Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2008 Avian diversification in the afrotropics Ben D. Marks Louisiana State University and Agricultural and Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Recommended Citation Marks, Ben D., "Avian diversification in the afrotropics" (2008). LSU Doctoral Dissertations. 3021. https://digitalcommons.lsu.edu/gradschool_dissertations/3021 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. AVIAN DIVERSIFICATION IN THE AFROTROPICS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Biological Sciences by Ben D. Marks B. A., The Evergreen State College, 1995 M.S., Illinois State University, 2000 May 2008 ACKNOWLEDGMENTS I owe a great debt of gratitude to my advisor Frederick H. Sheldon for his patient support, lunchtime discussions, and careful editing of manuscripts during my years in graduate school. Time spent together in the forests of Borneo and on fishing trips will be some of my fondest memories of graduate school. I would also like to thank the other members of my graduate committee, J. V. Remsen, Michael E. Hellberg, and Robb T. Brumfield, for their time and efforts. This work would not have been possible without the efforts of many dedicated collectors, museum curators, and collection managers over several decades. Museums that contributed specimens to this project include (in descending order according to the number of specimens): Field Museum of Natural History; Zoological Museum University of Copenhagen; American Museum of Natural History; Louisiana State University Museum of Natural Science; National Museum of Natural History; and the Academy of Natural Sciences, Philadelphia. I would specifically like to acknowledge the help of Drs. Bashwira and Charles Kahindo, Robert Kizungu, and all of my colleagues at CRSN Lwiro, DRC, Mike Adu’ncia at the Ghana Wildlife Authority, John Mason and all of the wonderful people at NCRC in Accra, Ghana, Drs. Robert Kityo, and Christine Dranzoa, and Prof. Derek Pomeroy, Makerere University, and the Uganda Wildlife Authority. For funding, I thank the Chapman Memorial Fund of the American Museum of Natural History, NSF ATOL grant to FHS (DEB-0228688), T. Vinton Holmes, the Biological Sciences Graduate Students Organization (BioGrads), and the LSU Birdathon and all its supporters. Numerous individuals facilitated my efforts over the years of this project. The following people went out of their way to help me at one or more times: Saara DeWalt, Jason Weckstein, Rob Moyle, Chris Witt, Adam Leaché, Jessica Light, Kazuya Naoki, Alex Aleixo, Donna Dittmann, Steve Cardiff, Nannette Crochet, Santiago Claramunt, Mario Cohn-Haft, John Bates, Shannon Hackett, David Willard, Tom Schulenberg, Matt Carling, Zac Cheviron, Rauri Bowie, Tom Devitt, Frank Burbrink, Laurie Benson, Mark, McRae, Jason Walker, Gwen Mahon, Peggy Sims, and Tammie Jackson. ii I have appreciated friendship and moral support of many other people that have been invaluable in helping me learn and have fun as I worked my way through the process of graduate school. These include, but are not limited to: Tom Gnoske, Jose (Pepe) Tello, Amy Driskell, Bill Stanley, Mike Huhndorf, Tom Schulenberg, Michi Solomon, Charles Kahindo, Kalan Ickes, Mike Taylor, Paul Gagnon, Heather Passmore, Carrie Yoder, Mark McRae, Lori Benson, Tom Devitt, Brian O’Shea, Andres Vidal, Richard Dewell, Dan Lane, and Ron Eytan. For anyone who happened upon this section who I have neglected to single out due to sheer exhaustion, I apologize for the slight—rest assured I appreciate your help and friendship. Finally, I would not have been able to make it through the final phase of this exhausting process without the unconditional love and support of my family, my naughty little dogs Chapin and Athena, and the love of my life Jessie. iii TABLE OF CONTENTS ACKNOWLEGEMENTS……...…………………………………………………….....................ii ABSTRACT……………………………………………………………………………………….v CHAPTER 1. INTRODUCTION…………………………..…………………………………………1 2. PHYLOGEOGRAPHY OF THE RED-TAILED BRISTLEBILL (BLEDA SYNDACTYLUS)...……………..........................................................................................8 3. PHYLOGEOGRAPHY OF THE YELLOW-WHISKERED GREENBUL (ANDROPADUS LATIROSTRIS)………..………………………………………………37 4. PHYLOGEOGRAPHY OF THE GREEN HYLIA (HYLIA PRASINA)……………..73 5. CONCLUSIONS ....………………………………………………………………...100 REFERENCES ………………...………………………………………………………………105 APPENDIX: SAMPLING LOCALITIES AND VOUCHER INFORMATION FOR SAMPLES ANALYZED IN CHAPTER 3…………...………………………………………………….....112 VITA……………………………………………………………………………………………117 iv ABSTRACT Widespread bird species endemic to the lowlands of the Guineo-Congolian rainforest of Africa have traditionally been thought to lack substantial intraspecific structure. This view owes largely to their widespread distributions coupled with the absence of discrete geographic variation in plumage. In the following chapters I examine the phylogeographic patterns of three such species using a combination of molecular and morphometric data. The three species investigated are the Green Hylia (Hylia prasina), the Red-tailed Bristlebill (Bleda syndactylus), and the Yellow-whiskered Greenbul (Andropadus latirostris). Using the phylogeographic patterns from these data, I assess 1) models of rainforest species diversification, 2) current taxonomy, and 3) implications for conservation of lowland rainforests. In contrast to the lack of discrete plumage variation in these species, phylogeographic analyses reveal a high degree molecular and morphological divergence. Furthermore, general patterns of geographical structure of the mtDNA data are largely congruent among the three species. Each species has unique mtDNA haplotype groups in Liberia, Ghana, Cameroon- Gabon, Central African Republic, and the eastern Democratic Republic of Congo. Andropadus latirostris, which also occurs in montane forests, has unique haplotype groups in these montane regions. Taken together the patterns of geographic variation in molecular and morphological datasets from these three species suggest a history of allopatric divergence via genetic drift, consistent with predictions of refugial diversification. There is also some evidence for a potential role for divergent selection along a longitudinal temperature gradient in shaping the morphometric diversity in Andropadus latirostris. Despite their widespread distributions and the potential for high gene flow, these three species exhibit a remarkable level of geographic structure across the lowland rainforest. This contradicts the prevailing view of widespread lowland species as large panmictic populations. v This significant geographic structure has important implications for species and habitat conservation in Africa, where lowland forest is typically viewed as a continuous block of homogenous habitat. The implication is habitat loss in one area would not result in a substantial loss of biodiversity because many of the species are widely distributed. The geographic structure evident in these data suggests that that is not the case. vi CHAPTER 1. INTRODUCTION Tropical rainforests harbor the highest species diversity and endemism on the planet. The occurrence of such remarkable diversity led some of the earliest biogeographers to ponder the evolutionary mechanisms responsible for producing it. The model they sought would have general explanatory power and take into account the wide variety of forces that can cause diversification, including vagaries of geological history, natural selection, and drift. However, the model has proved elusive, and 100-year search for it has created a great deal of debate among researchers interested in biodiversity. In my dissertation I focus on the Afrotropics, and specifically the diversity of the Guineo-Congolian lowland rainforest avifauna. My primary goal is to reconcile the debate about the forces of tropical diversification, specifically as it pertains to Africa, by careful examination of genetic and morphological variation in birds of the rainforest. The lowland rainforest of sub-Saharan Africa extends from Sierra Leone in the west through the Democratic Republic of Congo and western Uganda in the east. This broad expanse of forest is currently fragmented into two major blocks by the Dahomey Gap (in Benin), where woodland savanna habitat that lies north of the forest extends all the way south to the Gulf of Guinea. The forest to the west of the Dahomey Gap is known as the Upper Guinea (UG) forest block. To the east is the Lower Guinea (LG) forest block, which can be further subdivided into Western (WLG) and Eastern Lower Guinea (ELG) across the Congo basin (Mayr and O’Hara 1986). These major divisions in the Guineo-Congolian forest correspond areas of endemism and to the putative locations of forest refugia (Figure 1.1). In the Afrotropics, three models have dominated discussions of species diversification. The original model (Chapin 1932, Moreau 1954, Fjeldså 1994) evokes natural selection acting across ecotones (habitat transitions) along the periphery of the