Movement Behaviour And Seed Dispersal Patterns Of Trumpeter Hornbills (Bycanistes bucinator) In Fragmented Landscapes Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften vorgelegt beim Fachbereich Biologie der Johann Wolfgang Goethe-Universität in Frankfurt am Main von Johanna Lenz aus Wiesbaden 1. Fassung: Frankfurt 2012 2. Fassung: Frankfurt 2013 (D 30) vom Fachbereich Biologie der Johann Wolfgang Goethe-Universität als Dissertation angenommen. Dekanin: Prof. Dr. Anna Starzinski-Powitz Erste Gutachterin: Prof. Dr. Katrin Böhning-Gaese Zweiter Gutachter: Prof. Dr. Oliver Tackenberg Datum der Disputation: 19. Dezember 2013 To my father. “Remember that the best relationship is one in which your love for each other exceeds your need for each other.” Dalai Lama 2004 Illustrations by Gabriele Lenz © CONTENT 1 Summary..........................................................................................................................................1 2 General Introduction.......................................................................................................................3 Biodiversity, human well-being and ecosystem functions...............................................................3 Habitat fragmentation as threat to biodiversity in tropical forests...................................................6 Seed dispersal..................................................................................................................................7 Animal-mediated long-distance seed dispersal..............................................................................10 Factors affecting movements of seed-dispersing birds..................................................................11 Measuring seed dispersal...............................................................................................................12 Tracking seed dispersal across spatial and temporal scales...........................................................16 Aims and structure of the thesis.....................................................................................................17 3 Seed dispersal Distribution of Trumpeter Hornbills in a Fragmented Landscape.................21 3.1 Abstract....................................................................................................................................22 3.2 Introduction..............................................................................................................................22 3.3 Materials and Methods.............................................................................................................24 3.3.1 Study site and species......................................................................................................24 3.3.2 Trapping and tracking of Trumpeter Hornbills................................................................25 3.3.3 Feeding trials....................................................................................................................26 3.3.4 Data analysis....................................................................................................................27 3.4 Results......................................................................................................................................29 3.5 Discussion................................................................................................................................34 3.6 Acknowledgement...................................................................................................................37 4 Processes of Seasonal Range Expansion of a Large Frugivorous Bird.....................................39 4.1 Abstract....................................................................................................................................40 4.2 Introduction..............................................................................................................................40 4.3 Methods...................................................................................................................................42 4.3.1 Study area.........................................................................................................................42 4.3.2 Study species....................................................................................................................43 4.3.3 Trapping and tracking......................................................................................................43 4.3.4 Data Analysis...................................................................................................................44 4.5 Results......................................................................................................................................47 4.6 Discussion................................................................................................................................51 4.7 Acknowledgement...................................................................................................................55 5 Large Frugivorous Birds Facilitate Functional Connectivity of Fragmented Landscapes....57 5.1 Abstract....................................................................................................................................58 5.2 Introduction..............................................................................................................................59 5.3 Methods...................................................................................................................................61 5.3.1 Study area and habitat......................................................................................................61 5.3.2 Hornbill movement and gut passage time........................................................................62 5.3.3 Frequency and limitation of between-patch dispersal......................................................62 5.3.4 Functional connectivity and mapping dispersal pathways...............................................63 5.4 Results......................................................................................................................................64 5.5 Discussion................................................................................................................................71 5.5 Acknowledgements..................................................................................................................74 6 General Discussion........................................................................................................................75 Meet the challenge of measuring long-distance seed dispersal.....................................................76 Variability of seed dispersal function in space and time................................................................77 From seed dispersal kernel to spatially explicit connectivity measures........................................81 Seed deposition-site and plant recruitment success.......................................................................82 Seed shadows are teamwork..........................................................................................................84 Narrowing the gap in long-distance seed dispersal research.........................................................85 7 Zusammenfassung.........................................................................................................................87 7.1 Muster der Samenausbreitung durch Trompeter Hornvögel in einer fragmentierten Landschaft......................................................................................................................................89 7.2 Saisonale Streifgebietserweiterung eines großen frugivoren Vogels.......................................90 7.3 Große frugivore Vögel ermöglichen eine funktionale Konnektivität innerhalb fragmentierter Landschaften..................................................................................................................................91 8 References.......................................................................................................................................92 9 Acknowledgements......................................................................................................................106 10 Appendices..................................................................................................................................109 Appendix 1: Seed dispersal kernel for 10 individuals.................................................................109 Appendix 2: Measurement error for GPS data loggers................................................................110 11 Curriculum Vitea.......................................................................................................................111 Summary 1 SUMMARY Long-distance seed dispersal is a crucial process allowing the dispersal of fleshy-fruited tree species among forest fragments. In particular, large frugivorous bird species have a high potential to provide inter-patch and long-distance seed transport, both important for maintaining fundamental genetic and demographic processes of plant populations in isolated forest fragments. In the face of increasing worldwide forest fragmentation, the investigation of long-distance seed dispersal and the factors influencing seed dispersal processes has recently become a central issue in ecology.