Large Mammal Diversity in Nensebo Forest, Southern Ethiopia
Research Article | Open Access: by Zerihun Girma and Zerubabel Worku,
Hawassa University, Wondo Genet College of Forestry and Natural Resources, Department of Wildlife and Protected Area Management, Shashemene, Ethiopia GIZ-Biodiversity and Forestry Program (BFP), Addis Ababa, Ethiopia
There is a lack of information on mammalian faunal resources of remote forests in Ethiopia; as a result, the findings of the research on large wild mammals at Nensebo forest is one of the steps in a continuing effort to document and describe the diversity and distribution of Ethiopian mammals in remote and less accessible forests. The survey was conducted to assess the species composition and relative abundance of large mammals. Two standardized survey techniques, direct (sighting/hearing) and indirect (scat/footprint), were employed using systematically established transect lines and field plots in two dominant habitat types (modified moist Afromontane forest and intact moist Afromontane natural forest) of the study area. A total of 16 species were recorded including two endemic mammals, namely, Tragelaphus buxtoni and Tragelaphus scriptus meneliki. Abundance of species among different habitat types was not significantly different (χ2 = 0.125, df = 1, ), and Colobus guereza was the most abundant species. In contrast, Felis serval, Panthera leo, and Tragelaphus buxtoni were the least abundant species. The highest diversity index was recorded in the natural forest habitat (H′ = 2.188), and the modified forest had the lowest diversity index (H′ = 1.373). There is an urgent need to minimize threats and mitigate impacts.
Mammals provide ecological, economic, sociocultural, and educational and scientific services in a particular ecosystem [1–6]. They are one of the most widely distributed organisms in the world. Mammals are successful in colonizing diverse habitat types due to diversity in morphological, physiological, and behavioral adaptations and hence exist from the Antarctic to desert regions [6, 7]. They exhibit great diversity in size and forms. Particularly, range from the smallest Kitti’s Hog-Nosed Bat (Craseonycteris thonglongyai) (2 g) to the giant blue whale (Balaenoptera musculus) (140,000 kg) . Those that weigh above 7 kg are called large mammals [1, 8]. There have been discoveries of new taxa over the past decades; as a result, the number of mammalian species has been continuously updated. According to the most recent (3rd) edition of the standard taxonomic reference work, Mammal Species of the World , the class Mammalia comprises 5416 species. The largest groups are rodents (Rodentia, 42%), bats (Chiroptera, 20.6%), and their Allies (Soricomorpha, 7.9%).
Ethiopia is one of the top 25 biodiversity-rich countries in the world, and hosts two of the world’s 34 biodiverse hotspots, namely, the Eastern Afromontane and the Horn of Africa hotspots [9, 10]. It is one of the countries with the most diverse mammalian faunas in Africa [6, 7]. It is estimated that there are about 320 species, including 39 endemics (both small and large mammals), distributed in 14 orders and 39 families [11–13]. Furthermore, the country is known as “Home of the Unique Seven” which refers to seven distinctive and large endemic mammals found only in Ethiopia , namely, the Ethiopian wolf (Canis simensis), mountain nyala (Tragelaphus buxtoni), walia ibex (Capra walle), Menelik’s bushbuck (Tragelaphus scriptus meneliki), Swayne’s hartebeest (Alcelaphus buselaphus swaynei), gelada baboon (Theropithecus gelada), and bale monkey (Chlorocebus djamdjamensis) [13, 14].
A number of large mammal diversity studies have been carried out in various protected areas of Ethiopia [15–18]. However, the faunal records of the country are underestimated since most studies have focused on protected areas , where large mammals are mainly concentrated in the south and southwest border and adjacent area. Several reports have also emphasized the importance of habitats outside protected areas in supporting large mammal diversity, but there have been few surveys of these sites and comprehensive baseline information is lacking . However, protected areas alone cannot sustain large mammals. First, only a small proportion (186,000 km2, equivalent to 16.4% of Ethiopia’s surface area) of Ethiopia’s landmass is legally protected . Second, large mammals often travel long distances outside of protected areas to fragmented forest patches due to seasonal variations of resources. As a result, wildlife depends on land adjacent to these protected areas for continued viability. They may use these adjacent lands as critical dispersal areas, calving grounds and/or for other seasonal movement between protected areas. However, there has been little understanding of how the ecosystems function and large mammals survive especially in human dominated landscapes.
Nensebo forest, a patch of moist Afromontane forest (MAF), is partly connected to the Bale Mountains National Park (BMNP). However, this corridor has continued human encroachment that often challenges wildlife movement between the two areas of habitat. Large mammals such as mountain nyala and lion (Panthera leo) may move seasonally between these two habitat areas. However, there is no scientifically documented information about which large mammal species are restricted to the forest area, which are the most abundant, or on population structure or habitat use of resident species. Likewise, there is a need of information on the species diversity for the large mammal population to underpin management actions and integrate sustainable conservation of the wildlife resource in BMNP and forest fragment.
The aim of the present study was therefore to describe the species composition, relative abundance, and population structure and habitat use of large mammals in Nensebo forest to underpin future management.
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