Cobourg Peninsula

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We took care to attach appropriate images that are as close to representative of each species as our resources and the availability of images allowed. however, we could not ensure perfect accuaracy in every case. Some images show species that share the same genus but not at the species or subspecies level.

The Cobourg Peninsula is located 200 km north-east of Darwin in the Northern Territory. The Cobourg Peninsula Ramsar site boundary follows the former Gurig National Park boundary (now part of Garig Gunak Barlu National Park), and covers all wetlands of Cobourg Peninsula and nearby islands. This includes freshwater and extensive intertidal areas, but excludes subtidal areas. The peninsula is in a remote location and there has been minimal human impact on the site. The wetlands are mostly tidal and numerous creeks flow into the tidal areas. The northern coastline of the Peninsula has isolated bays, rocky headlands and beaches. The intertidal and coastal areas consist of extensive dunes, fringing coral and rocky reefs, sand and mudflats, with few areas of mangroves and seagrass communities. In contrast, the southern coastline and islands are dominated by mangrove communities associated with large mudflats. The main vegetation communities on the Peninsula are eucalypt forests and woodlands with grass understorey. There is also an unusually extensive area of tall palm on the Peninsula. An abundance of fauna use the wetlands including a large variety of birds, frogs, marine turtles, mammals and reptiles including the saltwater crocodile. The dugong lives in the marine area surrounding the Peninsula. The Ramsar site has significant social and cultural values, including archaeological material relating to its Indigenous, Maccassan and European heritage. These include occupation sites, traditional art, middens and waste heaps, abandoned settlements and houses, and shipwrecks. An on-going ‘living culture’ is maintained by the Arrarrkbi (traditional Indigenous owners of the Cobourg Peninsula) who uphold traditional land management practices, customary law and traditions. The Garig Gunak Barlu National Park is managed under a joint arrangement between the traditional owners and the Northern Territory Government. The Park is managed as a conservation reserve and is used for conservation, regulated tourism, hunting and Indigenous use. The waters surrounding the Peninsula support commercial and recreational fisheries.

Government evidence of impact of climate change:

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  • Australian Government, Cobourg Peninsula Ramsar Site, Ecological Character Description

    Of these threats; future impacts from climate change in terms of coral bleaching and saltwater intrusion and impacts from large populations of non indigenous ungulates (that is; pigs; banteng; buffalo and horses) and spread of cane toads are seen as the most likely and potentially severe.
    This period is based upon the frequency of large scale climatic phenomena that impact the site; such as ENSO events which occur over an approximate twenty year cycle (see Section; and is therefore ecologically meaningful in climatic processes impacting upon the site.
    Short to long term Medium Climate change coral bleaching Alteration to; or mass mortality of; coral reef communities due to increased incidence and intensity of coral bleaching events.
    Medium to long term Medium to high Climate change Increased saltwater intrusion from sea level rise Reduction in extent of freshwater wetland areas associated loss of species diversity and habitat and associated ecological and cultural values associated with these areas.
    Medium to long term Medium to high Climate change Changes to mangrove distribution from sea level rise Medium to long term Increase in mangrove extent at the expense of saltpan and Melaleuca communities possible loss of existing mangrove communities in foreshore and lower estuary zones due to increased sea level rise and water logging associated loss of species diversity and habitat and associated ecological and cultural values associated with these areas.
    Medium to high Climate change Changes to fire regime Changes to rates of evaporation and increased drought conditions leading to change in wetland inundation regimes and increased risks of wetland damage from more intense fires.
    Medium to long term Medium to high Climate change high intensity storms and cyclones Increase in damage to vegetation and habitats through more frequent events of extreme wind speed.
    The principal threats to the wetland values of the Cobourg Peninsula Ramsar site from climate change can be summarised as follows . increased incidence of coral bleaching due to rising sea temperatures . increased rate and extent of saltwater inundation into freshwater coastal environments due to sea level rise and increased frequency and or magnitude of storm surge events . changes in intertidal vegetation communities in response to rising sea levels . changed fire regimes resulting from hotter dry seasons; and subsequent damage to monsoon forest and coastal grasslands . increase in number of high intensity storms and cyclones and the resulting damage to vegetation and susceptible species. 5.3.1 Coral Bleaching The coral communities of Cobourg Peninsula live on the extreme edge of water temperature and turbidity limits for coral growth (Gomelyuk 2007).
    Whilst this appears to have been a natural incident; current climate change predictions are that the frequency of such events will increase.
    Climate change impacts include an increased risk of saltwater intrusion from sea level rise on low lying coastal wetlands.
    However; individual storm surge events; although infrequent; will continue to give higher extreme water levels overall (in the order of many metres) than sea level rise induced by climate change. 5.3.3 Mangrove Expansion As outlined in Section 3.4.1; the southern coastline of Cobourg Peninsula is dominated by extensive mangrove forests and saltpans.
    While Harper et al. (2008) concluded that there is no prima facie evidence of a climate change induced trend in tropical cyclone intensity in northwestern Australia over the last 30 years; an increase in high intensity storms and cyclones has significant potential to threaten the values of Cobourg Peninsula (Figure 5 2).
    The Indian Ocean Dipole is another long term climate phenomenon associated with warming and cooling phases in the Indian Ocean.
    As such; fire can have significant impacts on the landscape and is important for maintaining species and habitat diversity (Russell Smith 1995a).
    Fire regimes have been modified since the arrival of Europeans; and occurrences of intense late dry season fires are thought to have increased (Andersen et al. 1998 Vigilante and Bowman 2004).
    Scale Filepath CRITICAL COMPONENTS; PROCESSES AND SERVICES BENEFITS The existence of fire in the area; however erratic; still effects major changes in the viability and biodiversity due to the long history of traditional owner mosaic burning.
    The lack of a strict fire regime until recently has caused an increase in grassland and a decrease in shrubs; decreasing native fauna habitat suitability while increasing feeding opportunities for feral animals (Woinarski and Baker 2002).
    Exotic Flora Many parts of the northern Australia have infestations of non native plants that impact on the vegetation structure; fire regimes and ecosystem functioning.
    Weed species can significantly change the volume of fuel in the understorey and due to their ability to retain moisture longer than native species they do not burn until much later in the dry season.
    The fire regime on Cobourg Peninsula has changed since European colonisation; with the traditional Arrarrkbi burning regime of frequent; fine scale mosaic burns being replaced with less regular; more destructive fires.
    It is generally accepted that increased frequencies and intensities of fire associated with higher temperatures and longer dry seasons will threaten the values of Cobourg Peninsula.
    The understorey varies depending upon soils; landscape position and fire frequency; though annual and perennial Sorghum grass; Cycas spp.; Terminalia spp. and Acacia spp. are common elements.
    With wetlands on Cobourg Peninsula experiencing occasional extreme weather events; it is expected that these systems and the flora and fauna occurring within them; are in a state of flux.