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Environmental change and cultural response in the Pacific islands over the last millennium. A view from the margins Simon Haberle, Atholl Anderson, Geoff Hope, Matiu Prebble, Nick Porch, Iona Flett, and Michael Gagan Climates for Change in the Pacific MWP LIA Key Issues • Is the “AD1300 Event” significant enough to impact on human society in the Pacific region? • Need to understand the nature and extent of impact of climate change and variability on the environment through time - local to regional • Need to be able to distinguish in the biotic record processes associated with human activity from natural processes - requires records with temporal and spatial resolution comparable to processes being examined (~decadal) Climates for Change in the Pacific Hypothesis I Colonisation Hypothesis II Population growth Reduced mobility HUMAN IMPACT Settlement Agricultural expansion Resource depletion Territoriality Monumental structures CLIMATE CHANGE Climates for Change in the Pacific Pacific archaeology-palaeoecology reveals a set of cultural changes during the Holocene that may have been linked to the influence of climate change (Haberle & David 2004, Quaternary International.) Palau Galapagos Islands Papua New Guinea Atherton Wet Tropics Rapa Juan Fernandez Arch. Criteria for identifying human response to “AD 1300 Event” Criteria Climate proxies record shift around AD 1300 + 50 Chronology + 50yr accuracy Unprecedented natural system change following Event Cultural change identified soon (<300 yr) after Event No comparable cultural change precedes Event Most parsimonious explanation Cultural trend (Cu) or Climate Event (Cl) A B C D E F Climate setting Crossequatorial flow south Jan ITCZ SE Trades/ Monsoon Climate setting Jun ITCZ Crossequatorial flow north SE Trades El Niño and Fires Dry The most intense fires took place in 1997- 1998 in association with the strongest El Niño event of the 20th century ITCZ Palau al ys is Palau earthworks An Ngerc hau Core 14 C ed nd et re D M M 14 ag C ne t sa ic m pl es su sc ep t or re ib i lit sp o y (k ) nd en ce (a dd itional a nalysis b y Ha b erle a nd Pre bb le ) an gr es ov s ee Tr d an r sh ub s H b er s C to yr m er sp C Depth cm 10 0 5 0 10 20 30 40 50 60 70 80 90 sp r ha . co n co al c. (× 10 mm 2 /cm 2) (% ) 0 a 5 0 5 10 15 20 Pollen Zone 440+40 N-3 100 200 2150+40 2580+60 2460+60 2850+60 1370+40 Monuments 1800-1500 BP Deforestation 2800-2500 BP Colonisation 3300-3000 BP 3840+90 N-2 • Widespread deforestation visible ~200 yr after colonisation 5200+60 300 400 4010+50 3900+60 3850+60 N-1 • Monumental earthworks develop >1000 yr after colonisation 500 4010+60 600 Peaty silt loam Gleyed Clay Peat Organic silt loam (Po llen da ta from Athe ns a nd Ward 2002) • Move toward social complexity and longdistance interaction in last 1500 years and particularly from 600 BP. Took a different form in each major island group. Highlands of Papua New Guinea The highland valleys are found along the main cordillera of inland New Guinea between an altitude of 1200 – 2000 m asl. Intensive agriculture supports a population of over 3 million people there today. 7000 yr of independent agricultural development involving innovation in crop domestication, fertilisation and hydrological management. Casuarina oligodon is a nitrogen fixing tree that is commonly planted throughout the highlands and used for multiple purposes (house, fencing material, crop shade, fallow tree). Highlands of Papua New Guinea Casuarina h h h h h h Baliem h Palaeoecological records showing Casuarina rise after 1500 yr BP Telefomin •Loss of local forest cover led to adoption of silvicultural techniques to compensate for loss of forest resources and depleted nitrogen levels. Tari Nurenk 8 •Began 1500 yr BP and proliferated after 600 yr BP 4 Kainantu 0 12 10 8 6 3 4 Age (10 yr B.P.) 2 0 Wet Tropics of NE Australia •Aboriginal occupation in the rainforest required knowledge of toxic plant processing and management of open patches Occupation intensified around 700 yr BP Wet Tropics of NE Australia Macro-charcoal Accum. Rate Charcoal record at Lake Euramoo reflects rainforest burning and disturbance LIA 600 1997 x x ‘86 500 ‘58 ‘42 ’10’-02 x x MWP 1685 xxxx xx 1380 1190-1210 x 1890 x xxx 1000-950 AD x xx • Greater burning/disturbnace during MWP and transition 400 300 • Low burning/disturbance during wet LIA 200 Threshold Mean 100 0 Depth (cm) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Rapa Tukou • Archaeological record spans ~800 yr BP (Kennett et al, 2006) • Monumental structures commence around AD1450-1500, some 250 yr after first colonisation, and become widespread by AD1750 Rapa Tukou pollen record Monuments 450-200 BP Deforestation 700-600 BP Colonisation 800 BP Eastern Pacific Islands Project Stepping stones or barriers for human migration? Isla Coco Galapagos Islands Desventuradas Islands Easter Island Chicken brought to Chilean coast around 620 yr ago (Storey et al. 2007) Juan Fernandez Islands Isla Santa Maria Isla Mocha El Arenal Juan Fernandez Archipelago •No evidence for pre-Colombian occupation of the Juan Fernandez Arch. Juan Fernandez Archipelago 550 BP 1200 Altitude (m) 1000 Inocentes 500 BP 800 Tree line 600 La Piña 7900 BP 400 200 0 3600 BP Plazoleta del Yunque 9300 BP Ch ar co al 1400 BP Fo re st He rb s Range of Historic Variability (RHV) analysis suggests unprecedented (for last 9000 yrs) ecosystem changes have occurred only since European settlement of the islands. RHV (PCA axis 1&2) ns r Fe RHV (PCA axis 1&2) Galapagos Islands Archaeology Palaeoecology •No evidence for pre-Colombian occupation of the Galapagos Is. Galapagos Islands Quinine Bog 1200 Calendar years BP -60 1000 Fern-sedge 600 400 200 zone 50 100 1440 1940 y = 0.5036x + 28.561 y = 0.1429x + 53.999 150 200 y = 0.1427x + 52.668 250 300 350 0 940 0 De pth (cm) 800 440 400 210Pb Individually calibrated 14C WMD cal 60-80 WMD cal 80-360 Linear (210Pb trend) Linear (WMD cal 80-360) Linear (WMD cal 60-80) 2440 Galapagos Islands 1200 1000 Fern-sedge 800 zone 600 400 200 0 Laguna Espumilla Laguna rage 0yrs e 0 v 1 a Age ev ents/ Espumilla ax is 1 v from a A ion de XRF chBP) C les o P c (cal c i t t a F r a c a l c lp Pal mifi 1) E XR Lag SA(PCA Huaxis Tot a Laguna Espumilla XRF analysis 0 0 100 100 200 300 200 300 400 400 500 500 600 700 600 700 800 800 900 900 1000 1100 1000 1100 1200 1200 1300 1300 1400 1500 1400 1500 1600 1600 1700 1700 1800 1900 1800 1900 2000 2000 2100 2100 2200 2300 2200 2300 2400 2400 0 8 16 24 0-70 yrs 70-575 yrs 575-2450 yrs 32 -1.0 0.0 1.00.1 -0.3 2.0 -0.7 -1.1 0 0.5 500 1000 1500 ) ) ded Laguna ded n n e e r 1 e tr det (Espumilla xis on (d a n s Age catio ten C Aificati P n P i i f XRFRF - Hum mi edXRF r uBP) (cal a H X at h illa e 1) eat illa axis coc P (PCA m P m a u u c Q p Q ll p Laguna Espumilla XRF analysis YEARS AD SC YEARS AD Es 2000 2000 1800 1800 SC Pa Es Human Occupation 1600 1600 1400 1400 1200 1200 1000 1000 800 Natural Processes 800 0.7 0.2 -0.3 -0.8-1.0 0.0 0.7 1.0 0.2 2.0 -0.3 0 -0.8 50 10 0 15 0 20 0 1.0 25 0 -1.0 0.0 2. Climates for Change in the Eastern Pacific Laguna Laguna Laguna Climate ge Quinine Bog Charred ge e yrs scale a l a r r 0 a e e c 0 v s v a rey Pallcacocha Humification Asteraceae Pallcacocha m rey ts/1 hEspumilla g g om a o n r r 3 3 is 1 Zones e a a f f x v h a e v v m c m c e e c c a o o A d d c s s Particles (events/100yr) XRF PC coch Pallcac t ion Age ti cle ficat ion allca ti cle (reda intensity) a F r r a c P a a l c R l i p p a f a n l P agu n mi (cal yr b2000) mi --- dry) Tot al E X axis 1) Tot a Hu(wet Lagu Lag SA(PCA L 0 0 100 100 200 300 200 300 400 400 500 600 700 AD 1425 70-575 wet yrs 500 600 700 800 800 900 900 1000 1100 1000 1100 1200 1200 1300 1300 1400 1500 1400 1500 1600 1600 1700 1700 1800 1900 1800 1900 2000 2000 2100 2100 2200 2300 2200 2300 2400 2400 5 0.1 -0.3 -0.7 -1.1 0 0-70 yrs 500 1000 0.5 15000.1 2000 4000 4500 502500 100 3000 150 200 0 4500 8 -0.32500 -0.7 3000 -1.1 03500500 1000 150002000 3500250 4000 dry 575-2450 yrs -1.0200 250 0.0 016 5024100 32 150 1.0 2.0 Climates for Change in the Pacific Laguna Laguna Laguna Euramoo ge Quinine Bog Charred ge e yrs scale a l a r r 0 a e e c 0 v s v a rey Pallcacocha Humification Asteraceae Pallcacocha m rey ts/1 hEspumilla g g om a o n r r 3 3 is 1 Charcoal e a a f f x v h a e v v m c m c e e c c a o o A d c c h s s Particles (events/100yr) XRF PC on d Age ti cle ficat ion allca ti cle (reda intensity) acoc a Pallca F r r c P a a l R l icat i p p a n l P agu n mi --- dry) Tot al E X axis 1) (cal yr b2000) Tot a Hu(wet Lagu Lag SA(PCA L 200 300 400 400 600 700 AD 1425 AD 1380 500 600 700 900 1000 1100 1000 1100 1200 1200 1300 1300 1400 1500 1400 1500 1450 800 900 950 800 1600 1600 1700 70-575 yrs 450 500 AD 280 1700 1800 1900 2000 2000 2100 2100 2200 2300 2200 2300 2400 2400 500 1000 0.5 15000.1 2000 4000 4500 502500 100 3000 150 200 0 4500 8 -0.32500 -0.7 3000 -1.1 03500500 1000 150002000 3500250 4000 1950 1800 1900 0.1 -0.3 -0.7 -1.1 0 0-70 yrs -1.0200 250 0.0 016 5024100 32 150 1.0 2.0 575-2450 yrs 400 200 300 300 100 200 100 -50 0 100 0 0 Criteria for identifying human response to “AD 1300 Event” Criteria A B C D E F Climate proxies record shift around AD 1300 + 50 X X ? X Chronology + 50yr accuracy X X X Unprecedented natural system change following Event X X Cultural change identified soon (<300 yr) after Event ? ? No comparable cultural change precedes Event X X X X X Cu Cu Cl Cl Cu Cl Most parsimonious explanation Cultural trend (Cu) or Climate Event (Cl) Conclusions • Climate change around AD1300 may not be regional nor synchronous across the Pacific • Major change recorded AD1380-1425 in some records from Eastern and Western Pacific islands some >30-80 yr after the AD1300 Event • Some islands (and societies) where more vulnerable than others • Thresholds in societal and ecosystem change may only be breached on some islands (including “circumscribed ecosystems” such as rainforest) • Chronology is critical • Striving for maximum resolution (temporal and spatial) is essential in arguing cause and effect of climate change on human society through time • Developing rigorous hypothesis testing will be required to move the debate forward Age YEARS AD (cal BP) ) Quinine Bog Laguna Laguna Palmyra ed nd e r t Humification Espumilla Pallcacocha coral de is 1 ax n( sity o n A i t n te XRF - PC fica di mi at Pe Hu e ar ch o c llca F XR li la m CQ --- dry) E( spPCA axis 1)P(ared intensity) (Swet u 2000 1800 1600 1400 1200 1000 800 0.7 0.2 -0.3 -0.8-1.0 0.0 1.0 2.0 0 50 100 150 200 250 (d18O) Laguna Pallcacocha (events/100yr) Eastern Pacific Palaeoclimate Laguna Laguna Laguna ge Quinine Bog Charred ge e yrs scale a l a r r 0 a e e c 0 v s v 1 a a y / re Pallcacocha Humification Asteraceae Pallcacocha m rey ts hEspumilla g g om o n Age r r 3 3 is 1 e a a f f x v h a e v v m c m c e e c c a o o A d d c s s (red scale) Particles (events/100yr) XRF PC coch Pallcac t ion (cal BP) parti cle ficat ion allca ti cle a F r a c P a l c R l i a p a f a n l P agu n mi mi --- dry) Tot al E X axis 1) Tot a Hu(wet Lagu Lag SA(PCA L 0 0 100 100 200 300 200 300 400 400 500 600 700 AD 1425 70-575 wet yrs 500 600 700 800 800 900 900 1000 1100 1000 1100 1200 1200 1300 1300 1400 1500 1400 1500 1600 1600 1700 1700 1800 1900 1800 1900 2000 2000 2100 2100 2200 2300 2200 2300 2400 2400 5 0.1 -0.3 -0.7 -1.1 0 0-70 yrs 500 1000 0.5 15000.1 2000 4000 4500 502500 100 3000 150 200 0 4500 8 -0.32500 -0.7 3000 -1.1 03500500 1000 150002000 3500250 4000 dry 575-2450 yrs -1.0200 250 0.0 016 5024100 32 150 1.0 2.0 200 400 0 4 EL NINO EVENTS 1000 YR NUMBER ARCHAEOLOGICAL DATES CHARCOAL POLLEN Age (cal yr BP) Wet Tropics of NE Australia 8 0 30 0 500 Intensive occupation 800-600 yr BP 1000 1500 2000 2500 3000 3500 4000 •Aboriginal occupation in the rainforest required knowledge of toxic plant processing and management of open patches 4500 5000 5500 6000 6500 7000 7500 8000 8500 •Occupation intensified around 800-600 yr BP