Modelling frugivore-mediated seed dispersal

Seed dispersal is the movement of seeds away from parent plants, and is a crucial ecological process for plant reproduction, persistence and spatial distribution.Specic interest in frugivorous seed-dispersal has increased due to its importance for plant temporal and spatial dynamics under global change.Empirical studies conrm that the interaction between eshy-fruited plants and frugivores is mutualistic and can be fully benecial for both partners provided that the dispersal cost is low.The animals benet is quite obvious (food) while plants benet is seed dispersal leading to reduced level of plant aggregation among other benets.Based on pair-approximation method, we here propose a process-based mechanistic model of frugivorous seed-dispersal that captures the dynamics of the global and local densities of plants and the density of frugivores.The model considers three essential components of frugivorous seed-dispersal, including the strength of plant-frugivore mutualistic interaction, dispersal eciency of frugivores and germination probability of seeds.Our theoretical ndings agree with previous empirical studies that seed dispersal decreases plant intraspecic competitions by reducing the level of plant clustering.Results show that ecient frugivorous animals allow conditional persistence of plants with low fecundity and natural dispersal ability.Otherwise, inecient animal seed-dispersers, with high dispersal risks, will act as seed predators, leading to global extinction of plants.Finally, results show the animals benet (increased density equilibrium of animals) from plant-frugivore mutualistic interaction.Interestingly, our results provide broad theoretical evidence for the paramount importance of the existence of furgivore species in tropical forests.I am very grateful to my supervisor Professor Cang Hui for his continuous encouragement, profound support, fruitful discussions and kind treatment with nice smiles.You taught me not only the essential research skills but also how to become an independent researcher.Special thanks and appreciation for my co-supervisor, the very kind and wonderful person, Dr. Pietro Landi for his great and valuable discussions and for teaching me many things, including the analysis of the basic ecological models, bifurcation analysis, MATCONT, adaptive dynamics, etc.I will be indebted to you forever.I would like to equally express my thanks and appreciation for Dr. Henintsoa Onivola Minoarivelo for her valuable discussions and continuous support during the project.I am very grateful to you.Without those people, this project would have never been done.I greatly acknowledge the eorts made by all of them to nish this project.It is my pleasure to thank the Mathematical Sciences Departmental secretary and our team's assistant Mrs. Vanessa Du Plessis for her help and kind communications before and during my M.Sc.studies.Thank you very much Vanessa for arranging our meetings with Prof. Cang, and processing my bursaries.I will never forget your profound help in facilitating my travel to attend a summer