Authors Geoffrey Hope, Rachel Nanson and Peter Jones Current addresses Emeritus Professor Geoffrey Hope Department of Archaeology and Natural History, College of Asia and the Pacific, Australian National University, Canberra, ACT 0200 Dr Rachel Nanson Australian School of Petroleum Science, University of Adelaide, North Terrace, SA 5005 Mr Peter Jones Commonwealth Department of Agriculture, Fisheries and Forestry, PO Box 858, Canberra City, ACT 2601 Disclaimer The views and opinions expressed in this report are those of the authors and do not necessarily represent the views, opinions or policy of the NSW Government. © Copyright State of NSW and the Office of Environment and Heritage The Office of Environment and Heritage and the State of NSW 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. Published by: Office of Environment and Heritage 59–61 Goulburn Street PO Box A290 Sydney South 1232 Phone: (02) 9995 5000 (switchboard) Phone: 131 555 (environment information and publications requests) Fax: (02) 9995 5999 TTY: (02) 9211 4723 Email: [email protected] Website: www.environment.nsw.gov.au ISBN 978-1-74293-558-4 OEH 2012/0257 April 2012 Series editor: Genevieve Wright Published with the support of the Australian National University and the Australian Alps national parks Co-operative Management Program Front cover: Alpine shrub bog and fen in the Cup and Saucer area, upper Geehi River. Photo: G Hope Peat-forming bogs and fens of the Snowy Mountains of NSW Technical Report SUMMARY Bogs and fens are common in the Snowy Mountains of south-eastern New South Wales (NSW) and form up to 2.5% of the higher altitude land cover in Kosciuszko National Park. At lower altitudes peat deposits beneath extensive sedge fens fill broad valleys on gentle slopes. With increasing altitude the hummock moss, Sphagnum cristatum, contributes to shrub-rich montane, subalpine and alpine bogs which follow drainage lines and seepage areas on slopes and saddles. These peatlands are vital areas of moist habitat and of high scientific significance biogeographically. Additionally, their slowly accumulating peat is an archive of past change in vegetation and fire regimes. This peat and associated organic-rich mineral soils are a significant carbon store. While similar fens and bogs occur in Victoria and the Australian Capital Territory (ACT), the occurrences in the Snowy Mountains represents the most extensive expression of peatlands in mainland south-eastern Australia with major environmental significance as habitat and as regulators of water quality. The peatlands have been badly affected by cattle grazing and fire since European settlement of the region commenced in 1823. Some recovery is evident within protected areas but serious fires in 2003 reversed this process in many areas. This study provides the first comprehensive mapping of the region’s peatlands. It has been completed by using aerial photography and satellite imagery, supplemented by field checking, to create a spatial database of the mires. The boundaries generally reflect the situation in February 2003, immediately after a major fire prompted the collection of high resolution aerial photographs of the peatlands. The surface extent of the peatlands is combined with data on the depth of peat and its carbon content to estimate peat volumes and carbon storage. The accumulation history of the mires provided by a 30-year program of coring and radiocarbon dating was used to estimate the long term rates of peat accumulation and carbon sequestration. This report provides the first quantified measurements of peatland extent, peat volume and peatland carbon storage for the Snowy Mountains. The 9120 individual peatlands in the Snowy Mountains region total 7985 ha, of which 6037 ha is in Kosciuszko National Park, 556 ha in the ACT, and 1392 ha in other reserves or on leasehold or freehold land. Some 72% is smaller than 0.5 ha. The 3656 ha of Sphagnum shrub bog in Kosciuszko National Park can be compared to the 2713 ha of bog in alpine Victoria and the 2865 ha of Sphagnum moss communities that occur above 800 m in Tasmania. The Snowy Mountains bogs and fens preserve 49 million cubic metres of peat, of which 27.1 million cubic metres is in bogs and moorlands and 21.9 million cubic metres is in sedge fen. The estimated total carbon store is 3.55 million tonnes. Measuring peat growth over the past 100 years shows that the historical carbon sequestration rate is only 4950 t C/year for the entire peat estate. This net carbon storage rate of 0.8 to 1.6 t C/ha/year is comparable to the rates found in temperate mires in other parts of the world. Peat sections covering the last 3000 to 4000 years indicate that the millennial-scale rate of long-term storage is 2340 t C/year (53% of the historical rate); part of this lower net rate may represent losses caused by grazing and fire. Most of the peatlands exhibit damage from the period of grazing last century, but those at higher altitudes are recovering strongly and recolonising erosion areas. The peatlands are vulnerable to hydrological changes caused by grazing and trampling by large mammals such as horses. They are also sensitive to climate change, as they are near their climatic limits and have been greatly stressed by past disturbance and fire. Recovery of the peatland vegetation will take several decades, but replacement of lost peats will be a much longer process. For this reason, active management of the hydrology, surface stabilisation, and reduction of disturbance are essential to restore peatlands and maintain their resilience to natural change. The report recommends further research in ecology and peatland processes to inform management. Programs of training for managers and education for the public are also needed. ACKNOWLEDGMENTS Mapping of the NSW bogs began in 2005, when it was funded by a research grant from the Parks and Wildlife Group, Office of Environment and Heritage (P&WG). The original remit was to map the outlines of peatlands in Kosciuszko National Park, but we have indulged our curiosity by extending the survey to the Snowy Mountains region as a whole and attempting a more detailed analysis of vegetation, peat types and history. This expansion has extended the length of the project by 2 years, and the tolerance of various responsible officers in P&WG has been severely tested, for which we apologise. Permission to undertake the field component was provided to the authors by Kosciuszko National Park. We are indebted to Dave Darlington, Rob Gibbs, Andrew Miller, Elouise Peach, Geoff Robertson and Matt White for authorisations, advice and substantial field support. We are particularly grateful to Genevieve Wright for managing the project on behalf of P&WG. The geographical information system (GIS) mapping was developed for both this and a parallel project on the peatlands of the ACT by Rachel Nanson, with additions by Iona Flett and Peter Jones and advice from Lyn Finch (Office of Environment and Heritage) and Tony Sparks (Ecowise). We are grateful for help with the field survey from Iona Flett, Roger Good, Simon Haberle, Ben Keaney, Justine Kemp, Colin de Pagter, Bren Weatherstone, Jennie Whinam and Genevieve Wright. Barry Cooper and Jim Kelton provided valuable information about Tomneys and MacPhersons plains in the Bago State Forest area. This report builds on several decades of mire studies by palaeoecologists and ecologists from the Australian National University, P&WG, the Commonwealth Scientific &and Industrial Research Organization (CSIRO), the NSW Soil Conservation Service and the Tasmanian Department of Primary Industry, Parks, Environment and Water. We have greatly benefited from discussions on the ecology and palaeoecology of the mires with John Banks, Mark Butz, Geoff Cary, Robin Clark, Fiona Coates, Alec Costin, John Dodson, January Finn, Roger Good, Ken Green, Kate Harle, Dave Hunter, Joe Jennings, Peter Kershaw, Michael Macphail, Merna McKenzie, Tony Martin, Scott Mooney, Stuart Pearson, Warwick Papst, Nick Porch, Arne Tolsma, Alan Wade, Janet Williams, Dane Wimbush, Gen Wright, Jennie Whinam and Phil Zylstra. We owe a debt to Keith McDougall (Biodiversity Conservation Section – South) for his comprehensive floristic surveys at Kosciuszko and the Victorian Alpine National Parks. Funding for mire stratigraphy, pollen analyses and carbon dating was provided by NSW National Parks and Wildlife Group, Office of Heritage and the Environment, the Australian National University, the Australian Nuclear Science and Technology Organisation, Ecowise Environmental and ACT Parks, Conservation and Lands. We thank the Australian National University for hosting the GIS and providing logistic and laboratory support. Thanks to Kay Dancey who calculated altitudinal zone areas from the GIS and drafted the figures. Adam Black and Ann Munroe solved numerous problems in preparing the manuscript for publication. CONTENTS SUMMARY ................................................................................................................................. 3 ACKNOWLEDGMENTS ............................................................................................................. 5 INTRODUCTION ........................................................................................................................ 1 PEATLANDS AND MIRES ........................................................................................................