Extent

Changes to Australia’s native vegetation have been extensive across various regions in the 200 or more years following European settlement.  Arguably the most dramatic impacts have been in the south eastern corner of the continent. As a result Government agencies and various NGOs (e.g. IUCN) have regularly used the residual extent of native vegetation and changes to this measure over time as a metric of ecological integrity / intactness / disruption. For this reason obtaining accurate various representations and measures of native vegetation are of keen interest to many people and sectors.

Determining the extent of native vegetation may initially appear to be a relatively simple task given the rich wealth of information including remote sensed data such as satellite imagery, etc.  However, determining and ‘mapping’ what is and is not native vegetation is actually quite complex problem, particularly when attempting to produce products that are useful at operational scales, rather than coarser-grained products at continental scales that often used for reporting purposes.

There are many issues to consider apart from granularity or resolution. The breadth of vegetative forms across south eastern Australia ranges from alpine grasslands, dense temperate rainforests, dry woodlands, mallee, heathlands, chenopod shrublands, to treeless grasslands / savannah. Some of these vegetation forms are naturally rare, and may be difficult to detect. Some others may have been cleared totally, and therefore are no longer extant, and our knowledge is limited to historical records.  However most vegetation forms will currently exist at some level of depletion compared to their pre-settlement extent.

Condition

There are also other issues that are very pertinent to determining the characteristics of native vegetation, such as the idea or concept of ‘condition’ or ‘quality’.  In many respects all locations may be considered as ‘native’ that could be placed on a continuum from ‘pristine’, through a gradient of degradation to a state that eventually would be considered as having no residual ‘condition’.

Capturing information on vegetation condition and developing products that are useful at operational scales is something that the EAS group has pioneered.  This includes the development of the ‘habitat hectares’ method of determining vegetation condition.  This method and its variants have become widely used by many agencies across Australia and internationally. The EAS group have been involved in recent considerations of improvements and refinements to vegetation condition metrics for conservation management.  Important amongst the refinements include the pressing need to improve capabilities for monitoring and evaluating the efficacies on conservation investments.

Modelling these features

Developing spatial models of vegetation features forms a large part of our work.  We are currently in the process of revising the mapping of extent, condition and ‘type’ across Victoria.  This has included sourcing a large amount of new data on the floristics and condition of vegetation across large areas of south eastern Australia, subsequent to a gap analysis of the existing data.

In a similar way to species distribution modelling we use a range of innovative computational & modelling approaches that enable the integration of field data with spatial information relevant to the distribution and other attributes of plants and their various associations.

Why it matters

As mentioned above, spatial layers or ‘maps’ of native vegetation extent and condition play major roles in monitoring ecological performance, but are also extremely useful as inputs to considering investments for conservation species and communities as well as in the regulatory space.  These data are regularly requested and used by both government and non-government agencies.