Identifying the Effects of Anthropogenic Disturbance on the Breeding Behaviour of Female Grey Seals (Halichoerus Grypus), at a Mainland UK Colony
Total Page:16
File Type:pdf, Size:1020Kb
Durham E-Theses Identifying the eects of anthropogenic disturbance on the breeding behaviour of female grey seals (Halichoerus grypus), at a mainland UK colony. HOLT, AMY,REBECCA How to cite: HOLT, AMY,REBECCA (2015) Identifying the eects of anthropogenic disturbance on the breeding behaviour of female grey seals (Halichoerus grypus), at a mainland UK colony., Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/11373/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 Identifying the effects of anthropogenic disturbance on the breeding behaviour of female grey seals (Halichoerus grypus), at a mainland UK colony. Amy Holt Thesis submitted for the degree of Master of Science (by research) School of Biological and Biomedical Sciences Durham University 2015 1 ABSTRACT The study aimed to identify whether anthropogenic stimuli constituted a disturbance, as indicated through behavioural responses of the female grey seals (Halichoerus grypus) at Donna Nook, a mainland UK breeding colony. The colony has public access to it, and is adjacent to the Ministry of defence training range with frequent fly-overs from low flying aircraft. Data collection was non-intrusive, using in-field focal videos, proximity maps, and human activity data collection. The primary aims of the study were to identify what sources of anthropogenic disturbances, if any, effect grey seal breeding behaviour on the colony. In addition to this the study wished to observe what affect pup sex and pupping location within the colony had on breeding behaviour and individual responses to disturbance. The results of this study were in agreement with prior studies on pinniped species, indicating a very limited behavioural response of individuals to anthropogenic disturbance stimuli during the breeding season. Pedestrian disturbances had a greater impact on the behaviour of individuals than aircraft disturbances; and of all the pedestrian disturbances found at the site, photographers elicited the greatest behavioural response in individuals. Behavioural responses to disturbances were noted to be more significant over the first two minute interval after a disturbance event than over longer periods of time. In vigilance behaviours, consistent individual differences (CIDs) in an individual’s response to disturbance events were noted both across AND within disturbance contexts. Pup sex and the location of the birthing site both seemed to affect a female’s response to a disturbance event; with mothers of male pups and those females which gave birth close to the Ministry of Defence site showing significantly higher levels of vigilance behaviours after a disturbance event. Comparisons of individual responses to natural and anthropogenic disturbances revealed that individuals show a greater behavioural response to natural disturbances than those disturbances originating from a human source. The lack of behavioural responses to both natural and anthropogenic disturbance sources in the colony indicates the potential role of habituation and/or selection for behavioural types within the colony. The results of this study highlight the scope for future research into the stability of these responses to disturbance stimuli; both over numerous breeding seasons and also in periods outside of the breeding season. 2 DECLARATION OF COPYRIGHT I confirm that no part of the material presented in this thesis has previously been submitted by me or any other person for a degree in this or any other university. In all cases, where it is relevant, material from the work of others has been acknowledged. The copyright of this thesis rests with the author. No quotation from it should be published without the author’s prior written consent and information derived from it should be acknowledged. Amy Holt School of Biological and Biomedical Sciences Durham University 2014 3 Contents Page ABSTRACT .................................................................................................................................... II DECLARATION OF COPYRIGHT .................................................................................................... III LIST OF CONTENTS ...................................................................................................................... IV LIST OF TABLES ........................................................................................................................... VII LIST OF FIGURES ........................................................................................................................ VIII ACKNOWLEDGEMENTS ................................................................................................................ X REFERENCES ............................................................................................................................. 166 1. INTRODUCTION 11 1.1 Ecotourism ........................................................................................................................... 11 1.2 Types of disturbance ............................................................................................................ 13 1.2.1 Sensory cues...................................................................................................................... 19 1.3 The generalised impacts of disturbance on animal taxa ...................................................... 20 1.3.1 Mitigation measures ......................................................................................................... 21 1.3.2 Habituation and sensitisation to disturbance events ........................................................ 21 1.4 How one measures an animals response to a disturbance event ........................................ 24 1.5. Species and individual response variations to disturbance events ..................................... 26 1.5.1 Breeding context ............................................................................................................... 26 1.5.2 Intrinsic differences between individuals within a population .......................................... 28 1.6. Why is it important to study the effects of disturbance in marine mammals? ................... 32 1.7 Why choose pinnipeds to study disturbance? ...................................................................... 36 1.8 Why choose grey seals to study disturbance?...................................................................... 36 1.9 Maternal behaviour and the factors which affect it ............................................................. 37 1.9.1 Maternal characteristics and state dependent factors ..................................................... 39 1.9.2 Pup gender ........................................................................................................................ 40 1.9.3 Environmental context ...................................................................................................... 41 1.9.4 Evidence for behavioural consistency amongst grey seals ................................................ 42 1.9.5 The behavioural ecology of grey seals on a breeding colony ............................................ 43 1.10 Study Aim ........................................................................................................................... 44 1.10.1 Specific research questions ............................................................................................. 45 4 2. METHODS 46 2.1 Introduction ......................................................................................................................... 46 2.2 The study site ....................................................................................................................... 46 2.2.1 Donna Nook, Lincolnshire ................................................................................................. 46 2.2.2 The site and research into anthropogenic disturbances ................................................... 47 2.2.3 Observation dates and location ........................................................................................ 50 2.3 Field identification techniques ............................................................................................. 50 2.3.1 Female identification ........................................................................................................ 50 2.3.2 Pup stage classification ..................................................................................................... 52 2.3.3 Pup sex determination ...................................................................................................... 54 2.4. Data collection protocols .................................................................................................... 55 2.4.1 Focal videos ......................................................................................................................