A Preliminary Survey of Medium-and Large-Sized Mammals and Their Conservation Status in the Asimba Forest Priority Area, Semiarid Highlands of Northern Ethiopia

. Mammal species provide vital environmental and economic functions although they globally face numerous threats. Knowledge of the composition and diversity of mammal species provide information for appropriate management interventions. We conducted this study from July 2019 to February 2020 to assess the species composition, diversity, and conservation of medium-and large-sized mammals in the Asimba Forest Priority Area, northern Ethiopia. Data were collected through direct and indirect evidence from three habitat types, namely, natural forest, bushland, and plantation forest. We analyzed the data using descriptive statistics and the Species Diversity Index. We also used χ 2 to compare diferences in the number of observations and species richness of the mammal species in diferent habitats between the dry and wet seasons. A total of 263 observations were compiled, and 15 medium-and large-sized mammalian species were recorded in the Asimba Forest Priority Area. Te Species Diversity Index and Evenness of the area were H ′ � 2.436 and J � 0.899, respectively. Hamadryas baboon ( Papio hamadryas ) was the most commonly observed species, with 20.7 and 19.2 relative frequencies in the dry and wet seasons, respectively, whereas striped polecat ( Ictonyx striatus ) was the rarest species, with 3.0 and 0.0 relative frequencies during the dry and wet seasons, respectively. Te number of observations ( χ 2 � 2.298, df � 2, and p � 0 . 316) and species richness ( χ 2 � 0.115, df � 2, and p � 0 . 943) did not difer signifcantly in the three habitats. Anthropogenic factors, mainly habitat destruction and overgrazing, were widely observed in the Asimba forest as conservation threats to the mammal species. Te current study helps to increase knowledge about the mammal species of the area and is essential for their future conservation strategies.


Introduction
Ethiopia is one of the world's richest biodiversity countries due to the altitudinal variations within the country that produce a range of climates that afect plant and animal distribution [1].Ethiopia has high mammal species diversity and endemism [2].It is believed that there are about 311 mammalian species in the country.Of these total mammal species, 55 are endemic [3].
Mammals in general and large-sized mammals (weighing >7 kg) and medium-sized mammals (weighing 2-7 kg) [4] in particular have ecological, economical, and recreational values [5].Te functional signifcance of mammal species lies in their ecological roles, including seed dispersal and predation on numerous plant species that change the structure and composition of the world's ecosystems [6,7].Medium-and large-sized mammals are key components of forest and savanna communities and are, therefore, considered good indicators of ecosystem health and integrity [4,8].Due to their regulatory roles as prey and predators, they infuence the community structure and complexity of the trophic levels in which they are involved [9,10].Terrestrial mammal communities are fundamental to the functioning of ecosystems, as they play a major role in nutrient cycling [11].Mammal species also provide important human benefts such as food, recreation, tourism, and income [12,13].However, this will become a reality only with the presence of documented information on the diversity, species composition, and relative abundance of mammal species.Even though mammal species provide ecological and economic functions, they face numerous threats globally, such as habitat loss, degradation, and harvesting (hunting and gathering for food, medicine, and materials) [4].Correspondingly, many mammal species in Ethiopia are threatened due to the ever-increasing human population, habitat loss, and degradation [14,15].As a result, many mammal populations around the globe have gone extinct and many others are declining [8].
Knowledge of the species composition and diversity of large-and medium-sized mammals in particular ecosystems is the frst step for conservation action, which provides information for the implementation of management plans [6], and is essential in preventing species extinctions [16].Hence, a number of studies have been carried out in diferent parts of the world related to the assessment of medium-and large-sized mammals in protected areas such as national parks, sanctuaries, and national priority forests [16][17][18][19].Similarly, several surveys were conducted focusing on the assessment of mammal species in diferent parts of Ethiopia [15,[20][21][22].Although medium-and large-sized mammal fauna represents one of the best-studied groups in the world, for many species, there are still knowledge gaps about distribution, habitat use, and persistence after habitat destruction in the Asimba Forest Priority Area [23].
Asimba Forest Priority Area is one of the oldest protected forests in Tigray National Regional State, northern Ethiopia and established as a national forest priority area in 2012.Six state forest priority areas are found in the region.Tese include Wujig-Mahgo-Waren, Hugumburda-Gratkahassu, Hirmi, Waldiba, Asimba, and Desea.Tus, the Asimba Forest Priority Area is one of the six state forest priority areas in the Tigray region [24].It has old biodiversity and a signifcant natural forest.It is believed that the natural forest also harbors high faunal diversity.However, Asimba forest has never been studied for its medium-and large-sized mammal species.Te aim of this study was, therefore, to provide baseline data on diversity, species composition, relative abundance of medium-and large-sized mammals, and anthropogenic impacts that are essential for conservation measures and building a management model of the mammal species.

Study Site.
Te Asimba Forest Priority Area is located in Tigray National Regional State, northern Ethiopia, particularly in Irob Woreda (Figure 1).It is located between 14 °26′45″ N and 39 °36′46″ E. Te study area is found in the semiarid eastern highlands of Tigray.Te forest is among the 58 national forest priority areas in Ethiopia.Te Asimba Forest Priority Area covers an area of about 5,000 hectares.Te forest is found in one of the seven Tabias (kebeles) of Irob Woreda, called Arae.Te study area accounts for 75% midland, 15% highland, and 10% lowland agroecological zones.Rainfall is marked by a weakly bimodal pattern, with small showers of rain during the months of March-May and a long rainy season in summer during the months of June-August.Te mean annual rainfall and mean annual temperature of the area are about 470 mm and 20 °C, respectively.

Preliminary Surveys.
A preliminary survey was done in June 2019 in order to have basic information on the forest.We also communicated with the Irob Woreda Natural Resource Conservation Ofce and the local communities to obtain information about the forest.Te vegetation structure and topography of the study area were observed and identifed.Accordingly, the study area was stratifed into three habitat types.Tese habitats include natural forests, bushland, and plantation forests.Te forest is dominated by plant species such as Juniperus procera, Olea europea, and Dodonea angustifolia.Furthermore, Combretum aculeatum, Carissa edulis, Calpurnia aurea, Acacia abyssinica, Maytenus obscura, and Acacia mellifera are plant species located in the Asimba Priority Forest Area.

Data Collection.
Data collection was conducted for 8 months, from July to October 2019 (the wet season) and from November 2019 to February 2020 (the dry season).We used direct sighting methods, indirect evidence, and interviews to collect the data.A combination of methods in a single study produces information at a faster rate and results in a more complete mammal survey than any single method [25].Te medium-and large-sized mammal species were surveyed using a diurnal line transect by walking at a constant speed following the work of Benchimol [8].Te diurnal line transect is a well-recognized and cost-efective methodology for surveying medium-and large-sized vertebrates [26][27][28][29][30].
Te survey of medium-and large-sized mammals was carried out on foot by walking along the transect lines [20] for 8 days per month.Te transect length was measured and located in the study area with the help of GPS.Te mammalian species were counted by surveying along the transect, following the direct sighting method [31].Te observed mammals were counted, GPS locations were recorded at each transect line, and species were identifed based on the Kingdon Field Guide to African Mammals [32], "Atibiwochu" [33], and Mammals of Eritrea and Ethiopia [34].Observation of medium-and large-sized mammals was done early in the morning during 06 : 00-08 : 00 hrs and late in the afternoon during 17 : 00-19 : 00 hrs, when most mammals were active.Te counting was done using binoculars and the naked eye, depending on the distance of the mammal species from the observers.A total of 40 (17 bushlands, 13 natural forests, and 10 plantations) randomly laid transect lines were established to count the observed mammal species.An average of 6 km was walked each day at a mean speed of 1 km/h.Each transect line was set at a distance of 0.5 km from other transects to avoid double counting.Upon a visual detection event, observers recorded the following: time, species name, and number of individuals.
We also walked along the established transect lines to document the composition and diversity of mammal species through indirect evidence.Indirect surveys, including fresh 2 International Journal of Ecology tracks, fecal drops, vocalization, and scratches, were used as they are very useful for recording when animals are naturally rare, nocturnal, cryptic, elusive, found at low densities, and difcult to capture repeatedly [35].
Treats to mammalian species that afect their distribution and abundance in the study area were observed and recorded during the transect walk.Questionnaire surveys were also conducted with communities living adjacent to the forest for many years and local administrative ofces to obtain information about the presence of medium-and large-sized mammals in the study area.A semistructured questionnaire was used to generate information on mammal presence, human-mammal interaction, and associated impacts [15,35].A total of 70 (47 male and 23 female) respondents living adjacent to the forest were interviewed.Interviews were mainly focused on the types of mammal species existing in the forest, human-wildlife conficts in the area, and the conservation status of the forest ecosystem.

Data Analysis.
We analyzed the data using descriptive statistics and the Species Diversity Index.Te mammalian species diversity of the study area was analyzed using the Shannon Diversity Index as follows: H′ � −PilnPi, where H′ � the Shannon Diversity Index, P i � a fraction of the entire population made up of species i, and ln � natural logarithm [36].Te species richness (S) of the mammalian species was calculated using the equation S � n, where n is the number of species in a community.Species evenness, which measures the pattern of distribution of the mammalian species present in the area, was evaluated using the Shannon-Wiener Evenness Index as follows: J � H ′ /H max , where J � Shannon-Wiener Evenness Index; H′ � Shannon-Wiener Diversity Index; H max � ln; and S � natural logarithm of the total number of species (S).Te Simpson Diversity Index of mammals in the current study area was calculated as follows: D � 1 −  (pi), where D � Simpson Diversity Index and P i � fraction of the entire population made up of species i. Te relative frequency (RF) was calculated by dividing the number of records for each species by the total number of records for all species.Chisquare (χ 2 ) was also used to compare diferences in the number of observations and species richness of the mediumand large-sized mammalian species in the three habitats.

Results
A total of 263 observations were conducted and 15 mammal species were identifed in the Asimba Priority Forest Area.Of these total recorded mammal species in the Asimba Priority Forest Area, 66.7% (n � 10) were observed from direct observations, while 33.3% (n � 5) were recorded from indirect evidence.Te identifed medium-and large-sized mammals were distributed in six orders and 11 families.International Journal of Ecology 3 Among the identifed orders, nine species were from the order Carnivora, two species were from order Primate, and the other four orders were represented by one species each (Table 1).Of the total mammal species recorded in the current study area, 73.3% (n � 11) of them were mediumsized mammals, while 26.7% (n � 4) of them were large-sized mammals.Te mammal species observed in the current study area were distributed in the natural forest, bushland, and plantation forest (Table 1).At the current study site, we recorded one species leopard (Panthera pardus) vulnerable to extinction.Even though the remaining mammal species (14) observed in the Asimba Priority Forest were listed as Least Concern in the IUCN Red List of Treatened Species, we observed that they were under threat as a result of anthropogenic factors such as habitat loss, killing, and humanwildlife conficts.
Out of the total observations recorded in the current study area, 62.4% (n � 164) were recorded during the dry season, while 37.6% (n � 99) were recorded during the wet season.Papio hamadryas had the highest frequency of 20.2% (n � 53), and Ictonyx striatus had the lowest frequency of 1.9% (n � 5) (Table 2).
Te respondents interviewed for the purpose of this study revealed that agricultural expansion towards the forest, cutting of trees for frewood and home construction, drought, and human-wildlife confict (as a result of crop raiding and livestock depredation) were the main threats to mammals in the current study area.According to the majority of the respondents, i.e., 62.9% (n � 44), habitat destruction is the main threat to medium-and large-sized mammals in Asimba forest.Of the total interviewees, 7.1% (n � 5) mentioned that drought is challenging for mammals found in the forest (Figure 2).Our feld observations also confrmed that human activities have greatly afected and disturbed the species composition and diversity of the mammals found in the Asimba forest.Te local people living in the vicinity of the Asimba forest were destroying trees for frewood and construction.Although Asimba forest is a protected area, it is subjected to grazing, resulting in biodiversity loss.

Discussion
In the current survey, a total of 15 medium-and large-sized mammal species were recorded in the Asimba Protected Forest in northern Ethiopia.Tis indicates that the study area could have a crucial role to play in the conservation of mammals, including vulnerable species.Te number of mammal species detected (i.e., 15) in the Asimba forest can be considered low when compared to the number of species recorded in the Municipality of Jaú, São Paulo, Brazil [37], Borena Sayint National Park, Ethiopia [20], Juchitan, Isthmus of Tehuantepec, Mexico [18], and Arawale National Reserve, Kenya [19].Fifteen medium-and large-sized mammal species were recorded in Lebu Natural Protected Forest, Ethiopia [22], and Wacha Protected Forest, Ethiopia [15], similar to the number of mammal species observed in Asimba forest.However, the number of mammals recorded in the Asimba forest was higher when compared with the number of species recorded in Mengaza communal forest, Ethiopia [38] (Table 4).
Te variation in the number of medium-and large-sized mammal species in the Asimba Priority Forest Area from mammal species recorded in another area might be due to environmental factors.Te distribution of species and biodiversity is determined by a large number of abiotic and biotic factors [40].Qufa and Bekele [22] pointed out that the variation might also be due to the diference in sample sites, sampling efort spent, season considered, and variation in vegetation physiognomy.Te reason for recording lower number of mammal species in the current study area may also be due to the impact of anthropogenic factors observed in and around the forest.Te presence of human activities around the habitat of mammals infuences the dispersal of the species [18,37].Te low number of small-and medium-sized mammals in the Asimba Priority Forest might also be related to climatic conditions.Climate change poses a long-term threat to mammal species.Mammal species severely afected by drought in diferent parts of the Tigray region.
Te highest mammal species diversity was recorded in bushland during the dry season, while the highest mammal species diversity was recorded in natural forests during the wet season.A survey of medium-and large-sized mammals in Lebu Natural Protected Forest, Ethiopia [22], and Wacha Protected Forest, Ethiopia [15], found the highest Shannon mammal species diversity in bushland, which is consistent with the current fnding.Te highest species richness in the Asimba forest was recorded in bushland and natural forest in the dry and wet seasons, respectively.Tis might be associated with a good source of quality food in these habitats.Te distribution of mammals in a given habitat may be associated with vegetation cover and food availability in the area.
Anthropogenic activities that negatively afect the species composition and diversity of medium-and large-sized mammals in the current study area were revealed at the study site.We confrmed the anthropogenic factors both through direct observations and interviews.Tese human activities in the present study absolutely had an impact on the habitat and resources of the wild mammals.Conservation challenges for the mammals in the Asimba forest were critical.Tis results in the loss of the territory and living range of medium-and large-sized mammals.According to [41], the population of large mammals is continuously 4 International Journal of Ecology declining in number due to the shrinkage of their natural habitats.Te presence of human activities threatens the existence of terrestrial mammals in any protected area [42].Human activities such as deforestation for agricultural expansion, charcoal production, fuel wood collection, and grazing by livestock resulted in the alteration of the natural forest [22], which is the habitat of mammal species.Reference [4] also noted that high anthropogenic pressure and human population growth are major drivers of biodiversity loss.Other studies also confrmed that human disturbances have serious negative consequences for populations of mammal species [18,39].International Journal of Ecology

Conclusion
Te current study identifed medium-and large-sized mammal species existing in the Asimba Protected Forest, which provides baseline information for future conservation and management plans for the species.Tis study is the frst ecological research ever carried out in the Asimba Protected Forest.A total of 15 medium-and large-sized mammal species were recorded in the forest.Human activities that afect the survival of the mammal species in the Asimba forest were also noted.Even though the numbers of medium-and large-sized mammal species recorded in the Asimba Priority Forest Area are considered low when compared with mammals recorded in other sites, this study, in conclusion, suggests that it will contribute to the management and conservation of mammal species in particular and protected areas in general.In relation to this, it can also be concluded that Asimba forest is one of the wildlife zones in northern Ethiopia.According to the fndings of this study, we suggest that urgent management and conservation practices for mammal species in particular and the natural ecosystem, in general, should be initiated through the active and positive participation of the local people in and around the Asimba Priority Forest Area.

Figure 1 :
Figure 1: Location map of the Asimba Forest Priority Area.

Figure 2 :
Figure 2: Responses of the respondents towards the threats of the medium-and large-sized mammals in the Asimba Forest Priority Area.

Table 3 :
Species diversity indices in dry and wet seasons during the survey period in the natural forest (NF), bushland (BL), and plantation forest (PL).

Table 1 :
List of mammal species, habitat types, and methods of detection in the Asimba forest.

Table 2 :
Mammal species recorded and their relative frequency observed during the survey period in Asimba forest.
Note.NR � number of records; RF � relative frequency; NRD � number of records in the dry season; RFD � relative frequency in the dry season; NRW � number of records in the wet season; and RFW � relative frequency in the wet season.

Table 4 :
Comparison of the number of medium-and large-sized mammal species recorded in the Asimba Priority Forest with mammals in other diferent study sites.