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...

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

chap. 7. community ecology 2

1 Types of Interaction Between Two Species

neutralism competition, direct interference type amensalism ( -- 0 ) commensalism ( + 0 ) parasitism ( + -- ) predation ( + -- ) protocooperation ( + + ) (not obligatory) mutualism ( + + ) (obligatory)


Table 7-1


Fig. 7-1. coordinate model of two-species interactions


Growth equation model

dN/dt = rN – (r/K)N2 – CN2N

Growth rate = unlimited rate – self-crowding effects – detrimental effects of the other species


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.


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.


4 Interspecific Competition and Coexistence

Interspecific competitionInterference competitionExploitation competition

Competitive exclusion principleGause principle


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


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


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


Fig. 21-4

(b) Ki - Ni - aijNj = 0

(c) Kj - Nj - ajiNi = 0

二元一次方程式Ni 和 Nj


Fig. 21-5 Graphic representation f the equilibrium conditions for two species of which

species i is the better competitor.


Fig. 21-6 The course of competition between two populations.


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.


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Ｎ 1; 而其承載量是Ｋ 1; 乙族群的族群數量是Ｎ 2; 而其承載量是Ｋ 2 。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 ( Ｎ 1, Ｎ 2) 。

※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 。


計算出其結果

(1) 若 α=1.2 β=0.8 Ｋ 1 =200 Ｋ 2 =200,

(2) 若 α=0.8 β=1.2 Ｋ 1 =160 Ｋ 2 =250,

(3) 若 α=1.4 β=1.4 Ｋ 1 =260 Ｋ 2 =260,

期末考題範例


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


Fig. 7-4. (B) an example of an intertidal zone.


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.


Fig. 22-25 The phenomenon of character displacement.


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


5 Positive/Negative Interactions: Predation, Herbivory, Parasitism,

and Alleopathy

Predation and parasitismHervivoryAlleopathy


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.


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


Chestnut tree and fungus


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.


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


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.


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.


Table 7-2


6 Positive Interactions: Commensalism, Cooperation, and Mutuali

sm

commensalism – one population benefits protocooperation – both benefit mutualism – both benefit and completely

dependent on each other obligate symbiosis

Coprophagy = reingestion of feces


The effects of agricultural tillage ( 犁耕 ) on the mycorrhizal soil community


螞蟻與金合歡 (acacia) 喬木


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


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。


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


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。


7 Concepts of Habitat, Ecological Niche, and Guild

HabitatEcological niche, fundamental niche

Spatial niche, trophic niche, multidimensional nicheNiche breadth, niche overlap

Ecologically equivalent speciesGuilds


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.


Table 7-4


8 Biodiversity

Diversity = richness + apportionment (evenness)Diversity

Pattern diversity Genetic diversity Habitat diversity

Two approaches Dominance-diversity (relative abundance) curves Diversity indices


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


Fig. 7-14. Latitudinal gradient in numbers of species of (B) ants.


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


Fig. 7-17. The effect of a single application of the insecticide.


Table 7-5


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.


Pattern diversity

Stratification patterns (vertical layering)Zonation patterns (horizontal segregation)Activity patterns (periodicity)Food web patterns (network organization)Reproductive patterns (parent-offspring)Social patterns (flocks and herds)Coactive patterns (resulting from competition,

antibiosis, or mutualism)Stochastic patterns (resulting from random

forces)


Biodiversity and productivity

In low-nutrient natural environments, an increase in biodiversity seems to enhance productivity.In high-nutrient or enriched environments, an

increase in productivity increases dominance and reduces diversity.

Hypothesis Diversity-productivity hypothesisDiversity-stability hypothesis


Concern about the loss of biodiversity

Keystone species Gene resources, genetic diversity Diversity be affected by

1. Weather, insects and disease

2. Technology

3. Demand

4. Human preferences


9 Paleoecology: Community Structure in Past Ages

Paleoecology, is the study of the relationships of ancient flora and fauna to their environment.

The basic assumptionsThe operation of ecological principles has bee

n essentially the same throughout various geological periods

The ecology of fossils may be inferred from what is known about equivalent or related species now living


Fig. 7-19. Fossil pollen profiles from dated layers in lake sediment cores from southern New England.

Estimated rate of pollen deposition for each plant

The number of pollen grains of each species group


10 From Populations and Communities to Ecosystems and Landscapes

Holistic approach vs. reductionist approach


Holistic approach


Fig. 7-21. Diagram showing the linkages among oak trees, deer, white-footed mice, ticks, gypsy moths, and humans in northeastern US forests.


Fig. 7-22. Aerial photograph of experimental ponds located at the Miami University of Ohio Ecology Research Center.


Fig. 7-24. (A) Fall migration of the eastern populations of the monarch butterfly.


Fig. 7-24. (B) Spring migration of the eastern populations of the monarch butterfly, including the spring breeding area.


http://mail.nutn.edu.tw/~hycheng/

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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...

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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...