I would like to acknowledge the Wurundjeri people of the Kulin Nations, the owners of the land on which The University of Melbourne stands. Furthermore, I would like to add that in my view, all of Australia is customary Aboriginal land. I would also like to acknowledge the conference organisers; this is a very timely and much needed conference.

I have been asked to speak to you this morning on the state of Australia’s biodiversity. As I am a terrestrial ecologist, my comments today will be largely restricted to the terrestrial domain. So, let me upfront acknowledge the extraordinary marine biodiversity that is within Australia’s legal responsibilities, and note that it faces different but equally demanding pressures over the coming decades.

I sincerely wish I had some good news for you today, but unfortunately I do not. By any measure, we are now in the midst of the 6th mass extinction of biodiversity in the history of Earth(3), and the first to be driven by human activity. The main proximate causes of biodiversity loss are habitat destruction and degradation (including fragmentation), invasive plant and animal species, and unsustainable levels of harvesting. Note that with the previous mass extinctions, it took around 5-15 million years for levels of biodiversity to recover. However, unlike prior extinction events (which have come and gone), this time the root cause - the appropriation of Earth’s biota and productive capacity for human use – is growing, with the aim of being a permanent feature. The loss of biodiversity threatens human livelihoods, health and wellbeing as documented by the Millennium Ecosystem Assessment (MEA)(4) and this loss is fundamentally and irrevocably changing human-nature relations. We must ask ourselves what will be left of nature 100 years from now. Half the world’s forests and most of its savannah woodlands have been cleared and degraded. Will these ecosystems persist beyond the 21st century? Will marine biota survive the industrialisation of the ocean’s natural resources? Unfortunately, the state of Australia’s biodiversity reflects a similarly parlous state.

The Convention on Biological Diversity defines biological diversity as the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems. Thus, biological diversity (or biodiversity for short), is usually examined at three levels: genetic, species, and ecosystems. So, today I will be making some comment on the conservation status of these three levels of Biodiversity in Australia.

Species conservation status

Australia has about 230 freshwater fish species, 214 frog species, 633 reptile species, 675 bird species and 378 mammal species (unfortunately, time prohibits me from making any comment about invertebrate species, fungi, or micro-organisms). Table 1 shows that the numbers (and percentages) of species in each animal group listed as threatened under the EPBC Act are: 27 freshwater fish (12%); 26 frogs (12%); 45 reptiles (7%); 70 birds (10%); and 99 mammals (26%). These are unhappy numbers, especially for mammals. 

We recently reviewed the conservation status of all Australian vertebrate animal species and identified species listed in one of the IUCN threat classes under (i) state legislation and (ii) by non-legislative authoritative assessments such as national action plans. This more expansive list (Table 1) shows that the number and percentage of species in each class assessed as being of concern at least at a regional level are: 90 freshwater fish (39%); 92 frogs; (43%), 253 reptiles (40%); 209 birds (31%); and 212 mammals (56%). The difference can be readily explained as a species tends to be only listed under the EPBC Act when it falls within the highest IUCN category and is threatened across its entire natural range. The way the EPBC Act is being implemented, a species has to be in very serious trouble across its entire natural range before it is federally listed. It follows that regional declines are not considered of national significance.

I argue the opposite – regional declines represent the extirpation of local populations and this is of immense evolutionary significance. After all, it is the population – not the species – that is the unit of evolution. Ernst Mayr (the father of the so-called modern genetic-evolutionary theoretical synthesis) defined evolution as the change in the characteristics of a population over time.(5) The extirpation of a local population can represent the loss of intra-species genetic diversity, though analytical techniques based on molecular data are needed to verify each case. Equally importantly however, the loss of any population represents a loss of evolutionary potential, as populations are the basic building block of future genetic variation and speciation.

Secret extinctions

The loss of biodiversity at the genetic-population level can be thought of as ‘secret extinctions’; as this loss is generally not recognized and usually falls below the conservation assessment radar. Thus, the extinction of a species represents the end point of a long journey of local extirpations and regional declines.

Another secret extinction involves the loss of ecosystems. Unlike much of the Northern Hemisphere, Australia was only marginally affected by the glacial events of the last 1,000,000 years.(6) This means Australia has ancient landscapes where species have been evolving in situ for tens of millions of years and have formed interactions with other species, the soil and landform that reach far back in time. Globally unique and ancient regional ecosystem complexes that have been largely destroyed include the South West Australian Floristic Region and the Brigalow Belt in Southern Queensland. Generally, the loss of ecosystems continues unabated, largely because we have only a poor understanding of the geography of ecosystems. Note that the EPBC Act refers only to ecological communities, not to ecosystems per se.

Regional conservation challenges

Keeping our focus at this landscape ecosystem level, I will examine some of the regional and sectoral conservation challenges Australia faces in the coming decades.

Woodland ecosystems
The conservation status of woodland dependent species and associated ecosystems warrants special attention. As I have already mentioned, subtropical and temperate woodlands have been largely decimated as they correlate with optimal climatic and soil conditions for intensive agriculture, especially cropping and improved pastures. Thus, these landscapes have been subject to extreme habitat loss, fragmentation and degradation. Here, the only viable conservation strategy is to ‘protect what’s left’ and implement large scale ecological restoration projects, such as the Gondwana Link programme.(7) I will comment on the intact woodland country later.

The rangelands
About 56% of Australia is covered by a contiguous cover of native vegetation and is under commercial grazing lease, the so-called rangelands.(8) These landscape ecosystems suffered a mass extinction of ground-dwelling mammals in the decades following European occupation and settlement, due to competition and predation from introduced herbivores and carnivores around water holes and restricted high productivity oases.(9) Now, the ecological integrity of the rangelands is threatened by the intensification of grazing and the modernisaton of the pastoral industry. The threat to biodiversity in the rangelands is therefore associated with habitat degradation rather than habitat loss and fragmentation per se. 

Habitat degradation in the rangelands can be assessed as a function of changes in the condition of the vegetation cover (such as a loss of productivity, reduction in species richness, and simplification of the structure). Changes in rangeland vegetation condition can be estimated by models based upon the piosphere effect, with vegetation conditions varying in relation to the distance from surface water, stocking densities, and the palatability of the vegetation.(10) The conservation challenge in the rangelands over the coming years includes devising and implementing ecologically-based natural resource management for biodiversity conservation in country which is currently managed to optimise its economic production values. From this perspective, the leasehold system provides a potentially invaluable legal instrument for incorporating biodiversity conservation values into rangeland natural resource management.

Intact country 
The two remaining climatically humid regions of Australia with the largest extent of intact country are (a) Northern Australia, from Kimberley to the Cape; and (b) the Great Western Woodlands of WA. The conservation challenge here is one of protection from intensive, destructive land use activities and managing extensive threatening processes. Unlike southern Australia, northern Australia has not been subjected to extensive land clearing and water impoundment. However, its biodiversity is threatened by more subtle processes including changed fire regimes, invasive plants, and introduced herbivores and predators. The Great Western Woodlands is around 16 million hectares of temperate woodland and heathland south of Kalgoorlie, wedged between the rabbit proof fence and the Nullarbor Plain. It is largely unallocated crown land but is subject to extensive exploration and intensive mining operations for gold and zinc. The future of the entire region is uncertain and the biodiversity significance of the region is such that it warrants the same kind of ‘whole of landscape’ legal framework developed for conserving regions such as the Wet Tropics of Queensland and the Great Barrier Reef.

Around 40% of Northern Australia is Aboriginal land and most of the Great Western Woodlands is subject to Native Title claims. This statistic serves to remind us of the crucial role Indigenous Peoples have to play in the long-term conservation of Australia’s biodiversity. The future of much of Australia’s biodiversity will depend upon conservation management by Indigenous Peoples on Indigenous Lands.

Forests
One of the fundamental limitations of the EPBC Act is that it does not afford protection to forested lands subject to Regional Forest Agreements. Forests are the most biologically productive ecosystems and support the highest densities of species and populations. There are actually two separate processes that lead to landscapes being species rich. One process relates to the evolution of species via long periods of isolation and relative environmental stability in ancient landscapes (such as the South Western Australian Floristic Region). The other process is called species-energy theory and is a major reason why forests have such high levels of species richness and animal abundance. This theory predicts that species richness and abundance increases with the productivity of ecosystems, that is, where environmental conditions are most conducive to photosynthesis and biomass production. The idea is that there is more energy (and hence habitat resources such as food) in the ecosystem which can in turn support a larger and denser food chain.(11) Unfortunately, in my professional opinion the Regional Forest Agreements did not deliver the conservation commitments agreed to in the National Forest Policy Statement.(12,13) Consequently, the long term conservation of Australia’s forest dependant populations, species and ecosystems remains uncertain. 

In recent years we have developed a greatly enhanced scientific understanding of the role of forest ecosystems in the water and carbon cycles. Specifically, the unique ecosystem services provided by mature forest ecosystems have now been quantified with respect to wildlife habitat(14), carbon storage(15), and water supply(16). The ongoing provision of these ecosystem services is a major practical reason for biodiversity conservation in forests, due to the relationships between biodiversity and ecosystem function.(17) The term ‘ecosystem services’ does not appear in the EPBC Act, and in this respect the Act is deficient. The failure to recognize the link between biodiversity and ecosystem services is a major concern given that these services are, among other things, part of Earth’s life support systems, including the global climate system.(18) 

Concluding comments

It is probably still not commonly appreciated that the human species, Homo sapiens, only evolved around 180,000 years ago, with humans arriving in Australia around 50,000 years ago. The conservation significance of this simple fact has still not been absorbed into our scientific understanding of the Australian landscape. While 50,000 years is too recent to have significantly affected the evolution of Australia’s species, it is very significant in terms of ecological time. For 170,000 years prior to the advent of agriculture, domestication of stock, and large settlements around 10 000 years ago, Homo sapiens developed cultures (values, social customs, economies, institutional arrangements, technologies etc.) that reflected close interactions and dependencies on the natural environment. These traditional human cultures persisted through periods of major and often rapid global climate change. For example, when humans evolved, the Earth system was in the dip of a major glacial trough that bottomed around 140 000 years ago, with an average temperature between 4-10o C cooler than present(19). Traditional-human nature relations(20), such as the Traditional Obligations to Country of Australian Aboriginals(21) are the well-spring of contemporary human–nature relations, and have an ecological basis that is not purely symbolic. They may have much to teach us about living with nature in a rapidly changing world. 

To conclude, the conservation of biodiversity and natural and associated cultural heritage demands a landscape-wide approach that recognizes the importance of ecological and evolutionary processes operating at geographic and time-scales far beyond those that guide conventional public policy and planning; an example of such an approach is The Wilderness Society’s WildCountry programme. We need legal frameworks at all levels of governance that support this kind of big picture thinking.

Table 1. A comparison of the difference in the conservation status of Australian terrestrial vertebrate animal species between (a) the EPBC Act and (b) state and territory legislation plus authoratative national assessments. Statistics are correct as of September 2004. Further details available from the author.