This open access book presents a comprehensive synthesis of the biodiversity of the oceanic islands of the Gulf of Guinea, a biodiversity hotspot off the west coast of Central Africa. Written by experts, the book compiles data from a plethora of sources – archives, museums, bibliography, official reports and previously unpublished data – to provide readers with the most updated information about the biological richness of these islands and the conservation issues they face. The Gulf of Guinea Oceanic Islands (Príncipe, São Tomé and Annobón and surrounding islets) present extraordinary levels of endemism across different animal, fungi and plant groups. This very high endemism likely results from the long geological history of the islands and their proximity to the diversity-rich continent. Many researchers, students and conservationists from across the globe are interested in documenting biodiversity on the islands, understanding the evolutionary origins of this diversity, and mitigating the impacts of global change on this unique archipelago. This book aims to be a primer for a broad audience seeking baseline biodiversity information and to serve as a roadmap for future research efforts aiming to fill knowledge gaps in understanding and conserving the unparalleled biodiversity of the Gulf of Guinea islands.

The Gulf of Guinea Conservation Group describes and provides photographs of the biodiversity of the four Gulf of Guinea islands of Bioko, Principe, Sao Tome, and Annobon. The group devotes itself to species and ecosystem conservation and environmental protection of the islands.

Oceanic islands represent a set of systems in which biological diversity varies as a consequence of remoteness or size, not environment; they are also generally simpler than continental ecosystems. Islands therefore provide an opportunity to determine the direct effects of biological diversity on ecosystem function. The volume addresses the components of biological diversity on islands and their patterns of variation; the modern threats to the maintenance of biological diversity on islands; the consequences of island biology and its modification by humanity regarding aspects of ecosystem function; the global implications of islands for conservation; and how islands can help one to understand the processes inducing changes throughout the world.

Life began in the sea, and even today most of the deep diversity of the planet is marine. This is often forgotten, especially in tropical countries like Costa Rica, renowned for their rain forests and the multitude of life forms found therein. Thus this book focusing on marine diversity of Costa Rica is particularly welcome. How many marine species are there in Costa Rica? The authors report a total of 6,777 species, or 3. 5% of the world’s total. Yet the vast majority of marine species have yet to be formally described. Recent estimates of the numbers of species on coral reefs range from 1–9 million, so that the true number of marine species in Costa Rica is certainly far higher. In some groups the numbers are likely to be vastly higher because to date they have been so little studied. Only one species of nematode is reported, despite the fact that it has been said that nematodes are the most diverse of all marine groups. In better studied groups such as mollusks and crustaceans, reported numbers are in the thousands, but even in these groups many species remain to be described. Indeed the task of describing marine species is daunting – if there really are about 9 million marine species and Costa Rica has 3. 5% of them, then the total number would be over 300,000. Clearly, so much remains to be done that new approaches are needed. Genetic methods have en- mous promise in this regard.

J. L. Gressitt New Guinea is a fantastic island, unique and fascinating. It is an area of incredible variety of geomorphology, biota, peoples, languages, history, tradi tions and cultures. Diversity is its prime characteristic, whatever the subject of interest. To a biogeographer it is tantalizing, as well as confusing or frustrating when trying to determine the history of its biota. To an ecologist, and to all biologists, it is a happy hunting ground of endless surprises and unanswered questions. To a conservationist it is like a dream come true, a "flash-back" of a few centuries, as well as a challenge for the future. New Guinea is so special that it is hard to compare it with other islands or tropical areas. It is something apart, with its very complicated history (chapters I: 2-4, II: 1-4, III: I, VI: I, 2). It is partly old but to a great extent very young, yet extremely rich and complex. It has biota of different sources - to such a degree that it is still disputed in this volume as to what Realm it belongs to: the Paleotropical or Notogaean (Australian); or what Region: Oriental, "Oceanic," Papuan or Australian. The terms Papuasian, Indo-Australian and Australasian also have been applied to the area.