Genetic connectivity in tropical and temperate Australian seagrass species

Kathryn McMahon, Elizabeth Sinclair, Kor Jent van Dijk, Udhi E. Hernawan, Jennifer Verduin, Michelle Waycott

Research output: Chapter in Book/Conference paperChapterpeer-review

9 Citations (Scopus)


Connectivity among populations influences resilience, genetic diversity , adaptation and speciation, so understanding this process is fundamental for conservation and management. This chapter summarises the main mechanisms of gene flow within and among seagrass meadows, and what we know about the spatial patterns of gene flow around Australia’s coastline. Today a significant body of research on the demographic and genetic connectivity of Australian seagrass meadows has developed. Most studies have focused on the genera Posidonia, Zostera, Heterozostera and Thalassia, in tropical and temperate systems across a range of habitats. These studies have shown overwhelmingly, that sexual reproduction is important for meadow persistence, as in most cases Australian seagrass meadows are genotypically diverse, with moderate to high levels of genotypic diversity. This high diversity could be generated through demographic connectivity, recruitment of individuals sourced from within a meadow, or from dispersal between meadows. Attempts to understand the relative significance of these processes are limited, highlighting a major gap in our understanding. Genetic structure is apparent across a range of spatial scales, from m’s to 100’s to 1000’s km. At local and regional scales, particularly in confined systems such as estuaries and bays, it is not necessarily the dominant oceanographic currents influencing patterns of genetic connectivity, but local eddies, winds and tides. Over larger spatial scales, isolation by distance is consistently significant, with unique genetic clusters spreading over 100s of kilometres. This indicates that regional structure occurs at the limits of long distance dispersal for the species and this is particularly evident where meadows are highly fragmented. The number of genetic studies on Australian seagrasses has increased dramatically recently; however, there are still many opportunities to improve our understanding through focusing on species with different dispersal potentials, more detailed sampling across a range of spatial and temporal scales and combining ecological and modelling approaches.
Original languageEnglish
Title of host publicationSeagrasses of Australia
Subtitle of host publicationStructure, Ecology and Conservation
EditorsAnthony W. D. Larkum, Gary A. Kendrick, Peter J. Ralph
Place of PublicationNetherlands
PublisherSpringer International Publishing
Number of pages40
ISBN (Electronic)9783319713540
ISBN (Print)9783319713526
Publication statusPublished - 27 Jul 2018


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