Koala habitat use and population density: using field data to test the assumptions of ecological models
William Ellis A B G , Sean FitzGibbon B , Alistair Melzer A , Robbie Wilson C , Steve Johnston D , Fred Bercovitch E , David Dique F and Frank Carrick B
+ Author Affiliations
- Author Affiliations
A Koala Research Centre of Central Queensland, Central Queensland University, Rockhampton, Qld 4702, Australia.
B Koala Study Program, Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, St Lucia, Qld 4072, Australia.
C School of Biological Sciences, The University of Queensland, St Lucia, Qld 4072, Australia.
D School of Agriculture and Food Science, The University of Queensland, Gatton, Qld 4343, Australia.
E Center for International Collaboration and Advanced Studies in Primatology, Primate Research Institute & Wildlife Research Center, Kyoto University, 41-2 Kanrin Inuyama, Aichi, 484-8506, Japan.
F ERM, PO Box 1400, Spring Hill, Qld 4004, Australia.
G Corresponding author. Email: w.ellis@uq.edu.au
Australian Mammalogy 35(2) 160-165 https://doi.org/10.1071/AM12023
Submitted: 10 May 2012 Accepted: 3 December 2012 Published: 15 March 2013
Abstract
In principle, conservation planning relies on long-term data; in reality, conservation decisions are apt to be based upon limited data and short-range goals. For the koala (Phascolarctos cinereus), frequently reliance is made on the assumption that indirect signs can be used to indicate behavioural preferences, such as diet choice. We examined the relationship between the use of trees by koalas and the presence of scats beneath those trees. Tree use was associated with scat presence on 49% of occasions when koalas were radio-tracked in both central Queensland (n = 10 koalas) and south-east Queensland (n = 5 koalas), increasing to 77% of occasions when trees were rechecked the following day. Koala densities were correlated with scat abundance at sites with koala density between ~0.2 and 0.6 koalas per hectare. Our results confirm that scat searches are imprecise indicators of tree use by koalas, but demonstrate that these searches can be used, with caveats, to estimate koala population densities. We discuss how errors in estimating or applying predictive model parameters can bias estimates of occupancy and show how a failure to validate adequately the assumptions used in modelling and mapping can undermine the power of the products to direct rational conservation and management efforts.
References
Adams-Hosking, C., Grantham, H. S., Rhodes, J. R., McAlpine, C., and Moss, P. T. (2011). Modelling climate-change-induced shifts in the distribution of the koala. Wildlife Research 38, 122–130.| Modelling climate-change-induced shifts in the distribution of the koala.Crossref | GoogleScholarGoogle Scholar |
Beeton, R. (2011). Threatened Species Scientific Committee: Letter to Minister for Sustainability, Environment, Water, Population and Communities. Canberra.
Callaghan, J., McAlpine, C., Thompson, J., Mitchell, D., Bowen, M., Rhodes, J., de Jong, C., Sternberg, R., and Scott, A. (2011). Ranking and mapping koala habitat quality for conservation planning on the basis of indirect evidence of tree-species use: a case study of Noosa Shire, south-eastern Queensland. Wildlife Research 38, 89–102.
| Ranking and mapping koala habitat quality for conservation planning on the basis of indirect evidence of tree-species use: a case study of Noosa Shire, south-eastern Queensland.Crossref | GoogleScholarGoogle Scholar |
Clifton, I. D., Ellis, W. A. H., Melzer, A., and Tucker, G. (2007). Water turnover and the northern range of the koala (Phascolarctos cinereus). Australian Mammalogy 29, 85–88.
| Water turnover and the northern range of the koala (Phascolarctos cinereus).Crossref | GoogleScholarGoogle Scholar |
Commonwealth of Australia (2011). The Senate Environment and Communications References Committee report: The koala – saving our national icon.
Cristescu, R. H., Goethals, K., Banks, P. B., Carrick, F. N., and Frere, C. (2012). Experimental evaluation of koala scat persistence and detectability with implications for pellet-based fauna census. International Journal of Zoology 2012, .
| Experimental evaluation of koala scat persistence and detectability with implications for pellet-based fauna census.Crossref | GoogleScholarGoogle Scholar |
Dique, D. S., Preece, H. J., Thompson, J., and de Villiers, D. L. (2004). Determining the distribution and abundance of a regional koala population in south-east Queensland for conservation management. Wildlife Research 31, 109–117.
| Determining the distribution and abundance of a regional koala population in south-east Queensland for conservation management.Crossref | GoogleScholarGoogle Scholar |
Ellis, W., Melzer, A., Green, B., Newgrain, K., Hindell, M. A., and Carrick, F. N. (1995). Seasonal-variation in water flux, field metabolic-rate and food-consumption of free-ranging koalas (Phascolarctos cinereus). Australian Journal of Zoology 43, 59–68.
| Seasonal-variation in water flux, field metabolic-rate and food-consumption of free-ranging koalas (Phascolarctos cinereus).Crossref | GoogleScholarGoogle Scholar |
Ellis, W., Sullivan, B. J., Lisle, A. T., and Carrick, F. N. (1998). The spatial and temporal distribution of koala faecal pellets. Wildlife Research 25, 663–668.
| The spatial and temporal distribution of koala faecal pellets.Crossref | GoogleScholarGoogle Scholar |
Ellis, W., Carrick, F., Lundgren, P., Veary, A., and Cohen, B. (1999). The use of faecal cuticle examination to determine the dietary composition of koalas. Australian Zoologist 31, 127–133.
Ellis, W., Melzer, A., Carrick, F. N., and Hasegawa, M. (2002). Tree use, diet and home range of the koala (Phascolarctos cinereus) at Blair Athol, central Queensland. Wildlife Research 29, 303–311.
| Tree use, diet and home range of the koala (Phascolarctos cinereus) at Blair Athol, central Queensland.Crossref | GoogleScholarGoogle Scholar |
Ellis, W., Melzer, A., and Bercovitch, F. B. (2009). Spatiotemporal dynamics of habitat use by koalas: the checkerboard model. Behavioral Ecology and Sociobiology 63, 1181–1188.
| Spatiotemporal dynamics of habitat use by koalas: the checkerboard model.Crossref | GoogleScholarGoogle Scholar |
Ellis, W., Melzer, A., Clifton, I. D., and Carrick, F. (2010). Climate change and the koala Phascolarctos cinereus: water and energy. Australian Zoologist 35, 369–377.
| Climate change and the koala Phascolarctos cinereus: water and energy.Crossref | GoogleScholarGoogle Scholar |
Hasegawa, M. (1995). Habitat utilisation by koalas (Phascolarctos cinereus) at Point Halloran, Queensland. M.Sc. Thesis, University of Queensland, Brisbane.
Karanth, K. U., Gopalaswamy, A. M., Kumar, N. S., Vaidyanathan, S., Nichols, J. D., and MacKenzie, D. I. (2011). Monitoring carnivore populations at the landscape scale: occupancy modelling of tigers from sign surveys. Journal of Applied Ecology 48, 1048–1056.
| Monitoring carnivore populations at the landscape scale: occupancy modelling of tigers from sign surveys.Crossref | GoogleScholarGoogle Scholar |
Kendall, K. C., Metzgar, L. H., Patterson, D. A., and Steele, B. M. (1992). Power of sign surveys to monitor population trends. Ecological Applications 2, 422–430.
| Power of sign surveys to monitor population trends.Crossref | GoogleScholarGoogle Scholar |
Latham, J., Staines, W., and Gorman, M. (1996). The relative densities of red (Cervus elaphus) and roe (Capreolus capreolus) deer and their relationship in Scottish plantation forests. Journal of Zoology 240, 285–299.
| The relative densities of red (Cervus elaphus) and roe (Capreolus capreolus) deer and their relationship in Scottish plantation forests.Crossref | GoogleScholarGoogle Scholar |
Lunney, D., O’Neill, L., Matthews, A., and Sherwin, W. B. (2002). Modelling mammalian extinction and forecasting recovery: koalas at Iluka (NSW, Australia). Biological Conservation 106, 101–113.
| Modelling mammalian extinction and forecasting recovery: koalas at Iluka (NSW, Australia).Crossref | GoogleScholarGoogle Scholar |
Lunney, D., Crowther, M. S., Shannon, I., and Bryant, J. V. (2009). Combining a map-based public survey with an estimation of site occupancy to determine the recent and changing distribution of the koala in New South Wales. Wildlife Research 36, 262–273.
| Combining a map-based public survey with an estimation of site occupancy to determine the recent and changing distribution of the koala in New South Wales.Crossref | GoogleScholarGoogle Scholar |
MacKenzie, D. I. (2006). Modeling the probability of resource use: the effect of, and dealing with, detecting a species imperfectly. Journal of Wildlife Management 70, 367–374.
| Modeling the probability of resource use: the effect of, and dealing with, detecting a species imperfectly.Crossref | GoogleScholarGoogle Scholar |
Martin, R., Handasyde, K., and Krockenburger, A. (2008). Koala Phascolarctos cinereus. In ‘The Mammals of Australia’. (Eds S. van Dyck and R. Strahan.) pp. 198–201. (New Holland: Sydney.)
Matthews, A., Lunney, D., Gresser, S., and Maitz, W. (2007). Tree use by koalas (Phascolarctos cinereus) after fire in remnant coastal forest. Wildlife Research 34, 84–93.
| Tree use by koalas (Phascolarctos cinereus) after fire in remnant coastal forest.Crossref | GoogleScholarGoogle Scholar |
McAlpine, C. A., Rhodes, J. R., Bowen, M. E., Lunney, D., Callaghan, J. G., Mitchell, D. L., and Possingham, H. P. (2006a). The importance of forest area and configuration relative to local habitat factors for conserving forest mammals: a case study of koalas in Queensland, Australia. Biological Conservation 132, 153–165.
| The importance of forest area and configuration relative to local habitat factors for conserving forest mammals: a case study of koalas in Queensland, Australia.Crossref | GoogleScholarGoogle Scholar |
McAlpine, C. A., Bowen, M. E., Callaghan, J. G., Lunney, D., Rhodes, J. R., Mitchell, D. L., Pullar, D., and Possingham, H. P. (2006b). Testing alternative models for the conservation of koalas in fragmented rural–urban landscapes. Austral Ecology 31, 529–544.
| Testing alternative models for the conservation of koalas in fragmented rural–urban landscapes.Crossref | GoogleScholarGoogle Scholar |
McAlpine, C., Rhodes, J., Peterson, A., Possingham, H., Callaghan, J., Curran, T., Mitchell, D., and Lunney, D. (2007). Planning guidelines for koala conservation and recovery. A guide to best planning practice. Australian Koala Foundation and The University of Queensland, Brisbane. Also available at: http://espace.library.uq.edu.au/view/UQ:124088
McAlpine, C., Rhodes, J., Bowen, M., Lunney, D., Callaghan, J., Mitchell, D., and Possingham, H. (2008). Can multiscale models of species’ distribution be generalized from region to region? A case study of the koala. Journal of Applied Ecology 45, 558–567.
| Can multiscale models of species’ distribution be generalized from region to region? A case study of the koala.Crossref | GoogleScholarGoogle Scholar |
Melzer, A., Baudry, C., Kadiri, M., and Ellis, W. (2011). Tree use, feeding activity and diet of koalas on St Bees Island, Queensland. Australian Zoologist 35, 870–875.
| Tree use, feeding activity and diet of koalas on St Bees Island, Queensland.Crossref | GoogleScholarGoogle Scholar |
Mitchell, P. (1990). The home ranges and social activity of koalas – a quantitative analysis. In ‘Biology of the Koala’. (Eds A. K. Lee, K. A. Handasyde and G. D. Sanson.) pp. 171–187. (Surrey Beatty: Sydney.)
Moore, B. D., and Foley, W. J. (2005). Tree use by koalas in a chemically complex landscape. Nature 435, 488–490.
| Tree use by koalas in a chemically complex landscape.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXksVeisrk%3D&md5=63530ccd72e30212e23504a0ef9e623fCAS |
Moore, B. D., Lawler, I. R., Wallis, I. R., Beale, C. M., and Foley, W. J. (2010). Palatability mapping: a koala’s eye view of spatial variation in habitat quality. Ecology 91, 3165–3176.
| Palatability mapping: a koala’s eye view of spatial variation in habitat quality.Crossref | GoogleScholarGoogle Scholar |
Nagy, K. A., and Martin, R. (1985). Field metabolic rate, water flux, food consumption and time budget of koalas, Phascolarctos cinereus (Marsupialia: Phascolarctidae) in Victoria. Australian Journal of Zoology 33, 655–665.
| Field metabolic rate, water flux, food consumption and time budget of koalas, Phascolarctos cinereus (Marsupialia: Phascolarctidae) in Victoria.Crossref | GoogleScholarGoogle Scholar |
Patterson, B. R., and Murray, D. L. (2008). Flawed population viability analysis can result in misleading population assessment: a case study for wolves in Algonquin park, Canada. Biological Conservation 141, 669–680.
| Flawed population viability analysis can result in misleading population assessment: a case study for wolves in Algonquin park, Canada.Crossref | GoogleScholarGoogle Scholar |
Phillips, S., and Callaghan, J. (1995). The spot assessment technique for determining the significance of habitat utilisation by koalas. In ‘Conference on the Status of the Koala in 1995’. (Australian Koala Foundation: Brisbane.)
Phillips, S., and Callaghan, J. (2000). Tree species preferences of koalas (Phascolarctos cinereus) in the Campbelltown area south-west of Sydney, New South Wales. Wildlife Research 27, 509–516.
| Tree species preferences of koalas (Phascolarctos cinereus) in the Campbelltown area south-west of Sydney, New South Wales.Crossref | GoogleScholarGoogle Scholar |
Phillips, S., and Callaghan, J. (2011). The Spot Assessment Technique: a tool for determining localised levels of habitat use by koalas Phascolarctos cinereus. Australian Zoologist 35, 774–780.
| The Spot Assessment Technique: a tool for determining localised levels of habitat use by koalas Phascolarctos cinereus.Crossref | GoogleScholarGoogle Scholar |
Pilkey, O. H., and Pilkey-Jarvis, L. (2007). ‘Useless Arithmetic: Why Environmental Scientists Can’t Predict the Future.’ (Columbia University Press: New York.)
Preece, H. (2007). Monitoring and modelling threats to koala populations in rapidly urbanising landscapes: Koala Coast, south east Queensland, Australia. Ph.D. Thesis, The University of Queensland, Brisbane.
Reed, P., and Lunney, D. (1990). Habitat loss: the key problem for the long-term survival of koalas in New South Wales. In ‘Koala Summit: Managing Koalas in New South Wales’. (Eds D. Lunney, C. A. Urquhart and P. Reed.) pp. 9–31. (NSW National Parks and Wildlife Service: Hurstville.)
Rhodes, J. R., Callaghan, J. G., McAlpine, C. A., de Jong, C., Bowen, M. E., Mitchell, D. L., Lunney, D., and Possingham, H. P. (2008). Regional variation in habitat-occupancy thresholds: a warning for conservation planning. Journal of Applied Ecology 45, 549–557.
| Regional variation in habitat-occupancy thresholds: a warning for conservation planning.Crossref | GoogleScholarGoogle Scholar |
Rhodes, J., Lunney, D., Moon, C., Matthews, A., and McAlpine, C. (2011). The consequences of using indirect signs that decay to determine species’ occupancy. Ecography 34, 141–150.
| The consequences of using indirect signs that decay to determine species’ occupancy.Crossref | GoogleScholarGoogle Scholar |
Rykiel, E. J. (1996). Testing ecological models: the meaning of validation. Ecological Modelling 90, 229–244.
| Testing ecological models: the meaning of validation.Crossref | GoogleScholarGoogle Scholar |
Schmolke, A., Thorbek, P., DeAngelis, D. L., and Grimm, V. (2010). Ecological models supporting environmental decision making: a strategy for the future. Trends in Ecology & Evolution 25, 479–486.
| Ecological models supporting environmental decision making: a strategy for the future.Crossref | GoogleScholarGoogle Scholar |
Seabrook, L., McAlpine, C., Baxter, G., Rhodes, J., Bradley, A., and Lunney, D. (2011). Drought-driven change in wildlife distribution and numbers: a case study of koalas in south west Queensland. Wildlife Research 38, 509–524.
| Drought-driven change in wildlife distribution and numbers: a case study of koalas in south west Queensland.Crossref | GoogleScholarGoogle Scholar |
Smith, P., and Smith, J. (1990). Decline of the urban koala (Phascolarctos cinereus) population in Warringah Shire, Sydney. Australian Zoologist 52, 109–129.
Sullivan, B. J., Baxter, G. S., and Lisle, A. T. (2002). Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. I. Faecal pellet sampling protocol. Wildlife Research 29, 455–462.
| Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. I. Faecal pellet sampling protocol.Crossref | GoogleScholarGoogle Scholar |
Sullivan, B. J., Baxter, G. S., Lisle, A. T., Pahl, L., and Norris, W. M. (2004). Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. IV. Abundance and conservation status. Wildlife Research 31, 19–29.
| Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. IV. Abundance and conservation status.Crossref | GoogleScholarGoogle Scholar |
Wilson, G. J., and Delahay, R. J. (2001). A review of methods to estimate the abundance of terrestrial carnivores using field signs and observation. Wildlife Research 28, 151–164.
| A review of methods to estimate the abundance of terrestrial carnivores using field signs and observation.Crossref | GoogleScholarGoogle Scholar |
Woosnam-Merchez, O., Cristescu, R., Dique, D., Ellis, W., Beeton, R., Simmonds, J., and Carrick, F. (2012). What faecal pellet surveys can and cannot reveal about the ecology of koalas (Phascolarctos cinereus). Australian Zoologist 36, 192–200.
