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Chap. 7 Community Ecology

Chap. 7 Community Ecology

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Chap. 7 Community Ecology

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  1. Chap. 7 Community Ecology 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. 1 Types of Interaction Between Two Species • neutralism • competition, direct interference type • amensalism ( -- 0 ) • commensalism ( + 0 ) • parasitism ( + -- ) • predation ( + -- ) • protocooperation ( + + ) (not obligatory) • mutualism ( + + ) (obligatory) chap. 7. community ecology

  3. Table 7-1 chap. 7. community ecology

  4. Fig. 7-1. coordinate model of two-species interactions chap. 7. community ecology

  5. Growth equation model • dN/dt = rN – (r/K)N2 – CN2N • Growth rate = unlimited rate – self-crowding effects – detrimental effects of the other species chap. 7. community ecology

  6. 2 Coevolution • Coevolution is a type of community evolution. • Coevolution is the joint evolution of two or more noninterbreeding species that have a close ecological relationship, such as plants and herbivores, large organisms and their microorganism symbionts, or parasites and their hosts. • Through reciprocal selective pressures, the evolution of one species in the relationship depends in part on the evolution of the other. chap. 7. community ecology

  7. 3 Evolution and Cooperation: Group Selection • group selection, is defined as natural selection between groups or assemblages of organisms that are not necessarily closely liked by mutualistic associations. • Group selection leads to the maintenance of traits favorable to groups that may be selectively disadvantageous to genetic carriers within populations. chap. 7. community ecology

  8. 4 Interspecific Competition and Coexistence • Interspecific competition • Interference competition • Exploitation competition • Competitive exclusion principle • Gause principle chap. 7. community ecology

  9. Fig. 7-2. Competition between two closely related species of protozoa that have similar niches. chap. 7. community ecology

  10. Fig. 7-3. The case of coexistence in populations of clover (Trifolium) (紅花草、苜蓿) chap. 7. community ecology

  11. The logistic equation • dNi/dt = riNi (1-Ni/Ki) • dNi/dt = riNi (1-Ni/Ki - aijNj/Ki) (21-3) • dNj/dt = rjNj (1-Nj/Kj - ajiNi/Kj) (21-4) at equilibrium • (Ki - Ni - aijNj) / Ki = 0 • (Kj - Nj - ajiNi) / Kj = 0 chap. 7. community ecology

  12. Fig. 21-4(b) Ki - Ni - aijNj = 0(c) Kj - Nj - ajiNi = 0二元一次方程式Ni 和 Nj chap. 7. community ecology

  13. Fig. 21-5 Graphic representation f the equilibrium conditions for two species of which species i is the better competitor. chap. 7. community ecology

  14. Fig. 21-6 The course of competition between two populations. chap. 7. community ecology

  15. Fig. 21-7 (a) conditions for the stable coexistence of two competing species. (b) outcome of competition between two species that are both more strongly limited by interspecific competition than by intraspecific competition. The populations tend to diverge from the equilibrium point. chap. 7. community ecology

  16. 請應用Lotka-Volterra model 預測兩種相互競爭的族群, 其間競爭的最後結果。假設甲族群對乙族群的競爭系數是β; 乙族群對甲族群的競爭系數是α; 甲族群的族群數量是N1; 而其承載量是K1; 乙族群的族群數量是N2; 而其承載量是K2。起初時, 甲族群數量是50, 乙族群有90。請按下列(4與5題)的數值, 寫出甲乙族群最後的數量(N1, N2)。 • 同時必要寫出其相關的計算過程,才可得分。公式如下(參考用): • dN1/dt = r1N1 (k1 - N1 - αN2)/K1, • dN2/dt = r2N2 (k2 - N2 - βN1)/K2。 chap. 7. community ecology

  17. 計算出其結果 • (1) 若α=1.2 β=0.8 K1 =200 K2 =200, • (2) 若α=0.8 β=1.2 K1 =160 K2 =250, • (3) 若α=1.4 β=1.4 K1 =260 K2 =260, 期末考題範例 chap. 7. community ecology

  18. Fig. 7-4. (A) Factors that control the distribution of two species of barnacles in an intertidal gradient. chap. 7. community ecology

  19. Fig. 7-4. (B) an example of an intertidal zone. chap. 7. community ecology

  20. Fig. 7-5. the effect of competition on habitat distribution. When intraspecific competition dominates, the species spreads out and occupies less favorable areas, Where interspecific competition is intense, the species tends to be restricted to a narrower range, representing the optimum conditions. chap. 7. community ecology

  21. Fig. 22-25 The phenomenon of character displacement. chap. 7. community ecology

  22. Fig. 22-26 Proportions of individuals with breaks of different sizes in populations of ground finches on several of the Galapagos islands. chap. 7. community ecology

  23. 5 Positive/Negative Interactions: Predation, Herbivory, Parasitism, and Alleopathy • Predation and parasitism • Hervivory • Alleopathy chap. 7. community ecology

  24. Examples • Deer populations are often cited as examples of populations that tend to irrupt when predator pressure is reduced. • The most violent irruptions occur when a species is introduced into a new area. • Negative interactions become less negative with time if the ecosystem is sufficiently stable and spatially diverse to allow reciprocal adaptations. chap. 7. community ecology

  25. Fig. 7-6. Evolution of coexistence in the host-parasite relationship between house fly and parasitic wasp populations in a laboratory investigation. chap. 7. community ecology

  26. Chestnut tree and fungus chap. 7. community ecology

  27. Fig. 7-8. The plot on the left was sprayed with insecticide for eight years and is dominated by a dense stand of the goldenrod. Surrounding plots were left as unsprayed controls. Outbreak of the chrysomelid beetle occur every 5-15 years. chap. 7. community ecology

  28. Fig. 7-9. Biomass and yield in test populations of the guppy exploited at different rates at three different diet levels. The highest yields were obtained when about one third of the population was harvested per reproductive period chap. 7. community ecology

  29. Fig. 7-10. (A) Aerial view of aromatic shrubs Salvia leucophylla and Artemisia californica invading an annual grassland in the Santa Inez Valley of California and exhibiting biochemical inhibition. chap. 7. community ecology

  30. Close-up showing the zonation effect of volatile toxins produced by Salvia shrubs seen to the center-left of A. Between A and B is a zone 2 meters wide, bare of all herbs except for a few minute, inhibited seedlings. Between B and C is a zone of inhibited grassland. chap. 7. community ecology

  31. Table 7-2 chap. 7. community ecology

  32. 6 Positive Interactions: Commensalism, Cooperation, and Mutualism • commensalism – one population benefits • protocooperation – both benefit • mutualism – both benefit and completely dependent on each other • obligate symbiosis • Coprophagy = reingestion of feces chap. 7. community ecology

  33. The effects of agricultural tillage (犁耕) on the mycorrhizal soil community chap. 7. community ecology

  34. 螞蟻與金合歡(acacia)喬木 chap. 7. community ecology

  35. Fig. 7-12. Peritrophic mycorrhizae forming clusters or asses around the roots of a spruce seeding. chap. 7. community ecology

  36. 針葉樹與根瘤菌 • 左邊的沒有根瘤菌共生, • 右邊的有根瘤菌共生。 chap. 7. community ecology

  37. Fig. 7-12 (B) Principal nitrogen fixer among the epiphytic lichens in the forest canopy community is Lobaria oregana. chap. 7. community ecology

  38. 地衣 (lichens) • 地衣類,是藻類與真菌類共生的結果。 • 因為兩者的關係非常密切,所以被認為可視為單一物種。 chap. 7. community ecology

  39. 7 Concepts of Habitat, Ecological Niche, and Guild • Habitat • Ecological niche, fundamental niche • Spatial niche, trophic niche, • multidimensional niche • Niche breadth, niche overlap • Ecologically equivalent species • Guilds chap. 7. community ecology

  40. Fig. 7-13. Schematic representations of the niche concept. (A) Activity curves for two species along a single resource dimension illustrate the concepts of niche breadth and niche overlap. chap. 7. community ecology

  41. chap. 7. community ecology

  42. Table 7-4 chap. 7. community ecology

  43. 8 Biodiversity • Diversity = richness + apportionment (evenness) • Diversity • Pattern diversity • Genetic diversity • Habitat diversity • Two approaches • Dominance-diversity (relative abundance) curves • Diversity indices chap. 7. community ecology

  44. Fig. 7-14. Latitudinal gradient in numbers of species of (A) breeding land birds. chap. 7. community ecology

  45. Fig. 7-14. Latitudinal gradient in numbers of species of (B) ants. chap. 7. community ecology

  46. Fig. 7-15. Dominance-diversity profiles for three parallel streams in the same watershed that differ in their degree of pollution by urban domestic wastes. chap. 7. community ecology

  47. Fig. 7-16. Diagram depicting a stream degraded by point-source raw sewage, illustrating decreased species diversity and increased population density. chap. 7. community ecology

  48. Fig. 7-17. The effect of a single application of the insecticide. chap. 7. community ecology

  49. Table 7-5 chap. 7. community ecology

  50. Biodiversity and stability • The relationship between species diversity and stability is complex. • A positive relationship may be secondary and not causal, in that stable ecosystems promote high diversity but not necessarily the other way around. • Species is very much influenced by the functional relationships between trophic levels. • Moderate predation may increase diversity. chap. 7. community ecology