Abstract
Major disjunctions among marine communities in southeastern Australia have been well documented, although explanations for biogeographic structuring remain uncertain. Converging ocean currents, environmental gradients, and habitat discontinuities have been hypothesized as likely drivers of structuring in many species, although the extent to which species are affected appears largely dependent on specific life histories and ecologies. Understanding these relationships is critical to the management of native and invasive species, and the preservation of evolutionary processes that shape biodiversity in this region. In this study we test the direct influence of ocean currents on the genetic structure of a passive disperser across a major biogeographic barrier. Donax deltoides (Veneroida: Donacidae) is an intertidal, soft-sediment mollusc and an ideal surrogate for testing this relationship, given its lack of habitat constraints in this region, and its immense dispersal potential driven by year-long spawning and long-lived planktonic larvae. We assessed allele frequencies at 10 polymorphic microsatellite loci across 11 sample locations spanning the barrier region and identified genetic structure consistent with the major ocean currents of southeastern Australia. Analysis of mitochondrial DNA sequence data indicated no evidence of genetic structuring, but signatures of a species range expansion corresponding with historical inundations of the Bassian Isthmus. Our results indicate that ocean currents are likely to be the most influential factor affecting the genetic structure of D. deltoides and a likely physical barrier for passive dispersing marine fauna generally in southeastern Australia.
Highlights
In many regions of the world discrete faunal boundaries have been identified in marine communities, including the Isthmus of Panama (Knowlton and Weigt 1998; Lessios 2008), the Sunda and Sahul shelves (Lohman et al 2011), and the Benguela upwelling (Gibbons et al 2010)
Ecology and Evolution published by John Wiley & Sons Ltd
We conclude that the major ocean currents of southeastern Australia influence the contemporary structure of D. deltoides by limiting east-west dispersal of planktonic larvae across Bass Strait
Summary
In many regions of the world discrete faunal boundaries have been identified in marine communities, including the Isthmus of Panama (Knowlton and Weigt 1998; Lessios 2008), the Sunda and Sahul shelves (Lohman et al 2011), and the Benguela upwelling (Gibbons et al 2010). Thermal gradients, habitat discontinuities, and paleo-land connections are recognized as some of the potential physical factors driving biogeographic structuring in these regions. The extent to which species ranges and gene flow are influenced by these factors is generally limited by species life history traits and ecology (Avise 1996; Sivasundar and Palumbi 2010; Luiz et al 2012). Understanding the link between biological and physical factors that limit species dispersal and colonization is critical for natural resource management. This provides a framework for managing threatened, invasive, and commercially important species, and insight into how ecological communities are likely to respond to environmental disturbances (e.g., climate change).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
