Specific concepts of fluvial ecology are well studied in riverine ecosystems of the temperate zone but poorly investigated in the Afrotropical region. Hence, we examined the longitudinal zonation of fish and adult caddisfly (Trichoptera) assemblages in the endorheic Awash River (1,250 km in length), Ethiopia. We expected that species assemblages are structured along environmental gradients, reflecting the pattern of large-scale freshwater ecoregions. We applied multivariate statistical methods to test for differences in spatial species assemblage structure and identified characteristic taxa of the observed biocoenoses by indicator species analyses. Fish and caddisfly assemblages were clustered into highland and lowland communities, following the freshwater ecoregions, but separated by an ecotone with highest biodiversity. Moreover, the caddisfly results suggest separating the heterogeneous highlands into a forested and a deforested zone. Surprisingly, the Awash drainage is rather species-poor: only 11 fish (1 endemic, 2 introduced) and 28 caddisfly species (8 new records for Ethiopia) were recorded from the mainstem and its major tributaries. Nevertheless, specialized species characterize the highland forests, whereas the lowlands primarily host geographically widely distributed species. This study showed that a combined approach of fish and caddisflies is a suitable method for assessing regional characteristics of fluvial ecosystems in the tropics.

The Ethiopian caddisfly fauna comprises 85 species, including 10 Oecetis species and three Lepidostoma species. In this context we provide the first species-level descriptions of Ethiopian caddisfly larvae. We describe and illustrate the larvae of O. mizrain and L. scotti, with additional notes on their habitats and distribution.

Cloeon perkinsi was described from South Africa in 1932 by Barnard. Despite being relatively common in Africa, it was mentioned in the literature quite rarely, and its known distribution to date includes most of sub-Saharan Africa. Material collected recently in Ethiopia, Israel, Saudi Arabia, and Yemen extends its distribution in East Africa, Arabian Peninsula and the Levant. We examined this material, and provide a re-description of adults (females and males) and nymphs of the species. It represents a much-needed urge mainly due to inconsistencies in literature reports regarding colouration, and sometimes incomplete morphological description of all stages. We demonstrate the intraspecific morphological variability that we have witnessed, and provide information regarding the range of habitats colonised by C. perkinsi. Based on geological and climatic history of the studied region, taken together with among countries genetic distances of the mitochondrial barcoding gene COI, we propose colonisation mechanisms for the north-easternmost limit of distribution. The fragmented distribution pattern of the species highlights the conservation importance of isolated aquatic habitats in the region, as well as current knowledge gaps.

An ecological study on the seasonal species composition and abundance of rodents was carried out in the farmland, bushland, forest and grassland habitats of Yerer Mountain Forest Area from July 2010 to March 2011. From a total of 3312 trap nights, 402 individuals of small mammals were captured. Out of these, 400 (99.5%) individuals represented 6 species of the family Muridae and whereas the remaining 2 (0.5%) belonged to one shrew species (family Soricidae). The seasonal species composition within each habitat was not significant. But there was significant variation in their relative abundance during wet and dry seasons. High mean trap success (23.5%) and biomass (4151g/hectare) was obtained from the farmland habitat. Number of pregnant females and embryo count showed seasonal variation. Stomach content analysis showed high proportion of plant matter in all samples.