Thesis and Paper IV
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Predicting decline of threatened species, invasiveness of alien species, and invasibility of semi- natural habitats: A case study from threatened coastal heathlands and semi-natural grasslands in western Norway Jan Håkon Vikane Thesis for the Degree of Philosophiae Doctor (PhD) University of Bergen, Norway 2019 Predicting decline of threatened species, invasiveness of alien species, and invasibility of semi-natural habitats: A case study from threatened coastal heathlands and semi-natural grasslands in western Norway Jan Håkon Vikane ThesisAvhandling for the for Degree graden of philosophiaePhilosophiae doctorDoctor (ph.d (PhD). ) atved the Universitetet University of i BergenBergen 2017 Dato for disputas: 1111 © Copyright Jan Håkon Vikane The material in this publication is covered by the provisions of the Copyright Act. Year: 2019 Title: Predicting decline of threatened species, invasiveness of alien species, and invasibility of semi-natural habitats: Name: Jan Håkon Vikane Print: Skipnes Kommunikasjon / University of Bergen Department of Biological Sciences, University of Bergen i ii Predicting decline of threatened species, invasiveness of alien species, and invasibility of semi- natural habitats: A case study from threatened coastal heathlands and semi-natural grasslands in western Norway Dissertation for the degree of Philosophiae Doctor (PhD) Jan Håkon Vikane Department of Biological Sciences Faculty of Mathematics and Natural Sciences University of Bergen, Norway 2019 Advisors: Prof. Vigdis Vandvik, University of Bergen Prof. Ole Reidar Vetaas, University of Bergen iii Contents Acknowledgements ............................................................................................. v List of publications ............................................................................................ vi Declaration ........................................................................................................ vii Abstract ............................................................................................................... 1 Introduction ......................................................................................................... 4 Objectives ........................................................................................................... 7 Target species and study systems ....................................................................... 8 Picea sitchensis .............................................................................................. 8 Arnica montana ............................................................................................ 12 Pinus sylvestris ............................................................................................. 14 Pinus mugo. .................................................................................................. 16 Study system: Coastal heathlands ................................................................ 18 Study system: Semi-natural grasslands ........................................................ 20 Methods ............................................................................................................ 22 Paper I ........................................................................................................... 22 Paper II ......................................................................................................... 24 Paper III ........................................................................................................ 27 Paper IV ........................................................................................................ 28 Results and discussion ...................................................................................... 30 Dispersal as a driver to changes in distribution and abundance ................... 30 Disturbance as a driver to changes in distribution and abundance ............... 31 Linking environmental drivers and population growth rate ......................... 33 Impact from increasing abundance of non-native species ............................ 35 Conclusions and perspectives ........................................................................... 37 Acknowledgments ............................................................................................ 38 References ......................................................................................................... 39 Papers ................................................................................................................ 50 iv Acknowledgements First, I would like to say thank you to my supervisors, Vigdis Vandvik and Ole Reidar Vetaas. Vigdis has followed me since I knocked on her office door in 2005 and asked her if she would like to be my supervisor on my master thesis. Together we designed the Arnica study, which has become a part of this PhD-thesis. Thank you for always supporting me, and for never to lose faith in me during all these years. Thank you to Ole Reidar for giving me the opportunity to become a part of the Invaliens project and thank you for letting me leave my mark on the project, be open to my ideas and for your support. I would also like to thank Knut Rydgren which has been a good co-author in two papers, thank you for always being so positive and supportive. Also, thank you to Eelke Jongejans for sharing your analytic skills and for your good support in two papers. I have also appreciated the good cooperation with my PhD-colleague, Heidi Iren Saure, we have had good discussions and you have been a good company at the office and in the student canteen. I would also like to thank Solveig Stentvedt and Rebecca Smith for assistance with field work, your practical knowledge has been appreciated. Also thank you to Marta Ramírez Boixaderes for being patient with the tedious work of counting seeds in seed traps. Thanks to colleagues at the University of Bergen and to colleagues at Volda University College for good company and support. Last, but not least I would like to say thank you to my family for always asking me when I would finish my thesis, so I never forgot the goal. v List of publications This thesis is based on four following papers which will be referred by their roman numerical hereafter. Paper I Vikane J. H., Rydgren, K., Jongejans, E. & Vetaas, O. R. (2019). Spread of Picea sitchensis from plantation into adjacent coastal heathland. Manuscript Paper II Vikane, J. H., Rydgren, K., Jongejans, E. & Vandvik, V. (2019). Rainfall and temperature change drive Arnica montana population dynamics at the Northern distribution edge. Oecologia. In press. Paper III Vikane, J. H., Vandvik, V., & Vetaas, O. R. (2013). Invasion of Calluna heath by native and non-native conifers: the role of succession, disturbance and allelopathy. Plant ecology, 214 (7), 975-985. Paper IV Vetaas, O. R., Vikane, J. H., Saure, H. I., & Vandvik, V. (2014). North Atlantic Islands with native and alien trees: are there differences in diversity and species‐area relationships? Journal of Vegetation Science, 25 (1), 213-225. Paper III and IV are reprinted with permission from the publishers. vi Declaration Paper I: Vikane J. H, Rydgren, K., Jongejans, E. & Vetaas, O. R. (2019). Natural regeneration of Picea sitchensis from plantation into adjacent coastal heathland. Vikane, J. H: Study design, collected data, analysed data, wrote the paper. Rydgren, K: Study design, inputs on analytical design, editing Jongejans, E: Analysed data, inputs on analytical design, editing Vetaas, O.R: Project design, study design, editing Paper II: Vikane, J. H. Rydgren, K., Jongejans, E. & Vandvik, V. (2019). Rainfall and temperature change drive Arnica montana population dynamics at the Northern distribution edge. Vikane, J. H: Study design, collected data, analysed data, wrote the paper Rydgren, K: Analysed data, inputs on analytical design, editing Jongejans, E: Analysed data, inputs on analytical design, editing Vandvik, V: Study design, editing Paper III: Vikane, J. H., Vandvik, V., & Vetaas, O. R. (2013). Invasion of Calluna heath by native and non-native conifers: the role of succession, disturbance and allelopathy. Plant ecology, 214(7), 975-985. Vikane, J.H: Study design, collected data, analysed data, wrote the paper Vandvik, V: Study design, inputs on analytical design, editing Vetaas, O.R.: Project design, study design, analysed data, editing Paper IV: Vetaas, O. R., Vikane, J. H., Saure, H. I., & Vandvik, V. (2014). North Atlantic Islands with native and alien trees: are there differences in diversity and species‐area relationships? Vetaas, O. R.: Project design, study design, collecting data, analysed data, wrote the paper Vikane, J.H: Study design, collecting data, editing Saure, H.I: Study design, collecting data, editing Vandvik, V: Study design, input on analytical design, edit vii Abstract Semi-natural habitats are characterised by a large biodiversity, but also associated with a large susceptibility to invasion by non-native species. Coastal heathlands and semi-natural grasslands in Norway, are under pressure from many different drivers, like invasion of non-native species, fragmentation, intensification and currently climate change, leading to concern about the cumulative effects from multiple global change drivers. Success of a non-native species in a new environment and a native species in a changing environment would be dependent on the tolerances to any changes in abiotic and biotic conditions. Thus, to make predictions about potentially invasion