Topis (
Damaliscus korrigum) are a highly social
and fast antelope
species of the
genus '
Damaliscus.
[2]
The vernacular name "Topi" applies not only to the species but also to
two subspecies
D. k. jimela and
D. k. topi, while the name
Korrigum
or Tiang applies to the subspecies
D. k. korrigum.
[2]
Along with the
Bangweulu Tsessebe this species was formerly included in
the
Common Tsessebe. The species is to be found in the
savannas,
semi-deserts, and floodplains of
sub-Saharan Africa.
[edit] Description
Topi resemble
hartebeest but have a darker coloration and lack
sharply angled horns. They have elongated heads, a distinct hump at the
base of the neck, and reddish brown bodies with dark purple patchings on
their upper legs. They also have a facemask, a dark coloration on the
face. Their horns are ringed and lyrate shaped.
[3]
Their coats are short and glossy.
[4]
They range in mass from 75 to 160 kg and in height from 100 to 130 cm
at the shoulder. Males tend to be larger and darker than females. Topi
also have preorbital glands that secrete clear oil and hoof glands in
forefeet only.
[3]
When pressed they have been known to reach speeds in excess of 70 km/h
although they typically travel at a jog.
[edit] Subspecies
[edit] Range and ecology
The topi has an extensive geographical range with a patchy
distribution.
[3]
This is due to specialization for certain grasslands in arid and
savanna biomes.
[3]
Human hunting and habitat destruction have further isolated their
population.
[3]
The following countries have been found to contain Topi:
Benin,
Burkina
Faso,
Burundi,
Cameroon,
Central African Republic,
Chad,
Democratic Republic of the
Congo,
Ethiopia,
Gambia,
Ghana,
Guinea-Bissau,
Kenya,
Mali,
Mauritania,
Niger,
Nigeria,
Rwanda,
Senegal,
Somalia,
Sudan,
Tanzania,
Togo, and
Uganda.
The species is regionally
extinct in
Burundi,
Gambia,
Guinea-Bissau,
Mali,
Mauritania,
and
Senegal.
[5]
Topi primarily live in grassland habitats ranging from treeless
plains to light woodlands.
[3]
In
ecotone
habitats between woodlands and open grasslands, it largely inhabits the
edge using the shade in hot weather.
[3]
They prefer pastures with green grass that’s medium in length with
leaf-like swards. The densest populations can be found where green
pastures persist through the dry season, such as plains bordering lakes
and rivers with seasonal flooding.
[6]
With its short muzzle and mobile lips it harvests tender green blades
while avoiding mature leaves and stems.
[3]
When foraging, Topi tend to make small bites at a slow bite rate.
[7]
Topi generally frequent flat lowlands and are seldom found above 1500
m.
[3]
When they have access to enough green fodder, topi usually don’t have
to drink. They drink every day or two when subsisting on dry grass.
[8]
Topi commonly stand on
termite mounds or other vintage points and
survey the surrounding territories. Both adult males, females and young
use these vantage points.
[3]
This species tend to be either abundant or absent in an area.
[4]
Scattered populations don’t last long and either increase or die off.
[4]
When green grass is in inadequate, the condition of individual topi
decline and fail to breed. However they quickly recover when they gain
access to fresh fodder. They grow quickly and thus number recoup
rapidly.
[4]
Topi are also migratory and gather into herds of up to a few hundred
individuals to find their desired pastures, but the largest is in the
Serengeti
which they join the wildebeests, zebras and gazelles .
[9]
Topi migrate between the arid and savanna zones. Predators of topi
include
lions
and
spotted hyenas with jackals being predators of newborns.
Hyenas are the most common attackers.
[10]
Nevertheless, topi tend to have a low predation rate when other species
are around.
[3]
[edit]
Social
structure and reproduction
The topi’s social organization is perhaps the most variable of the
antelopes.
[11]
Depending on the habitat and ecological conditions, topi can be
perennially sedentary-dispersion, and perennially mobile-aggregated or
in-between.
[3]
In addition, the reproductive organization ranges from large
territories with resident female herds to small temporary territories in
aggregations to breeding on leks. Topi that inhabit patches of
grassland in woodland habitat are in the sedentary-dispersion mode.
[11]
Males establish territories that must contain enough resources to
sustain themselves and a herd of 2-6 females with their offspring
throughout the year. These territories can range as much as 4 km square
and, depending on the extent of the patches, may or may not have common
borders.
[3]
A female in the Serengeti may frequent a territory for three years.
[11]
The females in these territories function as part of the resident
male’s harem. These herds tend to be closed (expect when new females are
accepted) and both the males and his females depend the territory from
outside topi of either sex.
[12]
When the resident male is absent, the dominant female may behave like a
territorial male and approach both intruding females and males in the
rocking
canter and performing the
high-stepping display. This
mimicry appears to be to be convincing to other topi and sometimes even
humans.
[3]
Where topi live in relatively high population densities, like
Queen Elizabeth National Park
in Uganda, they circulate constantly and unpredictably across the plain,
and establish a temporary network whenever an aggregation settles down
for a few hours or days.
[3]
In areas such as
Akagera National Park in Rwanda and
Masai Mara
National Reserve in Kenya, topi males establish
leks which are territories that are clustered together.
[13]
These territories have little value outside of the males in them. The
most dominant males occupy the center of the lek cluster and the less
dominant occupy the periphery.
[14]
Males mark their territories with dung piles and stand on them in an
erect posture ready to fight any other male that tries to invade.
[9]
Estrous females enter the leks both singly and in groups and mate with
centrally located males.
[3]
For males living farther from the center, proximity of a territory to a
drainage line becomes more important in enhancing mating success.
[14]
Females will complete with each other for the dominant males
[15]
as females come into estrous for only one day of the year. Females
prefer to mate with dominant males that they have mated with before,
however males prefer to mate with females that they haven’t mated with
yet.
[15]
As such favored males prefer to balance mating investment equally
between females.
[15]
Females, however, will aggressively disrupt copulations that their
favored males have with other females.
[15]
Subordinate females have their copulations interrupted more often than
dominant females. Males will become more likely to counter-attack
aggressive females with whom they have already mated with in refusal to
mate with them any more.
[15]
The vast majority of births occur between October and December with
half of them occurring in October.
[16]
The calving strategy of the topi is intermediate between the "hider"
system (found in the
blesbok) and the "follower" system (found in the
blue wildebeest).
[3]
Calves can follow their mothers immediately after birth
[9]
and may not "lie out".
[3]
On the other hand, females separate themselves from the herd to calve
and calves commonly seek hiding places during the night especially when
not migrating.
[3]
The maternal bond between a mother and her calf ends after a year or
when she births and new calf. Both yearling males and females can be
found in bachelor herds.
[3]
[edit] Status and conservation
While the topi is still a numerous and widespread species. However,
it has been by hunting, and habitat degradation have eliminated it from
large areas of its former range.
[1]
The West African Korrigum has been hit most by this threats as they are
now extirpated from four of the 12 countries in which they formerly
occurred and they are likely only occur as vagrants in three.
[1]
Topi can be found in protected areas such as
Virunga National Park in the Democratic Republic of
the Congo,
Queen Elizabeth National Park
in Uganda,
Akagera National Park in Rwanda, The
Masai Mara in Kenya and
Serengeti National Park in Tanzania.
[1]
Tidak ada komentar:
Posting Komentar