The Effects of Human Disturbance on Vascular Epiphyte in the Brazilian Atlantic Forest
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The effects of human disturbance on vascular epiphyte in the Brazilian Atlantic Forest Edicson Parra-Sanchez Imperial College London Department of Life Science Silwood Park Campus Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) April 2018 1 “What we have to practice today is solidarity, one must not approach people to say Here we come to give the charity of our presence, to teach our science, to show you your mistakes, your ignorance, your lack of basics. We go with investigative zeal, and humble spirit, to learn in great source of wisdom which is the people.” Che Guevara 2 Declaration The data collection and work presented in this thesis is all my own. Dr Cristina Banks-Leite did provide guidance throughout my thesis. Chapters are organized as papers, and I used “we” to recognize the role of my supervisor Dr Cristina. Data sources and software are referenced along the text. The support of different people is acknowledge as follows: Data collection was done with field assistants Jordy Jerez, Manon Czuckermand and Tiago Gloria. The study design was done by ECOFOR (Biodiversity and Ecosystem Functioning in Degraded and Recovering Amazonian and Atlantic Forests). Taxa identification was done with the help of MSc Gabriel Marcusso (Piperaceae), Dr Carlos Nunes and Eric Hagsater (Orchidaceae), Ms Suzana Martins and Marcio Leofegario (Bromeliaceae), Dr Alain Chautems (Gesneriaceae), and Thomas Croat (Ferns). In chapter 2, advice on the model fitting and interpretation was provided by Dr Jack Hatfield. In chapter 3, advice on the interpretation of the n-dimension analysis was provided by Dr Thomas Guillerme (as author of the “dispRity” R package). Dr Igor Lysenko help out with the initial raster files for the analysis in BioFrag®. In chapter 4, life history traits were partly collated by Eleanor Moore and canopy openness raw data was compiled by Kate Chandler as part of their undergraduate projects at Imperial College London. Advice on the interpretation of LMM models was provided by Dr Jack Hatfield. 3 Copyright Declaration The copyright of this thesis rests with the author and is made available under a Creative Commons Attribution Non-Commercial No Derivatives licence. Researchers are free to copy, distribute or transmit the thesis on the condition that they attribute it, that they do not use it for commercial purposes and that they do not alter, transform or build upon it. For any reuse or redistribution, researchers must make clear to others the licence terms of this work. 4 Acknowledgements I own my academic life to the people of my country, who made this possible through their taxes. Gracias Colombia! Thanks to the love, support and pride of my family. Angela, Dominic, Lorenza, Mery, Marta, Uriel, Jose, Beni, Gina, Karin, Galeano, Juancho, Jordy, Gloria, Dani, Hanya, Lulu, Diana. I dedicate this thesis to them. I love your perplexed expressions every time I tried to explain what I do, and you said: “No se preocupe mijo, seguro es importante” I am grateful for the expertise and guidance of my supervisor. Cristina, thank you for your thoughtful feedback, patience, kindness, and for believing in my ability to conduct research. I will miss the confusing, enlightening, and sometimes fruitful meetings we had over the years. I cannot forget to mention Dr James Rosindell, Dr Martin Bidartondo, Prof. Colin Prentice and Provost Clare Ozanne for providing valuable feedback and suggestions that improved this thesis. I am in eternal debt to my Brazilian family, who adopted me during my days in Sao Luiz do Paraitinga, Adelaide (mae), Cavalo, Thaisa, Jacare, Odinho, Paulinho, Lu, Victoria, and all “carne seca” family. Thanks, in particular to Ataliba and Eliana for making field life that much more enjoyable. Also, all the team in Serra do Mar national Park, Sao Paulo, Brazil, for sharing their ticks, feijao and hot water with me. To my friends at Silwood Park Shorok, Jack, Marco and specially to Sophie for her constant support, love and sense of humour that made my stay unique and my time as warden unforgettable. 5 Abstract The high pressure that anthropogenic activities places on tropical forests are pushing species and communities to the brink of local, regional or global extinctions. However, the consequences of the loss of species and their ecosystem functions are not well known. My thesis addresses the causes and consequences of human disturbance on vascular epiphytes in the Brazilian Atlantic forest (BAF). I sampled understory and canopy, across a gradient of habitat loss, i.e. pastureland, human-modified forests (HMFs) and old-growth forest. I found that habitat loss has driven a net loss of 91% of species exclusive to old-growth, and 90% of individuals. I also found the edge effect to be a ubiquitous landscape process extending at least 500 m within forests habitats, leaving just 19.4% of the whole of the BAF suitable for forest-dependant epiphytes. However, whilst endemic species (habitat specialised species) are more prone to disappear as consequence of habitat loss, species with larger dispersal ranges and the ability to colonize different forest types flourish or endure the harsh conditions after disturbance. Consequently, HMFs have low functional richness and low functional redundancy, meaning low resilience, whereas old-growth forests exhibit high ecological resilience. Habitat transformation also leads to the loss of a large set of ecosystem functions related to pollination and water cycling across strata. Hence preserving large continuous forests are probably the only pragmatic conservation strategy for vascular epiphytes in highly human-modified landscapes. However, human-modified forests still provide limited ecosystem functions that may increase because of initiatives to improve habitat amount. 6 Table of content Declaration ................................................................................................................................. 3 Copyright Declaration ................................................................................................................ 4 Abstract ...................................................................................................................................... 6 Table of content ......................................................................................................................... 7 List of figures ........................................................................................................................... 11 List of tables ............................................................................................................................. 13 1 General Introduction ......................................................................................................... 14 1.1 Old-growth forests and human-modified forests ...................................................... 15 1.2 The ubiquitous impacts of edge effects ..................................................................... 16 1.3 Habitat amount and core area .................................................................................... 18 1.4 Functional diversity ................................................................................................... 20 1.5 Vascular epiphytes as a model group ........................................................................ 21 1.6 Disturbance on epiphytes: Winners and losers in habitat disturbance ...................... 22 1.7 Functional strategies to cope with disturbance ......................................................... 24 1.8 Thesis overview......................................................................................................... 26 2 The value of human-modified forests for the conservation of epiphyte communities ..... 29 2.1 Abstract ..................................................................................................................... 29 2.2 Introduction ............................................................................................................... 30 2.3 Material and methods ................................................................................................ 32 7 2.3.1 Study Area ......................................................................................................... 32 2.3.2 Sampled sites and environmental variables ....................................................... 33 2.3.3 Epiphyte sampling ............................................................................................. 34 2.3.4 Statistical analysis .............................................................................................. 36 2.3.5 Statistical analyses ............................................................................................. 38 2.3.6 Ethic statement ................................................................................................... 38 2.4 Results ....................................................................................................................... 38 2.5 Discussion ................................................................................................................. 43 2.6 Supplementary material............................................................................................. 46 3 The influence of edge effects on vascular epiphytes communities .................................. 53 3.1 Abstract ....................................................................................................................