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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6月
1 Types of Interaction
Between Two Species
 neutralism
 competition, direct interference type
 amensalism
( -- 0 )
 commensalism ( + 0 )
 parasitism ( + -- )
 predation ( + -- )
 protocooperation ( + + ) (not obligatory)
 mutualism ( + + ) (obligatory)
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Table
7-1
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Fig. 7-1.
coordinate
model of
two-species
interactions
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Growth equation model
dN/dt = rN – (r/K)N2 – CN2N
Growth rate = unlimited rate – selfcrowding effects – detrimental effects of
the other species
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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.
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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.
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4 Interspecific Competition
and Coexistence
Interspecific competition
Interference competition
Exploitation competition
Competitive exclusion principle
Gause principle
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Fig. 7-2.
Competition
between two
closely
related
species of
protozoa that
have similar
niches.
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Fig. 7-3. The case of
coexistence in populations
of clover (Trifolium) (紅花
草、苜蓿)
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The logistic equation
dNi/dt = riNi (1-Ni/Ki)
dNi/dt = riNi (1-Ni/Ki - aijNj/Ki)
dNj/dt = rjNj (1-Nj/Kj - ajiNi/Kj)
at equilibrium
(Ki - Ni - aijNj) / Ki = 0
(Kj - Nj - ajiNi) / Kj = 0
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(21-3)
(21-4)
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Fig. 21-4
(b) Ki - Ni - aijNj = 0
(c) Kj - Nj - ajiNi = 0
二元一次方程式
Ni 和 Nj
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Fig. 21-5 Graphic representation f the
equilibrium conditions for two species of which
species i is the better competitor.
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Fig. 21-6 The course of competition between
two populations.
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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.
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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 。
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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
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Fig. 7-4. (A) Factors that control the distribution of two
species of barnacles in an intertidal gradient.
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Fig. 7-4. (B) an example of an intertidal zone.
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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.
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Fig. 22-25
The
phenomenon
of character
displacement.
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Fig. 22-26
Proportions
of
individuals
with breaks
of different
sizes in
populations
of ground
finches on
several of
the
Galapagos
islands.
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5 Positive/Negative Interactions:
Predation, Herbivory, Parasitism,
and Alleopathy
Predation and parasitism
Hervivory
Alleopathy
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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.
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Fig. 7-6.
Evolution of
coexistence in
the hostparasite
relationship
between
house fly and
parasitic wasp
populations in
a laboratory
investigation.
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Chestnut tree and fungus
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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.
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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
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ecology
the population was harvested
per reproductive
period
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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.
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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.
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Table 7-2
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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
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The effects of agricultural tillage (犁耕) on
the mycorrhizal soil community
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螞蟻與金合歡(acacia)喬木
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Fig. 7-12.
Peritrophic
mycorrhizae
forming clusters
or asses
around the
roots of a
spruce seeding.
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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。
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Fig. 7-12 (B) Principal nitrogen fixer among the epiphytic
lichens in the forest canopy community is Lobaria oregana.
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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。
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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
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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.
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Table 7-4
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8 Biodiversity
Diversity = richness + apportionment (evenness)
Diversity
 Pattern diversity
 Genetic diversity
 Habitat diversity
Two approaches
 Dominance-diversity (relative abundance) curves
 Diversity indices
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Fig. 7-14. Latitudinal gradient in numbers of species
of (A) breeding land birds.
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Fig. 7-14. Latitudinal gradient in numbers of species
of (B) ants.
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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.
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Fig. 7-16. Diagram depicting a stream degraded by point-source raw sewage,
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7. community
ecology
illustrating decreased species chap.
diversity
and increased
population density.
Fig. 7-17. The
effect of a single
application of
the insecticide.
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Table 7-5
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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.
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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)
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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 hypothesis
Diversity-stability hypothesis
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Concern about the loss of
biodiversity
 Keystone species
 Gene resources, genetic diversity
 Diversity be affected by
1.
2.
3.
4.
Weather, insects and disease
Technology
Demand
Human preferences
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9 Paleoecology: Community
Structure in Past Ages
Paleoecology, is the study of the
relationships of ancient flora and fauna to
their environment.
The basic assumptions
The operation of ecological principles has
been 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
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The number of pollen grains of each species group
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
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10 From Populations and
Communities to Ecosystems and
Landscapes
Holistic approach vs. reductionist
approach
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Holistic approach
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Fig. 7-21.
Diagram
showing the
linkages
among oak
trees, deer,
white-footed
mice, ticks,
gypsy moths,
and humans
in
northeastern
US forests.
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Fig. 7-22. Aerial
photograph of
experimental
ponds located at
the Miami
University of Ohio
Ecology Research
Center.
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Fig. 7-24.
(A) Fall
migration
of the
eastern
populations
of the
monarch
butterfly.
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Fig. 7-24. (B)
Spring
migration of
the eastern
populations
of the
monarch
butterfly,
including the
spring
breeding
area.
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問題與討論
[email protected]
Ayo 台南站：http://mail.nutn.edu.tw/~hycheng/
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