Appendix H An Assessment of the Potential Implications on Native Vegetation and Terrestrial Ecosystems Not government policy Commercial in confidence Proposal for raising Eden Bann Weir and construction of Rookwood Weir An Assessment of the Potential Implications on Native Vegetation and Terrestrial Ecosystems Pre-feasibility study commissioned by Department of Natural Resources and Water for Department of Infrastructure Nangura E S i Not government policy Commercial in confidence Prepared by: ______________________________________________________________________________ Cameron James and Samantha Evans Nangura Environmental Services 303 Rockonia Rd North Rockhampton QLD 4701 August 2007 Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Queensland Department of Natural Resources and Water has taken all reasonable steps to ensure the information contained in this publication is accurate at the time of publication. Readers should ensure that they make appropriate enquires to determine whether new information is available on the particular subject matter. Cover photo: Melaleuca fringing woodland, Fitzroy R. near Glenroy Crossing courtesy of : C. James © The State of Queensland (Department of Natural Resources and Water) 2007 This report has been prepared by the consultant for the purpose of providing information to the proponent of the proposed project. It does not represent government policy. ii Not government policy Commercial in confidence Executive Summary This vegetation study examines the distribution and composition of fringing woodland and other native vegetation adjacent to parts of the Fitzroy, Dawson and MacKenzie Rivers in central Queensland. This work supports detailed environmental planning for the proposal to raise the Eden Bann Weir and construct a new Weir at the Rookwood site. Such detail was not currently available through Government vegetation datasets which are based on 1:100,000 scale mapping. The study involved an extensive vegetation survey, preparation of vegetation mapping at a scale of 1:25,000 and assessment of significant flora species potentially relevant to the weir study areas. Habitat condition was assessed for each vegetation community within the weir study areas using a bio- condition analysis methodology. The assessment generated local benchmark values for a key subset of alluvial habitats. The bio-condition assessment was subsequently applied to 24 disturbed not-remnant areas of vegetation within or near the upper river bank that may represent potential habitat recovery areas that could be used to offset losses through inundation after weir construction. The vegetation mapping produced a GIS layer of Regional Ecosystems (RE) for each weir impoundment and these are included as a series of 16 A3 mapping sheets at 1:25,000. The survey data recognised numerous variations to the standard 1:100,000 RE mapping data produced by the Queensland Herbarium, with most of the variations relating to edges of the mapping units and reassignment of mapping unit labels resulting from more extensive on-ground sampling intensity. A total of 240 plants were recorded with 10 being classed as rare or threatened under the Nature Conservation (Wildlife) Regulation 2006. Only one of these species, Eucalyptus raveretiana- (vulnerable) was found to have populations that would be directly impacted by the proposed weir developments. Up to 100 individual Eucalyptus raveretiana plants may be affected at maximum inundation levels. The 1:25,000 mapping for both weirs suggests that one hectare of an Endangered RE (brigalow) would be affected at proposed maximum levels, along with 225 hectares of Of Concern RE’s and a further 1677 hectares of riverine and alluvial Regional Ecosystems listed as Not of Concern. The alternative EPA bio-status classification suggests that 1908 hectares of Of Concern RE’s would be inundated at maximum development levels The mapping of remnant vegetation above predicted Full Supply Level (FSL) for the weirs indicates the potential extent of impacts on riverine and alluvial ecosystems at the landscape scale. Remnant vegetation losses (Endangered and Of Concern RE taking into consideration both VMA status and EPA biostatus) include: Eden Bann 18.5m AHD FSL=449.5ha; Eden Bann 20.5m AHD FSL=740ha; Rookwood 47m AHD FSL=847ha; Rookwood 49m AHD FSL=1168ha. Narrowing of corridors, further fragmentation of many small remnants along with breakdown of existing linkages, and localised loss of ecosystem diversity will all result from inundation to FSL. The bio-condition analysis found no sites for any habitat in near-pristine condition yet did conclude that roughly one third of sites were in relatively good condition for the 2006 landscape along the lower Fitzroy alluvial areas. Another third of the bio-condition sampling sites rated as having ‘average’ condition, and frequently included some weeds in the ground layers and other de-valuing impacts that possibly relate to recent grazing regimes and/or past logging activities. The proximity of extensive areas of cleared alluvial plain reduced the bio-condition score averages across most of the study area. The bio-condition assessment of the not-remnant regrowth areas found that habitat elements essential for long term recovery were lacking or highly degraded. The condition assessments suggest that many sites would be unlikely to recover rapidly without management support that may include fencing to control grazing pressure, revegetation, artificial nest boxes, weed management and other site specific measures. Preliminary investigations into potential vegetation management offsets identified (for the not-remnant regrowth on alluvial areas near the respective weir proposals) up to 474ha at Eden Bann 20.5m AHD FSL and up to 370ha at Rookwood 49m AHD FSL. The suitability and adequacy of these offsets will need to be determined and negotiated at the development approval stage, based on the offset policy and development assessment code applicable at the time. iii Not government policy Commercial in confidence TABLE OF CONTENTS 1.0 Introduction .......................................................................................................................................1 2.0 Methodology......................................................................................................................................1 3.0 Results and Discussion ......................................................................................................................3 3.1 Vegetation Distribution: Regional Ecosystems .............................................................................3 3.2 Regional Ecosystem Descriptions .................................................................................................6 3.3 Regional Ecosystems Potentially Affected by Inundation...........................................................19 3.4 Comparison with EPA’s RE Mapping......................................................................................... 23 3.5 Lower Fitzroy Weir Flora: Native and non-native flora ..............................................................24 3.6 Potential Commercial Timber - Salvage Logging .......................................................................25 3.7 Rare and Threatened Species.......................................................................................................26 3.8 Essential Habitat Mapping........................................................................................................... 34 4.0 Bio-condition Assessment and Benchmarking – Remnant Vegetation ...........................................35 4.1 Comments on Bio-condition Assessment ....................................................................................35 4.2 Bio-condition Analysis ................................................................................................................35 4.3 Bio-condition Result – Habitat Condition at Property Level....................................................... 36 4.4 Bio-condition Assessment Benchmarks ......................................................................................46 4.5 Bio-condition – Long-term Reference Sites ................................................................................47 5.0 Riparian Offset Zones and Bio-condition Review........................................................................... 48 5.1 Riparian Offset Zone Site Consideration.....................................................................................49 5.2 Description of Riparian Offset Zones..........................................................................................49 6.0 Recommendations ........................................................................................................................... 54 7.0 Acknowledgements .........................................................................................................................55 8.0 References .......................................................................................................................................55 Table 1 Regional Ecosystems of the Lower Fitzroy Weirs Study Area...................................................3 Table 2 Spatial Extent in hectares of RE’s affected by Inundation (excluding open water)..................19 Table 3 Significant Weeds found in the Vicinity of the Lower Fitzroy Weir Study