news and update Purves, D. W., Lichstein, J. W., Strigul, N. & Pacala, S. W. (2008) Predicting and understanding forest dynamics using a simple tractable model. Pro- ceedings of the National Academy of Sciences USA, 105, 17018-17022. Ricklefs, R. E. (2008) Disintegration of the ecological community. American Naturalist, 172, 741-750. Ricklefs, R. E. (2009) A brief response to Brooker et al.'s comment. American Naturalist, 174, 928-931. Vellend, M. (2010) Conceptual synthesis in community ecology. Quarterly Review of Biology, in press. ISSN 1948-6596 Robert P. Freckleton Department of Animal & Plant Sciences, Uni- versity of Sheffield, UK e-mail: r.freckleton@sheffield.ac.uk http://www.shef.ac.uk/aps/staff/acadstaff/ freckleton.html Edited by Frank A. La Sorte symposium summary The importance of being small: does size matter in biogeogra- phy? One-day symposium at Systematics, the First BioSyst conference – Leiden, The Netherlands, 13th August 2009 Since the 18th century, scientific expeditions in remote places have discovered new species and even new orders and new classes of macro- organisms with limited distribution. In contrast, scientists have discovered that microscopic organ- isms found in remote places could be mostly as- cribed to taxa already known in their home coun- tries. This idea was encapsulated by Beijerinck (1913) and Baas-Becking (1934), and became known as the ‘everything is everywhere’ (EisE) hypothesis: micro-organisms are globally distrib- uted due to their potential for long-range disper- sal (Kellogg and Griffin 2006) and large abun- dances (Finlay 2002). The assumption that organ- isms smaller than 2 mm are cosmopolitan in their distribution is best supported when species are defined using traditional taxonomy based on mor- phological characters. However, the EisE hypothe- sis has been challenged recently as molecular evi- dence has revealed a high degree of cryptic diver- sity, restricted dispersal and phylogeographic pat- terns in a variety of microscopic organisms, includ- ing both prokaryotes and eukaryotes (e.g. Martiny et al. 2006, Green et al. 2008). The recent debate on the EisE hypothesis began after the contributions by Finlay and Fenchel (e.g. Finlay and Clarke 1999, Finlay 2002, Fenchel and Finlay 2004), and different research groups are currently trying to test its reliability on different model organisms. Thus, it was consid- ered timely to organize a full-day symposium on this topic, and that was held during the BioSyst meeting in Leiden, a joint conference of all the European systematics associations. The current debate on the EisE hypothesis divides scientists in two major groups (Whitfield 2005). One group follows the EisE hypothesis in its original form, assuming that species differences in samples from different areas occur because of environmental differences, and not because of restricted dispersal. Thus, ‘everything is every- where, but the environment selects’ is considered the rule for micro-organisms. The other group proposes that traditional taxonomy of microscopic organisms based only on morphological charac- ters is not able to resolve their actual diversity, and cosmopolitan ranges therefore result from misidentification and lumping of spatially isolated lineages. Thus, cosmopolitanism is considered an exception in micro-organisms, as it is in macro- organisms. It has been suggested that the EisE hy- pothesis incorporating environmental selection may be difficult to falsify because of unmeasured aspects of the environment that differ consis- tently among regions (Foissner 2006). However, if we assume a dense sample of equivalent habitats across sampling regions, the hypothesis makes clear predictions about genotype distributions. If EisE is the rule, the degree of genetic relatedness between two individuals should be independent of the geographical distance between them. Con- versely, if EisE does not hold true, spatially explicit models should work in the same way as they do for macro-organisms, and genetic diversity should be related to geographical distances by a classical © 2009 the authors; journal compilation © 2009 The International Biogeography Society — frontiers of biogeography 1.2, 2009