Genetic relatedness does not retain spatial pattern across multiple spatial scales: dispersal and colonization in the coral, Pocillopora damicornis KELVIN D. GOROSPE and STEPHEN A. KARL Hawai‘i Institute of Marine Biology, University of Hawai ‘i, M anoa, PO Box 1346, K ane ‘ohe, HI, 96744, USA Abstract Patterns of isolation by distance are uncommon in coral populations. Here, we depart from historical trends of large-scale, geographical genetic analyses by scaling down to a single patch reef in K ane‘ohe Bay, Hawai ‘i, USA, and map and genotype all colonies of the coral, Pocillopora damicornis. Six polymorphic microsatellite loci were used to assess population genetic and clonal structure and to calculate individual colony pair- wise relatedness values. Our results point to an inbred, highly clonal reef (between 53 and 116 clonal lineages of 2352 genotyped colonies) with a much skewed genet frequency distribution (over 70% of the reef was composed of just seven genotypes). Spatial autocorrelation analyses revealed that corals found close together on the reef were more genetically related than corals further apart. Spatial genetic structure disap- pears, however, as spatial scale increases and then becomes negative at the largest dis- tances. Stratified, random sampling of three neighbouring reefs confirms that reefs are demographically open and inter-reef genetic structuring was not detected. Attributing process to pattern in corals is complicated by their mixed reproductive strategies. Sepa- rate autocorrelation analyses, however, show that the spatial distribution of both clones and nonclones contributes to spatial genetic structure. Overall, we demonstrate genetic structure on an intrareef scale and genetic panmixia on an inter-reef scale indicating that, for P. damicornis, the effect of small- and large-scale dispersal processes on genetic diversity are not the same. By starting from an interindividual, intrareef level before scaling up to an inter-reef level, this study demonstrates that isolation-by-distance patterns for the coral P. damicornis are limited to small scales and highlights the importance of investigating genetic patterns and ecological processes at multiple scales. “Everything is related to everything else, but near things are more related than distant things”. Tobler’s first law of geography (Tobler 1970) Keywords: coral reproduction, lace coral, landscape genetics, larval dispersal Received 7 September 2012; revision received 27 March 2013; accepted 29 March 2013 Introduction Scale is of central concern in ecology because it sets the spatial and temporal context of the natural phenome- non being described (Wiens 1989; Levin 1992). The importance of scale can be illustrated by the phenomenon of coral bleaching whereby corals and the symbiotic algae from which they derive most of their nutrients become decoupled. On a large-scale, mass-bleaching events affecting whole reefs and atolls can be explained by large-scale (e.g. ocean basin wide) elevated sea tempera- tures. On a smaller scale (e.g. metres or centimetres), however, bleaching can manifest itself as a patchy phe- nomenon, affecting some colonies on a reef but not others. Explanations of small-scale bleaching, therefore, Correspondence: Stephen A. Karl, Fax: (808) 236 7443; E-mail: skarl@hawaii.edu © 2013 John Wiley & Sons Ltd Molecular Ecology (2013) 22, 3721–3736 doi: 10.1111/mec.12335