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Biodiversity or biological diversity refers to the variety of lifeforms on this planet - its plants, animals, microbes and fungi, the genes that they contain and the ecosystems of which they are a part. Find out more.
All organisms rely on other lifeforms for their existence. Organisms using oxygen in respiration rely on plants for its production and food comes from plants, animals and fungi. Any change in numbers of one species will effect the lives of other species. Habitat degradation in the form of landclearing or introduction of foreign species is the main cause for losses in biodiversity. World agricultural trade depends on biodiversity. New varieties of livestock and crops are being bred continually from their wild 'cousins' in order to stay ahead of pests and diseases. These are being used to breed drought resistance, to boost nutritional content or to increase crop yields. Many common pharmaceuticals were first found in wild plants and animals and major searches are continuing around the world for new therapeutic compounds in wild species.
Australia is in a fairly unique position in the world as it contains a huge variety and number of species (an estimated 475,000 of the earth's 10 to 30 million species). Australia is one of only 12 'mega diverse' countries and the only one which is considered a 'developed' country. One striking example of this is a comparison of a hill in Canberra known as Black Mountain (the location of CSIRO's division of Entomology) with The United Kingdom. Black Mountain is home to more species of ants than exist in the whole of the UK.
It has been estimated that about 500,000 hectares of native vegetation are cleared each year in Australia. This human intervention in the physical landscape along with the introduction of species such as rabbits, foxes, cane toads and sparrows has been detrimental to Australia's biodiversity. There is much to be done in order to halt and reverse this trend. Conservation of the biological diversity within our ecosystems underpins Australia's economic and social health. These ecosystems depend on conservation management by landholders, communities and all levels of government so as to develop ways of using resources without compromising Australia's natural heritage. Australia has contributed to the International Convention on Biodiversity and has in place a national strategy for the Conservation of Australia's Biological Diversity.
What is CSIRO doing to conserve Australia's biodiversity?
Plant Biodiversity Research
CSIRO Plant Industry along with Australian National Botanic Gardens has established the Centre for Plant Biodiversity Research. The centre is home to more than a million plant specimens, and a whole new concept in biodiversity monitoring. Documenting Australia's botanical diversity, 80% of which is found nowhere else in the world, is the main function of the herbarium. This involves establishing the identity and relationships of native plants, as well as their geographical distribution and ecology. In an effort to conserve Australia's rare and threatened plants, CSIRO Plant Industry scientists are working towards identifying the genetic differences between rare and common species. The scientists are also working to assess genetic and ecological impacts of habitat fragmentation.
Comparing the levels of genetic variation within rare species to those of closely related common species can identify any consistent differences in the amount and distribution of genetic diversity. This information will provide the guidelines for rare plant management and conservation.
Scientists are also studying plants that were once widespread and common, but which are now rare due to clearing woodlands and grasslands for agriculture. One such study was of remaining populations of a threatened grassland daisy Rutidosis leptorrhynchoides. Results of studies of this plant, better known as the Button Wrinklewort, have shown that as population size decreases genetic diversity is lost and inbreeding increases due to increased self-pollination.
In the long-term, a loss of genetic variation (sometimes referred to as "genetic erosion") will leave species with few evolutionary options in the face of changing environmental pressures. In the short-term, increased inbreeding can dramatically affect the chance of the plants' survival. Inbreeding results in offspring that are not as fit as their parents, producing plants that do not grow as quickly, set as many flowers, or have as many seeds.
Remnants of what was once one of the most extensive native ecosystems in south-eastern Australia have been found in some odd places. Rather than being found in national parks, stands of white box woodlands exist in several cemeteries, a road strip about 300 metres long and within a travelling stock reserve. It has been estimated that only about 0.01% of the original grassy white box woodlands exists in a relatively pristine state. By studying the biodiversity of the woodlands and the genetics of white box trees, CSIRO scientists have devised a conservation strategy for this particular ecosystem. The scientists propose the formation of a new type of reserve consisting of small, high quality sites scattered across NSW and larger lower quality fragments. These would be linked administratively by the agreement of the various authorities, including private individuals responsible for the land.
CSIRO scientists are continuing their assessment of the genetics of naturally rare plant species in order to protect Australia's biodiversity. Research will also be focussed on building genetic and ecological models of small, remaining, native plant populations. This will provide scientists with tools to predict future survival and conservation value of Australia's native plants.
Bettong and Western barred bandicootWith the support of Earthwatch Australia, CSIRO is working to reintroduce the burrowing bettong Bettongia lesueur, a native marsupial about the size of a rabbit, to the mainland. Removal of habitat and predation by feral foxes and cats brought the mainland population to extinction in 1942. Strong populations remained only on Bernier and Dorre islands. By creating a fox and cat free zone at Heirisson Prong in WA, CSIRO scientists are showing that it may be possible to get native animals back to where they once flourished. Similar work is being done by CSIRO scientists at Shark Bay, WA with the western barred bandicoot.
Birdwing butterfly (excerpt from Ecos 84)
The endangered Richmond Birdwing butterfly has come under increasing pressure from the razing of remnant rainforest verges in southern Queensland and Northern NSW. In addition, a Brazillian vine sold in nurseries has distracted the butterfly away from the native vine Aristolochia praevenosa on which it normally lays its eggs. The introduced vine Aristolochia elegans, known as 'Dutchman's pipe', is toxic and poisons the emerging caterpillars which feed on it.
Dr. Don Sands of the CSIRO Division of Entomology recognised the dwindling of the butterfly's habitat and so set out to remedy the situation. He used simple seed selection techniques to breed a drought resistant variety of the native rainforest vine. With the help of a nursery run by an aboriginal co-op, CSIRO's Double Helix Science Club and children from over 100 schools across the butterfly's former range, a planting program was put into place. At the same time, a community effort began to remove the imported Dutchman's pipe.
The program has successfully reintroduced the butterfly into its former range and has led to an important spin-off. Recognising that the Birdwing caterpillars prefer relatively soft vine leaves, Sands has developed a device called a 'leaf penetrometer'. It is hoped that this device will aid in selecting crop species for leaf toughness and therefore insect pest resistance.
Using fire as a land management tool
Fire is thought to be a natural part of the environment of south-western Australia. CSIRO Wildlife and Ecology scientists have been investigating how well the flora and fauna could survive and recover from management fires. Fire provides one of the few relatively inexpensive management tools which could be used to promote regeneration of native plant species.
The studies showed that weed cover was not encouraged by burning (this was an initial concern about the process) but that in areas of ground disturbance such as fire breaks and road verges. The studies suggested that regeneration of trees such as Salmon gum, Wandoo and York gum can be promoted by fire (and other types of disturbance) but that the weed problem has to be dealt with too.
Regarding the effect on fauna, the results showed that if fire is to be used as a management tool in small isolated reserves it is important to ensure that some habitat of all species is not burnt. This practice ensures that there are refuges for the species, which at a later date can recolonise the burnt area.
Artificial water holes and biodiversity (excerpt from Ecos 92)
A team of ecologists from CSIRO's division of Wildlife and Ecology have set out to clarify the impact of domestic and other grazing animals on rangelands biodiversity. The study found that bores and troughs are a potential threat to biological diversity of native plants and animals in arid and semi-arid regions. Artificial water points now exist at high densities over much of the rangelands. This has allowed animals to remain on country where once they couldn't have survived and has created sustained grazing pressure across large areas leading to degradation of the land. Most of arid Australia was naturally waterless and its native plants and animals are adapted to such conditions.
Recommendations coming out of the study include strategic closure of artificial water points in conservation reserves and the testing of selective water-closure to balance production and conservation goals outside conservation areas. There is a need for future research to adopt a regional perspective, collaborating with land managers in order to strike a balance between the needs of the pastoral industry and the needs of the native plants and animals that are not coping well.