Biogeography of Australian seagrasses: NSW, Victoria, Tasmania and temperate Queensland

This chapter presents an introduction to the biogeography of southeastern Australian seagrasses, explaining the distribution and basic ecology of the 22 species that inhabit this 10,000 km stretch of coastline, from the northern limit of Queensland's temperate zone through to Tasmania. The chapter draws on 25 years of new information (peer-reviewed literature, books, personal communications, etc.) that has been generated since the previous biogeography chapter of its kind was written by Larkum et al. (Biology of Seagrasses-a treatise on the biology of seagrasses with special reference to the Australian region. Elsevier, The Netherlands, 1989). The influence of local (e.g. geomorphic environment) and large-scale (e.g. temperature) factors on the distribution of species are discussed. Also, we present up-to-date information on the status (declining, increasing, or no change) of each species from a conservation point of view on a state-by-state basis. Not surprisingly, many species are reported to have declined for a variety of reasons, including: flood events, boat moorings, and coastal development (e.g. dredging). Fortunately, there are also reports of recovery. Thanks to developments in genetic sequencing we have been able to present new data on genetic connectivity, gene flow, and source-sink populations for a handful of species. In the coming years we expect and hope that improvements in remote sensing technology will allow for more accurate, more frequent, and higher resolution mapping of seagrasses along this stretch of coast.