Conservation benefit from harvesting kangaroos:status ...10246/gg_new_mil_kang.pdfConservation benefit from harvesting kangaroos:status report at the start of a new millennium A Paper

Conservation benefit from harvestingkangaroos: status report at the start ofa new millenniumA Paper to stimulate discussion and researchGordon GriggDepartment of Zoology & Entomology,The University of Queensland,Australia 4072www.zen.uq.edu.au/people/[email protected]

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Pages 53 - 76 in A Zoological Revolution. Using native fauna to assist in its own survival. Edited by Daniel Lunney and Chris Dickman, 2002. Royal Zoological Society of New South Wales, Mosman 2088 and Australian Museum.

Over the last twenty years, kangaroo harvesting has gained much greater publicacceptance and risen in monetary value.However,most landholders still regardkangaroos mainly as pests, and are a long way from making enough money fromkangaroos to encourage any shift away from their focus on sheep.Yet kangaroomeat is now sold legally for human consumption in all Australian States and iscommon on restaurant menus, while its export is rising steadily. Extensiveaerial surveys have established the abundance of the three large kangaroospecies and their resilience to harvesting. A small number of landholders arebenefiting from kangaroos, either by selling access to shooters/processors orthrough direct involvement as licensed operators.The International Union forthe Conservation of Nature has supported the concept of achievingconservation benefits from the sustainable use of wildlife, and this has beenincorporated into kangaroo management programs (for leather and meat) bymost Australian governments. Despite all these positives, the low price ofkangaroo meat, which has still not found the place it deserves on theinternational game meat market, is a major impediment to implementing“sheep replacement therapy for rangelands”, and only when prices risesignificantly will landholders choose to reduce sheep numbers and invest theirhopes in kangaroos. Meanwhile, land degradation continues unabated and lowprices for coarse fibre wool, while encouraging woolgrowers in the sheeprangelands to overstock, also provide a stimulus to landholders to diversify.Alarmingly,many landholders are choosing to diversify into goats which, thoughprofitable in the short term, will extend the damage done by sheep.Low prices for wool from the sheep rangelands also amplify the clamour forkangaroo control, and governments are responding by researching orimplementing programs designed to significantly reduce kangaroo numbers.South Australia now has a program which, if implemented fully, would reducekangaroos by 60%. In Queensland and NSW, research projects are examiningmore effective ways to reduce kangaroo numbers. These goals reflect anacceptance of the folklore that competition from kangaroos compromiseswool production and markedly reduces sheep carrying capacity, even thoughscientific evidence for this is lacking.But reducing kangaroos will not bring the anticipated benefits towoolgrowers, because kangaroos at typical densities are a much smallercomponent of the total grazing pressure (TGP) than is generally assumed.This is because the factor of 0.7 DSE (dry sheep equivalent), by whichkangaroo numbers are translated into forage lost to sheep, is an over-estimate. Taking body weights into account the factor should be about 0.4

2 A Zoological Revolution

Sheep replacement therapy forthe rangelands: 20 years onAustralia has 50 species of macropod marsupials—the kangaroos, wallabies and rat kangaroos—of which many have suffered serious declines orbecome extinct since colonisation by Europeans,particularly as a result of habitat modificationassociated with grazing by introduced stock (seereview by Calaby and Grigg 1989). However, asmall number of species of large kangaroos—theRed Kangaroo Macropus rufus, Eastern GreyKangaroo M. giganteus and Western GreyKangaroo M. fuliginosus in particular—haveincreased markedly in abundance. They arepresent in vast numbers in many parts ofAustralia’s arid and semi-arid sheep rangelands, amostly degraded area occupying about 40% ofthe continent, where they coexist with about15% of the nation’s sheep flock (Figure 1). Theinitial degradation was caused by the woolindustry, with sheep numbers driven by the 19th

century English wool market without regard forthe impact of overgrazing on the land (Lunney2001), which was exacerbated by the rabbitplague. Total grazing pressure remains an issue

today. This paper reviews the case for anecologically sustainable kangaroo industry to helprestore the degraded rangelands.

For nearly 20 years I have been promoting themajor conservation benefits to Australia’s sheeprangelands that could be gained from expandingthe export market for kangaroo products. Thiscould enable landholders to derive significantincome from kangaroos, while reducing sheepnumbers in the marginal lands and avoidingfurther land degradation. I have referred to thisidea as “sheep replacement therapy for range-lands”. Its first formal, published exposition waspublished by the Royal Zoological Society ofNSW (Grigg 1987), with a subsequent all-dayRZS Symposium in Sydney in May 1988 whenthe idea was scrutinised by a range of biologistsand other interested parties (Lunney and Grigg1988, Grigg 1988). Since then I have advocatedthe idea at scores of meetings of pastoralists,conservationists and scientists from Perth andAdelaide to Longreach, and Brisbane to Dubbo,Blinman and Wagga Wagga, as well as publishingmore than 20 papers and articles on the subject(Appendix 1).

and, taking measurements of field metabolic rate into account, may be as lowas 0.15-0.2. Hence, even if the desired reductions in kangaroos could beachieved, there would be little or no difference to the economic viability ofwoolgrowers in the sheep rangelands. Furthermore, if governments decide toinstitute significant reductions in kangaroos without data to confirm theconservation and economic benefits of doing so, there will probably bestrong criticism from conservation and animal rights organisations as well asfrom Australians at large, and this approach may have to be abandoned.For these reasons, the focus of kangaroo management as pest control aimed atimproving wool productivity is doomed to failure. I still support the alternativeview that the best way to reduce grazing pressure on the rangelands is byreducing sheep, and that the best way to achieve this is to develop a market fora high-value kangaroo industry and to sell its monopoly product on the worldmarket for game meat. A significant increase in the value of kangaroo meatcould make the harvest of free-range kangaroos for skins and meat a profitableand ecologically desirable enterprise for landholders. This would harnesseconomic incentives in the service of ecological sustainability and rangelandrehabilitation and thus provide another example of achieving conservationgoals through the sustainable use of wildlife. Furthermore, the development ofa high value, sustainable kangaroo industry stands in sharp contrast to thefatalism of some ecological commentators who can only prescribe massclosure of Australian rural communities and essentially evacuating marginalcountry. What is needed to achieve these desirable social, economic andconservation goals is a strong marketing effort and I provide some suggestionsabout the attributes of kangaroo meat and the benefits of kangaroo harvestingwhich could feature in a marketing campaign.

Conservation benefit from harvesting kangaroos

3A Zoological Revolution

The start of this new millennium is a good time toreview progress. The promised benefit has yet to berealised. Two to three million kangaroos are harv-ested every year. Their skins provide the mainstayof the industry, but meat is mostly sold at lowprices, for pet food, and kangaroos are still regardedby landholders as a pest rather than a resource.

Nevertheless, a lot has changed on the kangaroofront in the last 20 years. Kangaroo meat can nowbe sold legally for human consumption in allStates. There are guidelines to ensure hygienic

handling of the meat in the field and a Code ofPractice to ensure humane slaughter. Kangaroo ison the menu at many restaurants. Both local salesand the export of kangaroo meat for humanconsumption is rising. Its export has risendramatically from 2.8 million kg in 1995 to 5.8million in 2000 (Kangaroo Industry Associationof Australia [KIAA] April 2001 Newsletter, viewat http://www.kangaroo-industry.asn.au). This isonly 20% of the total weight of kangaroo meatsold, so there is a huge capacity to increase the

Figure 1. Density and distribution of a. Red Kangaroos, b. Eastern Grey Kangaroos, c. Western Grey Kangaroos,determined from aerial surveys over 1980-82 (modified from Caughley 1987b to take into account the mostrecent correction factors for aerial surveys of grey kangaroos) and (d) sheep. Ground surveys of much of theeastern part of the eastern grey kangaroo range over 1987-92 estimated a density of 10 kangaroos/km2(Southwell et al. 1997).

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sale of meat at a better financial return, withoutincreasing the number shot. Some landholdershave instituted kangaroo harvesting and othershave profited from charging for access tokangaroos on their properties. Importantly, therehas been a growing awareness of the potential togain conservation benefits from the sustainableuse of wildlife (see Grigg, Hale and Lunney 1995),as well as a formal endorsement of the concept bythe International Union for the Conservation ofNature in Resolutions 18.24 (Perth 1990) and2.16 (Amman 2000). Moreover, most Australiangovernments have adopted policies which supportthe sustainable use of wildlife (see, for examplewww.dlwc.nsw.gov.au/ care/land/wlr). So we havecome a long way.

But kangaroos are still far from providing asignificant source of income to landholders in thesheep rangelands. Is the idea flawed? Is it just thatchange comes slowly? Is the product not goodenough? Or is the product good enough but notyet recognised? I think it is the last of these, andthat the best hope of addressing land degradationin the sheep rangelands is to find ecologically aswell as economically acceptable alternatives tosheep. Kangaroos at high value would provide asignificant alternative. This paper reviews someof the main historic and current issues relevant tothis idea, and suggests a way forward.

Land degradation in the sheeprangelands: a huge issue in needof a solutionSheep grazing in the last 160 years has brought thesheep rangelands to their ecological knees. Thistrend must be halted and reversed if we are toavoid even more serious desertification. Thesolution will be to find activities that are bothfinancially profitable and ecologically benign to setthe stage for rehabilitation and restoration.Replacing sheep with goats, which is happeningparticularly in Queensland, is an unacceptablestrategy because it continues to take the land downthe path of degradation. Other uses for therangelands need to be sought. Many woolgrowersin these marginal lands are turning to cattle, butthis is unlikely to halt land degradation. Drylandagriculture (that is, growing crops in dry areas usingirrigation rather than rainfall) is increasing, but thisis far from ecologically benign. Ecotourism will be-come increasingly important, as discussed by Croft(2000), and it is entirely compatible with harv-esting, but it is also likely to benefit tour operators

in towns rather than the landholders. Removingthe imperative to run too many sheep is animportant priority because sheep in high densitiesdamage vegetation by overgrazing and degrade theland with their hard feet. Prices for coarse fibrewool are simply too low for most properties to beeconomically viable at stocking rates low enough tocontain, let alone reverse, the damage. Manyalternative land uses, such as cotton growing, resultin even greater deterioration of the land.

So, if the economics were better, kangarooharvesting could become an ecologically soundalternative to sheep in the fragile semi-aridrangelands. This would be compatible with therestoration of land and the recovery of otherwildlife. Kangaroos provide an existing largeharvest, proven by many years of experience to besustainable in the long term, with most of thelegislation, regulations, biological knowledge andindustry infrastructure already in place.Kangaroos in fact already provide a spectacularlysuccessful example of an ecologically sustainablewildlife harvest (Pople and Grigg 1998, Grigg andPople 2001). What is lacking is a good price forthe products at the “farm gate”, and a big enoughmarket for demand to exceed supply and, thus,stimulate higher prices.

Kangaroo issues then and now:howthe issues have changed in 20 yearsMy concern about all of this arose when firstflying aerial surveys of kangaroos with GraemeCaughley in 1975. This gave me a good look(from 250 feet/76 m) at the huge extent of landdegradation and the vast numbers of sheep andkangaroos in the rangelands. At that time the hotissues about kangaroos were:

• claims by some conservationists/preserv-ationists/humane societies that kangaroopopulations were threatened by harvesting(and, indeed, Senator Lionel Murphy asWhitlam’s Attorney General and Minister forCustoms and Excise closed the export ofkangaroo products in 1973 in response toconcerns raised at the time, leaving only localmarkets for the kangaroo industry);

• opposition to kangaroo harvesting from someanimal welfare lobbyists (e.g Rawlinson 1988,Arnold 1988);

• the perception by woolgrowers that kangarooswere a pest and compromised wool production(Gibson and Young 1988);



• a major Commonwealth enquiry (the House ofRepresentatives Select Committee on WildlifeConservation) which found in favour of “theprinciple that there is no reason why someanimals cannot be harvested provided theoperation is based on sound biologicalprinciples” (summarized in Lunney 1995), andwhich is what I call ecological common sense.

The claim that harvesting threatens kangarooswith extinction is now rarely heard, and neverheard from well-informed people. Opposition tothe industry on animal welfare/rights grounds isstill there and always will be. The third issue, thenotion of kangaroos as pests, is still firmly held inthe rural sector. It will be significantly challengedin this paper.

A fourth issue, the role of kangaroos in landdegradation, has emerged forcibly since the1970s. In fact there was little said about landdegradation in the 70s, although it was wellrecognised by 1901 as having occurred in theWestern Division of NSW (Lunney et al. 1994).In recent years it has become common forlandholders and some rangeland ecologists toregard kangaroos as a significant causative agentin land degradation, even though comparisonswith sheep are lacking.1. The growth of our understanding aboutkangaroo populations Extensive aerial surveys have put an end tospeculation that kangaroo populations werebeing harvested towards extinction. Partly as aresponse to Murphy’s ban, partly because wildlifemanagement in the 1970s was becoming morequantitative in approach, and partly becauseGraeme Caughley (then at the University ofSydney, later at the CSIRO) was developingimproved methodology, State and Federalagencies funded significant aerial surveyactivities. Led by Caughley, broad-scale surveyswere conducted in NSW (NSWAKS, first surveyin 1975), Queensland (QAKS, 1979) and SouthAustralia (SAKS, 1978, see Grigg et al. 1999 andPople and Grigg 1998). The Australian NationalParks and Wildlife Service (now EnvironmentAustralia) formed a Kangaroo PopulationMonitoring Unit under the direction of GerryMaynes and Colin Southwell which organized asurvey of Western Australia (a huge undertaking)and Queensland. In 1982 our team surveyedmost of the rest of the range of the Red andWestern Grey Kangaroos in what we called aRemote Areas Kangaroo Survey (RAKS) in the

Gibson and Great Victoria Deserts, using aCessna 206 with long-range fuel tanks. This filledin the gaps and enabled the first completepopulation assessments (Caughley et al. 1983). Asecond, slightly less comprehensive nationalsurvey was compiled again in 1984 (Grigg et al.1985) and another in 1987 (Fletcher et al. 1990).

Collectively, these Australia-wide surveys showedconclusively that kangaroo populations werehealthy, that is, not in decline at all, and were infact flourishing, and that the supposed threat fromharvesting was exaggerated or misguided (Grigg1984). At the time of the first Australia-wideestimate in 1982 there were at least 30 million Red,Eastern Grey and Western Grey Kangaroos, mostlyin the sheep rangelands, alongside about 30 million(15%) of Australia’s total of nearly 200 millionsheep (figures have been modified from theoriginally-published figures by the application ofmodern aerial survey correction factors).

Since then, comprehensive surveys in fixed-wingaircraft have been conducted annually in NewSouth Wales, South Australia and WesternAustralia (1/3 of State each year, by rotation)and, since 1991, there have been annualhelicopter surveys of representative monitorblocks in Queensland. The results of all of thesesurveys are used, together with other informationsuch as a knowledge of rainfall, to set annualharvest quotas. These surveys were conductedthrough good times and in severe droughts, withsignificant kangaroo harvesting throughout, andwe now have a huge amount of informationabout the population trends of kangaroos andtheir responses to rainfall (or drought) and toharvesting (see review by Pople and Grigg 1998,at http://www.environment.gov.au/bg/plants/wildlife/roo/roobg.htm) and Figures 2 and 3.

The upshot is that we can be sure that rainfalland forage availability drive the short-termchanges in population numbers and we knowfrom experience that kangaroo populationsremain viable in the long term with harvests inthe vicinity of 8-10%, that is, at rates nowachieved routinely. In practice, particularlygiven the male-biased harvest, proportionalharvests even much higher than that would besustainable, although the offtake in numbers ofindividuals would be smaller, because of areduced population size. Mathematicalmodelling suggests that harvesting at 10-15%per annum, which occurs routinely in someareas, reduces average populations by 30-40%compared with what they would be if there were

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no harvesting (Caughley 1987a). Annualharvesting in the eastern States over the last 20or so years has been set at 10-15%, or higher, sothere has undoubtedly been a degree of successat “pest control”. In the absence of significantpredation from dingoes, the other major sourceof kangaroo mortality is starvation duringdroughts. If there were no harvesting, the

natural weather-driven boom-bust cycles inpopulations would be even larger than they are(Pople 1996, Grigg and Pople 2001).

In short, the fear expressed so prevalently in the1970s that kangaroos were being exposed to therisk of extinction by harvesting was, and is, simplynon-existent. However, the raising of thoseconcerns did have a positive outcome because a

Figure 2. Population trends, quotas and harvests in the South Australian Pastoral Zone since 1978 for (a) RedKangaroos and (b) Western Grey Kangaroos. Aerial surveys undertaken by Grigg and co-workers, funded byNational Parks and Wildlife SA. Figure updated from Pople and Grigg (1998).

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lot of research was stimulated and we now have avery significant body of hard information onwhich to base decisions about safe levels ofutilisation of kangaroos. 2. Animal rights and welfare issuesCompassionate approaches to the use of animalsfor food and clothing and the control of eruptivenative and animal populations are things whichdistinguish our civilisation. Australia facesmassive problems with populations of introduced,

now feral, horses, donkeys, camels, buffalo, deer,rabbits, hares, foxes and cats, quite apart fromlarge numbers of kangaroos and some wallabies asa result of anthropogenic changes in bioticconditions. The herbivores on this list are notbeing controlled by predation and, if notcontrolled in some other way, will causesignificant modification to our habitats, evenbeyond the massive changes which have occurredsince Europeans arrived. The predators (foxes and

Figure 3. Trends in combined State population totals, quotas and harvest offtake (in numbers and %) of EasternGrey Kangaroos, Red Kangaroos and Western Grey Kangaroos in the commercial areas. Extrapolations andinterpolations are shown as a dotted line. Figure updated modified from Pople and Grigg (1998).

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cats) have already modified our wildlife, andcontinue to do so. Seeking humane ways to effectcontrol over abundant native and introducedspecies continues to be a major activity for ourscientists and, even if ‘magic bullets’ arediscovered or invented, there may be real politicaland legal impediments to their application. So weconfront a very real dilemma in wishing to dealcompassionately with animals while, at the sametime, needing to prevent their presence becomingan ecosystem-threatening force.

Coming to terms with the use of animals for foodand clothing and for controlling pest species is amatter of finding an appropriate balance. Mostpeople come to a point of equilibrium in whichthey recognise the need for animals to be killedprovided, however, that individual animals aretreated in a humane way during their life, andkilled in a way which minimises or avoids suffering.

The harvesting of kangaroos has attracted plentyof adverse criticism and there will probablyalways be opposition from a minority of thepopulation. The expression of this opposition hasbeen beneficial because it has led to much morecare and attention being paid to ensuring thatslaughter is carried out humanely through theimplementation of the Code of Conduct. In afree and democratic society, which Australiansaspire to be part of, the right to freely express apoint of view is crucial. I prefer, however, thatparticipation in public debate is conductedhonestly and without personal attacks onindividuals. The Australian animal rights groupsdo not always adhere to that philosophy, asshown by a recent publication which is not onlyfull of untruths but is also very personal in itsattack (Wilson 1999). Many people choose notto eat meat, and the freedom to choose is surelyan important freedom to retain.

For me, the important issues about whether ornot to harvest an animal for meat are whetherthe animal population is put at risk by theremoval of those individuals, and whether thekilling will be done humanely. Only the secondconsideration is relevant to domestic stock, butboth are crucial for a wildlife harvest. Theharvest of wildlife seems to provoke particularopposition from many people who quite happilyeat meat from domestic stock. At one level I canunderstand this, because the culturalprogramming in westernised societies seems tomake wildlife sacred. Rationally, however, theissues remain the same and I think what I wrote

in 1984 is still applicable: “As to cruelty, theRSPCA has no major concern regarding professionalkangaroo shooters. Indeed one could argue that theslaughter of kangaroos is more humane than theslaughter of sheep and cattle, on the grounds thatkangaroos lead their normal existence as wild animalsuntil the last instant. On the other hand cattle andsheep are herded, jostled onto trucks and oftentransported long distances in hot conditions beforeeventually being killed” (Grigg 1984).

I know people who do not eat meat fromtraditional domestic stock because of thistreatment, and who seek out kangaroo meatinstead because it represents a philosophicallymore defensible “free range” harvest.3. Kangaroos as pests in competition withsheep The third major issue from the 1970s, thatkangaroos are a pest to woolgrowers, remainsvery much alive and is, if anything, even moreentrenched today even though there has beensignificant research activity. Views are polarisedon this issue. The main focus of controversy is theextent to which competition between kangaroosand sheep is injurious to economic production inthe wool industry. Since the 1970s there has beena lot of research. A survey by Gibson and Young(1988) quantified the extent to which kangaroosare regarded as pests by NSW pastoralists, but asyet there has been no quantification of the extentof lost production. One issue that has attractedattention has been the way kangaroos move to apaddock being spelled from sheep, attracted bythe green pick there, which compromises alandholder’s management options. This wasstudied by Norbury and Norbury (1993) whoexamined the possibility of controlling thekangaroos by turning off water supplies.

However, the main focus of interest has been onthe extent of competition by kangaroos for fodderwhich woolgrowers would prefer was used bysheep. Gibson and Young (1988) found thatlandholders’ perceptions were that about $55Mwas lost in fodder consumed by kangaroos, and itis clear that direct competition for food is seen asa major concern. Whether the perception ofmajor economic losses is real or not is a vexedquestion. McLeod (1996) and, more recently,Pople and Grigg (1998) have reviewed researchon Red Kangaroos in which experimentalapproaches have focussed on Fowlers Gap in thechenopod shrublands of NSW and at Lake Merein the NSW semi-arid woodlands. The Lake



Mere study (Wilson 1991) presented evidence ofdirect competition, but McLeod expressedscepticism about the results because of hisconcerns about the study’s experimental design,as well as the unrealistically high stocking rates inthe experimental enclosures. At Fowlers Gap,Edwards et al. (1995, 1996) found reduced sheeplive weights in the presence of kangaroos whenpasture biomasses were very low (<50-60 g/m2),but little evidence of competition above thisthreshold. McLeod (1996), following on at thesame Fowler’s gap study site, concluded thatdecreased wool productivity as a consequence ofcompetition from kangaroos occurred only inunusual circumstances, at very low pasturebiomasses and high kangaroo densities and,further, that the competition was asymmetric,with sheep dominating.

One fact which needs to be remembered is thatwhile sheep are contained behind fences,kangaroos are free to move out when conditionsdeteriorate. This was the case in the Fowlers Gapstudy, which therefore mimicked reality moreclosely. Indeed the capacity of kangaroos toredistribute themselves according to resourceavailability is a luxury denied sheep, but whichhas important implications for discussions aboutthe comparative roles of kangaroos and sheep asagents of land degradation.

More work needs to be done in a range ofhabitats, with careful attention paid toexperimental design and stocking rates, and forlonger terms because vegetation response in therangelands is notoriously slow. The slowrehabilitation of an overgrazed paddock atKoonamore in South Australia from which sheephave been excluded since 1925 (Sinclair 1996)stands as a striking example. So the comparativeroles of kangaroos and sheep in rangelandsystems still remains unclear, despite a lot ofresearch on kangaroos themselves. 4. Changed attitudes to land degradation,and to the role of kangaroos in causing itAlthough the extent of land degradation has notdecreased in the last 20-30 years, attitudes to itand to the role of kangaroos in it have changed.People were reluctant to talk about landdegradation in the late 1970s and 1980s, butthere is now a wide recognition of the extent ofland degradation in the sheep rangelands and awillingness to discuss it. This change in attitudecame 3-4 generations after land degradation wasrecognised and documented as a serious problem

by the Royal Commission on Western Lands(1901), of which Lunney (1994a, b) has provideda vivid preçis. In other words, it took longer toadmit to the problem than to cause it. One of thebenefits from the “Decade of Landcare” (the1990s) has certainly been that this and otherproblems of sustainability are now the frequentfocus of conferences and community activities.There has been a real cultural change, and thiswill probably be the biggest short-term outcomefrom the Landcare movement and its successor,the Natural Heritage Trust.

In contrast to the gradual acceptance of theexistence of land degradation and a willingness todiscuss it, there has been a shift in attitudestowards kangaroos so that kangaroos are nowregarded not just as competitors of sheep but alsoas significant direct causative agents in landdegradation. This is a view I now hear commonly.A recent example: “pastoralists generally arguethat [the kangaroo management programs] havebeen ineffective in controlling kangaroo impactson rangeland vegetation and pastoralproduction” (Hacker et al. 2000).

Whatever the cause, land degradation andfinding ways to reverse it has always been adriving force for me. My interest in finding aneconomic incentive that would encouragelandholders to run fewer sheep was stimulated bymy early aerial survey experiences in which I sawthe extent of land degradation. I wrote of thoseperceptions: “Most of the grazing lands,unfortunately, show everywhere abundant signs ofthe foot and tooth pressure of the introduced hard-footed stock and there is simply no room for doubtthat running sheep in the fragile arid inland has donea lot of damage. Graziers will argue that they obeythe stocking rates recommended and many of themdo, perhaps even most of them do. Maybe even all ofthem do, but the fact of the matter remains that thedamage is everywhere evident” (Grigg 1987).

This statement is equally applicable today. Onthe 24th annual aerial survey of kangaroos inSouth Australia in July-August 2001, I still sawhigh densities of sheep (and goats in manyplaces) and, looking over the barren terrain, I stillwondered what they found to eat.

A large part of the problem is that sheep inmarginal country producing coarse fibre wool areworth too little to be profitable at low densities(unless the property size is very large, supportingperhaps only one family). The overall trend hasbeen for the problem to worsen (whether or not

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the present improvement of wool prices with thelow Australian dollar will make a long-termimpact is unknown, but doubtful). With someups and downs (and a recent sharp rise, but forhow long?), average wool price fell from 969cents/kilo in 1990 to 550 cents in 1999 (ABARE)and they are much smaller cents if you allow forinflation. Along with this, Australia’s sheepnumbers have fallen from 173M to 115M(ABARE) as many growers have taken up cattle,cotton or other farming activities. [Of course,using average wool price data masks the realitythat the market has several distinct segmentswhich are moving in diametrically oppositedirections. The prices for coarse fibres haveessentially collapsed over the last 15 years (that iswhat was in the wool stockpile) but prices for fineand superfine fibres are good to excellent. Inother words, good low micron fleece, grown ingood conditions attracts a premium, but marginalcountry producing coarse fibres is less and lesseconomic. Most of the wool produced in thesheep rangelands is coarse fibre, low value, whichis being replaced increasingly by synthetics, and itis this landuse against which commercial use ofkangaroos competes.]

With unsatisfactory prices for coarse fibre wool, itis not surprising that resentment towardskangaroos has grown. When sheep were veryprofitable, as they were in the 19th century until1890, there was encouragement to carry a lot ofthem, but now it is falling prices that provide anincentive to put more sheep onto the land tomaintain income. Just as complaints about“plagues of kangaroos” are most common duringdroughts when forage is scarcest (and whenkangaroos are most noticeable feeding on greenpick close to roads), low prices for coarse woolalso raise the level of antagonism towardskangaroos and this has expanded to includeblame for land degradation as well as competitionwith sheep for forage.

Where are we now? On a pathtowards serious kangaroo control! In 1997 I wrote that Australia was at a crossroadsin kangaroo management policy:

“In one direction is the traditional view ofkangaroos as pests, which is leading to more andbetter ways to ‘control’ them. In the other directionis the view of kangaroos as a potentially valuableresource, which leads to a focus on more andbetter ways to market them and to have them bringsignificant economic value to landholders.”

I argued then that these two directions wereincompatible because significant reduction inkangaroo populations removed the potential for asignificant, continuing, long-term high-value,high-volume kangaroo industry and, thereby, thepotential to achieve conservation goals byreplacing large numbers of sheep with high-valuekangaroos. I asserted that “the only real,practical, long term direction at these crossroadsis the one leading to kangaroos as a sustainableeconomic resource”, which would “bring intoalignment...the ecological and economic goals inAustralia’s sheep rangelands” (Grigg 1997).

I still believe this to be the case, but it is clear thatthe official pathway remains mainly along theother road, towards getting more effective“control” of kangaroos. The wrong way at the crossroadsThere is no doubt that, for the present anyway,the official path is more towards kangaroocontrol than price-boosting, with the kangarooindustry being expected to deliver that control.New South Wales, Queensland and SouthAustralia are all looking at “more effective”kangaroo control. The Queensland Departmentof Primary Industries has a program, under LesterPahl’s direction, which is designed to work outbetter ways for woolgrowers to control kangaroosby using water traps to make pest reduction moreefficient. NSW Agriculture has a Murray-DarlingBasin Commission funded project, under RonHacker, entitled “Evaluating AlternativeManagement Strategies for kangaroos in theMurray-Darling basin”. This includes assessingthe capacity of the kangaroo industry to achieveparticular harvest rates and population densities,in tune with stakeholder concerns.

South Australia is furthest along the roadtowards implementing policies designed to lowerkangaroo numbers. The South Australianapproach since 1996 has been to look towardshigher proportional harvests as a tool forreducing kangaroo populations to less than halfthe long-term average populations. The 1999proposal to the Commonwealth for harvestquotas in 2000 identified a range of targetdensities in each of the Soil Boards. If the lowends of the ranges were to be achieved, and it isclear that these are the real targets, it wouldresult in a reduction of Red Kangaroos in SouthAustralia from a long-term average of 1.49million to 0.6 million, or a 60% decrease(Alexander et al. 1999). The target densities havebeen set in consultation with the Soil Boards, and



the Department of Environment and Heritage isclearly aiming to manage the populations inresponse to current landholder perceptions aboutappropriate numbers of kangaroos and their rolein land degradation and in compromising theeconomic viability of the existing industry,namely introduced stock, and especially sheep.

The notion of shooting a larger proportion ofkangaroos will be politically acceptable in thegrazing community but, unfortunately, there is noquantitative information which identifies thelevels at which kangaroo populations are‘acceptably benign’. I suspect that even at very lowdensities their capacity to concentrate on greenpick in a spelled paddock will still be the cause ofjust as much grief for landholders as whennumbers are higher. It may well be that the SouthAustralian approach is desirable both ecologicallyand economically. After all, experience in theFlinders Ranges shows that there can be nodoubt that grazing pressure at very high densitiesof macropods can have a conspicuous effect onpasture and land erosion by thwarting attempts atregeneration. However, whether reductions ofthis magnitude will actually make any noticeabledifference at the densities typical in SouthAustralia’s sheep rangelands is unknown and, as Iwill show later, extremely unlikely.

South Australia is endeavouring to embark onresearch to try to measure the effect of reductionsin kangaroo numbers in the continuing presenceof sheep, with appropriate experimental controls,and it will be interesting to see whether or notthere is reality in the long-held belief thatkangaroos have a seriously negative influence onfarm profits and land condition.

My own view is that kangaroos are often madescapegoats. I am unconvinced that it isappropriate, without good data, to adopt a policydesigned to halve a State or the national kangaroopopulation because of a belief that they areharmful at the diversities which are typical in thesheep rangelands. Indeed, there are good reasonsto suspect that even large reductions in numberswill have little or no effect. If, on the other hand,halving the kangaroo populations really does leadto measurable benefits to land conservation, thenI will be a strong supporter of doing so.

It is relevant to note that all three State programswere devised in consultation with landholders andother “stakeholders” at workshops, and all arelooking for ways to implement the requests ofwoolgrowers who regard kangaroos as pests. That is,

the programs are all “perception-driven” ratherthan “information-driven”. This direction has beenencouraged by a cultural change in governments’attitudes to “extension services”. We seem to haveentered a phase of management in many areas inAustralia where the policies of government agenciesare dictated by local “knowledge” which, thoughaccepted at a grass roots or stakeholder level, isoften too shaky to satisfy a scientist. In my view, theresponsibility of the scientist, government orotherwise, is to evaluate the accepted “knowledge”in a proper, evidence-based framework, and withthe degree of scepticism appropriate in all scientificenquiry, to publicise the results and, if they conflictwith the accepted knowledge, to say so loudly andoften in the belief that management based on truthis in the long run much more likely to beappropriate than management based onmisunderstanding. Further, I think it is theresponsibility of governments, through seniorbureaucrats, to back their scientists in theseactivities. Unfortunately this does not occur, andsome senior bureaucrats seem to only want to, orare only able to, tell their political masters what theythink their masters want to hear and, sadly, thesame goes for some scientists as well. This may leadto research and policy directions which are designedto find ways to implement the wishes of the“stakeholders” whether or not the desired goals areachievable or useful. It also leads to “publication” of“results” only in internal reports which are not peer-reviewed by independent scientists and are oftencirculated no more widely than the audience theyare designed to serve. I believe that there is a seriousneed for scientists to publish in appropriate journalsthe science on which they base their managementadvice so that other, independent, scientists canreview it. In the case of kangaroos, this process ofinternal reports has led to kangaroos being madescapegoats, even at a governmental level, eventhough the evidence that reducing kangaroos willlead to increased wool production is equivocal atbest. Existing evidence from the most realisticallyformulated empirical studies tends to exoneratekangaroos except in the driest times.

Uncertain results for woolgrowersWoolgrowers will not, I believe, get the benefitsthey want (better economic viability at lower totalgrazing pressures, or the capacity to carry moresheep) by reducing the number of kangaroos.

This is an important issue because millions ofdollars are being spent trying to work out how toachieve this objective. What outcomes do

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woolgrowers want? Most of all, they want improvedeconomic viability, preferably at lower total grazingpressure. Hacker et al. (2000) identified twoseparate ways in which kangaroos are believed tothreaten this aim: reduced wool production persheep and reduced carrying capacity.

It is my belief that reductions of kangaroos will notprovide the outcome/s woolgrowers and landmanagers want. This is an opinion, but it is aninformed one. It is an opinion which flies in theface of the assumptions underlying the directionthat kangaroo management now appears to betaking. It is an opinion that few will want to hear.Most people in the kangaroo industry will notwant to hear it because a long standing rationalefor permitting this large harvest of wildlife hasbeen the assumption that kangaroos are a pest towoolgrowers. Most woolgrowers will probablyreject it as just more raving from “another one ofthose academics in the city”. Many people ingovernment agencies, such as agriculture andprimary industries, will not want to hear it either,partly because their focus is primarily ontraditional rather than potential new industries,partly because of their traditional alignment withpeople in the traditional industries, and partlybecause now that such agencies are increasinglyexpected to be financially self-sufficient it isdifficult for them to be in any vanguard for change.

My opinion, my “working hypothesis”, should beevaluated by research, not simply rejected bycounter-opinion or dismissed by the production ofalternative views. I have been trying withoutsuccess for years to get funding for a properresearch effort. Fortunately, there is a growingbody of concerned biologists – both in governmentand in the universities – and open-minded landmanagers who are willing to adopt new ways ofmeeting the challenge of land restoration.

Why do I believe that there will not be muchbenefit from reducing the size of kangaroopopulations? For several reasons, but I cannot yetput good science to it any more than theproponents can support their contentions. Thetruth of the matter is that the results of empiricalstudies which have striven to assess the extent ofcompetition between kangaroos and sheep havetended to exonerate kangaroos. More work isneeded, but there seems to be an unwillingness toaccept that this could be true and, instead, tocontinue to interpret or model information in away which leaves kangaroos as the villains.

One study which seeks to advance the state ofknowledge in this area is a desktop study by

Hacker et al. (2000), which uses the results ofempirical studies combined with a number ofassumptions to conclude that, in the mulgawoodlands of Queensland, harvesting kangaroosat 10% per annum would lead to an increase inwool production of up to 25%. This is close to theannual harvests that have been taken from thisarea, so the implication is that current woolproduction is up to 25% higher as a consequenceof the current harvests of kangaroos. Conversely,the implication is that wool production is now upto 25% lower on properties where kangarooshooting is minimal.

I think it extremely unlikely that this conclusioncould be correct, particularly in the face ofinformation (admittedly from a different habitat,the chenopod shrublands) gained by McLeod(1996) and Edwards et al. (1995, 1996). Onedifficulty in the analysis is that their modelassumes average body weights for kangaroos,which are too high (30 kg), and the sensitivity ofthe outcome to this assumption was notpresented. If models, rather than empiricism, areto be used as the basis of management decisions,then it is important that the models are asrealistic as possible. Such models must includerealistic values for the comparative foragerequirements of kangaroos and sheep, which takeproper account of differing body weights andmetabolic requirements. Comparative forage requirements ofkangaroos and sheepIn assessing the comparative contributions of sheepand kangaroos to TGP (Total Grazing Pressure),the amount of pasture required by a kangaroo isusually assumed to be 0.7 of a DSE (dry sheepequivalent). This value (or sometimes 0.75) isapplied routinely, (for example, see the QueenslandDPI website at http://www2.dpi.qld.gov.au/dpinotes/animals/sheep/sw97007.html) but it isundoubtedly incorrect, perhaps even wildly so.From the QDPI website, sheep are said to require400kg of forage per year, kangaroos 280kg (400 x0.7). A DSE is equated as forage consumed in oneyear by a 45kg (Merino) wether (a “wet” Merino,one with a lamb, equates to 1.5 DSEs, and cattle10-12). Thus, in terms of forage lost from whatwould have been available for domestic livestock,1,000 kangaroos are equated to 700 “dry” sheep.

Using such a simple translation assumes thatsheep and kangaroos share a common food pooland ignores any spatial differences in theirforaging habits. However, leaving that completely


A Zoological Revolution

aside, there are two other reasons that thisequation is flawed. One is to do with comparativepopulation biomasses and the other is with theorigin and meaning of the value 0.7.Nevertheless, the multiplication of estimates ofkangaroo numbers by 0.7 and equating that toforage lost in terms of DSE has become firmlyembedded in rangeland ecology lore. Let usexplore the inadequacies of this practice.

Firstly, multiplying by 0.7 does not take intoaccount the different sizes of sheep andkangaroos. Where sheep are being grown forwool, stock management leads to flocks of adultswith a reasonably homogeneous age and sizedistribution, and in calculations of TGP theinputs relate to sheep with a body weight of 45kg.In contrast, many individuals in kangaroopopulations will be much less than this. Forexample, Stuart Cairns from the University ofNew England is conducting a long-term study atBulgunnia in South Australia, where male andfemale kangaroos are harvested in approximatelysimilar proportions. Excluding pouch young, onlyabout 25% of the male Red Kangaroos and 45%of the females in 1998 and 1999 were more than3 years old (Cairns pers. comm.). Both sexes areapproximately 8-10kg at 1 year, 17-20kg at 2years and 21-32kg at three years. With sexualdimorphism becoming more developed in olderanimals, females older than three years mightaverage 28-30kg, males 45-55kg. Therefore, inthe Bulgunnia population, two thirds of theindividuals would be smaller than 20kg. This islikely to be typical of a harvested population.

The range of sizes present in typical kangaroopopulations clearly complicates estimation of apopulation’s forage requirements from estimatesof raw numbers. However, Tony Pople at theUniversity of Queensland has provided someaverage values for the purpose of making simple,illustrative calculations. Unharvested kangaroopopulations can be expected to have a meanbody weight of about 32kg (South Australia) and27kg (Queensland), and harvested populationsto have means of 19kg (SA) and 16kg (Qld)respectively (Pople pers. comm.). We cancalculate weight-corrected values for DSE usingthe generalisation about the way in whichmetabolic rate (and thus forage requirement)scales with body mass, i.e. MR a M0.75. (This willbe familiar to many readers as the famous‘mouse-elephant curve’.) Applying this to thetraditional assumption that a kangaroo has aforage requirement of 70% that of a sheep leads

to DSE values of 0.54 (in unharvestedpopulations) and 0.37 (harvested populations) inSouth Australia, and 0.48 (unharvested) and0.32 (harvested) in Queensland. Kangaroopopulations on sheep properties tend to beharvested rather than unharvested, and thesevalues are vastly different from 0.7.

There are some measurements of kangaroo forageintake from work done by Short (1985, 1987) withwhich these theoretically derived estimates can becompared. He measured the relationship betweenfood intake and food availability in graze-downtrials with Red Kangaroos and sheep (and rabbits).He compared replicated pairs of 20x20 m pens,with two individuals in each, assessing food intakeby following the decline in biomass measured dailyby visual estimates in quadrats, using a series ofreference photographs. The kangaroos and sheepconsumed 65g/kg0.75/day and 80g/kg0.75/dayrespectively when food was not limiting. Takingscaling into account, this implies that suitable DSEvalues would be 0.62 (in unharvested populations)and 0.42 (harvested populations) in SouthAustralia, and 0.54 (unharvested) and 0.37(harvested) in Queensland Tony Pople pers.comm.). These values are 11-13% higher thanthose I calculated from theoretical considerations,averaging 0.4 in a harvested population comparedto 0.35. There could be a simple explanation forthis difference (see below) but, either way, it isclear that body mass considerations cannot beignored in calculating the kangaroo component ofTGP. If DSE is 0.35-0.40, it is harder to see howhalving the numbers of kangaroos on the averagesheep property would make much difference towool productivity, or to reducing land degradation.

However, the failure of the assumptions behindthe 0.7 figure gets worse, because there are goodreasons to think that kangaroos require evenless than 70% as much forage as equivalent-sized sheep. The value 0.7 comes from theresting metabolic rate of marsupials being about70% of eutherian mammals of equivalent weight(Dawson and Hulbert 1970) and therecognition that forage requirements correlatewell with metabolic needs. However, animals donot spend their lives at rest, and physiologicalecologists use the term “field metabolic rate”(FMR) to refer to the overall metabolicrequirements of an animal in its natural habitat,including that required for foraging and otheractivities. So a much more valid approachwould be to use a DSE ratio which reflects theFMRs of sheep and kangaroos, rather than their

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resting rates, and when this is done there is avery different result. Metabolic rates can bedetermined in free-ranging animals bymeasuring rate of turnover of doubly-labelledwater, which enables the measurement ofcarbon dioxide excretion, which can be relatedvia respiratory quotient (RQ) to oxygenconsumption (Lifson and McClintock 1966,Nagy 1980). In this way, generalisations havebeen determined empirically for a large numberof eutherian and marsupial mammals over alarge size range, and very good correlations werefound in both groups (Nagy 1987). Nodistinctions emerged between the groups atsmall sizes (<1 kg). However, large differenceswere found between marsupials and eutheriansover a size range from 20-50kg, where the FMRof eutherians such as sheep was found to be 3-3.5 times that of marsupials such as kangaroos.This suggests that the DSE for kangaroos thesame size as sheep should be of the order of0.29-0.33 and not 0.7. Why this should be so isnot obvious, but cannot be ignored.

Fanning and Dawson (1989) also measured FMRin Red Kangaroos, but using a completelydifferent approach (radiotelemetry of heart rateas an index of oxygen requirements) and foundan essentially similar result. Their measurementsof three individuals free-ranging in a 100-hectareenclosure averaged slightly lower than thatpredicted by Nagy’s generalised equation,suggesting a DSE equivalent (for animals of thesame size) in the vicinity of 0.25. They too wereclearly intrigued by the low result, and speculatedon what it is about marsupials that apparentlyenables them to operate so efficiently.

These observations are thought-provoking, and itseems highly likely that the energeticrequirements of free ranging kangaroos are farless than what has been accepted for sheep thesame size.

Putting these two lines of thought together —comparative population biomasses andrecalculated forage requirement ratios — we canpropose that the “rule of thumb” for translatingkangaroo numbers to DSE for the purpose ofcalculating the kangaroo component of TGP in aharvested population should be about 0.15-0.2;that is, an average kangaroo in a harvestedpopulation (16-19kg) requires only 15-20% ofthe forage of an average (45kg) sheep. This ismuch sharper contrast to the empirical datapresented by Short (1987). However, graze-downtrials on a small number of kangaroos in a penover a short time frame cannot be said to bedefinitive. For one thing, food was plentiful andthey may have been taking an opportunity toincrease body condition. Also, perhaps in a smallpen they were constrained to a pentapedal gait,their most inefficient form of locomotion(Dawson 1973). A DSE of 0.15-0.20 would seemto be unlikely. However, in the face of twocompletely independent studies turning up suchsimilar answers by different techniques, thatpossibility cannot be dismissed. Obviously thereis a need for more empirical data to be gathered,under realistic conditions.

These considerations raise the importantquestion: by how much would kangaroo numbersneed to be reduced to make a measurabledifference? Apart from the real value of theequivalence between sheep and kangaroos, therelative numbers of the two herbivores on aproperty is a real consideration. Hacker et al.(2000) reported that, historically, the kangaroopopulation in the Western Division of NSW hasranged from 45-60% of the domestic livestockpopulation, expressed in terms of dry sheepequivalents using a DSE of 0.75. A typicalproperty might therefore be said to have about2/3 as many kangaroos as sheep. Table 1 presentsa comparative assessment of the contribution to

DSE represented by each kangaroo Contribution to “TGP” by kangaroos on a property with 10,000 sheep and 6,660 kangaroos

0.7 (traditional value) 32% 6,660 ‘roos = 4,662 sheep,TGP = 14,662 sheep

0.4 (comparative biomasses considered) 21% 6,660 ‘roos = 2,664 sheep,TGP = 12,664 sheep

0.2 (comparative free-ranging MRs considered also) 12% 6,660 ‘roos = 1,332 sheep,TGP = 11,332 sheep

Table 1. On the basis of comparative biomasses and field metabolic rates this paper asserts that 0.7 is too largea value for DSE, and shows that there are good reasons for suggesting that a value even as low as 0.15-0.2 mightbe more appropriate. If this were correct, removing half the kangaroos from a property with 10,000 sheep and6,660 kangaroos would reduce the total forage offtake by only 6% compared to the 16% benefit suggested byusing a DSE of 0.7.



TGP made by kangaroos on such a propertyaccording to the three different DSE valuesdiscussed above; the “traditional” 0.7; 0.4 (beingconservative) derived by taking the smaller sizesof kangaroos into account; and 0.20 (still beingconservative) taking the comparative FMRs intoaccount as well.

The other side of this coin, of course, is that ifkangaroos got to be seriously valuable, removingsheep would allow a larger number of kangaroos tobe carried, and there would have to be goodregulation and effective harvests to ensure thatland degradation is not exacerbated. If nothingelse, the table makes it clear that having a goodestimate of an appropriate value for the DSE isimportant before any meaningful conclusions canbe drawn about how much benefit can beexpected from the reduction of kangaroo numbers.

One quite worrying potential mis-application ofthe “traditional” value for DSE is that, ifkangaroo numbers are reduced by a knownnumber, a wool grower might then feel itappropriate to increase sheep to accommodatethat reduction, calculated using the 0.7 figure.Hacker et al. (2000) made it quite clear that theyhad in mind getting an increased carryingcapacity for sheep, rather than achieving landrehabilitation from kangaroo reduction, whenthey point out that apart from the up to 25% gainin wool production which (they claim) flows froma 10% kangaroo harvest, “the impact of kangarooson resource management is potentially moreimportant than the effect on per head production dueto the greater potential to increase pastoralproductivity through increased carrying capacity”.

This is breath-taking. Just imagine if a targetreduction of 60% were achieved, as identified inSouth Australian, and landholders felt justified inincreasing sheep accordingly. To make the pointagain about the importance of using a realisticDSE for kangaroos, if a reduction in kangaroos by60% were achieved on a property with 10,000sheep, at present reckoning this would beequated to forage for an additional 2,797 sheep(0.6 x 4662; DSE 0.7). If the real value were 0.2however, adding 2,797 sheep would lead to anincrease in TGP from 11,332 DSE to 13,329, anearly 20% increase in TGP when the landholdermay think he/she is level pegging!

For these reasons, we need better informationabout appropriate DSEs for kangaroos if therangelands are to be managed both optimally and sustainably.

These considerations of comparativecontribution to TGP by kangaroos and sheep,however, consider TGP only in terms of theactual forage requirements, that is, kg of pastureconsumed. There is another aspect of TGP whichrarely gets a mention and that is the pressurefrom the direct, physical effects of tooth and footpressure on rangeland soils and plants.

Hard-footed v. soft-footed

The notion of comparing kangaroos with sheepon the basis of their comparative foragerequirements, with a rule of thumb equivalence,is a good one. However, forage requirements areonly part of the impact made by foragingherbivores on the pasture. They also make aphysical impact on the plants in the way theyfeed and the way they walk over the landscape.These are the tooth and foot pressurecomponents of total grazing pressure. Currently,rangeland ecologists do not take this intoaccount and, in fact, assume that there is nodifference between sheep and kangaroos in theabrasion and compaction to which the plants andsoils are subjected as part of the foraging process.There is, for example, no consideration allowedfor this in calculations translating kangaroos tosheep equivalents.

The omission is an interesting one though,because the belief is often expressed by Australiansat large that kangaroos are soft-footed andtherefore do less damage to the landscape thansheep. I have heard this expressed time and timeagain as a good reason to eat kangaroo meat, frompeople who live in the city and have no vestedinterest in the matter. However, as Noble andTongway (1986) noted, “supporting data for thisfolklore is deficient” and there appears to be no soliddata which helps in any discussion about whethersheep are harder on the land. In the past I haveasserted that they are (Grigg 1987), but I wasquickly reminded of the lack of data, so I stoppedasserting it, but not thinking about it. Absence ofevidence is not evidence of absence, and we needto know more about this question, especially if, ascurrent official thinking seems to imply, there isgoing to be a national push towards furtherreductions in kangaroos.

There is now a small amount of data oncomparative foot pressures. Noble and Tongway(1986) tabulated data which show that sheephave a somewhat higher (1.9-2.6 kg/cm2) staticfoot pressure than kangaroos (0.8-1.8 kg/cm2).More recently, Bennett (1999) investigated “foot

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areas, ground reaction forces and pressuresbeneath the feet” of a range of 23 species ofmacropods and came to the conclusion that “thefindings support the commonly held belief thatintroduced grazing animals may cause greatermechanical disruption of the soil surface, leading toincreased rates of soil erosion, than Australia’sindigenous grazing fauna”.

However, a more comprehensive study is needed.If I had to make an assertion, which might be theworking hypothesis, based on the data on footpressures, on what can be seen from the air, onwhat is known about the movements of kangaroosand sheep in paddocks, and their use of water, andthe way sheep flock together and are restrained inpaddocks, it would be that kangaroos do lessdamage per head to soils and vegetation than dosheep, at similar, typical densities.

Taken together, these considerations aboutrealistic values for DSE, comparative biomasses,and kangaroos probably having lesser physicalimpacts than sheep on soils and vegetation allowthe conclusion to be drawn strongly thatwoolgrowers will not get the benefits they seekfrom reductions in kangaroo numbers.

The medium-term and long-term futureDespite this, the current “official” thinking seemsto be enshrining kangaroos as pests rather than asa resource, which looks bleak for the idea ofachieving a conservation benefit from a high-valuekangaroo industry to provide woolgrowers with away to maintain their properties and lifestyles in anecologically benign way. The drift instead seems tobe to expand the use of the kangaroo industry inits traditional pest control role.

Therefore, in the medium term, we can expect to seea continuation of the expectation that reducingkangaroos, if it could be achieved, would be a bighelp to woolgrowers. The formal identification ofkangaroo reduction as a legitimate goal seems to bemuch closer than it was previously, through thecultural change which now sees governments morefocused on achieving politically acceptable,“stakeholder” driven goals than on achieving real,long-term sustainable outcomes. (In this context,“stakeholder” means a limited sample, too often onlylocal graziers or catchment management boards andtheir allies in the government departments set up tosupport and regulate them, but certainly not arepresentative sample of interested parties with alegitimate voice in the debate.)

As the kangaroo industry will be unable toharvest enough kangaroos (at current prices) toachieve the ambitious reductions in kangaroonumbers, I fear that the blame for landdegradation will now widen to include blamingthe kangaroo industry. After all, the presentquotas are seldom taken, so taking quotas largeenough to achieve a 60% reduction in kangaroosis a pipe dream. Only if kangaroo markets expandand prices rise to the extent that the full quotasare taken will landholders probably start takingthe serious interest in kangaroos that I have beenadvocating, and nobody will then be talkingabout the need for a 60% reduction.

It is interesting to speculate about the likelyimpact this might have on the current kangarooindustry. The industry is apparently comfortablein its present “pest control” role, and welcomesclaims such as those made recently by Hacker etal. (2000) which reinforce the idea that kangaroosare pests. This is made clear in the followingextract from a recent KIAA Newsletter (Volume21) referring to Hacker et al.’s (2000) report.

“Enormous Political Importance for theKangaroo Industry

…This is probably the first time a scientificanalysis has delivered a comment on the potentiallong term effect of kangaroo harvesting on sheepproduction economics. The computer modelsuggests that long term harvesting at ‘maximumsustainable yield’ (calculated to be 10% ofpopulations; that is, about the current quota levels)in Mulga country, may yield up to an extra 25%more wool to graziers for no extra costs. Noanalysis has yet been run, but such a benefit wouldhave an enormous impact on pastoral properties’bottom lines. Nor has any physical trial confirmedthat such a benefit is actually delivered.

However this computer simulated suggestion is ofenormous political importance to the kangarooindustry. It suggests that kangaroo harvestingprovides a direct and important (potentially huge)economic benefit to pastoralists. There are ofcourse many assumptions in creating this model(some of which may prove not to be correct), alsothe estimate carries two clear caveats:

1) It probably represents the upper limit of perhead productivity gains achievable, and

2) It relies on kangaroos being harvested atmaximum sustainable yield, which is about 10%of the total population.



However back of envelope calculations based onthese estimated gains suggest that it is possibleevery kangaroo harvested in the mulga woodlands,in an industry operating continually at maximumsustainable yield, could deliver a long run benefitin wool production worth more in dollar valuethan the actual value of the unprocessed kangaroosthemselves. That is, much more than pastoralistscould ever hope to be paid in any sort of ‘royalty’for the animals harvested on their properties. Inaddition we don’t as yet have an estimate of theproductivity benefit from kangaroo control in areasother than the mulga woodlands. It may well bethat when the benefits from increased woolproductivity nationally is calculated and added tothe value of kangaroo product, a kangarooindustry harvesting at maximum sustainable yields(about 10% of population) nationally would infact be worth half a billion dollars or more per yearto the economy!!!

Finally the authors of the above paper also note:“Nor does the model account for the [cost of]resource degradation that could be expected in thepresence of an unharvested kangaroo population.”

It appears that there are some in the kangarooindustry who may not have realised theimplications of successful kangaroo reduction;the long-term survival of the industry at itspresent size depends upon there being plenty ofkangaroos. And the socio-economic impacts of acollapsed kangaroo industry should not beunderestimated. Several towns in Queenslanddepend very heavily on it. The outcry inQueensland in 1995, when the governmentrefused to increase the quotas as it becameanticipated that by about August the quotaswould be fully taken, should not be forgotten.

Large numbers of kangaroos would be assured,however, if kangaroos were to become valuable(assuming a continuation of the present tightregulation over harvests), and instead of calls bylandholders for reduction there would be anemphasis on maintaining a maximum butsustainable yield. In that event, however, it isunlikely that landholders would continue to givethe kangaroos away as they (mostly) do now, andwe could expect changes in industry ownership aslandholders invest and become a force in arestructured kangaroo industry. This wouldprovide the opportunity for a conservation gain,if economic considerations encouragedlandholders into kangaroos, so let us turn ourattention to some of the marketable attributes ofkangaroos, particularly the meat.

How to make kangaroo meatmore valuable Important background information relevant to amarketing campaign to put kangaroo meat onthe world’s game meat market includes thefollowing considerations:

• At present the main commercial value ofkangaroos comes from their hides. Kangarooleather is thin but very strong and is ideal forshoes, including soccer boots and other sportsshoes. A rapid increase in the volume or pricein this market is unlikely because manu-facturers can turn to cheaper leathers such ascalf when shortages lead to price rises.

• Australia has a monopoly on the commerc-ialisation of kangaroo products.

• The proportion of kangaroos shot for theirskins alone is trending downwards, from morethan half a few years ago to less than 15% now(John Kelly, KIAA pers. comm.). OnlyQueensland has a legal skin-only take, butthis now equates to less than half the totalannual harvest. Most of the kangaroo meatharvested annually is used for pet food, butthe proportion used for human consumptionis rising steadily, approximating 20% in 2000.

• Marketing kangaroo meat is an exercise inselling a product which is already harvestedbut, because its value is so far largelyunrecognised, is mostly wasted or sold toocheaply.

• Local and overseas demand for kangaroo meatfor human consumption is rising slowly, as aresult of the activities of the KIAA and thebroader and growing official and publicacceptance of the principles of sustainable useof wildlife for conservation.

• At present, the value of kangaroo products isnot high enough to ensure that the annualquotas are fully taken, and prices cannot beexpected to rise until the annual quotas aretaken fully — that is, when supply exceedsdemand. However, an increased demand (forskins) in 1997 led to higher skin prices and anear full take of the quotas in the eastern States.

• A way forward from this Catch 22 situationwould be to generate an increase in demandby expanding the market for meat. Because ofcarefully set quotas, the supply is finite anddemand would not have to rise much for thequotas to be reached. It would be reasonable

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to expect a sharp price rise when demand risesto a point where the quotas are restrainingharvests on a regular basis; this would be aclassic vertical supply curve that wasinsensitive to increased demand.

• A 15% annual quota implies the availability ofabout 60,000 tonnes of meat (Switala 1995),varying from year to year as kangaroopopulations fluctuate in response to rainfalland pasture availability.

• Unlike most primary produce, the amount ofkangaroo skins and meat that will be availablein the following year will be known at the endof the previous year when the quotas are set.This allows primary producers and processorsto enter into supply contracts well ahead. In1997 we saw the beginnings of this in SouthAustralia, where tags were allocated toindividual properties, with some processorsentering into contracts with landholders earlyin the year to ensure a supply later on.

• In my opinion the logical way to expand themarket would be to sell kangaroo meat as aspecialty product in those countries wherethere is a history of appreciating game meats,such as in parts of Europe and in the USA plus,of course, as a restaurant meat in Australiawhere it has already made significantpenetration. I have never thought that localdomestic sales would be more than a small partof the market, like duck and venison. However,health benefits for cardiac fitness, itsphilosophical attraction as a free-range meatand freedom from BSE could mean that I amunderestimating this market potential.

• It follows that in a future, high-value industryall harvesting would be at human consumptionhygiene standards instead of the dual harvestingsystems we now have with some kangaroosbeing shot only for pet food. Then, the best cutsfrom all animals could enter the humanconsumption food chain, with the less choicecuts going for pets and other applications, as inthe current domestic meat industry.

• The development of a smallgoods industrybased on kangaroo meat is in its infancy, butthe products already available show thepromise of great potential.

With all of this in mind, I list below some of the factors useful for a marketing campaign. It is worth remembering that an advertisingcampaign for kangaroo meat is also a public

education campaign, because the concept ofharvesting wildlife for a conservation gain is notwidely understood or accepted throughout thecommunity. Getting that message across wouldbe an important element of any advertisingmessage.

Hence the following suggestions:

• Publicise the problems Australia has with landdegradation from overgrazing by sheep and thebenefits of a shift to a more kangaroo-basedland use, instead of reducing kangaroos inorder to carry even more sheep.

• Explain the concept of receiving aconservation gain from the commercial use ofkangaroos, the checks and balances in place toensure sustainability of the populations, andthat harvesting is undertaken hygienically andhumanely.

• Point out that harvesting free-range kangaroosis philosophically akin to free-range eggs,poultry or bacon. I am not advocating kangaroo“farming”, because neither restraint norhusbandry is envisaged. Indeed, I think thatwildlife authorities should specifically prohibitfarming and all it entails. Under what isproposed, a kangaroo remains as free-livingwildlife in its natural habitat until harvested.

• Of the harvesting itself, explain that “thepaddock slaughter of an animal unaware ofdanger” is more humane than the way we treatour domestic livestock. I know of people whowill not eat pork, beef or lamb because ofdiscomfort about the methods of husbandryand slaughter, but who approve of eatingkangaroo, and do so.

There are also many positives to do with themeat itself:

• Taste. Similar to beef but sufficiently differentto be interesting.

• It is healthy in having low fat (1-2%) and lowcholesterol (O’Dea 1988, Sinclair 1988) andis sometimes recommended for cardiacpatients taken off traditional red meat.

• There are no insecticide residues in the meatas kangaroos are not drenched or dipped likedomestic stock.

• No possibility of BSE. This might assist salesof the meat in Europe in particular.

• It is a traditional Aboriginal food which hasbeen a dietary mainstay throughout much ofthe continent for millennia.



The wrong way at yet anothercrossroads?There is underway in the rangelands of WesternAustralia, New South Wales and Queensland aquite different form of sheep replacement. This isthe shift to goats. There is growing interest in anda surprising amount of governmental support forwoolgrowers going into goats not just as ‘moneyin the bank, stored in the back paddock until theprice is right’ but as a serious ongoing enterprise.There seems to be a serious belief that goats willnot cause land degradation problems “as long asthey are controlled” (like sheep, I suppose). Thisshould be the subject of another essay, but sufficeit to say that if the wool industry is replaced by anindustry producing goat meat, then the furtherdesertification and degradation of the rangelandswill surely follow.

An increase in the value of kangaroo productsand a consequent shift in focus from sheep (andgoats) to kangaroos, the implementation ofwildlife and outdoor-based tourism and everyother ecologically benign diversification we canthink of will not come quickly enough to save therangelands if the emerging goat industry takes off.

The next 20 yearsIn the mid-1980s I thought that kangarooharvesting as a mechanism to allow sheepreduction and the consequent conservationbenefit was an idea whose time had come. I waswrong about the time frame, because Iunderestimated how long it takes for new ideas tobecome embedded, and for things to change. Inthe 1990s I accepted this, and became morerealistic. Now, in the 2000s, unless the goats win,I am even more convinced about the value of theidea and optimistic about its potential forachieving good conservation, social andeconomic outcomes in the long term. A lot ofthings have changed in the area of wildlifeconservation and management in the last 20years, and most of them are in directions whichmakes the implementation of “sheep replacementtherapy for rangelands” more likely. Theproportion of kangaroos shot for humanconsumption is rising steadily, prices are higher,people have a much better understanding now ofthe potential for harnessing economic imperativesin the service of conservation, and when annualharvest quotas are taken this stimulates price risestowards the point where landholders will looktowards kangaroos as a resource instead of a pest.

I still think that the impediments are notecological, but economic, and that the wholescene will change dramatically once the marketpotential is recognised.

The idea is being grasped and promoted by theAustralian Museum, which is embarking on aproject linking the concept of sustainable use ofwildlife for conservation gains to the more specifictarget of enhancing biodiversity. This project willinitially address kangaroos, embracing theconcepts outlined above, that have been throughthe long process of scientific and public debatefrom Cunnamulla to Canberra. Specifically, theMuseum’s project aims to monitor changes inbiodiversity in response to landholders shiftingfrom sheep to native wildlife. To dramaticallyrepresent this project, it has been dubbed FATE(Future of Australia’s Total Ecosystems) todemonstrate that taking a new approach toconservation is essential, not optional. Whether ornot FATE is able to accelerate what I see as thenatural progression now under way, in advance ofhigher values for kangaroo products, remains to beseen. But the fact that scientists and landmanagers are embracing these concepts andseeking to promote them is a very healthy sign.

Many of the people who now adhere to theparadigms which dictate our use of the sheeprangelands will not be the predominant forces inanother 20 years. I sense that new generations ofland managers and rural communities are goingto take rehabilitation of land far more seriously,and that they will be much more interested inpragmatic, ecologically sustainable and locallycompatible solutions.

The achievement of conservation goals throughthe sustainable use of wildlife depends onachieving an alignment of economic andecological goals. Gaining conservation benefitsfrom sustainable use is now a major newparadigm in wildlife management, a conceptwhich I have been pursuing since before theywere put into now-familiar words.

After nearly 25 years, and seeing countlessthousands of individual kangaroos, I still getpleasure from seeing another group ahead standup to listen quizzically to the sound of the aircrafton survey, or seeing them break into thatfantastic loping gait. If we cannot do somethingpositive about the continuing desertification inour arid and semi-arid lands, future generationswill not be able to enjoy the thrill of seeing thelarge numbers of kangaroos we now have.

Grigg


AcknowledgmentsI am grateful to Dan Lunney for his strongsupport and encouragement over many years, forpersuading me to write this and for making manyhelpful comments on the manuscript. I also wish

to thank the following people who madecomments on all or parts of the manuscript: IrinaDunn, Ron Hacker, John Kelly and Tony Pople(who also provided the figures).

ReferencesAlexander, P., Last, P. and Arnold, C. 1999.Kangaroo harvesting quotas – South Australia.Unpublished internal document referred to withpermission. National Parks and Wildlife, SouthAustralia. (obtainable on request)

Arnold, S. 1988. The morality of harvestingkangaroos. In “Kangaroo harvesting and theconservation of arid lands; a symposium” (Eds D.Lunney and G.C. Grigg). Royal Zoological Society ofNSW, Mosman. Pp.143-6. Australian Zoologist 24 (3):121-93.

Bennett, M.B. 1999. Foot areas, ground reactionforces and pressures beneath the feet of kangaroos,wallabies and rat kangaroos (Marsupialia:Macropodoidea). Journal of Zoology (London)247:365-9.

Calaby, J.H. and Grigg, G.C. 1989. Changes inmacropodoid communities and populations in the past200 years, and the future. In “Kangaroos, Wallabiesand Rat-Kangaroos”, Vol. 2. (Eds G. Grigg, P. Jarmanand I. Hume.). Pp.813-20. Surrey Beatty and Sons,Sydney.

Caughley, G., Grigg, G.C. and Short, J. 1983. Howmany kangaroos? Search 14: 151-2.

Caughley, G. 1987a. Ecological relationships. In“Kangaroos: Their Ecology and Management in theSheep Rangelands of Australia” (Eds G. Caughley, N.Shepherd and J. Short.). Pp.159-87. CambridgeUniversity Press, Cambridge.

Caughley, G. 1987b. Introduction to the sheeprangelands. In “Kangaroos: Their Ecology andManagement in the Sheep Rangelands of Australia”(Eds G. Caughley, N. Shepherd and J. Short.). Pp.11-13. Cambridge University Press, Cambridge.

Croft, D.B. 2000. Sustainable use of wildlife inwestern New South Wales: possibilities and problems.Rangeland Journal 22(1): 88-104.

Dawson, T.J. and Hulbert, A.J. 1970. Standardmetabolism, body temperature and surface areas ofAustralian marsupials. American Journal of Physiology218: 1233-8.

Dawson, T.J. and Taylor, C.R. 1973. Energetic costof locomotion in kangaroos. Nature 246:313-4.

Edwards, G. P., Croft, D. B. and Dawson, T. J. 1995.The dietary overlap between red kangaroos (Macropusrufus) and sheep (Ovis aries) in the arid rangelands ofAustralia. Australian Journal of Ecology 20: 324-34.

Edwards, G. P., Croft, D. B. and Dawson, T. J. 1996.Competition between red kangaroos (Macropus rufus)and sheep (Ovis aries) in the arid rangelands ofAustralia. Australian Journal of Ecology 21: 165-72.

Fanning, F.D. and Dawson, T.J. 1989. The use ofheart rate telemetry in the measurement of energyexpenditure in free-ranging red kangaroos. In“Kangaroos, Wallabies and Rat-Kangaroos”, Vol. 1.(Eds G. Grigg, P. Jarman and I. Hume.). Pp.239-44.Surrey Beatty and Sons, Sydney.

Fletcher, M., Southwell, C.J., Sheppard, N.W.,Caughley, G., Grice, D., Grigg, G.C. and Beard,L.A. 1990. Kangaroo population trends in theAustralian rangelands, 1980-87. Search 21: 28-9.

Gibson, L.M. and Young, M.D. 1988. “Kangaroos:Counting the Cost. The Economic Effects ofKangaroo Culling On Agricultural Production”.CSIRO, Melbourne.

Grigg, G. 1984. Roo harvesting. Are kangaroos reallyunder threat? Australian Natural History 21: 123-7.

Grigg, G.C. 1987. Kangaroos – a better economicbase for our marginal grazing lands? AustralianZoologist 24: 73-80.

Grigg, G. 1988. Kangaroo harvesting and theconservation of the sheep rangelands. In “Kangarooharvesting and the conservation of arid lands; asymposium” (Eds D. Lunney and G.C. Grigg). RoyalZoological Society of NSW, Mosman. Pp.124-8.Australian Zoologist 24(3): 121-93.

Grigg, G.C. 1997. A crossroads in kangaroo politics.Australian Biologist 10: 12-22.

Grigg, G.C., L.A. Beard, G.J. Caughley, D. Grice,J.A. Caughley, N. Shepherd, M. Fletcher and C.Southwell, 1985. The Australian kangaroopopulations, 1984. Search 16:277-9.

Grigg, G., Jarman, P. and Hume, I. (eds) 1989.“Kangaroos, Wallabies and Rat- Kangaroos”. SurreyBeatty and Sons, Sydney.

Grigg, G.C., Hale, P.T. and Lunney, D. (eds) 1995.“Conservation Through Sustainable Use of Wildlife”.Centre for Conservation Biology, University ofQueensland, Brisbane.

Grigg, G.C., Beard, L., Alexander, P., Pople A.R.and Cairns, S.C. 1999. Aerial survey of kangaroos inSouth Australia 1978-1998; a brief report focusing onmethodology. Australian Zoologist 31: 292-300.



Grigg, G.C. and Pople, A.R. 2001. Sustainable useand pest control in conservation: kangaroos as a casestudy. In “Conservation of Exploited Species” (Eds J.Reynolds, G. Mace, K. Redford and J. Robinson).Cambridge University Press, Cambridge (In press).

Hacker, R.B., McLeod, S.R. and Druhan, J.P. 2000.An exploratory analysis of the effects of kangarooharvesting on pastoral productivity in the Murray-Darling basin. Unpublished paper presented at “LivingWithin Limits: Bright Ideas”. QueenslandConservation Groups’ Annual Conference.

Lifson, N. and McClintock, R. 1996. Theory of useof the turnover rates of body water for measuringenergy and material balance. Journal of TheoreticalBiology 12:46-74.

Lunney, D. 1994a. Review of official attitudes towestern new South Wales 1901-1993 with particularreference to the fauna. In “Future of the Fauna ofWestern New South Wales” (Eds D. Lunney, S. Hand,P. Reed and D. Butcher). Pp.1-26. Royal ZoologicalSociety of New South Wales, Mosman.

Lunney, D. 1994b. Royal Commission of 1901 onthe western lands of New South Wales – anecologist’s summary. In “Future of the Fauna ofWestern New South Wales” (Eds D. Lunney, S.Hand, P. Reed and D. Butcher). Pp.221-40. RoyalZoological Society of NSW, Sydney.

Lunney, D. 1995. Kangaroo harvesting in the contextof ecologically sustainable development (ESD) andbiodiversity conservation. In “Conservation through thesustainable use of wildlife” (Eds G.C. Grigg, P.T. Hale andD. Lunney). Pp. 166-175. Centre for ConservationBiology, University of Queensland, Brisbane.

Lunney, D. and Grigg, G.C.(eds) 1988. “Kangarooharvesting and the conservation of arid lands; asymposium”. Royal Zoological Society of NSW,Mosman. Australian Zoologist 24: 121-93.

Lunney, D., Hand, S., Reed, P. and Butcher, D.(eds) 1994. “Future of the Fauna of New SouthWales”. Royal Zoological Society of NSW, Mosman.

Lunney, D. 2001. Causes of the extinction of nativemammals of the Western Division of NSW: anecological interpretation of the nineteenth centuryhistorical record. Rangeland Journal 23:44-70.

McLeod, S. 1996. The foraging behaviour of the aridzone herbivores the red kangaroo (Macropus rufus)and the sheep (Ovis aries) and its role in theircompetitive interaction, population dynamics andlife-history strategies. Ph.D Thesis, University of NewSouth Wales, Sydney.

Nagy, K.A. 1980. CO2 production in animals:analysis of potential errors in the doubly labelled watermethod. American Journal of Physiology 238:R466-73.

Nagy, K.A. 1987. Field metabolic rate and foodrequirement scaling in mammals and birds. EcologicalMonographs 57(2): 111-28.

Noble, J.C. and Tongway D.J. 1986. Herbivores inarid and semi-arid rangelands. In “Australian Soils:The Human Impact” (Eds J.S. Russel and R.F. Isbell).Pp.243-70. University of Queensland Press, Brisbane.

Norbury, G.L. and Norbury, D.C. 1993. Thedistribution of red kangaroos in relation to rangeregeneration. The Rangeland Journal 15: 3-11.

O’Dea, K. 1988. Kangaroo meat – polyunsaturatedand low in fat: ideal for cholesterol-lowering diets.Australian Zoologist 24: 140-3.

Pople, A.R. 1996. Effects of harvesting upon thedemography of red kangaroos in western Queensland.Ph.D Thesis, University of Queensland, Brisbane.

Pople, A.R. and Grigg, G.C. 1998. Commercialharvesting of kangaroos in Australia. http://www.environment.gov.au/bg/plants/wildlife/roo/roobg.htm.Document prepared for Environment Australia andpublished only on the WWW.

Rawlinson, P. 1988. Kangaroo conservation andkangaroo harvesting: intrinsic value versusinstrumental value of wildlife. In “Kangarooharvesting and the conservation of arid lands; asymposium” (Eds D. Lunney and G.C. Grigg). Pp.129-37. Royal Zoological Society of NSW, Mosman.Australian Zoologist 24(3): 121-93.

Short, J. 1985. The functional response of kangaroos,sheep and rabbits in an arid grazing system. Journal ofApplied Ecology 22: 435-47.

Short, J. 1987. Factors affecting food intake ofrangelands herbivores. In “Kangaroos: Their Ecologyand Management in the Sheep Rangelands of Australia”(Eds G. Caughley, N. Shepherd and J. Short.). Pp.84-99.Cambridge University Press, Cambridge.

Sinclair, A.J. 1988. Nutritional properties of kangaroomeat. In “Kangaroo harvesting and the conservation ofarid lands; a symposium” (Eds D. Lunney and G.C.Grigg). Pp.121-93. Royal Zoological Society of NSW,Mosman. Australian Zoologist 24: 146-8.

Sinclair, R. 1996. Mulga regeneration at Koonamore.In ‘Focus On the Future - The Heat Is On!’. (Eds L. P.Hunt and R. Sinclair.) pp. 255-6. (AustralianRangeland Society: Adelaide.)

Switala, J.P. 1995. The potential supply and value ofkangaroo meat. In “Conservation through thesustainable use of wildlife” (Eds G.C. Grigg, D. Lunneyand P.T. Hale). Pp.237-42. Centre for ConservationBiology, University of Queensland, Brisbane.

Southwell, C.J., Cairns, S.C., Palmer, R., Delaney,R. and Broers, R. 1997. Abundance of largemacropods in the eastern highlands of Australia.Wildlife Society Bulletin 25: 125-32.

Wilson, A.D. 1991. Forage utilization by sheep andkangaroos in a semi-arid woodland. The RangelandJournal 13: 81-90.

Wilson, M. 1999. “The kangaroo betrayed”. Hill ofContent Publishing, Melbourne.

Grigg


Appendix 1. Chronological list of publications by Grigg promoting the conservation benefits of controlled, sustainableharvesting of kangaroos, through better marketing, to achieve “sheep replacement therapy” for rangelands.The more significant papers are asterisked. Primary research and review papers are listed in Appendix 2, following.

Grigg, G.C. 1983. South Australian Kangaroo Manage-ment Forum – A Brief Review. Koolewong 12(3): 4-7.Grigg, G.C. 1984. Are kangaroos really under threat?Australian Natural History 21(4): 123-9.Archer, M., Flannery, T.F. and Grigg, G.C. 1985. “TheKangaroo” Chapter 5.The Kangaroo in the Future. KevinWeldon, Sydney.*Grigg, G.C. 1987. Kangaroos – a better economicbase for our marginal grazing lands? Australian Zoologist 24: 73-80.Grigg,G.C.1987. Australia’s kangaroos: their manage-ment, the public debate, and a plan for the future.Australian Wildlife Proceedings 104, Post GraduateCommittee in Veterinary Science, University ofSydney. Pp. 485-93.Grigg, G.C. 1987. Kangaroo harvesting: A newapproach. Australian Natural History 22(5): 204-5.*Grigg, G.C. 1988. Kangaroo harvesting and theconservation of the sheep rangelands. In “Kangarooharvesting and the conservation of arid and semi-aridlands; a symposium” (Eds D. Lunney and G.C. Grigg).124-28. Royal Zoological Society of NSW, Mosman.Grigg, G.C. 1988. Conservation of the sheep range-lands – are kangaroos a better economic base? AcresAustralia,The Journal of Sustainable Agriculture 1: 17-19.*Grigg, G.C. 1989. Kangaroo harvesting and theconservation of arid and semi-arid rangelands.Conservation Biology 3:194-7.*Grigg, G.C. 1991. Kangaroos, land care and animalwelfare: a proposal for change. Bulletin of the EcologicalSociety of Australia 21(2): 30-35.Grigg, G.C. 1993. Promoting the land care benefits ofharvesting kangaroos, to overcome some of the presentimpediments. In “Workshop on Kangaroo Management”(Eds G.D. Grant and B.J. Ramsay). Pp.23-6. Departmentof Primary Industries and Energy, Canberra.Grigg, G.C. 1994. Matching economic andconservation goals. In “Future of the Fauna in WesternNew South Wales” (Eds D. Lunney, S. Hand, P. Reedand D Butcher). Preface pp. iii-v. Royal ZoologicalSociety of NSW, Sydney.Pople,A.R. and Grigg, G.C. 1994. Commercial use ofwildlife for conservation. Workshop report in“Conservation Biology in Australia and Oceania” (Eds

C. Moritz and J. Kikkawa). Pp.363-6. Surrey Beatty andSons, Sydney.*Grigg, G.C. 1995. Kangaroo harvesting for conserv-ation of rangelands, kangaroos and graziers. In“Conservation through the sustainable use of wildlife”(Eds G.C. Grigg, P.T. Hale and D. Lunney). Pp.161-5.Centre for Conservation Biology, University ofQueensland, Brisbane.Grigg, G.C. and Lunney, D. 1995. Workshop report:Potential conservation benefits from kangarooharvesting. In “Conservation through the sustainableuse of wildlife” (Eds G.C. Grigg, P.T. Hale and D.Lunney). Pp.339-40. Centre for Conservation Biology,University of Queensland, Brisbane.Grigg, G.C. 1995. Prospects for a different way to lookat kangaroos: a resource not a pest. Proceedings of theAnnual Queensland Landcare Conference, Longreach1995: 52-6. (Ed B. Peterkin). Queensland Departmentof Primary Industries.Grigg, G.C. 1996. Harvesting kangaroos in Australia. In“Assessing the Sustainability of Uses of Wild Species:Case Studies and Initial Assessment Procedures” (Eds R.and C.Prescott-Allen). Pp.27-9.Occasional paper of theIUCN Species Survival Commission, Number 2. IUCN,Gland, Switzerland and Cambridge, UK.Grigg, G.C. 1996. Counting on ‘roos. (Popular accountof the aerial surveys conducted from a Drifter Ultralightaircraft.) Geo July 1996.Grigg, G.C. 1996. Opinion: Making a living from ‘roos,not sheep. Australian Geographic 45:33.Grigg, G.C. 1997. Regulated rangeland harvesting ofkangaroos – conservation and animal welfare benefits.Conference proceedings from Self-Regulation in theKangaroo Industry, September 1996.Australian WildlifeProtection Council.Grigg, G.C. 1997. Kangaroos: Sustainable use or pestcontrol? In “Sustainable Use of Wildlife: Utopiandream or unrealistic nightmare?”, pp.76-84. NatureConservation Council of NSW.*Grigg, G.C. and Pople,A.R. 2001. Sustainable use andpest control in conservation: kangaroos as a case study.In “Conservation of Exploited Species” (Eds J. Reynolds,G. Mace, K. Redford and J. Robinson). CambridgeUniversity Press, Cambridge.

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Grigg, G.C. 1979. Aeronautical aspects of aerialsurvey. In “Aerial surveys of fauna populations”.Australian National Parks and Wildlife ServiceSpecial Publication No. 1, Canberra.

Caughley, G.J., Sinclair, R.G. and Grigg, G.C. 1979.Trend of kangaroo populations in NSW Australia.Journal of Wildlife Management 43: 775-7.

Caughley, G.J., Grigg, G.C. Caughley, J.A. and Hill,G.K.E. 1980. Does dingo predation control thedensities of kangaroos and emus? Australian WildlifeResearch 7: 1-12.

Caughley, G.J., Grigg, G.C. 1981. Surveys of thedistribution and density of kangaroos in the PastoralZone of South Australia, and their bearing on thefeasibility of aerial survey in large and remote areas.Australian Wildlife Research 8: 1-11.

Caughley, G.J., Grigg, G.C. 1982. Numbers anddistribution of kangaroos in the Queenslandpastoral zone. Australian Wildlife Research 9: 365-71.

Short, J. and Grigg, G.C. 1982. The abundance ofkangaroos in suboptimal habitats wheat, intensivepastoral, mallee. Australian Wildlife Research9: 221-227.

Caughley, G.J., Short, J. and Grigg, G.C. 1983. Howmany kangaroos? Search 14: 151-2.

Caughley, G.J., Grigg, G.C. and Smith, L.A. 1985.The effect of drought on kangaroo populations.Journal of Wildlife Management 49(3): 679-685.

Grigg, G.C., Beard, L.A. Caughley, G. Grice, D.,Caughley, J.A., Shepherd, N., Fletcher, M. andSouthwell, C. 1985. The Australian kangaroopopulations, 1984. Search 16: 277-279.

Grigg, G.C. 1989. Kangaroo harvesting and theconservation of arid and semi-arid rangelands.Conservation Biology 3:194-7.

Fletcher, M, Southwell, C.J., Shepherd, N.W.,Caughley, G., Grice, D., Grigg, G.C. and Beard, J.A.1990. Kangaroo population trends in the Australianrangelands, 1980-87. Search 21:28-9.

* Grigg, G.C. Jarman, P.J. and Hume, I.D. 1990.“Kangaroos, Wallabies and Rat Kangaroos”. 835pp.Surrey Beatty and Sons, Sydney.

Calaby, J.H. and Grigg, G.C. 1989. Changes inmacropodoid communities and populations in thepast 200 years, and the future. In “Kangaroos,Wallabies and Rat Kangaroos” (Eds. G.C. Grigg,P.J. Jarman and I.D. Hume). Surrey Beatty and Sons, Sydney.

Pople, A.R., Cairns, S.C. and Grigg, G.C. 1991.Distribution and abundance of emus (Dromaiusnovaehollandiae) in relation to the environment in the South Australian Pastoral zone. Emu91: 222-229.

Cairns, S.C., Pople, A.R. and Grigg, G.C. 1991.Distribution and habitat associations of redkangaroos (Macropus rufus) and western greykangaroos (Macropus fuliginosus) in the pastoralzone of South Australia. Wildlife Research 18: 377-402.

Cairns, S.C. and Grigg G.C. 1993. Populationdynamics of red kangaroos (Macropus rufus) inrelation to rainfall in the pastoral zone of SouthAustralia. Journal of Applied Ecology 30: 444-458.

Grigg, G.C., Pople, A.R. and Beard, L,A. 1995.Movements of feral camels in central Australiadetermined by satellite telemetry. Journal of AridEnvironments 31: 459-69.

*Grigg, G.C., Hale, P.T. and Lunney, D. 1995.“Conservation through the sustainable use ofwildlife” 362pp. Centre for Conservation Biology,University of Queensland, Brisbane.

Pople,A.R., Grigg, G.C., Cairns, S.C.,Alexander, P.,Beard, L.A. and Henzell, R. 1996. Trends in thenumbers and changes in the distribution of feralgoats (Capra hircus) in the South Australian PastoralZone. Wildlife Research 23: 687-96.

Grigg, G.C., Pople, A.R and Beard, L.A. 1997.Application of an ultra-light aircraft to aerial surveysof kangaroos on grazing properties. WildlifeResearch 24: 359-372.

Pople, A.R., Cairns, S.C., Clancy, T.F., Grigg, G.C.,Beard, L.A. and Southwell, C.J. 1998. Anassessment of the accuracy of kangaroo surveysusing fixed-wing aircraft. Wildlife Research25: 315-326.

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Appendix 2: Chronological list of primary research and review publications related to the population ecology ofkangaroos in which Grigg is an author or co-author (one paper appears in both Tables). Review publications asterisked.


Pople, A.R., Cairns, S.C., Clancy, T.F., Grigg, G.C.,Beard, L.A. and Southwell, C.J. 1998. Comparisonof surveys of kangaroos in Queensland usinghelicopters and fixed-wing aircraft. RangelandJournal 20(1): 92-103.

*Pople, A.R. and Grigg, G.C. 1998. Commercialharvesting of kangaroos in Australia. http://www.environment.gov.au/bg/plants/wildlife/roo/roobg.htm. Document prepared for Environment Australiaand published only on the WWW.

McAlpine, C.A., Grigg, G.C., Mott, J.J. and Sharma,P. 1999. Influence of landscape structure onkangaroo abundance in a disturbed semi-aridwoodland in Queensland. Rangeland Journal 21(1):104-34.

Grigg, G.C., Beard, L.,Alexander, P., Pople,A.R. andCairns, S.C. 1999. Aerial survey of kangaroos inSouth Australia 1978-1998; a brief report focusingon methodology. Australian Zoologist 31: 292-300.

Grigg, G.C. and Pople, A.R. 1999. Outcomes ofthe workshop: refining aerial surveys of kangaroos.Australian Zoologist 31: (1): 317-20.

Pople, A.R., Grigg, G.C., Cairns, S.C., Beard, L.A.and Alexander, P. 2000. Trends in the numbers ofred kangaroos and emus on either side of theSouth Australian dingo fence: evidence forpredator regulation? Wildlife Research 27: 269-76.

Cairns, S.C., Grigg, G.C., Beard, L.A., Pople, A.R.and Alexander, P 2000. Western grey kangaroos(Macropus fuliginosus) in the South Australianpastoral zone: populations at the edge of theirrange. Wildlife Research 27: 309-318.

*Grigg, G.C. and Pople,A.R. 2001. Sustainable useand pest control in conservation: kangaroos as acase study. In “Conservation of Exploited Species”(Eds J. Reynolds, G. Mace, K. Redford and J.Robinson. Cambridge University Press, Cambridge.

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