Archaeological evidence for climate change impacts on people and natural

resources of the PNW [and Calif.!]• Frank K. Lake

– Ph.D. 2007, OSU– USFS PSW Research

Ecologist– Tribal Ethno-ecology– Fuels, Fire, and Fisheries

Management*Program on Climate Change: University of Washington/Friday Harbor Laboratory- Thanks!

Evidence: Sources of data used• Archaeological

– Lithic: Hunting and food processing artifacts

– Human, animal, and plant remains: AMS 14 C ages

– Establishment and occupation site chronologies

– Climate and natural resources conditions

Prentiss et al. 2006: Archaeology of NW North America

Climatic Processes and Pattern Impacts on Tribal Cultures of the PNW

• Historical Reconstruction– Marine Fossil/Isotopic

Record– Tree Rings, Climate

and Fire Regimes– Neotoma (Pack Rat)

Nests– Pollen and Microfossil

Records

• Tribal Culture Reconstruction– Archaeological data

sources– Linguistic divergence– DNA/genetic traits– Cultural traits,

technologies, and socio-economic systems

Subsistence Intensification: • A process of change in subsistence behavior

whereby and increase in energetic return to land area or labor input required to acquire resources to meet socio-economic [survival] needs– Intensification can be adaptive or maladaptive– Labor correlated with technological

innovations or socio-economic organization• TI: Methods to extend intra-annual utility of

subsistence resources- “Get more per time of year or season” with labor available

Tribal Cultures, Natural Resources and Climate

• Cultural Complexity– Resource

specialization

• Bio-physical Productivity– Climate influenced

resource availability

Scale of Major Climate Change Periods Affecting Tribal Cultures• Last Glacial Maximum• Younger Dryas• (Middle) Holocene

Maximum• Medieval Climatic

Anomaly• Little Ice Age• PNA/PDO, La Nina/El

NinoWest et al. 2007 of Woolfenden 1996

PNW-Calif. Climate Change and Tribal Cultural Adaptive Responses

• Demographic shifts/migrations to more productive environments

• Changes in cultural technologies and socio-economic systems

• Cross-cultural conflicts and/or diversification

• Environmental changes and subsequent human responses

“…it was not climate that prehistoric populations were interacting with per se, but the effects of climate on the biophysical environment” (West et. a. 2007).

Factors limiting the evidence of first peoples and development of tribal cultures in the

PNW and Calif. • Glaciation [Open coast?]• Sea level [When and where?]• Marine and precipitation

erosional forces • Landscape/Vegetation change• Site/area conditions at time of

settlement and occupation• Site preservation (acidic soils

and organic material decomposition)

Palaeocoastal Settlement:

13,00-11,500 cal BP• Evidence for

each major region of the Pacific coast– Northwest

Coast– Alta California – Baja California

Erlandson et al. 2008: Life on the edge…

Mid-Holocene: 5800 cal yr BP• Major changes in PNW

cultures observed• Sea level stabilization

– Southern PNW/Calif.• Increased subsistence

specialization and technologies

• Increased abundance of “critical” natural resources: Fisheries

• Cultural transition circa 4850 cal yr BP Moss et al. 2008: Mid Holocene Culture and Climate

on the Northwest Coast of North America

Mid-Holocene Adaptive Responses and Specialization:

Southern Calif-Channel Islands: Increased resource utilization, cultural technologies, and intensive resources exploitation

Kennett et al. 2007

Mid-Holocene Adaptive Responses and

Specialization: Southern Calif. (continued).

• Sea temperatures affected ocean and coastal vegetation productivity

• Different species of shellfish exploited [or affected by SST??]

• Nitrogen and carbon isotopic composition of human bones support diversified marine and terrestrial adaptation and resource utilization

• Data allow for a comparison of prehistoric human island and mainland adaptive strategies

• DNA-human genetics distinguish two cultural/linguistic groups for northern, southern islands, and main land

Kennett et al. 2007

Late Holocene: PNW Plateau [to/from Coast]

Prentiss et al. 2006: Archaeology of NW North America

Bow/Arrows

Medieval C.A.

Glacial advance, expanded forest cover, greater salmon

To Calif.?

Mid to Late Holocene Climate change impacts to southern PNW hydrology and fisheries resources

• Sea level stabilization– Estuaries and river access– Precipitation regimes and basin

hydrology– Changes in sea surface

temperatures and productivity– Salmonid, other fish species

distribution and run times• Tribal harvest technologies

– Tidal and in-river weirs– Specialization of capture/harvest

techniquesByram 2002: Oregon Coast Fish Weirs

Columbia River: Paleo-hydrology and Salmon Resource Availability [Specialization or Climate?]

Fluctuations of salmon abundance correlate with regional precipitation and hydrology phases.

Medieval Climatic Anomaly: AD 800-1350 • Drought conditions in the

Pacific West/Great Basin• Abrupt declines in

productivity caused by repeated and prolonged droughts

• Shortages of food and water-reduced productivity

• Increased warfare/stress among groups

• Forced migration to more productive habitats by small groups Jones et al. 199: Settlement disruption-Big

Sur Cal coastal village/sites

Central Calif.: Late Holocene with Medieval Climatic Anomaly

Droughts with periods of cool/wet: Cool ocean temperatures and arid inland environments AD 450-1350 [Jones and Schwitall 2008]

Linguistic Prehistory and Evidence: Cultural Demographic Shifts in Response to Climate

Change• Penutian language family and

related tribal groups the most widely established in the PNW and Calif. circa 1850 AD.

• Penutian dialects on the Columbia Plateau/Northern Great Basin having a series of coastward migrations west of the Cascades and Sierra Nevada mountains

• Medieval Climatic Anomaly– Interior warming and drying– Loss of productive wetlands– Forced movement westward to more

productive maritime influenced resources.

Golla 2007

Linguistic and Archeological of PNW-Calif. Culture Migrations

• Circa 1,300 BP Algic groups moving from Columbia Plateau west to Puget Sound and NW Calif. (A.D. 100 and 700)

• Athabaskans soon followed from SW Alaska south in to PNW/NW Calif. (A.D. 800-900)

• North Cal. Penutian migration and establishment A.D. 500-600 (beginning circa 1,200 BP) Whitaker et. al. 2000: Obsidian

sources and trade

Human DNA: Evidence of Cultural Migrations and Settlement Patterns in Response to Climate

• Genetic data indicates similarities and differences among tribes which appeared otherwise similar based on cultural traits at the Late Holocene/Little Ice Age

• DNA is compared with linguistic data provide insights to migration and establishment chronologies

Consensus tree of western NA populations based on genetic

distances constructed with mtDNA haplogroup frequencies

AD 1400-1700-Little Ice Age: Cultural Establishment and

Specialization• Similar cultural

subsistence practices and socio-economies

• Diversification of labor based on classes or status

• Shared (formerly borrowed) cultural traits, but different languages and genetic origins

PNW Coast

Plateau

California

Overview of Evidence• Climate influences bio-

physical processes at various scales– Productivity, Hydrology

and Fire Regimes– Humans adapted to and

were influenced by climate’s influence on natural resources

• Archaeological evidence integrated with paleo-science data provides spatial and temporal phases in which to understand human-environment relationships