Coastal and Marine Ecosystems of the Bijagós Archipelago – Omatí Minhô

Brief synthesis The Coastal and Marine Ecosystems of the Bijagós Archipelago – Omatí Minhô include a continuous series of coastal and marine ecosystems, corresponding to the marine and intertidal environments of the best-preserved areas with the highest ecological value of the Bijagós Archipelago in Guinea-Bissau. The Bijagós Archipelago is the only active deltaic archipelago on the African Atlantic coast and one of the few in the world. Shaped by important geological and ecological processes, such as upwelling, the convergence of longshore drift and other marine processes, favouring the mobilisation of sediments and the production and exchange of nutrients in the estuaries and mangroves of the Costa das Rias, these environments are fundamental to the productivity and diversity of marine and intertidal life; with mangroves, mudflats and sandbanks that ensure the maintenance of a rich marine biodiversity and important gatherings of aquatic birds; the presence of globally threatened and emblematic species, such as sea turtles, sharks, rays and manatees; and the crucial role in important migrations, such as the migrations of sea turtles in the Atlantic and the migration of birds in the important East Atlantic Flyway, among other ecological processes. Thus, the property is probably the most important site in Africa and one of the most important in the world in terms of sea turtle nesting, and the second most important foraging area in Africa for the East Atlantic Flyway, which is of global importance for migratory birds. Criterion (ix): The Bijagós Archipelago is the only active deltaic archipelago on the Atlantic coast of Africa. The archipelago is particularly important, on the African continent as well as in the Atlantic Ocean and throughout the world, due in particular to the rugged coastline, the width of the continental shelf, the geological and ecological marine processes and land-sea interactions, and the presence of mangroves, estuaries and foreshore shoals. Its origin can be found in the characteristic layout of the islands and delta-shaped channels. The existence of the delta is determined by a series of processes such as the tide, the sedimentary input from the Geba and Corubal rivers, the production and exchange of nutrients in the estuaries and mangroves of the Costa das Rias, upwelling and the convergence of the north and south littoral drifts, which favour the trapping of sediments. These dynamic processes, coupled with shallow areas and reefs, create conditions for high ecological productivity and an important food chain for the maintenance and conservation of life in the marine and intertidal environments where the availability of crustaceans, molluscs and other food sources favours large gatherings of water birds, sharks and rays, manatees, dolphins, sea turtles, among others, some of which are essential for the major migration routes. The deltaic origin of the archipelago also explains the presence of freshwater species that have had to adapt to the progression of marine influences over the millennia. The most representative example is that of the Hippopotamus, the archipelago being the only place on the continent, and thus in the world, where the species lives in seawater on an almost permanent basis. Criterion (x): The vast sand and mud banks and other foreshore habitats of the property constitute key environments for migratory and/or resident species, in particular wading birds, coastal and marine birds, and sea turtles, among other globally important and threatened species. In these conditions, it constitutes the second most important feeding area in West Africa for the East Atlantic Flyway beyond the resident bird colonies. Total estimates range from around 200,000 to 850,000 birds. This includes nearly 105 species of waterbirds, including 53 resident Afrotropical species (from 18 families) and 50 Palaearctic and intra-African migratory species (from 19 families), out of a total of more than 283 species of birds throughout the archipelago. Furthermore, it is probably the most important site in Africa and one of the most important in the world for nesting sea turtles. Five of the seven existing species of sea turtle frequent the Bijagós Archipelago: the Green Turtle, the Olive Ridley Turtle, the Hawksbill Turtle, the Leatherback Turtle and the Loggerhead Turtle. The nesting of Green Turtles is nevertheless the most remarkable, making the property the third most important area in the world, the second most important in the South Atlantic and the most important in the whole of Africa, in terms of the number of nests. Starting from an annual average of 27,251 Green Turtle nests between 2013 and 2017, the records have repeatedly reached almost 40,000 nests, and up to more than 62,000 in 2020, for the beaches of the islet of Poilão alone. Regional and transatlantic migrations of sea turtles have been recorded in association with the property. The property is also a sanctuary for the diversity of sharks and rays, being probably the area with the greatest hopes among the three most important areas in the world for coastal elasmobranchs, and is renowned for the diversity of its fish populations, particularly cartilaginous fish, including the probable last specimens of sawfish on the West African coast. Further threatened species found in the property include African Manatee, dolphins – in particular the Atlantic Humpback Dolphin – and hippopotamuses living in marine habitats. Integrity The boundaries of the property encompass the best-preserved areas of the Bijagós Archipelago, which have the highest ecological value. The results of historical series and the monitoring data at the time of inscription show a high level of integrity of the property and its buffer zone, and do not show a declining trend in the attributes of Outstanding Universal Value. The main factors likely to affect the property and its buffer zone, such as pollution, fishing, navigation, infrastructure development, oil exploration, tourism and climate change, remain at very low and/or distant levels. The components external to the property but which influence its functioning and its dynamic equilibrium are themselves in a remarkable state of integrity. The Geba and Corubal rivers, which supply the archipelago with sediment, have not been subject to major development to date. Their flow rates may be influenced by the climatic situation or by human activities likely to affect their catchment area, particularly in the Fouta Djalon massif in Guinea. However, they do not play a fundamental role in maintaining the functioning of the geo-ecological system of the Bijagós Archipelago. The estuaries and mangroves of the Costa das Rias have not undergone any major transformation, with the exception of moderate pressure on the mangroves for the development of rice cultivation. The absence of industry or major infrastructure on the coastline, the very low intensity of maritime traffic and the low population densities result in a very low level of environmental degradation or minor marine pollution that finds little comparison elsewhere in the world. Although there may be places with some litter in the buffer zone (such as Bubaque), there is minimal evidence of pollution or contamination in the waters and sediments of the property, including possible damage to the birdlife that frequents it. The geomorphological configuration of the archipelago, characterised by vast sand or mud banks and other intertidal habitats associated with shallow areas and reefs, constitute natural barriers to navigation in the Bijagós Archipelago. Artisanal and subsistence fishing remain relatively limited, and industrial fishing efforts are concentrated mainly in areas more than 10 nautical miles from the buffer zone and remain at very low levels (less than 100 hours of fishing effort on 8 km²). No oil exploration and/or exploitation operations are taking place within the property or its buffer zone, and the potential oil drilling areas known today are relatively far from the property. The tourism sector has developed within the archipelago over the past decades, but its development remains limited, however, with an average of only 45,000 visitors per year. In general, there are as yet no signs of significant changes in coastal patterns and the possibilities for transforming environments remain modest in view of technological capabilities. However, there is a strong likelihood that climate change will bring about changes in water circulation patterns, as well as significant changes in sea level and, consequently, potential risks of erosion and sedimentation that differ from the current pattern. Protection and management requirements The exceptional state of conservation of the property is mainly due to the way the area is organised and the traditional management of resources by local communities and the efforts of various government departments and agencies of Guinea-Bissau since the 1980s and 1990s, which have made it possible to establish an adequate protection framework from a legal and/or customary point of view, notably the creation and sound management of the three marine protected areas of the Bijagós Archipelago – João Vieira and Poilão Marine National Park, Orango Islands National Park and the Formosa, Nago and Chediã Islands (Urok Islands) Community Marine Protected Area in 2000 and 2005. In addition, a development and integrated management plan for the Bolama-Bijagós Archipelago Biosphere Reserve, which encompasses the entire property and its buffer zone was adopted in 2023 and provides an overarching layer on top of the individual management plans for the protected areas. At the international level, the Bijagós Archipelago is also recognised as a Biosphere Reserve and as a Wetland of International Importance (Ramsar site). The overall coordination of the management of the property is ensured by the Institute for Biodiversity and Protected Areas, Dr Alfredo Simão da Silva (IBAP). Since its creation in 2005, the work of the IBAP has been continuous and remarkable in the archipelago. It follows, deepens and improves the previous work of the Coastal Planning Office (Gabinete de Planificação Costeira - GPC), the National Institute of Studies and Research (Instituto Nacional de Estudos e Pesquisas - INEP) and the Centre for Applied Fisheries Research (Centro de Investigação da Pesca Aplicada - CIPA), among other government bodies and secretariats. International technical and financial support has been systematic and significant throughout the process. IBAP has recently strengthened its guidelines for the archipelago, orienting the declaration of ecological corridors and the consideration of mangrove areas, shallows, sand and mud banks and other foreshore areas as fundamental elements of the Biosphere Reserve. The inscription of the property shall therefore further strengthen its capacity to continue and improve the successful conservation work. In the future, it may be possible to extend the officially conserved area. In accordance with the proposal for official national recognition of the Bolama-Bijagós Archipelago Biosphere Reserve and its recent management plan, it is planned to carry out further studies and research and social dialogue in order to propose more than one protected area, around the Unhocomo and Unhocomozinho island complex, to propose the formation of areas reserved for fishing, particularly around the islands of Carache and Caravela and Enu, as well as areas for the reinforcement of land conservation on the islands of Caravela and Canhabaque, and the recovery of significant parts of Boloma island.