Competition in theory one individual uses a resource, reducing its availability to others...
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Transcript of Competition in theory one individual uses a resource, reducing its availability to others...
![Page 1: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/1.jpg)
![Page 2: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/2.jpg)
Competition in theory
• one individual uses a resource, reducing its availability to others
• negative-negative interaction– intraspecific competition – interspecific competition– interference competition– exploitative competition– diffuse competition– apparent competition
![Page 3: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/3.jpg)
Exploitative and interference competition.
![Page 4: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/4.jpg)
The competitive exclusion principle
• two species cannot coexist if they both depend on the same limiting resource
![Page 5: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/5.jpg)
The competitive exclusion principle
• two species cannot coexist if they both depend on the same limiting resource
• disturbance and predation
• habitat heterogeneity• metapopulation
dynamics
![Page 6: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/6.jpg)
Lotka-Voltera competition model
• adding a competing species j reduces the growth rate and the steady state equilibrium population of species i
j
iji
j
jjj
j
i
jij
i
iii
i
K
Na
K
NNr
dt
dN
K
Na
K
NNr
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dN
1
1
![Page 7: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/7.jpg)
Lotka-Voltera competition model
• competition coefficients aij and aji express the effects of each competitor in terms of the other competitor’s resource use– competition coefficients
usually α and β– aij means “the effect of
each member of species j on species i”
j
iji
j
jjj
j
i
jij
i
iii
i
K
Na
K
NNr
dt
dN
K
Na
K
NNr
dt
dN
1
1
![Page 8: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/8.jpg)
Lotka-Voltera competition model
• (a) per-capita growth rate for species i– zero growth isocline in the
(Ni, Nj) plane
• (b) ZGI for species i– Ni → Ki only when Nj → 0– Ki/aij is the equilibrium
population of species i expressed in “equivalent units” of species j
• (c) ZGI for species j
![Page 9: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/9.jpg)
Lotka-Voltera competition model
• species i zero growth isocline crosses the Ni axis at Ki and the Nj axis at Ki/aij
• species j zero growth isocline crosses the Nj axis at Kj and the Ni axis at Kj/aji
![Page 10: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/10.jpg)
Lotka-Voltera competition model
• species i zero growth isocline crosses the Ni axis at Ki and the Nj axis at Ki/aij
• species j zero growth isocline crosses the Nj axis at Kj and the Ni axis at Kj/aji
• the species with the outer ZGI wins (Ni)
![Page 11: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/11.jpg)
Lotka-Voltera competition model
• coexistence can occur when the zero growth isoclines cross one another
• equilibrium with both populations > 0
• stable if intraspecific competition limits growth before interspecific competition
![Page 12: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/12.jpg)
Lotka-Voltera competition model
• coexistence can occur when the zero growth isoclines cross one another
• equilibrium with both populations > 0
• unstable otherwise• outcome depends on
starting population sizes
![Page 13: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/13.jpg)
Lotka-Voltera competition
Rhizopertha and Oryzaephilus Rhizopertha and Sitotraga
![Page 14: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/14.jpg)
Resource competition model
• the Lotka-Voltera models do not express competitive interactions in terms of resource consumption
• zero growth isoclines for a single species with two limiting resources
![Page 15: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/15.jpg)
Resource competition model
• the Lotka-Voltera models do not express competitive interactions in terms of resource consumption
• zero growth isoclines for a single species with two limiting resources
R2*
R1*Resource 1
Res
ourc
e 2
![Page 16: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/16.jpg)
Resource competition model
R2*
R1*Resource 1
Res
ourc
e 2
iA
B
• zero growth isoclines for a single species with two limiting resources
• consumption vector reflects an optimal resource use ratio
• resource supply points and depletion vectors
• species i is excluded from the shaded area
![Page 17: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/17.jpg)
Resource competition model
• trivial example of ZGI’s for two species competition
• Ni always wins
![Page 18: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/18.jpg)
Resource competition model
• two species competition• outcome depends upon
initial resource supply point and joint depletion vectors
j
R2i*
R1i*
Resource 1
Res
ourc
e 2
R2j*
R1j*
i
j
i onl
y
j only
i exc
lude
s j
j excludes i
Both coex
ist
![Page 19: Competition in theory one individual uses a resource, reducing its availability to others negative-negative interaction –intraspecific competition –interspecific.](https://reader030.fdocuments.us/reader030/viewer/2022032722/56649cee5503460f949bb490/html5/thumbnails/19.jpg)
Resource competition model
• two species competition• outcome depends upon
initial resource supply point and joint depletion vectors
• ZGIs and consumption vectors for two diatom species