Developing Tools for the Management of Freshwater Crayfish
Total Page:16
File Type:pdf, Size:1020Kb
- 1 - Developing Tools for the Management of Freshwater Crayfish Stephanie Peay Submitted in accordance with the requirements for the degree of Doctor of Philosophy The University of Leeds Faculty of Biological Sciences September, 2013 - 2 - The candidate confirms that the work submitted is her own, except where work which has formed part of jointly-authored publications has been included. The contribution of the candidate and the other authors to this work has been explicitly indicated below. The candidate confirms that appropriate credit has been given within the thesis where reference has been made to the work of others. Chapter 2 is from the following jointly-authored paper: Peay S., Holdich D. M. and Brickland J. (2010). Risk assessments of non-indigenous crayfish in Great Britain. Freshwater Crayfish, 17 109-122 Contributions of each author: Stephanie Peay carried out a literature review and the risk assessments for Pacifastacus leniusculus and Procambarus clarkii and wrote most of the paper. David M. Holdich carried out risk assessment for Orconectes limosus contributed to the introduction and reviewed and edited. Jonathan Brickland carried out risk assessments for Astacus astacus and A. leptodactylus. Chapter 3 is from the following jointly-authored paper: Peay, S., Guthrie, N., Spees, J., Nilsson, E. and Bradley, P. (2009). The impact of signal crayfish (Pacifastacus leniusculus) on the recruitment of salmonid fish in a headwater stream in Yorkshire, England. Knowledge and Management of Aquatic Ecosystems 394-395. DOI: 10.1051/kmae/2010003. Contributions of each author: Stephanie Peay designed the study, carried out the crayfish survey, helped with some of the fisheries survey, analysed the data and wrote the paper. Neil Guthrie was the project manager for the Environment Agency, which funded part of the work and he helped to edit the paper. Jack Spees carried out the fisheries survey work in 2008 and provided comparative data on the substrates and helped to edit the paper. Erika Nilsson carried out the fisheries survey in 2007 and helped to edit the paper. Paul Bradley provided information on the original introduction and first detection of crayfish invasion. - 3 - Chapter 8 was the basis for a sole-author paper that appeared as: Peay, S. (2009). Selection criteria for “ark sites” for white-clawed crayfish. pp. 63-70, In: Brickland, J., Holdich, D. M. and Imhoff, E. M. Crayfish conservation in the British Isles. Proceedings of a conference held on 25th March 2009 in Leeds, UK. http://iz.carnegiemnh.org/crayfish/IAA/docs/2009_Crayfish_Conservation_in_the_Brit ish_Isles_LR.pdf Chapter 9 was the basis for a sole-author paper that appeared as: Peay, S. (2011). Developing conservation strategy for the white-clawed crayfish at catchment scale in England and Wales – a way forward? pp. 23-44, In: Rees, M. Nightingale, J. and Holdich, D. M. (Eds.). Species Survival: securing white-clawed crayfish in a changing environment. Proceedings of a conference held on 16th and 17th November 2010 in Bristol, UK. http://www.bcsf.org.uk/sites/default/files/files/Rees%20et%20al_%202011%20(2010 %20crayfish%20conference,%20high%20resolution%20version%20available%20on %20request_).pdf - 4 - Acknowledgements I would like to thank my supervisors Alison Dunn and Bill Kunin from the School of Biology at the University of Leeds, who have provided me with much useful guidance on research. I thank David Holdich (University of Nottingham) and Pete Hiley (URS) who have been mentors to me on freshwater crayfish, before and during the period of this research, and to Julian Reynolds (Trinity College Dublin), Catherine Souty- Grosset (University of Poitiers) and Francesca Gherardi (University of Florence), who have also provided me with support and guidance. I have worked with many other people, who have contributed, advice, companionship and fieldwork. I would like to thank Colin Bean (Scottish Natural Heritage), without whom none of the work on crayfish eradication methods in Scotland would have happened. Thanks go to all the project managers, staff, volunteers landowners and agencies who contributed to the biocide projects (see Chapter 4). Thanks go to Jack Spees (Ribble Catchment Conservation Trust), Robin McKimm (Electrofishing Services Ltd), Paul Bradley (Paul Bradley Associates) for their involvement in the Ribble catchment, in this study and other work. Thanks go to Vicky Kindemba, Andrew Whitehouse and Kate O’Neill (Buglife) and others who helped set up and subsequently run the Crayfish UK website. Thanks go to all the landowners who gave consent for field work and to the colleagues, volunteers, friends and fellow students who have supported me in various ways. My employers, URS, allowed me work on a part-time basis so I could spend more time on my research. I am very grateful to my parents for their support, especially my late father, who started my fascination with biology. Above all, thanks go to my husband Paul Bryden, who has provided support to me throughout. He has provided many long hours of fieldwork as a volunteer on a range of projects, provided use of his workshop and practical skills, maintained invaluable IT support, put up with my irregular hours and has provided so much care and encouragement to me throughout the 16 years I have been working with crayfish. - 5 - Abstract The introduction of non-indigenous crayfish into Europe is causing the loss of indigenous crayfish, due to transmission of crayfish plague and competition. Other factors are reductions of habitat quality and in some areas harvesting. This study deals with issues facing environmental agencies and other resource managers about how manage crayfish; from prevention of further introductions, to eradication where feasible, or control if it is cost-effective, or where it is not, then applying measures to mitigate the effects of invasion by finding or establishing isolated areas for indigenous crayfish, i.e. ark sites. It provides a range of decision-making tools for management. The study includes a literature-based risk assessment for non- indigenous crayfish in Great Britain. It presents the first evidence of the negative impact of signal crayfish Pacifastacus leniusculus on salmonid fish in a headwater stream. The study shows how the technique of biocide treatment against signal crayfish has developed, the outcomes and the lessons learned from the projects and factors that will contribute to other successful eradication treatments in future. Another new potential method for eradication or control is electric shock treatment, which was field-tested in this study. As an aid to assessing the feasibility of eradication or control, a simple cost-model was developed using the potential impact on salmonid fish and a re-stocking cost as a surrogate for environmental impact of crayfish invading a catchment. This was used to compare the costs of eradication or control and showed the benefit of early eradication and the unsustainably high cost of control by trapping. As signal crayfish are already widespread in England and Wales, risk-based selection criteria were developed to help identify potential ark sites for white-clawed crayfish. In addition, a decision-making tool has been prepared to help conservation managers understand the issue and develop conservation action plans at catchment scale. - 6 - Table of Contents Acknowledgements ..................................................................................... 4 Abstract ........................................................................................................ 5 Table of Contents ........................................................................................ 6 List of Tables ............................................................................................. 11 List of Figures ........................................................................................... 13 Chapter 1 Introduction: biological invasion and management tools .... 17 1.1 Biological invasions ...................................................................... 17 1.2. Biological invasions by crayfish .................................................... 22 1.3 Impact of invasive crayfish on indigenous crayfish ....................... 26 1.4 Assessing risk of invasive crayfish ............................................... 30 1.5 Eradication and control of invasive crayfish ................................. 31 1.5.1 Mechanical removal .......................................................... 31 1.5.2 Physical methods of control .............................................. 33 1.5.3 Chemical methods ............................................................ 34 1.5.4 Biological methods ............................................................ 36 1.6 Conservation of indigenous crayfish............................................. 39 1.7 Overview of thesis ........................................................................ 40 1.7.1 Part 1 Invasion ecology: risks and impacts of non-indigenous crayfish ................................................................................ 40 1.7.2 Part 2 Eradication and control of invasive crayfish ........... 41 1.7.3 Part 3 Conservation management for indigenous white-clawed crayfish ................................................................................ 43 Chapter 2 Risk assessments of non-indigenous crayfish in Great Britain ............................................................................................................ 45 2.1 Introduction