Browsing by Author "Ndunguru, Tabitha"

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    Influence of disturbance, habitat types and altitude on the abundance and diversity of dung beetles (coleoptera: scarabaeidae) in the east Usambara Mountain Forests, Tanzania
    (University of Dar es Salaam, 2006) Ndunguru, Tabitha
    The influence of forest disturbance, habitat types and altitude on the abundance and diversity of dung beetles was studied in the East Usambara Mountains, during the dry (September- October, 2004) and rainy seasons (April- May, 2005). Dung baited pitfall trapping was the method used. A total of 2225 and 2339 individual dung beetles (Scarabaeinae) representing 10 genera respectively were collected from the four forests of different levels of disturbance during the rainy and dry seasons respectively. There was a significant difference in abundance between levels of forest disturbance at P< 0.001. For both seasons there was a general decline in abundance and diversity of dung beetles with increasing level of disturbance. There was a significant variation in abundance of dung beetles between the three habitat types studied (forest, cultivated land and grassland) (P< 0.001) with the forest habitat having higher abundance than the cultivated and grassland habitats for both seasons. For both season (rainy and dry) the forest habitat had the highest diversity compared to the cultivated land and grassland habitats. For species that were collected in all of the three habitat types, their abundance decreases from the forest to cultivated areas and grassland. Food diversity, light intensity and moisture are among factors that may have influenced the abundance and diversity in these habitats. The influence of altitude on abundance and diversity of dung beetles was studied. There was variation in abundance of dung beetles between the altitudinal ranges (P< 0.001). Generally there was a decrease in abundance of dung beetles with increasing altitude. High level of disturbance caused by human encroachment, dominance of few species and higher rainfall has been suggested as the possible reasons for the variation in abundance. The dung beetles diversity increased with increasing altitude. Both abundance and diversity of dung beetles are affected by disturbance, habitat type and altitude. If the trend of forest destruction in the East Usambara Mountains is not reverted, a number of dung beetles may extinct from these forests. High, low altitude and grassland have been recommended in this study to be included in the ongoing long term monitoring programme.