Characteristics of bee fodder plants of mlele beekeeping zone, Katavi, Tanzania
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Date
2024-05
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Sokoine University of Agriculture
Abstract
Pollination by insects, particularly bees, is essential for biodiversity
conservation and plant reproductive success. Tanzania is
characterized by a rich diversity of flowering plants estimated to be
over 9000 species. A wide variety of flowering plant species serve
as bee fodders and are essential to maintaining healthy bee
populations. Mlele District in Katavi region of Tanzania is among the
highest honey producing area in the region. Several studies on bee
fodder plants characteristics, including their composition and nectar
quality have been done in temperate and sub temperate regions with
few in the tropics. These studies have reported the impact of
environmental and human disturbances on bee fodder plants.
Despite the potential of Katavi region for beekeeping, few studies
have been done in the region, especially on the characteristics of
bee fodder plants incorporating environmental, disturbance and the
nectar quality. This knowledge gap results into ineffective
conservation of food sources for bees, unsustainable beekeeping
practices, low production and quality of bee products.
The study overall objective was to determine the characteristics of
bee fodder plants of Mlele Beekeeping zone. The study included two
objectives, the first objective was to determine the composition of
bee fodder plants along environmental and disturbance gradients
and the second was to determine the periodicity of floral rewards by
the bee fodder plant species. A systematic sampling design was
employed to assess how environmental and disturbance gradients
impact bee fodder plants composition. A total of 50 rectangular plots
of size 50 by 30 m were laid in two transects with 25 plots in each
transect. Plant flowers were observed for 10 minutes and were
scored as bee fodder plants after at least three bees visited the
flower within the observation period. The periodicity of floral rewards
objective employed purposive sampling design on the basis of
provision of measurable amounts of nectar and enough flowers to
conduct the study with repeated measurements. Plants in which the
honeybees extended their proboscis into the flowers were determined as nectar rewarding plants and where bees collected
pollen were determined as pollen rewarding plants.
Data collection on bee fodder plants composition was obtained
through a summary of species data list and their abundance values.
Climatic data was obtained from the current climate data set
downloaded from world climate site with a 30 arc seconds resolution
and four subsets of biophysical data were used. Disturbance data
was recorded for presence or absence and the disturbance type.550
hours of observation were made for recording of flower visitors on
ten bee fodder plant species from 0700 hours to 1800 hours. Nectar
was extracted by micro capillary tubes and quality was measured in
form of total sugar concentration by the use of a digital handheld
refractometer.
In the data analysis section, data skewness was addressed by
standardization of the data. Detrended Correspondence Analysis
(DCA) was applied to assess the ecological gradient's magnitude
within the species composition matrix and to determine the
appropriate constrained ordination method. The results gave the
option for Canonical Correspondence Analysis (CCA) due to the
data's heterogeneity. Log-transformations were applied to species
abundance data to meet multivariate normality assumptions. Rare
species occurring in fewer than five plots were excluded from the
analysis. Stepwise automatic forward selection identified significant
explanatory variables for CCA. The chosen variables were then
constrained against tree species and community composition.
Permutational Multivariate Analysis of Variance Using Distance
Matrices (Adonis) was employed for variance partitioning. The
community composition was identified by the use of Bray-Curtis’s
dissimilarity and Silhouette validation. Generalized linear models
were created to examine visitations and effect of nectar
concentration and temperature on bee visitation rate.
Overall, 71 bee fodder plants belonging to 25 families were
recorded. The results revealed that 23% of the variation in the composition of dominant tree species within the study area could be
attributed to the interplay of environmental and disturbance factors.
Elevation emerged as the most influential predictor, accounting for
approximately 11.6% of the total variation. Annual mean
temperature contributed around 3.5% to the observed variation and
annual precipitation about 3.6%. Four bee fodder plant communities
were identified in the area with first cluster being dominated by
Erythrophleum africanum, second with Brachystegia glaucescens,
third with Diplorhynchus condylocarpon and fourth Bobgunnia
madagascariensis. Nectar concentration was identified as a central
driver of bee visitation patterns. The bee fodder plants including
Antidesma membranaceum and Friesodielsia obovata, showcased
nectar concentration percentages that significantly enhanced their
attractiveness to bees.
The results of this research study have the potential in providing
valuable insights to beekeepers and conservationists for improving
beekeeping practices in Mlele Beekeeping zone. It provides
understanding into factors influencing bee visitation rates to different
bee fodder plant species. It also highlights the significance of nectar
sugar concentration and temperature in shaping bee foraging
behavior. Environmental factors particularly elevation, annual mean
temperature and annual precipitation are seen to be important in
shaping the composition of bee fodder plants. The findings
recommend prioritizing and promoting planting and conserving bee
plant species with high visitation rates such as Antidesma
membranaceum, Psorospermum febrifugum and Securidaca
longepedunculata to support bee populations and enhance
pollination services.
Further research is needed into other bee fodder plants traits that
attract bee to deepen our understanding of bee interactions.
Understanding the relationship between environmental factors and
bee plant communities in other locations and other factors such as
soil type and land use should be considered. As ecosystems face ongoing challenges from climate change and human activities, such
research becomes increasingly valuable in ensuring the health of
bee populations and the preservation of biodiversity. Further
research in other regions and at different scales is needed to expand
our knowledge of these vital relationships and their implications for
beekeeping and conservation efforts globally.
Description
MSc Dissertation
Keywords
Pollination, bees, floral resources, nectar quality, composition, beekeeping