Interfaces of Miombo Woodland Biodiversity and Local Community: Woody Plant Species Use and Conservation Practices at Singida District, Tanzania
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Date
2005-07
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Addis Ababa Universty
Abstract
A total of 117 woody plant species representing 81 genera and 34 families (34.2% and 65,8%
shrubs and trees respectively) were collected and identified from the study area while 22 families
(70 species) were reported to be highly utilized by the local community. The area was dominated
by species of the family Fabaceae (26.5%) followed by Combretaceae and Rutaceae (11% each).
Brachystegici speciformis (IVI = 69.85) and Julbernardia globiflora (IVI = 51.2) were found to
be the dominant tree species. About 41% stems of woody species were found in the reserved but
not in the unreserved land where by 97.74% and 61.7% of this proportion were recorded as
stumps in the latter sites. 57.3% of the total woody plant species were highly utilized by the local
community. On the other hand, other useful species such as Aerva lanata, Boscia massaiensis,
Senna singueana and Lannea schweinfurthii var. stuhilmanii were locally extinct due to over
exploitation. TWINSPAN has revealed six plant communities based on relative disturbances at
various plots. There was a significant negative correlation between diversity and disturbance (r =
-0.456 p= .000) and between richness and disturbance (r = -0.318, p= .001). One Way Analysis of
Variance (ANOVA) has exhibited that the six communities were statistically different with
regard to their diversity (p = 0.000). Diversity was significantly high in the reserved area (p <
0.0001) but there was no significant difference among sample villages (p= 0.749). Similarly,
species richness has displayed a statistically significant difference (p= 0.0001) between the two
sites but no difference existed among the villages (p= 0.43). Moreover, Sorensen’s coefficient of
similarity has revealed high similarity in species composition (76.5%) between reserved and
unreserved land. With regard to structure, density was significantly higher in the reserved land (p
= 0.0019). Although both sites have portrayed a reversed J-shape trend student t test has revealed
significant differences among small reproductive trees (dbh class 10.1-20cm) (p=0.0186) and
among large reproductive trees (dbh class >20cm) (p= 0.0199) but no signinificant differences in
the poles (dbh class 4.1-10cm) (p= 0.1147) and seedlings and saplings (dbh class <4cm) (p=
0.5429) between the unreserved and reserved land. Stump density was significantly higher in the
unreserved (p= 0.0194) than the reserved land. On the other hand, tree basal area showed normal
J-shape trend but has exhibited a significantly high value in the reserved land (p = 0.0095) with
statistical differences p = 0.0011, p<0.0001 and p = 0.0279 among poles, small reproductive trees
and large reproductive trees respectively. Although the population structure of the study area has
revealed normal recruitment potential there was high degree of anthropogenic impacts. The mionibo woodland is currently being used in an unsustainable manner. The direct use categories
in the area are medicinal, firewood , charcoal, timber, building and fodder, beehives, food and
cultural. Most of these are also used to generate income at household level. However, local
communities were found to lack the appropriate knowledge of resource conservation and
sustainable uses. Furthermore, the traditional setup of the Sukuma people who are immigrants to
the area has posed negative impacts on the status of the woodland owing to increased human and
livestock population and land clearance for settlements and fanning . The current study has
revealed differences in the harvesting periods of useful woody species. Current conservation
strategies and practices have proved inadequate to combat the ongoing rate of destruction in the
area . Thus, there is need for deliberate efforts that will ensure sustainable use and conservation of
the resource via natural regeneration, enrichment planting and encouraging use of living fences.
It is important to explore new approaches that will attract people’s attention and interest on the
woodland and to involve majority of the local people in the planning and implementation of
conservation strategies. Each actor needs to realize that his/her operations have impacts on
sustainable development of the area. There is need to improve animal husbandry practices and
auction markets in the area and throughout the country. Moreover, deliberate programs should be
established to hasten the place of village boundary demarcation and prepare legalized land use
plans based on Participatory Land Use Management (PLUM).
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Keywords
Plant Species