Durham E-Theses Simulating range shifts of African mammals under predicted climate change: potential conservation and economic consequences Palmer, Georgina How to cite: Palmer, Georgina (2008) Simulating range shifts of African mammals under predicted climate change: potential conservation and economic consequences, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/2319/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 Simulating Range Shifts of African Mammals under Predicted Climate Change: Potential Conservation and Economic Consequences Georgina Palmer B.Sc. (Hons) The copyright of this thesis rests with the author or the university to which it was submitted. No quotation from it, or information derived from it may be published without the prior written consent of the author or university, and any information derived from it should be acknowledged. Institute ofEcosystem Science, School ofBiological and Biomedical Sciences, Durham University 2008 This thesis is submitted in candidature for the degt:ee of Master ofScience 1 8 DEC 2008 Declaration The material contained within this thesis has not previously been submitted for a degree at Durham University or any other University. The research reported within this thesis has been conducted by the author unless indicated otherwise. © The copyright of this thesis rests with the author. No parts of this thesis should be reproduced Without prior consent from the author, and quotations should be acknowledged. 11 Abstract Simulated present-day ranges of 281 African mammal species were produced using climate-envelope models. This modeling approach was robust and was therefore used to simulate potential future ranges of 281 African mammals in response to nine future climate change scenarios (three general circulation models for 2020, 2050 and 2080). The size of species' ranges were projected to decrease only slightly (-4.411%) on average by 2080. Species' future ranges were projected to overlap current ranges by only 75.7% on average by 2080. The effectiveness of the African protected area (PA) network under projected future climate change was then assessed by intersecting simulated ranges with PA outlines at the quarter degree scale. By 2080, the mean decrease in species richness was projected to be 7.18% under a best-case scenario of range shift, which is greater that that projected for areas of Africa beyond PAs (-4.41%). By 2080, mean species persistence and turnover within PAs were projected to be, on average, 79% and 26% respectively. Species turnover will be unevenly spread across the PA network; PAs in South Africa and Namibia wiH be affected most by climate change. Simulations indicated the loss of keystone and charismatic species from a number of PAs, including Kruger National Park (KNP). The value of two keystone species in KNP was assessed using the contingent valuation method. Significant factors influencing willingness-to-pay included respondents' age, employment status and experience of visiting the PA. Aggregated willingness-to-pay values were R87.3million (± R17.4million) per year for ensemble species conservation, R4Llmillion (± Rl7.8million) for giraffe (Giraffa camelopardalis) and R42.4million (± Rl4.3million) for elephant (Loxodonta africana) conservation. Until greenhouse gas emissions are stabilised (or reduced), it is inevitable that further climate change, and therefore further alterations of species distributions will occur. Efforts such as increasing the extent and connectedness of the P A network may help to protect species threatened by projected climate change by allowing them the opportunity of tracking climate change. 111 Acknowledgements This thesis is written and analysed wholly by myself, (unless referenced) however the production of this work could not have happened without the support of a number of people. Special thanks must go especially to Dr Stephen Willis, my primary supervisor, whose support has been invaluable throughout the past year, and also to my eo­ supervisors, Prof Brian Huntley and Prof Nicholas Hanley. Many thanks also to my colleagues in the Institute ofEcosystem Science; Andy, Andy, Jemma, Jon, Judy, Nat, and Rachael as well as Yvonne and Dave for al1l of their technical support- plus endless offers of coffee. Numerous people helped to make the fieldtrip to South Africa run smoothy. Thanks must go to Patricia Khoza, Thembi Khoza, Kevin Moore and Ernita van Wyk for their technical and logistical support in Kruger National Park, and to George Frater who helped to collect data. Thanks must also go to the School of Biological .and Biomedical Sciences and St. Mary's College, Durham University, for fmancial help towards the cost of fieldwork. I would also like to acknowledge Julian Blanc, for the provision of present-day distribution data of African elephants. Many thanks must go to friends in Liverpool and Durham (especially Alex, Sam and Laura) for their support. And finally to my family, especiaHy Mum and Dad for their endless encouragement (and fmancial support!) during my time at Durham. iv Table of Contents Declaration ................ .,. .............................................................................. .ii Abstract .................................................................................................... .ii Acknowledgements ....................................................................................... .iv PART ONE: Modelling Current and Future Distributions of African Mammals CHAPTER ONE: Introduction 1.1. INTRODUCTION .................................................................................. 1 1.1.1 .. Climate Change ................................................................................ 1 1.1.1.1. Past and Current Changes ......................................................... 1 1.1.1.2. Potential Future Changes .......................................................... .3 1.1.2. Species Responses to Climate Change .................................................. 7 1.1.2.1. Changes in Community and Ecosystem Composition ....................... 12 1.1.2.2. Responses of Terrestrial Mammals to Climate Change ...................... 12 1.1.3. Species Distribution Modelling ......................................................... 17 1.1.3 .1. Evaluating the Accumcy of Species-Distribution Models ...................21 1.2. Aims ............................................................................................................... 25 1.3. Thesis Plan................ "'·' ..................................................................... 25 CHAPTER TWO: Simulating the Current Range of African Mammals 2.1.INTRODUCTION ..................................................................................26 2.2.METHOOOLOGY ..................................................................................... 28 2.2.1.. Species Datasets ............................................................................ 28 2.2.2. Climate Datasets .........................................." ........................................ 29 2.2.3. Climate Response Surfaces .............................................................29 2.3 .. RESULTS ...............................................................................................31 2.3.1. Model Validation .............................................................................31 2.3.1.1. The Receiver Opemting Characteristic ~ROC) Curve ......................... 31 2.3.1.2. Using CRS Models to Simulate Species Occurrences in Protected Areas.34 2.3.2. Model Performance .......................................................................36 2.3.3. Effect of Species' Extent of Occurrence on Model Performance ..................40 2.3.4. Effect of Species' Geographic Location on Model Performance ..................41 2.4.DISCUSSION .......................................................................................43 V CHAPTER THREE: Simulating Range Shifts of African Mammals under Predicted Climate Change 3.1 INTRODUCTION: ...............................................................................46 3.1.1 Objectives................................................................................. 49 3.2 METHODOLOGY ................................................................................. 49 3.2.1. Climate Datasets ......................................................................... 49 3.2.2. Assessing the potential future distributions of African mammals .... , ...........51 3.2.2.1. Species Richness ....................................................... ,,, ............51 3.2.2.2. Species Prevalence ........................................... , ........................ 51 3.2.2.3. Species Range Shifts- in Space and Time ...................................... 51 3.3. RESULTS: