Australia's threatened speciesEven though many species in Australia have become extinct since European settlement, there are also success stories such as the recent propagation of the Wollemi pine.
Key text
Key textWhen Captain Cook was exploring the east coast of Australia, he had with him a very talented young botanist, Joseph Banks. Banks quickly realised that he was observing thousands of plant species that were obviously unique. He and Cook went home excited by all the different plants and animals they had seen during the expedition. Soon the whole of Europe was talking and speculating about the strange flora and fauna of Terra Australis.Since then hundreds of species have become extinct in Australia, including at least 50 bird and mammal species and more than 50 plant species. It is likely that other species have disappeared too, without our knowledge (Box 1: The hidden species at risk). Biologists have now listed all those plants and animals that they know are at risk of extinction in Australia. These are called endangered species. The list includes 19 species of fish, 15 frogs, 14 reptiles, 46 birds, 36 mammals and 513 plants. In addition, there are many more species that are listed as vulnerable and some that are classified as rare. What threatens the continuation of species? There are two main threats to the continuation of species in Australia, and these threats have already caused extinctions. They are:
Land-clearing and the spread of towns and cities have destroyed many habitats. Fertilisers such as superphosphate have encouraged introduced pasture species at the expense of native grasses and the animals that feed on them. Conditions in many parts of Australia have always been harsh. Our flora and fauna have lived through droughts, fire and flood and they have done this largely by surviving in refuge pockets where conditions are less severe than in other places. But, with European settlement many refuges were destroyed and, in those that remained, feral animals also moved in and killed, or competed with, native species. Why does extinction matter? A certain level of biodiversity (biological diversity) is necessary to keep our ecosystems healthy. This is because each species performs a different function within an ecosystem. For example, some species allow pollination to occur, some recycle nutrients, some maintain soil fertility. Species interact with each other and rely on each other. One species may be a source of food for another, or may help keep another's population in check. As well as allowing natural ecosystems to function in a healthy manner, biodiversity is important for other reasons (Box 3: Australia's biodiversity). Extinction has always occurred; the important thing today is that the rate has greatly accelerated. This increased rate of extinction has already led to unstable ecosystems as well as to the loss of potentially useful species. For instance plants provide us with all of our food (directly or indirectly), as well as one-quarter of our medicines. The potential of many plants to supply food, medicines or other commodities remains unexplored. And what other useful compounds could exist in unknown plants? Can we prevent extinctions? If we are aware of the problem and are concerned for our unique plants and animals, there is a good chance that we will, at least, slow the rate at which organisms are becoming extinct. And there are some success stories to encourage us:
However, not all species under threat of extinction are being protected, nor is there sufficient funding to do so. Deciding how to allocate funds for threatened species programs is a difficult problem (Box 5: Survival of the cutest?). Who in government is responsible for protecting our threatened species? The Australian Government Department of the Environment and Water Resources is responsible for environmental policy issues. Within that department, the National Strategy for the Conservation of Australia's Biological Diversity is responsible for running programs aimed at protecting threatened species in Australia. Related Nova topics: Is Australian wildlife fair game? Impact of global warming on biodiversity
Many small organisms are important. For example, the living things in soil carry out all sorts of useful services such as decomposition, nutrient cycling and creation of good soil structure. Human activities – such as cultivation and the use of fertilisers, herbicides and pesticides – may all affect what lives in soil. For example, it is becoming clear that the increasing acidification that is a problem in several parts of the country is bad for the nitrogen-fixing bacteria that are so important to the growth of many crops and native plants. Many species still to be studied Below the soil, in regions of the Earth's crust once considered to be of interest only to geologists, life is also turning up. Bacteria have been discovered that thrive in near-boiling mineralised water or live immersed in hot oil hundreds of metres below the ground. Not much is known about the 'hidden' species in Australia. Biologists estimate that there must be at least 225,000 species of invertebrates here, but only half that number have even been described, let alone studied in detail. As life here has evolved in relative isolation for tens of millions of years, many of these invertebrates are not found anywhere else. Even less is known of our fungi and microbes.
Species from other countries are technically referred to as 'alien' or 'exotic'. The word 'introduced' is used to refer to species that occur outside their previous, natural range, and so can be used for alien species as well as for native species that have been moved to regions where they did not occur naturally – for example, koalas in Western Australia. Alien species often thrive in their adopted homelands because they have escaped the competitors, parasites and predators that kept them in check in their countries of origin. Feral animals are destructive 'Feral' is used to refer to animal species that are domesticated but which have been able to establish wild populations. Rabbits, foxes, cats and goats are particularly successful. The extent of the effects of feral cats on native animals is still under investigation. It is known that feral cats prey on various native bird and mammal species. Foxes are also serious predators and have been implicated in the decline, and possibly extinction, of some of our native species. Goats and rabbits have affected native vegetation cover and compete with native fauna for scarce resources. In some areas rabbits take over the burrows of native animals such as bilbies and bandicoots. Other major feral mammals are dogs, horses, water buffalo, pigs, donkeys, cattle, sheep and camels. Rats and house mice were probably brought in accidentally but have been very successful. Other problem species Exotic fish are common in most waterways. Trout, goldfish and European carp are particularly widespread. Exotic fish have been implicated in the decline, endangerment and extinction of several native fish species. Many invertebrates have also been introduced, but less is known of their effects because they are less obvious. However, some insect immigrants are very worrying. The European wasp, for example, probably came here as recently as the 1970s and is now spreading rapidly in south-eastern Australia. The wasps prey on native insects, including some which are important for pollinating native plants or crops. Exotic plants have also thrived, with non-native species accounting for about 15 per cent of our flora. Many of these alien species invade native vegetation and so are a serious cause of habitat change, which may in turn threaten native animals in the area. Related site
Australia has been declared one of the world's top 12 'megadiverse' countries. These countries carry so much of the planet’s biological richness that they have a special responsibility. Unfortunately, the other 11 countries do not have the degree of development, specialist knowledge and national wealth that we do. Australia is therefore the only megadiverse country in a position to study and conserve its diversity effectively. However, we have a fairly small human population in a large country with many species, so it will take a long time before we know what is here. Many aspects of our biodiversity are not well appreciated by the public. For example, Australia is incredibly rich in ants, reptiles, lichens and fungi. It has been observed that one small, wooded hill in Canberra contains more ant species than exist in the whole of Great Britain. Australia has many unique species Because of our continent's long isolation from other land masses, many species of our flora and fauna are not found anywhere else. (The island of New Guinea is the only other place that shares many of our indigenous species because it was joined to Australia until recently.) When a species is present only in one region or country and nowhere else it is said to be endemic to that place. Australia has a very high rate of endemism. Marsupials and monotremes (eg, kangaroos and platypus) are amongst the most well known endemic species. Although 70 species of marsupial occur in South America, Australia has the largest number in the world, with about 144 species. Monotremes are even more special, occurring only in Australia and Papua New Guinea. The most biologically diverse regions of Australia are the tropical rainforest – which accounts for only a tiny fraction of the continent’s area – and the Great Barrier Reef system. Both of these are almost entirely in Queensland, which therefore carries an immense responsibility in terms of global biodiversity. Related sites
But to do this we need to know, first, the range and extent of habitats that were present before colonisation, and, second, what habitats are present now and where they are located. We could go out and survey every square metre of land in the country, but that would take too long and cost far too much money – and it wouldn't tell us about those habitats that once occupied land which is now cleared. A different approach is to use mathematics. By using information collected in surveys, it is possible to develop mathematical relationships between different habitats and the environmental factors that determine where they occur – such as rainfall, temperature, soil type and position in the landscape. These relationships, or models, can then be used to predict habitat distribution in areas that have not been surveyed. It's a case of using the known to predict the unknown. CSIRO scientists in collaboration with the New South Wales National Parks and Wildlife Service, have done this kind of modelling in the forests of southeastern New South Wales. These forests have been subject to decades of dispute between conservationists, the timber industry and agriculturalists. As the political arguments have raged on, ecologists from different agencies have slowly been collecting data from large numbers of vegetation survey plots dotted throughout the forests. The scientists brought together the results of over 10,000 of these plots. They then used a statistical technique called regression analysis to relate the presence or absence of 96 eucalypt species to a wide range of environmental factors. In this way, they produced computer-generated mathematical expressions of the relationships between the eucalypt species and the environment. For the relationships to be useful in predicting the occurrence of habitats, one more tool was needed – a geographic information system, or GIS. This consisted of a computerised dataset containing information about the region, such as topography, soil and climate. The regression analysis showed the scientists the combination of factors that was needed in a location for a particular species of eucalypt to occur. They then used the GIS to find out where in the region such combinations of factors could be found. Using this technique, they produced a map predicting the pre-1750 distribution of tree species associations – or habitats – in the southeastern forests. The map has since been used by the NSW National Parks and Wildlife Service to add some 100,000 hectares to reserves in the region, including a number of habitat types that were previously under-represented. CSIRO scientists collaborated with the NSW National Parks and Wildlife Service, the Department of Land and Water Conservation, and local community groups to predict the pre-1750 distribution of vegetation in the central Lachlan catchment in western New South Wales. The map produced from the study could be used to aid remnant vegetation management and revegetation efforts in the region. Further reading
Bending lines with the mind (by Alastair Sarre),
Related sites
It is easy to love koalas, and even though they are not endangered their preservation and protection receive a lot of attention. This is good news for koalas, and it should certainly stay that way. The problem arises when we consider other species that are not as appealing as koalas but are under much more serious threats. Some species have no public appeal For example, how do you feel about saving rats? Many rodent species are native and have become endangered, but the public is not very concerned about this. Authorities have recently decided to rename these native rats using Aboriginal words, thereby making the animals sound more appealing and more Australian. It is hoped that people will become more motivated to conserve them. Many sharks are also becoming endangered, but we find it hard to accept that such gruesome predators should be protected rather than rounded up and killed. In the battle for dollars and political attention, the more appealing species tend to win. Often these are mammals (although not rats!) and, ironically, few of them play vital roles in our ecosystems. Emblematic species are national symbols Those species that sum up a country, region or way of life are called emblematic species. They are protected for reasons more economic and political than biological. For example, widespread outrage among voters and an unprecedented tourism disaster of economic significance would both eventuate if there were no koalas left in the wild in Australia. China would no doubt feel the same way about its pandas. Many African countries are making efforts to preserve their lions and elephants. But these are often only kept in special areas - the national parks – that no longer reflect the genuine original habitat with all its diversity. These problems also apply in Australia. Some of our emblematic species – the red kangaroo, for example – have benefited from agriculture to the extent that their numbers occasionally exceed pre-European levels. Culling or eating this particular national symbol is not popular, but it would be unlikely to affect the species because red kangaroos are far from endangered!
Teachers notes
Teachers notes Most mammal extinctions have occurred in the arid zone. The main causes have been the removal of vegetation cover by overgrazing, changed patterns of burning and competition with introduced exotic species such as cattle, sheep, rabbits, foxes, goats, donkeys and camels. Fragmentation of habitats – brought about by clearing areas in patches for agriculture, roads and settlements – has also contributed.
Teachers notes When making decisions we are, deliberately or instinctively, weighing up the advantages and disadvantages of our actions. Often, we need to rank these. Essentially, many decisions concerning the economy or the environment are made using a cost-benefit analysis. To make cost-benefit analysis an accurate tool, we need to quantify some of the supposed benefits and costs more accurately, especially those related to the quality of the environment. To quantify, it may be important to give dollar values to things that are not normally priced. Also the analysis may need to be extended into the future so that long-term benefits can be included.
Teachers notes
ANU Reporter May 2007, pages 10-11 Devil of a disease Reports on research into the Devil Facial Tumour Disease.
Australasian Science July 2007, pages 16-20 Toad kill (by Rick Shine) Examines the ecological impact of cane toads.
July 2007, page 9 Whale sharks in decline Reports on the declining numbers of whale sharks.
May 2007, page 8 Disinfectant hope for frogs Reports on a commercially available disinfectant which kills the chytrid fungus.
September 2005, pages 28-30 Ant threat to biodiversity (by Julien Le Breton) Describes the fire ant's invasion of Pacific islands, it's threat to biodiversity and attempts to control it.
July 2005, pages 14-16 The march of toads (by Ben Phillips) Suggests that cane toads are changing the ecology of Kakadu.
July 2004, pages 26-28 Exotic ants threaten indigenous lands (by Ben Hoffmann) Describes the threat of exotic ants to Kakadu National Park and efforts to control them.
Cosmos 15 November 2006 The dingo divide (by Benjamin Lester) Suggests that dingoes may be a valuable weapon against cats and foxes.
Ecos No. 135, 2007, page 4 Historic biodiversity case outcome (by Mary-Lou Considine) Reports on a court case that sets an historic precedent for threatened-species conservation.
Issue 134, 2007 pages 8-11 The long journey home for Campbell Island teal (by Ingrid Shepherd) Recent sightings of teal ducklings and nests on subantarctic Campbell Island are evidence of the success of a major rat-eradication and conservation program.
No 133, 2006, page 5 Call for more dingoes to restore native species (by Tracey Millen) Argues that reintroducing more dingoes to Australia would help control the population of nuisance pests and restore some native species populations.
No. 125, 2005, page 6 Threatened whale sharks draw calls to end exploitation Calls for more active protection measures for the migratory whale shark.
No. 121, 2004, page 32 A tracked green sawfish gives-up vital data Describes the first successful tagging and tracking of a green sawfish in Australia.
No. 119, 2004, Pages 28-30 Battlelines drawn against the cane toad march (by Sheila Lunter) Describes studies on the impact of cane toads on Australian native species and efforts to find a way to control the toad.
Nature 2 February 2006, page 530 Endangered species: Time to raise the devil (by Carina Dennis) Reports on research indicating that facial cancer is responsible for the decline in the Tasmanian Devil population.
New Scientist A collection of stories on endangered species is available.
11 November 2006, page 17 Kill the dingoes, and other species pay the price Suggests that the removal of dingoes allows introduced predators to cause the extinction of marsupials.
11 November 2006, page 10 Glimmer of hope for 'doomed' fish (by Debora Mackenzie) Suggests that it is still possible to prevent the decline of marine biodiversity.
4 November 2006, page 14 Lessons in the art of species survival (by Jeff Hecht) A new study finds that the extent of a species range and how its population changes over time is critical to its survival.
2 November 2006 Bring dingoes back to stop species extinction (by Rachel Nowak) Suggests that reintroducing Australia’s top natural predator could improve the survival of smaller marsupial species that they often prey on.
22 October 2005, pages 43-45 The sale of the lonesome pine (by Valerie Jamieson) Covers the growing and selling of Wollemi pines.
5 February 2005, page 10-11 Should we save Earth's biodiversity hotspots? (by Bob Holmes) Questions the value of saving the areas known as biodiversity hotspots.
20 November 2004, pages 6-7 Goodbye cruel world (by Bob Holmes and Duncan Graham-Rowe) The number of threatened species is dying out faster than ever, often due to increased human population and hunting pressures.
18 September 2004, page 12 Save rare parasites as well as primates (by Emma Young) Looks at how the extinction of a host species also brings about the extinction of other species dependent on that host.
9 September 2004 Threatened species total 'hugely underestimated' (by Emma Young) Suggests that the number of threatened species is underestimated because of species interdependence.
7 January 2004 Global warming threatens millions of species (by Shaoni Bhattacharya) Provides evidence that one in four land animals and plants will be extinct by 2050.
7 December 2002 Biodiversity (by Ann Fullick) Discusses the importance of maintaining biodiversity.
Scientific American March 2007, pages 14 Sympathy for the devil (by Wendee Holtcamp) Provides some ideas to save the Tasmanian devil.
September 2005, pages 44-51 Sustaining the variety of life (by Stuart Pimm and Clinton Jenkins) Looks at the unprecedented extinction rate and discusses incentives to preserve species diversity.
Provides an extensive range of information about Australia's endangered species. Click on 'Action plans and conservation overviews' for reviews of the status of different groups of organisms. Click on 'Information and resources' to find a series of fact sheets including 'Learn more about our threatened species'.
Threatened species (New South Wales National Parks and Wildlife Service, Australia)
Information on threatened species, native animals fact sheets, keeping Australian animals as pets, living with wildlife, habitat protection and treatment of sick injured or orphaned animals.
2004 IUCN red list of threatened species (International Union for Conservation of Nature and Natural Resources)
Searchable database of the world's plants and animals that are in danger of becoming extinct.
Plants and animals (Department of Conservation, New Zealand)
An overview of New Zealand's indigenous species. Click on 'Native animals' and 'Native plants' for fact sheets. Click on 'Native species management' for information about threats to native species and how species can be protected.
Australian Broadcasting Corporation (transcripts)
How gene pools work How Stuff Works, USA
Defines a gene pool and how it can shrink.
community. All organisms inhabiting a common environment and interacting with one another. ecosystem. A term used to encompass all the organisms in a community, together with the associated physical environmental factors (living and non-living) with which they interact. emblematic species. Species that are closely associated by the public with a particular region, nation or continent, or that seem to ‘sum up’ the region in question. For example, kangaroos for Australia, pandas for China, or kiwis for New Zealand. endangered. Used to refer to species (or higher levels of classification) that are likely to become extinct unless the various threats and pressures affecting them cease. endemic. Describes a species (or other unit of classification) that occurs in one particular region in all months of the year, and in all years. For example, the platypus is endemic to southeast Australia, and malaria is endemic to parts of Africa. extinct. Occurring no more. The word is usually used for species but can apply to any level of classification. Recent extinctions are hard to prove, and an ‘official’ limit of 50 years with no recorded sightings of the species is now used. genetic diversity. The variety of different types of genes in a species or population. Genetic diversity is really a form of biodiversity.
habitat. 1. The place normally occupied by a particular organism or population. invertebrates. Usually defined as animals without backbones, invertebrates make up the vast majority of all animal species. Only fish, amphibians, reptiles, birds and mammals are not invertebrates. Insects, spiders, worms, slaters and many marine creatures such as corals, sponges and jellyfish are examples of invertebrates. macropod. Literally meaning ‘big foot’, the word is used to describe kangaroos, wallabies and rat kangaroos. rare. Used to describe species with small populations or a very restricted distribution. Rarity may be a natural characteristic of some species, but it can also come about because of various pressures, and thus be a worrying sign about the future viability of a species. A rare species is more likely to become endangered or extinct, and so must should be treated carefully in management plans. regression. A mathematical relationship between two variables (eg, the height and weight of women in Australia). For simplicity, the relationship is often taken to be a linear one (ie, a straight line when plotted), but it can also be a curve. When the regression relationship for the variables is known, we can predict the approximate value of one variable from the value of the other. species. Living things of the same kind that are potentially capable of breeding and producing fertile offspring. Theoretically, plants or animals of different species cannot interbreed. However, occasionally this does not hold true. variable. Something that takes on different values that can be measured or counted. If one variable can be controlled exactly (such as the selling price of apples) then it is called an 'independent variable', while the remaining variable (in this case the number of apples bought) is called a 'dependent variable' vulnerable. Sometimes used synonymously with endangered, but also used to refer to species believed likely to move into the endangered category within the next 25 years if no action is taken.
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