Monitoring the effects of grazing exclusion on saltmarsh regeneration at Moulting Lagoon, Tasmania

Saltmarsh restoration programs are increasing being been funded through various mechanisms and commonly involve fencing out of livestock to allow for the passive regeneration of saltmarsh vegetation. Australian Government through its National Landcare Program provided a grant to improve the ‘ecological character’ of Moulting Lagoon Ramsar Site, east coast of Tasmania, through saltmarsh restoration involving fencing, de-stocking, and cessation of grazing. As part of this project, a monitoring regime was established by surveying vegetation and habitat condition on semi-permanent transects at the restoration site and at an adjacent control site within a privately protected area to evaluate the extent to which restoration contributed to observed changes. Monitoring results show that restoration has facilitated the initial recovery of saltmarsh vegetation, with a slight decrease (3%) in bare ground cover after 2 years, largely due to the expansion of the early-successional groundcover, Sarcocornia quinqueflora (2% average increase). The late-successional habitat-forming species, Tecticornia arbuscula, showed limited signs of recovery (i.e. increase in percent cover and plant height). There was also a slight increase in species richness attributable to restoration. In addition, an active restoration technique was trialled using mulch and hessian cloth to inflate the marsh surface and promote faster recovery of the saltmarsh. Results from these trails showed an increase in plant cover of 12% in the plots subjected to the experiment with the control plots having limited recovery (2% increment in S. quinqueflora). Findings from this study indicates that bare ground, species richness and the cover of the most dominant species are sensitive indicators to de-stocking, and hence could be used as early indicators for monitoring. The use of active restoration techniques, such as the sediment inflation trial, could be further encouraged and replicated for areas heavily degraded by stock, as it substantially contributes to a faster recovery of the vegetation.