The niche is an organizing concept in ecology
A habitat is the place where an organism lives
California’s intertidal system has distinct habitat zones that reflect tidal action
High Tide Zone
Middle Tide Zone
Low Tide Zone
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A habitat meets essential requirements for a species' survival and reproduction
• Abiotic factors
– temperature, water availability, elevation, slope, aspect, soil type, pH, salinity, dissolved oxygen, etc.
etc
• Biotic factors
– food, nesting, support, cover, nutrients, etc.
• Interactions of these
Where you find a species also depends on its ecological tolerances
Too cold
Too dry
Too hot
Performaance
Many ecological tolerances can be represented as a bell shaped response curve
Reprod.
Growth
Survival
Factor or Condition
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Species differ in their ecological tolerances
Temperature oC
Species
(m)
Oxyria digyna
2500
Geum reptans
2500
Pinus cembra
1900
Betula pendula
1900
Picea abies
1900
Larix decidua
900
Leucojum vernum
600
Fagus sylvatica
600
Taxus baccata
550
Abies alba
530
Prunus laurocerasus
250
Olea europaea
240
Quercus pubescens
240
Citrus limonum
5
10
15
20
25
30
Temp range of net
photosynthesis
80
The ecological niche refers to how an organism fits into an ecological system
The modern concept of the niche
incorporates requirements and tolerances
• Early “place” ideas
– Grinnell (1917 – 1924)
• The functional niche
– Elton (1927, 1933)
– Gause (1934)
• A unified approach
– Hutchinson (1957)
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Temp.. tolerance
Temperatture
Hutchinson’s idea provided a way to quantify the niche of a species
the fundamental
th
f d
t l
niche
Prey size requirement
Prey size
Foraging height (m)
A feeding niche (in 2 dimensions) for the blue‐
gray gnatcatcher
Highest percent of diet Prey length (mm)
Foraging he
eight
Hutchinson’s concept also extended to account for species interactions
Species 1
Species 2
Species 3
Prey size
4
Foraging he
eight
The realized niche is determined by interactions with other species
Realized niche of Species 1
Fundamental niche
Species 1
Species 2
Species 3
Prey size
The niche concept in two species of barnacles
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