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The island of Zanzibar, located off the coast of Tanzania, is home to a remarkable array of biota, largely due to its diverse range of habitats created by monsoonal climate patterns and unique geology and history. The conservation status of this biota is of concern due to high levels of deforestation and habitat degradation. There is limited taxonomic information on the majority of Zanzibar’s organisms, and thus management decisions are often made in a void of information. The Zoological Society of London (ZSL) in collaboration with the University of East Anglia and the University of Dar es Salaam has been working in the Zanzibar archipelago since 1995 and has recently begun a multi-disciplinary project aimed at understanding current patterns of biodiversity and the changing human/wildlife interface over time. As part of this project, we are summarizing the taxonomic and biogeographic information on Zanzibar’s terrestrial mammals. This paper represents part of a series and provides an overview of diversity, an assessment of the endemic status of Zanzibar’s mammals using a simple model, and an assessment of the conservation status of Zanzibar’s mammal communities.
The rocky insular nature of Zanzibar means that it has never been connected to the African mainland. This is responsible for its relatively impoverished mammal fauna. A total of 25 species of non-volant terrestrial mammals are listed for Zanzibar, 16 of which were doubtless present in “prehistoric” times. Three more species (unstriped ground squirrel Xerus rutilus, greater cane rat Thryonomys swinderianus, small spiny mouse Saccostomus campestris) are reported from Zanzibar, but appear to be recent introductions. The fauna is composed of a mixture of East African mainland and eastern arc elements and is poor in comparison to the latter. Generally speaking, the western and central parts of the islands support the most diverse and abundant mammalian populations. By far the most interesting of the forest species is the endemic red colobus monkey Piliocolobus kirkii. It is now confined to two small, isolated populations on Zanzibar and is classified as Endangered. The larger of the two populations is found in and around the Jozani Forest Reserve in the central east region of Unguja. The other population is found in the Kiwengwa/Pongwe Forest Reserve, which is isolated in terms of habitat and area. The red colobus was historically more widespread in the eastern regions. Its decline has been largely due to habitat destruction. The species was also heavily exploited for the Zanzibar monkey trade, in which young monkeys were captured and exported to Europe or America for zoos or as pets. This too has had a major impact on their population. Measures have been taken to help conserve the red colobus, and in 1992 a Recovery Programme for this species was initiated. This project is a joint effort between the Revolutionary Government of Zanzibar and a number of non-governmental organizations and research bodies. It aims to protect and enhance the red colobus populations that survive today.
Traditional hunting is suspected to be present and has had a culling effect on all types of animals, particularly the ungulates and some predators. This has not only affected mammals but birds as well. Educated Zanzibaris have stated that as all areas become settled and it becomes available, people will kill all types of meat for food. Remembering also the times of insecurity in Zanzibar’s history, the 1930s-1950s had many instances of lawlessness and periodic encounters with hostile forces. The final verification of the presence of Zanzibar’s lost and rare species can be made using indirect or direct methods outlined by Caro et al. (2001).
Surveys on relative abundance and personal observations suggest that in relation to the forests of the African mainland, Zanzibar has few species of indigenous large mammals and relatively low numbers of individuals per species. The environment of Zanzibar has been considerably altered by humans, particularly in the last 200 years. This has involved the clearance of large areas of forest and the serious degradation of those areas left. Clearance has had a direct impact on the largest-bodied mammals, and to this day there are elephant (Loxodonta africana) remains in the form of tusks stashed in caves on various islands off Zanzibar’s coast.
In recent decades, the conservation status of Zanzibar’s mammal species has changed significantly. Historical accounts suggest that, prior to colonization by the Arabs in 1698, the islands were home to a variety of large mammals (including elephant, buffalo, and antelope). However, intensive cultivation of the islands’ fertile soils and hunting of these animals for meat and sport led to their extermination. Most recent published accounts of Zanzibar’s mammals list only those species found within the last 100 years, since the islands were declared a British Protectorate in 1890. This has been further reduced over the past 50 years following the Zanzibar revolution in 1964 and the subsequent implementation of government policies to support people through redistributing agricultural land. The establishment of numerous clove plantations and smallholder farms has either directly removed forest and woodland habitat or disturbed the ecological processes essential for maintaining it. Large areas of the islands were also cleared of their natural vegetation to make way for export crops, especially cloves and coconuts. This has had a devastating effect on the islands’ mammal populations, with many species being unable to survive in the modified habitats.
Aders’ Duiker (Cephalophus adersi) is named after being discovered by Aders, a formerly well-known Conservator of Forests in Zanzibar. Very little is known of this species and is currently listed as critically endangered by the IUCN. The duiker is believed to be confined to only a few remnant patches of indigenous forest in the centre of Zanzibar and its distribution includes nearby Tumbatu Island. High human population density and increased land pressure in these areas pose a serious threat to its survival.
The Zanzibar Red Colobus Monkey (Procolobus kirkii) is the most notable of the terrestrial mammals on Zanzibar, and serves as an umbrella species for general conservation awareness for all Zanzibar’s fauna. This completely endemic species is now confined to only 10-20% of its historical range and remains one of the most endangered of all primates in Africa. This situation has been caused by the destruction of its forest habitat for agriculture and human settlement, and hunting for food and traditional medicine.
Zanzibar is home to some of the most unusual and unique species in the world. This can be said especially concerning the terrestrial mammals. Half of the current species of native mammals are ranked as the rarest and/or endangered in the world. The Zanzibar Red Colobus Monkey, Aders’ Duiker, Zanzibar Servaline Genet, Pemba Flying Fox, and Zanzibar Suni are all species that are endemic at Zanzibar and the surrounding islets. Unfortunately, there is an urgent need to conserve these species and their remaining habitats as most are under serious threat.
It has an extremely limited range on the main Zanzibar Island and is thought to be extirpated from much of this range. It occurs in greatest numbers in the southwest of the island, which is the location of the protected Jozani Forest. A small, introduced population is also present in the Kiwengwa/Pongwe Forest in east central Zanzibar. The species was once present in the Ngezi Forest on Pemba Island, but has long been extinct there. The primary reasons for the decline in Red Colobus populations are habitat destruction due to agriculture and human settlement, and hunting for meat and traditional medicinal remedies. During the 20-year period from 1987-2007, an estimated 50% of the original population was lost. This led to its uplisting from Endangered to Critically Endangered status. In 2016 it is estimated that only 1500-6000 individuals remain and, although there is strong protected area management in Jozani Forest, it is still uncertain whether these will survive.
The Red Colobus Monkey is the most distinctive primate on the islands, and it is somewhat surprising that it has led to much confusion. Early reports did not differentiate between the Zanzibar Red Colobus and the more widespread and less colorful Olive Colobus Monkey (Procolobus verus), which led to assumptions that it was a subspecies of the latter. However, it is now commonly accepted that the Zanzibar Red Colobus is a separate species, with notable differences in its coat color and a varied range of morphological contrasts. Like all colobus monkeys, it has a highly reduced thumb and a complex, chambered stomach that uses bacterial fermentation to break down cellulose.
The Zanzibar Red Colobus Monkey (Procolobus kirkii) is a little known, endemic species that is Zanzibar’s most threatened terrestrial mammal. They are found in tropical, coastal evergreen forests and coralline rag scrub. They are a diurnal and semi-terrestrial species occurring in social groups of up to 100 individuals.
It is likely that this species is under threat from habitat loss and hunting. Although there are still considered to be reasonable numbers on Zanzibar, it is mostly common in forested areas near cultivated areas, which are the same areas being heavily impacted by development. The East Pemba population is quite probably under threat, and that on Uguja would have been much more extensive had it not been for centuries of deforestation. Duikers are an important source of food and offer some protection from agriculture due to their restriction on consumption of crops and competition with livestock, and thus being largely considered as pests. This often leads to their persecution as they can be easily trapped in simple snares and are reluctant to move far from their home range even after disturbance.
Aders’ duiker is very similar to the more widespread and related Blue Duiker (C. monticola). It is a small, stockily-built duiker with a rough, short heavy coat and a more or less conspicuous erectile mane along the head and neck. The body is a uniform, brownish-red or rufous color which can be rather bright in younger animals. It was previously considered to be a subspecies of the Blue Duiker, but recent genetic analysis has shown it to be a distinct species and in 2005 it was formally named C. adersi. Duikers are difficult to census as they are rarely seen, being wary of humans and disturbing very little, and are almost exclusively found by dung surveys. During a recent survey in the Kiwengwa – Chwaka PAs, Aders’ duiker was primarily found in the Korongwe Forest Reserve with a few animals in the north of Kiwengwa village.
This small, forest-dwelling duiker is endemic to the Zanzibar archipelago, although the subspecific status of the Pemba population is not very well known. In general, duikers (of the genus Cephalophus) are solitary animals, foraging during the day and during darkness, mainly on fruit and sometimes on foliage or insects. They have a well-developed territory which is marked out with dung heaps, urine, and the secretion from their pre-orbital glands and latterly defended by if necessary.
Zanzibar Servaline Genet (Genetta servalina archeri) (Kock 1974) is a forest Genet subspecies endemic to Unguja Island. The validity of this subspecies has been questioned. Foss (1982) argued that it was no longer valid. This view was based solely on Kock’s description and not on any new data. Nevertheless, the Genet form on Zanzibar is very distinct. It is the most primitive of the forest Genets and has very primitive dentition when compared to other Genet species. The Zanzibar Genet is much larger and heavier than other Genets and has a very different coat pattern. The markings are more like a small Serval than a Genet in shape and size. It is a very aesthetically pleasing animal, but due to persecution it has become very rare. Only very few small patches of forest remain where it is safe from hunters. The Genet is a very elusive animal and is often mistaken for a small leopard because of its coat pattern. It is also arboreal and can often be seen high in the forest canopy. The forest Genets are the least known of Zanzibar’s terrestrial mammals. The Servaline Genet is the most unusual of the three species. The common Genet (Genetta genetta) has been introduced to the island within the past 100 years. Genets are members of the family Viverridae and are more closely related to mongooses and civets than felines. This can be hard to believe when observing a Genet as they have many cat-like qualities. The tail is very long and bushy, the body is slim and the limbs are long. Genets are hypsomorphic and have semiplantigrade feet, but the dewclaw is not raised off the ground. This is used for grip when climbing and is an adaptation to an arboreal lifestyle. Genets are solitary and nocturnal, feeding on small prey and fruit. Due to their elusive and nocturnal nature, a lot of the information regarding Genets has been obtained through radio tracking.
The Pemba Flying Fox, classified as a mega-bat, has a wingspan of 4 feet and is reddish-brown or black in color. Males are larger than the females and the young are born with golden fur. Their diet consists primarily of fruit with occasional blossoms, leaves or nectar. Research has shown that the two favorite types of fruit are the Indian almond and the mango. Hunting of the flying fox by local people, either for bush meat or in retaliation for damage to fruit crops, is the main threat to the species’ survival. Other threats include cyclone destruction of roosting habitat and disturbances to roost sites by foreign predators such as the mongoose and domestic animals. In recent years, much forest has been degraded very quickly. In general, native forest and all associated species are greatly threatened on Pemba by human population growth and the resulting increased pressure on natural resources. Much of the remaining forest is a protected area within the Ngezi Vumawimbi Forest Reserve but enforcement of protective regulations and community participation in conservation are minimal. Efforts to safeguard the flying fox and its habitat have been initiated in Pemba and it is hoped that this unique mammal can be saved from extinction.
The suni (Neotragus moschatus) is a small antelope no larger than a hare. It is generally found in thickets and often close to the coast of both Unguja and Pemba. It is unknown if this species is indigenous on Unguja as it has been reported that they were introduced from Pemba, however the suni is also known as Komoo Mbili in Swahili suggesting that it was originally found on Unguja. Hunting the suni was traditionally reserved for sultans and it is said that if anyone else killed one they were required to present the ears to the ruler as evidence that they had not killed a second animal. The Zanzibar red colobus monkey population has a significant effect on suni food sources. Red Colobus preferentially consume leaves and shoots of certain tree and plant species which is an important food source for suni and if these are over browsed the suni can suffer from competition and malnutrition resulting in a lower reproductive rate. The duiker are found in areas with very dense undergrowth and are commonly encountered in the Jozani Forest Reserve on Chwaka Bay, Marine Reserve on the central east coast. It is assumed that the Zanzibar duikers are the sole surviving members of a species that was once widespread over much of East Africa including the Kenyan coast and the islands of Zanzibar, Pemba, and Mafia and they have experienced a very significant decrease in range and population size in recent history. 100 years ago it was reported that the forest north of Chwaka Bay was so thick with duiker that one could scare them with a stick but most of this land has now been converted for agriculture and it is now rare to see a duiker outside of a protected area.
The Indo-Pacific humpback dolphin, locally known as “susu,” is the only member of the subfamily humpback dolphin. Although it is a species found in shallow coastal waters of the western Indo-Pacific oceans, it gives the distinction of being the only marine mammal species to be found in Tanzanian coastal waters. Historically, there have been two forms of humpback dolphins found in East Africa. The first was the Atlantic Humpback dolphin, which is now extinct, and the second is the Indo-Pacific. Although there are no longer any physical remains of the Atlantic variety, studies of old mammal collections from around East Africa showed that they were present up until the late 18th Century. The range of the Indo-Pacific humpback dolphin is quite extensive, stretching from the southern coast of China all the way down to the northern coast of Australia. However, throughout much of its range, especially in the northern regions, the dolphins are considered quite rare, and thus listed as “near threatened” on the IUCN red list. As with most cetaceans, little is known about the humpback dolphins of East Africa. They are usually found in small groups of less than 15, but there have been reports of larger aggregations in some areas. Studies carried out in southern Mozambique showed that there were distinct groups of dolphins that could be identified through photo identification. Lengthy surveys carried by boat or along the coast are needed to determine if the same holds true for the dolphins in Tanzanian coastal waters. Photo identification will also allow for population estimates, and potentially uncover information relating to individual movements and site fidelity. It is quite possible that humpback dolphins off the coast of Tanzania utilize the coastal waters around Zanzibar, including Menai Bay, as a nursery area. This assumption is based on the fact that the species usually gives birth in shallow, protected waters, and Menai Bay is already known to be a humpback breeding and calving area.
The Indo-Pacific humpback dolphin (Sousa chinensis) is found along the East African coast and in the Red Sea. Recent studies indicate that they prefer shallow waters less than 20m in depth, and for this reason have learned to coexist with humans, avoiding contact by moving into shallow water. The species shows a preference for enclosed bays, river mouths, and inshore waters and is essentially a coastal species. They are known to occur in small groups of up to 10 individuals, however, it is more usual for the species to be found in groups of less than 6. Little is known about the reproductive biology of this species. They have a gestation period of 10-12 months, and females give birth to a single calf. Life history characteristics of this species are thought to render them vulnerable to local extinction. This species is listed on the IUCN Red List of threatened species as “vulnerable”. It is considered that the major threats to this species are coastal development, habitat destruction, prey depletion, urban and agricultural pollution, boat traffic, disease, and entanglement in fishing gear. The species is known to have a high mortality rate from entanglement in gillnets. In Zanzibar, they are found in many locations around the main islands and around Pemba, where in the 1980s they were subject to a substantial directed fishery.
In Zanzibar, the term “jinici” is used to refer to both the dugong and the sea turtle, and there is no separate Kiswahili name for the dugong. In interviews with fishers, we always asked whether they had seen “jinici wa nyama” (a sea cow) and also showed pictures of a dugong and a sea turtle. We thus had to take some care in identifying reported dugong sightings. A frequent response was that fishers had not seen a jinici in a long time, or that their fathers or grandfathers had seen them. This could be due to the decline of dugongs in Zanzibar, but it could also reflect changes in jinici habitat or fishers’ reduced knowledge of jinici sightings since the time of their fathers or grandfathers. Because of this, we generally consider a reported sighting to be of questionable reliability unless the respondent gave a clear, credible description or responded positively to the picture of a dugong.
At the request of the State Department of Fisheries and Marine Resources, we studied the distribution and status of the dugong in Zanzibar for 12 days in February 2003. Our goals were to identify remaining seagrass bed habitats in Zanzibar, confirm the presence of dugongs, and make an initial assessment of the status of the Zanzibar dugong population. We used interviews with fishers and mapping of seagrass using local knowledge to identify potential seagrass bed habitat and confirm the species of seagrass in different areas. We conducted boat-based surveys in areas with potential seagrass habitat, looking for dugongs or their feeding trails and the presence of seagrass damage. Finally, we used fishers’ interviews and direct observation to make a preliminary assessment of the status of the dugong population. Due to limited time and resources, the survey effort did not achieve complete coverage of all areas where dugongs may occur, but we believe that it was adequate to identify all known areas with potential dugong habitat and to confirm the presence of dugongs in some of those areas.
In a more recent study in 2003 of dolphin distribution around the island of Zanzibar in order to assess the impact of increasing human population density on cetacean presence, a total of 147 sightings were recorded (72% occurring in Menai Bay). With spinner dolphins being sighted on 60 occasions, a general pattern could be seen of spinner dolphin preference for the more remote areas around Zanzibar and also Menai Bay. This could be due to lower levels of human activity and fishing in the area.
When comparing the spinner dolphin population numbers in Menai Bay to those in surrounding areas, it could be seen that the population was relatively low. In a 1997 survey of the waters surrounding southern Zanzibar, 83 dolphin sightings were recorded with spinner dolphins being sighted on 40 occasions. Enumerator-corrected estimates predicted a density of approximately 5 dolphins per km² over seagrass and a mean group size of 29 dolphins.
Located in the channel between Zanzibar and Dar es Salaam, lies the Menai Bay Conservation Area; an area which has been a focus for a number of studies in the past. In 2001, a comprehensive survey of cetaceans (whales, dolphins, and porpoises) was conducted using boat-based surveys which saw a total of 338 cetacean sightings. Among the seven species sighted, spinner dolphins were recorded in Menai Bay with the greatest frequency of 18 sightings.
False killer whales are large, oceanic dolphins that are difficult to observe in the wild as they usually shy away from vessels. They are known to inhabit offshore and pelagic waters in tropical and subtropical regions, but little is known about their abundance or distribution. False killer whales are one of the most social and communicative cetacean species and are known to form strong affiliations with other members of their pods. Studies from other regions have identified false killer whale populations using a variety of echolocation ‘dialects’ to distinguish between other populations, suggesting that pods have long-term connections. These dialects are also used for foraging coordination within a pod and studies have shown that shared foraging strategies are passed along generations and can be identifiable between different groups. Unfortunately, false killer whale populations have experienced several mass strandings in the past, including an event in Zanzibar where numerous individuals died after becoming stranded in Menai Bay. Strandings in other parts of the world have been attributed to by-catch of other pelagic fish.
Habitat loss and fragmentation are considered the most serious threat to Zanzibar’s indigenous wildlife, particularly mammals. Around 50% of the island’s forests were cleared between 1985 and 1995, largely as a result of agricultural expansion and fuelwood collection. Habitat loss can lead to small and isolated populations of species that are more vulnerable to chance events and inbreeding depression, and more likely to become locally or globally extinct. This trend has been noted in the Zanzibar red colobus Piliocolobus kirkii of which there are now only 1500 remaining and only 10% of these are found outside of Zanzibar’s protected area, with them being confined to just one area. A further consequence of habitat loss and that has been very damaging to Zanzibar’s forest is the invasion of exotic plant species. This was first noted in the 1940s in coastal areas where large areas of mangroves were cleared to make way for coconut plantations. The coconut farms were abandoned in the 1970s due to falling prices, disease, and poor soil conditions. The trees were either removed for timber or they were left and a new canopy developed. During a recent study at Jozani forest reserve, it was found that 23 exotic tree species were present, of which 10 were invasive. This has the effect of reducing the growth and regeneration of native species, and poaching may become easier as dense areas are opened up.
Habitat loss and degradation are cited as the primary threats to native mammal species in Zanzibar. Increased human population, urbanization, and subsistence agriculture have resulted in the widespread clearance of native forest and conversion of land to farmland. Agricultural productivity is low, so shifting cultivation is commonly practiced whereby land is cropped for a few years and then abandoned in favor of new areas. This has led to a landscape mosaic of regenerating forest and herbaceous vegetation, which although may appear diverse, frequently does not provide the necessities for long-term survival of forest-dependent species, such as the endemic Zanzibar Red Colobus (Procolobus kirkii). The construction of the clove tree (Syzygium aromaticum) plantations has had a disastrous effect on many of Zanzibar’s terrestrial species, as it is the favored cash crop and is grown on land traditionally left fallow in the Zanzibar Archipelago. Clove requires regular maintenance and does not provide sufficient cover or food sources for forest species. Habitat loss and fragmentation can lead to small, isolated subpopulations of a species in an area of degraded or secondary habitat. This has been the case for the endemic Zanzibar Suni (Neotragus moschatus), a small antelope which has lost large areas of habitat due to its forest being cleared for agriculture. The Suni is now confined to pockets of coastal scrub forest, and in some areas, it has been suggested that overpopulation has led to degradation of the habitat. Inadequate study of the Suni and many of Zanzibar’s species makes it difficult to assess the threats or ecological requirements for effective conservation.
The socio-economic drivers of these illegal practices mainly revolve around poverty and the high demand for meat. A study in 2002 by Kikula (as cited in Kulindwa 2004) found that more than 70% of rural households in Zanzibar lawfully consume wildlife meat and claim it is their preferred choice due to taste and health benefits. This is because access to domestic meat is cheap, and there is a declining supply of fish due to environmental degradation and competition with large-scale fisheries. Subsistence farmers often see wild animals as easy crop pests and destroyers and are uninformed about the laws protecting them from harm.
Poaching and illegal wildlife trade has been going on in Zanzibar for many years, and although the Zanzibar government has made it increasingly more difficult to export and import animals, the practice still occurs. From 1994 to 2002, a total of 217 mammals were captured and exported from Zanzibar. This primarily consisted of the Malbrouk Macaque and the Seychelles Aldabra giant tortoise, of which the latter was not actually taken from Zanzibar but was inbound for Comoros via Zanzibar. Many of the tortoises died during captivity in Zanzibar due to illness and lack of care. Since the time of this study, 3 individuals have been caught with Aldabra tortoises from Prison Island trying to smuggle them to mainland Tanzania to sell as exotic pets, of which one tortoise died from suffocation. By interviewing local people, it was uncovered that many types of illegal poaching go on in the protected areas, wildlife trade to complement the culture of hunting. This is most obvious at Kiwengwa/Pongwe forest reserve, where nets are set to capture the small suni antelope for meat, an age-old practice. During our research, we found evidence of active capture of the endangered Aders duiker to be sold for bushmeat. Old snares were found in Fuoni mangrove during the phase II study for the LCMP, and there is a report of government soldiers hunting the Zanzibar leopard in Unguja Ukuu managed forest reserve. From time to time, Zanzibar will also play host to poachers from mainland Tanzania who seek refuge from the law. In 2010, two were arrested in Uzi Island conservation area with twenty carcasses of suni, duiker, bushpig, and civet destined for Zanzibar.
Since the 1960s, nearly half of Tanzania’s wildlife has disappeared and the Zanzibar leopard is thought to be locally extinct due mainly to habitat degradation and human persecution. Currently, Zanzibar has 25 species of mammals, of which 3 are threatened, 4 are near threatened, and 1 is extinct (in parentheses): the Zanzibar leopard (extinct Zanzibar subspecies) (Panthera pardus adersi), the Pemba flying fox (near threatened) (Pteropus voeltzkowi), and the Kirk’s red colobus (Piliocolobus kirki). The remaining species are of least concern according to the World Conservation Union. Climate change is expected to lead to increased temperatures and highly unpredictable rainfall, which can negatively affect the abundance, distribution, and health of mammals. The Pemba flying fox is particularly at risk to changes in rainfall and tropical cyclone activity, and temperature increases may increase the spread of tropical diseases such as malaria. Sea level rise is a serious threat to the saltwater population of the Ader’s duiker found in coastal areas. High levels of tourism development along the East coast could lead to habitat loss for this species as well.
Protected areas are considered to be the cornerstone of mammal conservation. Here they are able to enjoy a safe environment, free from human-induced pressures. Being an island, the only type of protected area in Zanzibar is the state of a Marine Park. The importance that this park holds for the conservation of its mammals, dolphins, and the habitats upon which they rely cannot be underestimated. The Marine Park is a focus of global conservation interest, providing a living example of a complex marine ecosystem. It is the first park of this type in the Indian Ocean. Community-based efforts to conserve natural resources in Zanzibar have a long history. These efforts are typically implemented at the village level. The earliest examples of community-based conservation took the form of customary protection of particular forests or areas of bushland. Such protected areas were usually associated with sacred sites and were prohibited from destruction or use for timber or firewood collection. This tradition of customary protection continues to be an effective form of conservation in some areas, particularly in Pemba, associated with the preservation of sacred sites.
In 1959, the first conservation legislation that specifically addressed the protection of fauna was introduced. Since that time, a number of protected areas have been created on both Pemba and Zanzibar Islands, including reserves, forests, and marine parks. The network of protected areas is intended to help ensure the long-term survival of a number of wildlife species and their habitats. At present, over 45% of the total land area of both Zanzibar and Pemba is gazetted for nature conservation. However, these areas vary greatly in terms of their biodiversity value and the degree of active management that is being conducted to ensure the preservation of their natural assets. For a few sites, biological inventories have been produced to document the fauna and flora of the area. However, no comprehensive ecological assessments have been conducted, and management guidelines have only been developed for Unguja and Mnemba islands. The current political instability in the region, along with other social and economic factors such as expanding human populations and agricultural encroachment, continue to threaten the remaining natural ecosystems. This has led to a situation where the protected areas need to be reassessed in terms of their ability to continue conserving the nation’s biodiversity. Although a number of non-government organizations and bilateral aid donors are currently working on conservation issues, there is still a great need for a coordinated approach that is steered by the government and links conservation to the sustainable development of the nation.
Tanzania’s government ratified the Wildlife Policy of 1998 and the Wildlife Conservation Act (WCA) of 1974, which enforce policies for game control, hunting, protected areas, and regulation on protected species. This was a heavily penalizing policy for rural communities since it restricted access to their primary source of food and income, and increased human-wildlife conflicts. Inadequate enforcement and resulting habitat devastation in the earmarked ‘blocked’ wildlife areas led to divisions of WMAs. WMAs are usually found on village land, where villagers set aside and dedicate use of a particular area of their land for preservation and wildlife utilization. These areas are communally owned, and the village possesses the rights and responsibilities for management decisions and natural resource use. Income gained from these areas is used for the development of the village and conservation of the environment. Often excess income will be utilized to help alleviate the poverty that is the root cause of habitat degradation and overutilization of natural resources. The Kenya experience demonstrates the high level of interest in WMAs and their potential for land-use change in favor of wildlife. A study assessing land use changes in Kenya between 1977 and 1997 showed a 309-370% increase in land area allocated to wildlife compared to government-protected areas. This trend is expected to continue and expand in Kenya and is likely to have significant contributions to the conservation of biodiversity in Kenya, and in other countries if community-based programs develop in a similar manner.
To date, no long-term research programs on terrestrial mammals have been undertaken on Zanzibar. Most studies have been of short duration (generally less than 3 months) and were focused only on the species of the research team or on a specific question concerning multiple species. A project conducted by the Department of Commercial Crops, Fruits and Forestry (DCCFF) of the Zanzibar Ministry of Agriculture and Natural Resources began in 1999 and is ongoing. It is a study of the status and ecology of the Zanzibar red colobus monkey in Jozani Forest and at Uzi Island. The main purpose of the study is to assess the status of the Uzi Island population and to better understand how habitat structure and quality affect the abundance and ranging patterns of the species. The results of the study will be used to develop recommendations for management strategies to conserve the Uzi population and to ensure the long-term survival of the species on Zanzibar. Data collected during the study should also provide a better understanding of the ecology of the species and its conservation needs. This research program has potential to provide vital information for the management and conservation of one of Zanzibar’s most important and endangered mammal species.
Mammals are not a direct attraction to tourists, particularly when the coastal environments are rapidly decreasing in biodiversity and thus becoming less suitable for large wildlife (Kiffner et al., 2002). Zanzibar’s coastal forests and other areas of high biodiversity could act as an indirect attraction to wildlife enthusiasts if conservation efforts were shown to be effective. Package and luxury tourism is currently Zanzibar’s main focus, eventually the availability of these high-end tourist facilities can expect to draw specific interest to more natural and undisturbed areas such as wildlife reserves. If handled correctly, controlled and targeted tourism can have positive benefits to conservation through bringing revenue and increased awareness (Butler, 2003).
In the early 1990s, Zanzibar was visited by between 2000-3000 tourists annually (Bunoti, 1990 cited in Kikula, 1999). Since then, the government has identified tourism as a key factor for economic development, and an avenue by which rural communities can escape poverty (Kikula, 1999). The success of the current emphasis on tourism is indicated by 2005’s influx of 121,160 tourists (URT, 2007). As a result, expanding tourism is inevitable. This is reflected in the Zanzibar Commission for Tourism’s target of 500,000 tourists by 2012 (URT, 2007). Since most of Zanzibar’s attractions are coastal, future expansion of tourism has the potential to seriously impact terrestrial areas, particularly those of the East and South which hold the greatest mammalian diversity (Kumalo, 2003) amidst spreading human population. Approximately 15% of Zanzibar’s land area and most areas of high mammalian diversity are uncategorized in terms of land use, thus are open to future development (Kumalo, 2003).
Potential for mammal tourism in Zanzibar
It is clear that only the Ader’s duiker and Zanzibar red colobus are the two species of endemic mammal which are likely to provide focus for wildlife tours on Zanzibar at present. Fragmented data on Zanzibar red colobus at present suggests they are still quite widely distributed in small and large fragments of suitable forest throughout Unguja. Mangrove forests in southwest and central regions of the island also appear to support large troupes of Ader’s duiker. It is also clear from our data that without effective conservation measures the prospects for these and other wildlife on Zanzibar are bleak. In certain areas of Unguja visited during this study, local people reported that Zanzibar Red Colobus and Ader’s duiker are now only found in zoos. Evident increases in environmental awareness were also witnessed during this study, and it is clear that villagers have identified wildlife as an important resource which is increasingly under threat. This situation, combined with the potential for both resident and tourist demand for wildlife viewing, can form a basis for the development of wildlife tourism as a conservation tool on Zanzibar. At present, however, there are a number of obstacles which stand in the way of more formal wildlife tourism development. This includes a lack of wildlife management expertise and infrastructure, no official coordination between wildlife and tourism stakeholders, and poor relations between wildlife and local communities in many areas. Wildlife and habitat degradation and associated human-wildlife conflict are also a prime challenge, since it is clear that successful conservation of Zanzibar’s remaining wildlife will require persuading local people of both the short and long-term benefits of its existence.
6.2.2 Introduced species Since the middle of the 20th century, there has been a significant increase in the rate of introduction of alien species to Zanzibar. These species have been introduced mainly for agriculture, and include plants, invertebrates, and vertebrates. Alien plants are a significant threat to wildlife habitats in Zanzibar. Many have invaded large areas of forest and open ground, out-competing indigenous species and reducing the carrying capacity for some mammals. For example, the fast growing and dense tangle of Lantana camara which has become widespread in many of Zanzibar’s secondary forests, reducing their value to wildlife and people. A more recent and serious threat to the remaining wildlife areas is from alien invertebrates such as the giant African snail Achatina fulica and the African land snail A. marginata which are potential threats to endemic snail and other invertebrate populations. The most serious impact of alien species is from mammals, with the domestic cat being the most widespread and the small Indian mongoose Herpestes auropunctatus the most damaging. Introduced to Zanzibar to control rats in clove plantations, mongooses are now found at high densities in almost all remaining wildlife areas. Mongooses are efficient predators with a broad diet and are having a significant impact on ground nesting birds, reptiles, and small mammals. A study in Kiwengwa-Pongwe forest showed that mongoose activity areas had significantly reduced small mammal densities. An eradication program was started there in 2001 but was poorly funded and supported and was also impeded by local people who collect mongooses for food. Although a controlled mongoose population may be possible in the future, it is important to prevent further habitat loss and to continue with the restoration of areas where mongooses are present. Domestic dogs are also having a significant impact on wildlife through predation and transfer of diseases such as rabies and canine distemper. As in all issues involving humans and their activities on Zanzibar, conservation of the natural environment depends on education and changing people’s attitudes and activities.
6.2.1 Economic pressures Zanzibar’s rapidly increasing human population and the resulting urban and agricultural expansion has caused widespread habitat degradation and fragmentation. It has been estimated that 1.5% of the remaining forest on Zanzibar is lost each year and unless protective measures are taken, all of Zanzibar’s indigenous forest could be lost within 25 years (IUCN 2004). Apart from clearance, the remaining forest is severely overexploited. Livestock grazing and collection of fuel wood are widespread, and timber is still extracted in certain areas. Overharvesting of forest products results in damage to the forest and can be a threat to certain mammal species. Some of the most threatened areas for the remaining wildlife are those with the highest potential for tourism due to the unspoiled natural beauty. These areas are usually flat coastal regions with an elevated water table such as Kiwengwa-Pongwe forest and the remaining habitat patches between Uzi and Mchangani. This type of area is also prime land for agriculture and human settlement and is therefore under great threat from land-use conversion, mainly for the cultivation of rice and vegetables and new settlements for immigrant farmers from other parts of Tanzania. The recent need for Zanzibar to increase food production due to increased population and reduced reliance on food aid from the mainland will put further pressure on these areas. An example of this is Chwaka and Fumba where the future intention for agricultural expansion is likely to cause fragmentation of the remaining forest and much of the surrounding wildlife areas. With an increasing human population and a stagnating economy, the government is unlikely to implement protectionist land use policies without substantial financial compensation to the people affected.
Protection of the remaining wildlife outside forest areas, particularly in agricultural land, may be essential to ensure the survival of many species. It may be necessary to establish conservation areas specifically for such species, and in some cases translocation and captive breeding programmes may be needed. Detailed studies on the ecology and behaviour of such species will be required to assess their specific habitat requirements and the effectiveness of any future conservation measures. This concept also applies to the two species of Pteropus bats on Zanzibar, which are thought to be extinct but may still survive on Pemba Island. A survey should be carried out on Pemba to confirm the presence of the bats and if successful, a captive breeding programme may be an option for the re-introduction of the bats to a protected area on Zanzibar.
It is recommended that future research and action should focus on the conservation of the remaining fragments of forest on Zanzibar, particularly in Jozani Forest, which is the focus of much of the remaining wildlife. Priority should be given to the protection of areas with high biodiversity and endemic species, where there is most threat of habitat destruction, and monitoring programmes should be established to evaluate the effectiveness of protected area management. The forest fragments of Zanzibar are under constant threat from agricultural expansion, illegal logging and fuelwood collection, and it is essential that methods be implemented to reduce human impact in these areas, such as promoting alternative fuel sources to wood.
