2.4│ Methods of data collection
The standard field techniques including direct and indirect observations
were employed from July to December 2019 in FCF to collect data. The
survey was carried in the first two consecutive days every month and
twice a day (early in the morning during 06:00 to 08:00 hour and late in
the afternoon during 17:00 to 19:00 hour) following Legese et al.
(2019).
Direct and indirect observations for medium and large-sized mammals
surveys were started 200 meters inside from forest edge and were
recorded at the maximum of 100-meter distance from both the left and
right side during walking along the fixed-width transect line (Krebs,
2006).
Direct observation was made through binocular and naked eyes to assess
mammalian species and threats and indirect observation was made based on
indirect evidence of mammals such as carcass, footprint, holes, sound,
and fecal-pellet (Larsen, 2016; Laurindo et al., 2019).
During transect visits, a researcher and five trained field assistants
traversed the track lines. While the observer was walking quietly and
gently along each transects against the direction of the wind to
minimize disturbances of mammals, the data on any mammalian direct and
indirect observation such as species, size, and threats were trapped by
the camera and recorded on the datasheet. Body size, coloration,
presence, and absence of horn, horn shape, genitalia, and dominant
behavior were used to identify observed mammals following the Kingdom
Field Guide to African Mammals (Kingdom, 2003).
2.5│ Data analysis
All the observed (direct or indirect) mammals were identified to their
respective orders, families and species level by using the taxonomic
characters listed in Kingdom (2003), and Yalden and Largen (1992). The
relative abundance of each species was computed using the percentage,
from total number of each species observed per total individuals
observed in the area.
Both qualitative and quantitative data were analyzed with descriptive
statistics. SPSS Version 16.0 statistical program, PAST version 3.26b
Statistical Package (Software) and appropriate statistical methods such
as mean and percentage were used. Gini Simpson and Shannon-Wiener
Diversity Index were computed by using PAST. A chi-square test was used
to compare the seasonal variation in species abundance at 0.05 levels of
significance. The threats were analyzed systematically by condensing and
summarizing information.
3│RESULTS
3.1│ Mammalian taxonomic
composition
A total of twenty-one mammalian species belong to six orders and
thirteen families were identified by direct and indirect field evidence
in FCF. The species richness varied across orders and families. Order
Carnivora represented by the largest number of families (five) followed
by Artiodactyla (three) and Rodentia (two). Tubulidentata, Primates, and
Lagomorpha each represented by single-family. Order Artiodactyla
composes 33% of total species followed by Order Carnivora composes 29%
of total species (Figure 3). More mammalian species were recorded for
the family Bovidae (four species), followed by Cercopithecidae (three
species). The families Suidae, Felidae and Sciuridae were represented by
two species each. The remaining seven families Hippopotamidae,
Orycteropodidae, Hystricidae, Hyeaniadae, Mustelidae, Viverridae,
Canidae, Leporidae were represented by single species (Table 1).
Among identified mammals eleven (52.4%) species were large-sized and
ten (47.6%) species were medium-sized (Table 1). Eight of the recorded
mammal species observed using indirect evidence (Table 1) whereas the
remaining thirteen records of observation for mammal species were
through direct sighting (Table 1). Out of a total of 21 species
recorded, 20 species occurred during wet and dry seasons. Panthera
pardus recorded only in the wet season.
3.2│ Abundance of mammals
A total of 685 medium and large-sized mammalian individuals belong to
six orders, thirteen families and twenty-one species were identified in
FCF. The number of individuals varied among orders and families (Figure
3) and among species (Figure 4). The abundant order by the number of
observations from the study area was recorded by order Primates which
include 284 individuals followed by order Artiodactyla include 201
individuals. The least abundant order was Tubulidentata which composes
only 8 individuals. The most abundant family was Cercopithecidae (284
individuals) whereas the least was Viverridae comprises only two
individuals. Among mammals, Chlorocebus aethiops (19.27%) andPapio anubis (19.27%) were the most abundant mammalian species
in the study area followed by Phacochoerus aethiopicus (7.74%).Panthera pardus and Civettictis civetta each contributed
only 0.29% of the total recorded individuals.
The abundance of mammals varied
between seasons (Table 2). 371 (54.16%) individuals were recorded in
dry season while 314 (45.84%) individuals were recorded in wet seasons.
The variation of mammals between seasons was statistically significant
(𝜒2 = 40.783; df = 20; 𝑃 < 0.05). The relative abundance of
the different mammalian species varied from 0.32 to 20.38% in the wet
season and from 0.27 to 21.56 % in the dry season. Two speciesPapio anubis , and Chlorocebus aethiops were relatively the
most abundant in both seasons (Table 2). These two species contributed
36.94% and 39.89% of the total sample of the wet and dry season
survey, respectively. The remaining mammalian species of individuals
contributed between 0.23 and 8.28% in the wet season and 0.27 and
7.28% during the dry season survey. Mammals of individuals ofPontamochoreus larvatus, Papio anubis and Chlorocebus
aethiops showed significant variation between wet and dry seasons and
the other species significant level did not reveal variation between
seasons.
3.3│ Diversity indices of
mammals
The overall species richness of
FCF was 21 and Shannon–Wiener Index values (H) was 2.56 and Simpson’s
index of diversity showed the highest species diversity (0.8968) in the
study area (Table 3).
3.4│ Threats to mammals in
the study area
Human and non-human activities have threatened mammals and their
habitats in the study area. During the present study periods, the major
threats observed in the area were hunting, logging, deforestation,
predation, invasive alien plants, overgrazing, and mining.
Hunting : The high rate of
incidence of hunting was recorded for Papio anubis because its
extent of damage was high to the local community and agricultural crops.Chlorocebus aethiops was also a pest on crops resulting in
hunting. Xerus rutilus was hunted by young men also recorded in
the area. During the fieldwork, the researcher had counted 8 carcasses
of mammals of Phacochoerus aethiopicus, Chlorocebus
aethiops , Panthera pardus, and Papio anubis .
Predation : Papio anubis killed and eat the young ofRedunca redunca was recorded. Predation by dogs of animals likeCivettictis civetta and Orycteropus afer were recorded.
Overgrazing : Locals
regularly bring cattle to the forest mainly for drinking water in the
Lake Abaya. Mammals Cattle overgrazing and competition for food
resources were recorded. Even though cattle are prohibited, they cause
severe overgrazing around the edge of the forest.
Deforestation :
Deforestation for agricultural land expansion was observed at the edges
of the forest. Clearing forest by humans from adjacent croplands to
avoid large mammal pests was also recorded. Papio anubis damage
to the natural forest through debarking and destroying the young and
seedling plants was also recorded.
Logging : During the
transect walk evidence of illegal logging such as the removal of trees
for timber production, for fuelwood and construction materials and grass
collection for cattle and thatching houses were observed.
Invasive alien species :
The encountered invasive alien species during the transect survey were
water hyacinth Parthenium weed (Parthenium hysterophorus ) and
Lantana weed (Lantana camara ) at the edges of forests and roads.
The invasive plant Parthenium weed (Parthenium hysterophorus )
dominated the place at some edges of the forest and homogenized the
place (see Appendix 3). Also, they reduced the grass species abundance
for herbivores mammals.
Mining : Mining of stone
for cobblestone by different enterprises in different parts of the
forest was another challenge observed during the survey, and severely
affecting forest habitat of mammals.
4│ DISCUSSION
4.1│ Mammals composition
and abundance
The present survey revealed
different large and medium-sized mammals from FCF and a total of 21
species were identified from 685 total observational records. These
mammal species were grouped into six orders and thirteen families. Some
studies that have used similar transect line techniques and to areas of
different protection levels across the country and elsewhere revealed
that the medium and large-sized mammals recorded were lower than the
result obtained from the present study. For example, Geleta and Bekele
(2016) recorded 15 mammal species in Wacha Protected Forest, Western
Ethiopia by direct and indirect evidence. Also, Woldegeorgis and Wube
(2012) recorded 14 mammal species from Yayu forest in southwest
Ethiopia; Atnafu and Yihune (2018) recorded even lower (12) mammal
species in the Mengaza communal forest, East Gojjam, Ethiopia. This
variation might account for variation in mammals’ group composition,
variation in vegetation structure and human influence and livestock
grazing.
The number of medium and large-sized mammals recorded during the present
study was comparable to several other studies conducted in Ethiopia and
elsewhere. For instance, Njoroge et al. (2009) recorded 23 species in
Arawale National Reserve, Kenya; Bene et al. (2013) recorded 23 species
in Sime Darby, Liberia; Girma et al. (2012b) recorded 19 species in
Wendo Genet, Ethiopia; and Ofori et al. (2012) recorded 23 species in
the moist semi-deciduous forest of Ghana. The relative abundance of food
sources, dense green vegetation cover, and high survey period, good
management practice of local people and availability of water (Lake
Abaya) were might be the major factors governing their abundance and
species richness in the present study area.
Some studies conducted in different countries revealed that the medium
and large-sized mammals recorded were higher than the result obtained
from the present study. Some of the studies among others include
Cortes‐Marcial et al. (2014) recorded 35 mammals in Oaxaca, Mexico and
Melo et al. (2015) recorded 33 mammals in northern Amazon, Brazil. This
might account for variation in sample sites, season considered, and
variation in vegetation cover.
Most mammals were recorded by direct observations during the present
survey. This result disagreed with the result obtained by Alves et al.
(2014) in which out of a total of 239 individuals 75% were obtained
from indirect evidence, footprints but agrees with most studies in
different localities (e.g. Legese et al., 2019; Gonfa et al., 2015)
The orders and families of mammals recorded in the present study were
higher than with the study conducted on medium and large-sized mammal’s
indifferent localities. For instance, Legese et al. (2019) identified
five orders and seven families in Wabe forest, Ethiopia. Also Qufa and
Bekele (2019) identified seven orders and 11 families from Lebu Natural
Protected Forest, Southwest Showa, Ethiopia; Laurindo et al. (2019)
found out six orders and 12 families, Cerrado remnants in south eastern
Brazil; herein FCF 6 orders and 13 families were recorded.
The Primates were the most abundant orders recorded and all belongs to a
family Cercopithecidae. Pabio anubis and Chlorocebus
aethiops were the most abundant mammal species in the study area.
Similarly, several studies have also reported a higher relative
abundance of Primates than other orders from different parts of Ethiopia
(e.g. Geleta and Bekele, 2016; Gonfa et al., 2015; Girma et al., 2012b).
This is could be due to the high reproductive successes, their more
adaptive nature to different habitats, diversified foraging behavior and
high tolerance level of Primates to human disturbances (Negeri et al.,
2015).
The abundance of carnivores was minimal; however, it contained the
highest number of family (4) among other orders. Among the recorded
carnivores, Civettictis civetta, Panthera leo and Panthera
pardus were least abundant. This might be associated with a minimal
number of herbivores and their nocturnal behavior. As described by
Hunter and Yonzon (1993), most carnivore species are solitary, nocturnal
and crepuscular so that their presence could not be easily documented.
Order Artiodactyla has the highest species richness and the second
abundant order recorded. Phacochoerus aethiopicus was abundant
and Ourebia ourebi was the least abundant species recorded in
this order. The destruction of habitat is especially harmful to large
mammals that require large home ranges to fulfill their nutritional
requirement (Ripple et al., 2016).
Orders such as Rodentia, Tubulidentata, and Lagomorpha were recorded as
less in the number of individuals. This inline with other studies in
different localities in Ethiopia (e.g. Atnafu and Yihune, 2018; Geleta
and Bekele, 2016; Gonfa et al., 2015).
The number of individuals of mammals recorded during the dry season
(371) surpassed the number of recorded during the wet season (314). This
inline with the work of Kasso and Bekele (2017) in Assela fragmented
forest, Ethiopia. The possible explanation for this could be the high
number of people and livestock were encroaching more during the wet
season than the dry season. Growth of herbaceous and ground vegetation
might have provided thick cover for the mammals, which makes the
sighting of them difficult (Gundogdu, 2011).
The species index of the diversity of the study area showed higher
species richness (H = 2.56; 1-D = 0.8968) than to study conducted
by Qufa and Bekele, (2019) in Lebu natural protected forest, Ethiopia (H
= 2.119; 1-D = 0.8167). Different possible factors contributed might be
due to higher survey period and availability of food sources, dense
forest cover, and water.