Simulating natural cavities in Slender Cypress Pine (Callitris gracilis murrayensis) for use by Major Mitchell’s Cockatoo (Lophochroa leadbeateri leadbeateri): A report to the Department of Environment and Primary Industries Report Title: “Simulating natural cavities in Slender Cypress Pine (Callitris gracilis murrayensis) for use by Major Mitchell’s Cockatoo (Lophochroa leadbeateri leadbeateri): A report to the Department of Environment and Primary Industries.” Prepared by: Dr Victor G. Hurley Senior Strategic Fire and Biodiversity Officer Department of Environment and Primary Industries 308-390 Koorlong Ave Irymple VIC 3498 Email: [email protected] Telephone: 5051 4610 And Grant J. Harris Ironbark Environmental Arboriculture Charles Street Fitzroy Melbourne VIC 3065 ABN: 14 667 974 300 Email: [email protected] Telephone: 0415 607 375 Report Status: Final 21 December 2014 The State of Victoria Department of Environment and Primary Industries Melbourne 2014 This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. This document may be cited as: Hurley, V.G. and Harris, G.J., (2014) “Simulating natural cavities in Slender Cypress Pine (Callitris gracilis murrayensis) for use by Major Mitchell’s Cockatoo (Lophochroa leadbeateri leadbeateri): A report to the Department of Environment and Primary Industries.” Cover photographs: Hauling new cavity cover plate with the elevated work platform (Grant Harris ©). ACKNOWLEDGMENTS This project was funded by the Victorian Environmental Partnerships Program (VEPP) in 2013-15. Thanks go to David Christian and Matthew Baker for arranging logistical support and access to Parks Victoria facilities. Much appreciation to Ewan Murray who worked in the field in collecting and recording data and capably wielding the chainsaw and chipper and for field and occasional ambulance assistance. Special thanks to FM Watson for recreating a usable Style Guide and K Learmonth and N Schedvin for proof reading and providing valuable comment on a late draft of the document. © The State of Victoria Department of Environment and Primary Industries 2014 This work is licensed under a Creative Commons Attribution 3.0 Australia licence. You are free to re-use the work under that licence, on the condition that you credit the State of Victoria as author. The licence does not apply to any images, photographs or branding, including the Victorian Coat of Arms, the Victorian Government logo and the Department of Environment and Primary Industries logo. To view a copy of this licence, visit http://creativecommons.org/licenses/by/3.0/au/deed.en ISBN: 978-1-74146-443-6 pdf Accessibility If you would like to receive this publication in an alternative format, please telephone the DEPI Customer Service Centre on 136186, email [email protected], or via the National Relay Service on 133 677 www.relayservice.com.au. This document is also available on the internet at www.depi.vic.gov.au 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. Contents Contents 2 List of figures 3 List of tables 3 Executive Summary 4 Introduction 4 Project Objectives/Outcomes 4 Conclusion 4 Recommendations 5 Introduction 6 Background 6 Project Objectives 7 Methods 8 Tree selection 9 Cavity dimensions 11 Results 12 Statistics 12 Discussion 14 Recommendations 15 References 18 Appendix I 16 Box plots of tree and cavity measurements 16 Comparing simulated natural cavities to natural cavities in Callitris 2 List of figures Figure 1. The future of Victoria’s largest Major Mitchell’s Cockatoo breeding population depends upon the successful development of techniques to form cavities in Callitris to simulate natural cavities. .................... 5 Figure 2. Counts of nest sites used by Major Mitchell’s Cockatoo (Lophochroa leadbeateri leadbeateri) at Pine Plains, Wyperfeld National Park from 1995 to 2014. = Annual count of nest trees remaining. = 2 count of remaining nest trees (March 2014). Black trend line = linear regression, R = 0.894..................... 7 Figure 3. Conceptual time line of tree growth and appropriate growth stages for SNC intervention. Letters represent the location of SNC techniques in the temporal sequence of large old tree development and loss. I = Initiate, E = Excavation, A = Augmentation and R = Restoration. ................................................... 9 Figure 4. Decision matrix for the selection of the appropriate technique in simulated cavity formation in Slender Callitris Pine (Callitris gracilis murrayensis). Diamonds are decision points and light orange boxes are actions. The orange strips represent recording and monitoring activities. The pale orange rectangles represent actions or SNC techniques. ........................................................................................................ 10 Figure 5. Measurements of naturally occurring Major Mitchell’s Cockatoo nest cavities in Callitris tree trunks (n = 55) (figure adapted from Hurley (2006)). A = horizontal entrance diameter or width, B = vertical entrance diameter, C = cavity depth to nest chamber floor, D = maximum diameter of nest chamber floor, E = minimum diameter of nest chamber floor and F = nest chamber wall thickness. ........................ 11 Figure 6. Counts of nest sites known to be used by Major Mitchell’s Cockatoo (Lophochroa leadbeateri leadbeateri) at Pine Plains, Wyperfeld National Park from 1995 to 2008. = Annual count of nest trees remaining. = count of remaining nest trees (March 2014). = Count of nest trees including simulated natural cavities (May 2014). Black trend line = linear regression, R2 = 0.894. Orange line = 2 linear regression following the inclusion of simulated natural cavities, R = 0.822. .................................... 13 Figure 7. Diameter at breast height (DBH) of Callitris trees with natural (n = 55) and simulated cavities (n = 25). st rd Mean is the dark line, grey boxes are the 1 and 3 quartiles and the whiskers are the range. ................. 16 Figure 8. Height of cavity entrance above ground in Callitris trees with natural (n = 55) and simulated cavities (n st rd = 25). Mean is the dark line, grey boxes are the 1 and 3 quartiles and the whiskers are the range. ..... 16 Figure 9. Width (horizontal diameter) of cavity entrance in Callitris trees with natural (n = 55) and simulated cavities (n = 25). Mean is the dark line, grey boxes are the 1st and 3rd quartiles and the whiskers are the range. ................................................................................................................................................... 16 Figure 10. Height (vertical diameter) of cavity entrance in Callitris trees with natural (n = 55) and simulated cavities st rd (n = 25). Mean is the dark line, grey boxes are the 1 and 3 quartiles and the whiskers are the range. 16 Figure 11. Cavity depth from entrance to nest chamber floor in Callitris trees with natural (n = 55) and simulated cavities (n = 25). Mean is the dark line, grey boxes are the 1st and 3rd quartiles and the whiskers are the range. ................................................................................................................................................... 17 Figure 12. Average diameter of nest chamber floor in Callitris trees with natural (n = 55) and simulated cavities (n st rd = 25). Mean is the dark line, grey boxes are the 1 and 3 quartiles and the whiskers are the range. ..... 17 Figure 13. Average thickness of nest chamber walls in Callitris trees with natural (n = 55) and simulated cavities (n st rd = 25). Mean is the dark line, grey boxes are the 1 and 3 quartiles and the whiskers are the range. ..... 17 List of tables Table 1. Dimensions of naturally occurring Callitris cavities used by Major Mitchell’s Cockatoo breeding in Pine Plains (n = 55). The ‘Key’ values relate to the labels in Figure 4. Listed are the median, mean and the standard deviation (SD) of the mean. Adapted from Hurley (2006). .......................................................... 11 Table 2. Cavity features measured in Slender Cypress Pine tree cavities and statistics (range, median, mean ± standard deviation, sample size and the percentage of live trees) for each method of nest cavity creation from those excavated, augmented, restored or nest-box averaged for all simulated cavities combined (n = 27). ...................................................................................................................................... 12 Table 3. Comparison of Simulated Natural Cavity production processes. Listed are the advantages and restrictions in the application of each process and the estimated longevity of each process. ..................... 14 Comparing simulated natural cavities to natural cavities in Callitris 3 Executive Summary Introduction The availability of tree cavities is a limiting resource for a range of Victorian fauna (Gibbons & Lindenmayer, 2002; Manning et al., 2013; Saunders et al., 2014). As a result, loss of hollow bearing trees has been listed as a threatening process under the Flora and Fauna Guarantee Act 1988 (FFG Act). This project addresses the shortage of tree cavities