Climatic and Oceanographic Effects on Survival of Little Penguins in Southeastern Australia
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SCIENTIA MANU E T MENTE CLIMATIC AND OCEANOGRAPHIC EFFECTS ON SURVIVAL OF LITTLE PENGUINS IN SOUTHEASTERN AUSTRALIA A thesis submitted for the degree of Doctor of Philosophy By Lucia-Marie Ganendran Applied and Industrial Mathematics Research Group, School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Australian Defence Force Academy. December 2017 PLEASE TYPE THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: Ganendran First name: Lucia-Marie Other name/s: Billie Abbreviation for degree as given in the University calendar: PhD School: School of Physical, Environmental and Mathematical Faculty: UNSW Canberra Sciences Title: Climatic and Oceanographic Effects on Survival of Little Penguins in Southeastern Australia Abstract 350 words maximum: (PLEASE TYPE) Climate change can impact on the survival of seabirds. While many studies have investigated the influences of climatic and oceanographic variables on seabird breeding, fewer have been able to capture the processes affecting survival. In this study, I carried out a mark-recapture analysis on a 46-year penguin dataset to study the effects of some climatic and oceanographic variables on the survival of little penguins Eudyptula minor in southeastern Australia. A priori knowledge of the birds' annual cycle and patterns of movement informed my selection of meaningful and biologically sensible variables. Two age classes of penguins were considered, based on their differing patterns of movement: first-year birds and adult birds in their second and subsequent years of life. The climatic and oceanographic variables considered in this study were wind strength, sea-surface temperature, east-west sea temperature gradient, air temperature, rainfall, humidity and chlorophyll a concentration. Climatic covariates which affected adult penguins on land had a direct impact on their survival, most likely via physiological stresses caused by climatic extremes. Oceanographic covariates had contrasting effects on first-year and adult penguin survival. Positive effects were most likely due to the movement of nutrients and associated prey into foraging areas as a result of favourable marine conditions, while negative effects were most likely due to a decrease in prey abundance, or physical factors such as changes in sea-surface temperature or turbulent seas, which affected prey availability or foraging behaviour. The survival probabilities of first-year and adult birds were most strongly associated with different covariates, and at different times during the birds' annual cycle. The effects were not always immediate, with lagged covariates found to affect survival for both age classes. In a broader context, the effects of any single covariate on the distribution and demography of penguins may be correlated with, or masked by, a range of environmental conditions and interactions between covariates in the marine ecosystem. My research offers new insights into processes which affect penguin survival, and ultimately population security. The development of appropriate management and adaptation actions will further contribute to the conservation of seabirds. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all property rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstracts International (this is applicable to doctoral theses only). …………………………………………………………… ……………………………………..……………… ……….……………………...…….… Signature Witness Signature Date The University recognises that there may be exceptional circumstances requiring restrictions on copying or conditions on use. Requests for restriction for a period of up to 2 years must be made in writing. Requests for a longer period of restriction may be considered in exceptional circumstances and require the approval of the Dean of Graduate Research. FOR OFFICE USE ONLY Date of completion of requirements for Award: Certificate of Originality I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial pro- portions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educa- tional institution, except where due acknowledgment is made in the thesis. Any contribution made to the research by oth- ers, with whom I have worked at UNSW or elsewhere, is ex- plicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project's design and conception or in style, presentation and linguistic expression is acknowledged. Signed .................................................... Date ...................................................... i Copyright Statement I hereby grant the University of New South Wales or its agents the right to archive and to make available my thesis or disser- tation in whole or part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstract International (this is applicable to doctoral theses only). I have either used no substantial portions of copyright material in my thesis or I have obtained permission to use copyright material; where permission has not been granted I have applied/will apply for a partial restriction of the digital copy of my thesis or dissertation. Signed .................................................... Date ...................................................... ii Authenticity Statement I certify that the Library deposit digital copy is a direct equiv- alent of the final officially approved version of my thesis. No emendation of content has occurred and if there are any minor variations in formatting, they are the result of the conversion to digital format. Signed .................................................... Date ...................................................... iii Abstract Climate change can impact on the survival of seabirds. While many studies have investigated the influences of climatic and oceanographic variables on seabird breed- ing, fewer have been able to capture the processes affecting survival. In this study, I carried out a mark-recapture analysis on a 46-year penguin dataset to study the effects of some climatic and oceanographic variables on the survival of little pen- guins Eudyptula minor in southeastern Australia. A priori knowledge of the birds' annual cycle and patterns of movement informed my selection of meaningful and biologically sensible variables. Two age classes of penguins were considered, based on their differing patterns of movement: first-year birds and adult birds in their second and subsequent years of life. The climatic and oceanographic variables considered in this study were wind strength, sea-surface temperature, east-west sea temperature gradient, air temperature, rain- fall, humidity and chlorophyll a concentration. Climatic covariates which affected adult penguins on land had a direct impact on their survival, most likely via phys- iological stresses caused by climatic extremes. Oceanographic covariates had con- trasting effects on first-year and adult penguin survival. Positive effects were most likely due to the movement of nutrients and associated prey into foraging areas as a result of favourable marine conditions, while negative effects were most likely due to a decrease in prey abundance, or physical factors such as changes in sea- surface temperature or turbulent seas, which affected prey availability or foraging behaviour. The survival probabilities of first-year and adult birds were most strongly associated with different covariates, and at different times during the birds' annual cycle. The effects were not always immediate, with lagged covariates found to affect survival for both age classes. In a broader context, the effects of any single covariate on the distribution and demography of penguins may be correlated with, or masked by, a range of environmental conditions and interactions between covariates in the v marine ecosystem. My research offers new insights into processes which affect pen- guin survival, and ultimately population security. The development of appropriate management and adaptation actions will further contribute to the conservation of seabirds. vi Acknowledgements I will always be grateful to my supervisor, Leesa Sidhu, for her mentorship through- out my program. She has been a wonderful role model with her boundless patience, kindness and encouragement. My PhD experience will always be defined by her support and guidance. Thank you, Leesa, for making these past few years ones that I will always treasure. Harvi Sidhu and Peter Dann, my two co-supervisors, have been wonderfully