Biotic Surveys of Bioko and Rio Muni, Equatorial Guinea Date: 25 June 1999 Submitted to: Biodiversity Support Program Submitted by: Brenda Larison1, Thomas B. Smith1,3 , Derek Girman2, Donald Stauffer1, Borja Milá1, Robert C. Drewes4, Charles E. Griswold5, Jens V. Vindum4, Darrell Ubick5, Kim O'Keefe1, Jose Nguema6, Lindsay Henwood4 1Center for Tropical Research 2Department of Biology San Francisco State University Sonoma State University San Francisco, CA 94132 USA Sonoma, CA 95476 USA (415) 338-1089 Tel (415) 338-0927 Fax [email protected] email 3Center for Population Biology 4Department of Herpetology University of California California Academy of Sciences Davis, CA 95616 USA San Francisco, CA 94118 USA 5Department of Entomology 6C.U.R.E.F. California Academy of Sciences APDO 207 San Francisco, CA 94118 USA Bata, Equatorial Guinea TABLE OF CONTENTS EXECUTIVE SUMMARY 1 INTRODUCTION 5 PART I. BIOTIC SURVEYS OF RIO MUNI Chapter 1. Bird and Mammal surveys of Rio Muni INTRODUCTION 9 METHODS 9 RESULTS BIRD SURVEYS 16 MAMMAL SURVEYS 46 SOCIO- POLITICAL CONTEXT 51 DISCUSSION 53 PART II. BIOTIC SURVEYS OF BIOKO Chapter 2. Preliminary Report on a Survey of The Herpetofauna of Bioko, Equatorial Guinea INTRODUCTION 58 METHODS 58 RESULTS 58 TENTATIVE CONCLUSIONS 60 Chapter 3. Arthropod surveys on Bioko, Equatorial Guinea INTRODUCTION 62 METHODS 62 RESULTS FLIES (DIPTERA) 63 CARABID BEETLES(C ARABIDAE) 64 SPIDERS (ARANEAE) 65 DISCUSSION OF TARGET TAXA 112 CONSERVATION IMPORTANCE OF BIOKO 114 PART III. B IOGEOGRAPHY ii Chapter 4. Comparative avian phylogeography of Cameroon andEquatorial Guinea mountains: implications for conservation INTRODUCTION 115 METHODS 116 RESULTS PHYLOGEOGRAPHIC PATTERNS 120 PHYLOGENETIC DIVERSITY ANALYSIS 121 GEOGRAPHIC PATTERNS OF ENDEMISM 123 DISCUSSION 125 PART IV. A NNOTATED BIBLIOGRAPHY GENERAL 129 FLORA ALGAE 129 PLANTS 129 FAUNA PROTISTS 135 INVERTEBRATES 135 Gastropods Arthropods VERTEBRATES 138 Fish Herpetofauna Birds Mammals CONSERVATION ISSUES 151 PART V. C ONSERVATION RECOMMENDATIONS 155 iii EXECUTIVE SUMMARY Biotic surveys and a comprehensive literature review were undertaken to improve our knowledge of the biodiversity of Bioko and mainland Equatorial Guinea. Bird and mammal surveys were conducted on the mainland, and herpetological and arthropod surveys on Bioko, providing new information on species distributions and abundance. On the mainland, five areas within the proposed preserve system for Equatorial Guinea; Reserva Natural de Rio Campo, Parque Nacional de Los Altos de Nsork, Parque Nacional de Monte Alen (including Montes Mitra), and Reserva Natural del Estuario del Muni, were examined. On Bioko, the two proposed reserve areas, Parque Nacional de Pico Basilé Reserva Científica de la Caldera de Luba, as well as some lowland areas near Luba were examined. Additionally, genetic data were gathered for birds, and combined with previous data from Cameroon, to assess patterns of genetic differentiation within and across mountains in Cameroon and Bioko. We recorded only one species of bird (Malimbus scutatus) that had not been previously reported for mainland Equatorial Guinea, and no new mammals. However, valuable new information on bird and mammal distributions within Rio Muni are presented. In addition, several species and one genus of amphibians were recorded on Bioko for the first time. Approximately a third of the arthropods, including 372 species of spiders were previously unrecorded, and many are unidentifiable from the literature and may be new species. At least three endemic species of Carabid beetles were also discovered. Conservation implications are discussed in each chapter, and in a separate section (Part V) devoted to conservation recommendations. Conservation actions we recommend include: 1) Maximize protection of regions with high numbers of endemic species (Mountains/Bioko) 2) Preserve elevational gradients whenever possible 3) Create a network of preserves representing different habitat types and climatic zones, as proposed by C.U.R.E.F. 4) Increase conservation education and develop sustainable alternatives to hunting and logging. Thirteen areas have been proposed for conservation by Proyecto Conservacion Utilizacion Racional de los Ecosystemas Forestales des Guinea Equatorial (C.U.R.E.F.). These include two on Bioko, Parque Nacional de Pico Basilé and Reserva Científica de la Caldera de Luba; Nine on the mainland, Parque Nacional de Monte Alen (including Montes Mitra), Reserva Natural del Estuario del Muni, Parque Nacional de Los Altos de Nsork, Reserva Natural de Rio Campo, Reserva Natural de Monte Timeline, Monumento Natural de Piedra Bere, Monumento Natural de Piedra Nzas, Reserva Natural de Punta Llende, Reserva Científica de Playa Nendyi; one comprised of offshore islands, Reserva Natural de Corisco y Elobeyes; and Reserva Natural de Annobon, a small oceanic island. Pico Basilé and Reserva Científica de la Caldera de Luba cover a range of habitats including lowland rainforest, montane and mossy forest, forest, high elevation shrub formation, and subalpine meadows. The island is regionally important because of its genetic uniquenes and high levels of endemism. The island's one endemic bird, Speirops brunneus, is found only on Pico Basilé, and three species of flightless Carabid beetles discovered there are likely to be endemic. The area is threatened by hunting and selective logging. Reserva Científica de la Caldera de Luba would preserve a rainforest gradient from sea level to 2260m, rivaled only by that found on Mt. Cameroon, which is threatened by considerable population pressure. Caldera de Luba is home to seven primate species, four of which are endemic subspecies, and four of which are listed as endangered by IUCN. Primate densities in this area are among the highest recorded anywhere in Africa. 1 However, more recent surveys indicate significant declines in primate populations due to hunting. On the mainland, a number of conservation areas are proposed that would protect a variety of habitats. Parque Nacional de Monte Alen (including Montes Mitra), would, in conjunction with Reserva Natural del Estuario del Muni preserve a potentially important forested elevational gradient for species that undergo seasonal migrations or nomadic movements. The area harbors fifteen species of primates, including several which are vulnerable or endangered. Monte Alen proper is the only area in Equatorial Guinea which has formal protection (there is no hunting or gathering allowed in the park), and is the most well studied area on the mainland. Montes Mitra is a proposed extension of Monte Alen, but logging concessions have been granted within the proposed conservation area, which, together with the bushmeat industry, represent a primary threat to the preservation of an intact elevational gradient. Reserva Natural de Rio Campo will likely be one of the more difficult areas to protect, in that it is bisected by roads, and elephant and buffalo populations have reportedly already suffered from government intervention to protect crops of the local inhabitants. Nonetheless, there are some sound reasons for pursuing some level of conservation here, and the possibility of connecting this area with Cameroon’s Rio Campo Reserve, adds to its conservation value. Parque Nacional de Los Altos de Nsork has only a sparse human population around its perimeter, and has poor access to markets. Nsork is the only area (among Nsork, Rio Campo, and Montes Mitra) where we encountered sign of all three of the large primates, Gorilla, Mandrill and Chimpanzee, and the lack of access to markets may, in part, account for this. Reserva Natural del Estuario del Muni contains the largest, best preserved expanse of mangroves in the country. The area is sparsely populated and has important fisheries. The area is rich in aquatic avifauna and contains prime habitat for the manatee. Reserva Natural de Monte Temelon, Monumento Natural de Piedra Bere, and Monumento Natural de Piedra Nzas are characterized by the presence of inselbergs surrounded by well-preserved forest. These spectacular rocky formations may host endemic arthropods and herpetofauna due to their high degree of isolation, and constitute a potential ecotourist destination. Reserva Natural de Punta Llende is part of the coastal savanna/rainforest mosaic. The savanna areas include birds species found nowhere else in the country and further surveys and research are needed. Reserva Científica de Playa Nendyi includes isolated turtle nesting beaches with associated marine habitat. Additionally, two other offshore areas, Reserva Natural de Corisco y Elobeyes and Annobon are proposed for protection. Reserva Natural de Corisco y Elobeyes includes several offshore islands with important marine bird colonies, and associated marine habitat providing feeding grounds for marine turtles. Reserva Natural de Annobon, an oceanic with its associated marine habitat, is rich in animal and plant endemics, and coral reefs. RESUMEN Se llevaron a cabo relevamientos bióticos y una revisión de la literatura a fin de mejorar el conocimiento de la biodiversidad de Bioko y la parte continental de Guinea Ecuatorial. Los muestreos de mamíferos y aves fueron efectuados en la zona continental, y los de reptiles, anfibios y artrópodos tuvieron lugar en Bioko, aportando nueva información sobre la distribución y abundancia de especies. En la zona continental se visitaron cinco áreas incluidas en el sistema de reservas propuesto recientemente para Guinea Ecuatorial: la Reserva Natural de