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Issues ConditionThreatening Processes |
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At a glance 
The issue Geodiversity is the natural diversity of geological, landform and soil features, and processes. Geoconservation is 'the conservation of geodiversity for its intrinsic, ecological and (geo)heritage values' (Eberhard 1997). Geoconservation is complementary to biological conservation ('bioconservation') in that it seeks to conserve the non-living aspects of the natural environment, as an integral part of a balanced approach to nature conservation. The geoconservation values of significant phenomena can be degraded by human-activities that either change the significant and valuable features of a site, or that change the natural processes controlling the continuing development of the feature. This 'At a glance' section provides an overview of the issue of geodiversity and geoconservation. More detailed information and references are available in the Geodiversity and Geoconservation Issue Report. Three types of indicators are included in the Issue Report: data coverage, site integrity and process integrity, with emphasis placed on the latter two. These are described in the Assessing and measuring the current situation section and presented in the Indicators section of the report. A recommendation is also provided on Geoheritage Values. Favourable news - The Tasmanian Geoconservation Database (TGD) for sites of geoconservation significance was initiated in 1996 and is subject to ongoing review and upgrading by an expert reference group. The TGD is held by the Department of Primary Industries, Water and Environment (DPIWE).
- An assessment of the sites on the TGD (version 3, 2001) found that of the 833 listed geological sites of geoconservation significance, 21.2% have experienced no degradation and 23.8% are secure. However, the condition and conservation status of a significant proportion of the geological sites are unknown (see Uncertain news).
- Of the 762 geomorphological sites of geoconservation significance listed on the TGD, 32.3% have experienced no degradation, 26.5% are secure, and none have been recorded as destroyed. However, the condition and conservation status of a significant proportion of geomorphological sites are unknown (see Uncertain news).
- Of the 69 soil sites of geoconservation significance listed on the TGD, 26.1% have experienced no degradation, 29% are secure, and none have been recorded as destroyed. However, the condition and conservation status of a significant proportion of the soil sites are unknown (see Uncertain news).
- A conservation, management and extension strategy for fluvial systems in Tasmania has been developed by DPIWE (Jerie et al. 2003). The project classifies Tasmanian fluvial landform systems into distinctive 'fluvial georegions'. The regionalisation will provide a classification of fluvial geodiversity at a regional/State level and assist in improving geodiversity condition indicators.
- Based on the Planning and Management Catchments of Tasmania (as an interim classification of fluvial systems) it has been found that the natural fluvial geomorphic systems that have been least affected in terms of vegetation clearance, land cover modification and road density (less than 2 m/ha) occurred within the Gordon-Franklin, Port Davey and Wanderer-Giblin catchments in the south-west and west of the State. The Gordon-Franklin and Port Davey catchments also have the greatest amount of their areas protected against land cover change (84.7% and 98.7% respectively).
- Mapping of geodiversity has improved through the update of the Tasmanian Karst Atlas (Kiernan 1995) - version 2 (Forestry Tasmania 2002, held by Forestry Tasmania) and with the development of the Tasmanian Coastal Geomorphic Types database (Sharples 2000 and 2002 - held by DPIWE). These will assist with the ongoing development and improvement of geodiversity condition indicators.
- An assessment of the Karst Atlas v.2 found that the natural karst geomorphic system (based on simplified lithological karst types) that has been the least affected by land cover modification and high road density, is the Silurian-Devonian limestone (less than 7% land modified of 30,742 ha total area; with <2 m/ha road density). The Silurian-Devonian limestone type has the greatest proportion of its area protected against land cover change (47%), closely followed by the Precambrian-Cambrian dolomites (30%).
- Based on a coastal georegion classification, which forms part of the Tasmanian Shoreline Geomorphic Types database, it has been found that 92 of the 132 distinctive coastal georegions have no substantial artificially modified shorelines.
- The Tasmanian Wilderness World Heritage Areas geoconservation values have recently been reviewed and a number of new values have been identified.
- Many detailed site-specific management initiatives have occurred and these are outlined in the Management Responses section in the Issue Report. Examples include: the purchase of a number of karst areas around Mole Creek for the protection of geoconservation and other values; revegetation work has been conducted on a number of streamsides in the Mole Creek area to assist in the protection of karst values; and rehabilitation of the Ida Bay Quarry continues with further improvements in physical and biological environments in the nearby Exit Cave system.
- The high erosion rates on the previously destabilised banks of the Gordon River continue to decline.
- Land cover and vegetation management responses have a key role in protecting geodiversity processes. Initiatives include: vegetation mapping through TASVEG; an enhanced comprehensive, adequate and representative forest reserve system; and the Protected Areas on Private Land Program, which provides management assistance and a range of incentives to landowners who enter into formal conservation agreements.
Unfavourable news - Of the 833 geological sites of geoconservation significance listed on the TGD, 9.7% have undergone some level of degradation, 24.2% are either endangered, threatened or have a potential threat, and 0.4% have been destroyed. However, the condition and conservation status of a significant proportion of the geological sites are unknown (see Uncertain news).
- Of the 762 geomorphological sites of geoconservation significance on the TGD, 20% have undergone some level of degradation, and 27.6% are either endangered, threatened or have a potential threat. However, the condition and conservation status of a significant proportion of the geomorphological sites are unknown (see Uncertain news).
- Of the 69 soil sites of geoconservation significance on the TGD, 31.9% have undergone some level of degradation and 43.4% are either endangered, threatened or have a potential threat. However, the condition and conservation status of a significant proportion of the soil sites are unknown (see Uncertain news).
- Natural fluvial geomorphic systems in Tasmania have been, or are likely to have been, impacted or modified by human activities (e.g. vegetation clearance, land cover modification and road density). In particular, this has occurred in many of the catchments along the north-west coast (e.g. the Cam, Inglis, Blythe, Rubicon, Leven, Montagu, King Island, Emu) and in the Midlands. Other catchments have been specifically affected by high urban and suburban land modification and road densities greater than 20 m/ha. They include: the Derwent Estuary-Bruny, Tamar Estuary (by both impact types), the Lower Derwent and North Esk (by land modification), and the Little Forester (by road density greater than 20 m/ha). The catchments that have the least amount of their areas protected against land cover change (greater than 75% of their area) are also those predominantly in the north-west and Midlands areas.
- A recent development in the Picton Valley has impacted on a Pleistocene fluvio-glacial landform in the valley.
- The natural karst geomorphic systems (based on simplified lithological karst types) in Tasmania that have been-or are likely to have been-impacted or modified by human activities (e.g. landcover modification and road density) include the Tertiary marine limestones (70% of 15,071 ha; and road density of 8 m/ha), Quaternary limestones (34.8% of 28,995 ha ; road density of 15.4 m/ha), Permian limestones (33.1% of 21,635 ha; and road density of 17.7 m/ha), and the Ordovician limestones (24.5% of 135,391 ha; and road density of 8.1 m/ha). The Tertiary marine limestones, Quaternary limestones, and Permian limestones, also have the least amount of protection from land cover change in more than 50% of their area (91%, 91%, and 79%, respectively).
with the least amount of protection in more than 50% of their area include- Of the total Tasmanian coastline length of 6,438.6 km (at 1:25,000 scale and including most islands but excluding most small islets and rocks), 143.5 km (2.2%) is identified as wholly or substantially artificial. Of the 132 distinctive coastal georegions around the Tasmanian coast, 40 have some degree of artificial coastline.
- Coastal (wave) erosion is continuing to impact extensively on sandy coastal landforms around the State.
Uncertain news - The condition (degradation) of a large percentage of the sites listed on the TGD have yet to be determined and classified: 68.9% of the 833 geological sites, 47.8% of the 762 geomorphological sites, and 42% of the 69 soil sites. The conservation status of a significant percentage of the sites listed on the TGD was also unknown: 51.8% of the geological sites, 45.8% of the geomorphological sites, and 27.5% of the soil sites.
- Because the fluvial geomorphic classification of rivers in Tasmania (Jerie et al. 2001) was not available at the time of this SoE Report, a catchment classification was applied as a basis for measuring fluvial process integrity indicators. This classification is primarily topographic rather than based on fluvial geomorphic criteria, and as a result, only a more generalised assessment of the state of fluvial processes within given geographical regions could be provided.
- Tasmanian karst georegions have yet to be finalised to improve indicators of karst process integrity.
- There is limited soil mapping coverage of the State, restricting the ability to determine the full diversity of Tasmanian soil systems, and how well that diversity is being conserved.
- There has been no Statewide mapping of peat erosion. Peat erosion between Elliot Bay and Birches Inlet was reported in the previous SoE Report and an update of this will be available in the future.
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