Quaternary EnvironmentsQuaternary EnvironmentsQuaternary EcologyQuaternary Ecology

Paleoecological StudiesPaleoecological Studies

Cannot establish experiments and Cannot establish experiments and replicate themreplicate them

Look for evidence of events that occurred Look for evidence of events that occurred through time and use these “natural through time and use these “natural experiments” of the past to generate experiments” of the past to generate hypotheseshypotheses

Substitution of Space for TimeSubstitution of Space for Time

Pollen AnalysisPollen Analysis

One of our best records of vegetation One of our best records of vegetation assemblages assemblages

Allows us to test hypothesesAllows us to test hypotheses

Venn Diagrams of Analogue Venn Diagrams of Analogue SituationsSituations

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

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.

Scale IssuesScale Issues

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

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

Environmental Disturbance Regimes, Biotic Environmental Disturbance Regimes, Biotic Responses, and Vegetation Patterns Viewed in the Responses, and Vegetation Patterns Viewed in the

Context of Four Space-Time Domains.Context of Four Space-Time Domains.

SuccessionSuccession

Clements’ ViewClements’ View Plant community associations that remain Plant community associations that remain

intactintact Gleason’s ViewGleason’s View

Species are distributed individualistically Species are distributed individualistically according to their tolerancesaccording to their tolerances

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

Gradient Studies and Elevational Effects During Gradient Studies and Elevational Effects During the Last Glacial Maximumthe Last Glacial Maximum

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

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

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

Individualistic ResponseIndividualistic Response

Cold HardinessCold Hardiness Response to DisturbancesResponse to Disturbances

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

Deciduous Forest.Deciduous Forest.

Cold Hardiness Zone Map.Cold Hardiness Zone Map.

Region A less than -40 ºCRegion B may reach -40 ºCRegion C does not reach -40 ºC

DisturbancesDisturbances FireFire

Itasca State Park, Northwestern MinnesotaItasca State Park, Northwestern Minnesota Western Margin of the Hemlock-White Pine-Northern Western Margin of the Hemlock-White Pine-Northern

Hardwood Forest RegionHardwood Forest Region Changing Fire Frequency 33 or 44 years to 80-90 yearsChanging Fire Frequency 33 or 44 years to 80-90 years

ClimateClimate Controls VegetationControls Vegetation Feedbacks to FireFeedbacks to Fire

Insect OutbreaksInsect Outbreaks

Changes in Fire Frequency in Northwestern Minnesota Changes in Fire Frequency in Northwestern Minnesota reflected in a Shift from a 44-year Cycle to an 88-year reflected in a Shift from a 44-year Cycle to an 88-year

Cycle (from Clark 1988)Cycle (from Clark 1988)

Distinct Vegetation Types Due to Critical Climatic Distinct Vegetation Types Due to Critical Climatic ThresholdsThresholds

Vegetation Dependence on Climatic Factors Controlling Vegetation Dependence on Climatic Factors Controlling Final Stable Vegetation StateFinal Stable Vegetation State

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

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

Forest ModelsForest Models

FORETFORETJABOWAJABOWA

Human EvolutionHuman Evolution

North American Land Mammal Ages

Rancholabrean Bison, Mammuthus, Equus, Modern taxa 0 - 0.5 Ma

IrvingtonianMammuthus, Equus, Euceratherium, Smilodon, Mocrotus

0.5 - 1.8 Ma

BlancanEquus, Nannippus phelgon, Stegomastodon, Borophagus diversidens, Trigonictis, Nekrolagus, Procastoroides, Sigmodon.

1.8 - 4.5 Ma

HemphillianMachairodus, Agriotherium, Plesiogulo, Osteoborus, Osbornoceros, Prosthennops, Pliohipppus, Astrohippus

4.5 - 8.2 Ma

Megafaunal ExtinctionMegafaunal Extinction

Pleistocene ExtinctionsPleistocene Extinctions

Radiocarbon-Dated MegafaunaRadiocarbon-Dated Megafauna

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

Worldwide Megafaunal ExtinctionsWorldwide Megafaunal Extinctions

Land Bridges During Land Bridges During the Last Glacial the Last Glacial MaximumMaximum

Human Expansion Human Expansion into the Americasinto the Americas

Marine OverkillMarine Overkill