ORIGINAL PAPER Herbarium records do not predict rediscovery of presumed nationally extinct species Kwek Yan Chong • Serena M. L. Lee • Aik Teck Gwee • Paul K. F. Leong • Samsuri Ahmad • Wee Foong Ang • Alvin F. S. L. Lok • Chow Khoon Yeo • Richard T. Corlett • Hugh T. W. Tan Received: 2 January 2012 / Accepted: 14 June 2012 / Published online: 28 June 2012 Ó Springer Science+Business Media B.V. 2012 Abstract Rediscoveries of species previously thought to be extinct present a dilemma to conservation biology. On one hand, such instances offer the chance to change the course of events away from one that would have led to extinctions. On the other hand, public support for conservation may wane if scientists are frequently seen to overstate and prematurely declare extinctions. Recent studies have adopted a probabilistic approach to infer extinc- tion, using sightings or collections and statistical models to calculate the chance that a species may still be extant. We conduct the first broad-scale test of such models using a recently compiled national red list and national herbarium collection records, including collections of presumed nationally extinct species made after the red list publication, which constitute ‘‘rediscoveries’’. There was little evidence that the probabilities calculated by these models were associated with rediscoveries over a 3.5-year period. Current proba- bilistic models of extinction using sighting records could hence be inadequate for use with most natural history collection data. Keywords Extinct species  Rediscovery  Lazarus effect  Herbarium collections  Sighting rate equations Preliminary results were presented at the 15th Biological Sciences Graduate Congress at the University of Malaya. Electronic supplementary material The online version of this article (doi:10.1007/s10531-012-0319-x) contains supplementary material, which is available to authorized users. K. Y. Chong (&)  W. F. Ang  A. F. S. L. Lok  C. K. Yeo  R. T. Corlett  H. T. W. Tan Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore e-mail: kwek@nus.edu.sg S. M. L. Lee  A. T. Gwee  P. K. F. Leong  S. Ahmad Singapore Botanic Gardens, National Parks Board of Singapore, 1 Cluny Road, Singapore 259569, Singapore 123 Biodivers Conserv (2012) 21:2589–2599 DOI 10.1007/s10531-012-0319-x