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Disturbance ecology

Disturbance ecology. Formalized with the publication “The Ecology of Disturbance and Patch Dynamics” in 1985 Non-equilibrium perspectives communicated through new terms like: Disturbance patch dynamics Disturbance regime Disturbance residuals Environmental heterogeneity Disturbance agent.

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Disturbance ecology

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  1. Disturbance ecology • Formalized with the publication “The Ecology of Disturbance and Patch Dynamics” in 1985 • Non-equilibrium perspectives communicated through new terms like: • Disturbance patch dynamics • Disturbance regime • Disturbance residuals • Environmental heterogeneity • Disturbance agent .

  2. Disturbance patch dynamics

  3. Disturbance regime • Disturbances are characterized by their disturbance regime: its frequency in time, its extent or size in space, and its intensity and severity

  4. Disturbance residuals/ biological legacies

  5. Environmental heterogeneity

  6. Fire disturbance • Fires release nutrients stored in biomass. • Light is made available to the understory after fire • Alters the age distribution and structure of forest trees. • Tree species killed depends upon the intensity of the fire

  7. Flood disturbance

  8. Geomorphic disturbances

  9. Treefall disturbance

  10. Pests and disease

  11. Fraser fir in Appalachians. Dense stand at left is emblematic of forests before the invasion of the balsam wooly adelgid.

  12. 1959 Fraser fir before invasions of non-native balsam wooly adelgid

  13. 2008 Fraser fir after

  14. Disturbance principles for policy • Disturbance is common in nature and may even be necessary for some species to flourish Fire scars in longleaf pine growth rings indicating regular, natural fire interval. Longleaf is a fire-dependent species. In the absence of fire, this species declines in abundance. There are many fire-dependent pine species across North American forests.

  15. Former extent of longleaf pine forests. This forest type is now greatly reduced across this range because of logging and fire suppression

  16. Adaptations to fire in longleaf pine Cone serotiny Grassy stage Punctuated growth

  17. Disturbance principles for policy Fire suppressed longleaf pine forest in Florida Fire in southern California in chaparral vegetation (right) • Removal of natural disturbances can have a negative impacts. Disturbance in this sense becomes the absence of the historic disturbance regime.

  18. Disturbance principles for policy • The extent to which a disturbance has been historically prevalent for an area determines species responses, their abundance, and evolution. Volcanic eruptions Natural fire regime

  19. Seasonal inundation in the Pantanal

  20. Disturbance principles for policy • Natural disturbance is not necessarily a disaster – it can promote species coexistence

  21. Disturbance principles for policy • Resource extraction practices began to mimic natural disturbances. Selective logging and limiting the size of clear cuts are an attempt to mimic natural forests disturbances

  22. Disturbance principles for policy • Because disturbance is common, unrealistic to manage land with the intent of keeping it the same. It is not possible to preserve wilderness if by definition it must change.

  23. Disturbance principles for policy • Disturbance are often coupled and may influence one another

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