Environ Monit Assess (2012) 184:625–635 DOI 10.1007/s10661-011-1991-0 Non-detection errors in a survey of persistent, highly-detectable vegetation species Kenneth D. Clarke · Megan Lewis · Robert Brandle · Bertram Ostendorf Received: 26 July 2010 / Accepted: 23 February 2011 / Published online: 22 March 2011 © Springer Science+Business Media B.V. 2011 Abstract Rare, small or annual vegetation species are widely known to be imperfectly detected with single site surveys by most conventional vege- tation survey methods. However, the detectabil- ity of common, persistent vegetation species is assumed to be high, but without supporting re- search. In this study, we evaluate the extent of false-negative errors of perennial vegetation species in a systematic vegetation survey in arid South Australia. Analysis was limited to the seven most easily detected persistent vegetation species and controlled for observer skill. By comparison of methodologies, we then predict the magnitude of non-detection error rates in a second survey. The analysis revealed that all but one highly detectable perennial vegetation species was im- perfectly detected (detection probabilities ranged from 0.22 to 0.83). While focussed in the Aus- tralian rangelands, the implications of this study K. D. Clarke (B ) · M. Lewis · B. Ostendorf The University of Adelaide, Adelaide, South Australia 5005, Australia e-mail: kenneth.clarke@adelaide.edu.au R. Brandle South Australian Department for Environment and Natural Resources, Science Resource Centre, Adelaide, South Australia 5000, Australia are far reaching. Inferences drawn from system- atic vegetation surveys that fail to identify and account for non-detection errors should be con- sidered potentially flawed. The identification of this problem in vegetation surveying is long over- due. By comparison, non-detection has been a widely acknowledged, and dealt with, problem in fauna surveying for decades. We recommend that, where necessary, vegetation survey methodology adopt the methods developed in fauna surveying to cope with non-detection errors. Keywords Non-detection · Vegetation survey Introduction Non-detection errors are a widely acknowledged problem in fauna surveys (Bunge and Fitzpatrick 1993; Colwell and Coddington 1994; Dorazio and Royle 2005; MacKenzie 2005; Mao and Colwell 2005), and many survey and analysis methods have been developed to counteract the influence of non-detections. The most common of these methods is repeat site visits within a relatively short time (MacKenzie et al. 2002; Tyre et al. 2003; Boudreau and Yan 2004; Gu and Swihart 2004; Field et al. 2005). However, non-detection is a se- rious and as-yet underappreciated problem in veg- etation surveying (Kéry and Schmidt 2008; Guoke