Marbled Salamander Metapopulation Dynamics Ramas GIS Metapopulation Model

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Marbled Salamander Metapopulation DynamicsRamas
GIS Metapopulation Model

• 1.Ethan Plunkett
• 2.Sekar Iyyapazham
• 3. Alfred Kikoti

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Metapopulation Definitions

• Mainland-island metapopulation System of
  habitat patches (islands) located within
  dispersal distance from a very large habitat
  patch (mainland) where the local population
  never goes extinct (hence mainland-island
  metapopulations do not go extinct). (Hanksi and
  Simberloff, 1997)

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Not a mainland island metapopulation
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Metapopulation Definitions

• Nonequilibrium metapopulation Metapopulation in
  which (long-term) extinction rate exceeds
  colonization rate or vice versa an extreme case
  is where local populations are located so far
  from each other that there is no migration
  between them and hence no possibility for
  recolonization (Hanksi and Simberloff, 1997)

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Population is not a Non-equilibrium
metapopulation
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Metapopulation Definitions

• Patchy metapopulation Metapopulations that are
  so well mixed and interconnected by dispersal
  that they function essentially as a single
  population. Local extinctions are recolonized
  immediately and a single individual might live in
  multiple patches during its lifetime.
  (McGarigal, 2005)

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Not a Patchy Population
Abundance
Pool Number
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Metapopulation Definitions

• Classic (Levins) metapopulation A large network
  of similar small patches, with local dynamics
  occurring at a much faster time scale than
  metapopulation dynamics in a broader sense used
  for systems in which all local populations, even
  if they differ in size, have a significant risk
  of extinction. (Hanski and Simberloff, 1997)

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Metapopulation Definitions

• Classic (Levins) metapopulation Idealized
  system, comprising multiple patches whose
  populations are reciprocally linked and have
  equal probabilities of colonization and
  extinction. (McGarigal, 2005)

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Metapopulation Definitions

• Source-sink metapopulation Metapopulation in
  which there are patches in which the population
  growth rate at low density and in the absence of
  immigration is negative (sinks) and patches in
  which the growth rate at low density is positive
  (sources). (Hanksi and Simberloff, 1997)

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Metapopulation Definitions

• Source-sink metapopulation A source has a
  positive local recruitment rate in the absence of
  immigration, and thus provides a net surplus of
  emigrants. A sink has negative local recruitment
  and so would not persist in the absence of a
  dispersal subsidy from elsewhere. The source
  population is resistant to extinction while some
  subset of sink populations tend to go extinct
  repeatedly and be recolonized by dispersal from
  the source (Pulliam 1988 as summarized by
  McGarigal notes).

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Individual Pond Trajectories
Pond 2
Pond 1
Pond 4
Pond1
Pond 12
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PART 2
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Interval Extinction Risk
Low Dispersal
No Dispersal
High Dispersal
Probability
Medium Dispersal
Interval Extinction Risks High Dispersal
0.0 Medium Dispersal 0.012 Low Dispersal
0.064 No Dispersal 0.064
Threshold
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POND 4
Population Trajectory
No Dispersal
Low Dispersal
Medium Dispersal
High Dispersal
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Population Trajectory
POND 6
Low Dispersal
No Dispersal
Medium Dispersal
Population
High Dispersal
Time
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Trajectory Summary
(Overall Population Size)
High
Medium
Abundance
Low
No
Time
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PART 3
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Interval Extinction Risk (Varying rates of
correlation among pools catastrophic events)
Full Correlation
Med High Correlation
Low Correlation
Interval Extinction Risks No correlation
0.018 Low correlation 0.056 Medium correlation
0.122 Full correlation 0.21
No Correlation
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Interval Explosion Risk
Full Correlation
No Correlation
Med High Correlation
Low Correlation
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Population Trajectory
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Part 4
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Developers Scenario
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Abundance
Pool
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Ponds 1, 3, and 14
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Ponds 1, 6, and 14
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Ponds 8, 9, and 10
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Interval Extinction Risk
Developers Scenario
No Development
Probability
Extinction Risks No Development
0.052 Development Pools 4, 5, and 7
0.264 Pools 1, 6, and 14 0.080 Pools 1, 3, and
14 (with pool 2 isolated) 0.068 Pools 8, 9, and
10 0.056
Threshold
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