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 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.

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

Tree rings as proxies

Measuring tree ring widths

Tree ring records, N. Eurasia (AD )

Spatial patterns: the megadrought of 1863 in the USA

Reconstructing fire history from scars and wounds

Fire history sites, SW USA

Constructing regional fire histories

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

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

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 fossil assemblages in these sedimentary archives. Palaeoclimates can be derived from the ecological ranges of the constituent species.

Pollen morphology I

Pollen morphology II

Pollen types Pinus Tsuga Poaceae Achillea

Tsuga occidentalis range limits % isopolls Species range, pollen rain and environment Temperature (°C) Ann. Jan. July Precipitation (mm) Ann. Jan. July

Relative pollen % and summer temperature (Yukon)

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

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 R = 1; pollen production = species abundance in vegetation

Pine pollen percentage vs. influx (Rogers Lake, Connecticut) Radiocarbon yrs BP % of total Influx (‘000 grains/cm 2 /yr) Late Holocene Glacial Pine needles (regional pattern)

Plant macrofossils as proxies

Stomatal patterns Monocots (linear) Dicots (random)

Stomatal density and [CO 2 ]

Reconstructed atmospheric CO 2 levels from 300 Ma to PD

Charcoal influx (mm 2 cm -2 yr -1 ), Lake Francis, Abitibi, Québec /vol2/iss2/art6 Local fires Regional fires (background)

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

Beetles in UK “Devensian” deposits (=OIS 2/3) A-C = thermophiles D-G = tundra /alpines H = cosmopolitan species (after Coope) barren = full glacial

Modern ranges of cold-tolerant beetles from UK Devensian deposits

Modern ranges of thermophile beetles from UK Devensian deposits

Devensian exotica (periglacial deposits) “interglacial refuge”

Terrestrial shelly invertebrates

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

Packrat middens Neotoma cinerea fossil extractionsampling a midden midden site (Colorado)

Packrat middens: sample sites (BC)

Pinus edulis: distribution records in US SW from packrat middens