Impact of habitat degradation on the assemblage of riparian ground beetles (Coleoptera: Carabidae) in the Morogoro Municipality, Tanzania

Abstract

This study assessed the impact of habitat degradation on the assemblage of riparian ground beetles in the Morogoro Municipality, Tanzania. The beetles were collected from three degraded (Ngerengere, Morogoro and Kikundi) and three relatively pristine streams (Bigwa, Vituli and Lukuyu) during the rainy season between January and April 2013. The beetles were collected by active searching on the ground, in leaf litters, under logs and stones. The abundance, species richness and diversity of the beetles were analyzed using Diversity and Richness ver. 2.65, PRIMER ver. 6.1 and SYSTAT ver. 10. The abundance of beetles was significantly high in relatively pristine streams (n=143) compared to the degraded streams (n=75; 34.4%) (Mann-Whitney U=4396.500; p<0.05). Metagonum sp.2, Peryphus sp.3, Boeomimetes ephippium, Abacetus sp.2 were the most abundant in relatively pristine streams while Diatypus uluguruanus, Metagonum mboko, Peryphus sp.3 were the most abundant in degraded streams. The highest species richness (S=21) was recorded in relatively pristine streams (s=21) while the lowest species richness (S=13) was recorded in the degraded streams. Furthermore, relatively pristine streams showed the highest average diversity (H′ = 2.5359) compared to the degraded streams (H′ = 2.0662). Based on the findings, ground beetles are good indicators of habitat quality. These results call for strengthened measures to control degradation of the riparian areas in the Morogoro municipality.