Geodiversity is the natural range (diversity) of geological (rocks, minerals, fossils), geomorphological (landform and processes) and pedological (soil) features (Internal linkGray 2005; Internal linkEberhard 1997). It includes their range of assemblages, relationships, properties, interpretations and systems and is an essential foundation for soil health and biodiversity. For example, a tiny islet or rocky outcrop found 26 km off the south-east coast of Tasmania in the Tasman Sea called Pedra Branca Rock, is the only place in the world where the endangered Pedra Branca skink (Niveoscincus palfreymani) lives. Without this geological landform the skink would not exist (Internal linkPWS 2008). In addition, knowing more about our geodiversity helps us to interpret change processes in the landscape such as fluvial and coastal erosion. Geodiversity also has an intrinsic value and it plays a vital role in the community's sense of place, belonging, history and well-being. A number of people value highly the aesthetic and intrinsic values of geological features.
Many of the landscapes that make up Tasmania's geodiversity are a result of the underlying ancient rock structures of very old Paleozoic rocks (524–300 mya) to the west and old Mesozoic rocks (300–140 mya) to the east of the State. They are also the result of modifications of the older Paleozoic and Mesozoic topography by Tertiary block faulting (that began about 65 mya). The distribution of these ancient rock formations are shown below in Map A. Fluvial processes shaped the land surface during the Tertiary era etching out geological structures, including faults and dolerite sills in eastern and central Tasmania, while fold structures and granite bodies in western Tasmania were exposed after flat-lying sediments and dolerite sills were removed by erosion. Some overlying structures, now long gone, are still reflected in western rivers that flow east-west across the grain of the now exposed folded basement rocks. Basaltic lava flows modified Tertiary drainage patterns, giving rise to the precursors of the modern drainage system. The Tertiary landforms were rapidly modified by energetic glacial, periglacial and glacio-fluvial processes during the last few million years, but are today being only slowly modified by ongoing fluvial processes. Glacial and periglacial landforms in Tasmania are relict (fossil) features produced by processes that are no longer active (the most recent glaciation probably began some 25 tya and reached its peak at roughly 19 tya). Glaciated landforms in the State are shown in Map B. Inland aeolian features in eastern Tasmania that have been deposited or eroded by the wind from the last glacial age are also commonly found inland as deflation hollows and associated lunettes. These landforms are shown in Map C. Collectively, these ancient landforms form a foundation for Tasmania's geodiversity and they cannot be regenerated if damaged.
Geodiversity is an important part of the State's natural heritage. The term first appeared in articles from Tasmania in the mid-1990s and has now become accepted internationally by many environmental agencies and organisations (Internal linkSharples 1993; Internal linkDixon 1995; Internal linkKiernan 1996). Examples of geodiversity in Tasmania include the following landforms.
There are many geomorphological features in Tasmania that have been formed by aeolian processes. Relict features that have been mapped are commonly found inland such as the lunettes at Moulting Lagoon on the east coast, Double Lagoon on the Central Plateau, Woodstock Lagoon near Longford and the Ellinthorp lunette cluster between Lake Sorell and Ross. Other aeolian features located to the west and south of the State have yet to be mapped. There are also active coastal dune systems (often parabolic) that overlie predominantly linear dunefields of late Pleistocene era (about 10,000 years ago) such as the Henty Dunes near Strahan, the Anderson Bay Waterhouse dunefield, and transgressive sand sheets at Interview River.
Aeolian landforms are highly erodable and vulnerable to changes in the environment. For example, some relict aeolian features have been partially re-activated by recent land degradation. Wind erosion is particularly prevalent in dry environments including coastal areas, the midlands, and areas of poor vegetation cover and inappropriate land use. Despite lying in the path of the 'Roaring Forties' and having higher average wind speeds than the mainland states, Tasmania has not been overly susceptible to wind erosion (Internal linkDPIPWE 2009). However, significant degradation of the land resulting from wind erosion is difficult to detect. It is predicted that climate change will lead to windier and drier conditions, and, when coupled with more intense equinoctial wind events, may increase erosion of aeolian landforms and other geodiversity. More information on wind erosion is provided in the embedded document Internal linkWind Erosion in Tasmania.
Bays, lagoons and boulder and sand beaches that are found around Tasmania's coastline, as well as Australia's highest sea-cliffs found on the hard rock coasts of the Tasman Peninsula. There are also low energy systems with extensive tidal flats such as the symmetrical spits and tidal inlet at Stanley.
Coastal landforms can be more or less resilient to environmental and climatic change. However, these highly exposed environments are generally vulnerable to sea-level rise, coastal inundation and/or the drying of estuarine areas prone to reduced freshwater runoff. For example, scientists are observing changes in some coastal landforms such as coastal recession and the exposure of peat layers to beach cliff forms at Ocean Beach on Tasmania's west coast. Coastal recession processes at Ocean Beach are illustrated in the following diagram.
Coastal recession processes
Coastal recession processesinternal SOE link to larger image
Spectacular erosional landforms have developed in Tasmania as a result of late Cenozoic glaciation (about 2 mya –10 tya) on multiple occasions. For example, we have distinctive mountain landforms that have developed on columnar dolerite substrates at Cradle Mountain. In addition, ice cap glaciation of massive dolerite sills has left a profusion of shallow tarns across the Central Plateau. Moraines are also found in lowland settings in the centre and west of the State such as those found at Federation Peak.
These landforms, along with periglacial landforms, are generally well reserved in Tasmania and are also comparatively resilient to environmental and climatic change in human time scales.
Many highland landforms have been shaped by periglacial freeze-thaw conditions. Extensive relict blockstreams encircle the higher dolerite peaks of central and north-east Tasmania such as those found at Western Bluff on the Great Western Tiers. There are also active periglacial systems found on the higher peaks in Tasmania such as at Nevada Peak and frost hollows that occur in plateau areas including Lake Augusta.
Western Tasmania has been one of Australia's most active neotectonic regions, with late Cenozoic uplift rates in the order of 100 m/million years. We have spectacular flights of marine fluvial terraces such as those found at Birches Inlet. We also have Pleistocene fault scarps (from about 1.8 mya –10 tya) that are tens of metres high in the south-west such as the unnamed scarp on the D'Aguilar Range and the fault line at Lake Edgar.
Uplift and erosional landforms are also found on Tasmania's offshore islands. For example, Macquarie Island has been formed by marine erosion processes such as wave erosion as it has risen above sea-level. The island has been squeezed upwards from the oceanic crust and evolved in the Oligocene–Miocene era (between 30–11 mya) as a spreading ridge (Internal linkPWS 2008). It is the only known example of oceanic crust being uplifted as a result of transpression at an ocean-ocean plate boundary. This geological process has resulted in the rocks being far less deformed than similar rocks on other islands and elsewhere. Macquarie Island also has a series of raised beaches or areas eroded by waves at altitudes ranging from 6–400 m that emerged above sea-level approximately 600–700 tya. In addition, earthquakes and extensive faulting have triggered landslip events and shaped the coast, created fault dammed lakes and controlled the location of major landforms. On the basis of its outstanding geomorphic features, Macquarie Island was inscribed on the World Heritage List in 1997 (see Internal linkDEWHA 2008).
Evolving fluvial landforms
Fluvial landforms and rivers take many different forms and they are related to strong east-west climatic gradients, topographic variety and diverse geology. There are spectacular superimposed gorges such as those found on the Franklin River and broad, deep estuaries are found in their lower reaches such as those on the Gordon River. Sinuously meandering gravel bed streams also wind across Tertiary conglomerates (formed between 65–1.8 mya) such as the Sorell River that meanders south of Macquarie Harbour. In addition, distinctive 'broadwater' sequences, with repeating pool, fan/splay and meandering reaches have developed in deep, dispersive silts and clays in the midlands such as those found on the South Esk River. The geomorphology of fluvial landforms link changes in hydrology with changes in catchment sediment budgets.
Fluvial landforms are comparatively more susceptible to environmental and climatic change and human disturbances. These landforms have been increasingly affected in recent times because drought conditions have resulted in reduced streamflows and increasing pressure by water users on water resources. In addition, there have been more episodic rainfall events that potentially increase surface runoff and erosion. Splash erosion or rain drop impact represents the first stage in the fluvial erosion process. More information on water erosion processes, including streambank erosion, is provided in the embedded document Internal linkWater Erosion in Tasmania.
Karst landscapes have distinctive landforms and drainage characteristics resulting from the relatively high solubility of certain rock types, notably limestones and dolomites, in natural waters where erosion has produced fissures, sinkholes, underground streams and caverns. They are commonly regarded as special and spectacular, and worthy of conservation. They also provide specialised habitats for a variety of organisms and they contain aquifers. The dependence of karst processes on natural water flows means that karst is highly sensitive to drying in the climate and human activities that alter natural water chemistry, sediment content and flow regimes.
Tasmania's karst is diverse and spectacular. Mountain karst systems include the Vanishing Falls in the south-west and the Annakananda doline on the Mt Anne north-east ridge. Coastal karst in aeolian calcarenite is common on Bass Strait islands, such as the tufa terraces found at Boggy Creek on King Island. The State also has many spectacular karst cave systems including one of Australia's best decorated caves — the Kubla Khan cave system at Mole Creek. This cave has many chambers and stream passages and is decorated with large columns, forests of stalactites and stalagmites and rimstone dams more than 2 m high (Internal linkHamilton-Smith and Finlayson 2003). Other significant cave systems include Gunns Plains Cave; Khazad-Dum in Mount Field National Park (one of the deepest potholes in Australia); those found in the Mole Creek Karst National Park; and others in the south of the State such as Exit Cave (the longest known cave in Australia), Midnight Hole (a 162 m vertical cave that forms part of Mystery Creek Cave) and Newdegate Cave (including a thermal pool at Hastings) (see Internal linkPWS 2006).
Karst often drains through natural subterranean conduits, some of which become caves that are large enough for humans to enter. These complex surface and subsurface drainage and landform types are known as karst systems. Geological structures rather than surface contours are likely to control directions of flow in karst, and there are many examples in Tasmania of major topographic drainage divides being breached by subsurface karst streams. As a consequence, specialised techniques (including water tracing) are often required to map flow directions and catchment boundaries in karst.
Karst systems are highly susceptible to changes in upstream catchments and altered water balances. However, any changes, such as declining streamflow from the catchments, can take time before they are expressed in karst formation. Lags in the expression of ecosystem changes can result in karst systems appearing to be more resilient and having inherent buffers to altered environmental conditions. Delayed cumulative impacts to karst systems have the potential to be significant and long-lasting. Given their environmental sensitivity, karst systems can provide an indication about the condition of the catchments they depend upon.
Although landforms and geological features are commonly thought to be robust, many aspects of geodiversity such as cave systems, sand dunes, river features, moraines, soils and fossil sites are highly susceptible to damage. More information on geodiversity can be found though the Department of Primary Industries, Parks, Water and Environment (DPIPWE) External linkGeoconservation website.
Geoconservation is 'the conservation of geodiversity for its intrinsic, ecological and (geo)heritage values' (Internal linkEberhard 1997). It is complementary to bioconservation in that it seeks to conserve the natural non-living aspects of the natural environment, as an integral part of a balanced approach to nature conservation. Geoconservation focuses not only on conserving bedrock geological features, but also landforms (geomorphology) and the natural integrity of active geomorphic processes such as karst, fluvial and coastal systems (Internal linkHoushold and Sharples 2008; Internal linkPemberton 2007; Internal linkSharples 2001). Using the terms 'geodiversity', 'soil diversity' and 'biodiversity' helps to indicate that our natural environment consists of living and non-living components (see also Internal linkGray 2005). When taken together, these components can help to promote a more holistic approach to nature conservation than the traditional biocentric focus. Moreover, geoheritage refers to those specific features, landforms, soils or systems of geoconservation value that is of value in its own right or as part of a natural process. Geoheritage places are natural features we value and seek to conserve.
In respect of geoconservation and geodiversity, the most important natural process systems active in Tasmania today are fluvial (running water), karst, coastal (including coastal aeolian) and soil processes. Inland aeolian and periglacial processes are currently minor in the Statewide context, and occur in localised areas. These key processes are fundamental in the formation, maintenance, and development of Tasmania's geodiversity.
The geoconservation values can be degraded by human activities that either change the significant and valuable features of a site, or change the natural processes controlling the continuing development of the feature. Landforms composed of unconsolidated sediments are particularly vulnerable (Internal linkKiernan 2007). Geological and landform features are typically fossil or develop so slowly that degradation is permanent and destruction, or extinction, of an important site can occur from a single event such as excavation or the passing of one bulldozer blade, the removal of specimens or poor land management practices. For instance, many important geological and landform features are of small scale and may easily be destroyed by land development or resource extraction activities. Other landform systems such as karst and fluvial systems are dependent on balanced physical and chemical conditions and they can be significantly damaged if changes occur in their surrounding environment.
Some examples of geological and landform features in Tasmania that have been lost or damaged include the following:
It is impossible to produce a comprehensive list of all the potential pressures and threats to geoconservation values. Numerous human activities can impact on these values, and the variety of types and vulnerabilities of Earth phenomena means that an activity may have detrimental effects on some Earth features while others are robust and essentially impervious to the pressure. The embedded Internal linktable summarises some conservation concerns about significant Earth features and processes. These examples are illustrative and do not present an exhaustive list.
In addition, climate change and sea-level rise are likely to have major effects on geodiversity in Tasmania. However, the nature and intensity of these effects are poorly understood at present. A CSIRO and Bureau of Meteorology report predicts that by 2010–40, exceptionally hot years might affect about 75% of the State, and occur every 1.3 years on average; that by 2010–40, exceptionally low rainfall years might affect about 10% of the State and occur about once every 12 years on average; and by 2030, exceptionally low soil moisture years might affect about 11% of the State and occur about once every 9 years on average (see Internal linkHennessy et al. 2008). More information on climate change is provided in the embedded document Internal linkClimate Change in Tasmania. Additional information on climate variability, climate change and habitat change in Tasmania can be found in the Internal linkClimate Variability and Change (Air) Issue Report, Internal linkClimate Change and Natural Values (Natural Values) Issue Report and Internal linkHabitat Change Issue Report.
Geotourism is an area which has received little attention in Tasmania. In many parts of the world, geotourism is seen both as a way of making geoconservation 'pay for itself', as well as being a means of justifying expenditure on geoconservation initiatives (Internal linkSharples 2004). Much of the tourism in the State is classified as 'ecotourism' and based on promotion of our relatively undisturbed natural environment. For example, the natural landscapes of the Tasmanian Wilderness World Heritage Area (TWWHA) are one of the key drawcards for tourism. Ecotourism is a significant sector of the Tasmanian economy. In 1989, the International Union for the Conservation of Nature (IUCN) recognised the contribution of geodiversity values in the TWWHA to three of the four natural values criteria for nomination. Some sites recognised as being of outstanding universal value in the TWWHA include:
Geoconservation in Tasmania focuses on developing a comprehensive, adequate and representative (CAR) approach to the conservation and management of geodiversity. Land managers aim to target the best (or most outstanding) examples of natural geological, geomorphological and pedological features, assemblage of features, or processes and systems.
In the last five years since the 2003 SoE Report, the most significant improvements in the capacity to monitor and assess the condition of geodiversity in Tasmania have related to karst and fluvial process integrity. There has also been far greater attention to the coastal zone due to growing community concern about the importance of coastal geomorphology in coastal vulnerability to sea-level change. There are few dedicated programs directed towards monitoring changes in the condition of Tasmania's geodiversity, although programs such as the Conservation of Freshwater Ecosystem Values (CFEV), Tasmania River Condition Index (TRCI) and Monitoring Vegetation Extent Program (MVEP), along with fluvial systems and coastal geomorphic mapping can help to inform an assessment of some components of geoconservation condition.
Geoconservation focuses on identifying and classifying the range of geological, geomorphic and soil phenomena. Indicators in this SoE Report provide measures of our knowledge about the different elements of geodiversity in Tasmania. The following three broad categories of geoconservation indicators that were proposed in the previous SoE reports remain relevant (Internal linkSharples 2001). However, none of these indicators in this SoE Report provide a comprehensive assessment of geodiversity or the condition of geological features or geomorphological processes. There appears to be a continuing need to assess geo-programs that contribute to our understanding about geodiversity in terms of their capacity to inform geoconservation issues.
The most critical themes for geoconservation assessment and management in Tasmania have been assessed as fluvial, karst, coastal and soil issues. This is because they involve the maintenance of ongoing natural processes in the ecosystem and are pervasive natural values in the landscape. Fossil geoheritage features (e.g. bedrock features, relict landforms) are also locally important at the sites where significant features occur, but are less pervasive across the landscape.
Our ability to identify or locate representative (or outstanding) examples of each significant element of geodiversity depends on mapping and research on geological, geomorphic and soil features and systems. Our capacity to identify, assess and monitor representative examples of Tasmania's diverse geodiversity also governs our ability to know whether the State's geodiversity is being conserved and appropriately managed (and thus our ability to identify geoconservation issues and priorities requiring action). Relevant data coverages and their approximate data availability status are identified in the table below.
Data coverage of geoconservation mapping and inventories Source: DPIW 2008
Data coverage of geoconservation mapping and inventories
Source: DPIW 2008
Geological mapping and research in Tasmania has traditionally been biased toward areas considered likely to be prospective for economic mineral deposits (or problems of slope and stability in urban environments). This bias was more pronounced in the 1980s and 1990s with the coverage of geological mapping, particularly the 1:25,000 map series, reflecting the emphasis on mineral deposits. Areas of eastern and southern Tasmania that are perceived as relatively unprospective have only been mapped at a 1:250,000 reconnaissance scale.
The varying degree of geological mapping has consequences for geoconservation and geological heritage inventories, in that there is greater awareness of significant geological phenomena for the areas that have been mapped (and therefore studied) in more detail. The current status of geological mapping coverage of Tasmania is presented in the embedded Internal linktable.
Current soil mapping for Tasmania comprise reconnaissance soil maps that cover some of the agricultural areas and a few of the designated reserves. Much of the reconnaissance soil mapping was undertaken by CSIRO in the 1940–60s (originally published at 1:63,360 scale). These small- and large-scale soil survey maps and reports form the basis of our current knowledge and understanding of the distribution and types of soils (as a component of geodiversity) within the State. Soil maps have been developed using the CSIRO reconnaissance soil mapping as a base for the majority of agricultural areas in the State and they are covered by the updated reconnaissance 1:100,000 soil maps series. However, there remain many areas of Tasmania, including highly productive agricultural areas, where no soil maps exist. Overall, mapping of soils is best known in the more disturbed areas (i.e. agricultural land, private land, State Forest), and less well known in more undisturbed areas (i.e. national parks, reserves). More information on the updated reconnaissance soil maps series can be found though the Internal linkSoil Diversity Issue Report, Internal linkDistribution of Soils Indicator and the DPIPWE External linkSoil Maps of Tasmania website.
The TGD is the over-arching inventory for geodiversity in Tasmania. The database is maintained by DPIPWE. The purpose of the TGD is to record all sites and areas in the State that have been recognised as having significant geoconservation value by inventory processes. The TGD was initiated in 1996 during the Tasmania-National Regional Forest Agreement (RFA) process by amalgamating records from all Tasmanian reconnaissance-level inventories that were available (Internal linkDixon and Duhig 1996). At the time, the TGD was developed in a forestry context although it was recognised that the database had a wider application and DPIPWE assumed responsibility for its management in 1999 (Internal linkEberhard 2008).
Sites listed on the TGD v.6.0 (2008) occupy an area of 4,104,842 ha, of which 3,206,805 ha (78%) is reserved land. The database is subject to ongoing annual review and upgrading by an expert reference group comprising geoscientists from government, industry and the University of Tasmania. On the advice of the expert reference group, 48 new sites were listed, 19 sites delisted and improvements were made during the period 2003–07 (Rolan Eberhard pers. comm. 2009).
The TGD has no statutory basis, but is widely used as a planning tool by government and non-government agencies. The database is referred to in the State Codes of Practice: Mineral Exploration Code of Practice 1999, Reserve Management Code of Practice 2003 and Forest Practices Code 2000. In addition, some reserves established under Tasmanian Government programs such as the Community Forest Agreement (CFA), Private Forest Reserves Program (PFRP) and Protected Areas on Private Land (PAPL) have been selected with reference to geoconservation criteria. However, many other reserves established under these programs have not been selected with reference to geoconservation criteria. Geological, geomorphological and soil values have yet to be systematically assessed for these reserves.
One recent example of a site listed on the TGD is the Egg Islands near Huonville. Covering 440 ha, the two islands are listed in the TGD as a representative geomorphological feature (tidal delta islands) of State significance. They comprise a mix of marshlands, forests and wetlands that are partly privately owned and partly managed by the Parks and Wildlife Service (PWS) as a conservation area. The Tasmanian Land Conservancy (TLC) purchased the privately owned portion of the islands in 2008 and this non-government organisation continues to work closely with the National Reserve System (NRS) Program to protect other sites of geoconservation significance and add them to the reserve system (Internal linkTLC 2008).
Statewide coverage of differing major types of fluvial, karst and coastal landforms, including the mapping of their spatial distribution at a uniform scale, is available or in preparation. However, detailed Statewide mapping has yet to be completed for other geoconservation themes.
Site integrity refers, for example, to the maintenance of the significant contents or exposures of a bedrock site, the maintenance of the forms of significant landforms, or the maintenance of the profiles and coverage of soils at significant representative soil sites. Note that it is possible to have sites, such as the flooded Lake Pedder, whose forms and contents remain intact (i.e. site integrity is high), although their natural processes no longer function naturally (i.e. process integrity is currently low).
The TGD provides useful information on geoheritage site integrity, with data on the condition (degradation) and conservation status of geodiversity in Tasmania. The site condition indicators detailed in the Internal linkSite Condition of Identified Sites of Geoconservation Significance Indicator below are derived from information recorded on the TGD. The condition indicator (TGD field = Degradation Class) is a qualitative measure of the condition (integrity) of the geoconservation values of a site, based on:
At present, there is no process for systematically reviewing or updating the site condition or conservation status of TGD sites, many of which were listed in the mid–1990s. Changes in the percentage representation of geological, geomorphological and soil attributes in the different degradation and conservation status classes are therefore primarily attributable to new TGD listings, not actual changes in condition status. Therefore, the information presented in this SoE Report only provides a general overview on condition and conservation status.
Process integrity refers to the maintenance of the relevant natural processes operating at, or upon, a site or system of geoconservation value. For example, process integrity refers to the maintenance of the hydrological or other processes which operate in a natural landform or soil system, and which govern the rates and magnitudes of natural change in such systems. In general, process integrity is less relevant to bedrock features or relict landform assemblages rather than to contemporary landform and soil systems whose integrity and continuing evolution is governed by ongoing natural processes. However, understanding how process integrity affects geodiversity is important because it assists in reporting on landscape-scale changes in the environment.
Although the TGD contains some information relevant to process integrity, the data is directed towards assessments of site integrity. Instead, an assessment of process integrity is built into an analysis of a base map (identifying the spatial distribution of the major types or elements within a given geodiversity theme such as fluvial, karst or coastal landform systems), and overlain by appropriate layers that identify the differing condition or conservation status of the theme (i.e. the degree of naturalness or artificially induced change for the types or elements within the theme). In effect, a base map depicting the spatial distribution of differing elements of geodiversity is the essential component that makes the difference between a specialised indicator of the state of geodiversity, and a more generalised environmental indicator.
The Fluvial Systems Project developed a method for defining geomorphic river regions at a Statewide scale (Internal linkJerie et al. 2003). Aspects within the environment that influence river development, character and form defined the geomorphic river regions. These aspects broadly included lithology, climate, geomorphic process history, topography, vegetation and geological processes. Environmental Domain Analysis (EDA) was used as a foundation to produce 90 regions or 'fluvial mosaics' across the State that were found by the analysis to be internally consistent in relation to the environmental controls on river development. The EDA resulted in a map that included 489 different river environment domains, many of which occurred in multiple patches (where a patch is an area that is internally consistent in terms of the system controls on river development and a domain is composed of one or more similar patches). In total, 129 thousand patches of river landscape were identified in the State. This information has been used to characterise rivers from which river styles mapping is being developed to identify catchment characters, fluvial landforms and mosaics, and reference reaches for key fluvial mosaics. The information is being used as a tool to link geo-river conservation priorities with sustainable water management and use. Data from this project has contributed to the CFEV Project and been incorporated into TRCI. More information on the geomorphic landscape mosaics and river regions can be found in the Internal linkRiver Naturalness Indicator.
The CFEV Project has developed a framework for the management, development and conservation of freshwater-dependent ecosystem values in Tasmania based on CAR reserve-design principles. Key products of the project have been an assessment framework and the CFEV database. The database is an information tool that provides environmental data relating to freshwater areas (including groundwater and karst) of low to high conservation management priority (Internal linkDPIW 2008). CFEV data is intended to be a baseline for TRCI. More information on the high conservation value of freshwater ecosystems and the CFEV program can be found though the Internal linkRiver Naturalness Indicator, Internal linkExtent and Condition of Riparian Vegetation Indicator and Internal linkExtent and Condition of Wetlands Indicator, and the DPIPWE External linkThe Conservation of Freshwater Ecosystem Values Program website.
TRCI was established by DPIW (now DPIPWE) to provide a rapid assessment approach to evaluate river health from a total ecosystem perspective (see Internal linkNRM South 2008). TRCI currently assesses five key components of rivers: aquatic life; hydrology; water quality; physical form (geomorphology); and the streamside (riparian) zone. The index has been designed to measure the condition of the whole river ecosystem and will initially monitor the condition of river systems relative to a reference state. The data will contribute to the understanding and management of the physical, chemical and ecological processes that drive river condition, including the provision of a uniform approach to identify geodiversity values and geoconservation threats. More information about TRCI and the rapid assessment of river condition can be found through the DPIPWE External linkIndex of River Condition website.
A base map for the indicators of the state of karst geodiversity in Tasmania exists in the form of an atlas of Tasmanian karst (Internal linkKiernan 1995). The most recent version of the digital Tasmanian Karst Atlas is v.3.0 (2003) is held by DPIPWE and includes all known karst areas in the State (Internal linkSharples 2003). The map does not identify individual karst features such as caves, but maps each discrete area of karstic or potentially karstic carbonate bedrock (initially considered by Internal linkKiernan 1995). According to the karst layer comprising carbonate units and strata containing carbonate units, at 2007, karstic and potentially karstic carbonate rocks occupied approximately 419,012 ha. The actual presence of karst is yet to be confirmed in some cases (Internal linkDPIPWE 2008). Approximately 222,567 ha (53% of the total) was protected in formal and informal reserves on Crown and private land.
It is difficult to report upon known pollution of karst aquifers in Tasmania because there is a paucity of quantitative data on water quality in Tasmanian karst areas. These areas are subject to a spectrum of land use practices, some of which have been identified as actual or potential sources of pollution to karst aquifers (e.g. quarrying, forestry, agriculture, urban development and landfill). The historically widespread practice of using sinkholes and caves for disposing of domestic and agricultural waste in some northern rural karst areas is a potentially significant, but little publicised, threat to groundwater quality (see, for example, Internal linkBenjamin 2008). Further work is required to assess the environmental effects of waste disposal and other practices that impact karst areas. In addition, because of the potential role of karst aquifers in providing long-term indicator sites for surrounding catchment condition, there is scope for including some selected karst sites in the DPIPWE Statewide Baseline Water Quality Monitoring Program (BWQMP).
In order to create an endorsed methodology to monitor and map changes in vegetation extent over time, DPIW (now DPIPWE) commenced the MVEP in 2005. The project compares Statewide Landsat satellite images across a five-year period to detect forest cover changes, which are then verified using information from other sources such as Forest Practices Plans and high-resolution imagery. The mapped changes will be used to update TASVEG and to create a baseline for future monitoring.
Coastal geomorphic mapping has been extended since the 2003 SoE Report and the relevant digital maps updated (Internal linkSharples 2006). These maps comprise the Tasmanian Shoreline Geomorphic Types Digital Line Map v.4.0 (2006) and the Tasmanian Quaternary Coastal Sediments Digital Polygon Map v.4.0 (2006). Shoreline types have been classified using criteria based on sensitivity to erosion in response to sea-level rise and climate change.
In 2007, researchers at the University of Tasmania commenced work on a national project for the Australian Greenhouse Office and Geoscience Australia to produce a line-format geomorphic map of the Australian coastline using a nationally-consistent landform classification system. This national approach has been largely modelled on the approach developed in Tasmania. The national map will be useful for assessing coastal vulnerability to sea-level rise and a range of other applications including input into the national Oil Spill Response Atlas (Internal linkSharples 2007).
The coastal georegion classification attempts to classify the 'overarching controls' that will influence the development of coastal landform types occurring in a coastal georegion. For example, the coastal georegion classification does not provide information on whether sandy beaches will occur in a particular coastal segment, but identifies that if they occur, they will tend to be of a certain type distinct from sandy beaches in other georegions. Therefore, any particular coastal georegion will contain a suite of differing landforms. However, the suite of landforms will be of types distinct from the landforms that have developed in other coastal georegions.
An alternative classification of coastal types is the Integrated Marine and Coastal Regionalisation of Australia (IMCRA v.4.0, 2006). More information on this classification can be found on the Department of Environment, Water, Heritage and the Arts (DEWHA) External linkIntegrated Marine and Coastal Regionalisation website. IMCRA is a classification of broad marine and coastal ecosystem types include geological and geomorphic character, and was developed to facilitate assessment of marine and coastal biodiversity conservation requirements (Internal linkDEH 2006). The latest version of IMCRA combines IMCRA v.3.3 (which provided a marine regionalisation of inshore waters) with the National Marine Bioregionalisation (which extends regionalisations beyond the continental shelf to cover all of Australia's Exclusive Economic Zone) (Internal linkDEWHA 2008). The coarse scale of the IMCRA regions, and the very broad classifications of geodiversity that are used in the framework, means that their use as a base dataset for the development of indicators to report on the state of coastal geodiversity in Tasmania would provide only very broad and generalised indicators when compared to using the more detailed coastal georegions mapping described above. Nonetheless, IMCRA may provide useful information when applied in combination with other types of conservation indicators.
The following indicators summarise the current state of knowledge that contributes to our understanding of geodiversity in Tasmania.
Environmental indicators help track changes in the environment. Indicators can help in gaining an appreciation of conditions and trends and changes in the environment without having to capture the full complexity of the system, which is typically unknowable for most ecosystems: it is inherently complex and always changing, as is human interaction with the environment.
Indicators may be physical, chemical, biological or socio-economic that provide useful information about the whole system. In SoE reporting, indicators are also often classified as to whether they relate to the condition of the environment, pressures caused by people on the environment or management responses (in seeking to reduce pressure and improve condition).
In the 2009 SoE website, an indicator may be used across more than one issue report or chapter. For example, measures of water quality in Tasmania's rivers and streams tell us about the condition of these aquatic systems and are used in this part of the SoE Report (condition of freshwater). They may also tell us about pressures on estuaries receiving water from these rivers and catchments (pressures on estuaries).
Index of geoheritage indicators
Index of geoheritage indicators
Geonconservation conditioninternal SOE link to larger image
Site Condition of Identified Sites of Geoconservation Significance - at a glance
The condition of geoconservation sites listed in the TGD in 2008 is presented in this indicator. Measuring the condition (degradation) of sites listed as having geoconservation significance in the TGD, and the changes in the number of sites in each condition class over time, indicates the level of site degradation and the changes in geoconservation practice in Tasmania.
Geoconservation statusinternal SOE link to larger image
Site Conservation Status of Identified Sites of Geonconservation Significance - at a glance
The conservation status of geoconservation sites listed in the TGD in 2008 is presented in this indicator. It is important to understand the degree to which current tenure and land management regimes are likely to protect or degrade the geoconservation values of a site. This parameter forms a more meaningful indicator of geoconservation significance than would land tenure alone, since some geological features are more robust than others, and not all significant geological features require conservation land tenure protection for their values to be adequately maintained.
Land Cover Modification by Area of Karst Type - at a glance
This indicator details exposed, covered, interstratal karst areas across the State along with karst catchment areas. It also provides a list of key karst sites in Tasmania sourced from the TGD in 2008 and describes karst types according to percentage area under the modified land cover classes. It classifies karst types with >30% modified land cover, 20–30% modified land cover, and <20% modified land cover. The following analysis is subject to the data availability and limitations detailed within the indicator.
Data is included on plantation development that presently occurs over karst areas in the State and information on karst areas with respect to the development, conservation and management of the State's water resources. Given that karst is often found across the landscape rather than being confined to individual properties or by land tenure boundaries, it is important to take catchment areas, drainage patterns and land clearance into consideration when assessing the condition of karst systems (Internal linkBenjamin 2008). It is also necessary to take into account human-induced activities such as waste disposal or the application of fertilizers and pesticides.
River Naturalness - at a glance
This indicator includes river naturalness and fluvial systems mapping. It illustrates some key examples of river styles mapping that are being developed as part of the DPIPWE Fluvial Systems Project in partnership with the NRM regions and Greening Australia. Fluvial mapping aims to identify catchment characters, fluvial landforms and mosaics, and reference reaches for key fluvial mosaics that illustrate geo-river naturalness (see Internal linkJerie et al. 2003). The results of this project have been incorporated into the CFEV Project.
A naturalness assessment of rivers in the Tasmanian river network has been incorporated into the CFEV dataset. 'Naturalness', as defined under the CFEV Project, can be used as an overall index of river condition (Internal linkDPIW 2008). The CFEV assessment indicated that the river network across Tasmania extends 152,941 km. It also identified that a further 4,082 km of artificial pipeline and linking sections within waterbodies extend across certain parts of Tasmania. Artificial pipelines and linking sections were not assessed for condition.
Leven River catchment
Leven River catchmentinternal SOE link to larger image
Woody vegetation change, ~1994–2001
Woody vegetation change, ~1994–2001internal SOE link to larger image
Forest vegetation change, 2000–05
Forest vegetation change, 2000–05internal SOE link to larger image
Non-forest vegetation change, 2000–05
Non-forest vegetation change, 2000–05internal SOE link to larger image
Cleared land within the coastal zone
Cleared land within the coastal zoneinternal SOE link to larger image
Coastal vegetation change, 2000–2005
Coastal vegetation change, 2000–2005internal SOE link to larger image
Extent of Forest and Non-Forest Vegetation - at a glance
This indicator reports on the area remaining and distribution of native forest and non-forest vegetation at the Statewide level. As well the extent of native vegetation communities being the best available measure of ecosystem diversity, it also provides an indication of pressure to karst, fluvial and coastal systems. This indicator draws on data from the TASVEG v.1.3 vegetation map (Internal linkDPIW 2007) and the summary of reservation status for TASVEG vegetation communities (Internal linkDPIW 2008). The Forest Practices Authority compiles data on the maintenance of the Permanent Forest Estate (Internal linkFPA 2007; Internal linkState of Tasmania 2007). Information on changes in the extent of native non-forest communities is available through the Monitoring Vegetation Extent Project (Internal linkTVMMP 2008).
Changes in vegetation cover, especially from deep-rooted to shallow-rooted vegetation types (or visa-versa), has a major effect on important geomorphic hydrological, soil and coastal processes including water runoff and infiltration rates, slope and karst drainage patterns and flow regimes, and soil erosion rates. Changes of vegetation cover to bare urbanised ground also significantly impacts geodiversity.
Rriparian zone (major streams)
Rriparian zone (major streams)internal SOE link to larger image
Extent and Condition of Riparian Vegetation - at a glance
This indicator describes the extent and condition of native riparian vegetation at the catchment and Statewide scales. Retention or loss of riparian vegetation has a major impact on geological and geomorphological (and biological) processes in watercourses, particularly when vegetation loss results in erosion. Consequently changes in riparian vegetation, together with catchment vegetation cover changes, are possibly the two most important pervasive influences on fluvial system integrity.
Data for this indicator draws from the CFEV Native Riparian Vegetation Index (Internal linkCFEV database, v1.0 2005) and TASVEG data on native vegetation communities (Internal linkTVMMP 2006). The indicator also draws on recent riparian surveys (Internal linkDaley 2003 and Internal linkDaley & Kirkpatrick 2004). The following analysis is subject to this data availability and limitations detailed within the indicator.
Sea-level Change - at a glance
This indicator reports on Tasmanian regional implications of data from the National Tidal Centre (NTC) in South Australia, which calculates annual sea-level trends at 35 longer-term sites (>25 years) under the Australian Baseline Sea Level Monitoring Project (ABSLMP) and 16 high accuracy SEAFRAME (SEA-level Fine Resolution Acoustic Measuring Equipment) sites around Australia. Other key references used for this indicator are the Indicative Mapping of Tasmanian Coastal Vulnerability to Climate Change and Sea Level Rise (Internal linkSharples 2006); Historical and Projected Sea-level Extremes for Hobart and Burnie, Tasmania (Internal linkHunter 2008); and the DPIW (now DPIPWE) policy report titled: Sea-Level Extremes in Tasmania: Summary and Practical Guide for Planners and Managers (Internal linkDPIW 2008).
Tasmania is being affected by changes in climate. These changes are leading to a wide range of environmental impacts, including a rise in the level of the seas that has been occurring at a sustained rate, which has not been experienced for at least 5,000 years (see Internal linkHunter 2007). Rises in sea-level is currently being felt along some of the State's coastline through an increased frequency of storm surges and coastal flooding events, coastal erosion and substantial changes to the bathymetry and topography of soft coastal margins (e.g. sandy shorelines). Sea-level rise and associated climatic changes will have long-term geomorphic impacts on coastlines around Tasmania, particularly along exposed low gradient sandy coasts. These impacts include:
Where coastlines remain in a natural state and are more or less undeveloped, dynamic and highly mobile coastal landforms and ecosystems such as beaches, dune systems, wetlands, saltmarshes and intertidal sand flats have the potential to adjust to rising sea-levels (Internal linkSharples et al. 2008). They are also able to adapt to changing groundwater levels and increased frequencies of inundation by migrating landwards, particularly when they are backed by low-lying soft-sediment environments that allow such migration. However, coastlines that are subject to development are less resilient to changes in sea-levels. In addition, if human responses to rising sea-levels are to defend the coast with artificial structures such as sea walls, existing potential for natural shoreline adjustment to the changing conditions will be reduced further. This will result in less natural shoreline and fewer areas for the retreat of vulnerable plants, animals and landforms.
Sea-level projections for the 21st century from the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR) of 2001 and the Fourth Assessment Report (AR4) of 2007 identify that observed sea-level is currently tracking near the upper limit of the IPCC model projections from the start date of the projections in 1990 (see Internal linkRahmstorf et al. 2007; Internal linkIPCC 2001; Internal linkIPCC 2007). The IPCC TAR Report model projections estimated a sea-level rise of between 9–88 cm by 2100. The IPCC AR4 model projections (with a 90% confidence range) revised this estimate and calculated a sea-level rise of between 18–59 cm by 2095 plus an allowance of another 10–20 cm for a potential dynamic response related to the melting of land ice in Antarctica and Greenland (see also Internal linkChurch et al. 2008; Internal linkIPCC 2007; Internal linkChurch et al. 2006; Internal linkEarth Observatory 2006). However, more recent published work suggests that a rise of up to 2 m is possible (Internal linkACE CRC 2008) and it could be more than 5 m by 2100 (Internal linkHansen 2007). CSIRO promotes the range 18–79 cm for Australia (Internal linkCSIRO 2009). Even with a rise of mean sea-level of approximately 50 cm, it is predicated that events which now happen every few years could occur every few days in 2100 and that larger increases in the frequency of extremes could occur in Bass Strait, along the coastline of Western Australia and capital cities such as Sydney, Brisbane and Hobart (Internal linkHunter 2007).
Artificially Modified Coastlines - at a glance
This indicator reports on areas of artificial physical modification of shorelines around the Tasmanian coast. Artificial physical modification of shorelines is a major category of disturbance that not only affects geomorphic processes but also the physical integrity of significant coastal geoheritage sites. The data included in this indicator has been compiled by SoE Unit using the Tasmanian Shoreline Geomorphic Types dataset v1.0–v4.0 (2000–06).
Coastline exposure and wave energy
Coastline exposure and wave energyinternal SOE link to larger image
Vulnerability of Coastal Geodiversity - at a glance
This indicator outlines the vulnerability of various shoreline geodiversity types to erosion and recession caused by wave action and other hazards such as sea-level rise and storm surge flooding. Data was drawn from the Indicative Mapping of Tasmanian Coastal Vulnerability to Climate Change and Sea-Level Rise Project (see Internal linkSharples 2006). The assessment is not complete and further refinement of the assessment methodology, along with baseline monitoring and ground-truthing in the field, is planned.
Coastal landforms, and particularly sandy coasts, are one of the most mobile and dynamically changing geomorphic landforms in Tasmania. Coasts can, and do, change their physical form significantly over relatively short periods. This is a natural phenomenon. Coastal flooding and shoreline erosion have affected Tasmanian coasts repeatedly over the last 6,500 years during a period when the sea-level was mostly steady. More recent sea-level rise has been estimated at 10–20 cm during the last century (see Internal linkCSIRO 2008; Internal linkIPCC 2007; Internal linkChurch et al. 2001). Sea-level rise when combined with the affects of climate change are likely to increase or accelerate past coastal hazards where these existed previously, and initiate new phases of flooding and erosion on some shores that were previously in equilibrium.
Native Vegetation Clearing - at a glance
This indicator aims to report on the rate of clearing (in ha/yr) of terrestrial native vegetation types, by clearing activity. The rate of vegetation clearing provides a measurable estimate of the potential threat to geodiversity. Clearing vegetation has significant effects upon hydrological processes (e.g. alterations to the catchment runoff/infiltration balance, erosion rates and sediment balance in rivers and estuaries, groundwater levels and stream flow regime). These alterations can modify karst, fluvial and coastal geomorphic processes. Land cover modifications within one catchment can also influence the fluvial geomorphic processes within adjacent catchments.
The data included in this indicator is compiled from a number of sources. These sources cannot be compared because they are based on different methods (e.g. TASVEG 1.3, Landsat satellite data for the Monitoring Vegetation Extent Project and Forest Practices Plans). They also have different reporting periods. The indicator outlines these key sources and the key limitations with these data.
Weeds of Significance Present in Tasmania - at a glance
This indicator highlights the distribution of marram grass (Ammophila arenarias) and rice grass (Spartina anglica) in Tasmania. Information on these species was made available through the DPIPWE Weed Management Section and Parks and Wildlife Service (PWS) and is subject to some limitations that are detailed in the indicator. Other information is sourced from coastal values mapping projects known as the Coastal Values of Southern Tasmania (Internal linkDTAE 2007) and the Coastal Values of North East Tasmania (Internal linkDTAE 2007); and the assessment and mapping of foreshore values, condition and pressure in the southern NRM region (Internal linkMingus 2008).
Marram grass is an introduced perennial coastal plant was introduced from Europe over a century ago to stabilise coastal beaches and dunes. However, it spreads rapidly and over long distances. For example, along the southwest coast beaches, it has been found up to 110 km south from the nearest deliberate planting at Ocean Beach (Internal linkPWS 2003). Given its invasiveness, marram grass causes major changes to geomorphic processes in sandy coastlines. This is because marram tussocks effectively trap wind blown sand causing dune building around plants (Internal linkRudman 2003). Large steep faced dunes are also created that contrast with the lower angled foredunes that are associated with native vegetation. These dunes are more prone to wave attack and erosion. In addition, accumulation of sand within marram dune systems can also remove sand from beach, surf and inshore areas affecting sand movement and availability along coastlines. Where sandy coastlines in the State are significantly infested with marram grass, its establishment provides an indication that natural geomorphic processes have potentially been significantly altered in the area. More information on marram grass in Tasmania can be found in the Internal linkPlant Pests (Weeds) and Native Plant Diseases Issue Report.
Rice grass is a vigorous saltmarsh grass that was deliberately introduced from England to Tasmania initially in the late 1920s, but was continued to be planted along the banks of estuaries until the 1970s (Internal linkNHT and DPIWE 2002). For example, it was actively planted to improve navigability in the River Tamar in 1947 (Internal linkSheehan 2008). It has since become established in seven coastal regions in Tasmania, including Australia's two largest infestations, the River Tamar (420 ha) and the Rubicon Estuary (135 ha) (Internal linkDPIPWE 2009). This plant can cause changes to geomorphic processes because its dense growth habit and rhizomatic root network act as a trap for sediments and debris altering the natural rate, magnitude and location of sediment deposition and erosion. These processes elevate shorelines and river banks to create terraces and marsh islands by promoting deposition and accretion. Currently, there are six hotspots located near Smithton, the Rubicon and Port Sorell region, Tamar River, the Bridport region, Little Swanport and the Derwent Estuary near Dog Shear Pont, Old Beach and Elwick Bay. More information on rice grass in Tasmania can be found in the Internal linkEstuarine and Marine Pests and Diseases Issue Report.
Density of Road Networks and Walking Tracks - at a glance
This indicator reports on the density of roading in a region (e.g. catchments and areas of karst type) by providing a measure of the length of roading in each area. It also reports on the density of walking tracks in a region and provides a number of illustrative examples on where key walking tracks are found in the State. The data included in this indicator has been sourced from the DPIW Road Infrastructure Dataset (2008), Tasmanian Karst Atlas v.3.0 (2003) and the PWS Bushwalking Tracks Dataset (2008).
Roading, 4WD tracks, bike tracks and walking tracks provide access which gives rise to a range of pressures on the natural environment (e.g. ecosystems and karst, fluvial and coastal systems). They are often a precursor to changes in land use and land cover, which in turn, affect geology and geomorphological processes. In addition, the roads (and other tracks) themselves have significant effects on runoff rates, slope drainage patterns and flow regimes, as well as soil erosion rates and runoff turbidity. Changes (which will normally be increases) in roading and walking track density within a region will imply a higher likelihood of adverse impacts on the natural environmental processes within that region.
Total sediment to rivers
Total sediment to riversinternal SOE link to larger image
Basslink, geo-monitoringinternal SOE link to larger image
Basslink, net erosion rates
Basslink, net erosion ratesinternal SOE link to larger image
Lower Gordon River
Lower Gordon Riverinternal SOE link to larger image
Lower Gordon River erosion
Lower Gordon River erosioninternal SOE link to larger image
Central Plateau Conservation Area
Central Plateau Conservation Areainternal SOE link to larger image
Macquarie Island erosion
Macquarie Island erosioninternal SOE link to larger image
Potential Area Affected by Erosion - at a glance
This indicator highlights key information on erosion in the State as detailed below. This indicator provides information on both condition and pressure erosional processes because geological and geomorphological landforms can both be formed and damaged by past natural- or human-induced erosional events. Data were sourced from a systematic Statewide survey of water erosion (gully, tunnel, and sheet and rill erosion) that was conducted as part of a Statewide soil and land degradation assessment (Internal linkGrice 1995). Additional data and information were supplied by DPIPWE, Hydro Tasmania, the Tasmanian National Parks Association, and the Australian Natural Resources Atlas (in relation to river basin sediment budgets and erosion monitoring of the middle and lower Gordon River, and erosion on the Central Plateau and Macquarie Island). The following summary is subject to the data availability and limitations detailed within the indicator.
Geoheritage Protection - at a glance
This indicator details the extent of karst found within the CAR Reserve System and new reserves that have been established in karst areas since the 2003 SoE Report. Data was sourced from the Tasmanian Karst Atlas v.3.0 and the LIST held by DPIPWE. It also details karst reserved under the Community Forest Agreement (CFA).
In addition to the TGD, Digital Tasmanian Karst Atlas, Fluvial Systems Project, Tasmanian Shoreline Geomorphic Types Digital Line Map, and Tasmanian Quaternary Coastal Sediments Digital Polygon Map there have been a range of management responses and projects that have been established since the 2003 SoE Report to report on geoheritage in Tasmania and help conserve these sites. Some of these key responses, and other related programs, projects, frameworks and initiatives are listed below.
Geodiversity management legislation
In an effort to protect sites of significant geological values, the External link: LegislationRegional Forest Agreement (Land Classification) Act 1998 was the first direct recognition of 'geological diversity' under Tasmanian legislation (Internal linkHoushold and Sharples 2008). These provisions were then incorporated in the External link: LegislationNature Conservation Act 2002, External link: LegislationCrown Lands Act 1976; External link: LegislationNational Parks and Reserves Management Act 2002 and the associated Forest Practices Code 2000. Under these Acts, geological diversity means 'the natural range of geological, geomorphological and soil features, assemblages, systems and processes' in specific contexts. The External link: LegislationWellington Park Act 1993 also refers to the preservation of any features of geomorphological interest. In addition, the External link: LegislationMineral Resources Development Act 1995 states that a person must not disturb, collect or remove any speleothem (cave formation) from a cave without written approval, and the associated Mineral Exploration Code of Practice 1999 includes guidelines for protecting geoconservation and geological heritage. These provisions may be relevant in some situations of 'environmental harm' arising on private land from 'gross' acts of negligence as outlined in External link: LegislationEnvironmental Management and Pollution Control Act 1994. However, despite these various provisions, Tasmanian legislation does not provide for holistic protection for geoconservation values through statutory mechanisms at the landscape level.
Local government planning schemes in some municipalities now require development applications to address geoconservation values where they are identified as being present in the landscape. For example, off-reserve karst management on public and private land has continued to have a high profile at Mole Creek. A draft planning scheme released by the Meander Valley Council in 2007 contains a karst schedule specifying performance criteria and acceptable standards for minimising adverse impacts to the local karst system (Internal linkMeander Valley Council 2007). The schedule is underpinned by mapping that identifies different zones within the karst based on criteria for environmental sensitivity.
Management policies and strategies
The Tasmanian Reserve Management Code of Practice 2003 specifies appropriate standards and practices for new activities in land-based reserves, and underpins management of formal reserves by the PWS and Forestry Tasmania. Geoconservation values are addressed in detail where conservation is 'achieved primarily through the protection and maintenance of geological (rock), geomorphological (landform) and pedological (soil) features, systems and natural ecosystem processes' (Internal linkPWS et al. 2003). The Reserve Code complements the geoconservation provisions of other major State codes of practices such as the Forest Practices Code 2000 and Mineral Exploration Code of Practice 1999. The State Coastal Policy 1996 (Internal linkDTAE 1996) and Proposed State Coastal Policy 2006 (Internal linkDEPHA 2006) also refer to the protection of geology and geoheritage places.
The Board of the Environment Protection Authority (EPA) has produced guidelines to assist proponents prepare Development Proposal and Environmental Management Plan (DPEMP) assessments and environmental management plans for Level 2 activities under the External link: LegislationEnvironmental Management and Pollution Control Act 1994 (Internal linkEPA 2008). Section 4.7.2 (e) of the guidelines requires proponents to consider 'effects on sites of geoconservation significance or natural processes (such as fluvial or coastal features), including sites of geoconservation significance listed on the Tasmanian Geoconservation Database'. The guidelines aim to promote a more integrated approach to considering geoconservation values in the planning and assessing of major developments.
DPIPWE has developed a Consultants Brief regarding the minimum requirements for information needed to enable the Tasmanian Government to assess the potential impact/s of proposed activities on biodiversity and geodiversity (Internal linkDPIW 2004). Consultant reports may be required as part of, for example, a DPEMP assessment, a local government planning submission, or a community group wishing to undertake rehabilitation works. An assessment of significant geoheritage and relevant conservation activities is required if a site is listed on the TGD.
As part of the regional Natural Resource Management (NRM) strategy development process, position papers have been developed for geoconservation and geodiversity (including rocks, karst, rivers and coasts) by NRM South and NRM Cradle Coast (Internal linkNRM South 2003; Internal linkNRM Cradle Coast 2003). Information presented in these documents has been used to inform the development of resource management strategies for the northern, southern and Cradle Coast NRM regions (Internal linkNRM Cradle Coast 2005; Internal linkNRM North 2005; Internal linkNRM South 2005). These position papers and strategies recognise that there has been a limited assessment of the condition of Tasmania's geodiversity. Key issues identified in the strategies that relate to geoconservation in the NRM regions include:
Various management plans have been developed by the NRM regions to identify and protect sites of geoconservation significance. For example, NRM North and Bushways Environmental Services developed a Coastal Management Plan for Tomahawk in 2008 that includes actions to protect the north-east Tasmanian Pleistocene aeolian system that covers most of the Tomahawk area (Internal linkNRM North and Bushways Environmental Services 2005).
Other management plans have been completed for a number of areas of high geoconservation significance managed by PWS. The plans prescribe policies and actions for protection of geodiversity. They include the Macquarie Island Nature Reserve and World Heritage Area Management Plan 2006 (Internal linkPWS 2006), Mole Creek Karst National Park and Conservation Area Management Plan 2004 (Internal linkPWS 2004), The Nut State Reserve Management Plan 2003 (Internal linkPWS 2003), Moulting Lagoon Game Reserve (Ramsar Site) Management Plan 2003 (Internal linkPWS 2003), Kent Group National Park (Terrestrial Portion) Management Plan 2005 (Internal linkPWS 2005) and Southport Lagoon Conservation Area, George III Monument Historic Site and Ida Bay State Reserve Management Plan 2006 (Internal linkPWS 2006). Recent closure of the Leprenna Track under the Southport Lagoon Conservation Area Management Plan has alleviated a source of serious ongoing damage to organic soils. Work has also commenced on the preparation of a management plan for caves and karst on land managed by PWS in its Southern Region administrative unit.
Many of the features found in the TWWHA are listed internationally as sites of geoconservation significance and included on the World Heritage List. However, this list has been criticised for it focus on biodiversity values and its failure to adequately represent areas and sites of geological significance (the exception of a relatively few fossil sites). The Global Indicative List of Geological Sites (GILGES) was also established in the early 1990s by the United Nations Educational, Scientific and Cultural Organization (UNESCO), IUCN and International Union of Geological Sciences (IUGS). This list includes hundreds of geoconservation sites that are considered to be of 'first-class' importance, representing outstanding examples of the Earth's history and significant ongoing geological processes (see Internal linkGray 2004). The GILGES has been modified and reworked since the initial compilation and now includes natural networks of sites that 'represent' geodiversity. Geoparks have also been established since 2004 to protect internationally significant geological heritage and officially endorsed by UNESCO as an integral part of their network/system of protected areas together with sites on the World Heritage List and the Man and the Biosphere Network of Biosphere Reserves (the Biosphere reserves network). Although Tasmania has yet to establish a Geopark, they may offer an additional management option in the future. More information on Geoparks is provided in the embedded document Internal linkGeoparks in Australia or through the External linkUNESCO website.
Other programs, projects, frameworks and initiatives
Collaborative efforts to identify geoheritage and protect sites of significance are continuing to grow in Tasmania. Government agencies, local government, private industry, NRM groups, non-government organisations and private landholders are increasingly coming together to implement management programs and plans of action to protect geoheritage on public and private land. For example, DPIPWE, PWS, Forest Practices Authority (FPA), Hydro Tasmania and NRM regions all provide information on geomorphology and various actions to protect significant sites on their websites, with most management documents, guidelines and brochures made available for download.
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