A complete list of PCTs is centrally managed by the Department of Planning and Environment in BioNet. It is known as the PCT master list and is rigorously controlled.
Scheduled maintenance and revisions are undertaken to ensure the PCT classification remains based on contemporary, best-available information.
Any changes to the PCT master list, or to the underlying geospatial information defining a PCT, are managed across all related data and map products in the Integrated BioNet Vegetation Data (IBVD) program.
For more information about PCTs visit the NSW PCT classification webpage.
Governance
Executive custodianship for the NSW vegetation classification hierarchy, including the PCT master list, resides with the Executive Director Science, Economics and Insights, Department of Planning and Environment.
PCT master list version control
Version protocols are in place to control changes to the PCT master list or to the underlying geospatial information defining a PCT. A version number is applied to each version of the PCT master list. The version number provides reference to a formal set of PCT definitions at a point in time. It also provides a reference between the PCT master list and the spatial representation of types in the State Vegetation Type Map (SVTM).
The version numbering system adopts an open-ended code structure using the format C1.1.
- The letter C denotes ‘classification’ to differentiate from map-based version codes that apply the prefix ‘M’ in the SVTM.
- A change to the first number indicates a change to the PCT master list, meaning one or more PCTs (PCT IDs) have been added or removed from the list of Approved PCTs in the master list.
- A change to the second number indicates amendments to the spatial definition of one of more PCTs, within a PCT master list version.
- The version number starts at C1.1 and this represents the PCT master list at 24 June 2022.
Log of PCT master list versions
Log of changes to the PCT master list, or to the underlying geospatial information defining PCT(s), from 24 June 2022 onward.
|
PCT classification version number |
Date of release |
Summary of changes |
|
C1.1
|
24 June 2022
|
|
Evidence for change
Improvements to the PCT master list and PCT definitions are expected as new information becomes available.
New vegetation surveys are continuously building on the body of available data, particularly as standard floristic survey methods are increasingly applied across NSW. The collection of standard floristic survey plot data is strongly encouraged as the most efficient and effective method for evaluating the PCT master list and assessing the need for changes.
In eastern NSW PCTs are almost all ‘quantitative’, meaning they have member plots defined in BioNet. Explicit rule sets can be applied to new data to determine relationships to existing quantitative PCTs. New standard floristic survey plot data may be formally classified to support or expand the definition of an existing type, or provide compelling evidence for description of a new PCT.
In western NSW PCTs are ‘qualitative’. New standard floristic survey plot data is used to assess PCTs, but less explicit methods are applied to determine relationships to existing types. In this region PCTs rely on the expert synthesis of classification source data, because standardised information, including survey plot data, has an uneven, patchy coverage. As a result new data are assessed using qualitative methods.
Tracking changes to the PCT master list
When a PCT(s) is replaced by a new type, it is no longer in use and is called ‘Decommissioned’. Decommissioned PCTs stay visible in the BioNet Vegetation Classification application. Relationships from old (Decommissioned) to new (Approved) PCTs are known as ‘lineage transformations’ and are held in the BioNet Vegetation Classification application.
Lineage data can be viewed individually for each PCT or exported in bulk in spreadsheet format.
Lineage data are comprised of:
- a ‘transformation details’ lineage statement that provides a short summary of the relationship between the Decommissioned PCT (or parent PCT) and the new Approved PCT(s) (or offspring PCT(s))
- a separate row for each Approved PCT to which the Decommissioned PCT is related
- the date the lineage information was entered into BioNet.
Lineage relationships are determined in different ways depending on the PCTs involved.
Wherever possible, classified floristic survey plots are used. The plot membership of Decommissioned PCTs is compared to that of revised PCTs, providing traceable and quantifiable lineage relationships. Because the quantitative PCT classification is based on and defined by floristic survey plots that are publicly available in BioNet, future PCT revisions will use transparent traceable data to determine lineage relationships.
Changes to other PCT attributes
Other PCT attributes are also subject to change. Such changes are carefully managed and controlled, but are not covered by the version number system described above. This includes changes to the PCT’s Vegetation Formation or Vegetation Class, threatened biodiversity association data or vegetation condition benchmarks.
Changes to other PCT attributes are generally considered during routine annual update cycles, but requests to review PCT attributes can be made at any time to BioNet.