Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR07066
RESEARCH ARTICLE
Contents Vol 35(4)

Frequency and precision of aerial surveys for kangaroo management

A. R. Pople
+ Author Affiliations
- Author Affiliations

The Ecology Centre, School of Integrative Biology, University of Queensland, Brisbane, Qld 4072, Australia. Present address: Invasive Plants and Animals, Biosecurity Queensland, Department of Primary Industries and Fisheries, GPO Box 46, Brisbane, Qld 4001, Australia. Email: tony.pople@dpi.qld.gov.au

Wildlife Research 35(4) 340-348 https://doi.org/10.1071/WR07066
Submitted: 8 June 2007  Accepted: 24 December 2007   Published: 27 June 2008

Abstract

The appropriate frequency and precision for surveys of wildlife populations represent a trade-off between survey cost and the risk of making suboptimal management decisions because of poor survey data. The commercial harvest of kangaroos is primarily regulated through annual quotas set as proportions of absolute estimates of population size. Stochastic models were used to explore the effects of varying precision, survey frequency and harvest rate on the risk of quasiextinction for an arid-zone and a more mesic-zone kangaroo population. Quasiextinction probability increases in a sigmoidal fashion as survey frequency is reduced. The risk is greater in more arid regions and is highly sensitive to harvest rate. An appropriate management regime involves regular surveys in the major harvest areas where harvest rate can be set close to the maximum sustained yield. Outside these areas, survey frequency can be reduced in relatively mesic areas and reduced in arid regions when combined with lowered harvest rates. Relative to other factors, quasiextinction risk is only affected by survey precision (standard error/mean × 100) when it is >50%, partly reflecting the safety of the strategy of harvesting a proportion of a population estimate.


Acknowledgements

This project was supported by an ARC SPIRT grant to Hugh Possingham, Gordon Grigg and Stuart Phinn at the University of Queensland, with financial contributions from Queensland, New South Wales, South Australian and Commonwealth conservation agencies and Packer Tanning. The manuscript was improved by comments from two anonymous referees.


References

Anderson D. R., and Burnham K. P. (1976). Population ecology of the mallard. VI. The effect of exploitation on survival. U.S. Fish and Wildlife Service Resource Publication No. 128.

Andrew, N. L. , and Mapstone, B. D. (1987). Sampling and the description of spatial pattern in marine ecology. Oceanography and Marine Biology: An Annual Review 25, 39–90.
Bayliss P. (1987). Kangaroo dynamics. In ‘Kangaroos: their Ecology and Management in the Sheep Rangelands of Australia’. (Eds G. Caughley, N. Shepherd and J. Short.) pp. 119–134. (Cambridge University Press: Cambridge.)

Burgman M. A., Ferson S., and Akcakaya H. R. (1993). ‘Risk Assessment in Conservation Biology.’ (Chapman and Hall: London.)

Burnham, K. P. , White, G. C. , and Anderson, D. R. (1984). Estimating the effect of hunting on annual survival rates of adult mallards. Journal of Wildlife Management 48, 350–361.
| Crossref | GoogleScholarGoogle Scholar | Caughley G. (1977). ‘Analysis of Vertebrate Populations.’ (Wiley and Sons: London.)

Caughley G. J. (1979). Design for aerial censuses. In ‘Aerial Survey of Fauna Populations’. pp. 15–23. (Australian Government Publishing Service: Canberra.)

Caughley G. (1987). Ecological relationships. In ‘Kangaroos: their Ecology and Management in the Sheep Rangelands of Australia’. (Eds G. Caughley, N. Shepherd and J. Short.) pp. 159–187. (Cambridge University Press: Cambridge.)

Caughley, G. , Grigg, G. C. , and Smith, L. (1985). The effect of drought on kangaroo populations. Journal of Wildlife Management 49, 679–685.
| Crossref | GoogleScholarGoogle Scholar | Crawley M. J. (1983). ‘Herbivory.’ (Blackwell Scientific Publications: London.)

Davis, S. A. , Pech, R. P. , and Catchpole, E. A. (2002). Populations in variable environments: the effect of variability in a species’ primary resource. Philosophical Transactions of the Royal Society of London series B 357, 1249–1257.
| Crossref | GoogleScholarGoogle Scholar | PubMed | Fowler C. W. (1987). review of density dependence in populations of large mammals. In ‘Current Mammalogy’. (Ed. H. H. Genoways.) pp. 401–441. (Plenum Press: New York.)

Gerrodette, T. (1987). A power analysis for detecting trends. Ecology 68, 1364–1372.
| Crossref | GoogleScholarGoogle Scholar | Grigg G. (2002). Conservation benefit from harvesting kangaroos: status report at the start of a new millenium. In ‘A Zoological Revolution. Using Native Fauna to Assist in its Own Survival’. (Eds D. Lunney and C. Dickman.) pp. 53–76. (Royal Zoological Society of New South Wales & Australian Museum: Sydney.)

Hacker R. B., McLeod S. R., and Druhan J. (2003). Final Report for Project #D8003. Evaluating Alternative Management Strategies for Kangaroos in the Murray Darling Basin. NSW Department of Agriculture, Dubbo.

Harris, R. B. (1986). Reliability of trend lines obtained from variable counts. Journal of Wildlife Management 50, 165–171.
| Crossref | GoogleScholarGoogle Scholar | McLeod S., and Pople T. (1998). Optimal exploitation strategies for kangaroo populations in variable environments. In ‘Proceedings of the 11th Australian Veterbrate Pest Conference, 3–8 May 1998, Bunbury, Western Australia’. pp. 375–380.

Milner-Gulland, E. J. , Shea, K. , Possingham, H. , Coulson, T. , and Wilcox, C. (2001). Competing harvesting strategies in a simulated population under uncertainty. Animal Conservation 4, 157–167.
| Crossref | GoogleScholarGoogle Scholar | Pople A. R. (1996). Effects of harvesting upon the demography of red kangaroos in western Queensland. Ph.D. Thesis, The University of Queensland, Brisbane.

Pople A. (2003). Harvest management of kangaroos during drought. Unpublished report to New South Wales National Parks and Wildlife Service, Dubbo, NSW. http://www.nationalparks.nsw.gov.au/PDFs/NSWNPWS_drought_harvestmanagement_colour.pdf

Pople A. R. (2006). Modelling the spatial and temporal dynamics of kangaroo populations for harvest management. Final report to the Department of Environment and Heritage, Canberra.

Pople A. R., and Grigg G. C. (1998). Commercial harvesting of kangaroos in Australia. Environment Australia, Canberra. http://www.ea.gov.au/biodiversity/trade-use/wild-harvest/kangaroo/harvesting/index.html

Robertson, G. G. (1986). The mortality of kangaroos in drought. Australian Wildlife Research 13, 349–354.
| Crossref | GoogleScholarGoogle Scholar | Robertson G. (1987). Plant dynamics. In ‘Kangaroos: their Ecology and Management in the Sheep Rangelands of Australia’. (Eds G. Caughley, N. Shepherd and J. Short.) pp. 50–68. (Cambridge University Press: Cambridge.)

Williams B. K., Conroy M. J., and Nichols J. D. (2002). ‘Analysis and Management of Animal Populations: Modeling, Estimation, and Decision Making.’ (Academic Press: San Diego, CA.)