Biodiversity & Vegetation - Tasmania

Proportion of native vegetation remaining in this IBRA region Tasmania
Methods
Applications
Limitations
What major vegetation groups have been cleared in Tasmania since European settlement?
Methods
Applications
Limitations
Link to cleared native vegetation information for Tasmania's bioregions
What sources of information were used?
References
Partnerships
Further information

Tasmania

Proportion of native vegetation remaining in Tasmania

In Tasmania 16% or 1.0 million hectares of the native vegetation has been removed, mainly in the lowlands of the north west, midlands and the south east of the island as well as Flinders and King Islands. The most affected major vegetation groups are the eucalypt open forests, eucalypt woodlands and eucalypt tall open forests.

This is an overestimate of intact native vegetation, in particular forested vegetation groups, as further clearing has occurred since much of the mapping was undertaken. More recent extent figures summarised by subregions are presented in the Audit Landscape Health in Australia report (NLWRA 2001c).

This assessment of landscape health provides a summary on a subregional basis of the landscape stresses in Tasmania including clearing, grazing, feral animals and weeds.

Table: Area (km²) of pre-European major vegetation groups and major vegetation groups (circa 1997) in Tasmania
Major Vegetation Group	Pre-European Area (km²)	Circa 1997 Area (km²)	% remaining relative to pre-European area
Rainforest and vine thickets	7,161	7,055	99
Eucalyptus tall open forests	8,540	6,193	73
Eucalyptus open forest	23,627	19,212	81
Eucalyptus low open forest	217	106	49
Eucalyptus woodlands	7,181	4,609	64
Acacia forest and woodlands	194	28	15
Callitris forest and woodlands	1	1	88
Casuarina forest and woodlands	167	156	93
Other forests and woodlands	359	359	100
Eucalyptus open woodlands	1,251	1,108	89
Low closed forest and closed shrublands	2,843	2,168	76
Acacia shrublands	14	13	98
Other Shrublands	788	755	96
Heath	1,926	1,925	100
Tussock grasslands	1,109	1,090	98
Other grasslands, herblands, sedgelands and rushlands	10,678	10,670	100
Chenopod shrub, samphire shrub and forblands	28	28	100
Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes	1,880	1,880	100

Methods

This analysis is based on a comparison of the present extent of major vegetation groups (circa 1997) and pre-European mapping.

Applications

Analysis at the Australia-wide, State and Territory and regional scales provides information on which to base broad assessments of change in extent and type of vegetation. This is a key input to assessing:

the representativeness or otherwise of Australia's nature conservation estate and for related interpretations (e.g. setting priorities for retention of native vegetation types);
opportunities for catchment rehabilitation, whether the issue is catchment hydrology or dryland salinity control;
the types of vegetation suitable for rehabilitation, restoration and/or revegetation activities in an area; and
priorities for protection of biodiversity in landscapes under stress.

Limitations

Pre-European vegetation and present native vegetation for many States and Territories do not match in mapping method or scale. Development of pre-European vegetation maps in cleared areas of Australia is usually dependent upon coarse or generalised data on landforms and soils sometimes at 1:250 000 or even 1:1 000 000 scale. Reconstructing the natural complexity of vegetation patterns from such broad interpretations is difficult. Earlier vegetation mapping for areas now cleared may similarly be coarse in scale and/or generalised, with little data from systematic field sampling to support the derivation of mapping units and the allocation of individual patches of native vegetation to mapping units.

Pre-European data is more reliable where:

impacts of European land use is minimal;
there is good physical and floristic information (e.g. in Victoria) which can be used for detailed interpolation; and
the scale of the pre-European mapping and method is similar to that of the current extent mapping (e.g. in Queensland, Victoria, Northern Territory and Western Australia).

Data variability is greatest in New South Wales, the Australian Capital Territory and South Australia, where the pre-European data does not meet the requirements of the National Vegetation Information System. In Tasmania the pre-European data is not finalised. In these States it is assumed that the present vegetation mapped is an approximate representation of the pre-European vegetation. The Australia wide pre-European major vegetation groups data set is an interim product.

What major vegetation groups have been cleared in Tasmania since European settlement?

Table: Major vegetation groups cleared in Tasmania
Major Vegetation Group	Cleared Area (km²)	% cleared across TAS as total of clearing
Rainforest and vine thickets	105	1
Eucalyptus tall open forests	2,346	21.9
Eucalyptus open forest	4,415	41.3
Eucalyptus low open forest	110	1
Eucalyptus woodlands	2,572	24.1
Acacia forest and woodlands	166	1.6
Casuarina forest and woodlands	11	.1
Eucalyptus open woodlands	143	1.3
Low closed forest and closed shrublands	675	6.3
Other Shrublands	33	.3
Heath	1	0
Tussock grasslands	19	.2
Other grasslands, herblands, sedgelands and rushlands	8	.1

Note: The clearing referred to in table 2 does not include grazing, thinning or other activities. In particular, parts of the rangelands may be heavily disturbed.

Map: Cleared Major Vegetation Groups (circa 1997) in Tasmania

Cleared Major Vegetaion Groups in Australia

Source:

Major vegetation groups V1.0 (1km), National Land and Water Resources Audit 2001. Data used are assumed to be correct from suppliers.

The summary maps provide information on Australia's native vegetation collated within the National Vegetation Information System (NVIS) at July 2001 and with additional mapped information. The NVIS will be updated as vegetation mapping becomes available.

The map is a compilation of data collected at different scales by different organisations. Major Vegetation Groups were compiled by Environment Australia based on data collated by the Bureau of Rural Sciences and provided by Environment ACT, Department of Urban Services; NSW National Parks and Wildlife Service; NSW Royal Botanic Gardens; NSW State Forests; NT Department of Infrastructure, Planning and Environment; Queensland Herbarium, Environmental Protection Agency; SA Department for Environment and Heritage; Tasmanian Department of Primary Industries, Water and Environment; Flora Section, Department of Natural Resources and Environment; Agriculture Western Australia; Western Australia Department of Conservation and Land Management and Geoscience Australia, National Mapping Division.

Methods

This analysis is based on the present extent of native vegetation and data on the type and area of these groups cleared in Australia from the pre-European mapping. All summary findings are based on the data sets compiled for the National Vegetation Information System and development of the major vegetation groups.

Applications

This analysis at the Australia-wide, State and Territory and regional scales provides information on which to base assessment of change in land cover and type of vegetation, a key input to vegetation management activities. Loss of particular vegetation types across regions impacts on biodiversity values and landscape function and this analysis highlights those major vegetation groups.

At the regional scale, the National Vegetation Information System compilation provides an excellent basis for regional planning groups to understand the changes in vegetation extent that have occurred and set their regional priorities for vegetation management in the context of this information. The assessment of major vegetation groups across Australia provides a broader context.

Limitations

As detailed previously, issues of attributes, scale and currency of available mapping limits the precision of this analysis. The broad nature of the major vegetation groups masks the distinct vegetation types and regional clearing patterns that would emerge at a finer scale of analysis.

Link to cleared native vegetation information for Tasmania's bioregions

Map of cleared native vegetation information for Australia's bioregions

What sources of information were used?

View the guidelines for the interpretation of vegetation mapping products.

References

View the references used in the Australian Native Vegetation Assessment 2001.

Partnerships

Australian Native Vegetation Assessment 2001 was facilitated and coordinated by the National Land and Water Resources Audit and prepared in partnership with State, Territory and Commonwealth agencies: