Climatic, Regional Land-Use Intensity, Landscape, and Local Variables Predicting Best the Occurrence and Distribution of Bee Community Diversity in Various Farmland Habitats in Uganda

M B Théodore Munyuli

doi:10.1155/2013/564528

M B Théodore Munyuli

Open Access

https://doi.org/10.1155/2013/564528

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Abstract

This study was conducted in 2006 in central Uganda to provide baseline data on relationships between bee community variables and local, climatic, landscape and regional drivers affecting bee community abundance and diversity in agricultural landscapes. Bee abundance and species richness increased significantly () with increase in percent cover of semi-natural habitats and the abundance of wild and cultivated floral resources in the landscape. There were strong linear declines () in bee species richness and abundance with cultivation intensity. Bee species richness declined very steeply with forest distance. Bee species richness and abundance were negatively affected by land-use intensity (). Bee species richness and abundance were strongly negatively correlated () with increase in mean annual temperatures in the previous years than in current years indicating potential vulnerability of local bee species to future climate changes. The percent cover of semi-natural habitats and natural in the farmland predicted best the occurrence and distribution in central Uganda. It is therefore recommended to policy-makers and to farmers to invest in the protection of forest fragments (and related semi-natural habitats) acting as buffer in the mitigation of negative effects of climate change on bee biodiversity and pollination services delivery.

Highlights

Pollinators provide a crucial ecosystem service through their role in the sexual reproduction of both wild plants and crops [1,2,3]
Species richness of wild blooming plants increased linearly with increase in % cover of semi-natural habitats (R2 = 0.293, n = 26, P < 0.001) but declined linearly with forest distance (R2 = 0.455, n = 26, P < 0.001). These results indicated that isolated sites or overcultivated sites were associated with low species richness in flowering plant species at some times, abundant mass blooming crops could be observed in overcultivated areas or in areas located very far from forests
The number of wild blooming plant species accounted for 19.6% of variation in bee species richness. These results indicated that increase in the diversity of flowering plant species can attract a high number of bee species; beyond 30 plant species, bee species richness can start to drop

Summary

Introduction

Pollinators provide a crucial ecosystem service through their role in the sexual reproduction of both wild plants and crops [1,2,3]. There exist multitude factors (pressures), but currently suspected drivers (working alone or in synergy to produce negative or positive impacts) with potential effects (e.g., likely causing decline) in bees include land use change, use of pesticides (pesticide exposure) and reductions in population genetic diversity, farming and farm management practices changes, habitat loss and fragmentation, introduction of non Psyche native invasive species, species competition for resources, parasites and pathogen spread, heavy metal pollution, and climate change [9, 11,12,13] Interactions between these multiple factors and various other factors are likely; for example, nutritional stress, due to a lack of floral resources or their poor quality, may lower the tolerance of pollinators to pesticides and diseases [14]

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