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Review of eastern grey kangaroo counts and derivation of sustainable density estimates in the Australian Capital Territory


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Key conclusions and recommendations


  1. The logic and evidence underpinning the KMP is valid but the conservation culling components of the plan are properly adaptive and will be refined as the results of current research and monitoring reduce uncertainty about key parameters such as target densities.

  2. Unmanaged kangaroo populations reduce the biomass of ground-layer vegetation which has adverse impacts on some other native species. Therefore culling kangaroos is a valid management action. The current management ensures sustained populations of kangaroos at densities that purport to allow more vegetation and more secure populations of threatened native species.

  3. There is published evidence that the current target density of kangaroos (set by modelling at 1 per hectare) does benefit other native plants and animals but managers recognise there are gaps in understanding the details of how temperate grassland ecosystems work as components of it (mostly kangaroo numbers) are manipulated. Current projects conducted by ACT staff and PhD studies underway at ANU should fill some of these knowledge gaps.

  4. One key question is whether the density of 1 kangaroo per hectare is the ‘correct’ target for all times, all nature reserves and under all environmental and biological conditions. We suspect it will be too high (100 large herbivores per km2 is still a very high density relative to other systems and species, and certainly constitutes no threat to the sustainability of the kangaroos). The results of an ACT project currently being conducted will will help identify whether the average density set is the best or at least within the optimal range of densities.

  5. Each nature reserve is a sort of habitat island with a variety of assets and threats, with varying degrees of connection between the reserves. The KMP might be supported with a set of individual site plans, with kangaroo management as but one action within each plan. Site-specific monitoring will allow management to be fine-tuned.

  6. ACT managers have two options to lead to this site-based approach. They can nominate a number of nature reserves to be managed to allow the rare native species to be maintained with resilient populations and achieve it as efficiently as possible (cost minimisation). Or they can set a fixed annual budget and determine how many nature reserves can be effectively managed within the budget (benefit maximisation).

  7. The methods being used to count kangaroos and estimate densities are sound, but we recommend the following four changes. (i) direct and sweep counts need more replication, (ii) uncertainties in components of direct, sweep and pellet count methods should be addressed in analyses, (iii) a team of trained professionals (i.e. staff and/or contractors) should be the core for all counts, although we acknowledge the wider social and public relations benefits of including volunteers, and (iv) the counts should be conducted as close as possible to the intended cull. Further, consideration should be given to conducting a second post-cull count perhaps six months later, at least in a subset of reserves.

  8. Sweep counts have several potentially significant problems, including traffic problems if kangaroos flee the counters. We recommend ACT consider either replacing this method with direct or walked-line transects, or if this is not possible to use core trained staff as above.

  9. It would be valuable to conduct a trial to compare the costs, accuracy, and precision of the four counting methods across different habitat types and kangaroo densities.

  10. The methods used to conduct kangaroo counts should be described in standard operating manuals that can be updated as required. This would ensure continuity for a program that will have to be sustained long after current staff have left.

  11. Publication of research by ACT staff and others should be facilitated because this work is potentially of high standard and of interest to a wider audience, as well as providing ACT decision-makers and other stakeholders with the confidence of peer review.

Acknowledgements


We thank the ACT Territory and Municipal Services Directorate for support during our visit to Canberra.

References


ACT 2010. ACT kangaroo management plan. Conservation series, Territory and Municipal Services, ACT, Canberra, 182 pp.

Anon. undated. Project plan: Kangaroos and conservation – researching the relationships between kangaroo density, herbage mass, pasture floristics and reptile diversity in grassy ecosystems around Canberra. Environment and Sustainable Development, ACT Government, Canberra, unpubl report.

Barton PS, Manning AD, Gibb H, Wood JT, Lindenmayer DB, Cunningham SA 2011. Experimental reduction of native vertebrate grazing and addition of logs benefit beetle diversity at multiple scales. Journal of Applied Ecology 48: 943–951.

Bayliss P 1987. Kangaroo dynamics. Pp. 119–133. In: Caughley G, Shepherd N, Short J (Eds.). Kangaroos their ecology and management in the sheep rangelands of Australia. Cambridge University Press, Cambridge.

Bayne P, Harden B, Pines K, Taylor U 2000. Controlling feral goats by shooting from a helicopter with and without the assiatance of ground-based spotters. Wildlife Research 27: 517–523.

Buckland ST, Anderson DR, Burnham KP, Laake JL, Borchers DL, Thomas L 2001. Introduction to distance sampling: Estimating abundance of biological populations. Oxford University Press, New York.

Buckland ST, Anderson DR, Burnham KP, Laake JL, Borchers DL,Thomas L 2004. Advanced distance sampling: Estimating abundance of biological populations. Oxford University Press, New York.

Caughley G, Shepherd N, Short J 1987. Kangaroos their ecology and management in the sheep rangelands of Australia. Cambridge University Press, Cambridge, 253 pp.

Caughley G 1987. Ecological relationships. Pp. 159–187. In: Caughley G, Shepherd N, Short J (Eds.). Kangaroos their ecology and management in the sheep rangelands of Australia. Cambridge University Press, Cambridge.

Choquenot D, Parkes J 2001. Setting thresholds for pest control: how does pest density affect resource viability? Biological Conservation 99: 29–46.

Clancy TF, Pople AR, Gibson LA 1997. Comparison of helicopter line transects with walked line transects for estimating densities of kangaroos. Wildlife Research 24: 397–409.

Coulson GM, Raines JA 1985. Methods for small-scale surveys of grey kangaroos. Wildlife Research 12: 119–125.

Dimond WJ, Osborne WS, Evans MC, Gruber B, Sarre SD 2012. Back to the brink: population decline on the endangered grassland earless dragon (Tympanocryptis pinguicolla) following its rediscovery. Herpetological Conservation and Biology 7: 132–149.

Environment & Sustainable Development 2013. Kangaroo population estimates in summer 2013 and recommendations for conservation culling. Unpublished ACT Parks Report. 31 p.

Fletcher D 2006. Population dynamics of eastern grey kangaroos in temperate grasslands. PhD Thesis, University of Canberra.

Fletcher D 2007. Managing eastern grey kangaroos Macropus giganteus in the Australian Capital Territory: reducing overabundance – of opinion. Pp. 117–128. In: Lunney D, Eby P, Hutchings P, Burgin S (Eds.). Pest or guest: the zoology of overabundance. Royal Society of New South Wales, Mosman, NSW.

Fletcher D 2013. Kangaroo population estimates in late 2013 and recommendations for conservation culling. Unpublished ACT Parks report. 51 p.

Glass R 2013. Assessing the precision and accuracy of distance sampling for estimating the abundance of eastern grey kangaroos. M.Sc. Thesis, Department of Zoology, University of Melbourne.

Howland B 2008. Pellet count techniques for estimating the abundance of eastern grey kangaroos in the A.C.T. B.Sc.(Hons) Thesis, Fenner School of Environment and Society, Australian National University.

Jarman PJ, Phillips CM 1989. Diets in a community of macropod species. Pp. 143 149. In: Kangaroos, wallabies and rat-kangaroos. Grigg G, Jarman P, Hume I (Eds.). Surrey Beatty.

Johnson, C.N.; Jarman, P. J. 1987. Macropod Studies at Wallaby Creek: VI. A validation of the use of dung-pellet counts for measuring absolute densities of populations of Macropodids. Australian Wildlife Research 14: 139–145.

Johnson, C.N.; Jarman, P.J.; Southwell, C. J. 1987. Macropod Studies at Wallaby Creek. 5. Patterns of defecation by eastern gray kangaroos and red-necked wallabies. Australian Wildlife Research 14: 133–138.

le Mar, K., Southwell, C. and McArthur, C. 2001. Evaluation of line-transect sampling to estimate nocturnal densities of macropods in open and closed habitats. Wildlife Research 28: 9–16.

McIlroy JC, Saillard RJ 1989. The effect of hunting with dogs on the numbers and movements of feral pigs, Sus scrofa, and the subsequent success of poisoning exercises in Namadgi National Park, A.C.T. Australian Wildlife Research 16: 353–363.

McIntyre S 2005. Biodiversity attributes of different sward structures in grazed grassland. Ecological Management and Restoration 6: 71–73.

McIntyre S, Stol J, Harvey J, Nicholls AO, Campbell M, Reid A, Manning AD, Lindenmayer D 2010. Biomass and floristic pattrerns in the ground layer vegetation of box-gumgrassy eucalypt woodland in Goorooyaroo and Mulligans Flat Nature Reserves, Australian Capital Territory. Cunninghamia 11: 319–357.

Manning AD, Cunningham RB, Lindenmayer DB 2013. Bringing forward the benefits of coarse woody debris in ecosystem recovery under different levels of grazing and vegetation density. Biological Conservation 157: 204–214.

Marques FFC, Buckland ST, Goffin D, Dixon CE, Borchers DL, Mayle BA, Peace AJ 2001. Estimating deer abundance from line transect surveys of dung: sika deer in southern Scotland. Journal of Applied Ecology 38: 349–363.

MarquesTA, Buckland ST, Bispo R, Howland B 2013. Accounting for animal density gradients using independent information in distance sampling surveys. Statistical Methods & Applications DOI 10.1007/s10260-012-0223-2

Mayle BA, Peace AJ, Gill RMA 1999. How many deer? A field guide to estimating deer population size. Forestry Commission, Edinburgh. 96 p.

Neave HM, Tanton MT 1989. The effects of grazing by kangaroos and rabbits on the vegetation and the habitat of other fauna in the Tidbinbilla Nature Reserve, Australian Capital Territory. Australian Wildlife Research 16: 337–351.

Ninti One 2013. Managing the impacts of feral camels across remote Ausytralia. Final report of the Australian feral camel management project. McGregor M, Hart Q, Davies R (Eds.). Australian Government.

Ratcliffe PR 1987. Red deer population changes and the independent assessment of population size. Symposium Zoological Society London 58: 153–165.

Robertson G 1987. Plant dynamics. Pp. 50–68. In: Caughley G, Shepherd N, Short J (Eds.). Kangaroos their ecology and management in the sheep rangelands of Australia. Cambridge University Press, Cambridge.

Robertson P, Evans M 2010. National recovery plan for the grassland earless dragon Typanocryptis pinguicolla. ACT Department of Territory and Municipal Services, Canberra, 58 p.

Saunders G, Kay B 1991. Movements of feral pigs (Sus scrofa) at Sunny Corner, New South Wales. Wildlife Research 18: 49–61.

Sinclair ARE, Fryxell JM, Caughley G 2006. Wildlife ecology, conservation, and management. 2nd edition, Blackwell Publishing, 469 p.

Southwell C 1994. Evaluation of walked transect counts for estimating macropod density. Journal of Wildlife Management 58: 348–356.

Southwell C 1989. Techniques for monitoring the abundance of kangaroo and wallaby populations. Pp. 659–693. In: Grigg G, Jarman P, Hume I (Eds.). Kangaroos, wallabies and rat-kangaroos, Surrey Beatty.

Thomas L, Buckland ST, Rexstad EA, Laake JL, Strindberg S, Hedley SL, Bishop JRB, Marques TA, Burnham KP 2010. Distance software: design and analysis of distance sampling surveys for estimating population size. Journal of Applied Ecology 47: 5–14.

Thomas L, Laake JL, Rexstad EA, Strindberg S, Marques FFC, Buckland ST, Borchers DL, Anderson DR, Burnham KP, Burt ML, Hedley SL, Pollard JH, Bishop JRB, Marques TA 2009. DISTANCE 6.0. Release 2. - Research Unit for Wildlife Population Assessment, University of St. Andrews, UK. Available at: http://www.ruwpa.st-and.ac.uk/distance/

Thompson WL, White GC, Gowan C 1998. Monitoring Vertebrate Populations. - Academic Press, San Diego, California, USA, 365 pp.

Todd CR, Forsyth DM, Choquenot D 2008. Modelling the effects of fertility control on koala-forest dynamics. Journal of Applied Ecology 45: 568–578.

Williams BK, Nichols JD, Conroy M.J 2002. Analysis and Management of Animal Populations. Academic Press: USA.





1 Eastern grey kangaroos diet is mostly grass (Jarman & Phillips 1989)

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