ISSN 1948-6596 news and update commentary Diversity and uniformity of island floras Studies of the ecological, evolutionary and bio- geographic patterns of island organisms have played an enormous role in concept shaping and theory forming in ecology, evolutionary science and biogeography. Numerous observations and descriptions of strange island beings, stunning evolutionary radiations and robust empirical for- mulae (e. g. on species–area relations) led to the insightful and influential syntheses of Mayr, Pre- ston, Carlquist, Williams, MacArthur and Wilson and others. Such works have been seminal for thousands of descriptive, explorative, hypothesis- driven and even experimental papers on island peculiarities, island evolution, interaction webs, and dispersion and distribution of species. Excel- lent reviews and textbooks on these subjects have been published with focus on each of these ap- proaches; today island ecology, evolution and bio- geography are a very vital and diverse part of ecology. The special issue “Comparative ecological research on oceanic islands”, edited by Christoph Kueffer and Jose-Maria Fernandez-Palacios in Per- spectives in Plant Ecology, Evolution and Sys- tematics (Vol. 12 iss. 2, April 2010), follows the tradition of tackling the subject from a focussed viewpoint. This time the focus is on island floras, and for once the scale is genuinely macroecologi- cal. All the papers involve as many islands or archi- pelagos as possible and attempt to make truly comparative analyses between them – to recog- nize patterns, and in some cases even to suggest explanations for the revealed pattern. The papers demonstrate that island ecology has come a long way from when it was a matter of finding strange plants or animals on remote islands (e.g. dodos), or amazing pedigrees in archipelago lineages (e.g. finches), or odd organismal interactions (e.g. ma- rine iguanas), or gross species numbers (“the holy S”). The editorial prelude by Kueffer and Fernandez-Palacios (2010), is a good introduction that tunes the ear to the harmonies and dishar- monies of island floras, as performed for us in the five subsequent articles. The main tune is that there are many ecological and biogeographical island and archipelago data and analyses avail- able, but few attempts at global syntheses. So, they argue, we should push “towards a common research agenda among biogeographers and ecologists in oceanic island research”. I applaud that. I certainly also appreciate the minor-tuned finale: we should do it before it is too late! The first two papers are truly island bio- geographic papers, focusing on species diversities. Chiarucci et al. (2010) aim to compare the floras of six well-known oceanic archipelagos. They try to take the very important step from species rich- ness (“the holy S”) to other measures of diversity. I find particularly interesting how they tackle beta diversity – so as to extract much more information from the species occurrence matrix than classic analyses of relations between island species num- ber (S) and area, or isolation, or altitude. Their approach is to make additive partitions between the alpha, beta and gamma diversities. This is a step forward but no leap: in their calculations they actually only apply total diversity for the entire archipelago (gamma), the mean S of the islands (alpha) and the difference between S max (the S of the richest island) and S i . In the species occur- rence matrix there is a wealth of information on beta diversity in the number of common species for each pair of islands; this information is not in- corporated in their approach. Whether step or leap, I find their paper stimulating and I am con- vinced that the last word on beta diversity in ar- chipelagos has not yet been uttered. Dominguez Lozano et al. (2010) compare the Canarian and Hawaiian archipelagos. Their comparisons concern both the entire floras and the floral composition of prominent habitat types. They consider taxonomic evenness, expressed as an index of the distribution the species within families and genera, and phylogenetic diversity (average taxonomic distinctness and the variance of the taxonomic distinctness). The authors con- vincingly show differences between the archipela- © 2010 the authors; journal compilation © 2010 The International Biogeography Society — frontiers of biogeography 2.3, 2010
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