Australia: Water and Soil Through (Pre) History

1. Australia: Water and Soil Through (Pre) History David Radcliffe University of Georgia

2. Published in 1994 3-part series on Australian TV in 1998 www.abc.net.au/science/future/default.htm Tim Flannery is Director of South Australia Museum

3. Future Eaters • Part One – An Infinity Before Man • Geology and ecology of Australia before man arrived • Part Two – Arrival of the Future Eaters • What happened when the aborigines arrived • Part Three – The Last Wave • What happened when the Europeans arrived

5. Early Geology • Australian continent drifted north as the Earth cooled • Stable climate with very little glaciation • “Did you have a good ice age?” • Did not collide with other continents • Little volcanic activity or mountain building • Resulted in infertile soils • Isolated continent (Galapagos on steroids)

6. www.lonelyplanet.com

7. Uluru www.photoway.com/fr/dest/AUST96_30.html

8. Infertile Soils • Tim Flannery, Taming of the Fire, Australian Broadcast TV • “If you want to understand the history of this continent there's no better place to come than here to Uluru. • The timeless rounded features of the rock show that it hasn't been disturbed for hundreds of millions of years, there's been no volcanoes, no mountain building, no ice age here to rejuvenate this place and as a result the soil here is old, leeched and exhausted. • All that's left really is just sand."

12. El Nino • El Nino Southern Oscillation effect (ENSO) • 2-7 year cycle of drought and rainfall • Australia is the only continent where the overwhelming influence of climate is not an annual cycle

13. Under normal conditions, trade winds pile up warm ocean waters to the west and upwelling occurs to the east – warm wet air rises from eastern Australian Under El Nino conditions, trade winds weaken, warm water moves back east – dry air descends on eastern Australia www.pmel.noaa.gov/tao/elnino

15. Biodiversity • Theory: greatest biodiversity develops in low-resource (water & soil), stable environments • Organisms survive better by cooperating • Enough time for evolution of organisms that find a “niche” • Australia has greater biodiversity than other larger continents • Plant species in Australia: 25,000 • Plant species in Greater Europe: 17,500

16. Niche Ecology Examples • Kangaroo • Koala bear • Banded stilt

17. Kangaroo is world’s largest marsupial Very efficient energy user No other animal this big hops Energy is recaptured in each bound, in the tendons of its legs – like a pogo-stick Each leap pushes its gut back, drawing air into it’s lungs – saving it from using chest muscles to breath Low reproductive rate Female is fertile only during ENSO periods of high rainfall Kangaroo Eastern Grey Kangaroo www.giftlog.com

18. Diet consists entirely of Eucalyptus tree leaves Lives it’s life in these trees Leaves have toxins to discourage foraging animals Very energy efficient Slow moving like a sloth Low rate of reproduction Relatively small brain Brain is one of the greatest energy users of all organs In man, the brain is 2% of weight but uses 17% of energy Koala Bear www.giftlog.com

19. Familiar bird along the coast but never seen to breed March 1989 banded stilts disappeared from usual haunts About 100,000 birds found nesting near Lake Eyre in South Australia Lake was filling to a 15-year high as a result of a period of ENSO rainfall Banded Stilt The Slater Field Guide to Australian Birds

20. www.lonelyplanet.com

22. After hatching, the young were tended by the males Hatchlings left the breeding area and grew quickly on a rich diet of brine shrimp After only 3 weeks the young could fly Only 2 weeks after first eggs were hatched, the female was nesting again Breeding cycle adapted to ENSO Can go a decade without breeding Banded Stilt The Slater Field Guide to Australian Birds

23. Future Eaters • Part One – An Infinity Before Man • Geology and ecology of Australia before man arrived • Part Two – Arrival of the Future Eaters • What happened when the aborigines arrived • Part Three – The Last Wave • What happened when the Europeans arrived

24. Conventional view Primitive civilization Did not develop agriculture or cities Nomadic Few tools Little impact Aborigines

25. Aborigines • Man evolved first in Africa about 2 million years ago and spread to other continents • Coevolved with megafauna species still seen today in Africa • Serengeti Plain (think Lion King) • Predator-prey arms race • Aborigines arrived in Australia about 40,000 years ago • Came over water from Southeast Asia • At that time there were a number of megafauna grazing species in Australia • Recycled nutrients from grasses to soil

26. Diprotodon

27. Megafauna Extinction • Megafauna disappeared from Australia shortly after aborigines arrived • Climate or man? • “The greatest danger that a species faces in a rapidly coevolving ecosystem is the loss of contact with its competitors” • Megafauna had no defenses against man and were wiped out • Without megafauna nutrient cycling broke down and grasses disappeared and replaced by forests and deserts • Short, rich period for aborigines followed by disaster

28. Aborigine Adaptation • Aborigines were the first Future Eaters • Consumed resources more rapidly than they could be replenished • “The story of how the first future eaters recovered from this disaster - is one of humanities greatest triumphs” • Long stable period (40,000 years) after megafauna extinction for aborigines to adapt • Developed complex relationship with ecosystem

29. Aborigine Adaptation • Adapted to make it through the driest periods and take advantage of the wet periods • Did not develop agriculture because it was not sustainable given El Nino climate • Nomadism allowed aborigines to move to water and animals • Used fire to burn forests, recycle nutrients, and provide forage for animals – “fire-stick farming” • Few tools because they had to be mobile • Low population density • Social unit was small tribe consisting of a few families

30. Aborigine Adaptation • Challenge was genetics • How to avoid inbreeding when your social unit is a small tribe • Solution was great tribal meetings during ENSO wet periods • Gathered in areas where food and water available • Marriages arranged between members of different tribes • Elaborate ceremonies renewed bonds between tribes • Oral exchange of information on resources • Religion codified rules and was the knowledge-base passed from generation to generation

31. Revised view Highly evolved civilization Nomads because agriculture was not sustainable Few tools because these reduced mobility Elaborate knowledge of ecosystem embodied in religion Large impact Aborigines

32. Future Eaters • Part One – An Infinity Before Man • Geology and ecology of Australia before man arrived • Part Two – Arrival of the Future Eaters • What happened when the aborigines arrived • Part Three – The Last Wave • What happened when the Europeans arrived

33. Arrival of Europeans • Large number of Europeans first arrived in early 1800’s • Aborigines suffered massive die-offs • English settlers applied European agricultural practices • Extensive cutting of forests for timber and to clear land for agriculture • Led to erosion and loss of native species • Second episode of “future eating” occurred

34. Australia Today • Still trying to adapt to harsh conditions • Extensive irrigation systems have been developed that take water from rivers • Result has been saline soils and rivers and low stream flow • Australia today taking a hard-look at how it manages water resources • Searching for an alternative to the European model of resource management • Aborigine the new model for living with harsh ecosystem?

35. Many parallels with Australia 2 cycles of predator invasions Clovis point Indians European settlers Megafauna & Indian extinction Important differences Resource-rich continent Relatively short history Only now are we reaching our limits (water?) Future Eating in America