Disturbance mosaics (treefall gaps, hurricanes, fires)

1
Disturbance mosaics (treefall
gaps, hurricanes, fires)

• Patchy, recurrent disturbance
• Habitat states vary demographically
• Habitat states change over time
• Dynamics includes demographic and habitat
  transitions

2
Concepts

• Structured populations
• Mosaic of habitat-states
• Each habitat state
• one population projection matrix
• Entire heterogeneous landscape
• set of matrices

3
Many different ways to link together...

• arithmetic average
• products of matrices (a fixed sequence)
• stochastic sequence simulation
• megamatrix analytical

4
Megamatrix

• Habitat-by-stage classes
• Matrix size
  no. of habitats x no.
  stages
• Habitat transition matrix
• Aggregates over all patches of a given habitat at
  each time step

5
Habitat transition matrix
6
Habitat characteristics from a matrix?

• Projection of relative abundance of habitat
  types through time
• Equilibrium habitat structure

7
Habitat transition phenology
census
census
time
t
t1
late habitat change
early habitat change
8
Megamatrix early habitat type change
9
Megamatrix late habitat type change
10
New sensitivity questions

• Habitat by life history stage classification
• Do life-history events in different habitats
  differ in elasticity?
• Elasticities (can be summed)
• habitat
• stage across all habitats
• stage within habitats
• and more

11
Whats next?

• Time averages
• Cumulative pop growth
• Stochastic sequences
• Synthesis