Magesa, Debora M.2022-10-132022-10-132021http://www.suaire.sua.ac.tz/handle/123456789/4666Masters DissertationIntroduction Bees are known to be the most important group of insects. They are economically and ecologically important to humans. Bees provide various products such as honey, bee wax and bee venom on which human society depends for livelihood. Bees further provide pollination services to agro-ecosystems and natural habitats without which productivity in these ecosystems would not be possible. The diversity and distribution of bee species is determined by type, quantity and quality of suitable habitats in an ecosystem. Several studies have confirmed the influence of climate change on bee distribution. Bee species are expected to respond differently to climate change, either by range shift or disappearance due to loss of their suitable habitats. This study was aimed at assessing the distribution of bee species across habitat types and the influence of climate change on bee populations in the Kilombero SAGCOT cluster of Tanzania. Methods Stratified sampling was employed, where the stratification was based on habitat type. The habitat types were; Closed Forests (CF), Grasslands (GL), Woodlands (WL) and Agro- ecosystems (AE). Transects were established within the strata and plots measuring 20 m x 40 m (0.08 Ha) were laid along the transects. The distance between transects was 300 m and between plots was 200 m. Sweep netting and pan trapping were used to capture bees within the plots. At each plot identification and enumeration of each bee species collected was done. The identification was done later in laboratory using taxonomical keys. Bee species composition was determined as the list of the identified bee species. Euclidean distance measure of similarity and Raup-Crick dissimilarity index were used to compare the similarity/dissimilarity in bee species composition between the habitat types. Bee richness was determined as the number of bee species encountered, relative abundance of bee species was determined as the number of individual of each species relative to the total number for all species. Bee species diversity was determined by the Shannon-Wiener and Simpson Diversity Indices. Bee species evenness was computed by the Pielou's measure of species evenness, (J = H'/ln(S) where H' is Shannon Weiner diversity and S is the total number of species in a sample, across all samples in the dataset. Chi- square test was used to compare bee abundance and richness between habitat types. The influence of climate change on the distribution of dominant bee species was determined using Maximum Entropy (MaxEnt) modelling. The four most dominant bee species selected for modelling were; Apis mellifera, Meliponula ferruginea, Hypotrigona ruspolii and Liotrigona bottegoi. Pearson correlation was used to determine multicollinearity between the environmental variables. The environmental variable obtained after running multicorrelation analysis were; Bio11, Bio13, Bio15, Bio18, Bio19, Bio3, Bio4, Bio7 and Land cover. The highest scenario for GHG emissions (RCP8.5) was used for future prediction of bee distribution for the years 2050 and 2070. Response curves were used to determine the relationships between the environmental variables and the probability of occurrence of bee specie. Jackknife test was used to determine the variable of importance and percentage contribution of variable in influencing bee specie distribution. Findings A total of 818 individual bees, belonging to 169 species from five families were collected during the study period. The dominant family was Apidae and the least dominant was Andrenidae. Euclidean distance measure of similarity shows high similarity of bee species composition between woodlands (WL) and closed forests (CF). The bee species found in Grasslands (GL) were more similar to WL compared to bee species found in the Agro- ecosystem (AE). The bee species in AE were less similar to CF, WL and GL. Pairwise comparison show the habitat types which were significantly different in bee species composition were; CF and AE (p = 0.03), WL and AE (p<0.001) and WL and GL (p<0.001). Bee species abundance differ significant in all habitat types (Chi sq = 5.34; d.f = 3; p = 0.04). Shannon-Wiener Index of Diversity (H’) was highest in GL (H’ = 3.358) and lowest in AE (H’ = 2.012) while evenness was high in CF (E = 0.422) and lowest in AE (E = 0.141). This study revealed that bee species diversity, richness and abundance vary across the habitat types in Kilombero, thus potential implication on habitat conservation and bee species composition and diversity. Precipitation of the wettest period (Bio13) contributed to about 70% in influencing bee distribution on current and future climate change of highest emission scenario (RCP8.5) for the years 2050 and 2070. The study predicted that A. mellifera and M. ferruginea will lose their suitable habitats under future climate scenario of 2050 while H. ruspolii and L. bottegoi will experience slight gain in suitable habitats. Under the future climate scenario of 2070, all bee species will lose their suitable habitats. Conclusion There is apparently high bee species composition, richness and diversity in the Kilombero SACGOT cluster and the distribution varied across habitat types. Climate change has a significant influence on the current and future distribution of bee species in Kilombero SAGCOT cluster with precipitation of the wettest period being the main climatic variable influencing the future distribution of bee species. Loss of suitable habitats for most bees is the major future climate impact on bee population thus conservation of suitable habitats for bees is of paramount importance. Recommendation Mainstreaming these observations in the Kilombero Cluster Development Framework implementation of different cluster value chains, it is important if we should have sustainable production systems that consider both environment and agriculture production. There is a need to develop climate adaptation and mitigation strategies for conservation of bee populations in Kilombero which consider conservation of the potential areas where predictions show a reduction in habitat suitability for bees. Bee conservation under the changing climate needs to consider habitat connectivity to allow bee migration not only between current suitable habitats, but also to the future suitable habitats as predicted by the model. Long term monitoring in changes in the dominant bee populations is essential for predicting future climate change response. Given the potential influence of habitat type on bee populations, future studies should go further on studying the influence of vegetation composition on bee abundance and diversity and their interactions. Dissertation Structure This dissertation is in publishable manuscripts format, which consist of four main chapters. Chapter one comprise of the General introduction, Problem statement, Justification of the study and Objectives. The chapter two (Manuscript one) is on the assessment of bee species composition and diversity across different habitat types in Kilombero SACGOT cluster, Tanzania. The chapter three (Manuscript two) is on the influence of climate change on the distribution of dominant bee species in Kilombero SAGCOT cluster, Tanzania. The chapter four is on the general conclusion and recommendation of the study.enBeesClimate changeBee speciesSAGCOT clusterThesis