Mammalian Community Structure Varies With Distance Between Protected Areas in the Omo Valley, Southwest Ethiopia.

Rapid human population growth in Ethiopia has resulted in the degradation of vast areas of wildlife habitats due to agricultural expansion, infrastructure development, and urbanization. The Omo Valley in the southwestern part of Ethiopia has been particularly affected by land use changes, but despite its ecological importance, few relevant studies have been conducted there in the last two decades. Our aim is to provide updated and scientifically verifiable information for medium and large terrestrial mammal species richness and community structure in four Protected Areas in the Omo Valley. We used bycatch camera trap data from a large carnivore survey and nonparametric incidence-based estimators for data analysis. A total of 52 mammals from nine orders and eighteen families were recorded, of which approximately 29.4% are listed as globally threatened and one as an endemic subspecies. We present the current species lists and compare them with historical records and observed the highest species number in Omo National Park, even though nine species were no longer recorded there. We applied the Morisita-Horn similarity index to reveal a high degree of overlap in mammalian species among adjacent Protected Areas, but less overlap between Protected Areas far from each other, indicating distance decay of similarity. The distribution of feeding guilds was significantly different across Protected Areas, and carnivore detection frequency was relatively low in Tama Community Conservation Area compared to our other study sites. This study confirmed the conservation importance of the area in terms of mammalian diversity, albeit with low detection levels, especially of large carnivores, underscoring the importance of promoting landscape connectivity to maintain population viability across the Omo Valley. From our experience, the use of camera trap bycatch data proved to be effective in surveying large- and medium-sized mammalian species, but less so in capturing the rarer species in the area.