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Plant community types: Frequently asked questions

How do the plant community types relate to BioMetric vegetation types?

The BioMetric vegetation types (BVTs) are the communities that are used in the BioMetric tools which underpin Property Vegetation Plans and BioBanking assessments. The BVTs have been integrated into the plant community type (PCT) classification, and are now managed in the VIS Classification (version 2.0) database (as shown in the diagram below). 

Diagram showing Plant Community Types occurrences in specific catchment authority areas

While the PCT classification represents the full geographic distribution of each plant community, the BVT classification focuses on its occurrence within specific catchment management authority (CMA) areas. A PCT may be distributed across one or more CMA administration areas and is assigned a BVT with each CMA occurrence. This allows a small set of CMA-specific attributes to be managed (e.g. percentage of the vegetation type remaining in the CMA). All other community attributes are recorded at the PCT level.

When the BVTs need to be updated in the BioMetric-based regulatory tools (such as the BioBanking Credit Calculator), a combination of PCT and CMA-specific attributes are exported from the VIS Classification (version 2.0) database in the format required by the BioMetric tools.

The PCT classification was derived initially by associating and aligning BVTs sourced from the native vegetation regulation database PADACS (Property Vegetation Plans, including agreements, data and customer service). This was done to minimise the impact on the existing regulatory tools and processes by eliminating unnecessary changes to the pre-existing BVTs. Some minor changes occurred as a consequence of standardising common attributes between BVTs, such as plant community names.

All changes and updates to the BVT are now managed through the VIS Classification (version 2.0) database.

How do the plant community types relate to the NSW Vegetation Classification and Assessment database and type classification?

Vegetation classification and assessment (VCA) refers to both the vegetation community classification and the database developed by the Royal Botanic Gardens and Domain Trust (Benson 2006 & 2008). In 2009, the original NSW VCA MS Access database was migrated into a new online application called VCA Web 1.1.and the NSW VCA MS Access database was retired. Both applications only contained the VCA classification. The NSW VCA and VCA1.1 databases have now been superseded by the VIS Classification database (version 2.0) which contains the new plant community type (PCT) classification.

The initial PCT classification was created by adopting the statewide BioMetric vegetation types (BVT) classification and matching each BVT with VCA types (where the latter occurred) in the western 70% of NSW. This matching was possible because the VCA classification had been adopted and referenced in the BVT classification, which is the basis of the initial PCT classification. That is, the PCT was developed in the following steps:

  • the BVT classification (sourced from  PADACS) was adopted across NSW
  • identical BVT types in adjacent CMAs were amalgamated to create new PCTs, while existing BVT identification numbers and other CMA-specific attributes were retained against the new PCT
  • VCA types in western NSW were matched to the BVTs and the more extensive VCA attributes were adopted.

Where VCAs and BVTs could not be matched, both classifications were retained, introducing the potential for duplicate or synonym types to co-exist. This potential occurs predominantly in the hatched overlap zone as shown in the map below. The PCT classification that occurs in the overlap zone will need to be reviewed, ideally as an extension to any systematic revision of the PCTs that are scheduled to the east. This may provide an additional benefit of cross-regional harmonisation of the PCT. A more immediate triage of the classification may resolve most uncertainties by matching and clumping similar types.

 

Map of NSW showing Vegetation Classification Assessment (VCA) in the west, BioMetric Vegetation Types (BVT) in the east and VCA and BVT overlap zones

 

The VIS Classification database (version 2.0) represents the next generation of the NSW VCA database. The attribution used to describe communities has largely been adopted from the previous VCA model with some exceptions. Modifications include the adoption of the fields required by the BioMetric tool, and adoption of the National Vegetation Information System (NVIS) Level 5/6 Attributes. (ESCAVI, 2003). The NVIS attributes are a nationally agreed standard to describe vegetation communities that are used to ensure that the classification is both compatible with other systems and extensible (i.e. supporting derivation of alternative classifications and products).

What is the relationship between the plant community type classification and threatened ecological communities?

Threatened ecological communities (TECs), which include endangered ecological communities, are defined and listed under both the NSW Threatened Species Conservation Act 1995  and Commonwealth Environment Protection and Biodiversity Conservation Act 1999. In both cases the plant community types (PCTs) and TECs are different classifications that have been developed independently of each other.

The relationship between PCTs and TECs is described in terms of their equivalence to each other. This is managed in several ways:

  • Each PCT community includes a description of its relationship and degree-of-fit to both NSW and Commonwealth listed TECs. Once PCTs are mapped, the potential extent and location of each TEC can be inferred through this relationship.
  • PCTs are described using an extensible classification system (based on NVIS Level 5/6 Attributes) that will support more accurate mapping of TECs in the future.
  • As new TECs are listed under NSW legislation, it is expected that they will better align to, and reference, the PCT communities to which they correspond.
  • Equivalence to TECs may also be managed as attributes of vegetation type maps.

Should I be mapping to the plant community type classification?

The plant community type (PCT) classification is designed to be the NSW standard for community-level vegetation mapping. However, the PCT classification is relatively immature and will need to undergo further refinement before all communities are defined to a minimum standard needed for vegetation mapping. Many plant communities, particularly on the east coast, are still poorly defined. The classification is being upgraded in this area.

Prior to deciding whether to map to the PCT classification, you should first assess the quality of the classification available in your study area. The 'Classification confidence level' and 'Completeness of attribution' indicate the quality of the PCT classification.

As a general rule, at least 80% of the PCTs in your target mapping area should meet the minimum requirements of both these factors as described below.

Classification confidence level

Classification confidence level (CCL) reflects the quality of the evidence underpinning the identification and classification of a particular PCT. Each PCT is rated at a CCL of between 1 and 5 (see Table 1). Communities rated at CCL 4 or 5 may not be suitable for mapping and will require further work before mapping commences. Generally, PCTs with a low or very low classification confidence level should not be used in vegetation mapping.

Table 1: PCT Classification confidence level mapping

Classification confidence level

PCT mapping

Level 1 - Very high confidence

Desirable

Level 2 – High confidence

Desirable

Level 3 – Moderate confidence

Desirable

Level 4 – Low confidence

Not desirable

Level 5 – Very low confidence

Not desirable

Completeness of attribution

The PCT classification has been developed from a variety of classification sources, so the completeness of PCT attribution varies across the state. As a general rule, PCT classifications derived solely from BioMetric Vegetation Types (BVT) will not meet the minimum attribution level required for vegetation mapping. They do not carry the full suite of attributes required to describe a PCT and should not be used in vegetation mapping until this part of the PCT classification is upgraded (see Table 2).

PCTs derived from the NSW Vegetation Classification and Assessment (VCA) do not carry National Vegetation Information System (NVIS) level 5/6 attributes in the first instance, but these attributes may be derivable from other VCA attributes. These derived surrogates are of a lesser quality than those derived through a systematic plot-based classification but ensure that minimum requirements for mapping are met. Plot-derived classifications are likely to provide the best quality data particularly with regard to the NVIS level 5/6 floristic, structural and growth form attributes.

Table 2: Plant community type attributes mapping

 

Plant community type attributes

Is the PCT mappable?

Plant community type source

BioMetric vegetation type fields

NSW VCA fields

NVIS level 5/6 fields

 

NSW VCA

 

 

 

Derived surrogates

Desirable

Plot derived classification
(e.g. Greater Hunter; North Coast)

 

 

Observed

Desirable

BioMetric vegetation types

 

No data

No data

Not desirable

  Data available

Based on these factors, the PCTs east of the great divide are generally not suitable for mapping at this stage as most PCTs fall below the desirable 80% mappable threshold for both factors. However, there are a series of major re-classification projects under way or plans to upgrade the classification quality in this area.

If your study area meets the 80% mappable threshold, and you wish to proceed with mapping to the PCT classification, careful planning of your project may contribute to the upgrade of the classification in your area. This may include, for example, improving the evidentiary base for low rating PCTs through targeted flora surveys. Please contact the VIS team for further advice at VIS@environment.nsw.gov.au.

I already have a useful vegetation map for my study area, is it possible to upgrade it to the plant community type classification?

Yes, it is possible to upgrade your existing vegetation map by establishing an equivalence between your existing map units and each PCT. While it is the responsibility of the map custodian to undertake this task, the VIS team is currently developing tools that will assist. In particular, a standard data model is being developed to standardise data fields required to document PCT equivalences. This will be applied as a set of standard, and initially blank, fields against all vegetation maps held in the VIS map catalogue.

The map custodian will also be responsible for maintaining PCT equivalence in their mapping product, although this process will eventually be facilitated by the tracking of individual PCT lineage of changes in the VIS Classification database. This will flag what PCT has changed and what it has changed to. PCT lineage of change tracking will not be implemented in the east coast PCTs until major planned upgrades to the classification are finalised.

How will changes to the plant community type classification be managed?

The PCT classification will be revised and improved as better data becomes available. Improvements to the PCT will be evidenced-based and moderated by the NSW Plant Community Type Change Control Panel (PCTCCP) chaired by the Royal Botanic Gardens and Domain Trust. Significant changes to the PCTs will need to be endorsed by the PCTCCP.

Once PCTs are endorsed by the PCTCCP their status in the VIS Classification database (version 2.0) will be updated. Uploading the PCT derived BVTs into the BioMetric tools will occur periodically following synchronisation with the BioMetric vegetation condition benchmarks and threatened species profiles. Updates to these BioMetric databases occurs in accordance with Section 2.4.2 of the Environmental Outcomes Assessment Methodology (EOAM) (110157eoam.pdf, 1.83MB) established under the Native Vegetation Regulation 2005.

Lineage of PCT change will eventually be tracked in the VIS Classification database for all PCTs as a mechanism for maintaining synchronised vegetation maps.

Further advice on how you can contribute to the continuous improvement of the PCT classification, will be available shortly through the PCT Operational Standard, which is currently under development.

What are the underlying principles of the plant community type concept?

The guiding principles underpinning the management of the PCT classification are listed below.

  • The plant community type classification system is scientifically robust, including:
    • classify plant community types on the basis of inherent attributes and characteristics of the vegetation structure, growth form and plant species
    • use national standards for community data attribution (NVIS Attribute Manual, ESCAVI 2003) to facilitate the alignment and flow of information between systems
    • use the best available information, including where feasible, the use of quantitative plot data analysis to derive the type classification
    • ensure all elements of the methodology and inputs (including data, reports and maps) are publicly accessible to facilitate review and refinement
    • facilitate improvement to the type classification as better information becomes available
    • facilitate the progressive harmonisation of communities across NSW to eventually eliminate artificial boundaries created by administration zones and regional study areas
    • maintain the type classification through a review process, which may or may not involve publication in peer reviewed journals
    • ensure any changes to the type classification are clearly documented and traceable, to facilitate maintenance of dependent systems and programs.
  • The type classification is practical for use by conservation and resource management practitioners. The classification should be:
    • easily identifiable on the ground by field practitioners
    • suitable for use in vegetation mapping
    • suitable for use in NSW regulatory assessment tools
    • ecologically meaningful for property scale planning and management.
  • Progressive alignment with vegetation mapping is facilitated, recognising that that it may not be practicable to always establish a one-to-one relationship between the community type and the map unit.
  • Community types are organised according to the classification hierarchy outlined in the NSW Native Vegetation Interim Type Standard, with each of the more detailed plant community types nesting within a more generalised Vegetation Class and Formation in Keith D. 2004, From ocean shores to desert dunes.
  • Linkages to other classifications is facilitated, particularly those from adjoining states.
  • Alignment of the type classification with ecological communities listed under the NSW Threatened Species Conservation Act, 1995 and the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 is facilitated;
  • The classification is applicable over the full extent of NSW and Australian Capital Territory.
Page last updated: 21 January 2014