Landscape Disturbance

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Landscape Disturbance

• Disturbance defined as
• Relatively discrete event in time
• Disrupts possible multiple hierarchal levels

White and Pickett 1985
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Landscape Disturbance

• Disturbance defined as
• Changes resources, substrate, or physical
  environment

White and Pickett 1985
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Landscape Disturbance

• Disturbance defined as
• Catastrophes to more subtle fluctuations
• Ultimately causes significant change in system

White and Pickett 1985
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Landscape Disturbance

• Perturbation change in parameter (state
  variable) departing from normality

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Landscape Disturbance

• Characteristics of Regime
• Area/size
• Spatial distn
• Frequency
• Recurrence interval
• Predictability
• Intensity/severity
• Synergisms
• Feedbacks

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Landscape Disturbance

• Type Agent
• Physical
• Biological
• Interaction
• Origin of Agent
• Endogenous
• Exogenous

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Disturbance Types
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Landscape Disturbance

• Disturbance history
• Time scale
• Context

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Landscape Disturbance

• Complexity of interactions
• Macroclimatic patterns
• Landscape position
• Vegetation

Boose et al. 1994
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Landscape Pattern Spread of Disturbance

• Generalities possible?
• If disturbance spreads within same cover type,
  then greater heterogeneity should retard spread
  (e.g., spruce budworm, lower intensity fires)

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Landscape Pattern Spread of Disturbance

• Generalities possible?
• If disturbance spreads between cover types or is
  edge-enhanced, then increased heterogeneity
  should enhance spread (e.g., windthrow, tent
  caterpillar)

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Landscape Pattern Spread of Disturbance

• Generalities possible?
• If disturbance is severe enough or of large
  enough extent, then may function independent of
  landscape pattern

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