Introducing Devil’s Corner — a new saltmarsh site to explore on Moulting Lagoon, east coast Tasmania

Moulting Lagoon is a stunning estuarine wetland and Ramsar site, on the east coast of Tasmania, containing areas of temperate saltmarsh. In March 2025, NGT completed a desktop assessment to identify additional opportunities for hydrological restoration of wetlands and saltmarsh, in the peripheral areas of Moulting Lagoon. As many of you will know, we have also undertaken restoration works at nearby Long Point Reserve and The Grange, and also completed an eco-hydrological assessment for the adjacent Apsley Marshes Ramsar site. All of these projects have been undertaken for NRM South with funding provided by the Australian Government for the broader ‘Supporting Significant Wetlands’ project.

A desktop analysis was used to assess and map physical changes to the eco-hydrology of waterways, wetlands and saltmarsh in the periphery and lower catchment of Moulting Lagoon. Where feasible, site assessments were undertaken to ground truth these changes and determine the preliminary feasibility of restoration.

One of the areas identified as a priority for further assessment exists on the Devil’s Corner property, which adjoins the Apsley Marshes to the southwest. This property is already involved in broader land restoration works with NRM South and presents a clear opportunity to add hydrological restoration to current conservation activities. The property is largely dedicated to grape growing and wine making, however, it includes grazing and areas of remnant woodland and saltmarsh, including significant frontage on Moulting Lagoon.

Changes at the site were documented for two areas: one in the north and one in the south of the property.

Devil’s Corner North

The northern site comprises Top Hole, which receives freshwater inflows from a creek line to the north that appears to be channelised into, and possibly out of, the hole to Moulting Lagoon. Likewise, a separate waterway flowing from the north appears to have been cut directly through the extant saltmarsh into Moulting Lagoon.

The site is known to support native species such as the Australasian bittern, both Wedge-tailed and White-bellied eagles, as well as quolls and Tasmanian devils. It also supports saline sedgeland and succulent saline herbland vegetation communities.

Drains have been in place at this site since before 1948. A large dam, more recently constructed to support irrigation of the grapevines, has likely decreased freshwater inflows to the area. Drains cut through the hole linking associated waterways have likely fast-tracked the runoff of inflows from the north to the lagoon. Both of these developments have likely dried out a large area of the site. The culvert under the access track is also inappropriately sized, leading to increased permanency of Top Hole and unequalisation of flows and water level on either side during tidal ingress and freshwater inflow events.

The eastern wetland almost always holds water whereas areas to the north and west are dry. The eastern wetland may be more permanently inundated than under the natural scenario. Saltmarsh condition has suffered not only from eco-hydrological change, but also from a history of stock grazing.

Devil’s Corner South

The southern area comprises the large northern Middle Hole and smaller southern Bottom Hole, which resides in a drainage area somewhat separate to that of Top Hole (unless in periods of flood when the two likely combine). Middle Hole is fed by a series of freshwater inflows to the east and eventually drains into a bay of Moulting Lagoon. Middle Hole appears to have been drained to the lagoon via a single drain which crosses an access track. This area supports similar values to that of the north.

Drains have been in place prior to the 1948 imagery. Middle Hole still holds water, but the natural sill may have been lowered by the main drain. Middle Hole is now ephemeral and potentially drier compared to the natural scenario. Eastern areas are also now likely drier as a result of drainage.

The culverts under the access track are also impeding equalisation of flow and water level either side.

Next Steps

Restoration of these areas is highly feasible as the landholder is keen to support restoration efforts and minor infilling of drains is likely to improve saltmarsh outcomes as seen at other sites peripheral to Moulting Lagoon.

In June 2025 we developed and began implementing a monitoring plan for this property, focused on collecting baseline data on the hydrology, water quality and vegetation of each of the main holes and associated wetland/saltmarsh areas. Water level and salinity loggers were installed in June 2025 and vegetation transects will be monitored in summer 2025/2026. Photo points were also established in June 2025 to qualitatively monitor change over time in target areas.

Baseline information will help to provide insights into the current eco-hydrology of the site and will importantly provide comparative data with which to contrast before and after restoration outcomes, should restoration plans be developed and implemented in future. Sites will be monitored for the next 12 months to inform a restoration plan. This and other sites around Moulting Lagoon will continue to be assessed for the term of the project out to 2028 and beyond.

We look forward to gaining insights to the eco-hydrology of Devil’s Corner’s saltmarsh over the coming years, in conjunction with our project partners.

This project is funded by the Australian Government’s Natural Heritage Trust
and delivered by NRM South, a member of the Commonwealth Regional Delivery Partners panel.