Following is a detailed inventory of biodiversity in Zanzibar in order to determine any vulnerable, threatened or endangered species that might be present in the project area.
Zanzibar consists of a mosaic of vegetation ranging from short coral rag bushes and thickets to higher, closed forests. Like many tropical forests, closed forests of Zanzibar have a bottom layer of herbaceous species, a network of climbers and upper layer of perennial species. Key variety of dominant species include Coconut (Cocos nucifera), Areca catechu (Mpopoo), Elaeis guneensis (Mchikichi), Raffia palm or Raphia farinifera (Muwale), Phoenix reclinata (Ukindu), and many more. There are also many species of medicinal significance, some with ornamental value, and others available for a multitude of uses.
In general, dominant exotic species in Zanzibar include pines or conifers such as Pinus patula (Misonobari), various species of Eucalyptus or Mikaratusi (e.g. E. zanzibarica and E. modernii, Casuarina equisetofolia (Mvinje), Acacia ingusetefolia, Terminalia catappa (Mkungu), Terminalia everensis (Mkungu wa Kihindi), Teak or Msaji (Tectona grandis), and Callophyllum inophyllum (Mtondoo). These tree species have been planted in most forests as well as in different places in Zanzibar such as along the roads and surrounding other building complexes.
Jozani Forest Reserve - located about 35 km south of Zanzibar town in the island of Unguja, Jozani is the largest forest reserve in Zanzibar. There are also isolated pockets of natural and established forest stands which are found in the following locations: Masingini – Located a few kilometers north-east of Zanzibar town, which is maintained by the forest sub-commission. Masingini and the adjoining Mwanyanya have both natural and established forests. A nursery located at Mwanyanya is instrumental in afforestation activities in Zanzibar. Kichwele - located in northern part of Unguja island is popular for its rubber plantation (about 600 ha) but the neighboring areas of Pangeni have a good stand of natural forest. Kiwengwa - north-east of Unguja Island has only recently been recognized as an area in need of a well-planned conservation scheme.
Zanzibar's mammal population is very small with only 54 terrestrial species, out of which 23 species are bats. Most of the mammals are found on Unguja Island. Key mammals of conservation concern include:
Red Colobus Monkey (Procolobus kirkii) – IUCN Status – ENDANGERED: This species is endemic to Zanzibar Island where it occurs at elevations of 0-110 m. It is found mainly in the south-eastern part of the island in Jozani-Chwaka Bay National Park, the adjacent agricultural areas to the south, and the coral thickets and mangrove swamps of Uzi Island 10 km to the south-west. Also found at low densities in isolated populations in the coral thickets along Zanzibar’s eastern coast from Kiwengwa in the north to Mnyambiji in the south, and on the west coast there is a small isolated group in the mangrove swamps of Maji Mekundu. A small translocated population of ca. 56 individuals also occurs in Masingini Forest Reserve.
The remaining populations are severely threatened by habitat destruction resulting from timber felling, charcoal production, clearance for cultivation, and bush-burning. This species is occasionally shot for food, sport, or as a supposed crop pest, but habitat loss remains the most serious threat. In Jozani Chwaka Bay National Park, habitat degradation occurred in the past mainly from commercial logging, agriculture, tree-cutting for fuelwood, and charcoal production, but this has now stopped. There are occasional deaths due to road kills south of the park.
Bush Tailed Mongoose (Bdeogale crassicauda) – IUCN Status – LEAST CONCERN: The nocturnal and shy mongoose inhabits the coral rag forest of the south-eastern area of Unguja island but in Pemba it is found in the deep soil areas on the western side of the island. The local name in Pemba is "Chonjwe" and hobby hunters usually encounter this mongoose when hunting for the Small Indian civet.
Zanzibar Tree Hyrax (Dendrohyrax validus) - IUCN Status – NEAR THREATENED: also nocturnal, this tree hyrax is common in Jozani and its habitat comprises trees and caves in coral rag forest. It is believed to be the earliest hyrax species adapted to forest life and possesses the characteristic of having four digits on its front feet and three on its hind feet. The main threats to this species are severe forest loss, degradation, fragmentation (mainly due to logging and burning), and hunting, logging, including selective logging of large trees, removal of shelter trees, destruction of arboreal pathways.
Zanzibar Slender Mongoose (Herpestes sanguineus) – IUCN Status – LEAST CONCERN: This is a common resident of coral rag forest. Present in a wide variety of habitats and occur on forest fringes, and may penetrate into forests along roads and are sometimes found around villages. Slender Mongooses are generally carnivores, their diet primarily comprising of small vertebrates and invertebrates
Zanzibar Suni or Dwarf antelope (Neotragus moschatus) – IUCN Status – LEAST CONCERN: This is also a coral rag animal and commonly found in Jozani forest especially among Psiadia arabica and Todalia spp trees. Usually found near water sources. Lifelong pairs protect a territory of 3 ha in which they raise one fawn per year under favorable conditions.
Zanzibar Leopard (Panthera pardus) – IUCN Status – NEAR THREATENED. LIKELY EXTINCT in ZANZIBAR. Its existence is debatable but believed to inhabit some areas of Unguja Island. The population size is totally not known, however, it is associated with witchcraft and is believed to be employed by evil-doers who keep the animal to scare others off their homes.
Zanzibar Giant Rat (Cricetomys gambianus) – IUCN Status – LEAST CONCERN. This is a species inhabiting the coral rag forest, common in Jozani forest but rare in other areas of Zanzibar. It reaches up to a meter in length, including the tail. The burrow sites are changed in two weeks to reduce the risk of predation.
Four-Toed Elephant Shrew (Petrodromus tetradactyla) – IUCN Status – DATA DEFICIENT – This is a species that inhabits primarily coral rag areas of Unguja Island in low canopy forests; under dry leaves, and non-flooding areas. It is rarely seen and survives because of its nocturnal lifestyle.
House Shrew or Indian Musk Shrew (Suncus murinus) – IUCN Status – LEAST CONCERN. This is abundant in Unguja Island. Its habitats are coral rag forest and non-flooding areas. It is an important food source for omnivores and carnivores. It is an exotic species from south Asia with a body length of 19 - 20 m.
Black and Rufous Elephant Shrew (Rhynchocyon petersi adersi) – IUCN Status – VULNERABLE SPECIES – FOUND INSIDE THE KIBELE PROJECT SITE PERIMETERS. The project zone provides a sanctuary to Rhynchocyon petersi (or Black and Rufous Sengi, Black and Rufous Elephant-shrew, Zanj Sengi). According to the International Union for Conservation of Nature (IUCN), the species is considered as VULNERABLE. The local population density of the Black-Rufous elephant shrew may be affected as the species is already under the IUCN list of vulnerable fauna. The Department of Forestry and Non-Renewable Natural Resources will provide environmental protection guidelines including compliance with the Zanzibar Forest Act16.
Lesser Bushbaby (Galago senegalensis zanzibaricus) – IUCN Status – LEAST CONCERN. This is a common species of Zanzibar and Africa as a whole. Its habitats are ground water forest, coral rag forest possibly mangrove forest. The lesser bush baby is distinguished from greater bush baby by its noticeable white patch stretching from forehead to nose. It is nocturnal.
Greater bush baby (Otolemur garnetti garnetti) – IUCN Status – DATA DEFICIENT. This is a common species in Zanzibar and Africa as a whole. In Zanzibar, its habitat includes the ground water forest, coral rag forest and possibly mangrove forest. It possesses a muscular body for its arboreal lifestyle. It is nocturnal.
Syke's monkey (Cercopithecus mitis albogularies) – IUCN Status – LEAST CONCERN - This is a common species in Zanzibar as well as in Africa. Its habitats are ground water forest, coral rag forest and mangrove forest. The species is seen daily foraging with Red colobus monkeys in plantation and ground water forests of Jozani forest.
African civet (Civettictis civetta) – IUCN Status – LEAST CONCERN. African Civet is listed as Least Concern because the species has a wide distribution range, is present in a variety of habitats, is relatively common across its range, is present in numerous protected areas, and has a total population believed to be relatively stable. It may, however, be undergoing some localised declines through hunting, including the off-take of wild animals (males) for the production of civetone, which is used as a fixing agent in the perfume industry.
Small Indian civet (Viverricula indica rasse) – IUCN Status – LEAST CONCERN. This is an exotic species and its secretions were used in perfume. Locally known as "ngawa", it is common throughout Zanzibar (i.e. Unguja and Pemba). Its habitat ranges from Ground water forest during the drought, coral rag forest and grassland. It is solitary except during breeding.
Zanzibar Duiker or Ader's Duiker (Cephalophus adersi) – IUCN Status – CRITICALLY ENDANGERED. Aders' Duiker occurs on the main island of Unguja, Zanzibar, as a near endemic. In Zanzibar, Aders' Duiker inhabits tall, undisturbed coral rag thicket known locally as msitu mkubwa of the Zanzibar-Inhambane regional mosaic (XIII). It is usually found singly, sometimes in pairs or trios and often, when encountered, may be following a troop of Sykes (Cercopithecus mitis albogularis) or Kirk's Red Colobus (Procolobus kirkii) monkeys feeding on discards and dislodged edibles from the canopy above.
Aders' Duiker appears to be loosely diurnal with a very acute sense of hearing and possibly smell. Aders' is a browser selecting for dicotyledenous leaves, seeds, sprouts, buds and fruits. Territories are maintained by facial gland secretions on prominent twigs and faecal heaps. In Zanzibar there has been a substantial amount of deforestation and forest degradation over the last 30 years. This has led to loss of habitat for Aders' Duiker, but also severe habitat fragmentation. Firewood is the primary source of income for a significant proportion of people living near the forest. Habitat destruction is probably the most significant threat to Aders' Duiker survival on Zanzibar.
Red-Legged Sun Squirrel (Heliosciurus rufobrachium dolosus) – IUCN Status – LEAST CONCERN. Its habitats range from coral rag forest to plantation forest. It differs from Red Bush Squirrel by possessing a black, ringed tail. It is absent in Pemba island
Red Bush Squirrel (Paraxerus palliatus frerei) – IUCN Status – LEAST Concern. It is a common species of Zanzibar and Africa at large, which in Zanzibar resides in coral rag forest and ground water forest. Its ecology is not well known. It is absent in Pemba island.
Avi-base, the World Bird Database has listed a total number of 276 bird species found in Zanzibar. About 6 species are categorized as endangered while 9 are exotic or introduced species.
VULNERABLE species include:
Cape Gannet (Morus capensis)
Pemba Scops-Owl (Otus pembaensis)
Southern Ground-Hornbill (Bucorvus leadbeateri)
Java Sparrow (Lonchura oryzivora)
NEAR THREATENED species include:
Eurasian Curlew Numenius arquata
Great Snipe Gallinago media
Fischer's Turaco Tauraco fischeri
European Roller Coracias garrulous
Fischer's Lovebird Agapornis fischeri
ENDANGERED species include:
Madagascar Pond-Heron Ardeola idea
Moheli Scops-Owl Otus moheliensis
Zanzibar is not known to having diverse amphibian species. There are studies by Pakenham on Amphibians and Reptiles of the Zanzibar and Pemba18 which show a total of 19 species or sub-species of amphibians found on Unguja. Lately, Amphibian species19 that have been trapped and recorded in the project zone during surveys carried out by other ESIA studies include Arthroleptis stenodactylus and Mertensorphrine micranotis. A new species of frog, Kassina Jozani20 was discovered in Zanzibar in 2006. This is an ENDANGERED species.
Historically, common reptiles found on Unguja Island include 10 species of lizards and 23 species of snakes (Pakenham:1983). However, since the publication of the study, not many detailed research works have been dedicated on reptiles in Zanzibar although there are some social media pages that attempt to document identified snakes. Sometimes it is hard to say whether the identified snakes are actually native to the geographical range of Zanzibar or they are somehow exotic and invasive. More studies specific to reptiles in Zanzibar are required to determine the current environmental and ecological status of the species. Common snakes found in Zanzibar as of recent records include the Green Tree Snakes, the Eastern Green Mamba, the Brown Snake, etc.
However, with respect to overall reptiles list for Zanzibar, a recent online database of reptiles whose range includes Zanzibar contains the following species:
Agama mossambica PETERS, 1854
Aldabrachelys gigantea (SCHWEIGGER, 1812)
Amblyodipsas polylepis (BOCAGE, 1873)
Aparallactus guentheri BOULENGER, 1895
Atractaspis bibronii SMITH, 1849
Broadleysaurus major (DUMÉRIL, 1851)
Cycloderma frenatum PETERS, 1854
Elapsoidea nigra GÜNTHER, 1888
Gastropholis vittata FISCHER, 1886
Hemidactylus angulatus HALLOWELL, 1854
Hemidactylus platycephalus PETERS, 1854
Hemidactylus puccionii CALABRESI, 1927
Hemidactylus turcicus (LINNAEUS, 1758)
Indotyphlops braminus (DAUDIN, 1803)
Lepidochelys olivacea (ESCHSCHOLTZ, 1829)
Letheobia lumbriciformis (PETERS, 1874)
Letheobia pallida COPE, 1868
Letheobia swahilica (BROADLEY & WALLACH, 2007)
Lycophidion acutirostre GÜNTHER, 1868
Lycophidion capense (SMITH, 1831)
Lygodactylus howelli PASTEUR & BROADLEY, 1988
Lygodactylus luteopicturatus PASTEUR, 1964
Lygodactylus picturatus (PETERS, 1870)
Mochlus afer (PETERS, 1854)
Phelsuma dubia (BOETTGER, 1881)
Philothamnus macrops (BOULENGER, 1895)
Philothamnus punctatus PETERS, 1867
Philothamnus semivariegatus (SMITH, 1840)
Sepsina tetradactyla PETERS, 1874
Uromastyx princeps O’SHAUGHNESSY, 1880
Marine And Coastal Ecology And Biodiversity
Sea Water Quality
Molly Moynihan (2010) carried out a study on how a rapid increase in Zanzibar’s population, as well as a lack of proper sewage treatment, water quality and eutrophication have become serious issues on Unguja21. These issues not only threatened public health, but also threatened the health of nearby coral reefs. When data from bacterial enumeration was compared with recommended levels of enterococci for safe recreational waters, values revealed that Stone Town’s water is unsafe for public swimming. Moreover, measured concentrations of ammonium from Chapwani Island exceeded those tolerable by healthy coral ecosystems. These results indicate that sewage pollution is causing, and will continue to cause damage to Stone Town’s waters unless a new method of sewage treatment is created.
As follow up to the above research in 2010, Socorro Lopez (2104) carried an extensive study on the environmental impact of fecal contamination on the Zanzibar Town’s marine environment22. Zanzibar Town is struggling to deal with the large amount of waste generated by growing populations and increasing tourist industries. In 2010, the waters surrounding Stone Town, a subsection of Zanzibar Town, were found to be highly polluted by fecal waste. Socorro’s study attempted to determine whether pollution has lessened or worsened in the past four years. Furthermore, environmental components of the coastal area, particularly tides, were tested in order to determine whether they had an impact on pollution in the waters. Results suggest that the pollution at both sites has worsened and continues to pose a serious risk to public health. Furthermore, spring and neap tides had a significant impact on enterococci concentrations, but how these environmental fluctuations influenced concentrations at the Port was not entirely clear. If measures are not taken in the future to improve the pollution in Stone Town’s coastal waters, there could be serious consequences to the local economy and the community’s health.
Studied around Chwaka Bay Area show a rich marine diversity. Seagrasses can function as habitat for a variety of organisms, including epiphytes such as microalgae, macroalgae, bacteria and a number of invertebrates such as echinoderms, crustaceans, molluscs, nematodes and polychaetes. The associated organisms within seagrass beds can affect seagrass ecosystem productivity and structure. Sceintists have reported the presence of about 11 species of seagrass communities around the Bay area, of which Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, Cymodocea serrulata, and Thalassodendron ciliatum are dominant species. Others are Syringodium isoetifolium, Halodule uninervis, Halodule wrightii, Halophila ovalis, Halophila stipulacea, and Nanozostera capensis.
Fish diversity around Zanzibar is high but the inshore banks have been deteriorating due to overfishing and destruction of coral reefs. A high density of small fish species also attracts concentrations of large predators making Zanzibar Channel as among best areas of game fishing. Fish are more abundant where there are healthy coral reefs.
Common Dolphin species observed around Zanzibar include Spinner Dolphin (Stenella longirostris), the Indo-Pacific Bottlenose Dolphin (Tursiop aduncus), and Indo-Pacific Humpback Dolphins (Sousa chinensis) which is categorized under IUCN Red List data Book as a Near-Threatened Species. Sperm and Humpback whales are regularly observed between July and November.
The species of sea turtle most commonly found in the waters around Zanzibar are the green turtle (Chelonia mydas), the hawksbill turtle (Eretmochelys imbricata) and the loggerhead turtle (Caretta caretta). Sea turtles are now classified as 'endangered' worldwide and Zanzibar's population of nesting sea turtles appears to be declining. The sea turtle population of Zanzibar appears to contain two components: a small nesting population, and a migratory population that feeds in Zanzibar but nests in other areas. Fishermen's estimates of the numbers of turtles nesting annually suggest that the nesting population (which consists of green and hawksbill turtles) have declined significantly in the last few decades, with signs of nesting activity being seen less than 10 times per year in the majority of areas.
Other marine species of IUCN importance in the geographical proximity include the Coelacanth (latimera chalumnae) listed as critically endangered. Coelacanths found around Zanzibar are thought to have originated from the Comoros, extending their range into the archipelago of Zanzibar.
A wide variety of sea birds are found around the shallow lagoons of the Indian Ocean in Zanzibar. Birds such as Sooty Terns (Sterna fuscata), Noddy Terns (Anoud stolidus), Crested Tern (Sterna begii) and masked booby (Sula dactylatra) are found on the sand banks, on the beaches, around inter-tidal flats and in the mangroves. Around a hundred species of birds have been documented from the Menai Bay Consrevation Area. These birds include Little Egrets, Cattle Egrets, Tellow Billed Egrets, Squaco heron, Night Heron, Purple Heron, Black Headed Heron, and Goliath Heron.