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
• Tribal Culture
Reconstruction
– Archaeological data
sources
– Linguistic divergence
– DNA/genetic traits
– Cultural traits,
technologies, and
socio-economic
systems
• Historical
Reconstruction
– Marine Fossil/Isotopic
Record
– Tree Rings, Climate
and Fire Regimes
– Neotoma (Pack Rat)
Nests
– Pollen and Microfossil
Records
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 socioeconomic [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
Nino
West 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:
Kennett et al. 2007
Southern Calif-Channel Islands: Increased resource utilization,
cultural technologies, and intensive resources exploitation
Mid-Holocene Adaptive
Responses and
Specialization: Southern
Calif. (continued).
Kennett et al. 2007
• 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
Late Holocene: PNW Plateau [to/from Coast]
Glacial advance, expanded forest cover,
greater salmon
Bow/Arrows
To Calif.?
Medieval
C.A.
Prentiss et al. 2006: Archaeology of NW North America
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
techniques
Byram 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 PNWCalif. 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. 800900)
• 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
California
Plateau
PNW Coast
Overview of Evidence
• Archaeological
evidence integrated
with paleo-science
data provides spatial
and temporal phases
in which to
understand humanenvironment
relationships
• Climate influences biophysical processes at
various scales
– Productivity, Hydrology
and Fire Regimes
– Humans adapted to and
were influenced by
climate’s influence on
natural resources
Descargar

Document