The Zanzibar clove industry

For about 150 years cloves have been a major export crop of Zanzibar. The industry was established through large plantations run with slave labor but these have been progressively fragmented into smaller holdings. Throughout this century the industry at home has faced several recurring problems, the worst of which are tree diseases, ageing tree populations and occasional neglect of trees. As a result, replanting has been crucial to the maintenance of the industry which has also been strengthened by government assistance. Overseas, Zanzibar faced little competition in the world clove market until recently and this is now being aggravated by increasing self-sufficiency in Indonesia. The future of the Zanzibar industry will depend on its ability to cope with the problems of the industry at home and on its success at selling cloves in an increasingly competitive world market.     

Farming Eucheuma in Zanzibar,Tanzania

5. Cultivation, tissue culture

Farming Eucheuma in Zanzibar, Tanzania     

The composition of the Josani Forest, Zanzibar

An analysis of the present composition of the Josani Forest, Zanzibar is discussed and the status of the forest considered. Particular interest is paid to those species used as food plants by the endemic subspecies of red colobus monkey, Colobus badius kivki Gray.
The forest is shown to have Calophyllum inophyllum L. and a species of Eugenia as co-dominants. The former species is considered likely to be indigenous to Josani, not introduced as presumed by previous authors. A number of species in Josani are found widely distributed on islands in the Indian Ocean, and the relation of Josani Forest to these insular floras is discussed.
It is tentatively suggested that the forest lies partially in a mature solution basin and that this has had an important influence on the present composition of the forest.     

Status and exploitation of the mangrove and associated fishery resources in Zanzibar

The distribution and growth forms of the mangroves on Zanzibar island (Unguja and Pemba) were investigated. Pemba island, with approximately 12000 ha of mangroves, had nine species; and Unguja island, with 6 000 ha, had eight. Average cropping intensities in Pemba island varied between 350–1937 cut plants per ha while in Unguja these were between 777–3567 cut plants per ha. In Pemba, mangrove forests were relatively less heavily exploited compared to those in Unguja, where clear felling was common. Charcoal, lime and salt production are the major activities which involve heavy utilization of mangrove wood.The fishery resources (shellfish and finfish) associated with the mangrove vegetation were also investigated by examining the composition of fish catches at landing stations in mangrove as well as nonmangrove zones of fishing districts. A survey on the fauna associated with mangrove forests was also conducted. A number of the local commercial fish species were found to be associated with the mangrove vegetation. The fishes of the genusLethrinus and the rabbit fishSiganus were found to constitute the bulk of the fish caught from waters adjacent to mangroves using movable traps. The molluscPyrazus sp., which is commonly used by the local people for food and bait, was found only in the mangroves.     

The burden of invasive bacterial infections in Pemba, Zanzibar

Background

We conducted a surveillance study to determine the leading causes of bloodstream infection in febrile patients seeking treatment at three district hospitals in Pemba Island, Zanzibar, Tanzania, an area with low malaria transmission.

Methods

All patients above two months of age presenting to hospital with fever were screened, and blood was collected for microbiologic culture and malaria testing. Bacterial sepsis and malaria crude incidence rates were calculated for a one-year period and were adjusted for study participation and diagnostic sensitivity of blood culture.

Results

Blood culture was performed on 2,209 patients. Among them, 166 (8%) samples yielded bacterial growth; 87 (4%) were considered as likely contaminants; and 79 (4%) as pathogenic bacteria. The most frequent pathogenic bacteria isolated were Salmonella Typhi (n = 46; 58%), followed by Streptococcus pneumoniae (n = 12; 15%). The crude bacteremia rate was 6/100,000 but when adjusted for potentially missed cases the rate may be as high as 163/100,000. Crude and adjusted rates for S. Typhi infections and malaria were 4 and 110/100,000 and 4 and 47/100,000, respectively. Twenty three (51%), 22 (49%) and 22 (49%) of the S.Typhi isolates were found to be resistant toward ampicillin, chloramphenicol and cotrimoxazole, respectively. Multidrug resistance (MDR) against the three antimicrobials was detected in 42% of the isolates.

Conclusions

In the presence of very low malaria incidence we found high rates of S. Typhi and S. pneumoniae infections on Pemba Island, Zanzibar. Preventive measures such as vaccination could reduce the febrile disease burden.     

Ecology of the Zanzibar Red Colobus Monkey: Demographic Variability and Habitat Stability

We examined the Zanzibar red colobus' (Procolobus kirkii) social structure and population dynamics in relation to the density, diversity and dispersion of food resources in ground-water forest and agricultural land, which we characterized in terms of red colobus food species density, diversity, basal area and dispersion. We used transect sampling and group follows to describe population dynamics and social systems. Two agricultural areas, SJF Shamba and Pete Village, had higher densities and more uniformly dispersed red colobus food tree species than those of the ground-water forest. Red colobus at these two sites had greater population densities and natality, and smaller home ranges than red colobus in the ground-water forest. However, these findings apply to a very small area of agricultural land (approximately 18 ha) that is contiguous with an area of the forest reserve having a high density of red colobus. It is not representative of agricultural areas elsewhere on Zanzibar which support much lower densities or no red colobus. Although agricultural areas contiguous with the forest reserve had high densities of red colobus, they appear to be very unstable. Within the agricultural areas, we observed higher intergroup variation in group size and composition, study groups that decreased dramatically in size and disappeared from the study site, significantly lower levels of juvenile recruitment, and red colobus food trees that exhibited definite signs of overbrowsing. This apparent instability in the subpopulation of red colobus utilizing agricultural systems probably reflects the lower basal area of food trees and the greater fragmentation of suitable habitat and floristic dynamics due to human activities in these areas. A fusion-fission social system occurred only in the ground-water forest subpopulation, which we hypothesize to be due to highly clumped food resources.     

Ecotourism and biodiversity conservation in Jozani–Chwaka Bay National Park, Zanzibar

This study is based on a study undertaken to assess how ecotourism has influenced biodiversity conservation in Jozani–Chwaka Bay National Park (JCBNP). It involved two communities surrounding the park, namely Pete and Kitogani. Field data were collected using structured questionnaires, key informant interviews and field observations. Questionnaires were administered to 76 households, whereas key informant interviews were conducted with foresters and JCBNP officials. Data analysis was undertaken using standard statistical methods. Findings from the study show that biodiversity management in the JCBNP has improved considerably after the introduction of ecotourism. The number of endemic colobus monkeys ( Piliocolobus kirkii ) and other rare species has increased. However, this achievement has been attained by restricting surrounding communities from using forest resources without providing alternative sources of livelihood. Findings also show that the benefits from ecotourism do not reach individual households, but the community as whole, in form of various social services. This has caused some resentment among the local people leading to their reluctance to reduce their direct use of ecosystem services available in the JCBNP, claiming that they cannot sustain their livelihood without such services. This has become a major source of conflict between the JCBNP and surrounding communities. Increased awareness and knowledge on biodiversity conservation would be needed for the communities surrounding the park to realize the potential and long-term benefits of ecotourism, and hence the need for their increased involvement in biodiversity management.