Vegetation Mapping and Threatened Ecological Communities

When using vegetation maps it is important to realise the limitations of these maps. Errors and uncertainties are inherent in all maps because they are only representations of what is likely to be found on the ground. Not only are vegetation boundaries dynamic, vegetation communities will also have a zone of transition from one community to the next, known as an eco-cline.

Most vegetation maps are produced at a scale too coarse for property-scale identification of Threatened Ecological Communities, and typically miss many small vegetation patches as well as containing incorrectly labelled units (e.g. from unverified Air Photo Identification (API) mapping or modelled data). This means that it is difficult to use these maps at a property scale without adequate ground truthing and also means they are unreliable for accurately locating all remnants of Threatened Ecological Communities.

Vegetation mapping is also a very expensive undertaking, requiring a high level of expertise and resources, especially at the fine scales required to map Threatened Ecological Communities. For this reason vegetation maps are often modelled using data such as climate, aspect, elevation and soil from vegetation surveys and extrapolated across the landscape. Modelled vegetation maps can present a best guess scenario for where certain vegetation types will be found but cannot reliably identify all remnants of Threatened Ecological Communities. All vegetation assessments should therefore involve ground truthing.

Vegetation maps are great tool for locating vegetation types in the field but for the reasons outlined above should be used with a level of caution and all vegetation assessments should involve ground truthing when dealing with such vulnerable communities

Map Units

Vegetation Types are referred to in mapping projects as Map Units. The Final Determination of the NSW Scientific Committee for a Threatened Ecological Community identifies a number of map units (vegetation types) from various authors that may be considered to be part of that particular community, but it is important to remember that this is not a definitive list and other mapping units not identified on this list may also correspond to that Threatened Ecological Community. The description of the ecological community on the Final Determination is always the definitive source of information for identifying Threatened Ecological Communities – mapped vegetation units should only be used as a guide.

Some electronic vegetation mapping products are available from DECC at: http://maps.environment.nsw.gov.au/