Quaternary Environments Non-Marine Biological Evidence

Proxy Records  Macrofossil Evidence  Packrats  Tree-line fluctuation  Microfossil Evidence  Pollen  Insects

Macrofossil Evidence  Quantitative analysis of Quaternary plant macrofossils began in 1957 (West 1957)  Seeds, fruits (orchids to coconuts), cones, sporangia  Leaves, needles, buds  Wood

Macrofossil Seeds

Needle Cross Section

Macrofossil Diagram

Paleoscatology  Scat  Procedure  Blend  Screen  Coprolites Analysis  Can identify food sources and disease

Cuticles  Waxy coating that has distinct morphology  Stomata: control gas exchange  Trichomes (leaf hairs)  Cork cells (provide leaf support)  Silica cells (support, discourage foliavores)

Phytoliths   Production   Silica is deposited in the secondary plant wall of some plants, particularly grasses and occasionally in wood.   Phytoliths most abundant in grasslands and steppes.   Disperal   Large fragments move short distances (fragile) small fragments (silt sized) may be distributed by wind.   Preservation   Resistant to oxidation, but the silica can be dissolved by ground-water movement

Phytolith Morphology

Poaceae Zea luxuriens Phytolith

Poaceae Paspalum lividum Phytolith

Asteraceae Lipochaeta sp. Phytolith

Phytoliths   Identification   Many plants don't produce phytoliths: only a partial indication of plants in area   Non-related species produce the same types : dumbbells, saddles, bowls, boats, bottoms   Some Taxonomic categories can be recognized: panicoid, festucoid, chloroid   A few forms are diagnostic to species level: e.g., maize

Phytolith Methods  Oxidize sample (boil in H 2 O 2 )  Wet sieve (phytoliths silt size)  Flotation (tetrabromoethane, ZnBr2) phytoliths have specific gravity of , quartz 2.65

Wood Anatomy  Can identify wood to the species or genus level  Cell structure  Pits  Tracheids  Pores  Resin ducts

Wood Anatomy

Treeline  Upper Treeline  Temperature controlled  Dating wood from tree above current treeline  Arctic brown paleosols beneath recent Spodosols  Lower Treeline  Moisture controlled  Packrat Middens

Krummholz  Prostrate stunted vegetation  Protected by snow pack  Can grow above present treeline  Technically a different genetic species of a plant that has stunted growth, but broadly used for environmentally stunted trees

Flagged leaders standing out from a Krummholz matt

©Tom Kloster 2001:

Problems with Treeline Studies  Incomplete fossil record (highest elevation trees may not have been found)  Elevation of mountain summits restrict how high treeline could be recorded  Present treeline is hard to determine  Disturbances can affect tree line (fire, grazing, avalanches, wind abrasion, insects)  Lag time in response to climate changes  Advance faster than retreat  Treeline may be affected by isostatic uplift

Treeline Fluctuations, Sweden Dahl and Nesje 1996

Vegetation Zones with Elevation

Changes in Major Vegetation Zones for 22,000 years in Nevada

Packrats (Neotoma)  First used in Quaternary Paleoecology introduced by Phillip Wells (Wells and Jorgensen, 1964), a zoologist doing vegetation reconnaissance on the Nevada Test Site.  Collect all vegetation around the midden  Preserved by amberat (urine)  Also bring in pollen

Packrat Midden Locations

Davis:

Packrat Midden

Packrat Midden from University of Arizona (has Giant Sloth Bones)

Macrofossils and Pollen from Packrat Middens Davis:

Problems with Packrats  Collected material may not represent a random representation of surrounding environment  Different species have different preferences  Discontinuous deposits  Bioturbation

Creosote Distribution From Packrat Middens Davis:

Insect Studies  Organisms used  Coleoptera (Beetles) most common  Diptera (Flies)  Hymenoptera (Wasps and Ants)  Found in sedimentary deposits such as lake beds or peat  Based on exoskeleton morphology  Little lag in assemblage changes

Insects  Study of late Quaternary beetle faunas began with  J.V. Matthews (1975) North American  G.R. Coope's (1977) study of British deposits  S.A. Elias (1985) western U.S.  Production  More species of beetles than of all other animals.  Dispersal  Taphonomy poorly studied, but fossils are interpreted as local, however, many beetles can fly and their remains are present in streams.  Preservation  Beetle carapaces are the most resistant of all insect fossils. Their elytrae (chitinous wing covers) are particularly abundant, heads and legs also common.  Identification  Beetles are probably the best studied insect group (taxonomically), and their preserved remains useful in identification

Beetle Morphology

Reconstructed Paleotemperature Based on Insect Remains, UK

Mutual Climate Range

Chironomid Percentage Diagram