An overview of Australia's temperate marine phylogeography, with new evidence from high‐dispersal gastropods

Abstract

Aim We provide an overview of the location and ages of coastal phylogeographical breaks in southern Australian planktonic dispersers, and test the hypothesis that the absence of such breaks in some species is an artefact of insufficient resolution of genetic markers when such breaks evolved comparatively recently. Location Temperate coastal Australia. Methods We generated a large (> 1500 individuals) data set from rapidly evolving microsatellite markers for two codistributed Australian coastal gastropods, and compared it with mitochondrial DNA data. Both study species, the snail Nerita atramentosa and the limpet Siphonaria diemenensis, have long planktonic dispersal phases, and neither taxon exhibits substantial regional genetic structure on the basis of mitochondrial DNA. We tested for the presence of genetic structure by means of AMOVA, Bayesian clustering (structure) and iterated realloction (flock). Results There was no compelling evidence for the existence of more than one evolutionary lineage in either species. Main conclusions Discrepancies in the phylogeographical structuring of co‐distributed intertidal taxa cannot be attributed to insufficient marker resolution for the two species considered here, and likely reflect a combination of abiotic and biotic factors that include porous dispersal barriers, life history and species age/history. It appears that contemporary oceanography does not explain the presence of phylogeographical breaks, but may serve to maintain breaks that evolved earlier. Deep genetic divergence in some of the previously studied coastal invertebrates suggests that these could be cryptic species, in which case competitive exclusion may play a role in constraining species biogeography.

Seascape genomics reveals adaptive divergence in a connected and commercially important mollusc, the greenlip abalone (Haliotis laevigata), along a longitudinal environmental gradient

“…It has been proposed that greenlip abalone metapopulation structure varies among biogeographic regions and that data on life history and recruitment dynamics are needed for guiding regional sustainable management (Miller et al., ). This agrees with seascape genetic studies spanning the entire southern Australian coast which show that metapopulation connectivity and recruitment success in broadcast spawning intertidal organisms vary along the coast in part due to differences in on‐shelf oceanographic dynamics (Teske et al., , ). The genomewide signal consistent with stepping‐stone dispersal detected in our study emphasizes the importance of management policies aimed at maintaining demographically secure local subpopulations.…”

“…For southwestern Australia, if we consider only the periods relevant for the spawning and pelagic larval duration of greenlip abalone (Prince, Sellers, Ford, & Talbot, ; Shepherd, Lowe, & Partington, ), advection connectivity simulations suggest that >80% of larvae released along our study region will reach the boundary currents responsible for long‐distance transport (see supplementary material in Teske et al., ). Indeed, population genetic studies of intertidal organisms with contrasting life histories (e.g., kelps and snails) have shown that strong oceanographic currents along this coastal region can promote eastward dispersal from Cape Leeuwin towards the Great Australian Bight (Coleman, Feng, Roughan, Cetina‐Heredia, & Connell, ; Teske et al., ).…”

Phylogeography of the Hypnea musciformis species complex (Gigartinales, Rhodophyta) with the recognition of cryptic species in the western Atlantic Ocean

“…, Colgan , Teske et al. ) and around the Florida peninsula (e.g., algae, fishes, marine invertebrates, a coastal bird, and a coastal vascular plant species phylogeographic concordance; Gurgel et al. , Soltis et al.…”

Life‐history predicts past and present population connectivity in two sympatric sea stars

“…When sea levels fell to lower than 50 m below contemporary levels, a land bridge formed between Victoria and Tasmania in the present day area of Bass Strait. The emergence and subsequent submergence of the Tasmanian land bridge would have cut off circulation and gene flow between the Southern Ocean and the Tasman Sea, providing opportunities for reproductive isolation in refugia (Sinclair et al., ), differentiation via diversifying selection, and lineage extinctions (Teske, Sandoval‐Castillo, Waters, & Beheregaray, ). Several other species show strong genetic breaks or phylogenetic structure at this point (Ayre et al., ; Dawson, ; Sherman et al., ; Waters, ; Waters & Roy, ; York, Blacket, & Appleton, ).…”