Wollemi National Park Broad Scale Vegetation Mapping VIS_ID 1849

"Wollemi National Park Vegetation.

Vegetation map digitised from: Bell, S.A.J. (1998). Wollemi National Park Vegetation Survey. A Fire Management Document. Report to the NSW National Parks and Wildlife Service, Upper Hunter District. Final Report, August 1998. Volumes 1 and 2.

Extensive vegetation survey and mapping of Wollemi National Park was carried out over much of 1997, adding substantially to the limited systematic survey previously completed in the area. Due to the large size of the Park (nearly half a million hectares), a stratified sampling procedure was employed to enable sampling of most variation present. This procedure considered geology, aspect, elevation, physiographical position, climate, broad vegetation type, and geographical location. In this way, a total of approx. 360 detailed floristic sites (current and previous surveys) were examined for floristic and structural variation, revealing a total of over 1360 plant species.

Seventy-two (72) vegetation communities have been delineated for Wollemi National Park, based on the current survey and that completed by previous workers. The diversity of vegetation types present in the Park includes representatives of rainforest, forest, woodland, scrub, heath, shrubland, sedgeland, swamp, grassland, reedland, and Sphagnum bog structural types. Cluster analysis of 358 detailed survey plots (200 completed during the current survey combined with 158 previously completed sites) was carried using the PATN computer package to assist delineation of communities, analysing cover abundance data with the Bray-Curtis association measure. Distinct identification of vegetation types was not always possible based on this analysis, due to the incorporation of datasets from a range of workers, as well as a lack of site replication from specific environmental strata and under-sampling of remote locations.

Following the techniques initially trialed in the mapping of Yengo National Park (Bell et al 1993), floristic vegetation communities occurring in Wollemi National Park have been mapped using the predictive modeling capabilities of the NPWS Arcview geographical system. While such techniques do lessen accuracy levels to some degree, the large size of the Park and the limited time available for extensive and detailed ground truthing and hand-based mapping warrant their use. Computer derived vegetation maps are considered the most economical alternative for mapping such large areas of land. During this process, the overlapping of specific environmental variables for each vegetation type (eg: geology, elevation, rainfall, broad vegetation, aspect) are utilised to determine the geographical distribution of that type on the ground.To assist in the modeling process, ten vegetation provinces were delineated for the area, based on distinct vegetation patterns observed from Landsat imagery, together with major geological and geomorphological features. These provinces essentially provide an additional layer (environmental variable) for use in computer manipulation and vegetation distribution prediction."

VIS_ID 1849