Is Australian wildlife fair game?Is the growing commercial use of Australian wildlife compatible with good conservation?
Key text
Key textWhile many people find putting a dollar value on our wildlife unpalatable, others have developed a taste for it. For example, the kangaroo industry – skins and meat for human consumption – is estimated to be worth around $200 million a year. The plant-based bushfoods industry, which markets products such as the Kakadu plum, roasted wattle seed and quandongs, was worth $14 million in 1996 and is growing rapidly.And there’s more to it than food. Many Australian animals are popular as pets – reptile enthusiasts have been known to fork out more than $5000 for a single live green tree python, while overseas bird-keepers hardly squawk while paying $9000 for a red-tailed black cockatoo. The wildflower industry is also blooming, earning an estimated $50 million for growers in 2005. The recent expansion in the commercial use of Australian wildlife has sparked a keen debate: will it lead to better conservation, or will it threaten the survival of species?
Harvesting, ranching and farming
Australian wildlife can be used in several different ways. Harvesting may be defined as the removal of wildlife living in a free-range wild population through the collection of plants or plant parts; the live capture of animals; the killing of animals; or the collection of eggs for immediate use. Well-known examples of harvesting are the felling of native trees, the kangaroo trade and mutton-birding on the islands of Bass Strait, but it also includes 'bush pick', which is the picking of seeds, flowers and fruits from wild-growing native plants. Ranching is the taking of animals from the wild to raise in a controlled environment for subsequent use as wildlife products or as live animal displays. In the Northern Territory, for example, crocodile eggs are taken from nests in the wild. They are then hatched in captivity and the juveniles are raised before being killed for their leather and meat or sold to reptile parks and zoos. Farming involves the breeding of wildlife or the cultivation of native plants in an enclosed environment such as a farm or nursery. So, although the original breeding stock was obtained from the wild, farmed plants or animals are not really ‘wildlife’ because they have been bred and raised in captivity. Farming is also distinguished from harvesting and ranching by an inevitable process of genetic ‘improvement’, whereby breeding stock is carefully selected to encourage desirable traits and to remove undesirable ones. This means that, over time, farmed plants and animals may become considerably different from their wild ancestors. Many Australian native plants are already being farmed, including tea tree, hoop pine, quandong, macadamia (in 2005 the macadamia industry was worth around $120 million a year) and a host of wildflower species both for the cut-flower industry and for garden plantings. Some animals, most notably the emu, are also farmed.
The debate
The commercial use of wildlife carries some conservation risks as well as some potential benefits. A vigorous debate has sprung up among conservationists, scientists, the animal welfare lobby, government departments and entrepreneurs.
Over-use
Those opposed to wildlife harvesting and ranching say that the use of wild species will lead to their decline and possible extinction. This has occurred in Australia: over-fishing has led to a decline in populations of orange roughy and abalone and in the 1920s the toolache wallaby was hunted to extinction. In fact, of the 500 animal extinctions estimated to have occurred worldwide in the last 400 years, hunting is blamed for around 23 per cent of them. But advocates say that with careful management it should be possible to harvest wild animals without precipitating population declines. Moreover these advocates say that by providing a monetary value to species – the 'use them or lose them' concept – people who might otherwise over-exploit particular species or destroy their habitat gain an incentive to conserve them and use them wisely. One of the main threats to wildlife in Australia is the clearing of habitat, much of which is carried out on private or leasehold land. Individual farmers, pastoralists and developers clear native vegetation for many reasons, but predominantly they do so in order to put the land to more ‘productive’ uses. Suppose they were able to make money from wildlife? Advocates suggest that many landholders may start conserving habitat if they were able to exploit their wildlife for commercial gain. Others disagree: it might make more economic sense, they say, to over-exploit such resources for a quick profit that could then be reinvested in some other venture. It could be a case of 'use them AND lose them'.
Non-target species
Another risk is the effect of harvesting and ranching on non-target species. For example, the extraction of a particular plant or animal may involve the use of vehicles in sensitive habitat, or might lead to the spread of weeds or fungal diseases. The reduction in numbers of one species might have ‘knock-on’ effects for other non-target species by, for example, making them more prone to predation.
Competition and gene pool contamination
Some conservation groups suggest that harvesting and ranching will inevitably lead to farming, in which formerly wild animals and plants are ‘domesticated’. Should these genetically ‘improved’ organisms escape into the wild, they might compete for habitat with the wild population or change its genetic make-up by interbreeding. Conversely, some scientists argue that farming with native Australian plants and animals would be more ecologically sustainable than present agricultural systems. This is because native species are adapted to Australia’s poor soils and highly variable rainfall and therefore make best use of available nutrients and moisture without damaging the environment. Whether native species would provide sufficient return to the landholder is unclear.
Farming might help resolve some conflicts over the use of wildlife. For example, many conservationists believe that the harvesting of native forests for timber degrades ecological and other values and threatens biodiversity, although the timber industry denies this. An increase in tree 'farming' – plantations of native and exotic tree species – might provide a solution. In Queensland, for example, conservationists, the timber industry and the Queensland government signed an agreement in 1999 to phase out native forest harvesting, coupled with an increase in plantations to meet the needs of industry.
Poaching and smuggling
The illegal taking of organisms from the wild – poaching – can have a deleterious effect on wildlife populations. In a way, the existence of poaching proves that certain wild species already have a monetary value. The smuggling of Australian birds, reptiles and, to a lesser extent, plants to national and international black markets is reputed to be big business. People opposed to the commercial use of wildlife say that legalising some operations will increase the impact of illegal activities because hardened poachers will focus their attention on very rare species not available legally. It may be difficult to distinguish between legal and illegal specimens, making it harder to police the trade effectively. And the legalisation of an Australian wildlife trade might increase demand, leading to an increase in poaching activities and the taking of an unsustainable number of organisms from the wild. But here, too, there are counter-arguments. For example, permitting the export and local sale of native plants and animals bred in captivity might eliminate the financial incentive to take from the wild. This would apply particularly to those species that could be bred in captivity more cheaply than they could be obtained from the wild.
The case of ‘superabundant’ species
Another argument in favour of the commercial use of wildlife concerns so-called ‘superabundant’ species. These are native animals – including some cockatoo and kangaroo species – that have benefited from the advent of agriculture in Australia and are now prospering to the extent that they are sometimes regarded as pests. Why not turn a problem into an asset? The commercial use of superabundant wildlife could simultaneously reduce the damage they cause to agriculture and provide a resource for a new industry. Such a scheme might also provide extra funds for monitoring and supervision to ensure that culling quotas are maintained at a sustainable level (Box 1: Kangaroo counting).
Issues of management
The arguments for and against wildlife harvesting often come back to whether harvesting can be maintained in the long term. After all, the modern history of humans versus wildlife mostly shows that wildlife declines as human influence increases. But many wildlife managers in Australia maintain that sustainable harvesting is technically possible – one of the key challenges, they say, is to harness the economic and social forces that might otherwise act destructively. Ensuring that resource owners see an economic benefit in a well-managed wildlife trade is one of the most important elements of this. Box 2: Principles relevant to the harvesting of native species sets out some principles developed by wildlife managers and scientists to help ensure the responsible use of Australian wildlife.
The future for native plants and animals
The commercial use of Australian native plants and animals will almost certainly continue to grow. Some products, such as bushfoods, are capturing the imagination of connoisseurs worldwide. Others are more controversial and will benefit from a continued, informed debate. All sides agree that Australian wildlife is precious: for its ecological role, for its place in Australian culture, and for its own sake. If we are to use it, the main thing is that we use it wisely.
It’s an argument that good scientific data might help resolve. How many kangaroos (of various species) are there? Are numbers going up or down? How many might we cull without endangering species? But there’s also a more basic question: how on earth do you count kangaroos? There are many different species; they occupy a wide range of habitats across much of the continent; and there are probably millions of them. The answer is you don’t do it on earth – you do it from the air. Since the 1970s scientists have been counting kangaroos from aeroplanes, using a technique known as fixed-wing aerial survey. They don’t count every single kangaroo – they take samples, which are used to estimate the total population. The exact details of the survey vary depending on the purpose of collection and the agency conducting it. The technique described here is just one variation and is based on that used for an Australia-wide survey.
Map marking
The first part takes place in the office. Using maps, the survey team divides Australia (or a given part of it, such as a State) into convenient blocks or strips: the Australia-wide survey used blocks of 1º latitude by 1º longitude in size. The area of this kind of block varies depending on latitude but is around 10,500 square kilometres. The team then marks out transects, or lines, in an east-west direction, wide enough apart so that the chance of kangaroos being ‘double-counted’ by moving from one transect to another is minimal.
Aerial survey
These transects form the basis of the sample survey, which is usually conducted in a high-wing single-engined Cessna. The plane maintains a height of 250 feet (about 76 metres), a speed of 100 knots (about 185 kilometres per hour) and a course that follows the transects marked on the map. Two people, one on each side of the aircraft, count the kangaroos they see in a 200-metre strip on the ground delineated by streamers attached to the wing-struts of the plane. Each counting period lasts for 97 seconds, during which the plane travels a distance of 5 kilometres. Thus, an area of 1 square kilometre (called a ‘unit’) is surveyed in each period by each observer.
Correction factors
It is very unlikely that even trained observers will count all the kangaroos in a unit – some might be hidden by vegetation and some might simply be missed because of the speed at which the plane is travelling. By comparing aerial counts with those obtained by ground-level surveys, scientists have demonstrated that a correction factor must be applied to the raw count to obtain an estimate of actual numbers. For red kangaroos, this is 2.29 in open vegetation, 2.36 in light cover, 2.43 in medium cover and 2.57 in dense cover. For western grey kangaroos, the correction factor is 4.8 in all habitats. Other correction factors apply to other species. Experiments at ground level have also shown a relationship between temperature and the ‘countability’ of kangaroos, since the animals are less active (and therefore less visible) at high temperatures. The temperature correction factor is expressed in the following equation:
C = 1/(1474 – 0.0316x) where C is the correction factor and x is the temperature (if it is above 15ºC).
An example
The following example is based on real data for the survey block 30-31º latitude and 144-145º longitude, an area of 10,663 square kilometres. Counts were made in two transects of 17 units (of 1 square kilometre) by two observers: these gave a total of 244 red kangaroos and 57 western greys in an area of 68 square kilometres (17 units × 2 observers × 2 transects). Note that there are statistical uncertainties associated with these counts. The 244 count has an uncertainty of about 6 per cent (because a count of another similar area might be expected to differ by up to this amount) and the 57 count similarly has an uncertainty of about 13 per cent. These uncertainties will affect the reliability of the final estimates of the number of kangaroos.
Correction factors
Applying the standard correction factors of 2.43 and 4.8 to the counts produces estimates of 593 and 274 for reds and western greys respectively. The average temperature during the count was 20ºC. Applying the temperature correction factor we get:
Number of red kangaroos = 593/(1.474-0.0316 × 20) = 704.
These are the numbers of animals estimated to have actually been present during the survey in all the units combined.
Density of animals
By dividing these numbers by the area surveyed (68 square kilometres) we calculate the corrected average number of kangaroos per unit, or average density (R). Thus:
R (red kangaroos) is 704/68 = 10.4 animals per square kilometre. Estimate of total numbers The total number of animals in the block is represented by the equation:
E = RZ Where E is the estimate of total numbers in the degree block, R is average density, and Z is the area of the block. Thus:
E (red kangaroos) = 10.4 × 10,663 = 111,000 animals. where these numbers have been rounded off to allow for uncertainties in the original counts. By adding the estimates for all the blocks together, we can produce an estimate for the total number of kangaroos in the region, State or continent. We can also use the data to generate an estimate of variance, which is a measure of reliability.
Review of survey technique
Scientists continue to review this survey technique. Helicopter surveys, while more expensive than fixed-wing surveys, may be more reliable. The correction factors, too, are widely debated, and research continues to refine them. This is important – the science of counting plays a fundamental role in our ability to manage kangaroos in a sustainable manner. We need to know we can count on the counters. Related site
To the same committee, Dr Brian Walker, the Chief of CSIRO Wildlife and Ecology, proposed a set of basic principles for ensuring sustainable use of wildlife. These were:
Related sites
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