Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 June 2022 | 14(6): 21170–21178
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.5589.14.6.21170-21178
#5589 | Received 22 January 2021 | Final
received 14 May 2021 | Finally accepted 07 April 2022
Population and distribution of Wattled Crane Bugeranus
carunculatus, Gmelin,
1989 at lake Tana area, Ethiopia
Shimelis Aynalem
Zelelew 1 & George William Archibald
2
1 Bahir Dar University, College of
Agriculture and Environmental Sciences, School of Fisheries and Wildlife,
Department of Wildlife and Ecotourism Management, Bahir Dar, Ethiopia.
2 International Crane Foundation,
E11376 Shady Lane Rd, Baraboo, WI 53913, United States.
1 shimelisay@yahoo.co.in
(corresponding author), 2 george@savingcranes.org
Abstract: The Wattled
Crane is listed as Vulnerable on the IUCN Red List, and isolated population
occurs in Ethiopia. This study was conducted in Chimba
wetlands, Lake Tana area from October–2013 to December–2014. The objectives
were to understand the distribution and population status of the Wattled crane and assess the vegetation characteristics and
threats of the ecological units. The population size and density of cranes in
the study area was determined from weekly counts carried out in equal-sized
sampling units. The total survey area was divided into square grids, and each
of them was 1.23 square km wide/size. A total of 10 grid squares, which have an
area of 12.32 square km were considered for density analysis. Although the
total area of the study was 208.2 km2, unsuitable habitats, such as
forest or farmlands were excluded. Counts of cranes were made at known sites.
The density was calculated as the average number of cranes counted per unit
area. A total of 32 cranes were recorded. The density of cranes in the study
area is 2.6 per km2. Cranes were located in Addis Amba, Dehena Mesenta, Latamba, and Legdia local
administrative areas. The number recorded in each area varied, the largest (17)
was recorded in Latamba Kebele and the fewest (2) in Legdia. The dominant vegetation type of Chimba
wetlands is emergent macrophyte. However, the papyrus bed represents about 10%
of the wetland. Species of vegetation other than papyrus bed is represented by
a 20 quadrat study. A total of 26 macrophyte species belonging to 10 families
were recorded. Intensive cultivation, draining of the wetland, habitat
degradation, overgrazing of the wetland, overharvesting of papyrus, invasive
species, and over-flooding are the major threats of wetlands.
Keywords: Blue Nile, conservation, density,
ecological units, egg, habitat destruction, macrophytes, nesting site, threats,
wetlands.
Editor: Anonymity
requested. Date of publication:
26 June 2022 (online & print)
Citation: Zelelew,
S.A. & G.W. Archibald (2022). Population
and distribution of Wattled Crane Bugeranus
carunculatus, Gmelin,
1989 at lake Tana area, Ethiopia. Journal of Threatened Taxa 14(6): 21170–21178. https://doi.org/10.11609/jott.5589.14.6.21170-21178
Copyright: © Zelelew
& Archibald 2022. 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 project was funded
by International Crane Foundation (ICF), E11376 Shady Lane Rd, Baraboo, WI 53913, United States
of America.
Competing interests: The authors
declare no competing interests.
Author details: Shimelis Aynalem Zelelew (PhD), Associate Professor in ecological systematic zoology at Bahir Dar
University, College of Agriculture and Environmental Sciences, Department of
Wildlife and Ecotourism Management, Bahir Dar, Ethiopia. George
Archibald (PhD), senior expert and co-founder of the International Crane
Foundation, E11376 Shady Lane Rd, Baraboo, WI 53913, United States of America.
Author contributions: The authors have conducted the
project and collected data in the field at various times. Both authors have
participated in organizing and analyzing the data. The second author
participated in shaping and commenting the manuscript while the first author
write the draft paper.
Acknowledgements: This study was supported by the
International Crane Foundation. We would like to thank Karen Becker from ICF
for English editing.
INTRODUCTION
Cranes (family Gruidae) are among the world’s most threatened birds. Of
the six species occurring in Africa, Wattled Cranes
are listed as ‘Vulnerable’ on the IUCN Red List. Isolated populations occur in
Ethiopia and South Africa, which are not considered different subspecies (Beilfuss et al. 2007; BirdLife
International 2020). Wattled Cranes range across 11
countries from Ethiopia to South Africa, the majority occurring in the
extensive flood plain systems of southern Africa’s large river delta
(especially the Kafue, Okavango, and Zambezi). They are also found in smaller
wetlands throughout their range.
The status and distribution of
the Wattled Crane is of particular conservation
concern because of the species’ life history traits (e.g., delayed sexual
maturity and low reproductive output) and specialized habitat requirements (Johnsgard 1983). Wattled Cranes
are the most wetland-dependent of all Africa’s cranes (Meine
& Archibald 1996). When hydrological conditions are not satisfactory at a
particular location due to drought, flooding, or inappropriate water
management, most Wattled Cranes fail to initiate
nesting (Douthwaite 1974; Konrad 1981). The
availability of the Wattled Crane’s main food source,
underground tubers of spike rushes (Eleocharis
spp.), water lilies (Nymphaea spp.) and various sedge species
(especially Cyperus spp.), is also
negatively affected by disruption in the regular annual cycle of flooding and
drying (Beilfuss 2000).
Three populations of the Wattled Crane are recognized. The core population occurs in
southern central Africa on the primary floodplains and dambos
of the upper Congo, Zambezi, and Okavango river basins. More isolated
populations occur in Ethiopia and South Africa, with the Ethiopian population
likely to be a distinct subspecies (Jones 2003). However, this isolated
population presently is not considered as a separate subspecies (Beilfuss et al. 2007).
The total population of the species
was 13,000–15,000 in 1974–1994. However, it declined to 8,000 in 2004, with the
highest population residing in Zambia (4,500). The population and distribution
of Wattled Cranes in Ethiopia is poorly known. A
survey report in 2004 estimated less than 200 birds (Beilfuss
et al. 2007). However, a recent survey in 2017 suggested that a total of 366
were recorded because additional survey sites were added (Zelelew
et al. 2020).
The three species of cranes found
in Ethiopia; Wattled Crane, Eurasian Crane and the
Black Crowned Crane occur in different sites of the Lake area (Francis & Aynalem 2007; Aynalem et al.
2011). Wetlands of Chimba, Yiganda,
Gorgora and the Fogera wetland plain are the major
locations for the cranes. Past records show that the Wattled
Cranes occurred over a large range and different habitats in Ethiopia (Urban
& Walkinshaw 1967). However, recent studies showed that they are
distributed in the central, southern, and northwestern
parts of the country (Zelelew et al. 2020). Chimba wetlands are the breeding grounds of the Wattled Crane (Aynalem et al.
2011). Although these sites are known for breeding and foraging, total
population estimate of the species is still not known. Therefore, baseline
information on the distribution, population of the species, the vegetation
characteristics of the wetlands, and threats to the species can provide a
starting point for future monitoring, conservation planning, and developing
management intervention. Therefore, the objectives of this study were to determine
the distribution, population estimate, and assess the vegetation
characteristics of the wetlands, and the threats of ecological unit
conservation targets.
MATERIALS AND METHODS
Study area
The study was
conducted in the lake Tana area of Ethiopia. The southwestern part of the lake,
particularly the wetlands situated along the Gilgel Abay River, was the main focus of the study (Figure 1).
Lake Tana is the largest lake in Ethiopia, ca. 68 km wide and ca. 73 km long,
and is the source of the Blue Nile. About 83 wetland bird species have been
recorded here and their total population around Lake Tana is likely to exceed
100,000 individuals seasonally (Francis & Aynalem
2007).
Chimba wetlands are situated along the Gilgel Abay River. It is bounded
by 13 local administrative Kebeles (small districts that have at least 2,000
households), whereas the wetland itself covers four Kebeles: Latamba, Legdia, Addis Amba, Dehena, and Mesenta. Seasonal
flooding occurs during the rainy season, June–September. Conventional farming
is practiced in the area. Chimba wetlands harbor an enormous number of resident and migratory bird
populations. It is home to the largest Black Crowned Crane population of
Ethiopia next to the Gambela wetland flood plains (Zelelew et al. 2020). It is also the only place where
extensive papyrus beds remain in the Lake Tana area.
The study area is situated within
the temperate, cool sub-humid highland agro-ecological
zone (Sime & Solomon 2017). The elevation of Chimba
wetland area varies from 1,790–1,812 m.
The mean annual rainfall at Bahir Dar station is 1,439 mm. The rainfall
in the area has a unimodal peak extending from May–October followed by the dry
season from November–April. Ninety five percent of the annual rainfall occurs
during the wet season (May–October).
The geographical coordinates
where Wattled Crane occurs was recorded and mapped
using ArcGIS 9.3 Software to show where the species are concentrating. Single
species count method was employed. The typical feature of the habitat was
determined (Bibby et al. 1992; Sutherland 1996; Lloyd et al. 1998).
Distribution
and population
The
population size and density of cranes in Lake Tana area was assessed from 10
October 2013 to 30 December 2014. The study area was divided into 1.23 km
squares based on the size of the wetland and transferred to a GIS map during
field work. Weekly counts of cranes were made in 10 grid squares selected
systemically where cranes reside (Krebs 1978).
Search for cranes started from
0800 h up to 1800 h since the survey area was spread out and inaccessible.
Ground surveys were done by walking and a car was used to reach the study
areas.
Breeding pairs (territorial
pairs) and non-breeding ones (in this case family groups) were searched for by
a person walking along the edge of the wetland and stopping frequently to scan
using binoculars and spotting scope for birds. When nests were encountered the
distance from the observer and the approximate coordinates of the nests were
recorded by indicating the position relative to the grid map. Additional
information such as crane roosting site, foraging places, nesting sites and any
local movement of cranes from the local people was recorded while surveying the
birds.
The
population size and density of cranes in the study area was determined from
weekly counts carried out in equal-sized sampling units as described by Joly
(1969). These sampling units using x and y coordinates a ‘go to’
function in the GPS was practiced in the field to find the exact place. A total
sampled area of 12.32 km2 where cranes occur was considered.
However, the total area of the study was 208.2 km2. Areas that were
covered by unsuitable habitat, such as forest or farm land, were excluded.
Counts of cranes were made at known sites.
The
population density (R, birds/square km), was estimated using the following
equation,
R = ∑ y / ∑ z
where, y
is the number of birds in a quadrat and z is the area of the quadrat.
The population size (Y) for each survey period was calculated from the average
number of birds counted in each quadrat.
Vegetation
Macrophytes
were collected at each sampling site using one by one meter quadrat sampling
method. A total of 20 quadrats were collected. The quadrats were laid along a
diagonal line with an interval of 50 m. Papyrus were excluded for sampling
since the vegetation cover is distinct and known (10% cover). The collected
unknown specimens were identified to the species or genus level at the Addis
Ababa University Herbarium. The proportion of macrophyte cover per sampled area
was estimated.
Materials
Observations were carried out
with the aid of Nikon 12 x 25 © binoculars and 20–60x Swarovski Telescope. GPS eTrex® model 2004 was used to apply ‘Go to’
function, which was used to find the specified selected quadrat, and also to
limit the transect length. Grid map was used during the actual field work. Sony
‘16’ optical lens digital camera and Leica professional camera were utilized to
take pictures of the habitat components, features, and the macrophytes.
Threats
Threat types for each ecological
unit were listed out during field observation. Then each threat type was
evaluated based on their “severity” and “scope”, and their conservation
priority was also evaluated by “ranking” them as very high, high, medium and
low. The ecological units’ such as wetlands, indigenous trees, macrophytes,
shrubs and some wild animals’ were the conservation targets in the area. Their
conservation status of these ecological units were evaluated based on the
threat types that are listed out already.
And hence to indicate the degree of threat severity, a “severity” index
was assigned for each threat. A very
high level was given for the total eliminated ecological unit in the area, high
for seriously degraded, and medium for moderately degraded and low for slightly
impaired ecological components. Whereas,
for the “scope”, which shows the extent of damage of the area, spatially: very
high evaluation was given for 75% prevalence of the threat, high for 50–75 %
widespread threats, medium for the threats that are localized in limited spots,
and low for very localized spread. Based on this evaluation, a threat matrix
table was developed to provide priority of management action to conserve which
ecological unit.
Results
Distribution
and population
A total of 30 adults and two
juvenile Wattled Cranes were recorded in the sampled
area (Image 1). The density of Wattled Cranes in the
study area is 2.6/ km2.
Cranes were observed in four
Kebele’s areas (Legdia, Latamba,
Dehena Mesenta, and Addis
Amba). The number of Wattled Cranes recorded in each
Kebele was: Addis Amba, five; Legdia, two; Dehena Mesenta, eight; and Latamba, 17. All places are nesting sites for the species.
However, Latamba Kebele was a very important site for
Wattled Crane nesting sites because the nesting area
is larger than the others.
Lam Gebya,
Basha Dangela at Latamba Kebele, and Addis Amba area are nesting sites that
are far apart from each other. During the study period, two nests were
identified. The nesting sites were located where disturbance from people were
less. The average water depth where the nests are built was about 60 cm. The
nesting materials were mainly sedge plants cut from the surrounding area.
However, no chick was observed. But, for the first time, one egg that weighed
213.7 g was measured during October 2014.
Vegetation
characteristics
The dominant vegetation type of Chimba wetlands are the emergent macrophytes and papyrus
bed. A total of 26 macrophytes belonging to 10 families were recorded (Table
1). However, the major macrophytes were: Cyperus
rotundus, C. papyrus, Echinochloa
colona, E. stagnina, Hygrophila schulli, Ipomoea
aquatic, Leersia hexandra, Ludwigia stolonifera, Nymphaea nouchali,
Oryza longistamina, Perscaria
senegalensis, Potamogeton thunbergii,
and Sacciolepis africana.
The papyrus bed represents about
10% of the wetland area and is located around ‘Achifi
Gott’ and ‘Lamm Gebya’ in Latamba Kebele and Dhana Mesenta
area. The proportion of macrophytes other than papyrus was estimated in the
sample quadrat (Figure 2).
Ecological
unit conservation targets threats
The ecological unit conservation
targets were identified as: wetlands, riverine habitat, indigenous trees (like
fig trees, Sezigum gunensie,
Millettia ferruginea,
Mimousops kummel), macrophytes (like
some of them Cyprus papyrus), fishes, some primate species
(Grivet Monkey and Common Baboons), mammals (Water Buck), birds (like cranes,
water birds, passerine birds), and amphibians and reptiles (Table 2). The
threats that are potentially of harm to these ecological units are listed out
(Table 2).
As observed in the study area,
water is drained for Khat Catha edulis
cultivation (Image 2). Expansion of this activity has affected the wetland
ecosystem as the wetland dries fast before the next rain. The presence of a
large cattle population has also degraded the nesting sites of cranes. Bare
land is created around the wetland (Image 3). The flood also results in
sediment accumulation. This has affected Wattled
Crane feeding and nesting sites. Some wetland vegetation is being rooted out
due to intensive cultivation.
Seasonal flooding during the wet
season and water shortage during the dry season and self-removal of wet biomass
were observed. Overgrazing, wetland draining, habitat fragmentation, and
farming have affected the natural ecological process, which have impacts on
breeding and feeding sites of cranes. This creates competition for habitat,
reduction of breeding grounds leading to decrease in the viable population, and
ecosystem destruction. Encroachment of agriculture on wetlands and overgrazing
have affected the papyrus bed that is important for breeding and feeding sites
of birds, reptiles, amphibians, and fishes as well. Since the area is a
communal land, there is no proper management activity.
Discussion
The occurrence of 32 individuals
of Wattled Cranes showed that the population has
increased compared to 27 recorded in 2009 (Aynalem et
al. 2011). It could be even more since
inaccessibility and the limited position available to view the majority area of
the breeding wetlands could underestimate the number of breeding nests recorded
and also the number of juveniles. In addition to this factor, delayed sexual
maturity and low reproductive output and specialized habitat requirements could
account for low number of population (Johnsgard
1983). Particularly, when hydrological conditions are not satisfactory at a
particular location due to drought, flooding, or inappropriate water
management, most Wattled Cranes fail to initiate
nesting (Douthwaite 1974; Konrad 1981). The lack of
availability of the Wattled Crane’s main food source,
underground tubers of spike rushes (Eleocharis
spp.), water lilies (Nymphaea spp.), and various sedge species
(especially Cyperus spp.), also affects
the annual cycle of flooding and drying (Beilfuss
2000).
Wattled Cranes are distributed in the
extensive wetland areas of Legdia, Latamba, Dehena Mesenta and Addis Amba Kebele. The distribution of cranes and
the number of individuals/population is related to the presence of secure
habitats, nesting and feeding sites. Several of the Wattled
Cranes were located around their nesting sites because most cranes need
undisturbed nesting sites, except the Indian Sarus
Crane (Grus antigone), which is highly
tolerant of human activity. Wild cranes generally nest in isolated places where
the risk of predation is minimal (Archibald & Meine
1996; Claire et al. 1996; Bento et al. 2007; Sundra
2009); but studies carried out on nest success of Greater Sandhill Cranes at Malheur National Wildlife Refugia, Oregon showed that nest
concealment has no relationship with nest success (Ivey 2007). However, in the
breeding grounds of Wattled Crane at Lake Tana, nests
were built in secure and inaccessible places. This kind of behavior
accounted for fewer number of nesting sites at Chimba
area though there is more than 208 ha of papyrus bed. Similarly, the breeding
and nesting sites have been repeatedly used by the species since the beginning
of 2008 at Lake Tana area (Aynalem et al. 2011). This
indicates that Wattled Cranes are loyal to their
nesting sites. Unless they are disturbed, nesting site consistency has been
also reported by Bento et al. (2007) in the Marromeu
complex of the Zambezi Delta.
Papyrus swamp is an important
habitat supporting a wide diversity of species such as Sitatunga Antelope Tragelaphus spekei
and African Python Python sebae (Aynalem & Mengitu 2017); several birds with restricted distribution,
including the Papyrus Lesser Swamp Warbler Acrocephalus
glacilirostris at Chimba
wetlands. They provide breeding and feeding ground for numerous species of
fish, and also grazing of large herbivores (Aynalem
2017).
The two major threats to wetlands
in the area are habitat destruction through agricultural development and
over-exploitation (Aynalem 2017). This has affected Wattled Crane feeding and nesting sites. Some wetland
vegetation is being rooted out due to intensive cultivation, because private
lands are not clearly demarcated from communal ones.
Apart from major biodiversity and
ecological ecosystem services, a wide range of regulatory ecosystem services
are provided by Papyrus swamps. The services include water, carbon and nitrogen
cycles and buffering capacity for sediment and nutrient loads, as well as
services of benefit to communities, including biofuel, drinking water, building
materials, and flood control (Maltby 1986).
Seasonal flooding during the wet
season and water shortages during the dry season and self-removal of wet
biomass were observed. Overgrazing, wetland draining, habitat fragmentation,
and farming have affected the natural ecological process. These practices have
affected the breeding and feeding sites of cranes. This creates habitat
competition, reduction of breeding grounds leading to decrease in viable
population, and ecosystem destruction. Encroachment of agriculture on wetlands
and overgrazing have affected the papyrus bed that is important for breeding
and feeding sites of birds, reptiles, amphibians and fishes as well; this
phenomenon was described in developing countries (Dugan 1990). Since the area
is a communal land, there is no proper management activity.
Threats on the ecological setup
of wetlands arose from two major directions. First, from natural processes,
which could affect the normal functioning of natural processes derived from
natural forces such as seasonal flooding during the wet season and water
shortage during the dry season. This phenomenon is linked to the Inter Tropical
Convergent Zone (ITCZ) location of the area (Mohamed et al. 2005). The ITCZ is
characterized by a low-pressure zone at the meeting point between the dry northeasterly and moist southwesterly
winds, and is the major reason for a rainfall season in the area. Bahir Dar
annual rainfall records show there are pronounced periods of wetter and drier
fluctuations. The early period (1966–1977) was comparatively wet (average
1,661 mm), but this was followed by a dry period (1978–1987) with an
annual average of 1,239 mm. The driest year in the record was 1983, with
an annual rainfall of 895 mm. The wettest year was 1973, when the total
rainfall was 2,036 mm. The mean and median of the annual series rainfall were
1,439 mm and 1,468 mm, respectively. Seventy percent of the annual
rainfall was above 1,300 mm and 80% was above 1,200 mm. Self-removal of wet
biomass could also account as a threat. Overgrazing, wetland draining, habitat
fragmentation, and farming have also impacted the area. This phenomenon leads
to competition, reduction of breeding grounds, and then decrease of viable
population. In Chimba area, encroachment of
agriculture on wetlands and overgrazing are affecting the papyrus bed.
Wattled Cranes are flagship species
requiring extensive wetlands for feeding, breeding and resting. Chimba wetlands are the only areas that support these life
processes for this globally threatened species. Since the area is free grazing
land, community based sustainable utilization management must be implemented to
save this threatened species and other life forms as well.
Table 1. List of macrophytes in Chimba wetlands (Local status), Lake Tana area, 2014.
Family |
Species |
Growth habit |
Status |
Remark |
Acanthaceae |
Dyschoriste radicans Nees |
Herb |
LC |
Weed |
Dyschoriste sp. |
Herb |
LC |
Weed |
|
Hygrophila schulli (Hamilt.) MR. & S.M. Almeida |
Herb |
LC |
Weed |
|
Ceratophyllaceae |
Ceratophyllum demersum |
Submerged |
|
|
Convolvulaceae |
Ipomoea aquatic Forssk. |
Emergent |
LC |
Aquatic floater |
Cyperaceae |
Cyperus papyrus L. |
Aquatic |
LC |
Emergent |
Cyperus longus L. |
|
LC |
Emergent |
|
Cyperus macrostachyos |
Sedge |
LC |
Emergent |
|
Cyperus dives |
|
LC |
Emergent |
|
Cyperus rotundus |
|
|
|
|
Menyanthaceae |
Nymphoides indica (L.) O.Kunze |
Water herb |
|
Float leaves |
Nymphaea lotus |
Water herb |
|
Float leaves |
|
Nymphaea nouchali
var. caerulea |
Water herb |
|
Float leaves |
|
Onagraceae |
Ludwigia stolonifera (Guilt L. &
Perl’.) Raven |
Creeper |
|
Aquatic |
Ludwigia sp. |
|
|
|
|
Poaceae |
Hyperrhenia rufa Staps |
Grass |
LC |
Terrestrial |
Andropogon gayanus Kunth. |
Grass |
|
Terrestrial |
|
Snowdenia polystachya Pilg |
Grass |
|
|
|
Echinochloa colona (L.) Link |
Aqu.Grass |
|
Aquatic |
|
Echinochloa stagnina (Retz.) P. Beauv. |
Aqu.Grass |
|
Aquatic |
|
Leersia hexandra SW. |
Aquatic |
|
|
|
Sacciolepis africana CE. Hubb. & Snowden |
|
|
|
|
Oryza longistaminata A. Chev. & Roehr. |
Aquatic |
|
|
|
Eleusine africana |
Semi aquatic |
|
Edge part of wetland |
|
Phragmites australis.
(Cav.) Trin. ex Steud. |
Aquatic |
|
|
|
Pollygonaceae |
Persicaria senegalensis (Meisn.) Sojak |
Aquatic |
LC |
Creeper |
Potamogetonanceae |
Potamogeton thunbergii Cham. & Schlecht. |
Submerging |
|
|
Typhaceae |
Typha latifolia |
Aquatic |
|
|
Table 2. Ecological unit
conservation targets, threat. and ecological levels.
|
Ecological unit conservation
targets |
Threats |
Severity |
Scope |
Ranking |
Ecological level |
1 |
Wetlands and Gilgel Abay riverine habitat |
Habitat degradation |
High |
V. High |
V. High |
Ecosystem |
Draining of wetland |
Medium |
Low |
Low |
Ecosystem |
||
Over grazing |
Medium |
V. high |
V. high |
Ecosystem |
||
Cultivation and encroachment |
Medium |
High |
High |
Ecosystem |
||
Vegetation removal |
High |
Medium |
high |
Ecosystem |
||
Flooding |
High |
High |
High |
Ecosystem |
||
Invasive species |
Medium |
High |
Medium |
Ecosystem |
||
2 |
Indigenous trees macrophyte and
shrubs |
Deforestation |
High |
V. High |
V. High |
Community |
Overgrazing |
High |
V. High |
V. High |
Community |
||
Agriculture encroachment |
High |
V. High |
V. High |
Community |
||
Sedimentation |
High |
Medium |
High |
Community |
||
Invasive species |
Medium |
Medium |
Medium |
Community |
||
3 |
Fig trees, Sezigum
gunensie , Millettia
ferruginea, Mimousops
kummel , Cyprus papyrus |
Deforestation |
V. High |
V. High |
V. High |
Species |
Charcoal making |
Medium |
Medium |
Medium |
Species |
||
Construction |
Medium |
Low |
Low |
Species |
||
Lumber production |
Medium |
Low |
Low |
Species |
||
Burning (intentional) |
Low |
Low |
Low |
Species |
||
4 |
Fish |
Overfishing |
Medium |
Low |
Low |
Species |
Habitat loss |
High |
Low |
Medium |
Species |
||
Water Channelization |
Medium |
Low |
Low |
Species |
||
Wetland degradation |
High |
Medium |
Medium |
Species |
||
5 |
Primate species Grivet Monkey
and Common Baboons; Water Buck |
Habitat degradation |
V. High |
V. High |
V. High |
Species |
Killing (to remove them) |
Low |
Low |
Low |
Species |
||
Grazing competition |
Low |
Low |
Medium |
Species |
||
6 |
Birds (cranes, water birds,
passerine birds) |
Wetland degradation |
High |
V. High |
V. High |
Species |
Vegetation removal |
High |
High |
V. High |
Species |
||
Overgrazing |
High |
V. High |
V. High |
Species |
||
Breeding and feeding site loss |
High |
High |
V. High |
Species |
||
7 |
Amphibians and reptiles |
Wetland degradation |
V. High |
High |
High |
Species |
Killing (to remove them) |
High |
High |
High |
Species |
||
Food shortage |
V. High |
V. High |
V. High |
Species |
||
Breeding and feeding sites loss |
V. High |
V. High |
V. High |
Species |
||
Decreased water flow |
Medium |
Medium |
High |
Species |
For figures &
images - - click here for full PDF
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