Resilience of coastal systems and their human partners : ecological and social profile of coastal systems in Kenya, Mozambique and Tanzania

Abstract

This report explains the ecology and social profile of coastal systems in Kenya, Mozambique and Tanzania in order to contribute to the development of effective strategies to enhance the resilience of marine and coastal systems in the Western Indian Ocean. Special consideration is given to the effects and consequences of climate change and economic development. Eastern Africa’s coastal habitats host rich marine biodiversity with more than 6,000 documented species. Six major rivers flow into the Western Indian Ocean (WIO): the Tana and Athi-Sabaki Rivers in Kenya, the Rufiji and Ruvuma Rivers in Tanzania, and the Zambezi and Limpopo Rivers in Mozambique. Their deltas are ideal nursery grounds and breeding areas for prawns, crabs, sea cucumber, snapper, emperor, grouper and several offshore commercially important tuna and mackerel. However, dams built upstream have reduced water flow and sediment and nutrient discharge to the coast. The resulting decline in productivity has had an adverse effect on fisheries. The WIO, a subset of the Indo-West Pacific Region, has about 5% of the world’s mangrove cover with 10 species. Mangrove forests are valued as carbon sinks that counter the effects of climate change through their high productivity and by trapping carbon in biomass and sediment. They thrive in river mouths where they trap sediments that would otherwise be washed out to sea. They host fishes, crabs, molluscs and flora. Mangrove forests in eastern Africa are in a relatively good state of health. They experienced an attrition rate of about 8% between 1980 and 2005 compared with a global loss of more than 30% over the last 50 years. Nevertheless, economic opportunity tends to overshadow biodiversity and conservation in their management. The great majority are subject to forestry regulations so that they can be utilized as a natural resource. Mangrove harvesting provides benefits to local communities, but when harvesting is excessive, it stunts trees and leads to sparse distribution. Mozambique has 60% of mainland eastern Africa’s mangroves. In Cabo Delgado Province, the forests are increasing in size because there is very little logging. Mangrove forests function as service providers to coral reefs, fisheries, prawn farms and land protection, but this carries little weight in the face of alternative incentives. Tourism development, port construction, agriculture and the insatiable demand for fuel wood are causing indiscriminate cutting of primary mangrove forest. There is little or no replanting in the aftermath. Oil and gas extraction is a potential threat to mangroves. Drilling started in 2013 offshore from Cabo Delgado Province in Mozambique in what is one of the largest natural gas reserves in the world. Safeguarding ethical extraction practices will be critical, hence the development of initiatives such as the Fair Coasts Programme1 , aimed at facilitating direct dialogue between local communities, the government of Mozambique and the drilling companies. Recently considered port construction is a certain threat to the region’s mangroves forests. Local community groups, environment managers and conservationists have voiced concern over expansion plans for the ports at Mtwara and Tanga to accommodate the shipping traffic generated by oil and gas companies. The mangrove forests around Manda and Pate Islands will be removed or damaged when work begins on the Lamu Port Southern Sudan–Ethiopia Transport Corridor (LAPSSET). Mariculture, which is expanding in response to a growing market demand, poses yet another threat. Prawn farmers must not repeat the mistakes made in Asia where a landscape denuded of mangroves exacerbated the catastrophic destruction caused by the 2004 tsunami. Mozambique’s northern reefs in the Quirimbas Archipelago of Cabo Delgado Province are some of the healthiest, most resilient and diverse coral reef systems in the WIO and have been recommended as a World Heritage site. Tanzania’s southern reefs in Mnazi Bay, Mafia Island and the Songo Songo Archipelago are also highly diverse and resilient to climate change. Warmer sea-surface temperatures caused by global warming bleach corals and eventually kill them. The reefs in northern Mozambique and southern Tanzania have demonstrated resilience to bleaching and an ability to return to a coraldominated state after the extreme temperatures of the 1998 El Niño event. The presence of crustose coralline algae on the reefs around Mafia Island and the Songo Songo Islands, a prescursor to coral growth, suggests that if conditions are ideal, their recovery from a bleaching event will take 10–15 years. Coral cover is higher in the Songo Songo Islands than in Mafia Island, probably because the reefs were protected by the turbid water of the Rufiji Delta, which resulted in lower mortality. Kenya’s reefs have suffered mortality levels of more than 80%. Mozambique has a biodiverse coral-reef system with nearly 15% of the WIO’s coral reefs, up to 400 coral species and 295 fish species, primarily in Cabo Delgado and Nampula Provinces. Tanzania has the largest area of coral reefs with 3,500 km2 covered by fringing reefs. However, dynamite fishing is a widespread and uncontrolled practice that has destroyed the reefs to such an extent that many are now dominated by macroalgae. Kenya’s coral reefs, while the fewest, are protected by a network of established marine 1 The Fair Coasts Programme was developed with the support of the Mechanism for Strengthening Capacity of the Civil Society (MASC), the Mitsubishi Foundation for Europe, Middle East and Africa (MCFMEA), the We Effect and Irish Aid. The programme was developed by IUCN ESARO in collaboration with a consortium of national and regional partners. parks and marine reserves that encompass neighbouring seagrass beds and mangrove forests. The marine parks have allowed fish populations to recover over the past 20 years, and the marine reserves are relatively well managed. The Lamu Archipelago hosts rare, endemic species with limited ranges. To maintain a healthy and vibrant coral reef ecosystem in eastern Africa, its countries must commit themselves to creating a large-scale network that can oversee marine protected areas and manage fisheries regionally in an ecosystem-based approach. This is particularly relevant for the northern reefs, which will be more vulnerable to bleaching events than the southern reefs. Mozambique, Tanzania and Kenya have the WIO’s greatest diversity of seagrasses with 12 widely distributed species. These unusually productive ecosystems are found next to shallow fringing coral reefs and serve as nursery grounds and foraging areas for Dugong dugon, turtles and more than 100 species of fish. Seagrass beds are poorly understood, neglected ecosystems that have yet to be recognized for their efficiency in maintaining biodiversity and safeguarding threatened species. Like the mangroves, they combat climate change by storing up to 500 tonnes per hectare of carbon, equivalent to the carbon stored in primary tropical forests. They also stabilize sediment, protect shorelines, purify water and recycle nutrients. Further research is called for to understand better their resilience to climate change and their economic contribution to coastal communities. Seagrass beds continue to be damaged by trawling, seine netting and dynamite fishing. Upstream agriculture also damages seagrass beds, notably the Athi-Sabaki and Tana Deltas in Kenya and the Rufiji Delta in Tanzania. When coastal development is not well managed, it destroys seagrass beds through the unregulated dumping of solid waste, sewage and dredge soil. The proposed Lamu Port, for example, could significantly affect large tracts of seagrass beds that are important turtle and dugong feeding grounds. Marine spatial planning which incorporates segrass beds into national marine conservation policy is needed in the three Resilient Coasts target countries. Many fauna species across the three countries are under stress from human predation, ranging from uncontrolled offshore commercial fishing with foreign longliners and purseiners that accidentally net sharks and rays to targeted fishing for shark fins and meat. Sharks, turtles, dugongs and coelacanths are in particular danger. The population status of almost 50% of all sharks is unknown due to insufficient data. Of those species that have been assessed by the IUCN Specialist Shark Group, 22 are Critically Endangered, 41 are Endangered, 116 are Vulnerable and 133 are Near Threatened. Not a single reef shark was recorded during recent surveys of coral reefs at 74 sites in Mozambique and Tanzania. x The state of turtle populations is a good indicator of the overall health of coastal and marine ecosystems. Five out of seven species of the world’s marine turtles occur in Mozambique, Tanzania and Kenya. All five species are on the IUCN Red List either as Critically Endangered (hawksbill, leatherback) or Endangered (green, olive ridley and loggerhead). Extensive turtle research in the WIO dating back to the 1990s has been central to marine planning exercises for mainland East Africa. However, more specific data are needed on turtle feeding and breeding, and juvenile and adult migratory routes. Very little is known about the dugong population, but it is believed to be declining to the point of extirpation in the WIO. Marine and coastal ecosystems and coastal communities live in critical interdependence with the vulnerability and resilience of one directly affecting the other. However, this interdependence is not properly recognized in legislative frameworks, institutions and social systems. Coastal poverty, as opposed to rural poverty, has distinguishing features. Many coastal resources are less dependent on short-term weather patterns than on terrestrial resources, allowing more reliability, although the ‘fugitive’ nature of other marine resources, particularly fish, adds a level of uncertainty to coastal livelihoods. The open-access nature of many coastal resources, while providing opportunities for people without property or capital, also exposes resources to competition from other users, and to expropriation for other uses, including tourism or conservation. Small-scale fisheries supply up to 98% of the marine catch and are the principal income-generating activity for a large number of households. The diminishing access to resources among the poor, as demand for these resources increases, encourages artisanal fishers to resort to using illegal gear or fishing in protected areas. The fishing industry’s profitability would improve if there were more processing facilities to create added value (in particular in Mozambique and Tanzania), and feeder roads to provide access to markets. Coastal forests and mangroves are important sources of wood, firewood and non-wood products for local communities. More and more coastal forests and wetlands are being cleared not only for subsistence farming but also for irrigated cash-crop plantations sited near rivers. Mangroves are being exploited for timber, firewood and charcoal. Today’s world is increasingly complex and unpredictable. With rapidly changing demographics, economies and climates in a globalized world—we can no longer afford to engage as ‘business as usual’. Effective responses are required at multiple scales and by multiple actors. This report describes the richness and the complexity of coastal systems and their human partners across Mozambique, Tanzania and Kenya. In doing so, it is our hope that it will stimulate new ways of thinking and working together— breaking down the existing sectoral and organizational silos that do not encourage exchange and cooperation, and giving rise to new approaches that better enable alliances, collaborative learning and adaptive management.