Dave Gillieson, Mia Thurgate and Stuart Bremner (Jenolan Caves Reserve Trust)

The Jenolan Caves Reserve is a series of steep valleys with limestone cliffs in the southern Blue Mountains. Two major natural arches, the Grand Arch and the Devil’s Coachhouse, block off the valleys of McKeowns and Camp Creeks. Each valley has significant vegetation communities including tall open forest, open woodland, native grasslands and vine thickets. Endangered species such as the Brush Tailed Rock Wallaby, Petrogale penicillata, are associated with ledge systems on the steep limestone cliffs that flank the valleys. The methodology is based on investigation of the landscape ecology of limestone terrains in terms of spatial structure, ecosystem function and the relative roles of patch size, connectivity and shape in the integrity of the plant communities. Also, an evaluation of the relative merits of Landsat TM satellite imagery, airborne multispectral video imagery, and colour aerial photography for vegetation mapping of complex limestone terrains is being carried out. This project is funded by an ARC grant as well as significant ongoing logistic support from the Jenolan Caves Reserve Trust.

An important part of the study is an evaluation of the relative merits of Landsat TM satellite imagery (25m cells), airborne multispectral video imagery (1m cells), and colour aerial photography (0.5m cells) for vegetation mapping of complex limestone terrains. These data will be integrated in the ArcView geographic information system (GIS). This allows us to query the data and produce customised maps for users eg. a map of north-facing limestone scrubs with roads and streams overlain, or a terrain map showing the distribution of the rare plant Geranium graniticola in the Reserve.

The expected outcomes of the project will be:

• Production of (GIS) data layers encompassing terrain, geology, soils, structural and floristic vegetation types, weed extent, habitat suitability and locations of rare and threatened plant species.
• Identification of key habitats containing rare and threatened plant species to enhance management planning.
• Identification and mapping of habitat suitability for endangered animal species such as the Brush-tailed Rock Wallaby Petrogale penicillata.

We are also working on a vegetation survey of the Jenolan Caves Reserve which will continue for several years. Lists of plant species and a vegetation map in terms of dominant tree species already exist for the Reserve, but the precise status, locations and environmental associations of many species are unknown. This is especially true for the four rare and threatened plant species known to occur at Jenolan. Already Guide Ian Eddison has found the rare Geranium graniticola at over forty locations, while the shrub Stemmacantha australis has also been located on the Reserve These records are now in the GIS database which contains details of over 180 surveyed quadrats in the Reserve.

The procedure for this project has involved the following steps:

• Collect and collate all available information of land attributes (geology, soils, vegetation) relevant to the investigation (virtually complete, thanks to the Resource Inventory)
• Acquire the best available field mapping topographic base (complete - we have digital mapping for the whole catchment plus fine detail over the Caves Precinct )
• Carry out a brief field survey to identify likely land units and land systems (completed)
• Carry out aerial photograph and satellite image interpretation to create a preliminary land classification (completed)
• Carry out field mapping and survey to refine land unit boundaries and acquire ecological data with which to build the GIS (completed)
• Construct GIS data layers and conduct analysis of the mapped vegetation types in terms of area, environmental correlation, connectivity and shape.

Ultimately this mapping will provide a sound basis for redefining above-ground management units at Jenolan and the development of specific strategies for each of them, rather than the more generalised scheme now in place. It will also enable management to implement the ecological risk management strategy devised by Bruce Gall of the Social & Environmental Monitoring Committee.

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