Western Port Welcomes Waterbirds: Waterbird Usage of Western Port
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Western Port Welcomes Waterbirds: Waterbird Usage of Western Port Maximum of Three Lines B. Hansen, P. Menkhorst and R. Loyn 2011 Arthur Rylah Institute for Environmental Research Technical Report Series No. 222 Arthur Rylah Institute for Environmental Research Technical Series No. 222 Western Port Welcomes Waterbirds: waterbird usage of Western Port Birgita Hansen, Peter Menkhorst and Richard Loyn Arthur Rylah Institute for Environmental Research 123 Brown Street, Heidelberg, Victoria 3084 June 2011 In partnership with: Arthur Rylah Institute for Environmental Research Department of Sustainability and Environment Heidelberg, Victoria Report produced by: Arthur Rylah Institute for Environmental Research Department of Sustainability and Environment PO Box 137 Heidelberg, Victoria 3084 Phone (03) 9450 8600 Website: www.dse.vic.gov.au/ari © State of Victoria, Department of Sustainability and Environment 2011 This publication is copyright. Apart from fair dealing for the purposes of private study, research, criticism or review as permitted under the Copyright Act 1968, no part may be reproduced, copied, transmitted in any form or by any means (electronic, mechanical or graphic) without the prior written permission of the State of Victoria, Department of Sustainability and Environment. All requests and enquiries should be directed to the Customer Service Centre, 136 186 or email [email protected] Citation: Hansen, B., Menkhorst, P. and Loyn, R. (2011) Western Port Welcomes Waterbirds: waterbird usage of Western Port. Arthur Rylah Institute for Environmental Research Technical Report Series No. 222. Department of Sustainability and Environment, Heidelberg, Victoria ISSN 1835-3827 (print) ISSN 1835-3835 (online) ISBN 978-1-74287-182-0 (print) ISBN 978-1-74287-183-7 (online) Disclaimer: This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. Front cover photo: An example of an unmodified coastal environment at Spit Point, French Island: a high-tide waterbird roosting site on the exposed sand spit with mangroves, saltmarsh, Melaleuca scrub and eucalypt woodland behind. (Photographer Peter Menkhorst). Authorised by: Victorian Government, Melbourne Printed by: NMIT Printroom, 77–91 St Georges Road, Preston 3072 ii Contents List of tables and figures...................................................................................................................v List of Acronyms ............................................................................................................................. vi Acknowledgements......................................................................................................................... vii Summary............................................................................................................................................1 1 Introduction.............................................................................................................................3 1.1 Background to project...............................................................................................................3 1.2 Waterbirds in Western Port.......................................................................................................5 1.2.1 Information on waterbird breeding in Western Port..................................................8 1.2.2 Broad-scale influences on waterbird numbers...........................................................9 1.2.3 Local influences on waterbird numbers.....................................................................9 1.3 Current land uses and threats to waterbird populations ............................................................9 1.3.1 Disturbance..............................................................................................................11 1.3.2 Climate change risk assessment ..............................................................................12 1.4 Project objectives....................................................................................................................13 2 Methods..................................................................................................................................14 2.1 Site description .......................................................................................................................14 2.2 Data acquisition ......................................................................................................................14 2.2.1 Waterbird monitoring data ......................................................................................15 2.2.2 Spatial data ..............................................................................................................15 2.2.3 Other data ................................................................................................................15 2.3 Field survey.............................................................................................................................15 2.4 Data analysis...........................................................................................................................16 2.4.1 Preliminary trend analyses ......................................................................................16 2.4.2 Modelling of trends .................................................................................................16 2.4.3 Analyses of site importance.....................................................................................17 2.5 Movements of banded birds....................................................................................................18 2.6 Mapping..................................................................................................................................18 2.6.1 Existing mapping information.................................................................................18 2.6.2 Construction of waterbird maps ..............................................................................19 2.7 Assessment of climate change inundation risk .......................................................................19 2.8 Community engagement .........................................................................................................19 3 Results....................................................................................................................................20 3.1 Opportunistic field surveys.....................................................................................................20 3.1.1 Observations of breeding.........................................................................................22 iii 3.2 .................................................... Population trends and responses to explanatory variables 22 3.2.1 Modelling ................................................................................................................23 3.2.2 General species by site trends..................................................................................26 3.3 Sites of importance .................................................................................................................26 3.4 Movements of banded birds....................................................................................................32 3.5 Mapping..................................................................................................................................34 3.6 Climate change risk ................................................................................................................38 3.7 Threats at key sites..................................................................................................................40 4 Discussion ..............................................................................................................................43 4.1 What influences waterbird population dynamics in Western Port?........................................43 4.1.1 Changes in local fisheries........................................................................................43 4.1.2 Reduced rainfall and water availability...................................................................45 4.2 What are the causes of waterbird declines? ............................................................................46 4.3 Important areas for waterbirds in Western Port......................................................................47 4.3.1 Habitat use by shorebird species .............................................................................47 4.3.2 Habitat use by other waterbird species....................................................................50 4.3.3 Breeding sites ..........................................................................................................51 4.4 What threats are operating at key sites?..................................................................................52 4.5 Climate change risks...............................................................................................................53 4.6 Management recommendations ..............................................................................................55