1370.0 - Measuring Australia's Progress, 2002
Previous ISSUE Released at 11:30 AM (CANBERRA TIME) 19/06/2002
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Extinct, endangered and vulnerable birds and mammals(a)
Our plants, animals and ecosystems bring important economic benefits, are valuable to society and are globally important (Australia is recognised as one of 17 'mega-diverse' countries, with ecosystems of exceptional variety and uniqueness (SEE FOOTNOTE 3)). Most importantly, the ways in which organisms interact with each other and their environment are important to human survival: we rely on ecosystems that function properly for clean air and water and healthy soil.
Ideally, the headline indicator would consider all Australian biodiversity - the abundance and diversity of micro-organisms, plants and animals, the genes they contain and the ecosystems of which they form a part. But to measure change as comprehensively as this would be difficult, if not impossible (more than 60 core indicators for monitoring biodiversity were suggested for National State of the Environment reporting, for example (SEE FOOTNOTE 4)) and so here we focus on changes in the conservation status of one small component of biodiversity: mammals and birds.
This indicator ignores the vast majority of biological diversity. The numbers of threatened species are one aspect of biodiversity that can be measured. And we focus on mammals and birds because scientists know more about how these groups are faring than they know about many other groups. Moreover, a decline in birds and mammals threatens ecological processes and can point to a wider decline in biodiversity.
Changes to the list of threatened species should be treated cautiously. Species can be removed or added because of improved knowledge, not because they became more or less endangered. Indeed, sometimes new species are discovered, or those thought extinct are rediscovered. But over time, if the numbers of threatened birds and mammals increase substantially there is reason to believe that certain species are declining.
Between 1993 and 2001 the number of extinct, endangered or vulnerable bird and mammal species rose by over a third from 118 to 160 (of which 62 were birds and 98 were mammals). In June 2001 just under half of these species were vulnerable, a third were more seriously threatened (endangered) and the remaining fifth were presumed extinct. There were increases in the numbers of both endangered and vulnerable species, but the rise in species assessed as vulnerable was much higher (79%) than those assessed as endangered (18%). We do not know how much of this rise is because of new knowledge and how much is because of species decline, but many experts, such as those from the 2001 State of the Environment Committee believe that total Australian biodiversity declined during the 1990s. (SEE FOOTNOTE 2)
SOME DIFFERENCES WITHIN AUSTRALIA
As well as considering individual species, it is useful to consider entire ecosystems, which are the result of long-term interactions between the physical environment and living species. The area of land in conservation reserves is one possible indicator of the extent to which ecosystems are protected. This has been increasing and just under 8% of Australia's land was protected in areas such as national parks in 2000; (SEE FOOTNOTE 5) but there were gaps in coverage, including ecosystems in arid and semi-arid environments, native grassland, wetland and marine areas (some of this is discussed in more detail in the commentary Land clearance).
Among the States and the Territories, in the late 1990s the ACT had the largest proportion of land in conservation reserves (52%), followed by Tasmania (32%), South Australia (21%) and Victoria (15%). Only 2% of the NT and 4% of Queensland were in reserves, along with 6% of New South Wales and Western Australia. (SEE FOOTNOTE 5)
There are many examples of specific change, for the better or worse, in every State. For example, fox control in Western Australia helped the numbers of several threatened marsupials to increase over the 1990s, while in 2001 the NSW Government declared six woodland bird species to be vulnerable, primarily because of habitat clearing and fragmentation. (SEE FOOTNOTE 6)
FACTORS INFLUENCING CHANGE
Many factors threaten biodiversity. Species are often affected by more than one threat, and one threat can affect many species. Knowledge of ecosystems and their complex relationships is limited and a decline in one species can have important, perhaps unforeseen consequences elsewhere. Some conservation responses are shown in the box below.
The clearing of native vegetation is a particularly strong threat to terrestrial biodiversity. (SEE FOOTNOTE 2) This has had a profound effect on native wildlife, destroying plants and habitat for animals as well as helping invasive species to spread, which compete with native wildlife. Together with land clearing, the Commonwealth list of key threats to biodiversity includes a number of invasive species such as: foxes and cats (which prey on native species); rabbits and goats (which compete for and degrade land); and dieback fungus (which is damaging whole forests). Other important threats identified include: altered fire regimes, water use, salinity, climate change, pollutants, and fishing.
LINKS TO OTHER DIMENSIONS OF PROGRESS
Wildlife is important to many Australians - aesthetically, recreationally and culturally, particularly for many Indigenous Australians.
Biodiversity brings income and employment to Australia, through tourism for example (in 1995 half of international visitors went to a national park) (SEE FOOTNOTE 8) , while agriculture relies on a variety of services provided by biodiversity to keep soil healthy, water clean and crops pollinated. But economic activity - including land clearance for agriculture and flow-on effects like salinity - has been a major reason for the decline of many species. Invasive species have also played a role.
See also the commentaries Invasive species, Marine ecosystems, National income, Land clearance, Land degradation, and Inland waters.
1 The data were compiled from schedules to the Commonwealths acts, the Endangered Species Protection Act 1993 and the Environment Protection and Biodiversity Conservation Act 1999. Species are listed (and so counted here) at the subspecies level. Not all listed species are included: cetaceans (whales and dolphins) and seabirds are excluded because their survival depends on factors outside Australia and Australian waters, while species found only on islands far offshore (such as Norfolk Island) are excluded because the indicator's focus is continental Australia. The extinctions data have been backcast to allow for recent knowledge (i.e. if a species was presumed extinct in 1993, but then rediscovered in 1997, it is not included here as extinct in 1993).
2 State of the Environment Committee 2002, Australia - State of the Environment Report 2001, CSIRO Publishing, Melbourne.
3 The Wilderness Society 1999, Australia's Biodiversity - A Summary. URL: www.wilderness.org.au/members/tws/projects/General/biodivsum.html last viewed 13 February 2002.
4 Saunders, D., Margules, C. and Hill, B. 1998, Environmental Indicators for National State of the Environment Reporting - Biodiversity, Department of the Environment, Canberra.
5 Environment Australia 2001, Collective Australian Protected Area Database 2000, Environment Australia,Canberra. URL: www.ea.gov.au/ parks/nrs/protarea/pa99/intro.html last viewed 18 February 2002.
6 In October 2001 the NSW scientific committee determined the following six woodland species as vulnerable: Grey Crowned Babbler (eastern form), Hooded Robin (south-eastern form), Brown Treecreeper (eastern form), Black-chinned Honeyeater (eastern form), Speckled Warbler and Diamond Firetail. URL: http://www.npws.nsw.gov.au/news/tscdets/index.html last viewed 18 February 2002.
7 AUSLIG (Australian Land Survey Information Group) 1993, Land Tenure Map.URL: www.auslig.gov.au/facts/tenure/index.htm last viewed 14 February 2002.
8 Blamey, R. and Hatch, D. 1998, Profiles and Motivations of Nature-based Tourists Visiting Australia, Bureau of Tourism Research Occasional Paper No.2, BTR, Canberra.