plant and Animal Ecology – Population Dynamics

8. 88 Metapopulations A __________________ is made up of a group of subpopulations living on patches of habitat connected by an exchange of individuals. – Alpine Butterfly - Roland et al. – Lesser Kestrels - Serrano and Tella. BIOL 3240 Plant and Animal Ecology – Population Dynamics

9. 99 Patterns of Survival Three main methods of estimation: – Identify individuals born at same time and keep records from birth. – Record age at death of individuals. – Calculate difference in proportion of individuals in each age class. Assumes differences from mortality. BIOL 3240 Plant and Animal Ecology – Population Dynamics

10. 10 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. – Constructed ____________________. Discovered bi-modal mortality. – <1 yr. – 9-13 yrs. BIOL 3240 Plant and Animal Ecology – Population Dynamics

11. 11 Survivorship Curves __________: Majority of mortality occurs among older individuals. – __________: Constant rate of survival throughout lifetime. – __________: High mortality among young, followed by high survivorship. – BIOL 3240 Plant and Animal Ecology – Population Dynamics

12. 12 Survivorship Curves BIOL 3240 Plant and Animal Ecology – Population Dynamics

13. 13 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 BIOL 3240 Plant and Animal Ecology – Population Dynamics

14. 14 Age Distribution BIOL 3240 Plant and Animal Ecology – Population Dynamics What can you say about this population?

15. 15 BIOL 3240 Plant and Animal Ecology – Population Dynamics

16. 16 Age Distribution Rio Grande Cottonwood populations (Populus deltoides wislizenii) are declining. – – Reproduction depends on … – Because floods are absent, there are now fewer germination areas. BIOL 3240 Plant and Animal Ecology – Population Dynamics

17. 17 Rates of Population Change ____________: Number of young born per female. _____________________: Tabulation of birth rates for females of different ages. BIOL 3240 Plant and Animal Ecology – Population Dynamics

18. 18 BIOL 3240 Plant and Animal Ecology – Population Dynamics

19. 19 Dispersal Africanized Honeybees – Honeybees (Apis melifera) evolved in Africa and Europe and have since differentiated into many locally adapted subspecies. Africanized honeybees disperse much faster than European honeybees. – Within 30 years they occupied most of South America, Mexico, and all of Central America. BIOL 3240 Plant and Animal Ecology – Population Dynamics

20. 20 Collared Doves Collared Doves, Streptopelia decaocto, spread from Turkey into Europe after 1900. – Dispersal began suddenly. Not influenced by humans. Took place in small jumps. – 45 km/yr BIOL 3240 Plant and Animal Ecology – Population Dynamics

21. 21 Estimating Rates when Generations Overlap Common Mud Turtle (K. subrubrum) – About half turtles nest each year. – 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 BIOL 3240 Plant and Animal Ecology – Population Dynamics

22. 22 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 = Σ l 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. BIOL 3240 Plant and Animal Ecology – Population Dynamics

23. 23 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. BIOL 3240 Plant and Animal Ecology – Population Dynamics

24. 24 Dispersal in Response to Changing Food Supply Holling observed numerical responses to increased prey availability. – Increased prey density led to increased density of predators. Individuals move into new areas in response to higher prey densities. BIOL 3240 Plant and Animal Ecology – Population Dynamics

25. 25 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. BIOL 3240 Plant and Animal Ecology – Population Dynamics

26. 26 Rapid Changes in Response to Climate Change Organisms began to spread northward about 16,000 years ago following retreat of glaciers and warming climate. – Evidence found in preserved pollen in lake sediments. – Movement rate 100 - 400 m/yr. BIOL 3240 Plant and Animal Ecology – Population Dynamics