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  • Cited by 15
  • Print publication year: 2003
  • Online publication date: June 2012

6 - Survey and census methods: population distribution and density

Summary

INTRODUCTION

A population study of a wild primate typically involves a considerable investment of time and resources (i.e. money, equipment, labour) and it is vital to ensure that such effort is well targeted. When designing your study, a key issue is whether your study objectives genuinely demand an absolute estimate of the population density from either a census (a total count) or a survey (in which density is estimated from statistically valid samples), or whether less information will suffice. Relative estimates of density using data from methods such as ‘catch-per-unit effort’ from trapping or systematic searching do not provide absolute densities but, as long as the sampling methods and other conditions are standardised, can allow reliable comparisons between locations and monitoring of population change over time. Population indices are based on indirect indicators, such as the density of faeces or other characteristic signs, that can be correlated with population density. Such methods may be a more practical alternative to searching for secretive, hard-to-find animals.

In practice, no population survey or census is completely bias free and many studies may find that a reliable relative population estimate or index is more achievable than a reliable absolute estimate of the population size (Bibby et al., 1992; Greenwood, 1996; Krebs, 1999). There is a trade-off between the depth of the data gathered and the number of replicate samples that can be obtained.

References
Anderson, D. R., Laake, J. L., Crain, B. R. & Burnham, K. P. (1979). Guidelines for line transect sampling of biological populations. J. Wildlife Manag. 34, 141–6
Anderson, D. R., Burnham, K. P. & Crain, B. R. (1985). Estimating population size and density using line transect sampling. Biom. J. 7, 723–31
Begon, M. (1979). Investigating Animal Abundance, Capture–Recapture for Biologists. London: Edward Arnold
Bibby, C. J. & Buckland, S. T. (1987). Bias of bird census results due to detectability varying with habitat. Acta Ecol. 8, 103–12
Bibby, C. J., Burgess, N. D. & Hill, D. A. (1992). Bird Census Techniques. London: Academic Press
Blom, A., Almasi, A., Heitkonig, I. M. A., Kpanou, J. B. & Prins, H. H. T. (2001). A survey of the apes in the Dzanga-Ndoki National Park, Central African Republic: a comparison between the census and survey methods of estimating the gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes) nest group density. Afr. J. Ecol. 39, 98–105
Bollinger, E. K., Gavin, T. A. & McIntyre, D. C. (1988). Comparison of transects and circular-plots for estimating bobolink densities. J. Wildlife Manag 52, 777–86
Brockelman, W. Y. & Ali, R. (1987). Methods of surveying and sampling forest primate populations. In Primate Conservation in the Tropical Rain Forest ed. C. W. Marsh & R. A. Mittermeier, pp. 23–62. New York: Alan, R. Liss
Buckland, S. T., Anderson, D. R., Burnham, K. P. & Laake, J. L. (1993). Distance Sampling: Estimating Abundance of Biological Populations. London: Chapman & Hall
Buckland, S. T., Goudie, I. B. J. & Borchers, D. L. (2000). Wildlife population assessment: past developments and future directions. Biometrics 56, 1–12
Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L. & Thomas, L (2001). Introduction to Distance Sampling: Estimating Abundance of Biological Populations. Oxford: Oxford University Press
Charles-Dominique, P. (1972). Écologie et vie sociale de Galago demidovii (Fischer 1808, Prosimii). Z. TierpsycholSuppl. 9, 7–41
Charles-Dominique, P. (1977). Ecology and Behaviour of Nocturnal Primates. London: Duckworth
Edwards, A. & White, L. (2000). Maps, compasses, GPS units and principles of navigation. In Conservation Research in African Rain Forests: A Technical Handbook, ed. L. White & A. Edwards, pp. 31–51. New York: Wildlife Conservation Society
Fashing, P. J. & Cords, M. (2000). Diurnal primate densities and biomass in the Kakamega Forest: an evaluation of census methods and a comparison with other forests. Am. J. Primatol. 50, 139–52
Fossey, D. (1974). Observation on the home range of one group of mountain gorillas. Gorilla gorilla beringei. Anim. Behav 22, 568–81
Fossey, D. & Harcourt, A. H. (1977). Feeding ecology of free-ranging mountain gorillas (Gorilla gorilla beringei). In Feeding Ecology, ed. T. H. Clutton-Brock, pp. 415–47. London: Academic Press
Furuichi, T., Hashimoto, C. & Tashiro, Y. (2001). Extended application of a marked-nest census method to examine seasonal changes in habitat use by chimpanzees. Int. J. Primatol 22, 913–28
Garner, D. L., Underwood, H. B. & Porter, W. F. (1995). Use of modern infrared thermography for wildlife population surveys. Environ. Manag. 19, 233–8
Gill, R. M. A., Thomas, M. L. & Stocker, D. (1997). The use of portable thermal imaging for estimating deer population density in forest habitats. J. Appl. Ecol. 34, 1273–86
Greenwood, J. J. D. (1996). Basic techniques. In Ecological Census Techniques: A Handbook, ed. W. J. Sutherland, pp. 11–110. Cambridge: Cambridge University Press
Harcourt, A. H., Fossey, D. & Sabater Pi, J. (1981). Demography of Gorilla gorilla. J. Zool. Lond. 195, 215–33
Harcourt, A. H., Kineman, J. & Campbell, G. (1983). Conservation of the Virunga gorilla population. Afr. J. Ecol. 21, 139–42
Hashimoto, C. (1995). Population census of the chimpanzees in the Kalinzu Forest, Uganda: comparison between methods with nest counts. Primates 36, 477–88
Havens, K. J. & E. J. Sharp. (1998). Using thermal imagery in the aerial survey of animals. Wildlife Soc. Bull. 26, 17–23
Hubbs, A. H., Karels, T. & Boonstra, R. (2000). Indices of population size for burrowing mammals. J. Wildlife Manag. 64, 296–301
Krebs, C. J. (1999). Ecological Methodology, 2nd edition. Menlo Park, CA: Addison Wesley Longman
McGraw, W. S. (1998). Three monkeys nearing extinction in the forest reserves of eastern Côte d'Ivoire. Oryx 32, 233–6
McNeilage, A., Plumtre, A. J., Brock–Doyle, A. & Vedder, A. (2001). Bwindi Impenetrable National Park, Uganda: Gorilla census, 1997. Oryx 35, 39–47
Nichols, J. D. & M. J. Conroy (1996). Techniques for estimating abundance and species richness. In Measuring and Monitoring Biological Diversity: Standard Methods for Mammals, ed. D. E. Wilson, F. R. Cole, J. D. Nichols, R. Rudran &. M. S. Foster, pp. 177–234. Washington, DC: Smithsonian Institution Press
Parnell, R. J. (2000). Information from animal tracks and trails. In Conservation Research in African Rain Forests: A Technical Handbook, ed. L. White & A. Edwards, pp. 157–89. New York: Wildlife Conservation Society
Payne, J. (1987). Surveying orang-utan populations by counting nests from a helicopter: a pilot survey in Sabah. Primate Cons. 8, 92–103
Schaller, G. B. (1963). The Mountain Gorilla: Ecology and Behavior. Chicago: University of Chicago Press
Sholley, C. R. (1991). Conserving gorillas in the midst of guerillas. In American Association of Zoological Parks and Aquariums, Annual Conference Proceedings, pp. 30–7
Singh, M., Lindburg, D. G., Udhayan, A., Kumar, M. A. & Kumara, H. N. (1999). Status survey of slender loris Loris tardigradus lydekkerianus in Dindigul, Tamil Nadu, India. Oryx 33, 31–7
Southwood, T. R. E. & Henderson, P. A. (2000). Ecological Methods, 3rd edition. Oxford: Blackwell Science
Thomas, L., Laake, J. L., Derry, J. F., Buckland, S. T., Borchers, D. L., Anderson, D. R., Burnham, K. P., Strindberg, S., Hedley, S. L., Marques, F. F. C., Pollard, J. H. & Fewster, R. M. (1998). Distance 3.5. Research Unit for Wildlife Population Assessment. St Andrews. University of St Andrews
Tutin, C. E. G. & Fernandez, M. (1984). Nationwide census of gorilla (Gorilla g. gorilla) and chimpanzee (Pan t. troglodytes) populations in Gabon. Am. J. Primatol. 6, 313–36
Tutin, C. E. G., Parnell, R. J., White, L. J. T. & Fernandez, M. (1995). Nest building by lowland gorillas in Lope Reserve, Gabon: environmental influences and implications for censusing. Int. J. Primatol 16, 53–76
Krunkelsven, E., Inogwabini, B.-I. & Draulans, D. (2000). A survey of bonobos and other large mammals in Salonga National Park, Democratic Republic of Congo. Oryx 34, 180–8
Wemmer, C., Kunz, T. H., Lundie–Jenkins, G. & McShea, W. J. (1996). Mammalian signs. In Measuring and Monitoring Biological Diversity: Standard Methods for Mammals, ed. D. E. Wilson, F. R. Cole, J. D. Nichols, R. Rudran &. M. S. Foster, pp. 157–76. Washington, DC: Smithsonian Institution Press
White, L. & Edwards, A. (2000). Methods for assessing the status of animal populations. In Conservation Research in African Rain Forests: A Technical Handbook, ed. L. White & A. Edwards, pp. 225–73. New York: Wildlife Conservation Society