Abstract
Studying
small mammals has a paramount significance for ecological, cultural and
economic reasons. A survey on the diversity, abundance and habitat
association of small mammals in Wenchi highland, central Ethiopia, was
carried out from August 2019 to January 2021. Small mammals were trapped
from six different habitats (Hagenia Woodland, Erica Scrub, Qibate,
Lakeshore, Erica and Albesa Forests) using Sherman and snap traps in
standard trapping grids. A total of 935 rodents belonging to 12 species
(Arvicanthis abyssinicus, Desmomys yaldeni, Mastomys natalensis, M.
awashensis, Stenocephaylemys albipes, Lophuromys flavopunctatus, L.
brevicaudus, L. chrysopus, Dendromus lovati, Lophiomys imhausi,
Graphirius murinus, and an unidentified murid rodent), and 24
insectivores belonging to 3 species (Crocidura bailey, C. fumosa and C.
olivieri) were recorded. Hystrix cristata and Tachyoryctes splendens
were also recorded through indirect evidences. About 52.9% of the
identified small mammals were endemic to Ethiopia. A significant
variation was observed in the captures of small mammals. The capture
rate was higher in live traps (23.85%) than snap traps (8.26%). The
diversity and distribution of small mammal species varied among
habitats. The highest species diversity (H’=1.74) was recorded in Albesa
Forest, while the least was in Qibate Forest (1.43). The highest number
of individuals were recorded in Lakeshore Forest (27.73%), whereas the
least was in Erica Forest (4.27%). M. natalensis (30.86%) and S.
albipes (27.53%) were the two most abundant species, whereas L. imhausi
(0.1%) was the least. Wenchi montane forests are one of the most
important homes to unique small mammals that need urgent conservation
actions.
Keywords: Abundance, Species diversity, Habitat association,
Montane Forest, Small mammals, Wenchi highland
Introduction
Small mammals are the most diverse group of mammals, but yet little
information is known about them compared to larger mammals (Kumaran et
al. 2016). The study of these animals, however, has paramount
implications for ecological, cultural and economic reasons (Torre 2004;
Marques et al. 2015). Rodents are a group of small mammals with nearly
worldwide distribution (Kingdon 1997). Rodents are important components
of natural systems that aerate the soil and assist plant propagation,
food base in food chain, and dietary components for many predators
(Tobin and Fall 2004; Yihune and Bekele 2012). Some rodents are model
organisms for ecological studies and serve as good indicators of
environmental quality (Habtamu and Bekele 2012).
Rodents are also an important food source for humans (Habtamu and Bekele
2008; Meyer-Rochow et al. 2015). In contrast, rodents are major pests of
agriculture, and involved in the distribution of many pathogens (Yihune
and Bekele 2012; Garba et al. 2013). In this sense, their presence in
crop fields, houses and/or around human dwellings is devastating rather
than regulating nature (Tobin and Fall 2004). The economic and
ecological benefits of rodents, however, outweigh these destructive
effects (Habtamu and Bekele 2012).
Ethiopia harbors a much higher endemic mammalian species than any other
African countries (Lavrenchenko and Bekele 2017). The order Rodentia
alone contributes most of the total endemic mammalian fauna of the
country (Kassa and Bekele 2008). It is still presumed that the species
diversity and level of endemism could be far higher than this
(Lavrenchenko and Bekele 2017). Most of the ecological studies on small
mammals in Ethiopia are also largely restricted to the protected areas,
like that of larger mammals (Habtamu and Bekele 2008; Workeneh et al.
2011; Yihune and Bekele 2012; Datiko and Bekele 2014; Dinaw et al.
2017), and farmlands (Datiko et al. 2007; Gadisa and Hundera 2015;
Workineh and Reddy 2016). Only few studies were conducted outside
such areas (Habtamu and Bekele 2012; Admas and Yihune 2016).However, comparative studies conducted in Tanzania suggested a higher
diversity and abundance outside than in protected areas (Caro 2001,
2002). Thus, there are still many areas in Ethiopia yet to be explored
for species composition and distribution of small mammals (Habtamu and
Bekele 2008; Kassa and Bekele 2008).
Most rodents of Ethiopia are also geographically restricted to the
highlands (Yalden and Largen
1992). Many of these are potentially threatened because of their
extremely limited distributional ranges and habitat destruction (Fekdu
et al. 2015; Lavrenchenko and Bekele 2017). This may also hold true for
Wenchi highland, and open the door for faunal diversity, abundance and
distribution studies. In this highland, natural forests are fragmented
into numerous patches, and most of the medium to large-bodied mammals
are pushed out from the remaining forest fragments. Even primates that
have probably high level of tolerance to human disturbances (Bobo et al.
2014) are restricted except Colobus guereza .
Small mammals and birds may relatively persist in this modified habitat
(Shale et al. 2014), but the ecology of these animal groups in the area
is still poorly known. Thus, the purpose of the current study was to
explore the faunal diversity, abundance and distribution of rodents and
insectivores in Wenchi montane forests. Assessing this area for its
faunal diversity may, therefore, contribute to their conservation, and
enrichment of the faunal list of the country. Such studies could also
help in predicting the trends of faunal potential of the area and
document them before their extinction (Lavrenchenko and Bekele 2017).
Materials and Methods
Description of the
study area
The study was conducted in the central highlands of Ethiopia, Wenchi
district of southwest Shewa Zone, Oromia. It is located between Ambo and
Waliso towns, 155 km away from the capital, Addis Ababa (Fig 1). The
altitude of the area ranges between 2,810 and 3,386 m asl (Tefera et al.
2002). The area is characterized by highland sub-humid climate with the
average annual rainfall of 1400 to 1420 mm (Shale et al. 2014; Angessa
et al. 2020). It receives unimodal rainfall with longer rainy periods
stretching from May to September. The peak rainfall occurs in July and
August, while the cold-dry season occurs between October and January
(Angessa et al. 2020). The temperature varies between 14 to
26oC during the day and falls below
10oC at night (Degefu and Schargel 2015).