The East Coast Cape Barren Island Lagoons Ramsar site is located on the east coast of Cape Barren Island, one of the Furneaux Group of islands which lie in Bass Strait to the north-east of Tasmania. The site extends from just north of Tar Point down to Jamieson’s Bay and extends westwards from the coast for a distance varying from one to four kilometres. It comprises a complex of freshwater, brackish, saline and sometimes hypersaline lagoons, wetlands and estuaries that owe their existence to a dune system which has been slowly developing in an easterly direction, leaving shallow sandy soils, depressions and intermittently flowing water courses. The vegetation of the site is characterised by a tussock grassland of the exotic species Marram Grass on the foredunes, with a closed-scrub of Coastal Wattle, Prickly Moses and Marram Grass stabilising the hind dunes. Coastal Wattle, Silver Banksia and Southern Grass Tree form an open scrub on the sand plains behind these dunes, with further inland areas dominated by Manna Gum, Swamp Gum and Smithton Peppermint. This extensive system of shallow coastal lagoons contains a number of species that are considered to be of special botanical interest, including the Scarce Centrolepis which is rare at both a state and national level. Pointed Centrolepis, Sharpleaf Rush, Water Milfoil, Sago Pondweed, and Round-leaf Wilsonia are also found within the site. Locally significant numbers of duck species for the Flinders bioregion utilise this area. In addition, the Ramsar site is of great importance for the Hooded Plover. This area is of cultural importance to the local Indigenous community, who manage the freehold title to part of Cape Barren Island, including the Ramsar site. Access is currently restricted, keeping the site largely undisturbed, with a single bush track for 4WD vehicles providing access for duck hunters to Flyover Lagoon.
East Coast Cape Barren Island Lagoons
Government evidence of impact of climate change:
Australian Government, East Coast Cape Barren Island Lagoons Ramsar Site, Ecological Character Description
Six principal types of threat been entified for ECCBIL; fire; exotic species (flora; fauna); pathogens; inappropriate 4WD and other human access; climate change and grazing (Table 5 1).
Possible Immediate to medium term Increased sediment deposition and turbidity (run off) Nutrient enrichment Establishment of weeds Reduced habitat quality Change in floristics Likelihood Timing of threat Actual or likely threat of threatening activities Potential impact(s) to wetland components; processes and or services Already occurring Immediate to long term Climate change change in sea level; temperature and rainfall May influence wetland physical and chemical processes; groundwater discharge; the diversity of wetland types; wetland biology Change in the distribution and abundance of flora and fauna Change in the lifecycles of fauna (e.g. waterbird breeding; macroinvertebrates) Climate Human activity Increased wind Lower rainfall Uncontrolled Higher temperature Weeds and diseases fire Introduced animals stock 4 WD vehicles Loss of habitat with seasonal inundation Loss of deeper water Habitats Increased Hypersalinity Increased fire frequency and intensity Loss d diversity Exposure of sediments to wind rusion Soil compaction KEY Driver Stressor Ecological effect Figure 5 Stressor model for East Coast Cape Barren Island Lagoons Ramsar site (after Davis and Brock 2008) Due to the recent geomorphological process shaping the topography of the ECCBIL; one of the significant threats to the site is large scale destabilisation of the coastline.
Climate change The conceptual model of the site; Figure 4 1; demonstrates the significance of climate and its interaction with geomorphology and hydrology; at ECCBIL.
The diversity of wetland types and vegetation communities is sustained by this interaction and projected climate changes; such as changes in sea level; an increase in temperature; decline in rainfall and an altered seasonality of rainfall along with an increase in winds can produce cumulative effects.
Nevertheless; given the likelihood of changing climatic conditions combined with these threats; there is the potential for irreversible damage to the wetland system.
Table E.3 Major threatening activities identified for ECCBIL Actual or likely threat of Potential impact(s) to wetland components; processes and or threatening activities services Fire Removal of the vegetation and opening the underlying (increase in intensity and sediments to destabilisation by wind frequency) Increased fire frequency can cause changes in floristics to more fire tolerant species Loss of habitat; flora and fauna.
A history of high fire frequency and unplanned bushfires are a threat to the integrity of the vegetation communities. 2.
Fire frequency was not sufficiently high as to cause major impact since significant examples of undisturbed fire sensitive vegetation such as stands of unburnt large Oyster Bay pine (Callitris rhomboidea) remained.
Table 5 Threats to ECCBIL wetland system Likelihood Timing of threat Actual or likely threat of threatening activities Potential impact(s) to wetland components; processes and or services Already occurring Immediate to medium term Fire (increase in intensity and frequency) .
Removal of the vegetation and opening the underlying sediments to destabilisation by wind Increased fire frequency can cause changes in floristics to more fire tolerant species Loss of habitat; flora and fauna Competition with native flora and fauna Reduced habitat (i.e. choking of wetlands; changes in vegetation structure) Loss of native species Already occurring Immediate to medium term Exotic species introduction and spread of invasive species such as rabbits; feral turkeys; thistle; marram grass; and gorse Pathogens Already occurring Immediate to medium term Phytophthora cinnamomi can cause changes to floristics and structure of vegetation communities and potentially result in changes to wetland dynamics Chytrid fungus Batrachochytrium dendrobatidis Almost certain Vehicle access particularly four wheel drives Immediate to medium term Erosion and increased run off Increased turbidity Disturbance of native species Loss of habitat Loss of native species Introduction or spread of weed propagules and pathogens such as Phytophthora cinnamomi .
Loss of vegetation cover leading to dune mobilisation is likely to be attributable to excessive fire frequency (anthropogenic) impact of introduced species . inappropriate use of four wheel drives. 5.
Although some of the vegetation types are adapted to; or dependent upon; a certain fire frequency; some of ECCBIL has burnt with excessive frequency or intensity.
The biggest threat to the wetlands from fire is removal of the vegetation and exposure of the underlying sediments to destabilisation by wind. 5.
Critical service Natural or near natural wetland ecosystem Does not include the Ramsar wetland types rocky shores (D); sand shingle or pebble shores (E); or seasonal intermittent irregular rivers streams creeks (N) because the coastal land forms (D) and waterways (N) are natural formations which will not change significantly without human intervention whereas coastal shorelines (E) are likely to have a high natural variability depending on weather conditions (e.g. storm events).