Extant Native Vegetation of Boorowa Shire and surrounds VIS_ID 1624

"Extant Native Vegetation of Boorowa Shire and surrounds.;
Vegetation map based on classified vegetation survey data, and modelling layers, derived from a 25 metre Digital Elevation Model, and a composite geology map derived from Department of Minerals geology data. Data derived from the following sources: Digital elevation model in integer format, 25 m grid cells, produced 1997, Land Information Centre; Catchment variables derived from DEM, using Arcview 3.2; Geology data from 1:250 K Geology Map, Department of Mineral Resources of NSW; Derived Elevation, Slope Steepness, Drainage from DEM; Combined Geology and sub-catchments within Boorowa Shire; Derivation of individual grid layers for each map unit; Compilation of individual map units, using merge request function in Arcview 3.2; Derivation of vegetation mask, using Landsat ETM band 5 to create a native forest/woodland cover map; Intersection of pre-european vegetation map with M305 native woody vegetation map to produce extant layer.;
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Method used was based on expert modelling of vegetation types, based on consultant EcoGIS's (Nic Gellie) knowledge of distribution of similar vegetation types in relation to lithology and broad landscape variables. To reduce possible error in expert models, modelling zones based on a combination of lithology classes and sub-catchments were produced from expert examination of the spread and patterns of each vegetation group. The modelling zones helped to reduce the number of vegetation groups to be modelled down to 2-3 groups;
Careful inspection of sites within each vegetation group helped to determine the broad environmental niche of each vegetation group.  A table of possible relationships between vegetation groups and environmental variables was drawn up to help with the modelling process. It was clear that the patterns of vegetation in the study area were more influenced by geochemistry of the lithology classes and topographic position in the landscape, rather than the conventional aspect and moisture relationships found in coastal higher rainfall environments. This conclusion helped to determine the development of terrain variables that could separate vegetation groups that occurred predominantly on ridges and hillslopes from those vegetation groups that occurred in valley bottoms. A neighbourhood variable, using stream pattern derived from the watershed models within Arcview, helped to distinguish hillslopes from valley bottoms.;
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The modelling process enabled a complete audit of all vegetation types mapped in the study area and allowed a transparent and flexible process of mapping to be documented. In the event that detailed inspection of the results of the model or field validation resulted in possible changes to the map, individual modelling zones could be remodelled with the new knowledge, or new site data. This approach also prevented grid layers from spreading to areas where the vegetation groups would logically not occur in. When all modelling zones had been modelled, the resultant grid layers were then compiled into a single Arcview view. The data layers were then sorted into an agreed order of precedence that enabled each grid layer to be displayed on the final vegetation map. Reclassification and merge request functions within Arcview Spatial Analyst then produced a pre-European vegetation map. The final pre-European vegetation map was then masked with an extant vegetation cover to produce an extant vegetation map.";
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VIS_ID 1624;
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ANZLIC: ANZNS0208000217

Tags: Vegetation
Organization: NSW Department of Climate Change, Energy, the Environment and Water