1. Demography

2. Rearrange Fundamental Equation
Δ N = B – D + I – E Nfuture = Nnow + B – D + I – E Often we assume that I = E, so no net dispersal

3. Common Field Grasshopper

5. R0 – Net Reproductive Rate
If Ro = 1 – population is stable (constant)
If Ro > 1 – population is increasing
If Ro < 1 – population is decreasing

6. Red Deer – Stag, Hind, Fawn

7. Isle of Rhum, Scotland

8. Red deer fawn
being tagged
for study

11. Arithmetic scale
Logarithmic scale

12. General types of survivorship curves

13. Human management of species may change survivorship curves
A – fish mortality in
typical
population
B – fish taken
by fishing

16. Population
Pyramid
For France
Jan. 1, 1967

18. Changes in population of Japan over time

19. Changes in population of Canada from 1971-2006

21. Population Growth Models

22. R0 – Net Reproductive Rate

23. Reproductive Rates
R0 – Net Reproductive Rate – applies to populations with discrete generations and/or semelparous species
r – Intrinsic Rate of Natural Increase – is calculated from R0 and is applied to populations overlapping generations and/or iteroparous species

26. Spruce Budworm

27. Spruce Budworm
Budworm defoliation

28. Northern Elephant Seal
Reduced to about 20 by 1890’s
Model of exponential recovery predicted 80 seals by 1906; 40,960 seals by 1978
Real data – 125 seals in 1911; 60,000 seals in 1977

29. Because exponential growth is seldom seen, population growth must be constrained - two types of constraints
1) density independent constraints - growth constraints that are not effected by population size - usually abiotic - weather, storms, volcanos
2) density dependent constraints - growth constraints whose effects change as population size increases - usually biotic - competition, predation, parasitism, disease