Pooling local expert opinions for estimating mammal densities in tropical rainforests.

C.A. van der Hoeven, W.F. de Boer, H.H.T. Prins

Research output: Contribution to journalArticleAcademicpeer-review

36 Citations (Scopus)


Methods currently used for assessing wildlife density in rainforests are time and money consuming. The precision of the most commonly used methods is disputed, but accepted because more exact methods are not available. In this study a new method of wildlife density estimation is explained. The new method is less time and money consuming, but yields comparable results with classical methods. The method was tested in the field in Cameroon and compared with transect surveys in the area and with relevant literature. The Pooled Local Expert Opinion (PLEO) method is based on the knowledge of local experts. A number of hunters were asked to estimate wildlife abundance in a specified area, after which the density/km2 was calculated for 33 wildlife species. These estimates were pooled and extrapolated for the whole study area. Elephant (Loxodonta africana) density outside the National Park was estimated to be 0.06 animals/km2, and 0.3 inside. Buffalo (Syncerus caffer) density for the study area was estimated at 0.2 animals/km2 and gorilla (Gorilla gorilla) density at 1.05 per km2. Transect surveys carried out at the same time for considerably more money, taking far more time, produced too few data to calculate densities. The evaluation of the PLEO method was favourable and the method offers a substitute for conventional methods of estimating wildlife density in rainforests. The methodology is simple and it can be incorporated in many tropical biodiversity and conservation projects. It can also be used for long-term monitoring of wildlife status in a given area. In contrast with classical methods, the PLEO method is low in cost and assures local ownership of the results.
Original languageEnglish
Pages (from-to)193-204
JournalJournal for Nature Conservation
Issue number4
Publication statusPublished - 2004


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