NSW Plant Community Type classification

Plant Community Types (PCTs) are widely used to support biodiversity assessment, conservation planning and land management activities.

PCTs are the finest level in the NSW vegetation classification hierarchy. They identify and describe recurring patterns of native plant species assemblages in relation to environmental conditions (soil, temperature, moisture and other factors). The floristic composition of PCTs is characterised by frequently co-occurring species, including combinations of trees, shrubs and/or ground cover plants.

PCTs play a central role in the NSW Biodiversity Offsets Scheme. Assessments of biodiversity values hinge on the identification of PCTs when using the Biodiversity Assessment Method (BAM).

PCTs are defined and mapped across NSW. PCT data are managed as part of the Integrated BioNet Vegetation Data (IBVD) program.

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The list of PCTs for NSW is centrally managed by the Department of Planning and Environment in BioNet.

In version C1.1 of the PCT master list there are 1841 Approved PCTs.

Each PCT has a unique name and identification number. A summary list of PCT names, numbers and other PCT data is available by clicking ‘download’ on the BioNet Plant Community Type Data page. The complete set of PCT description data is available in the BioNet Vegetation Classification application.

Changes to the master list of PCTs are carefully managed and generally occur in an annual update or when a major revision of PCTs is complete.

When a PCT is replaced by a new type(s), it is no longer in use and is called ‘Decommissioned’. Decommissioned PCTs remain visible in the BioNet Vegetation Classification application. Information is recorded in the application to track the relationships between the old (Decommissioned) and new (Approved) PCTs. These are known as ‘lineage transformations’.

Visit the PCT change control webpage for more information about lineage transformations.

Send questions or feedback about the PCT master list to BioNet.

PCT classification data and maps are accessible from a growing number of applications, which all draw from BioNet.

The BioNet Vegetation Classification application offers a range of PCT search, filter and export functions. Each PCT has standard attributes that describe species composition, habitat, distribution, relationships to higher levels in the vegetation classification hierarchy and other information. See more information about the BioNet Vegetation Classification application.

For eastern NSW PCT reference plot locations are available in the Flora surveys module of the BioNet Atlas application and via the SEED portal. A  short video demonstrates how to access floristic survey plots in SEED. See more information about the Flora surveys module of BioNet Atlas and access plots in an area of interest on the SEED portal.

PCT classification data can also be accessed via BioNet web services. A refreshable spreadsheet with a pre-configured connection to PCT description data from BioNet web services is available to download on the BioNet Plant Community Type Data page.

PCTs are mapped in the NSW State Vegetation Type Map (SVTM). The SVTM shows the pre-clearing extent and the current distribution of PCTs. The maps record the version number of the PCT master list used. Some PCTs are not represented in the SVTM for various reasons. See more information about the SVTM and access maps from the SEED portal and the Trees Near Me NSW app.

The Plot to PCT Assignment Tool is available to assess PCT choices using standard floristic survey plot data in eastern NSW. Visit the Plot to PCT Assignment Tool webpage for more information.

PCTs are defined using the best available information. Classification methods vary between eastern and western NSW, but together aim to provide a comprehensive set of types that describe fine scale patterns in native vegetation.

In eastern NSW, PCTs are defined from a large statistical analysis of floristic survey plots held in BioNet Atlas PCTs that have member plots defined in BioNet are known as ‘quantitative’ PCTs. They apply explicit data-driven methods and rules and have transparent and easily accessible relationships to reference plot locations. Detailed technical documents describing the classification methods for eastern NSW are available from Technical documents below.

In western NSW, PCTs predominantly adopt the framework and units of Benson (Benson 2006, Benson et al. 2006, Benson 2008, and Benson et al. 2010). This work overcame the scarcity of vegetation data in the region at the time by synthesising existing literature, maps and available data, as well as field checking, to assemble units of similar scale. These PCTs do not have member plots defined in BioNet, and are known as ‘qualitative’ PCTs.

When an adequate coverage of standard floristic survey plot data is captured for western NSW, the Department intends to extend quantitative PCT classification methods to the region.

Vegetation surveys provide the primary data on which the PCT classification is built. Increasingly, standard floristic survey methods are applied across NSW, enabling classification to be supported by large computer-based statistical analyses. 

A large collection of existing floristic survey plot data is available in the Flora surveys module of the BioNet Atlas application and is now used in the definition of quantitative PCTs in eastern NSW.

New standard floristic survey plot data, collected and added to BioNet Atlas, forms the basis for undertaking PCT revisions. Vegetation surveys are completed for a wide range of purposes, including implementation of the Biodiversity Assessment Method (BAM) or to target poorly surveyed regions and locations. Wherever standard floristic survey plot data are collected and entered into BioNet Atlas they can be combined to enable ongoing improvements to the PCT classification.

In eastern NSW, an online Plot to PCT Assignment Tool provides a standardised repeatable statistically-driven method for accurate plot-based identification of PCTs.

For western NSW, and for users without standard floristic survey plots, the PCT data, maps and applications described in the ‘How to access PCT data and maps’ section can be used in combination to shortlist PCTs. The BioNet Vegetation Classification application has a filter tool that enables users to shortlist PCTs based on geographic, floristic and other criteria.

Threatened Ecological Communities (TECs) are legal entities that are independently listed under provisions in the NSW Biodiversity Conservation Act (2016) or the Commonwealth Environment Protection and Biodiversity Conservation Act (1999). Independent scientific committees oversee the listing processes in each jurisdiction.

TECs are defined using an assemblage of species and an area, and not all are plant assemblages.

Associations between PCTs and TECs are recorded in the BioNet Vegetation Classification application. These associations are based on an interpretation of the components of each TEC, as only a small number of TECs cite a PCT directly. The principles used to identify PCT-TEC relationships in eastern NSW are available in Appendix E and F of Updating BioNet Plant Community Types: Eastern NSW PCT Classification Version 1.1 (2022).

PCTs are either not associated with a TEC, are partly associated with a TEC, or are entirely associated with a TEC. Qualifying statements are often required to indicate the components of a PCT, either distribution or floristic attributes, that meet the TEC definition. Qualifying statements are stored in the ‘TEC Comments’ field in the BioNet Vegetation Classification application and are important to consider when using the PCT-TEC association data.

Multiple PCTs may meet the definition of a single TEC where the TEC applies to widely distributed plant assemblages and habitats.

Classification of PCTs relies on standard floristic survey plot data, sampling the range of vegetation communities across the state.

The best way to contribute to the development and ongoing refinement of PCTs is to collect high quality standard full floristic survey plot data, such as when using the Biodiversity Assessment Method (BAM), and to enter it into the Flora surveys module of BioNet Atlas.

Watch the short video: How to contribute systematic flora survey records to BioNet Atlas.

Send any questions or feedback about the PCT classification, including suggestions for corrections to the master list of PCTs, to BioNet.