By Tim LowNon-fiction Penguin
Where Song Began
In Where Song Began, biologist Tim Low upends historical assumptions about Australia’s central importance in the evolution of the world’s birds. While it was once thought that many Australian birds were of northern hemisphere origins, it’s now known that the opposite is true: more than half the world’s birds – including all its songbirds and parrots, many pigeons and the dodo can be traced back to Australia.
Australian birds are also more likely to be intelligent, aggressive, loud and long-lived, and to live in complex societies – and they’ve profoundly shaped the ecology of the land they inhabit. In this fascinating book, Tim Low seamlessly blends biology, history and narrative flair to tell the story of Australia’s birds, and their relationship with the continent and its inhabitants and it has changed and evolved.
Low quotes a researcher who tells him ‘Australians give too little thought to the unusual birds they live among … they accept them at face value rather than wondering about the forces that brought them to be’. In this unique and ground-breaking book, Low does just that, with all the enthusiasm, wonder and erudition of the passionate expert that he is.
‘Tim Low is as much a natural with words as he is a scholar of the natural world,’ writes Nicolas Rothwell in the Australian. ‘He is caught up in the circle of gifted scientists, ecologists and field workers engaged in reshaping our picture of the Australian environment and the creatures it enfolds.’
Tim Low’s vibrant, vivid and constantly surprising work of natural science turns the world on its head by locating Australia as the origin of the world’s songbirds, profiling them and their habitats with the skill of a born storyteller and the eye of an expert analyst. Australian landscape, he reveals, can only be understood by relation to the continent’s rich ornithological endowment. A book bursting to make the reader look again at the familiar and ponder its uncanniness, lovingly produced and splendidly illustrated.
Of Grass and Fire
By a very large margin, grasses are the world’s most successful plants. A third of all global vegetation is grass-dominated, a figure that rises to one half in Australia. Grasses provide six of the world’s top seven crops, feed our herds and flocks, and surface lawns and parks. Songbirds are the world’s most successful birds, humans the dominant mammal, and grasses are their plant equivalents. (1)
Ask why, out of more than 600 plant families, one should so dominate global production, and an odd idea comes up: grasses thrive on their own destruction. They dominate pastures and wild places by sustaining heavy consumption by animals and fire. They specialise not in protecting themselves against damage but in quickly replacing themselves afterwards. They can do this because they are exceptionally productive, fixing carbon more efficiently than most plants, in leaves that are short-lived and cheap to replenish from growing points kept near the ground. They are the only plants to suit lawns for this reason. (2)
Fire was a partner to their success. Many grasses are helped by and help fire. The idea of flammability as an adaptation was first put by American Robert Mutch in 1970, and it has advanced in journal papers such as ‘Kill Thy Neighbour’ and ‘Are Some Plants Born to Burn?’ Some ecologists insist flammability cannot evolve in plants, but claims that adaptations to fire are really adaptations to grazing and drought miss the point that many plants benefit greatly from fire. (3)
In most fires grasses are the main fuel, providing the continuity flames need. Grasses and eucalypts benefit alike from regular fires destroying their competitors, but trees need occasional fire-free years for their seedlings. A succession of hot grass fires will kill even adult trees, allowing grasses at times to displace rainforests, eucalypts and acacia woodlands. Many grasses thrive on yearly fires, and some can survive two a year. (4)
When fires are stopped, trees often thicken up and suppress grass. In national parks along the east coast, missing out on Indigenous burning and on lightning fires that don’t travel far because roads and farms serve as firebreaks, rainforests are advancing via seeds dropped under eucalypts by birds. Australia would carry far more rainforest (supporting rainforest birds) had grasses never evolved. The area of forest on earth would double were fire switched off, according to modelling by leading biologists, with Africa and South America gaining the most. (5)
Although dinosaurs are never portrayed eating grass, in 2005 Science carried an article about fossil coprolites (dung) showing that late-Cretaceous dinosaurs did just that. All the oldest grass fossils come from Gondwanan lands (although not from Australia), suggesting a southern start for another dominating group. Three rush-like plants in Western Australia – making up one of the least successful of all plant families today (the Ecdeiocoleaceae) – are their closest relatives. (6)
Grasses came to success slowly, advancing in steps. Fossils reveal surges in pollen or charcoal as the planet cooled, dried, and became more seasonal, acquiring monsoon climates in which a wet growing season alternates with a dry burning one. The electrical storms that mark the beginning of monsoons often spark fires over vast areas a week or more before the first rain arrives. (7)
Domination by grasses came at different times on different continents, with Australia, going by fossil pollen and fossil teeth, lagging well behind. Her marsupials were late to evolve the high crowned teeth needed for abrasive grasses and few did so, grassland kangaroos and wombats only appearing a few million years ago. The biggest kangaroo ever, the extinct Procoptodon goliah, ate saltbushes rather than grass, judging by the wear marks found on its teeth. The timing meant that grass birds from Asia could move into grasslands before many indigenous birds had evolved to fill the niches.8
1 Grass statistics – Strömberg (2011). The major grass crops include rice, wheat, maize and sugar-cane.
2 Thrive on destruction – Bond and Midgley (1995); Quick replacement – Chapman (1990), Reproductive Versatility in the Grasses, Cambridge University Press, Cambridge; Growing points – Harvey (2002) The Forgiveness of Nature: The Story of Grass, Vintage, London.
3 Mutch (1970), Bond & Midgley (1995), Zedler (1995) Trends in Ecology and Evolution 10(10): 393-95. Critical evidence for evolved flammability was provided recently by McGlone et al. (2014) New Zealand Journal of Ecology 38(1): 1–11.
4 Grasses the fuel – Murphy et al. (2013); Trees need – Bond et al. (2012) Austral Ecology 37: 678–85.
5 Modelling – Bond et al. (2005).
6 Dinosaurs – Prasad, et al. (2005) Science 310: 1177–79; Gondwanan fossils – Strömberg (2011); Ecdeiocoleaceae – Bremer (2002) Evolution 56(7): 1374–87, Michelangeli et al. (2003) American Journal of Botany 90(1): 93–106.
7 Stages – Jacobs et al. (1999); Electrical storms (=lightning fires) – Russell-Smith et al. (2003), Woinarski & Legge (2013).
8 Australia lagged – Strömberg (2011), Jacobs et al. (1999), Martin (1990) Alcheringa 14 (3): 247-55; Browsers – Johnson & Prideaux (2004) Austral Ecology 29: 553–57; Procoptodon – Prideaux (2009) Proceedings of the National Academy of Sciences of the United States of America 106 (28):11646–50.
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