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In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Australian Native Vegetation Assessment 2001
Maria Cofinas, Colin Creighton
National Land and Water Resources Audit, 2001
ISBN 0 642 37128 8
National Vegetation Information System
Photo: Maria Cofinas
The framework supporting the Australian Native Vegetation Assessment 2001
The National Vegetation Information System framework (NLWRA 2000a) provides an easily accessible and nationally consistent framework for describing and compiling data and information all vegetation types in Australia. Its application and adoption means that Australia has a robust and flexible system for collecting, compiling, analysing and reporting on vegetation information from regional to national levels.
The framework specifies guidelines to describe:
- structural and floristic characteristics of the vegetation for mapped areas and individual sites;
- data quality;
- sources of vegetation information collected in Australia; and
- vegetation condition.
As the basis for collaborative and collective work across Australia, the National Vegetation Information System was designed to meet an agreed set of guiding principles. These principles were established as part of the initial scoping of the tasks and provide an excellent frame of reference for continued cooperative development.
National Vegetation Information System guiding principles
- resolving data and information differences across administrative and program boundaries to provide comparable and consistent information Australia wide
- collaborative work of mutual benefit
- recognising regional level environmental differences
- flexible and extendable
- fully documented quality and application of the component data sets
- delivering information to meet current needs, foreshadowing and anticipating long-term needs
- improving the knowledge and information base of Australia's vegetation (pre-European and present) and addressing data gaps
- ensuring use is commensurate with data
- providing information and assessments to support vegetation and other natural resource management decision making
- improving data access and dissemination
- recognising the jurisdictional role in meeting specific vegetation information requirements, management responsibilities and obligations
The hierarchical approach to classifying Australia's native vegetation
The National Vegetation Information System information framework defines a hierarchical classification system for describing the structural and floristic patterns of groups of plants in the landscape (NLWRA 2000a). Collectively, the different levels in the classification provide a description of vegetation that can be directly related to precise spatial areas as a vegetation map.
This system benefits data collection and use by:
- standardising the level of detail within a data set, and within and between jurisdictions;
- enabling existing and new vegetation data and information to be described;
- facilitating the addition of new levels of data for particular applications (e.g. forestry);
- providing a flexible framework for generating outputs such as map products at various levels; and
- providing users with a range of vegetation descriptions for various applications.
The hierarchy is based on six levels (Table 1, Figure 3), presenting broad vegetation classifications at national scales (Levels I-III) to a detailed level of information for users at regional scales (Levels IV-VI).
Supporting this hierarchy are a series of attributes (NLWRA 2000a) that can be summarised to report on the hierarchy or combined in other ways to develop user-based classifications of vegetation.
| Hierarchical level | Description | National Vegetation Information System structural/floristic components required |
|---|---|---|
| I | Class | Dominant growth form of the ecologically dominant stratum. |
| II | Structural formation | Dominant growth form, cover and height of the ecologically dominant stratum |
| III | Broad floristic formation | Dominant growth form, cover and height of the ecologically dominant stratum |
| IV | Sub- formation | Dominant growth form, cover, height and broad floristic code usually dominant genus and family of the three traditional strata (i.e. upper, mid and ground) |
| V | Association | Dominant growth form, height, cover and species (three species) of the three traditional strata (i.e. upper, mid and ground). |
| VI | Sub- association | Dominant growth form, height, cover and species (five species) of all layers/strata. |
National Vegetation Information System hierachy definition
Dominant
A characteristic of a species that has the greatest possible influence in the vegetation type being described.
Ecologically dominant stratum
The stratum, which because of its physiognomy and relative continuity, dominates the rest of the vegetation type in the sense that it conditions the habitats of other strata (Beadle & Costin 1952).
A series of decision rules about the height and foliage cover of the vegetation can assist with assigning the ecologically dominant stratum in a vegetation type. The consistent assignment of this is important to ensure compatibility of vegetation information across data sets.
These decision rules become important when existing vegetation mapping standards have defined dominance in different ways (e.g. the Beard-Webb versus the Specht systems). Classifications begin to vary considerably (e.g. when considering vegetation types as shrublands and grasslands with very sparse emergent trees: by the Specht scheme these would be classed as open woodlands whereas by the Beard-Webb Scheme they are classed as shrublands or grasslands).
Growth form
Habit of a plant, identified most precisely by the position of its perennating buds (e.g. tree, mallee, shrub) (Beadle & Costin 1952).
Stratum
Layer in a vegetation type produced by the occurrence (at approximately the same level) of an aggregation of plants of the same habit (Beadle & Costin 1952).
Cover
Cover produced by the foliage of any vegetation within a defined area.
Height
Measurement from the base to the top. Can be calculated for a given vegetation type to derive the average height for a given stratum.
Broad floristic
Usually the genus of the dominant species in the dominant stratum.
A combination of growth form, height and cover is used to describe the vegetation structure for each stratum for levels II to VI. A description of the height class then allows for a more common structural description of the vegetation (e.g. low open woodland has a tree growth form with a height class of less than 10 m and less than 10% foliage cover). Appendix 7 includes the information used to derive this description.
The Australian Vegetation Attributes (NLWRA 2000a) provide consistent definitions and guidelines that were used by the lead agencies in each State and Territory to translate and compile a selection of existing native vegetation data sets. Using the attributes, information can be compiled on:
- the mapped data set (e.g. mapping methods and attribute accuracy) which may assist in an assessment of its reliability for a particular use;
- the dominant vegetation within a mapped unit and information on its strata, growth forms and species; and
- other co-dominant or subdominant vegetation types within a mapped unit and information on the strata, growth forms and species.
Appendix 5 lists all the vegetation attributes and the definition of each attribute is available in the Australian Vegetation Attributes (NLWRA 2000a).
Relationships between the attributes are complex and comprehensive and describe the range of vegetation layers (strata), growth forms and species descriptions required for a detailed vegetation description for all components of a mapped unit. They allow for multiple descriptions of vegetation types within a mapped unit, often referred to as mosaics of vegetation.
Figure 2 shows one map unit for a South Australian data set. This map unit is a vegetation mosaic with two vegetation descriptions. All available levels of information are presented for vegetation description 1.
Vegetation description 1 has three strata:
- Stratum 1 has one growth form and one taxon description
- Stratum 2 has two growth forms and two taxon descriptions
- Stratum 3 has five growth forms and five taxon descriptions
As an example, the data set description and all attributes related to vegetation description 1 as entered into the National Vegetation Information System database are found in Appendix 6. The Australian Vegetation Attributes (NLWRA 2000a) should be used in association with this table for a definition of these attributes and units of measurement.
Figure 3. Hierarchy information as a map legend for a small number of polygons (Brigalow Belt North bioregion, Queensland).
See Glossary for additional terms in legend
Ensuring quality in the National Vegetation Information System
Minimum requirements for the National Vegetation Information System were developed as part of the framework for data compilation. They were then implemented as part of data collation. Some key requirements include scale, currency of mapping and attribute detail.
Scale
Two scale thresholds are needed for current and future native vegetation mapping: 1:100,000 scale or finer mapping in the intensive land use zone, and 1:250,000 scale mapping or finer in the extensive land use zone (Figure 4).
Figure 4. Intensive and extensive land use zones of Australia.
These thresholds also define the scale of data sets required for regional planning and management: greater detail is required in areas with intensive land use and clearing. Within these areas the majority of the decisions relating to natural resource and environmental management are made. They include key areas for biodiversity loss, dryland salinity, soil erosion, urban expansion and degradation to key ecosystems such as rivers and estuaries.
As a general rule, less detail and precision is required for vegetation information in the extensive land use zone either because there have been fewer human impacts or the areas are remote and not used. This extensive use zone broadly conforms with that part of Australia known as rangelands. Through the rangelands theme, the Audit has recommended a specific set of monitoring activities that build upon the scale of vegetation mapping, are compliant with National Vegetation Information System guidelines and will provide key information for the natural resource management for these lands.
For pre-European vegetation mapping 1:1,000,000 scale data was recommended as a suitable scale for broad assessments across Australia. This recognises that, compared with current vegetation mapping, relatively little spatial detail is available or possible for pre-European vegetation types.
Helipterum albicans, Tetratheca spp: Brindabella Ranges
Photo: Murray Fagg
Currency
Currency of present vegetation mapping compiled in the National Vegetation Information System was specified to a minimum of 1997 for undertaking a year 2000 data compilation exercise. This applies equally to maps (spatial units) and associated attributes. Application of this threshold is flexible and depends on rate of land use change for a region (e.g. preferably a region undergoing rapid changes to the native vegetation should have its vegetation information updated on an annual or biannual basis to ensure change is monitored and the community kept up-to-date with major issues such as the extent of clearing and location and size of areas of remnant vegetation).
Attributes
Level V (vegetation association) of the National Vegetation Information System hierarchy was specified as the target for incorporating native vegetation data into the National Vegetation Information System. The Level V target defines the detail required by decision makers such as those involved in regional planning and management.
The Australian Vegetation Attributes, Version 5.0 (NLWRA 2000a) identified 81 mandatory attributes to be compiled for each data set. Mandatory attributes were grouped into four categories:
Ma: Mandatory required for National Vegetation Information System hierarchy
Mb: Mandatory required for data quality
Mc: Other essential information required to define a data set
Md: National attributes (e.g. National Vegetation Information System identification)
Implementing the National Vegetation Information System
Data compilation
Guidelines for classifying Australia's vegetation were agreed and potential sources of vegetation mapping for inclusion in the data collation program were documented. Each State and Territory nominated vegetation maps to be used, preferably those that met minimum requirements of the National Vegetation Information System. Where mapping was unable to comply with standards but otherwise provided an important coverage of part of a State, the best available mapped information was provided as 'interim coverage'.
State and Territory compilation activities were supported by expert advice on translation and interpretation of vegetation mapping and on information products required by decision makers.
Activities were constrained by available financial resources and time frames. Time frames were extended by a year beyond that specified in the Audit strategic plan, doubling the actual resources dedicated to the initiative. Data sets incorporated into the National Vegetation Information System are summarised in Appendix 8; methods used to implement the various components of the framework are documented in Appendix 9.
Great Cumbung Swamp
Photo: Murray-Darling Basin Commission
Quality assurance
Activities in building, checking, editing, documenting and finalising the database (Version 1) for Levels I-III included:
- reviewing and resolving loading errors from the data compiler to the database;
- providing data custodians with detail of errors and requesting resupply of outstanding map units;
- preparing plots of Levels I-III to visualise the data and attempt to resolve spatial errors;
- checking database entries against known code sets; and
- incorporating changes into the database in consultation with data custodians.
The majority of inconsistencies in classification and mapping across jurisdictions were unable to be resolved with data custodians in the time frame for the project. This required an intensive process of consultation with vegetation experts across each jurisdiction resulting in a resolution to change vegetation descriptions and mapped boundaries.
Version 1 of the database was used in the development of products for the Australian National Vegetation Assessment 2001.
Information gaps
Detailed vegetation mapping available for the 2001 assessment was incomplete for the entire continent and a number of gaps occur in our knowledge and on the coverage at regional scales (see Knowledge, data and information gaps section). An analysis of these gaps by users provides a rigorous basis for setting priorities for further investment in native vegetation mapping.
Reporting on Australia's native vegetation
Additional, readily available information was compiled to develop the major vegetation groups to enable Australia-wide assessments.
The assessments of the status and extent of Australia's native vegetation detailed in this report have been based on information from the National Vegetation Information System as well as sourcing other information to complete the assessment of Australia's present and pre-European vegetation.
The level of detail that can be used to describe the vegetation at broad scales constrained the description of Australia's vegetation to:
- 23 major vegetation groups; and
- a further 42 major vegetation subgroups being developed.
These products are designed for broad use at national and State-wide scale and are very useful for simple vegetation descriptions at regional scales. Appendix 10 outlines the development of these groups.
Within these limitations these assessments have provided the first hierarchical classification of Australia's native vegetation at an Australia-wide scale with the ability to access comparable finer-scale regional information where it exists.
Version control
The long-term success of the National Vegetation Information System is based on continuing collaboration and partnership with all States and Territories. The first steps are complete and Australia has an agreed set of attributes and systems for transferring, storing, validation, analysing and reporting vegetation information.
A review of these guidelines and systems and incorporation of identified changes will ensure that the National Vegetation Information System is a success in the long term. As new information is collected and existing data is compiled, validated and updated, the National Vegetation Information System will continue to change and improve. Through the development process, it has become evident that a national coordinator is vital to support activities of data custodians and continue the coordination and facilitation role of the Audit. This coordinator would:
- continually improve and manage the National Vegetation Information System framework;
- evaluate and develop improved systems for storage and reporting of data and their progressive implementation by all data custodians;
- oversee and validate data and information as new versions and information products are developed; and
- coordinate and disseminate technical advances in vegetation mapping.
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