The Native Vegetation of the Nattai and Bargo Reserves
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The Native Vegetation of the Nattai and Bargo Reserves Project funded under the Central Directorate Parks and Wildlife Division Biodiversity Data Priorities Program Conservation Assessment and Data Unit Conservation Programs and Planning Branch, Metropolitan Environmental Protection and Regulation Division Department of Environment and Conservation ACKNOWLEDGMENTS CADU (Central) Manager Special thanks to: Julie Ravallion Nattai NP Area staff for providing general assistance as well as their knowledge of the CADU (Central) Bioregional Data Group area, especially: Raf Pedroza and Adrian Coordinator Johnstone. Daniel Connolly Citation CADU (Central) Flora Project Officer DEC (2004) The Native Vegetation of the Nattai Nathan Kearnes and Bargo Reserves. Unpublished Report. Department of Environment and Conservation, CADU (Central) GIS, Data Management and Hurstville. Database Coordinator This report was funded by the Central Peter Ewin Directorate Parks and Wildlife Division, Biodiversity Survey Priorities Program. Logistics and Survey Planning All photographs are held by DEC. To obtain a Nathan Kearnes copy please contact the Bioregional Data Group Coordinator, DEC Hurstville Field Surveyors David Thomas Cover Photos Teresa James Nathan Kearnes Feature Photo (Daniel Connolly) Daniel Connolly White-striped Freetail-bat (Michael Todd), Rock Peter Ewin Plate-Heath Mallee (DEC) Black Crevice-skink (David O’Connor) Aerial Photo Interpretation Tall Moist Blue Gum Forest (DEC) Ian Roberts (Nattai and Bargo, this report; Rainforest (DEC) Woronora, 2003; Western Sydney, 1999) Short-beaked Echidna (D. O’Connor) Bob Wilson (Warragamba, 2003) Grey Gum (Daniel Connolly) Pintech (Pty Ltd) Red-crowned Toadlet (Dave Hunter) Data Analysis ISBN 07313 6851 7 Nathan Kearnes Daniel Connolly Report Writing and Map Production Nathan Kearnes Daniel Connolly EXECUTIVE SUMMARY This report describes the distribution and composition of the native vegetation within and immediately surrounding Nattai National Park, Nattai State Conservation Area and Bargo State Conservation Area. The purpose of the project has been to provide detailed information on the type, extent and condition of the native vegetation communities. The project addresses a long-standing need for detailed vegetation information to meet the needs of park management associated with water catchment protection as well as management of wilderness and world heritage conservation values. The information and associated data layers generated from this project can now be directly integrated into fire management planning and conservation related assessments. This mapping project extends the mapping work completed in the north of Nattai National Park under the mapping program for the Special Areas Plans of Management (SASPoM). Funding was provided by Central Directorate Parks and Wildlife Division to complete the southern half of Nattai National Park along with Bargo State Conservation Area and Bargo River Crown Reserves. The completion of this project provides a fine-scale vegetation mapping coverage from the Illawarra coast to Kanangra-Boyd National Park. A comprehensive field survey program was carried out to augment the information gathered in the Warragamba and Woronora Special Area mapping projects. An additional 69 floristic survey sites were collected, bringing the total number in the study area to 364 sites. All vascular plants were identified and vegetation, soil and disturbance information were recorded and entered into an electronic database. This data was used to classify vegetation communities using quantitative analytical techniques. Thirty-seven vegetation communities have been identified and described in a separate profile. Each profile describes the composition and structure of the vegetation, example locations, disturbance levels present and includes a sample photograph. The Nattai and Bargo reserves support a high level of floristic diversity. The diversity arises from the variations in soil and geological substrates, topographic variables, rainfall and elevation gradients. Within the reserves there are ten broad geology classes (Bryan, 1966; Rose, 1966); elevation that ranges from around 100 to 900 metres above sea level; rainfall ranging from approximately 700 to over 1000 millimetres per annum. Topographically the reserves include both narrow and broad sandstone tablelands, deeply incised valleys and escarpments and large river valleys supporting tall alluvial forests. Over 800 native flora species have been identified from field sampling and searches of existing literature. Structurally the vegetation varies between rainforest, tall forest, open forest, woodland, heath, mallee and swamps. The 37 vegetation communities include some typical of Sydney sandstone environments such as the shrubby forests across the Nattai Plateau, while the Burragorang Valley features dry grassy woodlands that have more in common with vegetation in the central west of NSW. Tall grassy forests found on shale and basalts of the Southern Highlands are uncommon within the reserves as were grassy and shrubby sandstone-shale transition forests. Three Endangered Ecological Communities (TSC Act, 1995) were located and a further 14 were classified as vegetation communities of regional significance. Twenty-two of the species recorded are either Threatened (TSC Act, 1995) or listed as a RoTAP (Briggs and Leigh, 1995). Of the Threatened Species four are listed as Endangered and a further five as Vulnerable. A 1: 25 000 scale map of the vegetation communities of the study area has been completed. This map was constructed using detailed Aerial Photograph Interpretation (API) of 1:25000 photography (1994) in conjunction with environmental data layers that describe the patterns in geology, elevation, rainfall and aspect. Digital data layers for use in ARCView GIS are available, which describe the distribution of vegetation communities as well as other landscape features such as exposed rock and cleared land. The derived mapping can now be used to display vegetation communities, vegetation structure, disturbance, amount of rock present, understorey type, canopy density and tree species present. This data can now be widely applied to a number of uses ranging from environmental reporting, fire management planning, conservation assessments and field operations. The Native Vegetation of the Nattai and Bargo Reserves 3 CONTENTS ACKNOWLEDGMENTS...............................................................................................................................2 EXECUTIVE SUMMARY..............................................................................................................................3 CONTENTS ..................................................................................................................................................4 1 INTRODUCTION...................................................................................................................................7 1.1 BACKGROUND ..................................................................................................................................7 1.2 APPROACH.......................................................................................................................................7 1.3 STUDY AREA ....................................................................................................................................7 1.3.1 Location...................................................................................................................................7 1.3.2 Environmental Setting.............................................................................................................8 1.3.3 Regional Context ..................................................................................................................16 2 METHODS...........................................................................................................................................19 2.1 REVIEW OF EXISTING INFORMATION.................................................................................................19 2.2 EXISTING SITE DATA.......................................................................................................................19 2.3 SURVEY STRATIFICATION AND SITE SELECTION................................................................................20 2.4 FIELD SAMPLING.............................................................................................................................20 2.5 SITE NOMENCLATURE .....................................................................................................................21 2.6 DATABASE STORAGE ......................................................................................................................22 2.7 TAXONOMIC REVIEW.......................................................................................................................22 2.8 AERIAL PHOTOGRAPH INTERPRETATION...........................................................................................22 2.8.1 Objectives .............................................................................................................................22 2.8.2 Area Mapped and Photography Used ..................................................................................22 2.8.3 Aerial Photo Interpretation and Landcover Classification.....................................................23 2.8.4 Patterns in Vegetation Cover................................................................................................23