Estimating the herpetofaunal species richness of Pangkor Island, Peninsular Malaysia

Herpetological surveys of Southeast Asian tropical ecosystems rarely, if ever, result in complete inventories. This is due to the fact that surveying to completion requires huge investments in terms of search effort. As a result, the presented species lists usually represent subsets of the total herpetofaunal assemblage and consequently do not shed light on the total species richness of the investigated area. This is regrettable as species richness is an elementary measure of biodiversity that underlies many ecological models and conservation strategies. By recording not just species but species per unit of search effort, an extended dataset results which can be used to generate estimates of total species richness. In this study, the herpetofauna of Pangkor Island, Peninsular Malaysia is used as an example. In 2009 and 2010, the first herpetological surveys were carried out on this small, 18 km2, island. Those surveys recorded 43 species of reptiles and 13 species of amphibians. In this study, total reptile species richness was estimated by fitting several models to the sample-based rarefaction curve as well as by application of the nonparametric Chao-I estimator. Of the applied models, the 4-parameter Weibull function was shown to be superior, a finding that is in line with several other studies. Consequently, the use of this model is recommended. On the basis of the fitted 4-parameter Weibull-function, 69 reptile species are expected to occur on Pangkor Island. As for amphibians, total species richness was estimated to be 17. As such, a remarkably extensive herpetofaunal assemblage inhabits this small island.