Taxonomist survey biases and the unveiling of biodiversity patterns

Basic and applied studies based on biodiversity data need accurate information on the distribution of species. However, several studies clearly show that this information is frequently biased, mainly as a consequence of aggregated survey patterns in which taxonomists repeately select localities with specific characteristics. In this study, we have constructed three different but simple virtual species richness scenarios to simulate the capacity of random, aggregated or regular survey designs to reveal the true biodiversity pattern. We are specifically interested in the effect of taxonomist insistence on surveying those localities that guarantee success in the collection of as many species as possible (species richness bias), and on the coordinated or uncoordinated character of the efforts carried out by the whole community of taxonomists. In all simulated species richness scenarios, a survey directed towards those localities that were previously recognized as having a higher species richness value is not recommended if the aim is to recover the true geographical pattern of species richness in a given territory. This aggregated process of allocating survey localities is probably caused by the primary aim of taxonomists, which is to acquire specimens of rare species and/or as many species as possible. However, an increase in taxonomist curiosity towards non-surveyed localities near those previously identified as the richest allows one to obtain better results, provided that the species richness pattern is not too patchy and tie effort for discovering the true map is not too difficult. Our results suggest that planned survey designs are necessary when most of the data comes from studies not specifically designed to reveal the distribution of biodiversity. The capacity of this data to represent the real geographical pattern of biodiversity may depend on the capacity of the taxor omist community to be self-motivated. (C) 2008 Elsevier Ltd. All rights reserved.