What is the Holocene? The last 11,800 years Oxygen Isotope Stage - PowerPoint PPT Presentation

What is the Holocene? • The last 11,800 years • Oxygen Isotope Stage 1 (warm interglacial) • Clear indications of human impact on the environment - Development of agriculture/urbanisation

What is the Quaternary? • Since at least the nineteenth century, different groups of geologists have used conflicting terms to describe the recent past. Some simply describe the past 23 million years as the Neogene period. But others invoke an extra period — the Quaternary — which follows the Neogene and began around 2 million years ago. • The last 2.588 million years

The lead up to the Holocene

Climate and the Holocene

Abrupt Climate Change Events

Case Studies…. Kuk Swamp Lake Euramoo Bega Swamp

Case Study…. Tropical Rain Forest of Northern Australia • The rainforest vegetation includes mixtures with sclerophyll tree species that occur as emergent and co-dominant species in the canopy. Fringing the rainforests are areas of tall, open forest and tall, medium and low woodland. • The palaeoecological record is from Lake Euramoo, a small crater lake at 730 masl near the boundary of sub-montane rainforest and schlerophyll woodland.

Tropical Rain Forest of Northern Australia Lake Euramoo S M S D M N R R A E L E P D P S O O S O O N W M I G Y N L G L y A ) e P Y t y D i T T s g t B H i S S E n n s P r C e a r E E y O d e h U R R v l C R l a D i O O a d S c E O o f o F F ( o L B s c e N N e R e Depth H R r e a a g I I n T t A A C E l h a A a o N R R S H C R P m Z I 16 0 Eu-5 17 1 18 2 Eu-4 3 19 20 4 5 21 6 Eu-3 7 22 8 9 10 23 Eu-2 12 • 22-15ka: 14 16 • Cold/Dry Schlerophyll Woodland 18 24 Eu-1 20 22 • Low turnover

Tropical Rain Forest of Northern Australia Lake Euramoo S M S D M N R R A E L E P D P S O O S O O N W M I G Y N L G L y A ) e P Y t y D i T T s g t B H i S S E n n s P r C e a r E E y O d e h U R R v l C R l a D i O O a d S c E O o f o F F ( o L B s c e N N e R e Depth H R r e a a g I I n T t A A C E l h a A a o N R R S H C R P m Z I 16 0 Eu-5 17 1 18 2 Eu-4 3 19 20 4 5 21 6 Eu-3 7 • 15-8.3ka: 22 8 • Mosiac Schlerophyll Woodland- 9 10 Sub-Montane Rain Forest 23 Eu-2 12 14 • Punctuated high turnover 16 18 24 Eu-1 episodes 20 22

Tropical Rain Forest of Northern Australia Lake Euramoo S M S D M N R R A E L E P D P S O O S O O N W M I G Y N L G L y A ) e P Y t y D i T T s g t B H i S S E n n s P r C e a r E E y O d e h U R R v l C R l a D i O O a d S c E O o f o F F ( o L B s c e N N e R e Depth H R r e a a g I I n T t A A C E l h a A a o N R R S H C R P m Z I 16 0 Eu-5 17 1 18 2 Eu-4 3 19 20 4 5 • 8.3-4.8ka : 21 6 • Warm Sub-Montane Rain Forest Eu-3 7 • Very low turnover 22 8 9 10 23 Eu-2 12 14 16 18 24 Eu-1 20 22

Tropical Rain Forest of Northern Australia Lake Euramoo S M S D M N R R A E L E P D P S O O S O O N W M I G Y N L G L y A ) e P Y t y D i T T s g t B H i S S E n n s P r C e a r E E y O d e h U R R v l C R l a D i O O a d S c E O o f o F F ( o L B s c e N N e R e Depth H R r e a a g I I n T t A A C E l h a A a o N R R S H C R P m Z I 16 0 Eu-5 17 • 4.8-0.12ka : 1 • Cool/Dry Sub-Montane Rain 18 2 Forest with increasing turnover Eu-4 3 • Loss of long-lived trees 19 (eg Agathis ) 20 4 5 21 6 Eu-3 7 22 8 9 10 23 Eu-2 12 14 16 18 24 Eu-1 20 22

Tropical Rain Forest of Northern Australia Lake Euramoo S M S D M N R R A E L E P D P S O O S O O N W M I G Y N L G L y A ) e P Y t y D i T T s g t B H i S S E n n s P r C e a r E E y O d e h U R R v l C R l a D i O O a d S c E O o f o F F ( o L B s c e N N e R e Depth H R r e a a g I I n T t A A C E l h a A a o N R R S H C R P m Z • Last 120 years : I 16 0 • Cold/Dry Sub-Montane Eu-5 Rain Forest with High Turnover 17 1 • Invasion of exotic plants 18 2 Eu-4 3 19 20 4 5 21 6 Eu-3 7 22 8 9 10 23 Eu-2 12 14 16 18 24 Eu-1 20 22

Age (years BP) 10000 12000 11000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 Bega Swamp 1025 m, Southern New South Wales Podo Pomaderris carpus Eucalyptus type 1 Eucalyptus cf. pauciflora Eucalyptus type 2 Acacia Callitris Casuarina Epacr is type Kunzea type Le ptospermum Monolete Ble chnum Poaceae Fe rn spores Tu bulifl o Char coal ra e (>5 m) µ

Implications of long-term increases in disturbance for rain forest ecosystems • Increase disturbance frequency post 5000 yr BP ⇒ higher turnover rates ⇒ loss of large long-lived trees ⇒ internal fragmentation alters species composition ⇒ greater opportunity for invasion by fast growing plants (eg. gap-dependent species, weeds and lianas) Phillips et al . (2002) Nature 418 , 770-774

Origins of Agriculture Origins of Agriculture Centres of Centres of origin origin of food of food production production • Archaeological and • Archaeological and palaeoecological palaeoecological studies have revealed at least studies have revealed at least 10 independent centres of food production. 10 independent centres of food production. • New Guinea has been considered a “secondary centre, where • New Guinea has been considered a “secondary centre, where agricultural development was derived from or triggered by the arrival rival agricultural development was derived from or triggered by the ar of domesticates from Southeast Asia. of domesticates from Southeast Asia.

Two Hypotheses 1. DISPERSAL DISPERSAL : Domesticated plants (taro, bananas, sago, sugarcane) : Domesticated plants (taro, bananas, sago, sugarcane) 1. and animals (pig, chicken) were dispersed from Southeast Asia as part part and animals (pig, chicken) were dispersed from Southeast Asia as of the migration of “Austronesian of the migration of “ Austronesian” speakers around 4000 yr BP into the ” speakers around 4000 yr BP into the Pacific and Indian Oceans. Pacific and Indian Oceans.

Two Hypotheses 2. INDEPENDENT INVENTION: INDEPENDENT INVENTION: 2. New Guinea was a primary centre for agricultural development and New Guinea was a primary centre for agricultural development and plant domestication prior to any known influence from Southeast Asia east Asia plant domestication prior to any known influence from South (prior to 4000 yr BP). (prior to 4000 yr BP).

The Highland Valleys The Highland Valleys The highland valleys are found The highland valleys are found along the main cordillera of inland along the main cordillera of inland New Guinea between an altitude of New Guinea between an altitude of 1200 – – 2000 m asl asl. Intensive . Intensive 1200 2000 m Kuk Swamp Swamp Kuk agriculture supports a population agriculture supports a population h of over 3 million people there of over 3 million people there today. today.

Archaeological Evidence for Archaeological Evidence for Agriculture: Kuk Kuk Swamp Swamp Agriculture: • Plant exploitation and some cultivation occurred on the wetland Plant exploitation and some cultivation occurred on the wetland • margin at 10200 cal BP (Phase I) margin at 10200 cal BP (Phase I) • Mounding cultivation began by 7000 cal BP (Phase II) Mounding cultivation began by 7000 cal BP (Phase II) • • Ditched cultivation began by 4350 cal yr BP (Phase III). Ditched cultivation began by 4350 cal yr BP (Phase III). • I Phase Phase II III IV V&VI Cal Cal kyr BP BP 10 9 8 7 6 5 4 3 2 1 0 kyr

Anthropogenic Indicators in Anthropogenic Indicators in New Guinea New Guinea

Kuk Swamp Pollen Record: Swamp Pollen Record: Kuk LGM- -Present Present LGM Calibrated Radiocarbon Date BP (x1000) 2.8-4.8 9.9-10.2 2.5 6.5-7.0 7.4 9.9 >15 20 Musaceae (% phytolith sum) 15 Eumusa Musa ingens Ensete 10 5 Pollen and Spores (% total sum) 80 60 40 20 Phase 3 Phase 2 Grey-brown clay Phase 1 Late Black clay Pleistocene peat Archaeostratigraphy

Non- -Synchronous Forest Synchronous Forest Non Clearance in the Mid- -Late Holocene Late Holocene Clearance in the Mid • An increased focus on wetland cultivation during the mid An increased focus on wetland cultivation during the mid- -late Holocene led late Holocene led • to rapid clearance of forests, particularly swamp forest environments. to rapid clearance of forests, particularly swamp forest enviro nments. Swamp Myrtaceae Arboreal Pollen Baliem Telefomin Tari 8ka 7ka 3ka 7ka 4ka Nurenk 2ka 100 60 h % 50 Kainantu h 0 0 h h h 12 10 8 6 0 12 10 8 6 0 4 2 4 2 h Age (10 yr B.P 3 .) Age (10 yr B.P 3 .) • Forest decline is not synchronous across the highlands. • Forest decline is not synchronous across the highlands.