Evaluación del desempeño

The Australian continent has been isolated from other landmasses for millions of years. The tropical marine fauna and flora have mixed with those of the Indo-Pacific since 10-15 million years ago, when the tectonic plates collided (Butler et al. 2010). The southern temperate regions of Australia, however, have remained isolated for over 65 million years (Poore 1995). Biogeographical, ecological and evolutionary factors have allowed the development of a unique ensemble of species (Phillips 2001) in what Bennett et al. (2015), called the “Great Southern

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Reef”. Considering only faunal species, the South-Eastern Marine Domain is the third most speciose of Australia, after the East-Central and North-Eastern Domains (Butler et al. 2010). Moreover, levels of endemism are much higher for the southern regions, possibly reaching 90% (IMCRA 1998; Butler et al. 2010). Certain taxonomic groups are more diverse in the southern regions of Australia, including macroalgae (Womersley 1990; Phillips 2001; Poloczanska et al.

2012), Porifera and Annelida (Butler et al. 2010).

Tasmania is part of the Southeast Australian Shelf Marine Province (Spalding et al. 2007). The Integrated Marine and Coastal Regionalisation for Australia (IMCRA 1998) identified eight mesoscale bioregions around Tasmania: Boags, Central Bass Strait, Otway, Franklin, Davey, Bruny, Freycinet, Flinders and Twofold shelf bioregions (Figure 4.4). Additionally, Tasmania has jurisdiction over the coastal waters around sub-Antarctic Macquarie Island. The Macquarie

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Figure 4.5 Meso-scale Bioregions in Tasmanian waters

Source: (Resources Planning and Development Commission 2003b)

The diversity of Tasmanian marine bioregions is influenced by the interplay between climate, oceanography, bathymetry and biogeography (Parsons 2011). Average sea-surface temperatures are typically 10-12⁰C in winter and 15-20⁰C in summer, although differences of more than 4⁰C have been reported across the State (Harris et al. 1987). These temperatures, however, are variable depending on seasonal events, freshwater input, geographic features and most importantly, oceanographic currents. The major currents that influence the island are the Eastern Australian Current, the Zeehan Current and the Antarctic Circumpolar Current. The latter is a cold nutrient-rich current that moves mainly eastward (Department of Primary Industries Water

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and Environment 2000). The Zeehan Current is the last section of the 5,500-km Leewin Current. The Leewin Current flows southward along the western coast of Australia, then eastward along the southern coast of Australia, to finally flow southward along the West coast of Tasmania (Ridgway and Condie 2004)–. The East Australian Current is the major current flowing southward along the east coast of Australia. It has a seasonal variation, having a stronger influence in Tasmania during summer (Ridgway and Godfrey 1997). The latter two currents bring warm nutrient-poor waters. In general, the west coast of Tasmania is a high-energy coastline, with significant swells.

The east coast has much lower wave energy, being affected by the predominant southwest winds and low-pressure fronts (Department of Primary Industries Water and Environment 2000). The east coast, however, has a more convoluted coastline, which determines the presence of several estuaries and inlets (Edgar et al. 2000). Estuaries are a key habitat, due to their role as nursery and feeding areas for commercial and non-commercial species (Resources Planning and Development Commission 2003b). The central Bass Strait has the lowest wave-energy, as it is protected from predominant swells and because shallower waters allow the dissipation of wave energy (Department of Primary Industries Water and Environment 2000). This variety of conditions determines that major marine biomes can be distinguished between the Bass Strait, the north, east and western coasts (Edgar et al. 1993; Department of Primary Industries Water and Environment 2000). The SEAMAP project mapped a large extent of Tasmanian habitats using a combination of methods, including acoustic surveys, remote sensing and video (Institute for Marine and Antarctic Studies 2011). The main habitat types identified are rocky reef (high, medium or low profile), unvegetated unconsolidated substrate (gravel, sand, silt, cobble) and vegetated unconsolidated substrate (seagrasses, algal beds, aquatic macrophytes). Parsons (2011) provides a good overview of the marine biodiversity of Tasmania, including species, habitat types and sites with particularly high conservation value. Table 4.11 describes the main characteristics of Tasmanian bioregions.

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Table 4.11 Characteristics of Bioregions around Tasmania

Province/

Biotone Bioregion Characteristics

Mean number of species (fish, invertebrates and plants) Ta sm a n ia n Pro v in ce

Franklin Extremely exposed, open coastline, long sandy beaches and rocky headlands. High energy and dark estuary waters may explain its low diversity. Low anthropogenic impact. Important for birds. High value sites include Macquarie Harbour, one of the largest estuarine systems in Australia with a highly stratified water column and habitat to the endangered Maugean skate (Zearaja maugeana). Other sites include the Sloop Rocks and the unique Wanderer estuary.

Tidal range: 1.5 m.

Habitats: seagrass (0%), sand (61.9%), reef (38%).

27.1

Davey Extremely exposed coastline, rocky headlands, sandy beaches, with a strong influence of the Southern Ocean. Pristine conditions. In high-energy areas, bull kelp is found much deeper than is usual. Port Davey/Bathurst Harbour is one of the high value sites, recognised as World Heritage. Unique conditions, with a shallow entrance, a deep channel and a significantly isolated harbour. High stratification, with a tannin layer at the surface and a clear salt-water layer at the bottom. Typical deep-water species are found here in shallow waters. High endemism and unique invertebrate communities. Other high value sites include Maatsuyker and Pedra Branca Islands, key areas for birds and seals, including endangered elephant seals (Mirounga leonine) and shy albatross (Thalassarche cauta).

Tidal range: 1 m.

Habitats: seagrass (2.5%), sand (49.8%), reef (47.8%).

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Bruny Dissected coastline with large numbers of protected bays, headlands, estuaries and cliffs. Exposure is therefore variable. Mostly influenced by nutrient-rich subantarctic waters. Two large drowned-river estuaries (Huon and Derwent) have an effect on sediments, salinity and nutrient levels. Presence of cold-water species not found further north, and high species richness and endemism, including endangered species such as the live-bearing seastar (Parvulastra vivipara) and handfish species (Brachionichthyidae). High value sites include the Huon estuary entrance, where a tannin layer combined with high nutrients from the Southern Ocean result in a unique ensemble of species. Other high value sites include Bruny Island headlands; Pittwater/Orielton Lagoon as a key saltmarsh and shark nursery area; Tasman Peninsula, with outstanding cliffs and caves and high diversity, including deep-water species like the Southern Bluefin Tuna (Thunnus maccoyii) and Albacore (Thunnus alalunga), as well as kelp forests (Macrocystis pyrifera).

Tidal range: 1 m.

Habitats: seagrass (3%), sand (82.7%), reef (14.3%).

48.4

Freycinet Relatively exposed, with rocky headlands, beaches and lagoons. Species communities vary along the coast according to the level of influence of the East Australian Current. The northernmost kelp forest in the Southern Hemisphere is found here. Lagoons and estuaries are important habitat for birds. High value sites include Schouten Island; Ile the Phoques with a unique cave system; the Georges Bay native oyster reef; Maria Island with the highest diversity of reef plants and animals in Tasmania; and Governor Island.

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Province/

Biotone Bioregion Characteristics

Mean number of species (fish, invertebrates and plants) Tidal range: 1.5 m.

Habitats: seagrass (3.3%), sand (78.4%), reef (18.3%).

Ba ss ia n Pr o v in ce

Boags Sheltered open coastline, long sandy beaches and rocky headlands. Shallow areas and strong tidal currents. Important marine and shorebird habitats. Extensive seagrass beds, including the southernmost distribution of warm temperate species. High diversity, including Bass Strait species rare in southern bioregions. Rocky cape, the Tamar estuary and Waterhouse are considered high value sites.

Tidal range: 3 m.

Habitats: seagrass (11.4%), sand (75.3%), reef (13.3%).

48.6

Flinders Rocky coastline with sandy beaches on shallow areas. Exposed on the east of Flinders Island, moderate to low exposure elsewhere. Large number of estuaries with high conservation value and extensive seagrass beds. Important bird habitats and key breeding area for the Australian Fur Seal. Species not present in other regions. High value areas include the North East Inlet and the west coast Furneaux seagrass beds, Judgement Rocks, and Franklin Sound.

Tidal range: 3 m.

Habitats: seagrass (10.5%), sand (82.5%), reef (7%).

42.9

Twofold Shelf Relatively exposed with long sandy beaches, rocky headlands and lagoons. Sea surface temperature influenced by East Australian Current. The Kent Group is considered a high value site, as the convergence of three provinces, diversity of habitats and good water quality support a high biodiversity, with many species not found in southern bioregions. This includes an unusual coral community.

Tidal range: 2 m. Habitats not mapped.

51.4 We st Ba ss ia n Bi o to n e

Otway Exposed, steep coastline. Strong currents associated to the entrance to Bass Strait. Connected to South Australia and Victoria through the Leeuwin current, sharing some marine biota. Important for high-energy and oceanic species. High value sites include King Island, with diversity of marine habitats and bird breeding areas; and the Seabird Islands with their colonies of shy albatross and other birds, as well as Otariids.

Tidal range: 0.6 m on the West coast and 1.2 m on the East coast.

Habitats not mapped.

44.8 Ma cq u a rie Is la n d Pro v in ce

NA It comprises waters surrounding Macquarie Island and seamounts. The biota is a mixture of Antarctic and cool temperate elements. Important for endangered marine birds (albatross and penguins) and mammals. Along with the Commonwealth Macquarie Island Marine Park, it has been included in the World Heritage List.

Tidal range: 1m Habitats not mapped.

NA

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There are several implications on MPA governance of a natural context characterised by high diversity, high endemism and rapidly changing conditions. For example, when species have small or patchy distributions, conservation actions need to include local actors, be specific in location and address threats particular to those species. On the other hand, as will be detailed in the next section, certain threats span over great expanses of the oceans. In this case, good coordination across all governance levels, from the local, State and regional, is fundamental to managing marine resources. The need to have good coordination across levels is not limited to governance regimes, but also for monitoring and sharing of information. Changing conditions, accelerated by climate change, require a governance regime that is prepared to deal with those changes (Lockwood et al. 2012).