Islands are often important 'arks' for conservation of terrestrial species
Islands are often vitally important for the conservation of land-based species that are threatened or have gone extinct in other parts of their range. They also often have their own endemic species which have evolved in isolation and are unique to an island or archipelago. In general, the larger the island and the more isolated it is, the more endemism there is. Such ‘island arks’ can also act as important source areas for threatened species, enabling translocation or re-introduction of species back into their former parts of their natural ranges from where they may have disappeared.
Aders' and suni antelope on Mnemba Island
In the early 2000’s, &Beyond, in partnership with local government agencies and the Wildlife Conservation Society, initiated the first in a series of translocations of Aders’ and suni duikers to Mnemba Island in order to establish viable breeding populations safe from the threats the species face in mainland areas.
Aders’ duiker is the rarest antelope in Africa, with estimates of between 300-600 remaining in the wild. In 2005, five were introduced to Mnemba which was regarded as an ideal location given it has no natural predators and a good supply of food. Notoriously secretive, Mnemba is one of very few places in the world where these little animals can be spotted in the wild. Over the years, targeted studies have collected information on the duikers’ diet and behaviour, and the species has increased in number to over 30.
The tiny suni antelope were originally brought to Mnemba from Jozani Forest on Zanzibar. So successful has the breeding program been for these rare little animals, that they have been breeding twice, rather than once every year. With numbers increasing so rapidly, periodical relocations of the species have ensured that there is enough space and food for both the suni and Aders’ duiker. Over the years, more than 250 suni have been successfully moved to 13 sites throughout Zanzibar.
Both the Ader and suni antelope, along with the island vegetation that they are dependent on, continue to be carefully monitored on Mnemba Island to ensure gene pools remain strong, that the carrying capacity of the island is not exceeded, and that there are no adverse impacts of the antelope’s own breeding success on the island’s vegetation and ecological balance.
Vegetation diversity & habitat restoration
Given their isolation from mainland areas, and the protection afforded by conservation concessions, the vegetation communities on both Mnemba and Vamizi Islands are among the best remaining examples of intact coastal vegetation and forest remaining in their respective regions.
Vamizi Island is known to support some of the best preserved coral strand forest communities in East Africa, while Benguerra Island has regionally important sand dune vegetation communities. Although smaller, Mnemba too retains a distinctive vegetation community that has been largely lost on adjacent Zanzibar islands.
Forthcoming projects will facilitate comprehensive vegetation diversity assessments on Mnemba and Vamizi islands. In Vamizi’s case this will also include developing an indigenous plant nursery co-managed by the local community to promote revegetation on degraded or eroded parts of the islands. Mnemba Island already has an established nursery where plants are grown and used to revegetate and stablise areas lost due to beach erosion.
Vamizi Island is home to a sub-species of samanga (or Syke’s) monkey. This unique population exhibits some peculiar and interesting characteristics. The island’s isolation means that the monkey’s gene pool is relatively small which in part explains a high rate of albinism in the population with several pure white individuals observed on the island.
A recent study of the species’ behaviour by researchers from Madrid University found that the monkeys have highly variable foraging behaviours depending on the season. Among some of the more interesting observations is their habit of foraging on exposed reef flats. During low spring tides, when up to 200 metres of beach and reef is exposed, the monkeys can be seen actively searching and hunting for marine animals such as crabs and molluscs, and searching for seaweed, and drift seeds and nuts washed in with the tide.
Terrestrial fauna surveys
Vamizi and Benguerra Islands in Mozambique both have a variety of terrestrial vegetation habitat types that host numerous birds, reptiles, and mammals. Mnemba Island, although small, retains native forest vegetation that has been lost on adjacent areas on Zanzibar, and is an important roosting and nesting place for several species of terrestrial birds.
All of these islands, given their relative isolation from the mainland and limited threats, are important sites for local populations of many terrestrial species. Systematic, inter-seasonal bird surveys have recently commenced on Vamizi and Mnemba Islands in order to comprehensively assess bird diversity and numbers, and how they vary over seasonal and climatic cycles. Dedicated mammal and reptile surveys are also planned in the near future involving scientists and students from local universities.
Learn more about our other projects…
See what we're doing in all our different fields
Using the latest tracking technology we study the movements, habitat use and behaviours of apex predators, including sharks and giant trevally, to inform conservation and the establishment & management of marine protected areas.
Working in close partnership with coastal communities to build capacity, develop sustainable livelihoods, promote marine conservation education and train & employ Marine Community & Conservation Rangers.
Coral Reef Diversity
With some of our sites hosting among the highest coral diversity outside the Coral Triangle, coral reef studies are a major focus of our work including documenting & monitoring coral, fish & invertebrate health, diversity & abundance.
Fisheries & Food Security
Many millions of people depend directly on marine resources in East Africa. Our work contributes to fisheries monitoring, promoting sustainable fishing practices & assessing the nutritional value of fish to people as reef ecosystems change.
Listening in on ocean soundscapes using underwater microphones enables us to monitor the health of coral reef ecosystems, study the behaviour of iconic marine animals and assess the impacts of noise pollution.
Five species of sea turtles occur in the Western Indian Ocean, with our sites supporting important nesting areas for four of these. Our sea turtle nest monitoring projects on Mnemba and Vamizi Islands are amongst the longest continuously running programs in East Africa.
Seascape Mapping & Monitoring
Mapping habitats & multiple use zones & deploying environmental sensors at our sites provides vital information for marine scientists, & informs marine spatial planning and the establishment & management of marine protected areas.
Whales and Dolphins
Numerous whale & dolphin species occur at out sites in East Africa with our focus on regular surveys and monitoring & research of resident and migrating populations, including Humpback Whales, using passive acoustic monitoring (underwater microphones).