Duck Bay Rice Grass (Spartina) Removal — Saltmarsh and Fish Habitat Recovery in North-West Tasmania

Rice grass (Spartina anglica), introduced to Tasmania from the 1930s, had overgrown more than 500 ha of saltmarsh at Duck Bay near Smithton. A large control programme funded by the Australian Government, led on the ground by Circular Head Landcare Group using herbicide applied by drone, quad bike and backpack, treated the infestation from 2020.
University of Tasmania researchers (Dr Vishnu Prahalad and colleagues) monitored vegetation and fish before and after treatment at two contrasting sites. Rice grass died back almost completely and was replaced by native vegetation dominated by Sarcocornia quinqueflora. Three years after treatment fish species more than doubled from 5 to 11 at Duck Bay and numbers rose about twentyfold; at Morgans Bay, where fish were almost absent before treatment, 255 fish per 100 m2 were recorded by 2023, comparable to nearby undisturbed marsh.
The results, published in Austral Ecology, are among the first in the southern hemisphere to document recovery of saltmarsh vegetation and fish habitat function after invasive grass removal. Limitations: the evidence is before-after at two sites with a three-year horizon, carbon and long-term re-invasion were not quantified, and herbicide use needs ongoing monitoring.

Read the full analysis: https://www.utas.edu.au/about/news-and-stories/articles/2026/rice-grass-took-over-a-tasmanian-wetland-for-decades.-scientists-finally-have-proof-it-can-come-back