8 Biodiversity | 1 Australia's biodiversity | 1.1 The importance of biodiversity
State of the Environment 2011 Committee. Australia state of the environment 2011.
Independent report to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities.
Canberra: DSEWPaC, 2011.
Australia’s biodiversity is important both globally and nationally. It is important to the world because of its uniqueness and its global significance, and it is important to Australians for both moral and utilitarian reasons.
The global importance of Australia’s biodiversity is due to both its richness and its uniqueness, as Steffen et al.1 describe:
Between 7 and 10% of all species on earth occur in Australia. More than 4500 species of marine fishes – and the greatest number of species of red and brown algae, crustaceans, sea squirts, and bryozoans in the world – live in Australian inshore waters. Fifty-seven per cent of all mangrove species are found in Australian intercoastal zones. There are more than twice as many species of reptiles in Australia as there are in the United States, and Australian deserts support more lizard species than any other comparable environment.
The uniqueness of Australia’s biodiversity is largely due to this continent being separated from other land masses for millions of years. In addition, the range and diversity of environmental conditions in Australia is different from most other countries due to characteristics such as nutrient-poor soils, high fire frequencies and a generally flat topography.1-2 Many of Australia’s species, and even whole groups of species that comprise taxonomic families, are endemic (unique) to this continent (Table 8.1). As a result, Australia is identified as one of the world’s ‘megadiverse’ countries (Figure 8.1).
|Marine fish||One of the most diverse fish faunas in the world, with more than 4500 species|
|Sharks and rays||54% of the entire chondrichthyan fauna is endemic to Australia|
|Ectomycorrhizal fungi||95% endemic (22 genera and three endemic families)|
|Terrestrial vertebrates||1350 endemic terrestrial vertebrates, far more than the next highest country (Indonesia, with 850 species)|
|Terrestrial mammals||305 species, of which 258 (85%) are endemic; more than 50% of the world’s marsupial taxa occur only in Australia|
|Birds||17% of the world’s parrots occur in Australia—more than 50 species (second-highest level of endemism after Brazil and the same as Colombia)|
|Reptiles||89% endemic; some groups such as front-fanged snakes (family Elapidae), pythons and goannas are more diverse than elsewhere in the world; Australian deserts have the world’s highest diversity of lizard species|
|Frogs||94% endemic; around 230 total species of amphibians in Australia (highest level of endemism of any vertebrate group in Australia)|
|Marine invertebrates||17.8% of the world’s crustaceans, 22% of bryozoans and 29.4% of sea squirts occur in Australian waters|
|Vascular plants||91% of flowering plants are endemic; 17 580 species of flowering plants, 16 endemic plant families (the highest in the world) and 57% of the world’s mangrove species|
|Butterflies and moths||Many groups are unique to Australia|
Figure 8.1 Megadiverse countries
Australia’s biodiversity is globally significant in both the terrestrial and marine environments. Chapter 6: Marine environment points out areas of Australia’s marine environment that are particularly biodiverse. South-western Australia has been identified as one of 34 global ‘biodiversity hot spots’. These are estimated to include 50% of the world’s endemic plant species and 42% of all endemic terrestrial vertebrate species.4
This use of ‘hot spots’ is a global definition that refers to places in which not only levels of biodiversity, but also previous loss of habitat and ongoing pressures, are exceptionally high.4 Overall, these hot spots once covered 15.7% of the world’s surface, but 86% of that area has been destroyed. The latest analyses are an update of the published analysis by Myers et al.5
The distribution and abundance of biodiversity are uneven across Australia. Australian biodiversity hot spots, defined by the Australian Government as areas in which the numbers and diversity of species are higher than elsewhere, are distributed in the north, south, east, west and centre of the continent (see Section 2.3). Efforts to conserve remaining biodiversity are likely to be most effective in these areas.
Australia is party to many international treaties and other agreements designed to protect biodiversity globally. National and state governments in Australia have also enacted policies and strategies to protect biodiversity within our borders.
There is increasing recognition that protecting other species is a smart strategy for the long-term benefit of humans.6 For example, the genes that are the basis for all life on Earth, and that determine what metabolic processes occur within a species and their products and byproducts, are a vital source of life-supporting resources for humans. Many of our crops, domestic animals, pharmaceuticals and other chemicals, building materials, fuels and many other products that have allowed humans to thrive in a range of environments, and respond successfully to many challenges, come from other species. The variety of genetic material in other species gave humans choices and options for dealing with challenges and opportunities. In addition, interactions of other species with the nonliving environment produce benefits for humans, such as water filtration; protection from floods; pest control; regulation of the atmosphere; formation of soil and maintenance of its fertility; and a range of physical, mental health and cultural benefits (Figure 8.2 and Table 8.2).
In contemporary Australian society, ways of thinking about the environment and the species that live in it are strongly influenced by the Western scientific tradition. This tradition has emphasised ‘reductionist’ science, which analyses and categorises the natural world in ways that simplify the complexity of interactions among species and the nonliving environment. The drivers-pressures-state-impact-response (DPSIR) model used in this report is an example of such a simplified, but informative and powerful, way of analysing the state of the environment. We also recognise that there are other philosophies of the environment that are more holistic and that do not separate humans from the natural environment (Box 8.1).
Many Indigenous people continue to have a close and multifaceted relationship with their land through particular plant and animal species and places of spiritual significance that may also be important habitats. In northern Australia and in coastal regions, in particular, Indigenous people also continue to harvest food, as well as fibre and other materials for art and craft production, from the land and seas. There are customs that govern harvesting, setting out the rights and responsibilities of harvesters, as well as governing relationships among and between people, and governing particular areas of land, and plant and animal species. The intersecting web of rights and responsibilities creates cross-accountabilities that monitor the behaviour of individuals so that plants and animal populations are not only used as a resource, but also managed with an eye to sustainability.
The effectiveness of these customary mechanisms for biodiversity conservation has been under serious challenge for many decades. As well as external pressures, such as land clearing, climate change and introduced species, there are changes within Indigenous societies, such as a shift to more sedentary lifestyles and store-bought foods, and increased assertion of individual preferences over customs for collective responsibility.
Against this background, the Indigenous land and sea management movement stands out for its growing professionalism and the capacity it has developed to address threats to biodiversity. Engagement in land and sea management is building the skills and knowledge of new generations of Indigenous people. Experiential learning draws from both the Indigenous ecological knowledge of their elders, and from science and applied conservation management, to observe and learn the effects that use and management have on key resources. Hallmarks of the growth of the movement are that 25% of the area of the Australian National Reserve System comprises Indigenous-owned land voluntarily dedicated for biodiversity conservation and associated cultural goals, and that more than 600 Indigenous rangers are employed to deliver environmental outcomes on these and other lands.
Australian Government facilitation and support has been important for the recent rapid growth and consolidation of Indigenous land management. Relationships between Indigenous people, researchers and staff of government agencies, regional-scale Indigenous organisations, catchment management boards, mining companies and nongovernment organisations have built recognition and respect for the strong role that Indigenous people can play as custodians and managers of biodiversity.
Jocelyn Davies CSIRO Ecosystem Sciences, Alice Springs—Biodiversity Portfolio, www.csiro.au/org/Biodiversity-Portfolio.html