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Quaternary Environments Quaternary Ecology

Quaternary Environments Quaternary Ecology. Paleoecological Studies. Cannot establish experiments and replicate them Look for evidence of events that occurred through time and use these “natural experiments” of the past to generate hypotheses Substitution of Space for Time. Pollen Analysis.

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Quaternary Environments Quaternary Ecology

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  1. Quaternary EnvironmentsQuaternary Ecology

  2. Paleoecological Studies • Cannot establish experiments and replicate them • Look for evidence of events that occurred through time and use these “natural experiments” of the past to generate hypotheses • Substitution of Space for Time

  3. Pollen Analysis • One of our best records of vegetation assemblages • Allows us to test hypotheses

  4. Venn Diagrams of Analogue Situations

  5. Detrended Correspondence Analysis (DCA) of Forest Communities of Eastern North America

  6. Tauber’s Model of Pollen Transport in a Forested Landscape Where: Cg – Gravity, Ct – Trunk Space, Cc – Canopy, Cr – Rain, Cw – Flowing Water Bradshaw’s model for the relationship between the diameter of the pollen catchment and its pollen source area.

  7. Scale Issues • In any ecological or paleoecological study, the organism or population is best viewed in a context of its life span, life history strategy, recurrence interval and magnitude of disturbances

  8. Spatial and Temporal Domains for a Hierarchical Characterization of Environmental Forcing Factors

  9. Environmental Disturbance Regimes, Biotic Responses, and Vegetation Patterns Viewed in the Context of Four Space-Time Domains.

  10. Succession • Clements’ View • Plant community associations that remain intact • Gleason’s View • Species are distributed individualistically according to their tolerances

  11. Changes in Northern Arizona Vegetation Zones from Packrat Middens from the Grand Canyon

  12. Gradient Studies and Elevational Effects During the Last Glacial Maximum

  13. Vegetation Change over the last 18,000 years in the Northern Great Basin

  14. Changes in Northern and Western Range Limits for Four Important Eastern North American Tree Taxa During the Late Quaternary Based on Pollen Records.

  15. Maps Depicting Changes in Range Limits Expressed in Contoured Values of Percent Dominance in Forests for Oak. http://www.ngdc.noaa.gov/paleo/pollen/viewer/webviewer.html

  16. Individualistic Response • Cold Hardiness • Response to Disturbances

  17. Lower Cold Hardiness Thresholds (Killing Temperatures) Summarized for 25 Woody Angiosperms from the Eastern Deciduous Forest.

  18. Cold Hardiness Zone Map. Region A less than -40 ºC Region B may reach -40 ºC Region C does not reach -40 ºC

  19. Disturbances • Fire • Itasca State Park, Northwestern Minnesota • Western Margin of the Hemlock-White Pine-Northern Hardwood Forest Region • Changing Fire Frequency 33 or 44 years to 80-90 years • Climate • Controls Vegetation • Feedbacks to Fire • Insect Outbreaks

  20. Changes in Fire Frequency in Northwestern Minnesota reflected in a Shift from a 44-year Cycle to an 88-year Cycle (from Clark 1988)

  21. Distinct Vegetation Types Due to Critical Climatic Thresholds

  22. Vegetation Dependence on Climatic Factors Controlling Final Stable Vegetation State

  23. Tree Species Decline and Recovery Due to Pathogens from Pout Pond, New Hampshire

  24. Pollen Accumulation Rates for Black Ash and Ironwood/Hornbeam for the Late-Glacial Interval

  25. Forest Models • FORET • JABOWA

  26. Human Evolution

  27. North American Land Mammal Ages

  28. Megafaunal Extinction

  29. Pleistocene Extinctions

  30. Radiocarbon-Dated Megafauna

  31. Timing of Megafaunal Extinctions at Different Locations (from Sturart et al., 2004 )

  32. Worldwide Megafaunal Extinctions

  33. Land Bridges During the Last Glacial Maximum

  34. Human Expansion into the Americas

  35. Marine Overkill

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