Genetic differentiation between estuarine and open coast ecotypes of a dominant ecosystem engineer

Melinda A. Coleman, J. S. Clark, M. A. Doblin, M. J. Bishop, B. P. Kelaher

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)


    Temperate intertidal shores globally are often dominated by habitat-forming seaweeds, but our knowledge of these systems is heavily biased towards northern hemisphere species. Rocky intertidal shores throughout Australia and New Zealand are dominated by a single monotypic species, Hormosira banksii. This species plays a key role in facilitating biodiversity on both rocky shores and estuarine habitats, yet we know little about the processes that structure populations. Herein we characterise the genetic diversity and structure of Hormosira and demonstrate strong restrictions to gene flow over small spatial scales, as well as between estuarine and open coast populations. Estuarine ecotypes were often genetically unique from nearby open coast populations, possibly due to extant reduced gene flow between habitats, founder effects and coastal geomorphology. Deviations from random mating in many locations suggest complex demographic processes are at play within shores, including clonality in estuarine populations. Strong isolation by distance in Hormosira suggests that spatial management of intertidal habitats will necessitate a network of broad-scale protection. Understanding patterns of genetic diversity and gene flow in this important ecosystem engineer will enhance the ability to manage, conserve and restore this key species into the future.

    Original languageEnglish
    Pages (from-to)977–985
    Number of pages9
    JournalMarine and Freshwater Research
    Issue number7
    Early online date18 Sept 2018
    Publication statusPublished - Jun 2019


    • asexual
    • clonality
    • diversity
    • foundation species
    • gene flow
    • Hormosira banksii
    • intertidal


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