Impact of different grazing systems on diversity, abundance and biomass of beetles (Coleoptera), a study from southern Namibia
Publication Year:
Two plots were compared in the Nama Karoo, southern Namibia, in order (a) to test the impact of different grazing systems on arthropod diversity and abundance and, (b) to select suitable indicators of degradation for restoration efforts. On these plots, bushes and the grass Stipagrostis obtusa dominated on Gellap-Ost whereas Nabaos was strongly degraded with denuded soil. Compared to Gellap-Ost, this reduction in resource and shelter availability was reflected by reduced abundance and diversity but increased biomass of beetles (Coleoptera) at Nabaos. Especially in predatory carabid beetles, reduction in numbers seems to be compensated by the occurrence of larger species. A negative feedback for ecosystem functions was postulated from the lower arthropod diversity. Active management tools are recommended to restore Nabaos. Carabid beetles are best suited as indicators of grazing impact in the Nama Karoo ecosytem as they differ in species composition, diversity, and abundance between the plots, and belong to one of the taxonomically better known groups. Despite their great ecological impact, tenebrionid beetles are less well suited as indicators in this system as they differ in relative abundance but less in species composition. Furthermore, many of the tenebrionid species are undescribed and many tenebrionid groups are unrevised. Keywords: biodiversity, Nama Karoo, Tenebrionidae,rnCarabidae, Scarabaeidae, indicators.
Publication Title:
Zoosystematics and Evolution
Item Type:
Journal Article

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