The five species of seagrass occuring around the coast of Tasmania were located on a presence-absence basis. Sampling included the recording of species, depth, density, substratum and presence of algal epiphytes. Available aerial photography from three time periods (circa 1950, circa 1970 and circa 1990) was used to digitally map selected beds into a GIS using ARC/INFO. Sample site attributes were added to the database and patterns of change and distribution were analysed and mapped. An area of approx. 220 square kilometres was mapped leading to an estimate of between 400 and 500 square kilometres of seagrass occurring in Tasmania. Decline has occurred, particularly close to areas of human population and activity. The report proposes mechanisms for the management and protection of Tasmania's seagrass communities, and nominates representative areas for possible reserve status. Reference: Rees, CG 1994 Tasmanian Seagrass Communities, Masters Thesis, Centre for Environmental Studies, Department of Geography and Environmental Studies, University of Tasmania. Department of Geography and Environmental Studies, University of Tasmania.

The data was originally captured from aerial photography and digitised using a LIS 1:25,000 Tasmanian coastline as a base

Position Accuracy: A best estimate puts the data at about the 1:25,000 level of accuracy. Attribute Accuracy: While the attributes were attached using carefull error checking procedures there is no available estimate of error levels. Logical Consistency: All data is checked for undershoots, overshoots, duplicate elements, accurate symbology and free endpoints by both visual and automated means. Completeness: The Tasmanian mainland and major islands. However, it is emphasised that the absence of data for any area does not mean there is no seagrass there. This is because the sampling program was not exhaustive and also some areas did not have suitable data sources available