Chap. 6 Population Ecology (II)

1. Chap. 6 Population Ecology (II) 鄭先祐 (Ayo) 國立台南大學 環境與生態學院 2008年2月至6月

2. Population ecology • Properties of the population • Basic concepts of rate • Intrinsic rate of natural increase • Concept of carrying capacity • Population fluctuations and cyclic oscillations • Density-independent and density-dependent mechanisms of population regulation chap.6 population ecology (II)

3. Patterns of dispersion • The Allee principle of aggregation and refuging • Home range and territoriality • Metapopulation dynamics • Energy partitioning and optimization: r- and K-selection • Population genetics • Life history traits and tactics chap.6 population ecology (II)

4. 7 Patterns of Dispersion • Patterns of dispersion • Random • Regular (uniform) • Clumped • Regular clumped Fig 6-22. four basic patterns of the dispersion of individuals within a population. chap.6 population ecology (II)

5. Table 6-2 In all but 3 of 11 quadrates, spiders were randomly distributed. chap.6 population ecology (II)

6. 8 The Allee Principle of Aggregation and Refuging • Aggregation • Local habitat or landscape differences • Daily and seasonal weather changes • Reproductive processes • Social attraction • Allee principle of aggregation • undercrowding or overcrowding may be limiting chap.6 population ecology (II)

7. Fig. 6-23. Illustration of the Allee principle. • Growth and survival is greatest when the population size is small. • In an intermediate-sized population being the most favorable. • In the latter instance, undercrowding is as detrimental as overcrowding. chap.6 population ecology (II)

8. chap.6 population ecology (II)

9. Refuges • a very successful aggregation strategy has been termed refuging. • Refuges are site or situations where members of an exploited population have some favorable central place or core – for example, a starling roost or a large breeding colony of sea birds. • Lek (mating arena) (求偶競技場) • A lek is a gathering of males, of certain animal species, for the purposes of competitive mating display. chap.6 population ecology (II)

10. Relevant to human • The Allee principle is relevant to the human condition. • Aggregation into cities and urban districts (a refuging strategy) is obviously beneficial • But only up to a point, in connection with the law of diminishing returns. chap.6 population ecology (II)

11. 9 Home Range and Territoriality • Isolation usually is the result of • Competition between individuals for resources in short supply • Direct anagonism, involving behavioral responses in higher animals and chemical isolation mechanisms (antibiotics and allelopathics) in plants, microorganisms, and lower animals. • Home range vs. territory chap.6 population ecology (II)

12. Fig. 6-25. (A) home ranges of meadow voles (Microtus pennsylvanicus) in fragmented and nonfragmented habitat patches. chap.6 population ecology (II)

13. Fig. 6-25. (A) home ranges of meadow voles (Microtus pennsylvanicus) in fragmented and nonfragmented habitat patches. chap.6 population ecology (II)

14. Fig. 6-25 (B) Territories of song thrushes (Turdus philomelos) in two consecutive years. Note that individuals 1,6, and 7 maintained the same territories both years. chap.6 population ecology (II)

15. Fig. 6-25 (B) Territories of song thrushes (Turdus philomelos) in two consecutive years. Note that individuals 1,6, and 7 maintained the same territories both years. chap.6 population ecology (II)

16. Fig. 6-26. Fitness in terms of body weight gained or lost daily of territory-holding spiders compared with individuals unable to establish and hold territories (floaters). chap.6 population ecology (II)

17. 10 Metapopulation Dynamics Fig. 6-27. Hypothetical metapopulation distribution. Species may periodically disappear from low-quality patches. chap.6 population ecology (II)

18. 11 Energy Partitioning and Optimization: r- and K-Selection • Partitioning or allocation of energy • Maintenance, Growth, Reproduction • net energy • r-selection • K-selection chap.6 population ecology (II)

19. Fig. 6-28. Hypothetical allocation of energy to three major activities necessary for survival in four contrasting situation (A-D) where the relative importance of each activity varies. chap.6 population ecology (II)

20. Fig. 6-29 Optimization cost-benefit models (A) Balancing use of food sources. ∆S = energy expended in searching for a preferred food item; ∆P = energy expended in pursuing a particular food item 不分好壞食物 找較難找的食物 chap.6 population ecology (II)

21. Fig. 6-29 (B) Balancing use of foraging areas. ∆T = energy expended on traveling between catches; ∆H = energy expended on hunting chap.6 population ecology (II)

22. Fig. 6-29. Balancing time spent on reproduction and feeding. chap.6 population ecology (II)

23. Table 6-3 chap.6 population ecology (II)

24. Table 6-4 chap.6 population ecology (II)

25. Fig. 6-31. Reproductive effort plotted against nonreproductive biomass in six populations of four species of goldenrods (Solidago). chap.6 population ecology (II)

26. 12 Population Genetics • Population genetics • Natural selection • Evolution • Adaptation • refers to traits of an organism that increase its fitness to survive and reproduce. • Hardy-Weinberg equilibrium law chap.6 population ecology (II)

27. Hardy-Weinberg equilibrium law • Mating is random • New mutations do not occur • No gene flow • No natural selection • The population size is large chap.6 population ecology (II)

28. Neutral mutation Genetic drift Effective population Inbreeding Altruistic behaviors Eusociality Kin selection Inclusive fitness 12 Population Genetics chap.6 population ecology (II)

29. chap.6 population ecology (II)

30. chap.6 population ecology (II)

31. Fig. 6-35. The Florida scrub jay (Apelocoma coerulescens) chap.6 population ecology (II)

32. 13 Life History Traits and Tactics • four life history traits that are key to survival tactics • Brood size • Size of young (at birth, hatching, or germination) • Age distribution of reproductive effort • Interaction of reproductive effort with adult mortality (especially the ratio of juvenile to adult mortality) chap.6 population ecology (II)

33. Life history theories • Where adult mortality exceeds juvenile mortality, the species should reproduce only once in a lifetime, where juvenile mortality is higher, the organism should reproduce several times. • Brood size should maximize the number of young surviving to maturity averaged over the lifetime of the parent. • Ground-nesting birds, clutch size最大 • Nesting in a cavity or other protected place will have a much smaller clutch size. chap.6 population ecology (II)

34. In expanding populations, selection should minimize age at maturity (r-selected organisms); in stable populations, maturation should be delayed. • When there is risk of predation, scarcity of resources, or both, size at birth should be large; conversely, size of young should decrease with increasing availability of resources and decreasing predation or competition pressure. chap.6 population ecology (II)

35. For growing or expanding populations in general, not only is the age of maturity minimized and reproduction concentrated early in life, but also brood size should be increased and a large portion of energy flow partitioned to reproduction – a combination of traits recognizable as an re-selection tactic. For stable populations, K-selection. • When resources are not strongly limiting, breeding begins at an early age. • Complex life histories enable a species to exploit more than one habitat and niche. chap.6 population ecology (II)

36. 問題與討論 Japalura@hotmail.com Ayo 台南站： http://mail.nutn.edu.tw/~hycheng/ chap.6 population ecology (II)