Water Chapter
Aquatic Health
Issue Report

Background

Meander Riverinternal SOE link to larger image

Source: Photograph courtesy of Tourism Tasmania and Dennis Harding

Aquatic health is a concept used to describe the condition and functionality of an aquatic ecosystem. 'Health' has been defined by the National Land and Water Resources Audit (NLWRA) as a measure of the overall status and likely changes in the condition of different components of an ecosystem (Internal linkAustralian State of Environment Committee 2001). Therefore, it is one of the key tools available in assessing the state of the environment both in terms of the condition of aquatic ecosystems and the pressures on the systems arising from activities on the land.

An aquatic ecosystem consists of the animals, plants and micro-organisms that live in water, and the physical and chemical environment and climatic regime with which they interact. Water may be either running such as in a Internal linkriver or stream that has a dynamic flow, or still such as in a Internal linklake or wetland. Running water and still water is illustrated in the images at the beginning of this section and in the following diagrams. This Issue Report primarily focuses on aquatic ecosystems within riverine and lake environments. Wetlands are assessed in more detail in the Internal linkWetlands Issue Report.

Dynamic flow

Stream and river environmentsinternal SOE link to larger image

Still water

Lake and wetland environmentsinternal SOE link to larger image

A healthy aquatic ecosystem should be able to support and maintain levels of biological diversity and species abundance, and key ecological processes that are as comparable as possible to that of natural habitats within a region (Internal linkSchofield & Davies 1996).

Undisturbed aquatic ecosystems perform many functions, including the break down and recycling of leaf litter and other detritus in a waterway, supporting terrestrial ecosystems, and so on. As well as their intrinsic values, some of these functions may be of particular value to human society, for example, sustaining species that are used for sport (e.g. trout fisheries).

Aquatic health may vary in definition for different people, depending on whether emphasis is placed on social or ecological values. It is often described from a human-centred perspective as the river or lake's ability to meet community expectations and uses, such as environmental, recreational, aesthetic and production expectations (Internal linkCRCFE 2002). However, the environmental movement has triggered a greater appreciation of the natural and ecological values of inland waters, particularly rivers, through the concepts of wilderness and biodiversity—and through the more formally encapsulated government adoption of principles focused on ecologically sustainable development (Internal linkSchofield & Davies 1996). In this context, any human disturbance to a river or lake may be regarded as a reduction in aquatic health.

Tasmania's aquatic ecosystems are probably the best preserved in southeast Australia, with many rivers and lakes in the southwest of the State and Central Plateau remaining in relatively pristine condition. In other areas specific reaches and individual wetlands also retain essentially natural character.

Loss of aquatic values is associated with past and/or present instream, riparian and catchment modifications or practices that have led to social, economic and material costs at local, catchment and regional scales. Loss of aquatic values has been associated with:

  • loss of aquatic gene pool, food, shelter and habitat (Internal linkRead 1999);
  • reduction in riparian vegetation;
  • elevated loads of total phosphorus and suspended solids;
  • introduction of exotic species and the cost of their control;
  • degradation of channels, river banks and floodplains and the cost of their rehabilitation;
  • pollution of waterways by toxic algal blooms; and
  • loss of educational, scientific and recreation values.

The following diagrams outline some of the factors that impact upon aquatic health. The first diagram illustrates the affects of riparian removal and catchment degradation of rivers that can result in bank erosion, blooms of filamentous algae and a simplified biotic system. The second diagram illustrates the hydrological cycle and potential land use impacts on this system such as stormwater runoff, stream erosion, salinity, rural tree decline and the removal of riparian vegetation.

The effects of riparian vegetation removal and catchment degradation on rivers

The effects of riparian vegetation removal and catchment degradation on riversinternal SOE link to larger image

Source: Australian Catchment, River and Estuary Assessment - NLWRA 2002

Hydrological cycle with land use impacts

Hydrological cycle with land use impactsinternal SOE link to larger image

Source: SoE Unit

In Tasmania, the protection of environmental values (PEVs) including the protection of pristine or nearly pristine aquatic ecosystems and modified ecosystems for their production qualities (e.g. the harvesting of edible fish, crustacea and shellfish), is a significant component of the 'State Policy on Water Quality Management 1997' (Internal linkDPIWE 1997).

An assessment of aquatic health helps to determine the pressures that are likely to be affecting a river or lake and/or provides a baseline to assess any possible changes in the condition of the waterbody. This knowledge helps land and water managers including farmers to target effective management in protecting and/or improving aquatic health. Some of the key pressures on aquatic ecosystems that continue in Tasmania, include:

  • changes in natural flow regimes due to drainage, water extraction and water supply;
  • groundwater extraction and overuse;
  • modification and destruction of aquatic habitats;
  • barriers to the movement of fish that reduces their ability to spawn and breed;
  • floodplain isolation and the drying of floodplain ecosystems;
  • changes to catchment hydrology through land clearance or intensification of land use;
  • removal or modification of riparian vegetation;
  • nutrient, sediment and pollutant inputs affecting water quality; and
  • the introduction of exotic species.

More information is available on Tasmanian aquatic health through External linkState of Rivers and External linkAnnual Waterways Monitoring Reports prepared by the Water Resources Division of DPIPWE. The Waterways Monitoring Reports are completed annually and they examine ecological health based on the monitoring and assessment of hydrology, physical and chemical characteristics, and biological components. The Water Information System for Tasmania (External linkWIST) has also been developed to access Tasmanian freshwater related information.

Assessing and measuring the current situation

In this Issue Report rivers and lakes are assessed in terms of their biological condition, degree of naturalness (least disturbed), the level of catchment land tenure security, and the level of conservation management priority needed for protecting their ecosystem values. This approach has some limitations. Whist many aquatic health monitoring programs rely entirely on population surveys of aquatic invertebrates, many stream managers are now recognising that robust indicators of the physical health of streams (such as an index of physical form, suspended/dissolved load and bedload) are also critical, and in some cases may be a more powerful tool than biological indicators alone.

There are also difficulties in selecting appropriate and reliable indicators of aquatic health and the appropriate scale at which to accurately measure and interpret the results about 'health' accurately.

This is because there are complex interactions within aquatic ecosystems between plants, animals and the physical and chemical characteristics of the environment. They vary in type (e.g. lowland, floodplains, wetlands and mountainous) and with changing climatic conditions. Furthermore, ecosystem health can be measured differently depending upon whether the management goal is focused on the protection of ecological values or human use values (Internal linkAustralian State of Environment Committee 2001).

An assessment of aquatic biota through macroinvertebrates overcomes some of these difficulties as they provide an integrative measure of a stream's condition. Aquatic macroinvertebrates respond to all aspects of water quality and quantity as well as habitat condition. They depend on the stream throughout all or most of their life, and being of limited mobility, they also effectively integrate environmental conditions over time (Internal linkMetzeling et al. 2001).

There are also recognised limitations in some of the CFEV indicators. For example, catchment tenure security is, in some cases, a poor indicator of condition for the following reasons:

  • There was considerable degradation before gazettal of many reserves (e.g. Central Plateau in WHA). When unmanaged this degradation is continuing.
  • Current on-going impacts (e.g. recreational vehicle use in coastal reserves) sometimes mean that reserved lands are degrading at a faster rate than other tenures.

The following photographs show macroinvertebrates that both contribute to, and are indicators of, the aquatic health of Tasmania's rivers and lakes. The macroinvertebrates highlighted are the caddis fly larva, log cabin caddis fly larva, damselfly larva, micro-caddis larva, stonefly and isopod.

Aquatic Macroinvertebrates

Caddis fly larvainternal SOE link to larger image

Log cabin caddis fly larvainternal SOE link to larger image

Damselfly larvainternal SOE link to larger image

Micro-caddis larvainternal SOE link to larger image

Stoneflyinternal SOE link to larger image

Isopodsinternal SOE link to larger image

Ideally, several biological measures would be useful in assessing aquatic health (e.g. fish, water plants, waterbirds, algae, and riparian vegetation). Riparian vegetation is fundamental in maintaining healthy aquatic ecosystems and is considered in this SoE Report as a separate issue (see the Internal linkRiparian Vegetation Issue Report). In Tasmania, the most extensive aquatic biological dataset available is for aquatic macroinvertebrate communities from the National River Health Program (NRHP) (see External linkLand & Water website) using the AUSRIVAS rapid biological assessment method in rivers and streams. The Tasmanian component of the NRHP has assessed the ecological condition of more than 500 test sites on rivers across the State since 1993. The data from this assessment is presented in the Internal linkAUSRIVAS River Survey Indicator.

The majority of these sites assessed as part of the NRHP were used to develop six Statewide river health models. A number of catchments have been sampled more intensively for State of Rivers (SoR) reporting (see External linkDPIPWE website). To assess the effectiveness of river health models, a number of test sites were sampled to test the ability of the models to detect a range of impacts or pressures on aquatic ecosystems from land uses including mining agriculture, plantation forestry, and river regulation.

Further information is available through DPIPWE's External linkMonitoring River Health Initiative website.

The upgrading of the DPIPWE network of stream gauging sites has significantly improved the coverage and availability of data on river health (as well as water quality and streamflow) since the 1997 and 2003 SoE Reports. DPIPWE now undertakes a comprehensive Statewide Baseline Water Quality Monitoring Program (BWQMP). The monitoring program also includes river health sampling and commenced in November 2003. Sixty stream sites were chosen for regular river health reporting from 2003–04 (conducted across the 48 Tasmanian Land and Water Management Catchments). In 2008, the BWQMP comprised monthly monitoring at 52 sites across the State where a range of water quality parameters were monitored to provide the backbone for baseline monitoring of ambient water quality in Tasmania (Internal linkDPIW 2008). Of the 52 sites, continuous water quality data is collected at a subset of 37 sites. It also assists land and water managers to gauge Tasmania's environmental performance against the Tasmania Together Environmental Benchmarks (see External linkwebsite).

Monitoring of aquatic health has also been undertaken on specific rivers, for example the Meander, Mersey, Clyde and Great Forester Rivers in relation to monitoring environmental condition under Water Management Plans. Further information on river health in specific river catchments can be obtained through the Waterways Monitoring Reports on the External linkDPIPWE website.

Similar monitoring of aquatic health (macroinvertebrates) and other biota (e.g. fish) is conducted by Hydro Tasmania for rivers and lakes that are subject to regulation, but these data were unavailable for presentation in this SoE Report. Monitoring of aquatic health in the Gordon River has also been carried out as part of environmental assessment for the Basslink Project.

As part of the Natural Resource Management (NRM) Framework, water resource monitoring is being conducted. For example, NRM North began sampling sites in 2004–05 using AUSRIVAS methodology. This monitoring forms part of the Northern Water Monitoring Program and aims to provide an indication of the state of water resources in northern Tasmania. AUSRIVAS data are available for all these sites and are presented in the Internal linkAUSRIVAS River Survey Indicator below.

In 1998, the Wild Rivers Assessment (Stein et al Internal link1998 and Internal link2001) was conducted on Tasmanian rivers to provide a full and detailed inventory of the number of rivers that were classified as being in an undisturbed state (see Internal linkWild Rivers Map). A river was only considered undisturbed (wild) if its catchment was intact. A national inventory known as Australia's Rivers and Catchment Condition Database (formerly the Wild Rivers Database) (see External linkDepartment of the Environment, Water, Heritage and the Arts website) was established and it identifies wild or natural rivers throughout Tasmania and Australia. While this assessment has not been updated and the 2003 SoE Wild Rivers Issue and Indicator are not supported in this SoE Report, it continues to be an important inventory and source of information. Further information is also available through the DPIPWE External linkWild Rivers Website.

The 1998 Wild Rivers Assessment indicated that Tasmanian wild rivers make up 25% of the total rivers distinguished on the 1:250,000 scale AUSLIG topographic maps (the Australian Surveying and Land Information Group) and TOPO-250K digital database. Many of these wild rivers are located in the southwest of the State. Ninety-six per cent of Tasmania's wild rivers are within the Comprehensive, Adequate and Representative (CAR) Reserve System as defined during the Regional Forest Agreement (RFA). The remaining four per cent of the wild rivers are found outside the CAR Reserve System are on private, council and Hydro Tasmania land. The DPIPWE administered External link: LegislationThreatened Species Protection Act 1995 and External link: LegislationAboriginal Relics Act 1975 apply to all land tenures and therefore afford these wild rivers some protection. This data has not been directly updated in the SoE Report.

In 2002, the Tasmanian Conservation of Freshwater Ecosystem Values (CFEV) Project (see External linkDPIPWE website) began to identify where important freshwater values exist on Crown and private land. As outlined in the following table, CFEV assessed rivers, estuaries, lakes and waterbodies, wetlands, saltmarshes, karst and other groundwater dependent ecosystems.

Total number and length (km) or area (ha) of each ecosystem theme assessed using the CFEV framework

Ecosystem theme Total number of spatial units Total length (km) or area (ha) of spatial units
Rivers 350 524 152 941
Estuaries 113 110 666
Lakes/waterbodies 1346 137 042
Wetlands 20 597 206 790
Saltmarshes 336 5745
Karst 334 410 395
Other groundwater dependent ecosystems 115 (points only) n.a.

Source: Internal linkHardie 2006


The aim of CFEV is to provide a strategic framework to ensure that high priority freshwater values are appropriately considered in the development, conservation and management of the State's water resources. In determining freshwater values, CFEV assessed various criteria for ecosystem themes such as rivers and lakes across the State, including naturalness (condition), catchment land tenure security and conservation management priority. These data are presented within the 'Indicators and the 'What has been achieved' sections below.

While similarities exist between the Wild Rivers Assessment and the CFEV River Naturalness assessment, their methodologies differed. Wild rivers are defined as having their entire catchments unimpaired, while CFEV naturalness scores can be assigned to individual sections of river, which can vary throughout the catchment. This helps to explain the varying results between the Wild Rivers Assessment and CFEV river naturalness assessment: 25% of rivers in Tasmania are considered to be wild and undisturbed (Wild Rivers Assessment) compared to 75% of rivers in the State being in a near natural condition (CFEV assessment). As a result, direct comparisons cannot be made between these two assessments and therefore, trends and changes in rivers using these assessments are cannot be reported.

The results of the Wild Rivers Assessment were only considered preliminary, as substantial improvements were deemed to be possible in the drainage analysis, the primary disturbance database and the model (Internal linkStein et al. 1998). Limitations were also highlighted in the Wild Rivers Assessment procedure relating to underlying assumptions in the river disturbance model and the supporting data used. There was a distinct lack of information available relevant to river condition. This included the condition of riparian vegetation, changes in fire frequency and intensity, the presence of exotic species, the intensity of catchment grazing by feral animals and the location of river engineering works (Internal linkStein et al. 2001). Whilst the CFEV Project has reduced some of these limitations with improved data and analysis processes (e.g. improved drainage analyses), there are still several data gaps that should be considered when interpreting the CFEV outputs (these gaps are described in the CFEV Technical Report (Internal linkDPIW 2008).

The National Land and Water Resources Audit (NLWRA) conducted an Australia-wide catchment and habitat condition assessment to provide information about the national causes of river degradation (Internal linkNorris et al. 2001), which was reported on in the 2003 SoE Report. This assessment has not been updated, resulting in the 2003 SoE 'Assessment of River Condition (ARC) Indicator' not being supported in this SoE Report.

In Tasmania, a derived version of the Victorian Index of Stream Condition (see External linkwebsite) was used in some catchment assessments for SoR reporting, although it does not provide a Statewide coverage. Limited assessments of frogs, fish, threatened aquatic fauna and algae have also been conducted for these same catchments. Further information on these assessments can be found on the DPIPWE website for External linkState of Rivers Reports. A collaborative project between NRM and DPIPWE began in 2006 to develop a Tasmanian River Condition index (TRCI). The IRC has Statewide applicability and aims to provide a comprehensive assessment of river condition based on physical stream form, streamside habitat and hydrological connectivity. It also includes aquatic life and water quality sub-indices. The TRCI provides an index of change from a natural state. Further information on the TRCI is available from External linkDPIPWE.

Indicator introduction

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. 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). However, where possible the interpretation of the indicator is provided from the perspective of the path that the reader has taken in the website.However, where possible the interpretation of the indicator is provided from the perspective of the path that the reader has taken in the website.

Index of aquatic health indicators

Condition indicators Pressure indicators Response indicators
Indicator Indicator description
AUSRIVAS River Survey Assemblages of macroinvertebrates in rivers as assessed by AUSRIVAS to determine river health
River Naturalness Naturalness ranking (integrated biophysical condition) for each river section from the CFEV Project presented as total length across the state and per catchment
Extent and Condition of Lakes and Waterbodies Naturalness ranking (integrated biophysical condition) forlakes and waterbodies from the CFEV Project
Waterbird Population Trends This indicator provides a measure of population trends in waterbirds.
Threatened Species Status The number of species presumed extinct, endangered, vulnerable or rare
River Reservation The level of catchment land tenure security along river length, and the extent of the Tasmanian Reserve Estate by catchment
Lake and Waterbody Reservation Naturalness ranking (integrated biophysical condition) for each river section from the CFEV Project presented as total length across the state and per catchment

There are no indicators of pressure on aquatic ecosystems included in this Issue Report.


Indicators

Riffle river health ratings

Riffle river health ratingsinternal SOE link to larger image

Source: Internal linkDPIWE 2005

Base topographic data provided by the LIST

Edgewater river health ratings

Edgewater river health ratingsinternal SOE link to larger image

Source: Internal linkDPIWE 2005

Base topographic data provided by the LIST



AUSRIVAS River Survey - at a glance

Data availability for this indicator draws from stream site assessments conducted over the period 1994–2005. The following analysis is subject to this data availability and some limitations that are detailed within the indicator.

  • An overview of available AUSRIVAS river health outputs for reference and test site condition is provided in the Internal linkriffle and Internal linkedgewater river health maps. The most recent AUSRIVAS output available is presented for each site from the period 1999–2004. Not all sites are sampled every year due to different management priorities. As a result, no direct comparisons have been made with the data reported in the 2003 SoE Report.
     
  • Sixty stream sites have been chosen for regular aquatic health reporting as part of the External linkTasmania Together process and will assist Statewide long-term assessment. Base levels were determined in 2003–04 where approximately 49 (82%) of the 60 sites were in good condition (unimpaired), 10 (17%) sites were significantly impaired and one (2%) site was severely impaired. There was a small overall change in site condition between 2003–04 and 2005–06: two significantly impaired sites improved and were re-assessed as being in good condition, one severely impaired site improved to being assessed as significantly impaired, and two sites previously in good condition were assessed as being significantly impaired. There was little fluctuation in site condition during this period, with only three sites initially in good condition declining to being re-assessed as significantly impaired in 2004–05 before returning to a good status in 2005–06. Six sites also changed status between 'reference' and 'richer than reference', but both of these categories are generally considered to indicate good condition. Limitations on this interpretation are highlighted within the Indicator.
     
  • AUSRIVAS outputs were available for 11 of the 60 Tasmania Together sites for long-term comparison between the 2005–06 and 1994–95 sampling periods. Each of these sites predominantly remained in good condition over the reporting period. Four sites indicated a decline in one habitat feature (edge or riffle) to a 'significantly impaired' state for one sampling year each before a subsequent return to good condition. The edge habitat of a site located on the South Esk River at Cokers Rd was also rated as 'significantly impaired' in 2005–06, while it's riffle habitat remained in good condition.
     
  • As part of the Northern Water Monitoring Program (NWMP), the NRM North Region sampled 50 sites in 2004–05. Approximately 30 sites (60%) were found to be in good condition. Some sites that are richer than 'reference' may be biological hotspots. However, 19 sites (38%) were found to be significantly impaired. The Kings Meadows Rivulet site at Punch Bowl Reserve was assessed as being impoverished, which is likely to indicate a severe impairment of water and/or habitat quality probably related to the surrounding residential and light industrial land use.
     

River naturalness score (CFEV)

River naturalness score (CFEV)internal SOE link to larger image

Source: Internal linkCFEV database, v1.0 2005



River Naturalness - at a glance

'Naturalness' as defined under CFEV may be used as an overall index of river condition (Internal linkDPIW 2008). The CFEV Project indicated that the river network across Tasmania extends 152,941 km. The rivers in this network have been assessed for naturalness. CFEV also noted 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.

  • The naturalness assessment found 114,175 km (75%) of the State's river length to be in near natural condition and 24,478 km (16%) to be severely altered from their natural condition.
     
  • An assessment of river naturalness across the 48 Land and Water Management Catchments in Tasmania found that catchments retaining more than 80% of their total river length in a near natural condition included the George, Huon, Swan-Apsley, Pieman, King-Henty, Scamander-Douglas, Arthur, Gordon-Franklin, Nelson Bay, Port Davey and Wanderer-Giblin catchments.
     
  • In contrast, the Meander and Brumbys-Lake catchments had more than 60% of their total river length severely altered from their natural condition.
     

Lake and waterbody naturalness score (CFEV)

Lake and waterbody naturalness score (CFEV)internal SOE link to larger image

Source: Internal linkCFEV database, v1.0 2005

Base topographic data provided by the LIST



Extent and Condition of Lakes and Waterbodies - at a glance

The CFEV Project (Internal linkDPIW 2008) provides an assessment of the comprehensiveness, adequacy and representativeness of lakes and waterbodies in Tasmania, including their naturalness (condition) and extent. Naturalness (condition) and extent as it applies to lakes and waterbodies is presented in this Indicator.

  • There are 1,346 lakes and waterbodies across Tasmania which cover a total area of 137,042 ha. Of the total number of lakes and waterbodies, 43% are still in a natural or near-natural condition. However, only 5% of their total area has not been altered. Up to 81% of the total lake area has been severely altered and 15% has been significantly altered.
     
  • The discrepancy between the number and area of lakes altered is related to several large lakes that have been regulated, modified or impacted in some way.
     
  • The West Bioregion highlights this difference particularly well as it contains several large hydro-electric lakes (e.g. Lake Pedder and Lake Gordon). Of the 119 lakes in this bioregion, 70% are in a natural or near-natural condition. However, 99% of the total lake area (58,215 ha) has been severely altered.
     
  • The Central Highlands Bioregion contains the most lakes of all the bioregions in Tasmania. This bioregion has 903 lakes that cover an area of 56,484 ha. Whilst 46% of these lakes are considered to be in natural or near-natural condition, 68% of the total lake area has been severely altered and 25% significantly altered.
     
  • More than three quarters of the lake area within six of the nine bioregions have been severely altered. Of these, more than 55% of the total number of lakes found in the King, Northern Midlands and Northern Slopes bioregions have been severely altered.
     
  • Some of the key influences on lakes and waterbodies within Tasmania include the creation of artificial lakes for hydro-electricity and abstraction as well as catchment disturbance of natural lakes. These influences are discussed in more detail within the Internal linkWater Extraction and Storage Issue Report and Internal linkCatchment Land Use Activities Issue Report.
     

Waterbird counts by zone, 1990–2008

Waterbird counts by zone, 1990–2008internal SOE link to larger image

Flinders Island, Google Earth Image, showing drying of wetland habitat for waterbirds

Flinders Island, Google Earth Image, showing drying of wetland habitat for waterbirdsinternal SOE link to larger image

Lake Dulverton satellite image, 2007

Lake Dulverton satellite image, 2007internal SOE link to larger image



Waterbird Population Trends - at a glance

This indicator reports on the trends and changes in waterbirds. Population trends tell us about the cumulative pressures faced by a species across their entire range and at different stages in their life-cycles. The cumulative pressures faced by waterbirds also provide an indirect by useful measure to assess the health of aquatic systems. This is because waterbirds are highly sensitive to environmental changes and habitat loss and degradation. In Tasmania, changes to riparian and wetland environments are the greatest threats to waterbird populations because they provide critical habitat for the survival of these water dependant species.

The importance of healthy aquatic ecosystems to the survival of waterbirds in Tasmania is highlighted in the publication The State of Australia's Birds 2004. Here it states that 'in Tasmania recent changes in weather patterns have left waterbird habitat starved of water, while drought has brought higher numbers of previously uncommon species, presumably as they seek refuge from the dry conditions on the mainland' (Internal linkKidd 2003). Since this time, there has also been increasing evidence to suggest that drought conditions since 2006 and the uncertain impacts of climate change on Tasmania's riparian and wetland ecosystems has intensified. In particular, the publication The State of Australia's Birds 2007, highlights that some Australian birds are increasingly showing changes in there consistent with climate change with one of the most evident changes being a range shift southwards. In particular, in the face of climate change 'wetland birds that are dependant on freshwater habitats starved on water or which will be inundated by salt water will have limited means to adapt' (Internal linkOlsen (ed) 2007).

Data presented in this indicator was sourced from the Biodiversity Conservation Branch within the Department of Primary Industries and Water (DPIW). The data were collected from eight zones in Tasmania as follows: Zone A (Furneaux Group); Zone B (northwest); Zone C (north coast); Zone D (northeast); Zone E (east coast); Zone F (central); Zone G (lower Derwent); and Zone H (south, including Bruny Island).

However, a significant limitation with the data is the absence of available data on the extent of migration of waterbird species to and from mainland Tasmania. It is possible that Tasmania is serving as a refuge for mainland waterbirds following the drying of significant riparian ecosystems including from river, lake and wetland habitats on mainland Australia. In addition, it is often difficult to observe short-term trends, particularly in species such as ducks that may live for 10 years or more.

Five species of native duck namely; black duck, mountain duck (shelduck), wood duck, chestnut teal and grey teal are hunted in Tasmania during an open season usually held from early March to early June. DPIW monitors their population trends. While the primary purpose of these counts is to monitor the harvest, they also provide invaluable long-term data on population trends and the state of the environment affecting these species.

  • State-wide surveys of farm dams are undertaken to monitor the impact on wood duck of harvesting during the duck seasons. Waterbirds found in 485 dams in all areas of the State were first counted in 2004 were counted again in 2005, 2006 and 2007. A report was prepared, which concluded that wood duck numbers did not decline and that hunting did not appear to threaten the population (Internal linkDPIW 2008).
     
  • Notwithstanding, total waterbird counts have been down in recent years. Whilst poor years have been experienced in the past, these have been interspersed with waterbird population recovery periods coinciding with wetter years. These population recovery periods have not been experienced in recent times. The total counts also mask a number of important zone-by-zone and specific species trends.
     
  • The clumping effect has been the strongest trend evident in the waterbird counts in recent years. Waterbirds will clump when water or food become scarce in their usual habitat. Clumping has occurred of waterbirds into waterbodies and wetlands into the north of the State, particularly the Tamar River. In 2008, 25% of all grey teal in the State were counted in the Tamar River (Stewart Blackhall pers. com.). Low river naturalness was identified by the Tasmanian Conservation of Freshwater Ecosystem Values (CFEV Project) for the Tamar Estuary. In addition, the majority of the Tamar Estuary has a low percentage of river length within protected security land tenure.
     
  • In the Furneaux Group, mountain duck is showing a downward trend. The chestnut teal is showing a slight upward trend in the north of the State, highlighting the clumping effect into zones that have better relative water and food supply. The majority of the Furneaux Group has a low percentage of river length with protected land tenure security.
     
  • In the northeast, black duck and chestnut teal show declining population trends. Black duck is also showing a declining trend in monitoring zones in central Tasmania and in the southeast. These areas also have mixed river naturalness and mixed protected land tenure security.
     
  • A recent study has highlighted the relationship between waterbird counts and rainfall at Lake Dulverton near Oatlands (Internal linkd'Arville and Blackhall 2008). The graph of waterbird counts and rainfall shows a downward trend in waterbird populations, indicating that even when there is water in Lake Dulverton, other factors such as insufficient food may also be influencing waterbird population recovery. In this regard, the Jordan Catchment is one of the driest catchments in the State. The average annual rainfall across the catchment is approximately 500–600 mm per annum. It is also a highly modified catchment that was identified as having low river naturalness by the CFEV Project. In addition, majority of the Jordan Catchment has a low percentage of river length within protected security land tenure.
     

Example observations of threatened flora occupying freshwater riparian habitat

Example observations of threatened flora occupying freshwater riparian habitatinternal SOE link to larger image

Threatened invertebrate species observations, Natural Values Atlas (NVA)

Threatened invertebrate species observations, Natural Values Atlas (NVA)internal SOE link to larger image

Threatened vertebrate species observations, Natural Values Atlas (NVA)

Threatened vertebrate species observations, Natural Values Atlas (NVA)internal SOE link to larger image



Threatened Species Status - at a glance

This indicator reports on the number of species (including freshwater, riparian, lake and saltmarsh species) presumed extinct, endangered, vulnerable or rare, as listed in the Tasmanian External link: LegislationThreatened Species Protection Act 1995. The number of aquatic species listed as threatened provides indicates a loss of species diversity which in turn, provides an indirect measure to assess the health of aquatic systems. Data has been complied from data obtained from the Threatened Species Unit within DPIW, the Natural Values Atlas (NVA), previous SoE Reports and other relevant documentary sources.

Overall, there has been no apparent change since the 2003 SoE Report to the listings of threatened species associated with inland waters (freshwater and riparian habitats) under the Threatened Species Protection Act 1995 in Tasmania. Listed species include 14 freshwater plant species, over 30 riparian plant species and 76 species of freshwater fauna.

  • Of the 76 species of freshwater fauna, there are 12 native fish species, five crayfish (lobsters) and several other aquatic invertebrates listed on the Threatened Species Protection Act 1995 and eight fish recognised by Commonwealth legislation, External link: LegislationEnvironment Protection and Biodiversity Conservation Act 1999. Two of these species, the giant freshwater lobster ( Astacopsis gouldi) and the Australian grayling (Prototroctes maraena) are 'protected fish' under the External link: LegislationInland Fisheries Act 1995 and these species may not be caught or otherwise disturbed.
     
  • In particular, the Pedder galaxias (Galaxias pedderensis), swan galaxias (Galaxias fontanus), Clarence galaxias (Galaxias johnstoni), Arthurs paragalaxias (Paragalaxias mesotes), the giant freshwater lobster and two species of caddisflies are listed as endangered on the Threatened Species Protection Act 1995.
     
  • Tasmania's frog populations are under significant pressure from land use change, drought conditions that have dried aquatic ecosystems and the uncertain consequences of climate change. In response, under the Threatened Species Protection Act 1995, the green and gold frog (Litoria raniformis) has been listed as vulnerable and the striped marsh frog (Limnodynastes peroni) has been listed as rare. The green and gold frog is also listed on the International Union for Conservation of Nature (IUCN) Red List because of a drastic decline in its populations across Australia, now estimated to be more than 50% since the mid–1990s (in part due to the pathogenic fungus known as chytridiomycosis). This frog occurs in aquatic ecosystems (usually found in association with lakes, marshes, ponds and dams, either amongst sedges and other semi-aquatic vegetation or sheltering under logs and rocks) broadly across the north and east of Tasmania, on some offshore islands located in Bass Strait and in pockets in the south of the State.
     
  • Aquatic vegetation or seasonally submerged vegetation are found in areas that are either permanently or periodically under running water (lotic environments) or still water (lentic environments). These environments may be dry for some months of the year and are mainly dominated by grasses, sedges, rushes, herbs or succulent shrubs. Aquatic vegetation may also be found in areas that are inundated by tidal flow.
     
  • In 2007, there was one (4% of 23 species) extinct threatened freshwater and riparian plant, five (5% of 111 species) endangered plants and 11 (16% of 71 species) vulnerable plants identified in listing statements by the DPIW Threatened Species Section (Internal linkThreatened Species Section, DPIW 2007). Seventeen listed threatened flora species (8% of 205 species) featured significantly in listing statements for freshwater and riparian habitat types.
     
  • A habitat classification is included in the indicator for freshwater and riparian habitats. Habitat types represented in the data include coastal areas, flood zones, moist soils, damp grasslands and paper bark forests, damp forests, heath and scrub, fern gullies amidst Eucalypt forests, sheltered gullies, exposed cobbles and rock crevices. Eleven of these habitat types are identified as supporting a vulnerable threatened flora species.
     
  • Examples of threatened flora in freshwater and riparian habitats include Hooker's spleenwort (Asplenium hookerianum), Tasmanian bertya (Bertya tasmanica ssp. Tasmanica), gristle fern (Blechnum cartilagineum), Gunn's boronia (Boronia gunnii), South Esk pine (Callitris oblonga ssp. oblonga), skirted treefern (Cyathea x marcescens), small rasp fern (Doodia caudate), slender knotweed (Persicaria decipiens), roundleaf mint bush (Prostanthera rotundifolia), small leaf spyridium (Spyridium lawrencei) and clubmoss bush pea (Stonesiella selaginoides).
     
  • Twenty-one listed threatened fauna species (23% of 93 species) featured significantly in listing statements, the Threatened Fauna Handbook (Internal linkDPIW 1999) and recovery plans by the DPIW Threatened Species Section for freshwater and riparian habitat types. With respect to threatened fauna, habitat types represented in the data include ferny glades, wet vegetation types, freshwater streams, marshes and lakes, rocky shorelines, estuarine and marine environments and near island locales. Five of these habitat types are identified as supporting a vulnerable threatened fauna species.
     
  • In 2007, there were two (25% of 8 species) extinct threatened freshwater and riparian fauna species, 10 (20% of 49 species) endangered fauna species, and nine vulnerable fauna species (25% of 36 species) identified in listing statements, the Threatened Fauna Handbook (Internal linkDPIW 1999) and recovery plans by the DPIW Threatened Species Section.
     



River Reservation - at a glance

The CFEV Project (Internal linkDPIW 2008) provides an assessment of the catchment land tenure security for the 152,941 km of river network that extends across Tasmania. This assessment provides a broad indication of river catchment reservation.

  • Up to 63,294 km or 40% of Tasmania's total river length has high catchment land tenure security where there are formal regulations in place for the management and protection of freshwater riverine ecosystem values (e.g. formal reserves like National Parks, Conservation Areas and State Reserves).
     
  • A similar length of river, 61,367 km or 39% of the total river length, has low land tenure security where there are no formal regulations or mandatory restrictions in place (e.g. catchments may include areas of private land, unallocated Crown land, Commonwealth land, Hydro Tasmania managed land and/or areas managed by other water authorities).
     
  • The broad CFEV categorisation of land tenure security means there is potentially significant variation within any one category. For example, 'high' land tenure security includes National Parks and State Reserves, which differ in their restrictions resulting in rivers being subject to different levels or types of conservation or protection. Depending on the management conditions and type of restrictions, aquatic health may have greater protection in some types of reservation for rivers compared to others.
     
  • There are 48 Planning and Management Catchments in Tasmania. Five catchments have >75% of their total river length with high catchment tenure security compared to 17 catchments that have >75% of their total river length with low security.
     
  • Those with high security include the Wanderer-Giblin (nearly 100% of 6,401 km), Port Davey (99% of 9,109 km) and Gordon-Franklin (94% of 18,469 km) catchments (which lie within a Conservation Area or National Park) and the Nelson Bay (88% of 2,558 km) and Blythe (82% of 5,329 km) catchments.
     
  • Catchments that had >90% of their total river length with low catchment security include the King Island, Jordan, Clyde, Cam, Pitt Water-Coal and Macquarie catchments.
     

Statewide lake catchment land tenure security

Statewide lake catchment land tenure securityinternal SOE link to larger image

Source: Compiled by the SoE Unit using data from Internal linkCFEV database, v1.0 2005

Base topographic data provided by the LIST



Lake and Waterbody Reservation - at a glance

The CFEV Project (Internal linkDPIW 2008) conducted an assessment of the comprehensiveness, adequacy and representativeness of lakes and waterbodies in Tasmania, including their catchment land tenure security. Catchment land tenure security as it applies to lakes and waterbodies is presented in this Indicator.

  • Tasmania has 1,346 and waterbodies across Tasmania that cover a total area of 137,042 ha.
     
  • The catchment land tenure security is high for 82% of the State's lakes, although this level of security only applies to 54% of the total lake area. Formal reserves protect these lakes, with regulations that ensure the land within the lake catchments is managed to conserve or protect the landscape from potential negative impacts. Formal reserves include National Parks, Conservation Areas and State Reserves.
     
  • The higher percentage of lakes versus the area of lakes with secure catchments can be related to several large lakes with low tenure security, in comparison to many small lakes with high tenure security. This is highlighted by the Central Highlands Bioregion, which has 95% of its total number of lakes with high catchment tenure security, but 71% of the total lake area has low catchment tenure security. The Central Highlands Bioregion has several large lakes (e.g. Great Lake, Lake Echo and Lake Sorell) with catchments that are unreserved and without formal or mandatory restrictions in place to ensure conservation management and protection. These catchments may include areas of private land, unallocated Crown land, Commonwealth land, Hydro Tasmania managed land and/or areas managed by other water authorities. In contrast, there are many more smaller lakes that lie within formal reserves.
     
  • The broad CFEV categorisation of land tenure security also means there is variation within any one category. For example, 'high' land tenure security includes National Parks and State Reserves, which differ in their restrictions resulting in lakes being subject to different levels or types of conservation or protection. Depending on the management conditions and type of restrictions, aquatic health of lakes may have greater protection in some types of reservation compared to other lakes.
     
  • Overall, lake catchment tenure security is highest within the West Bioregion (84% of 119 lakes and 90% of total lake area).
     
  • Bioregions with lake catchments with the lowest overall tenure security include the Northern Midlands and King bioregions.
     
  • There are some overlaps when discussing lake and wetland reservation as it is often difficult to distinguish where a wetland finishes and a lake begins or vice versa. An assessment of wetlands is reported in the Internal linkWetlands Issue Report. The internationally recognised Ramsar sites within Tasmania are highlighted within the State and IBRA Region maps of lake catchment tenure security within this Indicator, but are discussed in detail within the Internal linkWetland Reservation and Internal linkExtent and Condition of Wetlands Iindicators.
     



Management responses

The establishment of the DPIPWE Statewide Baseline Water Quality Monitoring Program (BWQMP) has improved the coverage and availability of data on river health since the 1997 and 2003 SoE Reports. The DPIPWE network of water quantity and quality monitoring sites has been designed to provide current data on streamflow, water quality and riverine health. This assessment data will support planning and decision-making processes for water management agencies, Tasmania's three NRM regions and locally focussed catchment groups that monitor Tasmanian waterways or have an interest in water information. River and stream data collected through the BWQMP are now readily available through the External linkWaterways Monitoring Reports, which are published annually by the Water Resources Division of DPIPWE.

The development of the Tasmanian External linkConservation of Freshwater Ecosystems Values (CFEV) Project has been key to ensuring that high priority freshwater values are considered in the management of Tasmania's natural resources and incorporated into existing planning and regulatory instruments. CFEV has been developed as part of the State Government's 'Water Development Plan for Tasmania' and has also received funding through the Australian Government's 'National Action Plan for Salinity and Water Quality' (NAP), and the Australian Government Water Fund (Water Smart Australia). CFEV also created a tool that identifies important freshwater values and their conservation management priorities (both immediate and potential). The length of river and lake catchment area that is a priority for immediate conservation management in Tasmania is presented in the tables below.

River conservation management priority—immediate

Derived by considering the existing conservation value, current condition and level of management protection (land tenure security).

Category

Length (km)

Number

Length (%)

Number (%)

Very high

16,256

30,476

10.6

8.7

High

5,527

9,702

3.6

2.8

Medium

41,831

90,476

58.4

62.7

Lower

89,327

219,870

27.3

25.8

Category describes the levels of prioritisation for improving the current conservation management to protect ecosystem values within the river clusters (made up of river sections).

Source: Internal linkDPIW 2008


Lake and waterbody conservation management priority—immediate

Derived by considering the existing conservation value, current condition and level of management protection (land tenure security).

Category

Area (ha)

Number

Area (%)

Number (%)

Very high

48,230

154

35.2

11.4

High

65,378

32

47.7

2.4

Medium

16,388

354

12.0

26.3

Lower

7,046

806

5.1

59.9

Category describes the levels of prioritisation for improving the current conservation management to protect ecosystem values within the lakes and waterbodies.

Source: Internal linkDPIW 2008


In 2008, the CFEV Project released a technical report which detailed information on the assessment framework, data development and limitations. (Internal linkDPIW 2008). The report includes information on the assessment framework, data development and limitations. To compliment this report, DPIPWE is finalising a Technical Report that will outline the assessment framework and rate the conservation value and management priority of all mapped examples of freshwater ecosystems in the State.

The CFEV assessments presented in this SoE Report provide an indication of the state of rivers and lakes based on modelled data and expert knowledge collated across several years. While ground-truthing has been funded to help validate the CFEV outputs, there are still several issues and data gaps in the base data that require future review. Some of the modelled data are being validated in the field and using desktop assessments. Two projects are working together to carry out the validation:

  • Hydro Tasmania are validating data within the NRM North, NRM South and NAP regions. They are conducting both field assessment and desk-top analyses.
  • The Water Assessment Branch of DPIPWE has engaged Freshwater Systems to conduct a field-based assessment of selected data sets within key water management planning catchments.

The results of these projects will assist decision-making relating to the future update of the CFEV database.

Public access of the CFEV information is provided on the DPIPWE External linkWater Information System for Tasmania (WIST) internet link. The site also allows users to select, display and download information on streamflow, water quality and fresh water related documents. Future additions include river health, fish and water allocation modules.

A draft national framework for the identification, classification and management of Australia's High Conservation Value Aquatic Ecosystems (HCVAE) is being prepared by the Australian Government through the Aquatic Ecosystems Task Group. As part of this process a project was undertaken that reviewed existing policy, planning and legislative frameworks used to identify, classify and manage HCVAE across Australia (Internal linkSKM 2007). This included an assessment of Tasmania, which highlighted the CFEV Project as the primary tool for identifying and categorising HCVAE's in Tasmania. The project findings may be used to inform the Aquatic Ecosystems Task Group as it formulates a policy position and recommendations in relation to a national framework for managing and conserving HCVAE's (Internal linkDEWR 2007).

As part of the External linkNRM Framework established in Tasmania, the three NRM regions have developed strategies to help the long-term management of natural resources in the State including the protection of freshwater-dependent ecosystems, improving water quality and managing water use. The assessment of aquatic health in rivers through AUSRIVAS and CFEV will be complemented with the development of the Tasmanian River Condition Index (TRCI) by Natural Resource Management (NRM) groups, DPIPWE and other State and national experts. TRCI will be used to comprehensively assess river health in a holistic way with regard to the following five criteria: streamside vegetation, aquatic life, frequency and quantity of flow, channel physical form and water quality (Internal linkNRM South 2008). This new approach aims to build on and improve previous assessment methodologies such as AUSRIVAS, CFEV and IRC, and to provide information critical to monitoring, understanding and managing our rivers. The development of the TRCI is in its final stages with a report due out at the end of 2008.

There are various other management actions that have been undertaken since the 2003 SoE Report which have the potential to also influence river health in Tasmania. These management actions are detailed below. There is a vital need to build on these initiatives and those in the process of being developed.

  • Funding for the Internal linkTasmanian River Catchment Water Quality Initiative was agreed upon between the Australian and Tasmanian Governments in 2006. The overall objective of the initiative is to contribute to the assessment of chemical use on water quality in Tasmania's river catchments. It will build on baseline pesticide and herbicide monitoring that began in 2005 through DPIPWE at various river and stream sites across the State. DPIPWE's External linkPesticide Monitoring in Water Catchments forms the basis of the Internal linkWater Quality in Inland Waters: Pesticides Indicator, which is part of the Internal linkWater Quality Issue.
  • Reviewing the State Policy on Water Quality Management 1997 (Environment Division of the Environment, Parks, Heritage and the Arts (DEPHA) commenced work in 2006–07, with aim to release Discussion Paper and have findings implemented by 2008). Since this time, the Environment Protection Authority (EPA) commenced operation in Tasmania in July 2008. The EPA is part of the State's resource management and planning system (RMPS) and has been established under section 13 of the (EMPCA).
  • Tasmania signed up to the NWI in 2005, and DPIPWE has since developed a NWI Implementation Plan (Internal linkDPIW 2006) in an effort to implement efficient and sustainable water industry reforms. Some of the projects that the Tasmanian Government is progressing that aim to support the implementation of the NWI in Tasmania include reviewing the State's water legislation, implementing the outcomes from the CFEV Project, enhancing hydrological modelling and developing mechanisms for improved groundwater modelling and licensing.
  • The Water for Ecosystems Policy Framework for the identification and provision of water for ecosystems was revised in 2006 to better incorporate the suite of decision support tools that were developed since the policy came into effect in 2001.
  • At the time of writing this SoE Report, External linkEnvironmental Flow Assessment Reports had been developed for 40 rivers across the State, with some reports still needing to be finalised or subject to modification to incorporate updated methods.
  • Various past and on-going projects have been undertaken at the Tasmanian External linkWarra Long Term Ecological Research Area that include useful assessments of the effects of forestry activities on inland waters and aquatic ecosystems. Projects have examined:
    • barriers to the movement of Tasmanian freshwater fish species;
    • forestry impacts on stream fauna;
    • hydrological modelling and the hydrological effects of forestry operations on small catchments;
    • the applicability of AUSRIVAS as a Montreal Indicator in relation to water quality testing and the effects of forest management; and
    • the effectiveness of provisions within the Tasmanian Forest Practices Code 2000 to conserve and protect headwater streams.
  • New guidelines for the protection of Class 4 (headwater) streams in forestry operations have been developed by the Forest Practices Authority (FPA 2004) and they are currently being trialled by Forestry Tasmania and the Forest Practices Authority.
  • More recently, the Tasmanian River Condition Index (TRCI) has been developed by Natural Resource Management (NRM) groups, DPIPWE and other State and national experts. TRCI will be used to comprehensively assess river health in a holistic way with regard to the following five criteria: streamside vegetation, aquatic life, frequency and quantity of flow, channel physical form and water quality (Internal linkNRM South 2008). This new approach aims to build on and improve previous assessment methodologies such as AUSRIVAS, CFEV and IRC, and to provide information critical to monitoring, understanding and managing our rivers. The development of the TRCI is in its final stages with a report due out at the end of 2008. Following the final report NRM groups and DPIPWE will determine what aspects of the assessmemnt methodology they will adopt as part of their work programs. According to the April 2008 NRM South newsletter Naturally Inspired, as part of the assessment, 'current condition will be compared to pre-European condition, with re-assessment occurring at regular intervals ... while defining pre-European condition has presented challenges in similar assessments interstate, TRCI will incorporate a number of innovative methods.'

Water Management Act 1999 and Water Management Plans

The External link: LegislationWater Management Act 1999 is the principal legislation regulating the management of Tasmania's water resources including water extraction and storage. A review of the Act began in 2005, which included public submissions (to help identify measures to improve the operation of the Act) and a report from DPIW in response to these submissions (e.g. Internal linkDPIW 2006). DPIW identified four mechanisms through which the findings of the review could be progressed. Some of the following mechanisms have begun to be implemented:

  • Tasmania's implementation of the National Water Initiative (NWI) Agreement;
  • legislative amendments to the External link: LegislationWater Management Act 1999 (Dam Works Legislation (Miscellaneous Amendments) Act 2007, Water Legislation Amendment Bill 2008 to be debated in spring session of 2008 Parliament and later amendments to both the Waterworks Clauses Act 1952 and Irrigation Clauses Act 1973);
  • procedural changes to administrative processes used by the Water Resources Division of DPIW; and
  • a review of the State Policy on Water Quality Management 1997 to be undertaken by the Environment Division in the Environment, Parks, Heritage and the Arts (DEPHA).

The External link: LegislationWater Management Act 1999 provides for the development of Water Management Plans, which are designed to ensure the sustainable development and management of Tasmania's water resource. To date, plans have been prepared for five catchments, namely: Little Swanport, Great Forester, Mersey, River Clyde and Lakes Sorell and Crescent. At the time of writing work is underway on the Management Plan for the South Esk.

Generic Principles for Water Management Planning (Internal linkDPIW 2005) have been developed by DPIW in recognition of the need to accelerate the development of Water Management Plans to ensure greater certainty in protecting the State's water resources and providing access to water to users. Hydro Tasmania's Water Management Review (WMR) Program is also designed to complement the Water Management Plan requirements.

Related issues

WaterInternal link

Catchment Land Use Activities

Coasts and Estuaries Water Quality

  External linkTasmanian Planning Commissioninternal SOE link to larger image

  Contact the Commission on:

email: External linksoe@justice.tas.gov.au
Phone: (03) 6233 2795 (within Australia)
Fax: (03) 6233 5400 (within Australia)
Or mail to: Tasmanian Planning Commission, GPO Box 1691, Hobart, TAS, 7001, Australia

 


Last Modified: 1 Mar 2010
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