The South American seagrass <em>Zostera</em> <em>chiliensis</em>, endangered or invasive? — ASN Events

The South American seagrass Zostera chiliensis, endangered or invasive? (#61)

Craig DH Sherman 1 , Tim M Smith 1 , Paul H York 2 , Graeme C Hays 1 , Erik Van Sebille 3 4 , Nathan F Putman 5 , Martin Thiel 6 , Bernardo R Broitman 6 , Peter I Macreadie 1
  1. Deakin University, Waurn Ponds, VIC, Australia
  2. James Cook University, Townsville, QLD, Australia
  3. UNSW, Sydney, NSW, Australia
  4. UNSW, Sydney, NSW, Australia
  5. Oregon State University, Portland, Oregon, USA
  6. Facultad Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile

The seagrass Zostera chilensis is classified as an endangered species with only three known populations occurring along the coast of central Chile.  Recent molecular work has revealed no distinction between Z. chiliensis and the Australian seagrass Z. nigricaulis, suggesting a very recent introduction to Chile. Successful amplification of seagrass samples from Chile using species-specific microsatellite markers developed for Z. nigricaulis support the idea that Chilean populations are derived from Australia. Using a combination of molecular data, historical shipping records, fragment viability data and oceanic modeling, we explore the possibility of a trans-oceanic dispersal event spanning several thousands of kilometers, versus a human mediated introduction event via shipping. Levels of genotypic diversity and patterns of connectivity among the three isolated populations along the Chilean coast are also explored. The results from this study have important implications for understand how potentially rare (but important) trans-oceanic dispersal events can lead to establishment of new populations.