Human impacts and saltmarsh loss in the Circular Head coast, north-west Tasmania, 1952– 2006: implications for management.

Abstract

Coastal saltmarshes of temperate Australia are in decline and have recently been listed as a threatened ecological community under Federal legislation. Further research is required to better understand both the extent and nature of their decline in order to plan their recovery. A case study is presented of the most extensive area of saltmarshes in Tasmania, on the north-west Circular Head coast. A mixture of aerial photographs and ground-truthing data were used to determine human impacts and saltmarsh loss between 1952 and 2006. There was an absolute loss of 219 ha since 1952, largely due to the effects of a 24.5 km network of levees. Of the 1 153 ha of saltmarshes that remained in 2006, a further 752 ha (65%) was associated with one or several of land-based human impacts. This left 401 ha (35%) of saltmarshes that had no recorded human impacts and a contiguous vegetative buffer zone of 50–100 m. These areas represent some of the least disturbed saltmarshes in Tasmania and warrant adequate conservation measures. Future planning for conservation and the use of land and marine resources should strive to promote both the extent and functional health of saltmarshes.