Local habitat distribution determines the relative

Authors: Mark J A Vermeij Stuart A Sandin Jameal F Samhouri

Publish Date: 2006/09/27

Volume: 21, Issue: 1, Pages: 27-47

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Abstract

We investigate the relationship between habitat heterogeneity and morphological variation in the Caribbean coral speciescomplex Madracis pharensis/decactis This complex showed strong but incomplete morphospecies habitatmatching on a small spatial scale We find that only one Madracis morphospecies dominates in environments consisting of either few vertical or few horizontal habitats whereas in environments consisting of a mixture of horizontal and vertical habitats both morphospecies are common We demonstrate that the observed patterns of morphospecies habitatmatching cannot be explained by a pure polyphenic model where morphological variants are induced by a genotypebyenvironment interaction at their settling site Instead we suggest that habitatmatching results in whole or in part from genetically predetermined factors We present support for the hypothesis that this pattern of habitatmatching is due to habitat and morphospeciesspecific selective factors Our study describes how a variable environmental factor ie habitat distribution has a nonlinear effect on the spatial distribution of these morphospecies thereby influencing the genetic organization of the Madracis coral complex at the ~+1–10 km spatial scaleWe thank the following people for assistance in the field S “Henano’’ Hamilton Bryce Anderson N Johansen E Sampayo A Engelen A “Wrasse’’ Rassweiler and S Gladding The Carmabi Foundation provided logistical support J Dushoff J Regetz M Hellberg M van Oppen R Bak L Spinney J Wilder and I Baums are thanked for their assistance during various stages of this project Comments by M Dijksman and two anonymous reviewers greatly helped us to improve an earlier version of our ms We are grateful to the Royal Dutch Academy of Sciences KNAW for financial support to MJAV This is Dweezendputen contribution 1A

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