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Can livestock grazing benefit biodiversity?

Grazing by livestock (mainly sheep and cattle) has irreversibly degraded many natural ecosystems in Australia. Consequently, stock are usually removed from public land when new conservation reserves are…

There are sound ecological reasons for introducing grazing animals to some wild areas, but this shouldn’t act as a cover for non-scientific grazing. Richard Lehnert

Grazing by livestock (mainly sheep and cattle) has irreversibly degraded many natural ecosystems in Australia. Consequently, stock are usually removed from public land when new conservation reserves are declared. The damaging effects of livestock on ecosystems such as rivers, wetlands and the alps are well known.

On the other hand, ecologists have recommended that stock continue to graze in certain types of reserves. For over a decade, some National Parks in western NSW and northern Victoria have been grazed by sheep to create habitat for the endangered bird, the Plains Wanderer. In Tasmania, a number of threatened native plant species survive in grazed areas; if stock are removed the plants are smothered by thick grasses and decline. Elsewhere, short-duration (or “crash”) grazing has been recommended to control exotic (weedy) grasses and promote native plants.

In each case, grazing hasn’t been adopted because of a political compromise between production and conservation goals. Instead, it has been supported by conservation biologists to achieve specific ecological outcomes. The same ecologists have often opposed grazing in other regions (especially the alps) where grazing does not deliver desired outcomes.

How can livestock grazing benefit biodiversity conservation in these places, but not others? In each case, managed grazing creates an open habitat that is suitable for plants and animals that cannot persist beneath tall, thick grass. This mechanism is only relevant in a small number of Australian ecosystems – particularly lowland grasslands and grassy woodlands on productive soils in areas of moderate to high rainfall.

Grazing is not required to maintain diversity in all grassy ecosystems, and is rarely needed in dry, infertile sites where low fertility constrains grass growth. Indeed, a recent Victorian study found that grazing by stock and kangaroos promoted the diversity of native plants in fertile, well-watered sites, but reduced diversity in dry, unproductive areas.

If grazing is to be used for conservation purposes, a number of circumstances need to be met. Stock must preferentially eat the dominant grasses rather than other native plant species. Stock must also be controlled so they graze areas needing treatment and not other areas. In addition, being heavy, hard-footed animals, they should be excluded from wet areas where they can “pug-up” the soil. These points sound simple, but are difficult and expensive to administer in large reserves that contain many vegetation types and few internal fences.

For example, in a recent study, my colleagues and I examined how grazing affected an area containing a mosaic of wetlands dominated by native plants and grasslands dominated by exotic (weedy) plants. Unfortunately, grazing did not control the exotic plants as stock preferred to graze the lush native wetlands rather than the less palatable weedy grassland. A better outcome may have occurred if stock were restricted to the weedy grasslands. However, the cost of erecting fences around each habitat is considerable, and fences would detract from the reserve’s scenic and recreational values.

Another challenge is to develop flexible but rigorous approaches so that stock can be quickly introduced and removed as ecosystem conditions change. This is difficult in Australia’s variable climate. Usually, few (if any) stock are needed in dry periods, but large mobs are needed to control grass growth after heavy rains. Adjusting stocking levels to rapidly changing habitat conditions will always be a challenge for conservation managers and graziers.

What do we need to do before we consider using grazing for conservation purposes? First, the local problem and goals need to be clearly described (for example, “reduce cover of dominant grasses from 70% to 20%”). Infrastructure (fencing and water points) must be adequate to confine stock to targeted problem areas. Trigger points (say, levels of grass cover) must be specified to indicate when livestock are to be introduced and removed. Grazing effects must be properly monitored, including treatment and control areas. Finally, costs and benefits need to be compared against alternative treatments such as burning.

Livestock grazing has the potential to provide a useful management tool to achieve conservation objectives in some ecosystems at some times. However, the political rationale for grazing must be driven by sound ecological objectives, to ensure that “conservation grazing” is not used as an argument to extract production gains at the environment’s expense.

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19 Comments sorted by

  1. Tim Scanlon

    Debunker

    Nicely put. As you say, this really is a situation needs case. Grazing to control certain grasses and plants can stop weed infestation, but the benefits will depend greatly on the native species, the invasive species and the animals. Given how selective animals are in their grazing habits, in what they eat, how they eat it, and how this changes given differing densities, the application of grazing isn't as simple as yes or no.

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    1. Pat OBrien

      Activist

      In reply to Tim Scanlon

      So what's wrong with using kangaroos to graze these areas instead of livestock? The ACT government shoots hundreds of kangaroos each year, and then has to put sheep and cattle into some of those areas to reduce the fire risk.

      Sometimes they even mow some of these grassy areas, that the kangaroos would have kept short, if they hadn't shot them.

      If there wasn't a commercial kangaroo Industry that has heavily reduced kangaroo numbers in many areas of NSW there would be no need to introduce livestock. Kangaroos have been controlling and dispersing native plants for thousands of years. Why cant they still do it?

      Answer; Because there's not enough of them left, so we run cattle and sheep to do what the kangas used to do.
      How smart are we humans?

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    2. Tim Scanlon

      Debunker

      In reply to Tim Scanlon

      Pat, I'm afraid you are using specious reasoning. And I never said that kangaroos couldn't be part of that grazing control, hence my use of the term "animals", but to use kangaroos requires area and grazing control to avoid erosion.

      You are associating kangaroos with grazing, weed control and culling, whilst ignoring the timelines associated and the grazing habits of animals. You are also assuming continuous grazing, which I'd have to say should be rarely used, if ever.

      You ask two rhetorical…

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    3. Pat OBrien

      Activist

      In reply to Tim Scanlon

      Tim, I don't necessarily disagree with you, except on a couple of matters.

      There are plenty of introduced cattle fodder plants that kangaroos eat, which is why farmers hate them so much. Kangaroo populations have crashed in all commercial shooting zones in both NSW and WA, Government data shows this.

      It's only the banning of kangaroo imports to Russia that has allowed numbers in these shooting areas to slowly build up. And of course kangaroos don't cause erosion. And its not just "licensed…

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    4. Bernie Masters

      environmental consultant at FIA Technology Pty Ltd, B K Masters and Associates

      In reply to Tim Scanlon

      Pat, can you please point me in the direction of the WA govt data you refer to? I live in south west WA and we are experiencing the highest kangaroo numbers recorded in my 36 years living down here. Local conservation and landcare groups have given up relying on shooters to reduce roo numbers and are now fencing off large areas of bushland to totally exclude kangaroos so that the understorey vegetation has a chance to regenerate. The RACWA reports that they are paying out on record numbers of crashes with roos so I'm really keen to see where you have got the data from to show that roo numbers have crashed in WA.

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    5. Tim Scanlon

      Debunker

      In reply to Tim Scanlon

      Thanks for clarifying Pat, I see what you are getting at now.

      I agree that kangaroos could be researched better and ideally there could be some way of incorporating them into vegetation management. Even sheep and cattle, which we have bred for millennia to be efficient grazers and converters, are not fully understood in terms of grazing habits. The advantage of these examples is that we do understand density management and consumption changes, such as selection pressure. Ideally we'd know this…

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    6. Tim Scanlon

      Debunker

      In reply to Tim Scanlon

      @Bernie I haven't seen any solid numbers for WA either, but I have heard anecdotally that kangaroo numbers are rising and starting to cause significant crop damage. It is hard to say if this is from migration from the pastoral areas or an increase in numbers here or just simply observer bias.

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    7. Pat OBrien

      Activist

      In reply to Tim Scanlon

      Hi Bernie, I didn't say WA, I said NSW and SA. WA is a different kettle of fish because they don't export much kangaroo meat, but I'm pleased to hear kanga populations are increasing. When I was there a few years ago, they were pretty low.

      If you look at the Fed. Environment webpage, its very difficult to find any hard data on kangaroo populations, quotas etc, because they want it to be that way.

      I'm not an academic, so don't have access to Uni library resources, but if we can find data with our limited resources, so can others with better access, I presume.

      You may want to Google "wildlife protection" or "kangaroo protection" to get any accurate data. I must say that WA overshot their quota by thousands of kangaroos a few years back, I don't know if the management is any better now....I doubt it.

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  2. Wil B

    B.Sc, GDipAppSci, MEnvSc, Environmental Planner

    The only issue is that everything that you have written above is "boring sciency stuff" that doesn't fit into easy narratives of the National Party and their boosters in the Weakly Times and the Hun, such as last week.

    Cows good! Greenies BAD! That's the sort of logic they use.

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  3. Bernie Masters

    environmental consultant at FIA Technology Pty Ltd, B K Masters and Associates

    controlled grazing by livestock is now a reasonably common and recommended management action in certain parts of of south west WA. Along the edges of the Ramsar-listed Vasse Wonnerup estuaries, grazing of fenced off riparian areas in spring reduces introduced grass cover. In many dryland revegetation areas, stock are introduced for a few hours or days to control undesirable exotics and assist native plant regeneration.
    Overall, as Ian has pointed out, grazing is not a one size fits all management tool and it needs careful and science-based application to be effective.

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  4. Bernie Masters

    environmental consultant at FIA Technology Pty Ltd, B K Masters and Associates

    Pat, good point about using kangaroos instead of stock but the use of native grazing animals is much more difficult to control and manage in some areas, especially where roo numbers are extremely high as in coastal south west WA where I live. Kangaroo grazing is also listed as a threatening process under the federal EPBC Act which shows that some native plants are preferentially eaten by them, so roos can't be a solution in all situations, just as introduced stock can't be a solution in all situations.

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  5. Helen King

    PhD researcher and tutor at Australian National University

    great article, thanks. As you say, 'controlled' grazing is the key. It's difficult in many circumstances but with technology like solar powered electric fencing may not be impossible. An aspect you didn't cover is that a controlled graze of desirable plants to stimulate biomass production give them a competitive advantage, something we want to avoid with the undesirable ones.

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  6. Neville Mattick

    Grazier: ALP Member at A 4th Generation Grazing Station

    From my experience controlled grazing is an intense business, just as weed control is.

    On Public land I am largely opposed to it, excluding exceptional circumstances where it can be proven as a benefit in the short term.

    Perhaps land that has been neglected (here I mean a lot in private hands) could benefit from controlled grazing to the point where the owner resumes responsibility for Invasive Weeds present.

    Land should not be transacted (sold) until a 'Fitness for Sale' statement is…

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  7. Gerard Wedderburn-Bisshop

    logged in via email @worldpreservationfoundation.org

    An interesting article - looking for the positives! A pity most of Australia's beef production occurs on northern rangelands and savanna where controlled grazing is prohibitive due to water point spacing and fence costs. The first sentence in this article sums up the fate of these pastures.

    I am reminded of a term coined by a long-time Queensland pasture agronomist and climate scientist Greg McKeon: the "hydro-illogical cycle", which is:

    - it rains, grass grows, graziers stock up
    - drought comes, graziers hold on to stock due to lower prices
    - drought continues, most pastures are flogged, devoid of edible grass
    - government steps in with drought aid and permits to cut down trees that stock will eat such as mulga
    - rain comes, washes away all the (unprotected) soil
    - cycle continues

    It's good to look for positives, but the first sentence sums it up.

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  8. Angus Whyte

    logged in via Twitter

    Thanks for starting the discussion, this is a very interesting topic as I know grazing has degraded much of our landscape, I also know that resting that area will just continue the degradation in all but rain forest environments. One of the points I would like to make is "grazing is not grazing", there are so many variables grazing is a tool and depending on whose hands it is in it can destroy or rehabilitate. With landscape management you don't want the stock to eat the weeds, most of the time…

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    1. Pat OBrien

      Activist

      In reply to Angus Whyte

      One of the unknowns in managing grazing for biodiversity in the future, as some commentators have mentioned, is Climate Change. While no-one appears to know exactly what will happen, my thoughts are that in the next 20/30/50 years, much of Australia's grazing landscapes may be unusable for grazing, or any other sort of farming.

      That particlularly applies to the huge, largely multinational owned properties. It may also be that the semi-arid zones may never be able to utilised for agriculture…

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  9. mark gardner

    just a humble person

    Hi all

    This is a most excellent conversation to have! There is no doubt that uncontrolled grazing has led to an ecological simplification in the landscape, and ultimately degradation. Its easy to focus on the animals.

    However, if you can look beyond the animals, its actually the "management of the animals" that is where the opportunity for change lies....

    If the grazing pattern moves from "uncontrolled" to "controlled".... that is.... the time in which the plants and animals are together…

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  10. Leigh T

    Hobby Farmer

    Very interesting and thanks, Ian, for illuminating us.

    I've just finished reading "Temperate Woodland Conservation and Management" (2010) edited by David Lindemayer, Andrew Bennett and Richard Hobs. This book has over 40 chapters with different authors and it cites several hundred peer reviewed articles and very clearly represents state of the art knowledge. Many of the authors and cited papers set out the arguments for culling a range of native animals including the more common macropods, Brush…

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