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Ecosystem Restoration

Ecosystem Restoration. Repaying the Ecological Debt. Conceptual issues. After manipulation of a natural system, have three choices:. Ecosystem Restoration. Restoration – bring back to pre-disturbance condition Rehabilitation – partial replacement of original ecosystem

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Ecosystem Restoration

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  1. Ecosystem Restoration Repaying the Ecological Debt

  2. Conceptual issues After manipulation of a natural system, have three choices:

  3. Ecosystem Restoration Restoration – bring back to pre-disturbance condition Rehabilitation – partial replacement of original ecosystem Enhancement – alternative ecosystem Note: to understand above scenarios of recovery have to consider two biological factors of colonization and succession

  4. Colonization and Succession - Both are ecosystem changes with time • Colonization – arrival of new species in an empty patch Colonization of “bare” areas based on MacArthur and Wilson theory of island biogeography  CONSIDER DENUDED PATCHES AS ISLANDS Ex. Clear-cuts, strip mine are islands in a “sea” of mixed deciduous forest

  5. Seq S = Seq (1-e -Gt) ∆S G = ____ = colonization rate Species (s) ∆t Time (t) • Number of species depends on colonization rate (G) • G starts out high, gets smaller and smaller • Colonization rate based on two relationships

  6. inhospitable terrain Species source (mainland, deciduous forest) “islands” (clear-cut, toxic waste site, strip mine) ▲ Longer distance from source (mainland) = lower # of species

  7. inhospitable terrain Larger patches = higher probability of being “hit” by propagules ▲ Increased size/area = increased # of species on islands

  8. Seq

  9. Proximity to source Kind of organism (vagility) Reproductive rate (r- vs K-selection) Air, water currents (rafting) Residual disturbance, toxics Competition Habitat diversity and quality Generalist/Specialist Factors Affecting Colonization Rates Immigration Extinction Note: once reach equilibrium  dynamics become interactive = succession

  10. Non-interactive Interactive = succession Seq Species (s) Time (t)

  11. Succession • Orderly change in community composition over time • Usually follows colonization  especially studied in plant communities • Two models • relay floristics • initial floristics

  12. Relay floristics Abandonment Crop Weeds | Grassland | Shrubland | Forest Species Years

  13. Initial floristics Abandonment Crop Weeds | Grassland | Shrubland | Forest Species Years

  14. Implications for Reserve Design betterworse A B C D E F

  15. Significance to restoration of altered ecosystems • Relay floristics – ongoing process based on external input • Initial floristics – happens all at once based on internal input ▲Might have to manage system to help recovery - stock fish - soil stabilization with annual plants - etc.

  16. Tionesta Natural Area, Allegheny National Forest, PA Photo by R. Grippo

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