Ecological Niches: Past, Present and Future

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Ecological Niches Past, Present and Future

• Luke L. Powell
• LSU Renewable Natural Resources

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Grinnell (1917)

• The place in an environment that a species
  occupies

California thrasher, Toxostoma redivivum Photo
from Wikipedia
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Gause (1936)

• Competitive exclusion principle
• No two species with identical competitive
  effects on one another can exist locally

Photo www.nceas.ucsb.edu/alroy/lefa/Gause.jpg
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G. Evelyn Hutchinson (1957)
An n-dimensional hypervolume???

• Lets consider the concept of niche
• If I knew what it meant Id be rich.
• Its dimensions are n
• But a knowledge of Zen
• Is required to fathom the bitch.
• -Cottam and Parkhust

Photo from Yale Peabody Archives Figure from
wiki.verkata.com
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A single-axis (i.e. single-dimension)
fundamental niche
Range of temperature tolerance
just right
Too hot
Too cold
Temperature
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Another single-axis fundamental niche
Range of salinity tolerance
just right
Too salty
Too fresh
Salinity
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A two-axis fundamental niche
Too salty
ok
Too cold
Too hot
Salinity
Too fresh
Temperature
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A two-axis realized niche
Niche of a superior competitor
Too salty
ok
Too cold
Salinity
Too hot
Area of fundamental niche lost due to competition
Too fresh
Realized niche after competition
Temperature
Too much overlap Competitive exclusion!
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A three-axis realized niche for trees

• X Mesophytism
• Y Soil drainage conditions
• Z Disturbance

Fig Whittaker 1973 Am. Nat. v. 107(955)
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G. Evelyn Hutchinson (1957)
An n-dimensional hypervolume???
Photo from Yale Peabody Archives Figure from
wiki.verkata.com
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Robert MacArthur (1958)
Photo Wikipedia Painting Debbie Kaspari
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Robert MacArthur (1958)

• Actually, to permit coexistence, it seems
  necessary that each species, when very abundant,
  should inhibit its own further increase more than
  it inhibits the others.

K1 / a
Intraspecific competition (i.e. organisms effect
on envt.)
N2
K2
K1
K2 / ß
N1
Photo Wikipedia Graph Modified from Kyles
stable equilibrium
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Community Ecology of Neotropical Kingfishers
Species Packing Mechanisms

• James Van Remsen Jr.
• University of California Publications in Zoology
  v. 124. 1991.

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• Objective Determine the proximate mechanism that
  explains the change in species number between the
  five- and three-species communities

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• Map from www.geographigguide.net

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• Megaceryle torquata, Ringed Kingfisher

Chloroceryle amazona, Amazon Kingfisher
Photo Diego Sanches, Wikipedia
Photo LIP Kee Yap, Wikipedia
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Chloroceryle americana, Green Kingfisher
Chloroceryle inda, Green-and-Rufous Kingfisher
Photo Hans Hillewaert, Wikipedia
Photo Alberto Garcia Rios, Internet Bird
Collection

• Chloroceryle aenea,
• American Pygmy Kingfisher

Photo Uncredited, Wikipedia
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Niche-breadth Mechanism

• Prediction narrower niche-breadths in more
  diverse communities

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Niche-breadth Mechanism

• Conclusion No evidence for hypothesis

Where niche breadth 1/? (Pij)2 P is proportion
of diet measured over j prey length categories

? NARROWER?
? BROADER?
? BROADER?
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Niche-overlap Mechanism

• Prediction niche overlaps will be greater in
  more diverse communities

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Niche-overlap Mechanism

• Niche Dimentions
• Prey Length
• Distance of dive entry point from shore
• Habitat
• Open/shaded

• Photo by Claude
• Schneider
• http//www.claudeschneiderphotography.com

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(3-axis) Niche-overlap Mechanism

• Result Niche overlap significantly greater in
  larger community (P lt 0.05)

More overlap
Less overlap
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Resource-base Mechanism

• Prediction directional reduction in resource
  base excludes species

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Resource-base Mechanism
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Resource-base Mechanism
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Criticism of Remsen (1991)

• Niche axes not consistent among hypothesis tests
• No way to quantify relative importance of
  mechanisms
• Prey size confounded by habitat
• Results dependent on method of calculation of
  niche overlap

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Chase and Leibold (2003)

• Niche
• The environmental conditions that allow a
  species to satisfy its minimum requirements so
  that the birth rate of a local population is
  equal or greater than its death rate along with
  the set of per capita impacts of that species on
  these environmental conditions.

Requirement component
Niche
Impact component
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Chase and Leibold (2003)
Slope of Impact component for Sp 1
ZNGI Sp 1
Slope of Impact component for Sp 2
Sp 2 ALONE
COEXIST
Resource A
Sp 1 ALONE
ZNGI Sp 2
Can replace Resource With predator Or stress
Stresses a two-dimensional approach
Resource B
Impact Components
Graph Modified from Kyles
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Criticism of Remsen (1991)

• Niche axes not consistent among hypothesis tests
• No way to quantify relative importance of
  mechanisms
• Prey size confounded by habitat
• Results dependent on method of calculation of
  niche overlap
• Impact component not considered

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Future Application of Niche Research

• Species distribution along gradients
• Temperature
• Precipitation
• Stressors associated with fragmentation

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Context
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Acknowledgements

• Phil Stouffer for template of slides on
  fundamental vs. realized niche
• Kyle Harms for use of graphs and help with
  literature and organization

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THANKS

• Drawings by Jan Dungel
• www.jandungel.com

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Chase and Leibold Sorting on Gradients

• The axis of factors along which species interact,
  be they resources, predators, or stresses, can be
  used to envision a gradient in these factors when
  we expand our view to a regional spatial scale.

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Elton (1927)