ReviewA fresh framework for the ecology of arid Australia
Research highlights
► Revised propositions about arid Australia are presented based on research since Stafford Smith and Morton (1990, Journal of Arid Environments 18, 255-278. ► Australian plant life-histories distinctively reflect variable temporal patterns of soil moisture. ► Low phosphorus levels favour plants producing a relative excess of carbohydrate, leading to fire-proneness and abundant detritivores. ► Irregular fluctuations in production due to variable rainfall encourage consumers with opportunistic life-histories.
Introduction
Ecological research in arid Australia has particular significance. The major environmental themes that are writ large in Australian deserts – soil infertility and highly variable rainfall – are actually characteristic of the continent as a whole. Consequently, the expressions of these two features across Australia have produced exemplar ecosystems and processes that have deeply informed much global ecological synthesis (e.g. Andrewartha and Birch, 1984, Krebs, 2008, Orians and Milewski, 2007, Pianka and Vitt, 2003, White, 2005). The North American and Mediterranean arid zones, from which the bulk of the scientific literature comes, tend to have relatively predictable rainfall and higher soil fertility. Australian deserts, along with those of South America and Southern Africa, provide a valuable counterpoint.
Stafford Smith and Morton (1990) framed ideas about arid Australian ecosystems in a set of inter-linked ‘propositions’. At the time, evidence for their 16 propositions varied from strong to slight. Twenty years later, the present paper revisits those propositions to consider whether new knowledge necessitates revision or rejection of them, to identify where fresh understanding suggests a new proposition and, where research has not yet confirmed or rejected a proposition, to suggest critical tests.
Section snippets
Background
Overall, three gaps are evident in the ideas underpinning Stafford Smith and Morton (1990). Firstly, the role of deep time in forming the Australian deserts of today was hardly mentioned. As a result many particularities of the Australian biota – such as the domination of marsupials among mammals and of Myrtaceae and Mimosaceae among woody plants – were not sufficiently emphasised. In hindsight, the original text tends to read as if Australian deserts had inevitably arrived at the present point
Physical history
Australia’s tectonic stability relative to other continents has strongly influenced its deserts; the regolith is often an ancient inheritance from the Tertiary or earlier (Pillans, 2007). In some places Australian desert soils have also developed over relatively long time periods, but this does not mean that they have stopped changing, as exemplified by continuing emergence of features such as carbonate horizons. Cracking clays (vertisols) are prominent, as are strongly weathered red earths
Evolutionary history
Eucalyptus and Acacia rose to prominence in the Miocene as drying and burning encouraged development of sclerophyllous woodlands. Chenopod shrublands and grasslands developed during the early Pliocene. Drier glacial phases of the Pleistocene must have forced many plant species into refugia, after which expansion by survivors occurred during interglacials (Martin, 2006). Consequently, species arose most often from nearby coastal localities, rather than by speciation within a specifically
Evolutionary history
Among Australian mammals, marsupials radiated from 50 M years BP; bats are of similar antiquity, but rodents arrived from Asia only 6 M years BP (Merrick et al., 2006). Birds are largely of Gondwanan stock (e.g. parrots and honeyeaters), with admixed descendants of Asian immigrants from the late Tertiary; the deserts contain a moderate number of endemic species (Schodde, 2006). Reptiles are a mixture of Gondwanan lineages and northern arrivals in the Miocene (Hutchinson and Smith, 2006), with
Conclusion – the unusual combination of features in arid Australia
On one hand the present review has provided confidence in the outlines of the first framework of Stafford Smith and Morton (1990), while allowing for more effective re-stating of the initial propositions. On the other, it is notable that considerable areas of ecology covered by the framework have not advanced significantly by empirical analysis or quantification, such as analysis of soil moisture dynamics, soil–nutrient relationships, and ecology of invertebrate assemblages, to choose just a
Acknowledgments
The ARC–NZ Research Network for Vegetation Function, supported by the Australian Research Council and Landcare Research New Zealand, provided vital sponsorship to bring the authors together for the present paper. Staff members of CSIRO’s Alice Springs laboratory provided support for the initial workshop as well as a congenial home for SRM as a Visiting Scientist during preparation of the manuscript. Alan Andersen, Craig James and Brian Walker commented constructively on the manuscript, Dick
References (145)
- et al.
Fire maintains an Acacia aneura shrubland – Triodia grassland mosaic in central Australia
Journal of Arid Environments
(2008) Infiltration rates and soil moisture in a groved mulga community near Alice Springs, arid central Australia: evidence for complex internal rainwater redistribution in a runoff-runon landscape
Journal of Arid Environments
(2002)- et al.
Self-organized formation of banded vegetation patterns in semi-arid regions: a model
Ecological Complexity
(2006) - et al.
The ecology of Lerista labialis (Scincidae) in the Simpson Desert: reproduction and diet
Journal of Arid Environments
(2005) - et al.
Late Quaternary climates of the Australian arid zone: a review
Quaternary International
(2004) - et al.
Water flows on Cooper Creek in arid Australia determine ‘boom’ and ‘bust’ periods for waterbirds
Biological Conservation
(1999) - et al.
La Nina de Australia: contemporary and palaeo-hydrology of Lake Eyre. Palaeogeography, Palaeoclimatology
Palaeoecology
(1998) - et al.
Biogeography of the Acacia victoriae, pyrifolia and murrayana species groups in arid Australia
Journal of Arid Environments
(2006) - et al.
Spiders, spinifex, rainfall and fire: long-term changes in an arid spider assemblage
Journal of Arid Environments
(2006) - et al.
Leakiness: a new index for monitoring the health of arid and semiarid landscapes using remotely sensed vegetation cover and elevation data
Ecological Indicators
(2007)
Cenozoic climatic change and the development of the arid vegetation in Australia
Journal of Arid Environments
Understanding the surface hydrology of the Lake Eyre basin: Part 1-rainfall
Journal of Arid Environments
Understanding the surface hydrology of the Lake Eyre basin: Part 2-streamflow
Journal of Arid Environments
Bird assemblages of arid Australia: vegetation patterns have a greater effect than disturbance and resource pulses
Journal of Arid Environments
Long-term changes in lizard assemblages in the Great Victoria Desert
The fall and rise of Dr Pangloss: adaptationism and the Spandrels paper 20 years later
Trends in Ecology and Evolution
Fire regimes in the spinifex landscapes of Australia
Ant biodiversity in arid Australia: productivity, species richness and community organisation
Records of the South Australian Museum Monograph Series
Ant diversity in arid Australia: a systematic overview
The Ecological Web: More on the Distribution and Abundance of Animals
Insects ‘down under’ – diversity, endemism and evolution of the Australian insect fauna: examples from select orders
Australian Journal of Entomology
Fish larvae, growth and biomass relationships in an Australian arid zone river: links between floodplains and waterholes
Freshwater Biology
The Australian flora: its origin and evolution
Rangelands 2008 – Taking the Pulse. National Land and Water Resources Audit, Canberra
The ‘‘fire stick farming’’ hypothesis: Australian Aboriginal foraging strategies, biodiversity, and anthropogenic fire mosaics
Proceedings of the National Academy of Sciences
The impact of Aboriginal burning on the Australian biota
New Phytologist
Fire regimes and biodiversity in semi-arid mallee ecosystems
Comparative ecology of two populations of Pseudomys australis in northern South Australia
Wildlife Research
Gibson Desert birds: responses to drought and plenty
Emu
Evidence of altered fire regimes in the Western Desert region of Australia
Conservation Science Western Australia
Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota
Molecular Ecology
Flooding, soil seed bank dynamics and vegetation resilience of a hydrologically variable desert floodplain
Freshwater Biology
Mulga bird communities. I. Species composition and predictability across Australia
Australian Journal of Ecology
The biology and Aboriginal use of the honeypot ant, Camponotus inflatus Lubbock, in Northern Territory, Australia
Australian Entomological Magazine
Endemism in the Australian flora
Journal of Biogeography
Patterns of invertebrate biodiversity across a natural edge
Austral Ecology
Trophic trickles rather than cascades: conditional top-down and bottom-up dynamics in an Australian chenopod shrubland
Austral Ecology
Population dynamics of three species of dasyurid marsupials in arid central Australia: a 10-year study
Wildlife Research
Population dynamics of two species of dragon lizards in arid Australia: the effects of rainfall
Oecologia
Long-term dynamics of rodent populations in arid Australia: the influence of rainfall
Wildlife Research
‘What they call that in the whites?’: Ngiyampaa and other place names in a New South Wales Ngurrampaa
Respiratory strategies of tenebrionid beetles in arid Australia: does physiology beget nocturnality?
Physiological Entomology
Systematic variation of soil infiltration rates within and between the components of the vegetation mosaic in an Australian desert landscape
Hydrological Processes
Introduced mammals in Australian rangelands: future threats and the role of monitoring programmes in management strategies
Austral Ecology
Pre-European fire regimes in Australian ecosystems
Geography Compass
Population dynamics of the Australian plague locust, Chortoicetes terminifera (Walker), in central western New South Wales. I. Reproduction and migration in relation to weather
Australian Journal of Zoology
Evaluating the dingo as a trophic regulator in Australian ecosystems
Austral Ecology
The fire history of an arid grassland: the influence of antecedent rainfall and ENSO
International Journal of Wildland Fire
Cited by (0)
- 1
Present address: CSIRO Ecosystem Sciences, Private Mail Bag, PO, Aitkenvale, Queensland 4814, Australia.