Background

Implications

Regional aspects

Assessing and measuring the current situation

Indicators

Management responses

Discussion

Future directions

Related issues

Background

One of the most significant threats to natural diversity in Tasmania is the clearing of native vegetation and its replacement with another activity (e.g. tree farms, agriculture, dams etc). The impacts of land clearing depend on the disturbance intensity and frequency, and the spatial context of the disturbance. The types of land clearing can be viewed along a continuum, in relation to the level of impact upon biodiversity. At one end of the continuum is 'reversible clearance' and 'irreversible clearance' lies at the other end. The greater is the intensity, frequency and area of disturbance with the removal of native vegetation, the more irreversible the activity and therefore, the greater the risk of flora and flora extinction. Relatively small losses in vegetation communities that are already significantly depleted are of immediate concern. In contrast, nature conservation impact is lessened where clearance occurs in vegetation types that are well-reserved and relatively little depleted.

It is now widely accepted that the long-term maintenance of ecosystem health and, by implication, productive systems depends on the maintenance of native vegetation cover. In a recent publication a figure of 30% cover has been nominated as the minimum lower limit of native vegetation cover (Williams 2000).

Between 1972 and 1999 over a quarter of a million hectares of native vegetation were cleared in Tasmania. The amount of native vegetation approved for conversion to plantation or non-forest use between 1999-2000 was 15,820 ha, between 2000-2001 was 13,450 ha, and between 2001-2002 was 9,280 ha (Forest Practices Board 2000, 2001, and 2002).

Historically, the greatest losses of major vegetation types have been in swamp forests, grasslands and grassy woodlands, coastal heathlands, dry forests and wetlands. The most threatened community types now are the grasslands and grassy woodlands. The least affected types since 1803 appear to be less agriculturally productive, such as alpine vegetation, and western moorland and scrub.

Brief history of land clearance in Tasmania

Modification of land cover began with the Aborigines who used fire to reduce woody vegetation and create open plains, which favoured game and edible plants. The arrival of Europeans and their technology heralded a huge leap in capacity to clear vegetation. Since European settlement in 1803 it has been calculated that 23% or 1.560 million hectares (CARSAG APU data 2002) of Tasmania has been cleared.

The majority of Tasmania is mountainous, with plains suitable for agriculture found only in the north-east, Midlands, central highlands and the far north-west. Natural vegetation on agriculturally desirable soils in valleys (e.g. Derwent and Huon), the Midlands and the north-west coast was cleared in the first few decades of the nineteenth century. Pulses of vegetation clearance followed the ends of the two World Wars, with the promotion of soldier settlement schemes, and the advent of the export woodchip industry in 1971.

The key drivers of land clearance in Tasmania have changed over time. The grassy woodlands of the State are ideal for producing fine wool. In the late 1960s to early 1970s a rise in commodity prices for fine wool became a driver for clearing to expand pasture and for the use of woodlands and dry forest areas for grazing.

In the 1970s and 1980s, significant clearance of native vegetation occurred for agricultural purposes. Most conversion of forest to pasture occurred along margins of already cleared land or in remnant patches of native vegetation. Clearing was concentrated in dry eucalypt forests in the east and north-east of the State. There was also some clearing resulting from inundation through hydro-electric impoundments (AGO 2000).

In the mid 1970s to late 1980s conversion from broadscale sheep and beef enterprises to more intensive dairy farming took place and involved some clearing to expand existing pasture, particularly in the north-west of the State (AGO 2000). The pattern of land clearance shifted from the drier parts of Tasmania towards the moister areas, and from the centre of the State towards the extremities. The nature conservation impact of land clearance decreased from the 1970s and 80s, as the highest rates of clearance shifted from vegetation types of high conservation value to those that are well-reserved and relatively little depleted.

In more recent years (particularly in the period since the last SoE Report), conversion to plantation has become a more significant driver of land clearance in Tasmania. Vegetation types of conservation significance continue to be cleared, although action recently taken to cease clearance of threatened forest and non- forest communities will mean that this should reduce to negligible levels for these communities in the future. Clearing in other communities may continue to be substantial depending on market forces and the final terms of the Permanent Forest Estate.

Through the RFA the State Government developed a Permanent Forest Estate Policy. The policy sets a minimum threshold percentage that must be retained and below which forest vegetation cannot be cleared. All forested land in Tasmania has been classified according to the type of forest community it contains (e.g. white gum grassy forest), where it occurs in the State (e.g. Midlands region), and how much existed in 1996. The minimum thresholds are set for three levels: State, regional (e.g. IBRA) and forest community. The Statewide threshold is 80% and at least 50% of the native forest present in each region in 1996 must be retained. The percentage of each forest community that must be retained varies from 60-80% though in some small or threatened communities 100% of the community must be retained. The Regional Forest Agreement (1997) also resulted in the creation of an additional 458,000 ha of new reserves containing 293,000 ha of forest (RPDC 2002)

The motivators for land clearance in Tasmania are more comprehensively described in the National Carbon Accounting System Technical Report: Land Clearing: A Social History (AGO 2000).

The Background report for the 2002 RFA review (RPDC 2002) documents current initiatives to retain native vegetation.

Implications

• The most significant threat to natural diversity in Tasmania is the clearing of native vegetation and its replacement with another activity (e.g. tree farms, agriculture, dams, housing etc).
   
• Vegetation clearing is the major threat to biodiversity and may cause species extinctions by reducing and fragmenting available habitat.
   
• Potential loss to eco-tourism opportunities.
   
• Land clearance impacts landscape aesthetics as it leads to changes in the visual landscape.
   
• Clearing of native vegetation may also lead to changes in ecosystem processes. These changes depend on what the native vegetation is converted to, but may include: less rainfall intercepted by vegetation; increased erosion; increased temperatures close to the ground; and more rapid loss of soil moisture. Through these processes, the environmental impact on remaining vegetation may be accumulative. The Tolmans Hill subdivision case study illustrates the processes contributing to accumulative losses of bushland.
   

Regional aspects

There is variation across Tasmania in the principal drivers of land clearance and the rates of land clearance. For example, in the south-east around Hobart, clearance associated with subdivision is a more significant contributor. Negligible rates of land clearance occur in the west and south-west, although there are still some agents of land cover change occurring in these areas such as erosion of peatlands. Historically, inundation caused by hydro-electric impoundments affected areas in the south-west. Between 1997 and 2001 the bioregions of Woolnorth in the north-west and Ben Lomond in the north-east of Tasmania experienced the greatest amount of land clearance on public and private land.

Assessing and measuring the current situation

There is no single data source to report on land clearance and vegetation change in a systematic and consistent way for different land uses, vegetation types and tenures. Forest Practices Board data is used to provide a guide to forestry related clearance. However, this does not include all conversion of native forest directly to other non-forestry related land uses such as conversion to pasture. Clearance of vegetation communities for other uses such as housing is also not measured or reported. Measures of vegetation change for non-forest vegetation communities are comparatively less well studied or reported. The estimates provided in the indicators below reflect these data limitations.

Indicators

Native Vegetation Clearing - at a glance

• Continued in depth

Clearing rates for State

The total extent of native vegetation cleared in Tasmania since European settlement in 1803 has been calculated to be around 23%, or 1.560 million hectares (CARSAG APU data 2002). The table below provides recent estimates from a range of sources on Statewide clearance rates.

Estimates of native vegetation clearing rates in Tasmania, 1972-00

Period	Clearing rates (ha/year)	Total cleared (ha)	Data source	Details of methodology
1972-80	18,725	149,800	Kirkpatrick and Dickenson (1982)	Satellite imagery*
1980-88	6,000	48,000	Kirkpatrick (1991)	Satellite imagery*
1988-94	10,429	62,574	Kirkpatrick and Jenkin (1995)	Satellite imagery*
1994-99	6,992	34,960	Kirkpatrick and Mendel (1999)	Satellite imagery*
1988-98	7,770	77,700	AGO 2002	Satellite imagery

* these studies include areas that have been converted from native forest to one of the following land uses: agriculture, plantations and hydroelectric impoundments (i.e. dam construction).

Clearing rates for bioregions

Vegetation clearing rates available bioregionally are those provided by the Forest Practices Board. Woody change data from Landsat remote sensing provides another perspective, which is included in the indicator in detail. There are significant differences between Forest Practices Board and Landsat change analysis and the latter requires further analysis before it can provide a truer perspective on bioregional vegetation change.

From Forest Practices Board data, the highest rates of clearance on public and private land occurred on the Woolnorth (north-west) and Ben Lomond (north-east) bioregions. In the period, 1997-01, 19.782 ha were approved for clearance in the Woolnorth bioregion and 18,992 ha were approved for clearance in the Ben Lomond bioregion.

Clearance by vegetation type

On a Statewide basis, four of the RFA forest community types with the greatest amount of clearing (not including native forest areas that have been clearfelled and regenerated from native seed) since 1997 include:

• Tall brown-top stringybark (Eucalyptus obliqua) forest, which lost almost 5% (20,109 ha) of its 1996 RFA area;
   
• Swamp gum (E. regnans) forest, which lost almost 12% (9,040 ha) of its 1996 cover;
   
• Wet white gum (E. viminalis) forest on basalt lost 7.4% (308 ha) of its 1996 cover; and
   
• White gum (E. viminalis)/black gum (E. ovata)/black peppermint (E.amygdalina)/brown-top stringybark (E. obliqua) damp sclerophyll (hard-leaved) forest community lost 7.2% (2,916 ha) of its 1996 cover.
   

Between 1 July 1997 and 30 June 2001, 62,831 ha was approved for clearing (mainly for plantation and agriculture).

Proportion of vegetation clearance in each bioregion and catchment

• In 1999 three bioregions had below 10% of their areas cleared, including the West, Central Highlands and Southern Ranges bioregions. The Ben Lomond bioregion had only 18.3% cleared.
   
• The six remaining bioregions each had greater than 30% of their area cleared.
   
• The data indicates that as of 1999 the catchments least disturbed (less than 20% of their area) by land clearance are those in western and south-western Tasmania, and to a lesser extent parts of eastern Tasmania north of Swansea.
   
• The most disturbed catchments indicated in 1999 are those in areas of major agricultural development in the Northern Midlands and north-west coast.
   
• The indicator calculated excludes King Island (lack of data) and does not take into account lakes and artificial water impoundments. That is, for simplicity the data from the bioregion and catchment maps and the vegetation clearance layer were analysed as if the water bodies did not exist (neither data set recognises the presence of water bodies). Natural water bodies arguably should not be included in figures for 'uncleared' vegetation, whilst artificial impoundments arguably constitute areas of 'cleared' vegetation. The difference in figures obtained may be small in some catchments, but is likely to be significant in catchments such as the Gordon, Pieman, Mersey, Derwent and others that include large natural and/or artificial water bodies.
   

Land Cover - at a glance

• Continued in depth

• The long-term maintenance of ecosystem health, and by implication, productive systems is dependent on the maintenance of native vegetation cover. The area modified and the level of woody vegetation change within bioregions across Tasmania provides an indication of land cover changes including native vegetation changes.
   
• The analysis of woody vegetation change compares woody vegetation cover from Landsat satellite images from ~1994 with images from ~2001. The on-the-ground context in which these changes are occurring is all important: not all woody vegetation loss may be 'bad' for the environment and not all woody gains may necessarily be 'good'.
   
• The woody vegetation decrease on private property was 10,858 ha per annum in the period 1994-01. Woody vegetation decreases relating to agriculture or pasture were identified from the land cover classification. The woody vegetation loss of 20,617 ha on agricultural land (2,945 ha per annum) in the period 1994-01 was comparable with the figure of 2,879 ha per annum identified by Kirkpatrick and Mendel 1999 for the period 1994-99.
   
• Some data limitations were evident. Overlays of the woody vegetation decrease with TASVEG data showed that a proportion of the vegetation loss occurred on agricultural land that may have already been largely cleared of native vegetation. For example, some crops-such as poppies-give a similar spectral signature to woody vegetation, and the harvesting of these crops may be identified as a woody vegetation loss. Nevertheless, a percentage of the woody vegetation decrease on agricultural land would relate to clearance of native vegetation.
   

Area of Plantations - at a glance

• Continued in depth

Much plantation development in Tasmania is on already cleared land. Key general trends in plantation development include the following:

• Rapid expansion in eucalypt plantation establishment during 1996-2001 increasing in area by 60% or 44,000 ha (Forest Practices Board 2002).
• An increase of 11,900 ha in the area of softwood plantation (Forest Practices Board 2002).
• The largest percentage area of plantation development occurs in the Ben Lomond and Northern Slopes Bioregions, which contain 57,913 ha of softwood and hardwood plantations (8.8% of the area of the bioregion) and 69,706 ha (11.2% of the area of the bioregion), respectively.

Terrestrial Protected Areas - at a glance

• Continued in depth

• The RFA has helped to improve the representativeness of the reserve system for forests in Tasmania. The Comprehensive, Adequate and Representative (CAR) forest reserve system has resulted in the creation of an additional 458,000 ha of new reserves containing 293,000 ha of forest (RPDC 2002).
   
• The Private Forests Reserve Program is responding to the need to protect the many species and communities that do not occur on public reserved land. Conservation initiatives on private land is especially important in the eastern, central and northern parts of the State where land clearing in particular has been greatest.
   
• Six of the nine bioregions in Tasmania have more than 80% of their area outside of any type of reserve. The situation is particularly critical in the Northern Midlands region where 97.4% of the region is outside any type of public or private reserve. Less than 3% of the Northern Midlands region is contained within any type of reserve.
   

Management responses

• The Regional Forest Agreement (Government of Tasmania and Commonwealth Government 1997) developed a Permanent Forest Estate Policy. The policy sets out a minimum threshold percentage that must be retained and below which forest vegetation cannot be cleared for commercial forestry. It has helped to improve the representativeness of the reserve system for forests in Tasmania. A review of the Regional Forest Agreement has been completed (RPDC 2002).
   
• The Permanent forest estate policy is currently under review. The review is addressing the current vegetation retention thresholds, both the total threshold and the individual thresholds for different forest communities. A program of consultations is underway with the Tasmanian Farmers and Graziers Association and other key stakeholders, including forestry interests, the Tasmanian Conservation Trust and the Local Government Association of Tasmania to develop mechanisms for managing native non-forest vegetation on private land. It is expected that the mechanisms will focus on the preparation and accreditation of property-based plans.
   
• In April 2001, land clearance was listed as a threatening process under the Environment Protection and Biodiversity Conservation Act 1999.
   
• The Vegetation Management Policy Framework was announced by the State Government in July 2001. Under the framework the Forest Practices Amendment Act 2001 was enacted to require permits for the clearance of forest, irrespective of the purpose of clearance. These provisions apply where the area to be cleared is more than 1 ha per year or greater than 100 tonnes per year. The Vegetation Management Policy emphasises co-operative approaches with landholders.
   
• The Forest Practices Board introduced a moratorium on the conversion of Rare and Endangered forest communities.
   
• The State Government announced in May 2003 that all Rare, Endangered and Vulnerable forest communities would now be protected using the Forest Practices System. The new measures will prevent the clearing of 107,000 hectares of Rare, Endangered and Vulnerable forest communities on private land in Tasmania. This includes grasslands, heath and scrub. Councils would play an important role through their planning schemes by taking account of at risk non-forest vegetation communities when considering developments.
   
• The definition of vulnerable land under the Forest Practices Regulations 1997 is also to be amended to protect areas set aside under previous forest practices plans, for example as riparian reserves.
   
• The Department of Primary Industries, Water and Environment established a Private Forest Reserves Program in July 1998 to promote the system of CAR forest reserves on private land in Tasmania. It is responding to the need to protect the many species and communities that do not occur on public reserved land. Conservation initiatives on private land are especially important in the eastern, central and northern parts of the State where land clearing in particular has been greatest.
   
• Tasmania has, with Natural Heritage Trust assistance, developed a Protected Areas on Private Land Program. With landholder approval, areas of non-forest conservation significance as well as forested areas that do not meet the priorities of the Private Forest Reserve Program are covenanted. Land Tax relief and rate rebates are available in some municipalities as incentives.
   
• Incentive programs funded by the Natural Heritage Trust to fence off and manage riparian areas have been introduced. Funds for riparian vegetation management are available under Rivercare, Bushcare and Regional Natural Resource Management strategies, primarily through devolved grant schemes.
   

Discussion

Future directions

Some examples of areas in which progress is needed include the following:

• Improve capacity for vegetation change detection, allowing changes to be identified with both tabular and mapped based outputs showing vegetation communities affected and conservation status of these communities. Enhanced vegetation change detection capacity to be coordinated through a single entity where data and methods are assessed and amalgamated.
   
• Undertake a 'whole-of-landscape' approach for the assessment and planning approval process of land clearance, where the disturbance intensity and frequency and the spatial (e.g. bioregion or catchment) context are considered
   
• Establish integrated approaches between biodiversity and land management objectives. In particular, vegetation removal is the primary cause of rising water tables, which in turn is the primary process responsible for the development of dryland and agricultural salinity. A moratorium on tree removal throughout catchments in the Midlands, southern and central East Coast, Derwent Valley, Coal River Valley and other salinised areas should be considered (Dell 2000). Such a moratorium could be undertaken in a manner to achieve both nature conservation and land management benefits.
   
• Improve processes for the assessment and approval of the conversion of non-forest vegetation.
   
• Maintain and extend where possible existing programs that have had success in protecting priority vegetation communities, in particular the program
   

Tasmania Together and the RMPS

Relevant Tasmania Together goals and standards for 'Biodiversity' are listed in the linked file. The Tasmania Together Progress Board reported on progress toward targets for benchmarks set (Tasmania Together Progress Board 2003). Indicators, targets and baseline data are available in the latest Progress Report June 2003. Further information, including progress report updates, is available from Tasmania Together.

Involvement of the community, and the fair and orderly use of resources are also fundamental principles of the RMPS. The RMPS objectives have been developed to advance the principles of sustainable development.

Related issues