Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 May 2023 | 15(5): 23200–23209
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.8297.15.5.23200-23209
#8297 | Received 02 December 2022 | Final
received 08 May 2023 | Finally accepted 15 May 2023
Current populations of Colobus vellerosus
(Geoffory, 1834) & Cercopithecus lowei (Thomas, 1923) and land-use, land cover changes
in Boabeng-Fiema Monkey Sanctuary, Ghana
Edward Debrah Wiafe 1, Karen
K. Akuoku 2, Isaac Sarkodie
3 & Maxwell Kwame Boakye 4
1 School of Natural and
Environmental Science, University of Environment and Sustainable Development,
P.M.B. Somanya, Ghana.
2 MONDAN Research
Institute, P.O. Box AP 255, Akropong-Akuapem, Ghana.
3 Boabeng-Fiema Monkey Sanctuary,
P.O. Box Nkoranza, Ghana.
4 Department of
Environmental Sciences, Ho Technical University, Ho, Ghana.
1 ewdebrah@uesd.edu.gh
(corresponding author), 2 karen.akuaku7@gmail.com, 3 isaacopokusaa@gmail.com,
4 mboakye@htu.edu.gh
Editor: Mewa Singh,
University of Mysore, Mysuru, India. Date
of publication: 26 May 2023 (online & print)
Citation: Wiafe, E.D., K.K. Akuoku, I. Sarkodie & M.K.
Boakye (2023).
Current populations of Colobus vellerosus (Geoffory, 1834) & Cercopithecus lowei
(Thomas, 1923) and land-use, land cover changes in Boabeng-Fiema
Monkey Sanctuary, Ghana. Journal of Threatened Taxa 15(5): 23200–23209. https://doi.org/10.11609/jott.8297.15.5.23200-23209
Copyright: © Wiafe et al. 2023. Creative Commons Attribution 4.0
International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: The study was funded by the University of Environment and Sustainable Development, Ghana.
Competing interests: The authors declare no competing interests.
Author details: Edward Debrah Wiafe is a
primatologist and conservation biologist as well as an Associate Professor in the School of Natural and Environmental Sciences, University of Environment and Sustainable Development. He is currently the Ag. Pro Vice-Chancellor of the same University. Karen K. Akuoku is the research officer at MONDAN Research Institute, an environmental NGO in Ghana. Isaac Sarkodie is the Secretary to Buabeng-Fiema Monkey Sanctuary Management Board, and a Tour Guide. Maxwell Kwame Boakye is a
Lecturer and Head of Department of Environmental Science, Ho Technical University, Ghana.
Author contributions: EDW—conceived the study concept, and participated collecting and analyzing the data, as well as writing and revising the manuscript. He also coordinated the submission and revision processes. KKA—involved in designing the study, conducting the research, and analyzing the data. She also assisted in writing and revising the manuscript. IS—provided technical expertise and, assisted with data collection, contributed to the study design and help revise the manuscript. MKB—supervised the field data collection, data cleaning and
analysis and provided guidance on the study design and execution. He also played a significant role in writing and revising the manuscript.
Acknowledgements: We thank the Management Committee of Boabeng_Fiema Monkey Sanctuary for permitting us access to
the Sanctuary. We also thank the community members who volunteered to assist us
in the data collection. We also thank th University
of Environment and Sustainable Development for sponsoring the study.
Abstract: Background and
Research aim: This study evaluated the density of two primate species Colobus
vellerosus and Cercopithecus lowei and the change in land-use types in Boabeng-Fiema Monkey Sanctuary in Ghana, from 2007 to
2019. Method: Total counts of individual
monkeys were done in all six patches of forest in the Sanctuary in 2019. Using
Landsat imagery, land-cover maps of the study area were examined to evaluate
the change that has occurred over a nine-year period between 2010 and 2019.
Results: A total of 602 individuals of C. vellerosus
were counted in 34 groups (0.58 group/ha). Group locations were: 15 at Boabeng (0.12 groups/ha), five at Fiema
(0.08 group/ha), three at Bomini (0.09 group/ha),
four at Busuyna (0.13 group/ha), three at Bonte (0.06 group/ha), and four at Akrudwa
(0.11 group/ha). C. lowei was only encountered
at Boabeng and Fiema, with
a total of 351 individuals distributed in 26 groups. In 2010, forest covered a
land area of 1,540.08 ha, and it was estimated to have increased to 2,643.12 ha
in 2019. Farmlands covered 5,069.07 ha in 2010, and in 2019 were estimated to
cover 4,155.03 ha. Built-up areas in 2010 covered an area of 433.89 ha, and in
2019 had declined to 244.89 ha.
Conclusion: The monkey populations have increased and spread to occupy
all patches in the Monkey Sanctuary. On LULCC, 72% increase, 18% reduction, and
44% reduction in forest cover, farmland and built-up areas were observed
respectively. Implications for conservation: There is a blend of traditional
and conventional conservation efforts contributing to the increase in primate
population, the occupancy of previously ‘empty’ forest patches and change in
areas of land-use types.
Keywords: Endangered species,
forest patches, human activities, indigenous knowledge, landscape, population
dynamics, primates, protected areas, satellite imagery.
Introduction
Human
population growth has had significant impact both directly and indirectly on
the dynamics and structure of biological communities. This is because of the
extension, growth, and dispersal of human populations, which have been greatly
influenced by both the agricultural and industrial revolutions. Nonhuman
primates are not exempt from problems associated with human population growth (Cowlishaw & Dunbar 2000). Early in the 1950s, it was
discovered that the Red Colobus Procolobus waldroni was imperiled due to habitat loss and
poaching, and Booth (1956) expressed the opinion that its extinction in the
Gold Coast (now Ghana) in the near future could be considered to be a
possibility. Booth therefore asked for effective laws that would safeguard the
species as well as its habitats, but it is now likely to be extinct (Oates et
al. 2000). Recent studies have clarified the realities that other related
primates have probably now been extirpated from most protected areas (Wiafe 2021) or a few groups occur where enforcement against
poaching has been intensified (Wiafe 2016).
In
addition, Oates et al. (2000) attributed the recent extinction of primates to
complacency, since primates in general have received much attention from
conservation measures and are regarded as one of the few large orders of
mammals not to have lost a taxon in the 20th century
(Mittermeier et al. 1997). Oates et al. (2000), however, warned that such
complacency may allow taxa that could have been saved by more vigorous and
timely action to become extinct. The danger could be particularly acute in the
case of taxa that have received little attention and live in parts of the world
where biologists and conservationists focus less. Also, reports indicate that
population trends for animals are more favorable in nations with higher
development rankings (Barnes et al. 2016).
Other
reports reveal that more than 50% of protected areas that contained Colobus vellerosus in the 1970s no longer contain it, and on
average an 87% reduction in encounter rates of this species in six forest
reserves in the last 30 years has been estimated (Matsuda-Goodwin et al. 2019).
This suggests an equivalent reduction in population size in recent times. On
the contrary, as of 2007, Boabeng-Fiema Monkey
Sanctuary (BFMS) in Ghana harbored 365 individuals C. vellerosus
(Kankam & Sicotte 2013)
and has consistently been a site for a stable population of this endangered
primate. Between 2007 and 2019 (about 12 years), no systematic census from the
sanctuary has been published, probably because the population appears to be
stable. However, the accelerated unwanted factors like deforestation,
over-exploitation of resources, invasive species, human population increase,
and weak legislation may have a great toll on the stable populations and
therefore a regular census is required (Ntiamoa-Baidu
1995; Attuquayefio & Fobil
2005).
Land-use
and land-cover change (LULCC) has been observed to be dynamic and accelerated
in recent times, influenced by factors such as farming, estate development and
mining, and aggravated by climate change impacts and adaptation. Bamford et al.
(2001) echoed that LULCC is a major driving force of habitat modification and
has important implications for the distribution of wildlife in ecosystems. The
need to regularly analyze LULCC cannot be over-emphasized, as it can be used to
predict changes in ecological systems and species population changes, as well
as examine the factors responsible for such changes. In the Masai
Mara ecosystem (Kenya), a 30-year LULCC indicated that a rapid land conversion
had a drastic decline on a wide range of wildlife species (Mundia
& Murayama 2009). In a study at BFMS in Ghana, Amankwa
et al. (2021) concluded from a 26-year LULCC analysis of six-year intervals
that the rapid changes were attributed to human population growth and
associated activities.
The
objectives of this study were to determine the species densities in the forest
patches; examine the population growth rate of the primates and determine the
relationship between the species densities and patch sizes. We also assessed
the change that has happened in land-use and land-cover over a decade.
METHODS
Study
Area
This
study took place at Boabeng-Fiema Monkey Sanctuary
(BFMS) which comprises forest patches in the villages of Boabeng
— 128 ha, Fiema — 62 ha, Bomini
— 30.6 ha, Bonte — 33.5 ha, Busuyna
— 54.1 ha, Akrudwa (Panin)
— 32.2 ha, Kwaase — 4.9 ha, Tankor
— 6.8 ha, Senya — 74.9 ha, and Akrudwa (Kuma) — 3.2
ha (Kankam & Sicotte
2013). BFMS is a community-based conservation area situated in the Bono-East
Region of Ghana located on with 7.666N to 7.669N and 1.629W to 1.700W. The 499.2 ha Sanctuary is
located in the Nkoranza North District on a flat
terrain. BFMS is a dry semi-deciduous forest which lies in the savanna
transition zone (Figure 1). The vegetation type is dominantly a primary mosaic
forest (Hall & Swaine 1981; Fargey 1991). BFMS
has two distinct seasons: rainy season between March and October and dry season
between November and February with the mean annual rainfall of 1,250 mm (Fargey 1991). The sanctuary is developed from the
traditional belief of the local people, where hunting and killing of a primate
is perceived as a taboo (Fargey 1991; Ntiamoa-Baidu 1995; Attuquayefio
& Fobil 2005). The sanctuary is noted as a
community-based conservation area with the community members in charge of
managing its activities. C. vellerosus and C.
lowei are the two primates in the sanctuary (Fargey 1991; Kankam 1997) with
over 3,700 human inhabitants (G.S.S. 2010). The community members cultivate
cashew, maize, yam, groundnut, cassava, and oil palm (Wiafe
& Arku 2012).
Study
species
Colobus
vellerosus White-thighed
Colobus and Cercopithecus lowei Lowe’s monkey
are two distinct primate species living sympatric in Boabeng-Fiema
Monkey Sanctuary (BFMS) (Kankam & Sicotte 2013).
Known
to be highly arboreal, C. vellerosus at BFMS
has been found to intermittently travel on the ground (Schubert 2011). The diet
has been observed to be mostly leaves, fruits, seeds, and flowers (Wong et al.
2006). This species has been reported in other protected areas in Ghana such as
Kakum National Park, Cape Three Points Forest
Reserve, Mole National Park, and Atewa Range Forest
Reserve (Wiafe 2016, 2019, 2021). It is also reported
to occur in Côte d’Ivoire’s Bandama-Sassandra
interfluvial zone (Gonedelé Bi et al. 2014), Togo’s Togodo Faunal Reserve, (Segniagbeto
et al. 2017), and Benin’s Lama and Kikele Forest
Reserves (Campbell et. al. 2008). It is currently classified as critically
endangered on the IUCN (International Union for Conservation of Nature) Red
List of Threatened Species (Matsuda-Goodwin et al. 2019) (Image 1).
C.
lowei is usually
found in primary, secondary, and gallery/riverine forest, and it is observed to
be active in the lower forest strata and on the ground (Wiafe
2016; Wiafe et al. 2019). The diet of C. lowei includes mainly fruits but is supplemented with
insects (Wiafe 2015). C. Lowei
are also distributed in some parts of Ghana including Kakum
Conservation Area, Cape Three Points, and Atewa Range
Forest reserves (Oates et al. 2000; Wiafe 2016,
2021), and Côte d’Ivoire’s Soko and Guelitapia forests (Gonedelé Bi
et al. 2014). It is currently classified as vulnerable on the IUCN red list of
species (Wiafe et al. 2019) (Image 2).
Survey design
The
study included the existing patches of forest stands where the management of
the sanctuary confirmed that those patches harbored monkeys for the past five
years. The management also informed us that forest patches of Akrudwa (Kuma) and Akrudwa (Panin) have been merged as Akrudwa.
Therefore, we surveyed in the following forests patches with respective sizes: Boabeng — 128 ha, Fiema — 62 ha, Bomin — 30.6 ha, Bonte — 33.5 ha,
Busuyna — 54.1 ha, and Akrudwa
— 37.4 ha (Figure 1). The vegetation type of the six patches has been described
by Kankam & Sicotte
(2013) as open forest mixed with savanna woodland. The already existing trails
(tourist trails) were used for the study, and only accessible paths were used
to assess the patches because the team decided not to disturb or destroy the
vegetation in the area by creating new paths. To equalize sampling intensity,
we used 17 transects of varying lengths ranging from 500─1,000 m to count
monkeys in all the patches of forests. In total, 71,050 m of transect walks
were made in specific patches as follows: Boabeng =
14,300 m, Fiema = 10,650 m, Bomini
= 11,200 m, Busunya = 12,450 m, Bonte
= 11,200 m, and Akrudwa = 11, 250 m.
Using
Landsat Imagery, a land-cover map of the study area was made to examine the
change that has occurred over a nine-year period between 2010 and 2019 (The
image with less cloud was obtained in 2010 instead of years around 2007).
Data Collection
Primate Species Enumeration
Six
selected patches were visited to identify and count the two sympatric primates
through visual observation of primate presence. Primate species censuses were
carried out within the six patches simultaneously by three people in one group
(18 people total). In each group, two members served as observers while one
member served as a recorder of the observations. Every team was led by a
Sanctuary staff member who was conversant with the territory of every primate
group. The team walked through the existing trails in the patches to search for
the primates with the help of binoculars used for scanning the canopy of the
vegetation. When primates were spotted, the species were identified and
counted, and the locations recorded. When a group of primates was spotted, GPS
coordinates were noted at the center of the group spread. The process started
at 06:00 GMT till they enumerated all the groups.
The
census was done two times to cross-check whether all the subjects were encountered.
To reduce observer bias, the start and end times of the census were clearly
stated to all team members, and team members were also reshuffled between
groups so that an area with species was not counted twice by the same group at
the second time. The numbers were estimated based on ‘good visibility’ counts
(Baker et. al. 2009).
Land-Cover Changes
To
verify how the land-cover has undergone changes and its possible effect on the
primate distribution, satellite images of the study area between 2010 and 2019
were analyzed. This study acquired a time frame series of two Satellite Landsat
Images: Landsat 7 ETM (Enhanced Thematic Mapper), representing the year 2010,
and Landsat 8 OLI (Operational Land Imager), representing the year 2019. These
two images were all acquired through the Google Earth Engine platform which
serves as a cloud-based system that houses several satellite images for earth
observation analysis. The image resolution was 30 m which was quite good for
image analysis. To select the best image, we considered images within the whole
year with least cloud cover. The chances were that the resolution of the images
from the dry season (December─March) was quite high,
so images from December 2010 and December 2019 were used.
Data
Analysis
Primate Density Calculations
The
number of groups and individuals were tallied and totaled for each transect and
patch.
The
line transect method has been widely used and is considered the most accurate
method of conducting wildlife surveys to study animal populations and calculate
species density (Whitesides et al. 1988; Plumptre 2000; Buckland et al. 2001), and the commonly used
software package DISTANCE has also been used for data analysis. However, the
use of this method requires certain criteria or assumptions in order for the
mathematical model to be applicable to the data (Buckland et al. 2001).
Unfortunately, several constraints prevented use of this method. First, most of
the time the monkeys detected the observer and started moving before the
observer could detect them. Second, there was poor visibility in the forest
which prevented the clear detection of the animals for accurate distance and
angle measurements as well as lesser number of sightings than 40.
As
the mathematical models associated with line transects model could not be
applied to calculate densities, primate density was calculated by the ratio of
number of group of monkeys or total individuals encountered to size of the
forest patch or length of transect (Collinson 1985; Ellis 2003; Wiafe 2016).
Statistical
analysis involved the use of ‘R’ statistical software version 4.2.1 (R Core
Team, 2021). The Shapiro-Wilk normality test was used to check the normality of
the abundances of C. vellerosus (response
variable), and the result indicated that the response variable was not normally
distributed (W = 0.68949, p <0.001). Therefore, Marasquilo’s
test was used to get an overall Chi square to compare medians of abundance of C.
vellerosus among all the six patches and pairwise
comparisons of the abundance of C. vellerosus
in any two different forest patches. The C. lowei
was encountered in only two nearby patches (Boabeng
and Fiema) and because of this we did not do any
further statistical analysis. The C. vellerosus
density change rate was calculated as follows:
Nt – No
Growth
rate = –––––––
No
Where:
Nt
= density at current time (2019)
No
= density at the beginning of the period (2007)
Since the time lag between the first and the second
densities was 12 years the population growth rate per annum was calculated by
dividing the growth rate by 12. For the C. lowei,
there was no known published previous population to serve as basis to determine
the change in population of the species, within the period.
Remote sensing analysis on
land-cover
We
preprocessed both images (Satellite Landsat images) in Google Earth Engine. The
preprocessing steps include the following: (1) filtering of the image by the
region of interest which was an extent of the area created as a feature; (2)
filtering by the date (‘2010-01-01’, ‘2010-12-31’) for 2010 and (‘2019-01-01’,
‘2019-12-31’) for 2019; and (3) filtering by least cloud cover and a median
composite of all the bands for the respective years.
A
supervised land-cover classification was then performed by first creating
training samples of the respective classes (forest, villages/communities, and
agricultural fields). The training samples were created with the help of
high-resolution images from Google Earth Imagery in comparison with other
literature studies on classification and knowledge of the study area. With the
training samples as inputs for the classification, we used a Classification and
Regression Tree (CART) classification algorithm which is a predictive model
that explains how outcome variables’ values can be predicted based on other
values in the Google Earth Engine that was used to classify the satellite
images into the land-cover classes listed above. This procedure was validated
as well with Google Earth Imagery again and other sources of literature (Allotey & Wiafe 2015) on
classification within the same study area. A change detection table was
generated where the area in terms of percentage and hectares of land-cover
between 2010 and 2019 was generated to assess the changes that took place over
time.
RESULTS
Population Densities of Primates
C. vellerosus
were encountered and distributed in all the six patches of forest at BFMS: Boabeng, Fiema, Bomini, Busuyna, Bonte, and Akrudwa. In all, a
total of 602 individuals were counted in 34 groups. These were made up of 15
groups of 315 individuals at Boabeng; five groups of
73 individuals at Fiema; three groups of 54
individuals at Bomini; four groups of 58 individuals
at Busuyna; three groups of 36 individuals at Bonte and four groups of 66 individuals at Akrudwa. In terms of density per patch size, Boabeng recorded 2.46 individual/ha, 1.18 individual/ha at Fiema, 1.59 individual/ha at Bomini,
1.87 individual/ha at Busunya, 0.67 individual/ha at Bonte, and 3.88 individual/ha at Akrudwa
(Table 1).
The
C. lowei were only encountered at Boabeng and Fiema, and in total,
351 individuals were distributed over 26 groups. In Boabeng,
18 groups were encountered with a total of 236 individuals, and eight groups of
115 individuals were encountered at Fiema (Table 2).
Further analysis indicated that
the densities of C. vellerosus encountered in Boabeng differ significantly from that of all the other
five patches (Fiema, Bomini,
Busunya, Bonte, Akrudwa). On the contrary, the densities of C. vellerosus in all other forest patches were found not
to be significantly different. (Marascuilo’s test:
Overall χ2=37.97 df-5 p<.001: For pairwise comparisons – BBG-FM χ2
= 12.59, df = 1, p<.02; BBG-BON χ2 =
30.91, df = 1, p <.01; BOS-BON χ2 =
12.14, df = 1, p <.03; BON-AKR χ2 =
11.83, df = 1, p <.03); Likewise, Marascuilo’s test for BBG-FM for C. vellerosus
χ2 = 0.001, df = 1, p <.98)
From the year 2007 to 2019 the
densities of the C. vellerosus in the entire
sanctuary increased by 70.0 % over 12 years at an average growth rate of 5.8%
per annum. There was, however, variation in the growth rate in different forest
patches as shown in Table 3.
Land-cover and Land-use Changes
The
classification approach yielded two land-cover maps within the area from
2010─2019 (Image 3). In 2010, forest covered a land area of 1,540.08 ha,
representing 21.87%, but the area was estimated to be 2,643.12 ha in 2019,
representing 37.53%. (Forested area has increased by 1,103.04 ha, representing
15.66%). Farmlands (agricultural lands) on the other hand covered 5069.07 ha
(71.97%) in 2010, but in 2019 these were estimated to cover 4155.03 ha (59.00%)
(a reduction of 914.04 ha or 12.97%). Villages or built-up areas in 2010
covered an area of 433.89 ha (6.16%), but 244.89 ha (3.48%) in 2019 (a
reduction of 189 ha or 2.68%) (Table 4).
DISCUSSION
The
conservation of primates in BFMS has solely depended on traditional knowledge
and belief until the early parts of 1970s when the government intervened to
support the management of the sanctuary. Since then, the sanctuary has been
combining the use of taboos and conventional law enforcement to prohibit
hunting of the primates in the sanctuary (Attuquayefio
& Fobil 2005; Saj et
al. 2005, 2006; Wong & Sicotte 2005; Kankam & Sicotte 2013).
Conservation education and other interventions such as eco-tourism, tree
planting, and eco-friendly agriculture have been intensified since 2010. It
could be deduced that within the six patches, C. vellerosus
and C. lowei were not evenly distributed. Both
were mostly concentrated at Boabeng and Fiema. This concentration could be attributed to historical
distribution, the traditional belief of not hunting or killing primates, and
the unsuitable nature of the other patches. The study area is a forest-savannah
transition zone; thus, the unsuitable nature of some patches is the result of
the limited number of trees, alongside the presence of some invasive species
such as Chromolaena odorata
(E.D. Wiafe, 2019 pers. obs. ) which suppresses the
growth of native plant species that might have been essential food sources for
the primates. Due to the savanna dominated nature of a patch such as Bonte of size 33.5 ha (Table 4), it is mostly shrub and
grassland with few trees. Thus, such an area becomes less attractive to the two
species.
It
was observed that C. lowei did not travel out
of the patches of Boabeng and Fiema
areas. This could be attributed to the fact that the local people of Boabeng and Fiema use human food
to feed C. lowei, as the people believe that
the primates are their ancestors (Wiafe & Arku 2012). This behavior of the people providing food for
the primates may have increased the availability of feed for C. lowei to limit them in Boabeng
and Fiema patches. The C. lowei
further forages on crops cultivated by humans which usually causes antagonistic
relationships. However, the people of Boabeng and Fiema have resolved to coexist and tolerate the destructive
activities of the monkeys to some extent as opposed to the people of other
patches. Notwithstanding, the C. lowei’s
absence in other patches is likely due to the natural dispersal pattern of the
species as (compared to C. vellerosus). In C.
vellerosus both sexes disperse, which makes it
very easy for new groups to form and spread (Teichroeb
et al. 2009, 2011), but in C. lowei, females
are philopatric (Cowlishaw & Dunbar 2000). This
means that new groups can only form by the fission of very large existing
groups and these new groups of females would all have to find their way to a
new fragment together. That is much more difficult and less likely than single
colobus making the journey, and making it far easier for new groups to be
created and to spread than for the female philopatric cercopethecines.
On
the other hand, C. vellerosus were found in
all the six patches, and this is not different from the report of previous
studies by Kankam (1997), Saj
et al. (2005), and Wong et al. (2006). In 2003, Wong and colleagues confirmed
the presence of C. vellerosus at Bonte and Akrudwa in addition to Boabeng, Fiema, Bomini and Akrudwa, just as Kankam’s report in 1997 and Kankam
& Sicotte (2013). It has been reported that Bonte has two groups of C. vellerosus
in the area with only one resident group (Kankam
& Sicotte 2013).
Over
the past decades, C. vellerosus population in
western Africa has experienced drastic decline resulting from habitat loss and
bush meat trade. Several studies (Fargey 1991; Kankam 1997; Wong & Sicotte
2005; Kankam & Sicotte
2013) at BFMS have shown that C. vellerosus
population has been increasing. As reported by Wong & Sicotte
(2005), this increment within the sanctuary can be related to the movement from
the small patches (within the study area) with less food resources available to
the larger patches which provide adequate resources for primates’ survival.
Comparing
the current census to the last census of 2007 (Kankam
& Sicotte 2013), the total number of groups of C.
vellerosus has increased from 29 to 34 (Table 1)
as follows: Boabeng has increased from 13 to 15; Fiema has reduced from six to five; Bomini
has increased from one to three; Bonte from two to
three; Busunya from three to four; and Akrudwa from two to four. Note that Kankam
& Sicotte (2013) reported one group at Konkrompe, but the sanctuary managers negated their current
presence. The average density in 2007 was 0.75 perha
and in the present study (2019) it was 1.28 per ha (Table 3). Comparative
analysis indicated that the population growth is 70% spread over 12 years at an
average growth rate of 5.9% per annum (though there were specific variations in
growth at the patch level) (Table 3). This comparison must be viewed with
caution since different surveyors and different data analysis methods were
used.
As
a community-based conservation area in the central Ghana, the people have
consciously made efforts to increase forest cover through planting of trees in
the villages, roadsides, and alongside agricultural crops in the farmlands.
Also, the decline in the cover of the villages (build-up) indicates that more
trees have been planted in the villages and that the people have promoted natural
regeneration of forests in previous opened areas. Comparing this study’s
results to the last land-cover analysis done in 2007, Allotey
& Wiafe (2015) reported that settlement expansion
due to the increasing human population in the area led to a 22.4% decline of
the forest cover. Meanwhile, agricultural land-use yielded a 54.5% increase in
land-cover, and build-up 23.1%. Tree harvesting has not been reported to have
caused a change in forest cover in the area. This is probable because primate
habitats are prohibited for human use in the sanctuary, but Amankwa
et al. (2021) recently reported charcoal and lumber production in the
surrounding areas. The results of this study showed increases in forest cover
by 71.62%, 18.03% reduction in farmland, and 43.56% reduction built up areas.
This improvement in forest cover creates better conditions for C. vellerosus groups to disperse to occupy all patches in
the nearby communities.
IMPLICATIONS
FOR CONSERVATION
BFMS
is the only conservation area harboring such endangered primates amidst human
activities such as agriculture and settlement expansion. Therefore, both
traditional and conventional knowledge have been necessary to put human
activities under control, which has allowed for the regeneration of the forest
cover in the study area. This creates a good impression about the forest cover,
hence a good condition for C. vellerosus group
dispersal to occupy all patches in the proximity. Also, the population of the C.
vellerosus has increased and more than doubled
within the 12-year period, showing that when species are protected against
hunting and habitat destruction, their population will increase (Wiafe 2016). The community members support the conservation
of the primates and protect their habitats to promote primate tourism, and as a
result contribute to the population stabilization and increase in the area of
distribution and occupancy. At present, habitat destruction, habitat
degradation, overexploitation, and poaching of wild animals, as well as climate
change have been identified as the major threats to wildlife in the world
(Hogue & Breon 2022). In that case, any efforts
to reduce the impacts must be embraced and supported.
The
results of this study do not conform to the totality of the notion that small
patches of habitat support smaller populations and if individuals are unable to
migrate to other suitable habitat areas, the population becomes isolated,
putting them at risk of extinction. However, with the institution of the
combination of traditional and conventional conservation intervention in highly
fragmented environments (as shown in this study), conserving parts of
acceptable primate habitats (forest patches) and prohibiting hunting have
allowed the primates to migrate between these different locations, occupy the
previous ‘empty’ patches as well as increased their populations. Existing
evidence suggests that some primate species, such as Chimpanzees Pan
troglodytes (McLennan 2008), Orangutans Pongo spp. (Spehar & Rayadin 2017), and Samango monkeys Cercopithecus albogularis
labiatus (Nowak et al. 2017), have extremely high
behavioral flexibility, allowing them to survive in human-modified landscapes.
Additional evidence is the forest patches in Belize’s Community Baboon
Sanctuary in which Steinberg (1999) found that a population of Black Howler
monkeys Alouatta pigra
increased by 138% over 13 years when forest buffer strips along property
boundaries and strips of forest across large cleared areas were maintained. As
a result, the population grew from 840 to over 2,000 individuals (138 %),
indicating that they have a high level of behavioral plasticity that allows
them to survive in human-modified environments.
We
therefore recommend that the government should prioritize the protection of the
sanctuary and channel resources to support the conservation of the two species
in the sanctuary. Regular population monitoring at short intervals should be
carried out by the Sanctuary Management Authority in collaboration with the
research institutions in order to predict the dynamics of population growth and
events that can affect the primates’ population. In addition, a land-use change
monitoring regime should be implemented in the area so as to invest resources
in the land-use type that favor both the human and non-human primates.
Table 1. Densities of
C. vellerosus enumerated in the forest patches
of BFMS (BBG—Boabeng | FM—Fiema
| BOM—Bomini | BUSU—Busunya
| BONTE—Bonte | AKRU—Akrudwa.
Forest patch |
Number of groups |
Number of animals |
Area (ha) |
Number of groups/ha |
Density/ ha |
BBG |
15 |
315 |
128 |
0.12 |
2.46 |
FM |
5 |
73 |
62 |
0.08 |
1.18 |
BOM |
3 |
54 |
34 |
0.09 |
1.59 |
BUSU |
4 |
58 |
31 |
0.13 |
1.87 |
BONTE |
3 |
36 |
54 |
0.06 |
0.67 |
AKRU |
4 |
66 |
37 |
0.11 |
1.78 |
Total |
34 |
602 |
346 |
0.09 |
1.74 |
Table 2. Densities of
C. lowei enumerated in the forest patches of
BFMS.
Forest patch |
Number of groups |
Number of animals |
Area (ha) |
Number of groups/ha |
Density/ ha |
BBG |
18 |
236 |
128 |
0.14 |
1.84 |
FM |
8 |
115 |
62 |
0.13 |
1.85 |
BOM |
0 |
0 |
34 |
0 |
0 |
BUSU |
0 |
0 |
31 |
0 |
0 |
BONTE |
0 |
0 |
54 |
0 |
0 |
AKRU |
0 |
0 |
37 |
0 |
0 |
Total |
26 |
351 |
346 |
0.07 |
1.01 |
|
26 |
351 |
190 |
0.14 |
1.84 |
For
figure & images – click here for full PDF
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