Thèse de Doctorat Mention Sciences écologiques Spécialité Ecologie, Evolution et Biodiversité présentée à l'Ecole Doctorale en Sciences Technologie et Santé (ED 585) de l’Université de Picardie Jules Verne par ALI ALMOUSSAWI pour obtenir le grade de Docteur de l’Université de Picardie Jules Verne Importance relative des processus de dispersion et de recrutement dans la dynamique d’assemblage des communautés végétales en paysage agricole Soutenue le 06 Septembre 2019, après avis de rapporteurs, devant le jury d’examen : Mme Sophie Nadot, Professeur (Université Paris-Sud 11) President me M Estelle Forey, Maître de Conférences HDR (Université du Rouen) Rapporteur M. Michel-Pierre Faucon, Maître de Conférences HDR (UniLaSalle) Rapporteur M. Fréderic Dubois, Professeur (UPJV) Examinateur M. Guillaume Decocq, Professeur (UPJV) Directeur M. Jonathan Lenoir, Chargé de Recherche CNRS-UPJV Co-encadrant PhD Thesis Ecological Sciences Ecology, Evolution and Biodiversity Presented for The Doctoral School in Science, Technology and Health (ED 585) Of the University of Picardie Jules Verne By ALI ALMOUSSAWI To obtain the degree of Doctor from the University of Picardie Jules Verne Dispersal limitation vs recruitment limitation in local assembly rules of plant communities within agricultural landscapes Defended on 06 September 2019, after the review of the reviewers and in front of the examination Board: Mme Sophie Nadot, Professor President me M Estelle Forey, Assistant Professor Reviewer M. Michel-Pierre Faucon, Assistant Professor Reviewer M. Fréderic Dubois, Professor Examiner M. Guillaume Decocq, Professor Director M. Jonathan Lenoir, Senior Researcher Co-director This thesis was prepared within the research unit “Ecologie et Dynamique des Systèmes Anthropisés” EDYSAN, UMR CNRS 7058, 1 rue des Louvels 80037 Amiens Cedex إلى أمي وأبي........ إلى أخوتي حسين وﻻء فاطمة محمد.......... إلى قطعتي قلبي عباس وعلي............ “Rise and rise again and again like the Phoenix from the ashes; until the lambs have become lions.” ― Maitreya Acknowledgements At the end of three astonishingly unforgettable years, I would like to thank everyone who contributed in one way or another to the success of this work. First and foremost, I would like to thank the jury members for accepting to evaluate this work. I would like to express my sincere gratitude to my Director, Prof. Guillaume DECOCQ, for giving me the chance to work on this project. Your enthusiasm and encouragement in good times and in bad will always be appreciated. Thank you for inspiring my research and allowing me to grow as a scientist. Had it not been for your patience and those numerous discussions, I would not have been as fortunate to be where I am today. Simply, if it were not for you, I would not have had the chance to embark on this journey and experience the sweet taste of fruitful efforts. In other respects, I would like to express my profound appreciation for my co-director Dr. Jonathan LENOIR, or as I like to call him “BOSS”. I am deeply and eternally grateful for the tremendous amount of time and effort you have put into this project. Although it was never easy working with the perfectionist within you, I am honestly thankful for you forcing me to never accept anything less than whole. Your passion for research and your unwavering vision are truly inspiring, even contagious. With your supervision and guidance, I managed to turn the tide every single time. Your counsel has been the cornerstone I leaned on for support throughout my odyssey. I thank my luck I had the chance to work with you. For Prof. Ahmad KOBEISSI, my co-supervisor and masters coordinator, Thanks for your patience, your listening, your availability and your support without fault. You were an exceptional supervisor and without you, I would not get the chance to be a PhD student. Dr. Déborah CLOSSET-KOPP or the SHERIF ;), the kindest and most caring scientist I had ever met, I am very glad of having unforgettable moments with you being the center of every event. Thank you for your encouragement and unlimited kindness. I would like to thank Dr. Naim BOUSTANY and Dr. Zeinab ASSAGHIR for their continuous support and you were always believing in me. It is a chance for me to gift you my efforts in this report and to express for you my gratitude for being a part of this success. What I have been vainly trying to convey with words does not come close to expressing the amount of admiration I hold for all four of you. I genuinely cannot find enough words to thank you as I must and you deserve. My heartfelt thanks go to Emilie GALLET-MORON-Moron (the kindest person you can ever meet on this planet), and I would like to tell you that you were a symptom of optimism in my life during all my stay at GEP. Fabien SPICHER, or the botanist with no limits and the mobile botanical library, I would like to thank you for all your efforts in helping me during the fieldwork, lab work and analysis. I would like to show a big thank to all the permanent staff, doctoral students, trainees and secretary and to the former colleagues whom I was able to work with during my thesis and who contributed to the good atmosphere that prevails at EDYSAN: Lamine (My brother) thank you for your encouragement and help when I needed it! Thank you for all the discussions, first of all, professionals, who opened up to me many new doors, as well as for our long discussions and debates about different topics. Tarek (or the ARTIST) thank you for launching me in this world of R. Thanks also to my office mates: Olivia; Pedro; Benoit; Camille; Mederic; Vincent; Sabrina; Marine; Aude; and Arnaud. I wish to thank Frédéric BERQUIN for all administrative procedures. I have really bothered you a lot with my questions. Olivier, Hélène, Boris, Sylvie, Jérôme, Frédéric, and Alexandre: thank you all for everything. I would also like to thank all the co-authors of the various projects for their very valuable comments, their motivations and encouragement. I especially want to thank Aurélien, Safaa and Carol. Many thanks to all the other members of the research unit. My sincere thanks are addressed first to Prof. Frédéric DUBOIS (for allowing me to work at the UFR science and allowing me to borrow the screen and for being a member of my thesis committee), and Prof. Arnaud AMELINE (for allowing me to use stereoscopes during seed preparation). Thank you all the members of the EDYSAN research unit who are so numerous and I am not going to name you all, but you will recognize yourselves. During my stay in Amiens, I was also fortunate to make many friends from Amiens and outside France. I am glad I met each and every one of you guys: Abdel-Rahman, Khaled, Johanna, Afaf, Ranim, Douaa, Soukaina, Layal, Ghaya, Maya A, Maya, Rosa, Kareem, Fatima, Rana, Abbass, Walaa, Hussein, Ahmad, Hawraa N., Ihsan, Tarek, Nisrine, Sami, Hiba S., Leila, Zakaria, Hawraa A. Jeanne, Hawraa I., Zeinab, Fayez, Manar, Ali T., Ali N., Ali M. All of you were there since day one, supporting and helping me in every way possible, and thank you for your encouragement, compassion, and the times we spent arguing and discussing ideas, and I hope you all reach what you are aiming for. Louay & Reya I treasure your kindness and the way you care about others, it is truly heart-warming. Hamza, it is said that true friends are never of the same height, which is the case with me and you but be happy that we share the passion for food. This has brought us even closer as friends and guaranteed that we always have something to talk about. Ali J. Thank you for being the brother that I can count on during my whole stay in Amiens, and for being my first guide in every problem I had faced in France. You were the ace in every situation and not just for me but for all the Lebanese students. May God Keep your spirit high and may your wishes (what we share) come true DOCTOR ALI ;). I was also blessed to have friends outside the lab, amazing people with whom I shared countless moments and being more like family than friends: Mohammad A., Ali C, Ali J. Mahmoud, Mohammad R., Majd R. Nassim, Issam, Mohammad N., Khaled, Azad, Assi, Amar H., Alaa M. I am grateful to have you as a cousin and as a BIG brother AMYSM where I fearlessly chased all my BIG dreams knowing that my BIG brother will always look out for me. I will never be able to be a BIG bro to you but the least I can do is start by saying a BIG ‘Thank You’. To the people who never believed in me, who thought I was not good enough to have any chance to be successful without their presence. I have to thank you because proving you wrong has been my greatest incentive. Thanks again for providing me with the challenge I set out to conquer. To my family, the people who never stopped believing in me; thank you for the unconditional love and support. To my grandparents, aunts and uncles with whom I grew up, thank you for instilling in me compassion, forgiveness and the love for others, for making me believe that the best way to predict the future is to create it myself, and that education makes the possibilities endless. Finally, to my parents, brother and my little angel (Loulou), mere words cannot begin to unravel how much you mean to me, but I promise to not let you down and to always be by your side whenever needed.