2' Tolerance ranges, interactions of environmental factors on distribution, fundamental and realized

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• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Reading in Krebs Ch3 p32-36, Ch7 p90, Ch12
  p190-199, Ch22 p447-8)
• Tolerance ranges
• Interactions of environmental factors
• Role of competition.
• e.g. Competitive balance changed by climate.
  e.g. Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

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Tolerance range
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Tolerance range
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Tolerance range
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• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Krebs Chapter 7)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

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• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Krebs Chapter 7)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

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Nature 439, 161-167 (12 January 2006)
doi10.1038/nature04246
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Widespread amphibian extinctions from epidemic
disease driven by global warming
Monteverde harlequin frog (Atelopus sp.) has
vanished along with the golden toad (Bufo
periglenes). An estimated 67 of the 110 or so
species of Atelopus, which are endemic to the
American tropics, have met the same fate. A
pathogenic chytrid fungus (Batrachochytrium
dendrobatidis) is implicated.
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Air temperature (AT, blue) and Sea Surface
Temperature (SST), red for Monteverde, Costa Rica
Widespread amphibian extinctions from epidemic
disease driven by global warming
Number of species observed for the last time
(black) and air temperature (blue)
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Sedum rosea rose-root
Sedum telephium - Orpine
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Character Displacement

• A shift in the characteristic of a species in an
  area where there is competition while, where
  there is no competition, characteristic is
  different

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• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Krebs Chapter 7)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

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• Gauses hypothesis Two species with a similar
  ecology cannot live together in the same place
• Competitive exclusion principle -Complete
  competitors cannot co-exist

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Fundamental versus Realized Niches

• Fundamental niche
• includes the total range of environmental
  conditions that are suitable for existence
  without the influence of interspecific
  competition or predation from other species.
• Realized niche
• that part of the fundamental niche actually
  occupied by the species in the face of competition

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• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Krebs Chapter 7)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

30

• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Krebs Chapter 7)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

31
Relation between tolerance range in monoculture
and mixtures with respect to environmental
factors - limitations of ecophysiology i.
Experiments e.g. grasses grown in monoculture
and mixtures along a nutrient gradient ii.
Natural occurrence Compare 4 plant species
(Deschampsia flexuosa, Fesuca ovina, Scabiosa
columbaria and Rumex acetosa) Possible cause of
differences between individual tolerance curves
and populations/communities - competition.
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Recap of relevant material in Class 3
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Relation between tolerance range in monoculture
and mixtures with respect to environmental
factors - limitations of ecophysiology i.
Experiments e.g. grasses grown in monoculture
and mixtures along a nutrient gradient ii.
Natural occurrence Compare 4 plant species
(Deschampsia flexuosa, Fesuca ovina, Scabiosa
columbaria and Rumex acetosa) Possible cause of
differences between individual tolerance curves
and populations/communities - competition.
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Relation between tolerance range in monoculture
and mixtures with respect to environmental
factors - limitations of ecophysiology i.
Experiments e.g. grasses grown in monoculture
and mixtures along a nutrient gradient ii.
Natural occurrence Compare 4 plant species
(Deschampsia flexuosa, Fesuca ovina, Scabiosa
columbaria and Rumex acetosa) Probable cause of
differences between individual tolerance curves
and populations/communities - competition.
36

• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Krebs Chapter 7)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.

37
Practical ways to study distribution and
causes Absence of a species may be because it
never reached the area

• Transplant experiments may resolve this.
• If successful establishment and reproduction over
  many generations
• Actual range was less than potential
• Probably absence was due to failure in dispersal.
  May be a dangerous experiment if it cannot be
  eradicated!
• If transplant fails to establish
• Unsuitable physical environment (ameliorate)
• Unfavorable biological factors (exclude
  competitors)

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Practical ways to study distribution and
causes Absence of a species may be because it
never reached the area, cont.(Krebs pp 32-34)
Current distribution does not necessarily
indicate tolerance range
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• 2. Tolerance ranges, interactions of
  environmental factors on distribution,
  fundamental and realized niche
• (Reading in Krebs Ch3 p32-36, Ch7 p90, Ch12
  p190-199, Ch22 p447-8)
• Tolerance ranges
• Interactions of env factors
• Role of competition.
• e.g. Competitive balance changed by climate. e.g.
  Sedum spp, Harlequin frog
• Competitive displacement
• Fundamental and realized niche use
• i. Experiments
• e.g. grasses grown in monoculture and mixtures
  along a nutrient gradient
• ii. Natural occurrence
• Compare 4 plant species (Deschampsia flexuosa,
  Fesuca ovina, Scabiosa columbaria and Rumex
  acetosa)
• Practical ways to study geographical
  distributions of organisms.