chap.6 interspecific competition 鄭先祐 (ayo) 國立臺南大學 環境與生態學院...
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Chap.6 Interspecific Chap.6 Interspecific competitioncompetition
鄭先祐 鄭先祐 (Ayo)(Ayo)
國立臺南大學 環境與生態學院國立臺南大學 環境與生態學院生物科技學系 生態學 生物科技學系 生態學 (2008)(2008)
Essentials of Ecology 3rd. Ed.
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Interspecific competitionInterspecific competition
6.1 introduction6.1 introduction6.2 Ecological effects of interspecific 6.2 Ecological effects of interspecific
competitioncompetition6.3 evolutionary effects of interspecific 6.3 evolutionary effects of interspecific
competitioncompetition6.4 interspecific competition and 6.4 interspecific competition and
community structurecommunity structure6.5 how significant is interspecific 6.5 how significant is interspecific
competition in practice?competition in practice?
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Interspecific competitionInterspecific competition
6.1 Introduction6.1 Introduction Intraspecific competitionIntraspecific competition Interspecific competitionInterspecific competitionThe ecological and the evolutionary effects of The ecological and the evolutionary effects of
interspecific competitioninterspecific competition6.2 ecological effects6.2 ecological effects6.3 evolutionary effects6.3 evolutionary effects6.4 community structure6.4 community structure6.5 significant6.5 significant
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6.2 ecological effects6.2 ecological effects
6.2.1 Competition between diatoms for 6.2.1 Competition between diatoms for silicate (Fig. 6.1) silicate (Fig. 6.1)
55Fig. 6.1 competition between diatoms.Fig. 6.1 competition between diatoms.
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6.2.2 coexistence and exclusion of 6.2.2 coexistence and exclusion of competing salmonid fishes (Fig. competing salmonid fishes (Fig.
6.2)6.2)
(a) frequency of aggressive encounters (a) frequency of aggressive encounters
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(b) foraging frequency(b) foraging frequency
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(c) specific growth rate in length. Different letters indicate (c) specific growth rate in length. Different letters indicate means are significantly different from each other.means are significantly different from each other.
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6.2.3 some general observations6.2.3 some general observations
Fundamental niche is the combination of Fundamental niche is the combination of conditions and resources that allow that conditions and resources that allow that species to exist, grow and reproduce when species to exist, grow and reproduce when considered in isolation from any other considered in isolation from any other species that might be harmful to its species that might be harmful to its existence.existence.
Realized nicheRealized niche
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6.2.4 coexistence of competing 6.2.4 coexistence of competing diatoms (Fig. 6.3)diatoms (Fig. 6.3)
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6.2.5 coexistence of competing birds6.2.5 coexistence of competing birds
Percentage difference in feeding rates. Where the other Percentage difference in feeding rates. Where the other species had been experimentally removed.species had been experimentally removed.
During incubating (inc)During incubating (inc) During nestling period (nstl)During nestling period (nstl)
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6.2.6 coexistence of competing 6.2.6 coexistence of competing rodents and ants (Fig. 6.5)rodents and ants (Fig. 6.5)
The diets of ants The diets of ants and rodents and rodents overlap: sizes of overlap: sizes of seeds harvested seeds harvested by coexisting by coexisting ants and rodents ants and rodents near Portal, near Portal, Arizona.Arizona.
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6.2.7 the competitive exclusion 6.2.7 the competitive exclusion principle (Gause’s principle)principle (Gause’s principle)
If two competing species coexist in a If two competing species coexist in a stable environment, then they do so as a stable environment, then they do so as a result of niche differentiation, i.e. result of niche differentiation, i.e. differentiation of their realized niches.differentiation of their realized niches.
If, however, there is no such If, however, there is no such differentiation, or if it is precluded by the differentiation, or if it is precluded by the habitat, then one competing species will habitat, then one competing species will eliminate or exclude the other. eliminate or exclude the other.
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6.1 Quantitative aspects6.1 Quantitative aspects
The Lotka-Volterra model of intersecific The Lotka-Volterra model of intersecific competitioncompetition
dN/dt = rN(K-N)/KdN/dt = rN(K-N)/KdNdN11/d/dtt = r = r11NN11 (K (K11-N-N11 – a – a1212NN22)/K)/K11
dNdN22/d/dtt = r = r22NN22 (K (K22-N-N22 – a – a2121NN11)/K)/K22
KK11-N-N11 – a – a1212NN2 2 = 0= 0KK22-N-N22 – a – a2121NN1 1 = 0= 0
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KK11-N-N11 – a – a1212NN2 2 = 0= 0KK22-N-N22 – a – a2121NN1 1 = 0= 0
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Fig. 6.7 the outcomes of competition generated by Fig. 6.7 the outcomes of competition generated by the Lotka-Volterra competition equations for the the Lotka-Volterra competition equations for the
four possible arrangement of the N1 and N2.four possible arrangement of the N1 and N2.
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Fig. 6.8 On shores in which gaps are not created, Fig. 6.8 On shores in which gaps are not created, mussels are able to exclude the brown alga mussels are able to exclude the brown alga PosteisiaPosteisia, but , but where gaps are created regularly enough the two species where gaps are created regularly enough the two species coexist, even though coexist, even though PostelsiaPostelsia is eventually excluded by is eventually excluded by the mussels from each gap.the mussels from each gap.
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6.3 Evolutionary effects of 6.3 Evolutionary effects of interspecific competitioninterspecific competition
Evolutionary avoidance of competitionEvolutionary avoidance of competition Invoking the ghost of competition pastInvoking the ghost of competition past The difficulty of distinguishing ecological and The difficulty of distinguishing ecological and
evolutionary effectsevolutionary effects 6.3.1 character displacement and ecological 6.3.1 character displacement and ecological
release in the Indian mongooserelease in the Indian mongoose 6.3.2 character displacement in Canadian 6.3.2 character displacement in Canadian
sticklebackssticklebacks 6.3.3 Evolution in action: niche-differentiated 6.3.3 Evolution in action: niche-differentiated
bacteriabacteria
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6.3.1 the Indian mongoose (6.3.1 the Indian mongoose ( 貓鼬貓鼬 ) )
Fig. 6.11 (a) Fig. 6.11 (a) Native Native geographic range geographic range of of Herpester Herpester JavanicusJavanicus (j), (j),
H. edwardsiiH. edwardsii (e), (e), and and
H. smithiiH. smithii (s). (s).
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Compared to area VII (H. j. alone), animals in areas Compared to area VII (H. j. alone), animals in areas III, V and VI, where they compete with the two larger III, V and VI, where they compete with the two larger species, are smaller. On the islands, they have species, are smaller. On the islands, they have increased in size since their introduction, but are still increased in size since their introduction, but are still not as large as in area VII.not as large as in area VII.
(b) Maximum (b) Maximum diameter (mm) of diameter (mm) of the upper canine the upper canine (CL) for (CL) for Herpestes Herpestes javanicus(javanicus( 貓鼬貓鼬 )) Symbols in blue Symbols in blue represent mean represent mean female size and in female size and in maroon mean male maroon mean male size.size.
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Character DisplacementCharacter Displacement
相近的物種，於重疊分布的區域，其間相近的物種，於重疊分布的區域，其間的差異會因為競爭而擴大。的差異會因為競爭而擴大。
這是否普遍存在？這是否普遍存在？
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Fig. 1 The considerable difference in beak Fig. 1 The considerable difference in beak morphology between these three species of morphology between these three species of Darwin's finches, Darwin's finches, GeospizaGeospiza, which coexist on , which coexist on many Galapagos islands, has been the many Galapagos islands, has been the subject of much debate concerning its cause.subject of much debate concerning its cause.
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Fig. 2 The beak morphology of Fig. 2 The beak morphology of Geospiza Geospiza conirostrisconirostris shows significant variation on shows significant variation on different species on different islands.different species on different islands.
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Fig. 3. The average beak depths of four species Fig. 3. The average beak depths of four species of Darwin's finches on three islands where they of Darwin's finches on three islands where they coexist show considerable variation from island coexist show considerable variation from island to islands, even though the same set of possible to islands, even though the same set of possible
competition occurs on each island.competition occurs on each island.
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6.3.2 character displacement in 6.3.2 character displacement in Canadian sticklebacks (Canadian sticklebacks ( 刺魚刺魚 ) )
Brook sticklebacksBrook sticklebacksNinespine sticklebacksNinespine sticklebacks In sympatry, the brook In sympatry, the brook
sticklebacks possess sticklebacks possess significantly shorter gill significantly shorter gill rakers (more suited for rakers (more suited for foraging in open water), foraging in open water), longer jaws and deeper longer jaws and deeper bodies.bodies.
• Pre-displacement phenotypes
• Post-displacement phenotypes.
Gill rakers are bony, finger-like projections of the gill arch filaments which function in filter-feeders in retaining food organisms.
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Fig. 6.12 Means of group median growth for Fig. 6.12 Means of group median growth for sympatric brook sticklebacks, representing post-sympatric brook sticklebacks, representing post-displacement phenotype (maroon bar) and brook displacement phenotype (maroon bar) and brook sticklebacks living alone, representing pre-sticklebacks living alone, representing pre-displacement phenotypes (blue bar)displacement phenotypes (blue bar)
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6.3.3 evolution in action: niche-6.3.3 evolution in action: niche-differentiated bacteriadifferentiated bacteria
Three types of the same bacterial species, Three types of the same bacterial species, Pseudomonas fluorescensPseudomonas fluorescens..Smooth (SM), wrinkly spreader (WS), and Smooth (SM), wrinkly spreader (WS), and
fuzzy spreader (FS) (Fig. 6.13)fuzzy spreader (FS) (Fig. 6.13)
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Fig. 6.12 (b) in shaken sulture vessels, pure SM Fig. 6.12 (b) in shaken sulture vessels, pure SM cultures are maintainedcultures are maintained
(c) But in unshaken, initially pure SM cultures, (c) But in unshaken, initially pure SM cultures, WS and FS mutants arise.WS and FS mutants arise.
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6.4 interspecific competition and 6.4 interspecific competition and community structurecommunity structure
6.4.1 Limiting resources and the regulation of 6.4.1 Limiting resources and the regulation of diversity in phytoplankton communitiesdiversity in phytoplankton communities
6.4.2 Niche complementarity amongst anemone 6.4.2 Niche complementarity amongst anemone (( 海葵海葵 ) fish in Papua New Guinea) fish in Papua New Guinea
6.4.3 Species separated in space or in time6.4.3 Species separated in space or in time 6.4.4 Spatial separation in trees and tree-root 6.4.4 Spatial separation in trees and tree-root
fungifungi 6.4.5 Temporal separation in mantids (6.4.5 Temporal separation in mantids ( 螳螂螳螂 ) )
and tundra plantsand tundra plants
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6.4.1 Limiting resources and the regulation 6.4.1 Limiting resources and the regulation of diversity in phytoplankton communitiesof diversity in phytoplankton communities
The principal limiting resources for The principal limiting resources for phytoplankton growth are nitrogen, phytoplankton growth are nitrogen, phosphorus, silicon and light.phosphorus, silicon and light.
The spatial and temporal patterns in The spatial and temporal patterns in phytoplankton diversity in the three lakes phytoplankton diversity in the three lakes for 1996 and 1997 are shown in Fig. for 1996 and 1997 are shown in Fig. 6.14a.6.14a.
Diversity clearly increases with the number Diversity clearly increases with the number of limiting resources. (Fig. 6..14b)of limiting resources. (Fig. 6..14b)
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Fig. 6.14a. Variation in phytoplankton species diversity Fig. 6.14a. Variation in phytoplankton species diversity (Simpson’s index) with depth in 2 years in three large (Simpson’s index) with depth in 2 years in three large lakes.lakes.
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Fig. 6.14b. Phytoplankton diversity associated Fig. 6.14b. Phytoplankton diversity associated with samples with different numbers of with samples with different numbers of measured limiting resources.measured limiting resources.
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6.4.2 Niche complementarity 6.4.2 Niche complementarity amongst anemone fish (amongst anemone fish ( 海葵魚海葵魚 ))
Fig. 6.15 (a) Map Fig. 6.15 (a) Map showing the location of showing the location of three replicate study three replicate study sites in each of four sites in each of four zones within and zones within and outside Madang outside Madang Lagoon.Lagoon.
N, nearshore; N, nearshore; M, mid-lagoon; M, mid-lagoon; O, outer barrier reef;O, outer barrier reef; OS, offshore reefOS, offshore reef
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Fig. 6.15b. The percentage of three common Fig. 6.15b. The percentage of three common species of anemone (species of anemone (H. magnifica, H. crispa and H. magnifica, H. crispa and S. mertensiiS. mertensii) occupied by different anemone fish ) occupied by different anemone fish species (species (AmphiprionAmphiprion spp.) spp.)
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6.4.4 Spatial separation in trees 6.4.4 Spatial separation in trees and tree-root fungiand tree-root fungi
Trees vary in their capacity to use resources Trees vary in their capacity to use resources such as light, water and nutrients.such as light, water and nutrients.
A study in Borneo of 11 tree species in the A study in Borneo of 11 tree species in the genus genus MacarangaMacaranga showed marked differentiation showed marked differentiation in light requirements, from extremely light-in light requirements, from extremely light-demanding species to shade-tolerant species. demanding species to shade-tolerant species. (Fig. 6.16a)(Fig. 6.16a)
The Macaranga species were also differentiated The Macaranga species were also differentiated along a second niche gradient, with some along a second niche gradient, with some species being more common on clay-rich soils species being more common on clay-rich soils and others on sand-rich soils (Fig. 6.16b)and others on sand-rich soils (Fig. 6.16b)
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大戟科大戟科 (Euphorbiaceae)(Euphorbiaceae)血桐血桐 ((MacarangaMacaranga tanarius) tanarius)
Fig. 6.16a. Fig. 6.16a. Percentage of Percentage of individuals in each individuals in each of five crown of five crown illumination classes illumination classes for 11 for 11 MacarangaMacaranga species.species.
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Fig. 6.16b. Three dimensional distribution of the Fig. 6.16b. Three dimensional distribution of the 11 species with respect to maximum height, the 11 species with respect to maximum height, the proportion of stems in high light levels and proportion of stems in high light levels and proportion of stems in sand-rich soils.proportion of stems in sand-rich soils.
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Fig. 6.17 the vertical Fig. 6.17 the vertical distribution of 26 distribution of 26 ectomycorrhizal fungal ectomycorrhizal fungal (( 真菌真菌 ) species in the ) species in the floor of a pine forest floor of a pine forest determined by DNA determined by DNA analysis.analysis.
Litter layerLitter layer F layer, fermentation F layer, fermentation
layerlayer H layer, a thin humified H layer, a thin humified
layer, layer, B horizon, mineral soil B horizon, mineral soil
beneathbeneath
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6.4.5 Temporal separation in 6.4.5 Temporal separation in mantids(mantids( 螳螂螳螂 ) and tundra plants) and tundra plants
Two species ofTwo species of mantids mantids commonly coexist commonly coexist both in Asia and North America.both in Asia and North America.
Tenodera sinensisTenodera sinensis and and Mantis religiosaMantis religiosa have life cycles that are 2-3 weeks out of have life cycles that are 2-3 weeks out of phase.phase.
T. sinensisT. sinensis, which normally hatches , which normally hatches earlier, was unaffected by M. religiosa.earlier, was unaffected by M. religiosa.
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To trace how tundra species differed in uptake of To trace how tundra species differed in uptake of different nitrogen sources, McKane et al. (2002) different nitrogen sources, McKane et al. (2002) injected three chemical forms labeled with the injected three chemical forms labeled with the rare isotope rare isotope 1515N (ammonium, nitrate and glycine) N (ammonium, nitrate and glycine) at two soil depth (3 and 8 cm) on two occation at two soil depth (3 and 8 cm) on two occation (June 24 and August 7). (June 24 and August 7).
Concentration of the Concentration of the 1515N tracer was measured in N tracer was measured in each of five common tundra plants 7 days after each of five common tundra plants 7 days after application. (Fig. 6.18)application. (Fig. 6.18)
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Fig. 6.18a mean uptake of available soil nitrogen in terms Fig. 6.18a mean uptake of available soil nitrogen in terms
of chemical form of chemical form by the five most common species.by the five most common species.
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Fig. 6.18bFig. 6.18b mean uptake of available soil nitrogen in terms of mean uptake of available soil nitrogen in terms of
timing of uptake timing of uptake by the five most common species.by the five most common species.
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Fig. 6.18cFig. 6.18c mean uptake of available soil nitrogen mean uptake of available soil nitrogen in terms of depth of uptake by the five most in terms of depth of uptake by the five most common species.common species.
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6.5 How significant is interspecific 6.5 How significant is interspecific competition in practice?competition in practice?
6.5.1 the prevalence of current competition6.5.1 the prevalence of current competitionSchoener (1983), 164 studies, terrestrial Schoener (1983), 164 studies, terrestrial
plants, terrestrial animals and marine plants, terrestrial animals and marine organisms.organisms.
Connell (1983), 72 studies, 215 species and Connell (1983), 72 studies, 215 species and 527 different expetiments.527 different expetiments.
6.5.2 Competition or mere chance?6.5.2 Competition or mere chance?
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Schoener (1983)Schoener (1983) Found that approximately 90% of the studies had Found that approximately 90% of the studies had
demonstrated the existence of interspecific demonstrated the existence of interspecific competition, and that the figures were 89%, 91% and competition, and that the figures were 89%, 91% and 94% for terrestrial, freshwater and marine organisms, 94% for terrestrial, freshwater and marine organisms, respectively.respectively.
Connell (1983)Connell (1983) Interspecific competition was demonstrated in most of Interspecific competition was demonstrated in most of
the studies, more than half of the species and the studies, more than half of the species and approximately 40% of the experiments.approximately 40% of the experiments.
In contrast to Schoener, Connell found that In contrast to Schoener, Connell found that interspecific competition was more prevalent in interspecific competition was more prevalent in marine than in terrestrial organisms, and also that it marine than in terrestrial organisms, and also that it was more prevalent in large than in small organisms.was more prevalent in large than in small organisms.
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6.5.2 competition or mere chance?6.5.2 competition or mere chance?
Neutral models, Neutral models, Null hypothesisNull hypothesis
Niche differentiation,Niche differentiation,Morphological differentiationMorphological differentiationNegatively associated distributionsNegatively associated distributions
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6.3 Quantitative aspects6.3 Quantitative aspectsNeutral models of lizard communitiesNeutral models of lizard communities
Lawlor (1980) investigated differential resource Lawlor (1980) investigated differential resource utilization in 10 North American lizard utilization in 10 North American lizard communities, consisting of four to nine species.communities, consisting of four to nine species.
For each community, there were estimates of For each community, there were estimates of the amounts of each of 20 food categories the amounts of each of 20 food categories consumed by each species.consumed by each species.
This pattern of resource use allowed the This pattern of resource use allowed the calculation, for each pair of species in a calculation, for each pair of species in a community, of an index of resource use overlap, community, of an index of resource use overlap, which varied between 0 and 1. which varied between 0 and 1.
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Fig. 6.19 the mean indices of resource use Fig. 6.19 the mean indices of resource use overlap for each of 10 North American lizard overlap for each of 10 North American lizard communities are shown as solid circles.communities are shown as solid circles.
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Questions Questions
What is the ‘ghost of competition past’? What is the ‘ghost of competition past’? Why is it impossible to prove an Why is it impossible to prove an evolutionary effect of interspecific evolutionary effect of interspecific competition?competition?
Define fundamental niche and realized Define fundamental niche and realized niche. How do these concepts help us to niche. How do these concepts help us to understand the effects of competitors?understand the effects of competitors?
