Duralie Open Pit Modification Environmental Assessment
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Duralie Open Pit Modification Environmental Assessment APPENDIX E FLORA ASSESSMENT DURALIE OPEN PIT MODIFICATION FLORA ASSESSMENT PREPARED BY FLORASEARCH July 2014 Document No. 00601251.docx Duralie Open Pit Modification – Flora Assessment TABLE OF CONTENTS Section Page EXECUTIVE SUMMARY ES-1 1 INTRODUCTION 1 1.1 ASSESSMENT OBJECTIVES 1 1.2 REGIONAL SETTING 4 1.3 BIOGEOGRAPHICAL AND BOTANICAL REGIONS 4 1.4 DESCRIPTION OF THE STUDY AREA AND SURROUNDS 4 1.4.1 Topography 4 1.4.2 Soils 4 1.4.3 Land Use 5 1.4.4 Surface Hydrology 5 1.4.5 Climate 5 1.5 LITERATURE REVIEW 6 1.5.1 Regional Flora Surveys 6 1.5.2 Flora and Vegetation Surveys Conducted for the Duralie Mine 6 1.6 DATABASE REVIEW 9 1.6.1 Threatened Flora Species 9 1.6.2 Threatened Populations 14 1.6.3 Threatened Ecological Communities 14 1.6.4 Critical Habitat 14 2 METHODS 15 2.1 VEGETATION SAMPLING 15 2.1.1 Quadrat Sampling 15 2.1.2 Random Meanders 15 2.2 VEGETATION MAPPING 17 2.3 SPECIES LISTING 17 2.4 VEGETATION CONDITION ASSESSMENT 17 3 RESULTS AND DISCUSSION 19 3.1 VEGETATION COMMUNITIES 19 3.1.1 Hunter-Macleay Dry Sclerophyll Forests 21 3.1.2 Coastal Valley Grassy Woodlands 22 3.1.3 Dry Rainforests 23 3.1.4 Coastal Valley Grassy Woodlands 23 3.2 FLORA SPECIES 24 3.3 INTRODUCED FLORA SPECIES 24 3.4 CONDITION OF THE VEGETATION 25 3.5 THREATENED FLORA SPECIES 26 3.6 THREATENED ECOLOGICAL COMMUNITIES 26 3.7 NOXIOUS WEEDS 27 4 EVALUATION OF POTENTIAL IMPACTS ON FLORA 28 4.1 NATIVE VEGETATION/HABITAT CLEARANCE 28 4.1.1 Regional Context 28 4.2 POTENTIAL IMPACTS FROM IRRIGATION 29 4.3 LOSS OF HABITAT CONNECTIVITY 29 4.4 GROUNDWATER DEPENDENT ECOSYSTEMS 29 4.5 INTRODUCED FLORA 29 4.6 DUST AND VEGETATION 30 FloraSearch i Duralie Open Pit Modification – Flora Assessment TABLE OF CONTENTS (continued) 4.7 BUSHFIRE RISK 30 4.8 THREATENED FLORA 30 4.8.1 Threatened Flora Species listed under the TSC Act 30 4.8.2 Key Thresholds 31 4.8.3 Threatened Populations Listed under the TSC Act 32 4.8.4 Threatened Ecological Communities Listed under the TSC Act 32 4.8.5 Threatened Flora and Communities Listed under the EPBC Act 33 4.9 CUMULATIVE IMPACTS 33 4.9.1 Loss of Native Vegetation 33 4.9.2 Offset Strategy 33 4.9.3 Threatened Flora 33 5 IMPACT AVOIDANCE AND MITIGATION MEASURES 34 6 OFFSET MEASURES 35 6.1 EXISTING BIODIVERSITY OFFSET STRATEGY 35 6.2 PROPOSED BIODIVERSITY OFFSET STRATEGY 35 6.2.1 Offset Proposal - Management, Security, Monitoring and Auditing 36 6.3 FLORA CHARACTERISTICS OF THE PROPOSED OFFSET AREA 38 6.3.1 Regional Location 38 6.3.2 Existing Reserve System 38 6.3.3 Regional Conservation Priorities 38 6.3.4 Tenure of the Proposed Offset Area 39 6.3.5 Vegetation 39 6.3.6 Shape 39 6.3.7 Ecosystem Resilience and Condition 39 6.4 RECONCILIATION OF THE PROPOSED OFFSET STRATEGY AGAINST OEH OFFSET PRINCIPLES 40 6.5 ECOLOGICAL GAINS OF THE PROPOSED OFFSET 41 7 CONCLUSIONS OF THE ASSESSMENT 42 8 REFERENCES 43 LIST OF TABLES Table 1 Vegetation Types Previously Identified on the Study area and Surrounds and Equivalent Biometric Plant Community Types Table 2 Threatened Flora Species that may Potentially Occur within the Study Area Table 3 Threatened Flora Species Targeted for Impact Assessment Table 4 Modified Braun-Blanquet Cover Abundance Rating Scale Table 5 Sampling Effort Stratified by Vegetation Types Table 6 Plant Community Types Recognised on the Study Area Table 7 Community 1. Spotted Gum – Grey Ironbark – Thick-leaved Mahogany Open Forest Table 8 Community 2. Grey Box – Forest Red Gum – Grey Ironbark Open Forest Table 9 Community 3. Grey Myrtle - Flintwood dry rainforest Table 10 Map Unit A. Derived Grassland Table 11 Number of Native and Introduced Flora Species and the Total Number of Species Recorded in each Vegetation Community FloraSearch ii Duralie Open Pit Modification – Flora Assessment TABLE OF CONTENTS (continued) LIST OF TABLES (continued) Table 12 Vegetation Condition Table 13 Clearance of each Plant Community Type within the Modification Area Table 14 Estimated Percentage of Pre-European Extent of Plant Community Types Remaining in NSW Table 15 Threatened Flora Species Considered in this Assessment Table 16 Offset Strategy Completion Criteria Table 17 Existing and Proposed Offset Strategies Table 18 Quantification of Vegetation Types in the Disturbance Area and Offset Area Table 19 Reconciliation of the Proposed Offset Strategy against OEH Offset Principles LIST OF FIGURES Figure 1 Regional Location Figure 2 Modification General Arrangement Figure 3 Flora Survey Sites Figure 4 Plant Community Types LIST OF ATTACHMENTS Attachment A Flora Species List FloraSearch iii Duralie Open Pit Modification – Flora Assessment EXECUTIVE SUMMARY A flora survey of the Duralie Coal Modification area and proposed offset area was conducted by FloraSearch over three days in April and May 2014. Flora Communities and Species One natural climax vegetation community was recorded in the Modification area (i.e. Spotted Gum – Grey Ironbark Forest) as well as one derived vegetation type (i.e. Derived Grassland). Two natural climax vegetation communities were recorded in the offset area (i.e. Spotted Gum – Grey Ironbark Forest and Grey Box – Forest Red Gum – Grey Ironbark Forest) as well as two derived vegetation types (Derived Grassland and Acacia Regeneration. A total of 231 plant species was identified on quadrat plots and random meanders by the survey. Of these, 191 (82.7%) are native to the natural communities of the Study area and 40 (17.3%) are introduced. The plant families with the highest numbers of native species (Attachment A) were the Grasses, family Poaceae (26 species); the Pea Flowers, Fabaceae subfamily Faboideae (15 species); the Daisies, Asteraceae (11 species); the Eucalypts and related genera in the family Myrtaceae (13 species); the Rushes and Sedges, Cyperaceae (12 species) and the Wattles, subfamily Mimosoideae (7 species). In all, some 67 families of native plants were represented. Condition of the Vegetation The condition of the vegetation is assessed in detail for two parts of the Modification area and the offset area. In general, the remnant native vegetation is in good to very good condition in the Modification area, with the derived grasslands considered to be in poor condition. Similarly, most of the remnant native vegetation in the offset area is considered to be in very good condition with small areas in moderate condition. Derived grassland and acacia regeneration in the offset area are in poor condition. Threatened Species No flora species listed in the schedules of the TSC Act or EPBC Act were found in the targeted searches conducted over the Study area. Threatened Ecological Communities No ecological communities listed as threatened in the schedules of the TSC Act or EPBC Act, were found in the Modification or offset areas. Impacts A total of 2.5 hectares (ha) of native vegetation and derived grasslands would be removed by the Modification. Impact Avoidance, Mitigation and Offset The changes to the limit of the open pit are required to improve geotechnical stability, and therefore, additional disturbance associated with these changes to the open pit limit cannot be avoided without potentially impacting the long-term stability of the open pit low walls. FloraSearch ES-1 Duralie Open Pit Modification – Flora Assessment The relocation of existing water diversion infrastructure adjacent to the Clareval pit has been designed to occur within derived grassland wherever possible to avoid additional disturbance of native vegetation. In addition, the relocated water diversion infrastructure has been designed to avoid disturbance of Plant Community Type 3 (Grey Myrtle – Flintwood Dry Rainforest). Mitigation measures applicable to flora developed for the DCM are: • vegetation clearance procedures; • weed control and prevention; and • bushfire prevention. Biodiversity values would be maintained and improved in the region in the long-term with a proposed offset area. The proposed offset has a number of features that ensure it meets the ‘maintain and improve’ test. These include: • The offset removes an area of native vegetation from the deleterious effects of livestock grazing, thereby allowing it to recover and improve over time. • Cleared agricultural lands within the offset would be revegetated with local trees and shrubs appropriate to the positions in the landscape being replanted. • The offset area replicates, as far as practicable, the vegetation communities on the Modification area, thereby maintaining biodiversity in the region. • The new offset area adjoins an existing reserved offset area thereby enhancing the viability of each and nature conservation over the region as a whole. Conclusions It is concluded that the Modification would not have a significant impact on flora species, populations, ecological communities or critical habitat for the following reasons: • The 2.5 ha of native vegetation and derived grasslands that would be removed for the Modification is offset with 12.5 ha of similar native vegetation and derived grasslands close by. • The offset supports good samples of the dominant native vegetation communities within the Modification disturbance areas and has a greater diversity of vegetation communities than occur within the Modification area. • It is concluded that the offset area meets the NSW Office of Environment and Heritage offset principles and would result in a net improvement in regional biodiversity values. • The area of native vegetation to be cleared represents a very small proportion of the extant native vegetation in the local area and wider region. • Mitigation strategies are considered adequate to control risks to native flora arising from weed invasion, dust and fires. • The Assessment demonstrated the Modification is highly unlikely to impact significantly on any threatened flora species, or their habitats that may potentially occur on the Modification area.