Mangrove Forest Ecosystem Services: Biodiversity Drivers, Rehabilitation and Resilience to Climate Change
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Mangrove forest ecosystem services: Biodiversity drivers, rehabilitation and resilience to climate change Clare Duncan A dissertation submitted for the degree of Doctor of Philosophy UCL UCL Department of Geography University College London April 22nd, 2017 DECLARATION I, Clare Anne Duncan, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated appropriately in the thesis. Variations on Chapters 2 and 7 of this thesis have been published in peer-reviewed journals during the course of this PhD study. Citations for these respective publications are: 1. Duncan, C., Thompson, J.R., Pettorelli, N. (2015). The quest for a mechanistic understanding of biodiversity-ecosystem services relationships. Proceedings of the Royal Society B – Biological Sciences, 282, 20151348. 2. Duncan, C., Primavera, J.H., Pettorelli, N., Thompson, J.R., Loma, R.J.A., Koldewey, H.J. (2016). Rehabilitating mangrove ecosystem services: A case study on the relative benefits of abandoned pond reversion from Panay Island, Philippines. Marine Pollution Bulletin, 109, 772-782. J.R. Thompson and N. Pettorelli contributed to the writing and structure of publication 1. R.J.A. Loma assisted in Dumangas Municipality abandoned fishpond identification and mapping from Google Earth imagery conducted in, and J.H. Primavera, N. Pettorelli, J.R. Thompson and H.J. Koldewey contributed to the writing and structure of, publication 2. Both publications are adapted versions of Chapters 2 and 7 of this thesis. Clare Duncan, 22nd April 2017 ABSTRACT Mangrove forests provide a significant contribution to human well-being; particularly through climate change mitigation and adaptation (CCMA) due to disproportionately high carbon sequestration and coastal protection from tropical storms. However, mangrove community structure drivers of these ecosystem services (ES), rehabilitation potential for high CCMA ES delivery, and their resilience to climate change impacts remain poorly understood and monitored. This thesis uses field- and satellite remote sensing-based methods and a dual focus at a Philippines-specific and West Africa to South Asian-scale to quantitatively assess mangrove CCMA ES delivery. The first three chapters provide a background, and literature review on ES delivery, ecological restoration and resilience to perturbations, mangrove ES, their anthropogenic and climate change threats, and current management. Chapters 4 and 5 detail the case study selection and methodologies employed. Chapter 6 focuses on the flora community structure drivers of mangrove ES delivery, and shows that divergent controls can drive trade-offs in the delivery of key CCMA benefits. Chapter 7 focuses on the potential of mangrove rehabilitation for high CCMA ES delivery, and shows that mangrove rehabilitation in abandoned aquaculture ponds can provide high relative CCMA benefits, revealing large areas of abandoned aquaculture with favourable tenure status for greenbelt rehabilitation. Chapter 8 focuses on remote monitoring of mangrove resilience to sea level rise, and the potential anthropogenic and abiotic factors influencing these, establishing a methodology for continued remote monitoring and revealing variability in resilience and resistance across forests. Overall, it is demonstrated that current mangrove management in the Philippines and globally may be insufficient to secure high CCMA ES delivery, due to (1) non- consideration of flora community structure, site-specific and areal requirements, (2) complexity in governance systems for reclamation of mangrove lands, and (3) a lack of spatial planning and zoning to accommodate mangrove resilience to climate- induced perturbations. ACKNOWLEDGEMENTS I would first like to thank my PhD supervisors for their excellent support, advice and expertise, and for enabling me to undertake this PhD in the first place. Nathalie Pettorelli for her tireless advice and mentoring, for all the laughter, and for putting up with me in the office every day! Julian Thompson for putting his faith in me and this project after a phone call out of the blue in 2013, and for providing brilliant guidance and support ever since. Heather Koldewey for sharing her extensive expertise in marine ecology and mangrove conservation, for always being on hand to help (often at very short notice!), and for the occasional bit of San Miguel and karaoke along the way. And Jurgenne Primavera, whose second-to-none passion for mangroves and their conservation continues to inspire me, for sharing her encyclopedic knowledge and experience, and for unwavering support from the other side of the world. I am immensely grateful for the assistance I have received from the ZSL Marine and Freshwater Conservation Programmes teams, both in the Philippines and the UK. Special thanks go to Venus Sadio Calanda, my dear friend, literally without whom the research in Chapters 6 and 7 of this thesis would not have been possible, for all the fun, music (“Avicennia marina, marina, marina!”) and gruelling work in the mangroves. And to Pong Pong and Alex for missing her so enormously for very long periods in the field. This project would also not have been possible without the amazing advice and support of Jo Savaris and Glenn Labrado, nor the constant assistance and laughs from the ZSL-Philippines field and admin teams: huge thanks to Apol Loma, Jofel Coching, Christian Montilijao, Myrtle Arias, Dax Dequito, Pelsy Barber, Rodney Golbeque, Rosalie Villareal Joven, Precil Crispo, Smith Bajon, Lindy Señadoza, Scarlette Coopera, Jude Bagio, Mary Grace Opeña, Ana Mae Mendoza, Marjorie Cañada, Glen Galvez, Emily Sevilla and Gene Fernandez. I would also like to thank Surshti Patel, Louise Baldwin, Becca Short and Dave Curnick for their varied help (and pints) over the last three years. And, of course, to “Barangay Tibay” for the friendship, second Iloilo home during typhoon Hagupit, and always far too many Pilsens – Dax, Rizza, Cindy and Bridget. I am extremely grateful to Mayor Jaen of Leganes, Mayor Distura of Dumangas, Mayor Alvarez of Ajuy, Mayor Bermejo of Panay, Mayor Yap of Ivisan, Mayor Miraflores and Vice-Mayor Solidum of Ibajay, and Mayor Lachica and former-Mayor and -Congressman Quimpo of Kalibo municipalities, as well as all LGU staff (in particular, Sir Wilson Batislaon of Leganes), for access to their wonderful mangrove areas, and for support and assistance provided to this project. In addition, I would like to extend enormous thanks to all of the communities and people’s organisations in Barangays Nabitasan, Ermita, Nanding Lopez, Pedada, Buntod, Balaring, Buswang and Bugtong-Bato for field assistance and logistical support, and for being incredible mangrove stewards. Special thanks go to Ildefonso Denila, Capitan Melquiades Ordena Jr., Elmer Barbiera, Freddie Barbiera, Capitan Felipo Base, Rodolfo Albay and family, Rex Balatayo and family, Capitan Jer Argoncillo, Capitan Teodorico Inguilo, Michelle Fernandez and Elizabeth Ramos. Huge thanks also go to Joey Ardales and Hansel Sacapaño and their familes, for giving up so much of their time to help me in the field, and for all the hilarity and ridiculous situations we got ourselves into. I would also like to thank those who have given methodological assistance along the way. In particular, Esther Caligacion of the Bureau of Soils and Water Management, Cebu, who sacrificed a great deal of time to processing a lot more sediment samples than were originally anticipated. In addition, massive thanks to Lola Fatoyinbo for data access, Will Cornforth for sharing his radar remote sensing expertise, Martin Wegmann, Harry Owen, Jean-Francois Rysman and Judy Reise for analytical advice and support, Xav Harrison for statistical assistance (and, again, pints), Ellie Dyer and Dave Redding for INLA advice (and in Ellie’s case, for fielding frantic texts about thesis formatting in the middle of the night!), and Ben Thompson, Rebecca O’Brien, Dan Friess, Joanna Ellison and Stefano Cannicci, and my examiners Mark Huxham and Emily Lines, for discussion and advice. This project would also not have been possible without the generous support of funders: the Rufford Foundation and the Darwin Initiative. I would like to thank my friends and colleagues at the IoZ for making this process all the more bearable on a day-to-day basis; in particular, Kirsten McMillan, Lola Brooks, Monni Böhm, Jon Bielby and Sam Turvey for friendship, support, mentoring, and putting up with more than their fair share of moaning. Lastly, my biggest thanks go to my friends and family for the relentless support and encouragement they have given me over the last three years, and for witnessing me in my most stressed-out moments. And, because she insists I must mention her by name here, to my best friend, flatmate and life partner, Izzy Thompson, for being truly horrid throughout. TABLE OF CONTENTS LIST OF TABLES ................................................................................................................................................................. 1 LIST OF FIGURES ............................................................................................................................................................... 3 LIST OF ACRONYMS .......................................................................................................................................................... 6 CHAPTER 1: INTRODUCTION, STUDY AIMS AND OBJECTIVES .........................................................................