The Role of Behavioural Changes in Biological Invasions
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The Role of Behavioural Changes in Biological Invasions Inaugural-Dissertation to obtain the academic degree Doctor rerum naturalium (Dr. rer. nat.) submitted to the Department of Biology, Chemistry and Pharmacy of Freie Universität Berlin by Florian Ruland 2019 DECLARATION The scientific work presented in this thesis was conducted from October 2014 to December 2019 at the Institute of Biology (FU) and the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin, Germany. The work was supervised by Prof. Dr. Jonathan M. Jeschke, head of the Ecological Novelty group at FU and IGB. Dr. Max Wolf, head of the Causes and Consequences of Behavioural Types group at IGB was co-supervisor. 1. Gutachter: Prof. Dr. Jonathan Jeschke 2. Gutachter: Prof. Dr. Britta Tietjen Disputation am: 30.04.2020 ACKNOWLEDGEMENTS ACKNOWLEDGEMENTS I am thankful towards all people who made this thesis possible. First and foremost, I want to thank Jonathan Jeschke for his supervision. His trust in the project and me allowed me to freely research, study and learn. I consider myself lucky to have found a supervisor with such an open mind, who has not narrowed down but expanded his curiosity over the course of his professional life. I also want to thank my second supervisor Max Wolf who is always up for an open and explorative discussion. The work group Ecological Novelty has been a great support and hosts a number of people who have become dear friends. I thank the summer swimming crew. I thank the scavenging team. Especially I want to thank Judith Niedersen for adventures in- and outside of the university. I want to thank Federico Castro Monzon to be there in dark moments and turning them into hope and fun. And for being the most competitive swimming partner I ever had. I want to thank Stefan Linzmaier for the fun and privilige to join his bachelor's weekend, which started our enduring friendship. I want to thank Martin Enders for introducing me to animal ethics and becoming vegan with me. I want to thank Camille Musseau and Alban Sagouis for moving to Berlin and let our friendship that started in Toulouse continue. I want to thank Maud Bernard- Verdier for statistical advice and the honest and mind-opening debates. Thanks to all my bachelor- and master students. Their work and questions was inspiring and saved me from mistakes quite a few times and some have become good friends over the last years: Mariela Saldias Collao, Daniel Kammholz, Timon Koths, Vanessa Melcher, Andreas Meltl, Muriel Neugebauer, Yari Osenberg, Fiona Rickowski, David Stille, Beatrice Wolf, Sally Wolff. Many thanks to my friends in Iceland, Menja von Schmalensee, Róbert Stefánsson and their wise, talented and cool children. Their hospitality was incredible, I cherish our time together. It is important to mention professor Horribilus, who sparked the flame of curiosity in my childhood. I want to thank the Ziege flat, which has supported me and has been my haven in Berlin as well as a source of truly random adventures. Finally, I want to thank my family for making me a person that writes a dissertation in Ecology. They raised me with a respect for nature and to approach the world with curiosity. IV "There are reasons to believe, behavioural shifts have been involved in most evolutionary innovations, hence the saying that behaviour is the pacemaker of evolution." Ernst Mayr (What Evolution is. 2001) V SUMMARY SUMMARY All ecosystems on Earth are undergoing rapid human-induced changes. One important component of these changes is the transport of species to new ecosystems, where they often establish and spread, and cause ecological disruption as invasive species. Behaviour plays a major role in this process, not only by enabling species to spread or establish, but also in the native species’ response to invasion. These behavioural changes drive population dynamics, and the speed at which they happen are crucial. The shared evolutionary history between two species influences how fast or effective these changes happen. To study these complicated interactions, this thesis combines a comparative study of the existing literature with novel concepts and metadata, as well as analyses of laboratory experiments and field data. For Chapter 1, a large cross-taxonomical dataset on behavioural changes in biological invasions was gathered and analysed. It is the first to include native and non-native species, to identify types of behaviour and mechanisms of change and to quantify the speed of the behavioural change. This gave us the opportunity to test hypotheses in invasion ecology, but also to explore the distribution of learning across types of behaviour and its implications for the speed of behavioural change. All analyses were conducted considering the biases in the data and differences in the ecology of native and invasive species. In Chapter 2, the behavioural differences between an established non-native crayfish species, the spiny- cheek crayfish Faxonius limosus, and the novel non-native marbled crayfish (Procambarus virginalis) were experimentally quantified, and findings were used to predict the invasion success of the latter species. Experiments were designed to show the outcome of inter-specific agonistic interactions, activity and exploration. Finally, not only inter-specific differences were tested but also between both sexes of the spiny- cheek crayfish, and between lab-reared and wild-caught individuals of the marbled crayfish. Apart from predicting invasion success, these analyses help to better understand behavioural plasticity in this special clonal species. Chapter 3 contains the application of two classification schemes - of animal innovation and eco- evolutionary experience - to the dataset of Chapter 1. I encourage the use of this general quantification scheme of animal innovation to mine a broader range of behavioural changes. The scheme was applied in this study to specifically investigate if big changes in behaviour help native species to cope with invasion. It was also tested if high eco-evolutionary experience with that species buffers negative population consequences for native species. We reject the first hypothesis and accept the latter and found as well a negative relationship between both parameters, as lower experience necessitates bigger change. Therefore, these classifications can help a priori predictions of invasion impact on specific native species. In Chapter 4, the population dynamics and nesting behaviour of the common eider (Somateria mollissima) in West Iceland was analysed from field data. The dataset encompasses yearly nest count data on VI SUMMARY 134 islands over up to 123 years. Therefore, we were able to investigate how long-term climate dynamics affect the eider colonies and how that changed with the invasion of the American mink (Neovison vison) into the region in 1948. Similarly, the arctic fox (Vulpes lagopus), the only native terrestrial nest predator, was absent from the study area for decades and we compared the behavioural response to both predators. The differences between the effects of specific predators help to direct targeted conservation efforts to protect the common eider. Finally, Chapter 5 presents population dynamics of the American mink in Iceland, Denmark, Germany and its native range in the USA estimated from hunting bag data using a novel method. Effects of anthropogenic factors on the hunting bag were quantified, namely the global price of American mink fur, the production of fur in the respective country, and hunting effort and legislation connected to hunting and fur production. While we were able to test several hypotheses on American mink population dynamics in Europe - for example, if it follows a boom-bust dynamic - the utility of this method stretches beyond this system and can be applied whenever population numbers are estimated from hunting bag data. My thesis explores a novel dataset on behavioural changes in biological invasions (Chapter 1). It includes experimental results on the role of behaviour in an over-invasion scenario of crayfish in Europe (Chapter 2) and expands the horizon of behavioural studies in invasions by introducing classification schemes for eco- evolutionary experience and animal innovation (Chapter 3). Finally, the introduction of the American mink in Europe is studied, by its consequences for the Icelandic avifauna (Chapter 4) and the estimation of its population dynamics through hunting bag data in several countries (Chapter 5). Keywords: Behaviour, biological invasions, eco-evolutionary experience, innovation, naïveté, population dynamics VII ZUSAMMENFASSUNG ZUSAMMENFASSUNG Sämtliche Ökosysteme der Erde sind rapidem menschengemachten Wandel unterworfen, unter anderem durch Arten, die in neue Ökosysteme transportiert wurden, sich dort ansiedeln und dann verbreiten, um dabei oft erheblichen ökologischen Schaden anzurichten: invasive Arten. In diesen biologischen Invasionen spielt Verhalten eine wichtige Rolle: Verhaltensänderungen können Invasionen ermöglichen, können es heimischen Arten aber umgekehrt auch erlauben, adäquat auf invasive Arten zu reagieren. Verhaltensveränderungen können Populationsdynamiken beeinflussen; dabei ist die Geschwindigkeit, in der sie passieren, von großer Bedeutung. Diese ist wiederum davon abhängig, ob die Arten an ökologisch ählniche Arten evolutionär angepasst sind. Um diese Zusammenhänge zu erforschen, wurden in vorliegender Dissertation eine Literaturstudie mit einer konzeptionellen Studie und Analysen von Experimenten und Freilanddaten