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Marvellous macropods

marvellous-macropods-cVladislavJirousek-dreamstime

Excerpt from a forthcoming book by Maria Taylor on Australia’s uneasy and deadly history since settlement with its native wildlife. Can we replace disrespect and removal with understanding and appreciation?

CAPTION ABOVE:  Family of Red Kangaroo, Macropus rufus, on pasture. © Vladislav Jirousek, Dreamstime.

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Celebrating resilience, athleticism and efficiency … and ecosystem services

“The Kangaroo is a most marvellous and unique animal.  It has been falsely maligned by tradition, with profiteers now retaining the status quo by all means available to them.  The majority of Australians are being duped by environmental pirates.  This has been achieved by manipulating our inherent nature … with the use of half-truths, lies and gross exaggerations.”

— David Nicolls, former shooter. Australian Wildlife Protection Council
book Kangaroos Myths and Realities, p33.

*  *  *  *  *  *  *  *  *

“Big Red suddenly shot away to the left. He lengthened his leaps, leant further forward, and drew away from the dogs … in the direction in which the kangaroo was going, there was a thick clump of trees. The country was rough, broken gullies, uneven surface, gibbers and rocks. Big Red led straight for that … he lengthened his leaps for long approaches; he shortened them for twisty turns; he put into practical use the many hours he had spent at aimless dancing and playing with his mates in the mob.” 

— Henry G Lamond, Big Red.

*  *  *  *  *  *  *  *  *

 “Native herbivores maintain environments beneficial to other species and keep ecosystems functioning when other rarer or endangered grassland/woodland animals drop out.” 

— Dan Ramp, Centre for Compassionate Conservation,
University of Technology, Sydney.

*  *  *  *  *  *  *  *  *

THE OTHER DAY I was again stopped in my tracks as I observed an adult Grey Kangaroo effortlessly clearing a 4ft (1.2m) fence in my neighbourhood. Nearby wildlife rescuer Dr Rosemary Austen told me that a large male apparently cleared a 6.6 foot (2m) fence at Possumwood, their animal recovery centre. The approach might be side-on, not unlike a human competitive high-jumper.

Zoologist and macropod specialist David Croft — who has straddled the divide between academic and advocate — thinks we would do well to emulate the kangaroo and call ourselves ‘a kangaroo’ with pride in this country.

He wrote: “if we did we would be celebrating diversity, the successful occupation of most of Australia’s terrestrial ecosystems, resilience to our climatic extremes, athleticism, careful conservation of energy and water needs, and individualism in a rich social life.” He also encourages us to learn from the Aboriginal peoples that we are part of the land and with the kangaroo, re-establish our relationship to it. (Croft, Myths and Realities, 2005, p31) 

It remains for newer Australians to get over post-colonial ideas vis-a-vis wildlife, kangaroos and wallabies in particular: that the only relationship involves commercial ‘harvesting’, eradicating competition for vegetation on private property or caring for the injured as an outcome of human activity.

For European-thinking humans, to do this would seem to require a shift to more cooperation and sharing, to accept the land and its unique features — not so much domination, improvement and exploitation. Some have learned that.

Land management tips from indigenous animals

Zoologist Hugh Tyndale-Biscoe relates in a 2005 paper his experience in the 1960s at Woorandara station in western NSW where the owner did not shoot kangaroos but instead learned from them how to graze sustainably in that environment. Owner Keith Turner “used the kangaroos as an indicator of the health of his pastures: when the kangaroos left a particular paddock he knew it was time to shift the sheep and spell it.

“As a result, his property had large old man saltbushes and much native pasture every year. On a succession of visits through the dry and wet years of 1963–72 we witnessed the change of abundance of kangaroos, but also saw that Keith had lambing ewes when the neighbouring properties were de-stocking sheep.

“By following the responses of the indigenous animals, Keith was able to live sustainably on the property that had been in his family for three generations.” (Hugh Tyndale-Biscoe, Kangaroos and Sheep: The Unequal Contest,  Australasian Science; Jul 2005; 26, 6; ProQuest Science Journals p29.)

There is little direct ecological research of how kangaroos interact with their environment because the research focus has always been ‘pest or resource’. Published observations like the above are rare appreciation of what kangaroos can teach us. But there is a fair bit of physiological research underscoring what an amazing athlete the kangaroo is. Some clues also exist on macropod co-evolution with the grassland and woodland ecologies of Australia.

Meet the macropods

Antilopine Walleroo-Greg Schechter-Flickr CC BY 2zeroSix large kangaroo species and seven species of wallaby are closely related and share the genus name Macropus derived from ancient Greek for ‘long foot’. That includes the Red kangaroo, the two species of Greys and the Euro or Wallaroo that are the target of the commercial hunt. (The Antilopine kangaroo and the Bernard’s Wallaroo in the northern tropics are not commercially hunted).

IMAGE RIGHT: Antilopine Walleroo.
By Greg Schechter. Flickr CC BY 2.0

The outstanding evolutionary success of Macropus in a changeable and often harsh environment over millions of years has been attributed to three traits: they ferment grass in the foregut before the contents are released for further digestion and thus hold food for longer and recycle components of metabolism; they hop, and they have an economical pattern of reproduction. (Ref ibid Tyndale-Biscoe, Kangaroos and sheep: the unequal contest, Australasian Science, July 2005, 26,6 p29.)

While a similar foregut digestion pattern characterises sheep, cattle and camels, kangaroos are able to utilise much poorer vegetation with low nitrogen content and Euros can survive without drinking water because of their unique metabolic processes. Kangaroos also have a lower metabolic rate than same-sized introduced mammals meaning their energy requirements are less (Ibid).

Kangaroos know when to stop eating, plus energy efficiency

native-herbivores-cCarol-Lynn-District-Bulletin-Oct2016
IMAGE: Carol Lynn, District Bulletin, Oct 2016.

There is an oft-misunderstood comparison between sheep and kangaroos and their impact on grazing land. Research has shown kangaroos use less feed to maintain energy individually and in aggregate than the same number of wool sheep, let alone meat sheep or goats.

In addition, under normal wild circumstances, sheep and kangaroos may prefer different plants and, as we’ve seen, kangaroos know when to move on to protect their resource. These adaptive features have led some to the unrealistic dream of saving Australia’s ravaged grazing landscapes by farming kangaroos instead of sheep or cattle or having farmers ‘own’ the wildlife like soil or plants for harvesting at will.

The distinctive athleticism, speed and energy efficiency shown by the large kangaroos is on display with movement across the countryside — movement that has awed those who appreciate the unique, from tourists to advertising agencies.

The unique art of hopping

The advantage of hopping as a means of locomotion was discovered by Australian biologists Terence Dawson and Richard Taylor in 1973. Dawson has studied kangaroos for 50 years through the University of NSW and its Arid Zone Research Station at Fowler’s Gap, where David Croft also did much of his research work. Dawson poured this knowledge into the seminal book Kangaroos which tells the reader most of what they might want to know about kangaroo physiology, social relations and unique adaptive features to the Australian environment.

Here I learned that the earliest ancestors of kangaroos are likely to have branched off from a small tree-dwelling possum-like marsupial sometime after 55 million years ago when the known fossil record for marsupials starts. How and when hopping evolved is still uncertain but the advantages are better described. Hopping, writes Dawson, is an extension of the gallop to achieve higher speeds, and one might imagine a highly energetic possum doing this on the ground to avoid predators. (Kangaroos, Terence J Dawson, Second edition 2014, CSIRO Publishing, Collingwood, Vic., p8.)

Kangaroos attain optimal energy-use at higher speeds. At 22 km/hour hopping was providing substantial benefits using about 25% less energy than that measured for a dog running at that speed. At 40 km/hour the gap could widen further to 50% energy-use compared to a four-footed mammal. “This energy efficiency, together with structural specialisations, allows kangaroos to go even faster. If given time to get moving they can out-speed quadrupedal predators such as Dingos”. (Ibid p11)

In a country where the weather has long been boom and bust, economy of movement allows mobs to travel rapidly for relatively large distances like 25km to the next ephemeral rainfall and better food. This is particularly an adaptive advantage for arid range species including the Red Kangaroo, but it is also a reason they have been demonised as descending in ‘plague proportions’.

“Kangaroos are really special mammals. Work over the past half century has turned the notion that they belong to an inefficient, primitive group of mammals totally on its head,” says Dawson. Together with American and Canadian co-scientists, he identified another handy adaptive feature: the use by the kangaroos of their tail as a “fifth leg” for forward momentum while grazing, which they do much of the time.

As with much previous work, this discovery also relied on study of the heavily persecuted and ‘harvested’ Red Kangaroo — the largest of the remaining kangaroo species. Published in 2014, the finding was that when grazing, these large macropods move both hind feet forward as a pair while the tail was more than a resting point. It released movement energy just like a leg would. The researchers established that the muscles in the tail as well as in the hind legs are highly aerobic, with a lot of mitochondria — the power houses in cells that provide energy.

Environmental role of native grazers 

If you go looking for, as I have, studies on the ecological roles of native grazers, you will come up short because there is hardly any literature. This lack underlines the wildlife management focus and funding aimed at studies for commercial interests, particularly for the pastoral industry since colonial times.

Information on ecology and biodiversity values can be found here and there as parts of larger analyses. For instance the collated information in the report that engulfed the Canberra Environment and Sustainability Resource Centre and Robin Tennant-Wood in government censure back in 2009.

The report mildly questioned the ACT’s goal of killing nature reserve kangaroos by noting that kangaroos provide ecosystem services. That report noted they keep the grass mowed in fire-prone landscapes and assist in faster regeneration of native grasslands following fire or drought.

Also noted  was that human intervention (with culling) disrupts the normal stable breeding cycle — possibly encouraging more breeding attempts, and may also create voids attracting others into the space. All this was not welcome news to a government with a culling program to justify.

The report’s perspective was supported by ecologist and macropod specialist Dan Ramp then of the University of NSW; and co-founder the Centre for Compassionate Conservation at the University of Technology Sydney. He said a very basic thing about ecology — that a healthy ecosystem function is linked with the species that evolved with it.

His words challenged the latest narrative for demonising kangaroos, that these native grazers are somehow separate from the rest of grassland biodiversity and a threat to same. This idea has been publicly aired by some applied ecologists, as we’ve seen, to justify lethal management. In the ACT it further allows park management to evade the welfare code nominally protecting mothers and joeys simply by citing environmental goals.

Ramp highlighted the importance of remaining native herbivores (common kangaroos, wallabies, wombats), as “key species” in grassland ecosystems. They have a role in maintaining environments beneficial to other species and, mostly overlooked, in keeping ecosystems functioning when other rarer or endangered grassland/woodland animals drop out.

Common species fill the gap as others move to extinction

“Native herbivores such as kangaroos and wombats, play a vital role in ecosystem functioning but are often victimized and treated with lack of concern because of socio-political factors and historical value judgements rather than heeding biological and ecological information,” he noted, adding:

“Common species can play key roles in conferring short-term resistance to reductions in ecosystem functions, as rare and uncommon species are lost from the system. We now have entered Earth’s sixth mass-extinction event, this time human driven. The setting aside of protected areas may not be sufficient to prevent loss of biodiversity.”

(Canberra Environment and Sustainability Resource Centre, 2009. The Role of Biodiversity in Climate Change Adaptation — a report to the ACT Commissioner for the Environment. Also Ramp D, Coulson G, 2002. Density Dependence in foraging habitat preference of Eastern Grey Kangaroos, Oikos 98, 393–402.)

Kangaroos for example can be regenerators of native grasses in a number of ways. They bury seed into holes made by their toenails. Their long tails brush soil over seeds. As nutrient recyclers, their urine and faeces are well-matched natural fertilisers. Their role in grassland regeneration with seed dispersal after drought and fire evolved with the continental ecosystems.

Unlike introduced livestock, kangaroos do not disturb or pull up root systems and therefore grasslands regenerate quickly. Soft-footed kangaroos also don’t compact the soil or cause erosion both of which damage native plant ecosystems.

The Environment Centre report countered a prevailing government narrative of unnatural kangaroo fecundity and population increases supposedly happening just in Canberra. It referred readers to a seminal 2000 study at Yan Yean reserve in Victoria. That study, in a confined area with access to historical data, took place in a temperate grassland ecosystem with Eastern Grey Kangaroos minus natural predators or road-kill possibility. It reported the kangaroo population reached equilibrium and stayed stably self-regulating over a 50-year period. (Coulson G, Alviano P, Ramp D, Way S, McLean N, Yazgin V, 2000, The kangaroos of Yan Yean  etc in book Nature Conservation in Production Environment, pp146–156; also earlier paper 1999.)

Anecdotal stories I shared earlier from Canberra suburban householders told how they lived with neighbourhood mobs for 20–30 years; called them friends; and observed stable numbers overall — until recently when the government came to cull them.

Just across the border, ecosystem benefits applauded

In July 2013 I reported on a biodiversity situation in the Queanbeyan Nature Reserve bordering Canberra. In the national capital regular kangaroo culling was occurring aided by a shifting public relations argument by this time that kangaroos were somehow a threat to various endangered species including the Grassland Earless Dragon.

In the Queanbeyan Reserve, where no culling took place, three of Australia’s most endangered species were recovering or maintaining their populations following a drought that hit the area five years earlier. The Earless Dragon population count had dropped from 50 to nil during the drought. But by 2013 the little lizards were recolonising the reserve. The other two endangered species there were the Golden Sun Moth and the daisy-like Button Wrinklewort.

The NSW government ecologist based in Queanbeyan said that habitat conditions, dryness for example, were the operative influences on the presence of these species.

The scientific view here was that sympathetic grazing by unregulated native grazers or modest stock numbers was a natural sequence keeping the country open with varied grass heights. In turn, these created shelter for other species. The patchwork pattern retained soil moisture and encouraged insects, food for the dragon for example.

Grassland grazed by kangaroos in natural densities retained tall tussocks, which disappeared with heavy stock grazing. In similar fashion, a 2012 national recovery plan for the Button Wrinklewort lauded kangaroo grazing for keeping the landscape open for this native plant. Domestic stock will eat this plant but kangaroos don’t. The moths were also doing well in a grazed, diverse plant community.

Weeds, according to the ecologist and the recovery plans, are far more of a threat to endangered grassland species than native grazers. Other threats are habitat fragmentation, agricultural practices, urban expansion, changed fire regimes and predation by domestic and feral animals. (Maria Taylor, Survival in Queanbeyan, a good news story, July 2013, The District Bulletin.)

Kangaroos populate around water, a common myth

Contrary to popular opinion, kangaroo species are not as bound to water sources as domestic stock. Their water needs and consumption are much lower. In the absence of baseline studies the evidence is anecdotal and assumed comparing what once was with what is now.

In the marginal grazing lands of the interior, the traditional home of the Red Kangaroo, it is possible that populations have increased with the addition of new bore water points for grazing operations where there was never water before. At the same time, more animals arrived as kangaroo populations were pushed further inland due to human activity on more fertile land.

The argument that kangaroo populations have exploded everywhere since white settlement and European improvements is much less likely in the more fertile lands east and just west of the Great Divide.

Kangaroo home ranges are not primarily focused on water sources. Kangaroo species prefer areas that offer shelter near some food source (Dawson ibid, p156).  In the fertile landscape this habitat is now scarce with the land cleared for stock and cropping, a cycle that recently ramped up again.

Recall the accounts of early settlers/surveyors, that the land was ideal for native grazers being well-watered and open under Aboriginal land management. Europeans in the longer term did not improve food or water sources beyond a short term flush of grass after clearing. Dams were established but natural water courses were being silted up. Meanwhile, settlement eradication of wildlife plus recreational hunting and bounties created unnatural densities of native grazers where they could still survive habitat loss and shooting.

It is part of the demonization narrative that grazier ‘improvements’ have driven population increases compared to pre-colonial times. In regard to water, of course native animals would avail themselves of the numerous stock water points installed by graziers if needed, particularly in drought and in increasing heat with climate change conditions.

On the other hand, turning off stock watering points once established in the landscape and particularly in drought, has been indicted as an unnecessary cruelty to all wildlife in the area including birds, reptiles and other species.

 

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One thought on “Marvellous macropods

  1. Thank you Maria for the detailed research and writing you have done on the beauty of the kangaroo,and its justifiable place in the environment and in the hearts of thinking Australians. Your book should be compulsory reading for all politicians.

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