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Chap. 9 Competition

Chap. 9 Competition. 鄭先祐 生態主張者 Ayo 工作室. Part III Community Ecology. Chap. 9 Competition Chap.10 Predation Chap.11 Community structure Chap.12 Species diversity Chap.13 Succession. Chap. 9 Competition. The concept of the niche Types of competition defined

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Chap. 9 Competition

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  1. Chap. 9 Competition 鄭先祐 生態主張者 Ayo工作室

  2. Part III Community Ecology • Chap. 9 Competition • Chap.10 Predation • Chap.11 Community structure • Chap.12 Species diversity • Chap.13 Succession Ecology 2001 Chap. 9

  3. Chap. 9 Competition • The concept of the niche • Types of competition defined • Methods for obtaining evidence of competition • The relationship between intra-specific and inter-specific competition • The Effects of competition Ecology 2001 Chap. 9

  4. 資源(食物)隨時間會增長，但族群成長更加快速。資源(食物)隨時間會增長，但族群成長更加快速。 Ecology 2001 Chap. 9

  5. Ecology 2001 Chap. 9

  6. The concept of the niche(職位) • Habitat (棲息地) • Niche (ecological niche, functional niche) • The first to use the term niche was Charles Elton(1927). • The concept of Hutchinsonian niche Ecology 2001 Chap. 9

  7. Three dimensions of the niche Ecology 2001 Chap. 9

  8. Ecology 2001 Chap. 9

  9. Types of competition defined • Resource competition • preemptive competition (for space) • Exploitation competition (使用權) • Interference competition (干擾權) • Diffuse competition (多種影響) • Interspecific and intraspecific competition Ecology 2001 Chap. 9

  10. Methods for obtaining evidence of competition • Experimentation • A classic example was performed by J. H. Connell (1961) in his study of two species of barnacles that inhabit the rocky intertidal zone off Scotland.(Fig. 9-5, 9-6, 9-7) • Observation and inference • Diamond (1975) noted that some closely related species of birds have a “checkerboard” distribution pattern. (Fig. 9-8) Ecology 2001 Chap. 9

  11. Ecology 2001 Chap. 9

  12. Ecology 2001 Chap. 9

  13. Ecology 2001 Chap. 9

  14. Ecology 2001 Chap. 9

  15. Ecology 2001 Chap. 9

  16. Observation and inference Ecology 2001 Chap. 9

  17. 現象與推論 • The mainland has snowshoe hares in taiga habitats and arctic hares in the tundra (Fig. 9.9). • Both habitats in Newfoundland island were occupied by arctic hares, the only species on the island. • When the snowshoe hare was introduced to the island, arctic hares were soon found only in tundra habitats. • 推論：因為競爭，迫使arctic hares 讓出 taiga habitats給snowshoe hare。 Ecology 2001 Chap. 9

  18. 結果發現這是錯誤的推論！ • A predator, the lynx, plays a critical role. • When the snowshoe hare was introduced to Newfoundland, lynx numbers increased because of the greater abundance of prey. • The arctic hare is far more vulnerable to predation in taiga than is the snowshoe hare. • 結果：這是因為掠食者的壓力，而不是因為來自種間的競爭。 Ecology 2001 Chap. 9

  19. Intra-specific and inter-specific competition • In plants, a phenomenon known as self-thinning attests to the importance of intra-specific competition. • The rye grass Lolium perenne, exemplifies this phenomenon.(Fig. 9.10) • The straight line associated with the decline in density over time has a slope of –3/2. • This slope is found in many plant self-thinning lines (Fig. 9.11) Ecology 2001 Chap. 9

  20. Fig. 9.10 Self-thinning in the rye grass. Ecology 2001 Chap. 9

  21. Fig. 9.11 Regression lines from self-thinning curves for 31 stands of different species of plants. Ecology 2001 Chap. 9

  22. Replacement series 實驗 • 128 seeds of the two species were planted in each pot. • But the relative numbers of seeds of the two species varied in the series of pots. • At one extreme, all 128 seeds were A. fatua; at the other extreme, all 128 seeds were A. barbata. • Other pots were shown with 16 fatua and 112 barbata, 32 fatua and 96 barbata, and so forth. Ecology 2001 Chap. 9

  23. Intra- vs. inter-specific • Approximately 75% of all seedlings survive under pure stands of each species. (pure intra-specific competition) • If intra- and inter-specific competition were equivalent, we would expect 75% of the seedlings to survive. • What they found? (Fig. 9.12) Ecology 2001 Chap. 9

  24. Fig. 9.12 Results of replacement series competition experiments in Avena barbata and A. fatua(a) survival of seedlings.The dotted lines represent the expected result based on pure intra-specific competition.The solid lines and data points represent the actual performance in competition. Ecology 2001 Chap. 9

  25. Fig. 9.12 Results of replacement series competition experiments in Avena barbata and A. fatua(b) seed production. The dotted lines represent the expected result based on pure intra-specific competition. The solid lines and data points represent the actual performance in competition. Ecology 2001 Chap. 9

  26. The effects of competition • The long-term effect, known as character displacement, operates on an evolutionary time scale – that is, over many generations. • The short-term effect, called competitive exclusion, occurs in ecological time – that is, within a single or a few generations. Ecology 2001 Chap. 9

  27. Character Displacement • 相近的物種，於重疊分布的區域，其間的差異會因為競爭而擴大。 • 這是否普遍存在？ Ecology 2001 Chap. 9

  28. Fig. 22-25 The phenomenon of character displacement.  Ecology 2001 Chap. 9

  29. Fig. 9.13 The process of character displacement(a) individuals of one species that use resources in regions that do not overlap with the other species have a selective advantage. Ecology 2001 Chap. 9

  30. Fig. 9.13 The process of character displacement(b) over time, selection will separate the niches of the two species. Ecology 2001 Chap. 9

  31. Fig. 9.14 Head-body lengths of male weasels as a function of latitude. Ecology 2001 Chap. 9

  32. Fig. 9.15 The coefficient of variation (CV) in mandible length in Veromessor pergandei as a function of the number of granivorous ants in the community. Ecology 2001 Chap. 9

  33. Fig. 9.16a Frequency distributions of mandible sizes at different sites. The mean mandible lengths of the most similar competitors of Veromessor pergandei are indicated by the arrows. Ecology 2001 Chap. 9

  34. Fig. 9.16b Frequency distributions of mandible sizes at different sites. The mean mandible lengths of the most similar competitors of Veromessor pergandei are indicated by the arrows. Ecology 2001 Chap. 9

  35. Fig. 9.16d Frequency distributions of mandible sizes at different sites. The mean mandible lengths of the most similar competitors of Veromessor pergandei are indicated by the arrows. Ecology 2001 Chap. 9

  36. Fig. 9.16e Frequency distributions of mandible sizes at different sites. The mean mandible lengths of the most similar competitors of Veromessor pergandei are indicated by the arrows. Ecology 2001 Chap. 9

  37. Fig. 9.16f Frequency distributions of mandible sizes at different sites. The mean mandible lengths of the most similar competitors of Veromessor pergandei are indicated by the arrows. Ecology 2001 Chap. 9

  38.  Fig. 22-26 Proportions of individuals with breaks of different sizes in populations of ground finches on several of the Galapagos islands. Ecology 2001 Chap. 9

  39. Fig. 1 The considerable difference in beak morphology between these three species of Darwin's finches, Geospiza, which coexist on many Galapagos islands, has been the subject of much debate concerning its cause. Ecology 2001 Chap. 9

  40. Fig. 2 The beak morphology of Geospiza conirostris shows significant variation on different species on different islands. Ecology 2001 Chap. 9

  41. Fig. 3. The average beak depths of four species of Darwin's finches on three islands where they coexist show considerable variation from island to islands, even though the same set of possible competition occurs on each island. Ecology 2001 Chap. 9

  42. 範例：filareeTwo species of annual plants • Erodium cicutarium和E. obtusiplicatum • 運用replacement series 方法。 分成三類： • 1. Sympatric populations. • 2. Allopatric populations. • 3. Transposed populations. Ecology 2001 Chap. 9

  43. Fig. 9.17 The experimental design to examine the evolution of competitive interactions. Ecology 2001 Chap. 9

  44. Fig. 9.18 Total seed production at different levels of intra- and interspecific competition for populations of two species of Erodium. Ecology 2001 Chap. 9

  45. Competitive exclusion • Gause’s law：the competitive exclusion principle Fig. 9.19 Growth curves for Paramecium aurelia and P. caudatum in separate and mixed cultures. Ecology 2001 Chap. 9

  46. Fig. 9.20 The skulls of the saber-toothed cat Smilodoncalifornicus, a placental mammal, and the marsupial cat Thylacosmilus. Ecology 2001 Chap. 9

  47. Environmental application Introduced species: Potentially devastating competitors Zebra mussels were released into North America from the ballast of ships from Asia and Europe. Ecology 2001 Chap. 9

  48. Major invasions to Australia • The European rabbit was imported from Great Britain and soon reached such numbers that it destroyed immense tracts of rangeland. • Estimates made in the 1950s put the population at over 1 billion rabbits. Ecology 2001 Chap. 9

  49. Why do these introduced species cause such problem? • Two factors probably account for the more intractable exotics: • (1) the species’s ability to colonize new habitats • (2) its ability to out-compete native biota. Ecology 2001 Chap. 9

  50. 範例：freshwater fishes in California • 48 of 137 species of freshwater fish are nonnative. • Of these 48 introduced species, only 6 are found in undisturbed or pristine waters, and 4 of those are species of trout or salmon introduced into fishless lakes in the high Sierra. • Of the 26 species of exotics for which data exist, 24 are known to have a negative impact on native fish. Ecology 2001 Chap. 9

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