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Biological proxies

Biological proxies. Plants as indicators of terrestrial environments. Tissue/organs: Support --> wood (tree rings) Photosynthetic --> leaf anatomy (stomata) Reproductive --> pollen, (cones) seeds Detritus --> charcoal. Dendroclimatology: basics.

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Biological proxies

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  1. Biological proxies

  2. Plants as indicators of terrestrial environments Tissue/organs: Support --> wood (tree rings) Photosynthetic --> leaf anatomy (stomata) Reproductive --> pollen, (cones) seeds Detritus --> charcoal

  3. Dendroclimatology:basics • Plants are responsive to variations in the ambient physical environment; • Response is expressed by variations in growth, reproductive effort, etc.; • Growth response is recorded in woody (nontropical) trees by variations in the thickness of annual rings; • The environmental stimuli can be revealed by analyzing ring widths of living or fossil trees from sensitive sites.

  4. annual rings complacent Environment - site interactions temperature-sensitive drought-sensitive bark

  5. Tree rings as proxies

  6. Measuringtree ringwidths

  7. Tree ring records, N. Eurasia (AD 0 - 2000)

  8. Spatial patterns:the megadrought of 1863 in the USA

  9. Reconstructing fire history from scars and wounds

  10. Fire history sites, SW USA

  11. Constructing regional fire histories

  12. Tree rings and volcanism dust veil narrow/frost rings record eruptions in spring/summer only? ‘frost ring’ e.g. LaMarche and Hirschboeck, 1984, Nature 307, 121-126

  13. Hemispheric analysesof tree ring density reveal annual and spatial variations in climate[Northern hemisphere; AD 1815-1817] Eruption of Tambora “The year without a summer” continues

  14. Palynology: pollen proxies • Plants produce morphologically distinctive pollen grains. • Pollen “rain” is representative of the local plant community (apart from non-anemophilous spp.). • Pollen grains are extremely resistant to decay in anoxic conditions (e.g. lake sediments, peat bogs, wetland soils). • Pre-existing plant communities can be reconstructed by sampling fossilassemblages in these sedimentaryarchives. • Palaeoclimates can be derived from the ecological ranges of the constituent species.

  15. Pollen morphology I

  16. Pollen morphology II

  17. Pollen types Pinus Tsuga Poaceae Achillea

  18. Species range, pollen rain and environment Tsuga occidentalis range limits % isopolls Temperature (°C) Jan. Ann. July -20 -10 0 10 20 30 Precipitation (mm) Jan. Ann. July 1 10 100 1000 10000

  19. Relative pollen % and summer temperature (Yukon)

  20. Pollen capture by lakes 100 REGIONAL (UP TO SEVERAL HUNDRED KILOMETRES FROM LAKE) EXTRA-LOCAL (20 TO SEVERAL HUNDRED METRES FROM LAKE) % TOTAL POLLEN LOCAL (<20 METRES FROM LAKE) 0 0 100 200 300 1000 LAKE DIAMETER (M)

  21. R = 1; pollen production = species abundance in vegetation Pollen representation (‘R-value’: Inuvik area) “Over” “Equal” “Under” alder 11.8 juniper 1.0 spruce 0.5 sage 5.0 willow 0.6 larch 0.2 grass 3.4 poplar 0.6 heaths 0.1 birch 3.0 sedge 2.2

  22. Pine pollen percentage vs. influx (Rogers Lake, Connecticut) Pine needles (regional pattern) 0 2000 4000 6000 8000 10000 12000 14000 Radiocarbon yrs BP Late Holocene Glacial 0 20 40 600 10 20 % of totalInflux (‘000 grains/cm2/yr)

  23. Plant macrofossilsas proxies

  24. Stomatal patterns Monocots (linear) Dicots (random)

  25. Stomatal density and [CO2]

  26. Reconstructed atmospheric CO2 levelsfrom300 Ma to PD

  27. Regional fires (background) Charcoal influx(mm2 cm-2 yr-1), Lake Francis, Abitibi, Québechttp://www.consecol.org/vol2/iss2/art6 Local fires

  28. Insect proxies (e.g. Coleoptera [beetles]) head capsule pronotum elytra (singular= elytron) 1. Fossil extraction (washing [solvents include kerosene] & sieving). 2. Taxon ID: morphology, microsculpture & genitalia (X100)

  29. Beetles in UK “Devensian” deposits (=OIS 2/3) A-C = thermophilesD-G = tundra /alpinesH = cosmopolitanspecies(after Coope) barren = full glacial

  30. Modern ranges of cold-tolerant beetles from UK Devensian deposits

  31. Modern ranges of thermophile beetles from UK Devensian deposits

  32. Devensian exotica(periglacial deposits) “interglacial refuge”

  33. Terrestrial shelly invertebrates

  34. Terrestrial vertebrates Alan Griffiths; discoverer of fossil bear bones, QCI, from ~15 ka BP (map of Late Glacial vertebrate fossil finds) Photos: Vancouver Sun

  35. Packrat middens Neotoma cinerea midden site (Colorado) sampling a midden fossil extraction

  36. (BC) Packrat middens:sample sites

  37. Pinus edulis: distribution records in US SW from packrat middens

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