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5.3.4 Data analysis methods and procedure
All those who generated quantitative data analysed it statistically but some observational studies did not have any statistical treatment. The rigorous nature of the analysis depended on the type of information and also on the
hypothesis being tested. Masawe 1999, Germanis 1999 and Shunula 1996 for example evaluated their data statistically using the MINTAB Statistical Software Programme. Almost all the compilation and computation work by
Mattia 1997 was done using the spreadsheet software, QUATRO PRO. Also simple statistical calculations such as means and standard deviations were used to describe the structure of the forest.
Machiwa 1999 in his study in the Maruhubi mangrove forest used parametric one-way analysis of variance ANOVA to test the difference in his measurements in the different zones of the forest. He also used Tukey test
to compare sample means. Besides using ANOVA, Germanis 1999 also used Fisher’s pairwise comparisons of means. The F test was used to compare the amount of methane produced by the different types of mangrove leaves
and other soluble substrate i.e. acetate, formate and trimethylamine TMA Julius 1998.
5.4 Qualities, usefulness and reliability of datainformation
Studies conducted by qualified researchers and M.Sc. or Ph.D. students are the most reliable. These follow research protocol very closely and for the M.Sc. and Ph.D. studies, there are various mechanisms put at the
University to control the quality of the work.
Tanzania mainland has produced very comprehensive reports on mangroves, their distribution, uses and suggested management plans Semesi 1991 b-l. This inventory of the mainland covers practically all mangrove resources,
their species composition and wood quality with a separate detailed report for each region. The reports are a very useful tool for planners and decision-makers. On Zanzibar the Ministry of Agriculture and Livestock and Natural
Resources Commission did a mangrove inventory.
5.4.1 Duration of studies
The duration of studies varies, from a few days, months, and years. The longest studies are those connected with the Ph.D. and M.Sc. studies by McCusker, Shunula, Mohamed, Lyimo, Machiwa, Julius, etc., those in connection with
the preparation of management plans and also those done in the early 1900 in connection with mangrove planting at the Rufiji delta.
5.4.2 Capability of scientistsresearchersreporters
Most of those who were able to publish their results are capable researchers. However, a lot of some of the information in grey literature is collected by people who are not necessarily capable reporters or researchers.
Some of the work is part of field reports by undergraduate students and field officers.
5.4.3 Comparability of methods
Methods used are those recommended in the literature but sometimes modifications had to be made to suit the local conditions.
5.4.4 Publicationsgrey literature
About 24 percent of the literature is in refereed Journals, 17 percent is in published proceedings, 28 is in special reviews and Management plans and 19 is in grey literature table 1.
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Table 5.1: Distribution of literature on mangroves of Tanzania in various categories.
Category Number of items
International refereed journals 32 24
Published conference proceedings 23 17
Special reports UNEP and UNESCO series and technical reports e.g. management plans, Frontier
series etc. 37 28
Books or book chapters 5 4
Unpublished reports 25 19
Ph.D. theses 5 4
M.Sc. theses 6 5
Total 133
In total there are 5 Ph.D. and 6 M.Sc. theses written on the mangroves. Four of the M.Sc. theses i.e. by Masawe, Nasser, Germanis, and Mkomwa, are not to be found in the University Libraries in the country and hence are
inaccessible to readers in the country. Therefore because of the inaccessibility of information, the literature listed may have been seriously under estimated.
5.4.5 Age of information oldrecent
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