Landscape influence on bee abundance and diversity in the forest savannah transition zone of Ghana and community knowledge of pollinators and pollination

Abstract

Global declines in pollinator diversity and abundance have been recognized, raising concerns about a pollination crisis of crops and wild plants. In many African countries including Ghana however research and publications on the subject are rare. To this end, a study was carried out from June 2013 to April 2014 to determine the influence of landscape type on bee species abundance and diversity in the Forest Savannah Transition Zone (FSTZ) of Ghana. The research also evaluated farmers’ knowledge and perceptions of the importance of pollinators and pollination. Two sites each of the landscape types; Agricultural land, Natural vegetation and Settlement fringes were sampled from three subzones selected on the basis of the proportion of trees relative to grasses. Overall, 706 bees made up of 3 families, 18 genera and 34 species were collected and identified. Apidae was the most speciose bee family and Megachilidae the least. Xylocopa, Amegilla and Lipotriches were the most common genera whilst Chalicodoma, Thyreus, Celioxys and Lithurgus were represented by single individuals. The results of bee species abundance and diversity were mixed for the various comparisons. Overall, the study indicated that bee species diversity is significantly influenced by landscape type and percentage tree to grass proportions (P ≤ 0.05). No such variation was observed for bee abundance probably due to the dominance of Apis mellifera Linnaeus. There were significantly more bee species in agricultural land and natural vegetation than in settlement fringes. Similarly, there were more bee species in the lower transition zone (area with the highest percent tree cover) than in either the middle or upper transition zone. Though most of the crop farmers interviewed had been farming for more than 10 years, they knew very little about pollinators and pollination, indicating the need to intensify education on the subject.