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PALEOCLIMATE RECONSTRUCTION: Non-Marine Biologic evidence

PALEOCLIMATE RECONSTRUCTION: Non-Marine Biologic evidence. (plant macrofossils, treelines, pollen, tree rings). These methods typically reveal information for the. Tree-line: zone of decreasing tree height with increasing latitude (arctic) or altitude (alpine).

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PALEOCLIMATE RECONSTRUCTION: Non-Marine Biologic evidence

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  1. PALEOCLIMATE RECONSTRUCTION: Non-Marine Biologic evidence (plant macrofossils, treelines, pollen, tree rings) • These methods typically reveal • information for the

  2. Tree-line: zone of decreasing tree height • with increasing latitude (arctic) or altitude (alpine)

  3. Artic tree-line: corresponds with the

  4. Evidence of retreating tree lines: north or higher than present tree line found north or higher than present tree-line c. Charcoal layers found north or above present tree line—

  5. Evidence for advancing tree lines: • most evidence comes from

  6. is more complex than arctic tree-line due to orographic rainfall and geomorphic processes like landslides growth form of trees near the tree line

  7. Note fluctuation of arctic tree-line during the • last 5000 yr:

  8. Alpine tree-line: • studies in Scandanavia and the western US • concur that alpine tree-lines during the middle • Holocene (~ 5Ka) were ~150 m higher in elevation • than today

  9. Evidence from: • (genus: Neotoma)—the dens • of these animals contain remarkable collections • of the • middens in arid climates have been dated back • as far as • middens indicate that in • the SW US 40Ka –12Ka (this corresponds nicely • with high stands during the same • period—see previous lecture)

  10. middens

  11. : a group of insects restricted to specific climate regimes • One advantage of insects over pollen is that • insects respond quickly to climate change; • whereas it may take years to change the • composition of a forest

  12. This study from a pond in Maine showed that cold water aquatic insects were common during the Younger Dryas

  13. millions of tons of pollen are produced each • year creating a constant ‘rain’ of pollen, which • is • pollen grains are typically 10-150 μm in size • and have distinct morphologies —those that rely on wind for pollination; these produce the most pollen • the method works best for lakes at least 1 km2 • in area—to pick up the

  14. Examples Of different Types of Pollen

  15. Studies of pollen from lakes in the Eastern US show that (today this type of forest is found in Canada and higher elevations of the Appalachians) was found on high elevations of the Appalachians (today tundra is restricted to Northern Canada)

  16. From BIOGEOGRAPHY, Lomolino et al. p. 295

  17. From BIOGEOGRAPHY, Lomolino et al. p. 296

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