Flood Plain Lower Ringarooma River Ramsar site Ecological Character Description March 2012 Blank page Citation
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List of Abbreviations
Executive SummaryBackground Australia, as a contracting party to the Ramsar Convention on Wetlands, must meet specified obligations in the maintenance of the ecological character of its Wetlands of International Importance (Ramsar sites). An Ecological Character Description (ECD) is one of the management tools used in the protection of Ramsar sites. An ECD of a Ramsar site must support the requirements of the Ramsar Convention to maintain ecological character of Ramsar sites, as well as provide site-specific objectives based on the intrinsic social, cultural and environmental features of the site. The preparation of an ECD assists management of the wetland, including information required to:
The process for preparing an ECD can also engage the relevant stakeholders, thereby laying the foundations for alignment of goals and agreed management outcomes. The Flood Plain Lower Ringarooma River Ramsar site (‘the site’) was first listed in November 1982. General Site Description The site covers an area of 3519 hectares near the coast of north-eastern Tasmania, near the towns of Bridport and Gladstone. At its northern edge, the site includes the Boobyalla Inlet estuary and a mobile sand dune system. The site extends a distance of approximately eight kilometres to the south, encompassing a variety of habitats including a mosaic of freshwater wetlands which are significant to a number of species. The ecological data available for the site are very limited with the exception of a detailed vegetation survey covering much of the Flood Plain vegetation, and some geomorphic examination of the landforming processes within the site. There are several documents that provide some qualitative information on the site’s ecological character. The available information was supplemented with a field inspection by the study team and steering committee, as well as a flight over the site to increase understanding of the site’s physical geography. Information gained from the site inspections was used with aerial photography and the vegetation survey of part of the site to produce a vegetation map of the whole site. This provided the only quantitative data available for the ECD. The site can be separated into three zones – a coastal zone, an estuary zone and an aquatic (freshwater) zone. The coastal zone covers the entire coast of the site (three to four kilometres), including the combined mouth of the Boobyalla and Ringarooma Rivers and their delta. The Ramsar wetland types that occur within the coastal zone are: sandy shores (wetland type E); delta (wetland type F); and intertidal mud and sand flats (wetland type G). A number of beach nesting shorebirds have been recorded breeding on the beaches of the site, comprising the little tern (Sterna albifrons), hooded plover (Thinornis rubricollis), fairy tern (Sterna nereis), pied oystercatcher (Haematopus longirostris) and red-capped plover (Charadrius ruficapillus). The estuary zone is wave dominated, with a flood tide delta. Wave dominated deltas are considered ‘mature’ in terms of evolution and tend to be morphologically stable (assuming stable sea levels). They often have a narrow entrance which can restrict marine flushing, although this is counter-balanced by high river flows that expel marine water and flush material from the delta. The short residence time for deposited material results in little processing or trapping of associated nutrients and contaminants. The Ramsar wetland types that occur within the estuary zone include estuarine waters (wetland type F); intertidal mud and sand flats (wetland type G); intertidal salt marshes (wetland type H); and coastal brackish/saline lagoons (wetland type J). Typical of wave dominated delta estuaries, the Ringarooma estuary has a direct connection between river and sea, via a channel flanked by a low-lying vegetated Flood Plain. The channel is kept open by the relatively high river velocities and a dune barrier partially constricts the estuary entrance, preventing it from expanding into a large, open estuary. The ‘mature’ nature of wave dominated deltas means that they have been mostly filled by sediments. In the case of the Ringarooma estuary, this ‘maturation’ has probably been created prematurely through an increased rate of sediment yield from the catchment as a result of tin mining during the late 1800s and early 1900s. The freshwater zone contains wetlands formed on a lowland Flood Plain that widens out downstream of a shallow and constricted valley. In the wider and flatter area of the Flood Plain, water from high flows sometimes leaves the channel and spreads out, filling in depressions in the landscape. As the water leaves the channel during high flows it quickly loses velocity and deposits the heavier sediment along the channel edge, forming natural levees. These natural levees impede the water from subsequently returning to the channel, leaving it to form a mosaic of seasonally-inundated and permanent water bodies. The Ramsar wetland types that occur within the freshwater zone include: seasonal waterways (wetland type N); permanent freshwater marshes, pools and ponds (below 8 hectares), with emergent vegetation (wetland type Tp); seasonal freshwater marshes and pools, including seasonally flooded meadows and sedge marshes (wetland type Ts); shrub-dominated wetlands (wetland type W); and freshwater, tree-dominated wetlands (freshwater swamp forest) (wetland type Xf). The freshwater wetland complex is surface water dominated. Local groundwater appears to be controlled by river flows and floods, with the surface water generally recharging the local groundwater. The site’s hydrology is therefore dependent on the Ringarooma River and several small tributaries to the site. The wetlands are generally shallow and clear, providing ideal conditions for submerged and emergent macrophyte vegetation. The extent and period of inundation varies substantially across the site’s wetlands with corresponding variations in abundances and distributions of plant species. The water quality data from the Ringarooma River suggests that the wetlands’ water is of high quality for aquatic ecosystems, with low nutrients, low salinities and near-neutral pH. The bulk of the wetland area is altered from its natural condition. This has resulted from large-scale sedimentation arising from mining operations in the late 1800s and early 1900s. However, the large trees on the site, as well as aerial photographs over several decades show that many of the current conditions have been established for decades and sediment movement is no longer as dynamic as it once was. Therefore, current condition of the site is likely to be indicative of the condition at the time of listing. Areas that remain relatively unaffected by this mining-induced sedimentation include Bowlers Lagoon (a dune-barred lake in the sand sheet behind Boobyalla Beach) and some deflation hollows with associated lunettes. The site is at significant potential risk from the disturbance of acid sulphate soils. Sources of sulphide include seawater and sediments derived from mining. While the sediments are identified as “potential”, there is a risk of increased acidification of the soil and of the drainage waters from these soils if any groundwater extraction or local drainage systems lead to a lowering of the groundwater table and exposure of the potential acid sulphate soils to oxidation.
The site is currently listed against the following criteria: Criterion one: A wetland should be considered internationally important if it contains a representative, rare, or unique example of a natural or near-natural wetland type found within the appropriate biogeographic region. The Flood Plain Lower Ringarooma River Ramsar Site is rare within the bioregion (Tasmania Drainage Division, Commonwealth of Australia 2010; Bass Strait IMCRA Province, Commonwealth of Australia, 2006). The site contains good condition, regionally representative examples of wetland systems within a Flood Plain, with a mosaic of permanent and seasonal marshlands and a large river estuary (Boobyalla Inlet). Boobyalla Inlet is recognised as a Tasmanian estuary with high conservation significance (Edgar et al. 1999). Wetland vegetation communities recognised as threatened under Tasmanian legislation (DPIW 2007) and the site contains various wetland types which support these communities (DPIW 2006). These include Ramsar wetland types:
Criterion two: A wetland should be considered internationally important if it supports vulnerable, endangered, or critically endangered species or threatened ecological communities. The site supports six fauna species listed on the IUCN redlist or as nationally threatened under the EPBC Act, including four wetland-dependent species:
Criterion three: A wetland should be considered internationally important if it supports populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region. This criterion includes consideration of the site’s regional biodiversity, including biodiversity ‘hotspot’ status and regional endemism. The site has been described as important due to its diverse invertebrate fauna (RIS 2005). The series of shallow freshwater lagoons at the site are an important feeding and nesting place for many species of waterbirds. Approximately three kilometres of beaches are included in the site, from which a number of shorebirds have been recorded, including the hooded plover (Thinornis rubricollis), red-capped plover (Charadrius ruficapillus), greenshank (Tringa nebularia), red-necked stint (Calidris ruficollis), ruddy turnstone (Arenaria interpres), curlew sandpiper (Calidris ferruginea), black-fronted dotterel (Elseyornis melanops) and fairy tern (Sterna nereis) (Sally Bryant, personal communication). Approximately forty species of wetland dependent plants have been recorded at the site. Species considered rare or threatened in the bioregion contribute to the justification of this criterion. The site provides wetland habitat for two regionally threatened bird species and four regionally listed flora species considered to be at risk in the bioregion (Tasmania). These are:
An assessment of the remaining Ramsar listing criteria was undertaken to determine whether the site meets any criteria beyond the original listing. The assessment determined that the site also meets criterion four. Criterion four: A wetland should be considered internationally important if it supports plant and/or animal species at a critical stage in their life cycles, or provides refuge during adverse conditions. A number of migratory birds have been recorded from the site, including eleven migratory birds listed in CAMBA, JAMBA, ROKAMBA and/or the CMS. The site also provides support for five nesting shorebirds at a critical stage of their life cycle: breeding, including the little tern (which has migratory listing as noted above), and the fairy tern (IUCN red listed, as noted above). Tasmanian mudfish (Galaxias cleaveri), Tasmanian whitebait (Lovettia sealli) and Australian grayling (Prototroctes maraena) have been recorded in the Ringarooma River. These species all migrate between fresh and marine waters. These species highlight the importance of the estuarine habitat provided by the site and constitutes support for these species during a critical stage of their life cycles. This criterion is therefore met by the site and should be added to the listing criteria. Benefits and Services of the Site Although the site performs a range of benefits and services, the critical benefits and services of the site were identified as:
Critical Components and Processes of the Site Using SEWPaC recommended determinants, the following components and processes were identified as critical to the Flood Plain Lower Ringarooma River Ramsar Site:
Conceptual Models of the Site The Flood Plain Lower Ringarooma Ramsar Site encompasses several integrated ecosystems, including at least eleven identified Ramsar wetland types encompassing the river/Flood Plain/wetland complex, estuary, coast, dunefields, terraces and sand plains. These features are displayed in Figure E1, below. 
Figure E1: Broad ecological zones (and Ramsar wetland types) across the Flood Plain Lower Ringarooma Ramsar Site. The key features of the landscape conceptual model include the river within its flood plain, surrounded by heathland and marshes, breaking out of its channel at some points and discharging into lagoons, before reaching the estuary near the dune barrier (Figure E2). Within the area of estuarine influence, the channel widens and is bounded by a saltmarsh on part of its northern bank before reaching a developing central basin and discharging over the delta into Ringarooma Bay. Threats to the Site’s Ecological Character Climate change was identified as the largest threat to the site’s coastal zone. The major threats to the estuary zone were identified as:
Direct threats to the freshwater zone of the site include:
Figure E2: Natural processes, systems and impacts within the Ringarooma Ramsar Site Limits of Acceptable Change Limits of Acceptable Change (LACs) were derived for each of the critical components/processes and benefits and services identified. The LACs derived for each of the nine components/processes are:
Explanatory Notes on LACs:
Changes in Ecological Character since Listing Although there have been changes to the site between listing and present day, it is difficult to argue that these are a change in ecological character of the site. The site features that supported its listing remain, apart from an increase in sedgeland/rushland. Further, the limits of acceptable change that have been derived are applicable to the site at the time of listing, except for the increased area requirement for the sedgeland/rushland. Encroachment of irrigated pasture is a serious, on-going and expanding cause for concern for the ecological character of the site. This has occurred on land classed as ‘agricultural land’ that was previously dry-grazed. If not controlled, this activity may change the site’s ecological character by altering the vegetation communities through the introduction of pasture or weed species. The sedimentation from mining waste has also moved further into the site between listing and present day. Advances of sediment into Shantys Lagoon indicate that small areas of the wetland have been altered (to other wetland types) since listing. This process is ongoing and is likely to continue for several decades.
There is a general paucity of baseline data at the site, and for the ecological character to be defined in a quantitative way, there needs to be a more strategic collection of a baseline. Data should be gathered using standard methods that allow comparisons to future monitoring programs. The initial sampling strategy design must be cognisant of repeatability. The data should also be gathered using similar approaches and methods comparison with other Tasmanian data sets and the rest of Australia, to facilitate comparisons and assessment of communities. Community Education and Public Awareness (CEPA) The primary messages to be communicated to relevant stakeholders are:
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