Assessment of Coastal Saltmarsh TEC on NSW Crown Forest Estate
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Assessment of Coastal Saltmarsh TEC on NSW Crown Forest Estate Survey, Classification and Mapping Completed for the NSW Environment Protection Authority www.epa.nsw.gov.au Environment Protection Authority © 2016 State of NSW and Environment Protection Authority With the exception of photographs, the State of NSW and Environment Protection Authority are pleased to allow this material to be reproduced in whole or in part for educational and non-commercial use, provided the meaning is unchanged and its source, publisher and authorship are acknowledged. Specific permission is required for the reproduction of photographs. The Environment Protection Authority (EPA) has compiled this report in good faith, exercising all due care and attention. No representation is made about the accuracy, completeness or suitability of the information in this publication for any particular purpose. The EPA shall not be liable for any damage which may occur to any person or organisation taking action or not on the basis of this publication. Readers should seek appropriate advice when applying the information to their specific needs. [where appropriate, e.g. guidelines that are sometimes or regularly updated: This document may be subject to revision without notice and readers should ensure they are using the latest version.] All content in this publication is owned by the EPA and is protected by Crown Copyright, unless credited otherwise. It is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0), subject to the exemptions contained in the licence. The legal code for the licence is available at Creative Commons. The EPA asserts the right to be attributed as author of the original material in the following manner: © State of New South Wales and the Environment Protection Authority 2016. Published by: Environment Protection Authority 59 Goulburn Street, Sydney NSW 2000 PO Box A290, Sydney South NSW 1232 Phone: +61 2 9995 5000 (switchboard) Phone: 131 555 (NSW only – environment information and publications requests) Fax: +61 2 9995 5999 TTY users: phone 133 677, then ask for 131 555 Speak and listen users: phone 1300 555 727, then ask for 131 555 Email: [email protected] Website: www.epa.nsw.gov.au Report pollution and environmental incidents Environment Line: 131 555 (NSW only) or [email protected] See also www.epa.nsw.gov.au ISBN 978-1-76039-533-9 EPA 2016/0626 October 2016 Contents Contents ................................................................................................................................. ii 1 Overview ........................................................................................................................ 1 2 Introduction .................................................................................................................... 2 2.1 Project Rationale ..................................................................................................... 2 2.2 Final Determination ................................................................................................. 2 2.3 Initial TEC Reference Panel Interpretation .............................................................. 2 2.4 Assessment Area .................................................................................................... 3 2.5 Project Team ......................................................................................................... 10 3 Methodology ................................................................................................................. 11 3.1 Approach ............................................................................................................... 11 3.2 Identifying Intertidal Landforms ............................................................................. 11 3.3 Existing Vegetation Data ....................................................................................... 14 3.4 Operational TEC Map ............................................................................................ 14 3.5 Validation .............................................................................................................. 14 4 Results ......................................................................................................................... 15 4.1 Operational TEC Mapping ..................................................................................... 15 4.2 Validation .............................................................................................................. 16 4.3 Final State Forest-TEC Occurrence Matrix ............................................................ 21 References .......................................................................................................................... 23 Assessment of Coastal Saltmarsh TEC on NSW Crown Forest Estate 1 Overview Coastal Saltmarsh is a threatened ecological community (TEC) associated with the intertidal zone on the shores of estuaries and lagoons along the NSW coast. Our study assesses whether Coastal Saltmarsh is located within the 1.4 million hectares of state forest found within the South, Central and North Coast regions of NSW. We used an agreed interpretation of the TEC by a project TEC Reference Panel (the Panel), to identify treeless saline and sub saline native vegetation found in the intertidal zone. A fine scale digital elevation model was used to estimate the highest astronomical tide line (HAT) to provide an indicative extent of the intertidal zone in our northern and southern study areas. Mapping of candidate saltmarsh TEC was undertaken using recent fine scale three- dimensional aerial imagery. Interpreters experienced in mapping native vegetation patterns identified categories of native vegetation that comprised low growing treeless communities within the HAT situated on the landward side of mangroves. Mapping criteria used a tolerance of tree cover of up to 30 percent to include areas that comprise a mixed cover of mangrove, paperbark and casuarina species (or combinations of all three) with a saltmarsh understorey. Exposed mudflats and banks were also mapped where visible. Our mapping identified 111.9 hectares of Coastal Saltmarsh restricted to 14 state forests along the East Coast. The most extensive areas are located in Bermagui and Mogo State Forests on the South Coast, and Wallaroo State Forest on the North Coast. We validated our map of Coastal Saltmarsh using an independent map of estuarine habitats produced by Creese et al. (2009). We mapped almost twice as much saltmarsh as Creese et al. (2009), and this was consistent across most state forests, although in Mogo State Forest we mapped significantly more. This is to be expected because the mapping criteria differed between studies, and areas we classified as saltmarsh have in some instances been mapped by Creese et al. (2009) as mangrove or not mapped at all. Conversely, we identified 12.6 hectares of saltmarsh mapped by Creese et al. (2009) in Wallaroo State Forest which we classified as mangrove. We revisited this area and concluded it is likely to be an attribution error in that study. 1 Assessment of Coastal Saltmarsh TEC on NSW Crown Forest Estate 2 Introduction 2.1 Project Rationale This project was initiated by the NSW Environment Protection Authority (EPA) and Forestry Corporation of NSW (FCNSW) as a coordinated approach to resolve long-standing issues surrounding the identification, extent and location of priority NSW Threatened Ecological Communities (TECs) that occur on the NSW State Forest estate included within eastern Regional Forest Agreements. 2.2 Final Determination Coastal Saltmarsh in the North Coast, Sydney Basin and South East Corner bioregions (Coastal Saltmarsh) was first gazetted as an Endangered Ecological Community on 4 June 2004 (NSW Scientific Committee 2004). Minor amendments to the determination were made in 2011. Paragraphs 1 and 5 of the final determination define the location and habitat of Coastal Saltmarsh as the intertidal zone on the shores of estuaries and lagoons where it is frequently found in a zone landward of mangrove stands. The species list presented in Paragraph 2 describes a treeless community of salt tolerant sedges, rushes and herbs. Paragraph 5 also describes some additional compositional attributes including occasional scattered mature Avicennia marina trees and Avicennia (and less frequently Aegiceras corniculatum) seedlings may occur throughout saltmarsh. Paragraph 5 also makes reference to a number of tall reed species that are included within Coastal Saltmarsh (Phragmites australis, Bulboschoenus spp., Schoenoplectus spp. and Typha spp.) however, these species are not included in the species listed in Paragraph 1. Adam et al. (1988) is referenced as a source of more extensive species lists than those used in Paragraph 1. Paragraph 7 of the final determination (NSW Scientific Committee 2011) refers to variation in compositional attributes of saltmarsh assemblages along the NSW coast. 2.3 Initial TEC Reference Panel Interpretation Under the Threatened Species Conservation Act 1995 (TSC Act), TECs are defined by two characteristics: an assemblage of species and a particular location. The TEC Panel agreed that the occurrence of Coastal Saltmarsh is constrained to the IBRA bioregions stated in the final determination. The Panel considered the characteristic species list but reached agreement that insufficient information was included to diagnose candidate areas at a site scale across the