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Virunga Volcanoes Range Mountain Gorilla
Jean Uwilingiyimana Boston University Department of Geography & Environment GE 307: Biogeography
2011
1 Uwilingiyimana / Biogeography (Spring 2011)
I. Introduction
We are often all too concerned with the consequence of civil war conflicts on human
populations so much so that we tend to give little to no attention to the effects that such
conflicts have on plant and animal species. The civil war conflicts that have raged the
Eastern-African countries of Uganda, Democratic Republic of the Congo, and Rwanda are
primarily examples that have an a devastating impact on human populations as well as
animal populations. Gorillas in general are listed as one of the top 10 threatened or
endangered species, with only 655 species remaining. As far as the mountain gorilla is
concerned however, there are approximately 355 in the Volcano and Virunga Mountains of
Rwanda and Congo and another separate group of 300 in Uganda’s Bwindi Impenetrable
Forest.
The uniqueness of these three nations is that they’re the only places were mountain
gorillas reside, no gorillas live outside their native mountain forest homes. It is important
to look at all three of these countries in trying to understand the effect of civil conflict on
gorillas. Primarily because the civil conflict in each country features its own unique
circumstances, characteristics and impact levels. One certain shared characteristic of all
three however is the destruction of habitat that only is home to the mountain gorillas but is
also a food resource necessarily for the species survival. In many ways, the effects that civil
conflicts have had on people in those areas of the world are very similar to the effects on
gorillas. Decades of civil conflict in the region have affected the livelihoods of local peoples
and in turn have caused significant population displacements and enormous refugee
settlements and situations that have all had a large impact on the natural environment and
formerly protected area that is home to mountain gorillas. Though there has been great
effort put towards restoring their habitats and protecting them from poaching and
diseases, mountain gorillas, earth’s largest primates are still very much endangered and
decades civil conflicts in East Africa have played a great role in doing so, primarily due to
habitat destruction.
The purpose of this paper and project is to examine the civil conflicts and the level to which
they have contributed to the destruction and disturbance of natural habitats and
ecosystems that are related to the survival of the gorilla species. Furthermore, to examine
2 Uwilingiyimana / Biogeography (Spring 2011)
further the relationship between the decrease in the number of mountain gorillas relative
to the escalation of civil conflicts in the region, how small or large of a factor it plays.
II. Virunga Volcanoes Range (VVR)
Geography
The Virunga Volcanoes Range that covers the DRC, Uganda and Rwanda is comprised of
three separate parks: The Mikeno Sector of the Virunga National Park (Parc National de
Virungas) in the DRC, the Volcanoes National Park (Parc National de Volcans) in Rwanda,
and the Mgahinga Gorilla National Park, as shown in Figure 1. The Range is located
between 25o and 35o latitude south and 29o and 30o longitude east.
Figure 1. Virunga National Park and Virunga Volcanoes Range (VVR)
The VVR covers an area of approximately 450km2 and
ranges in altitudes between 1,850 meters and 4, 507
meters above sea level. The VVR is an area of afro-
montane forest of high biodiversity importance within
the Albertine Rift; this is in part due to the mountain
gorilla as well as other endemic flora and fauna found
in the volcano range (Plumptre et al., 2003).
Approximately, eight different categories of vegetation communities have been identified in
Volcano Elevation(ft) Elevation(m)
Mikeno 14,557 4,437
Karisimbi 14,787 4,507
Visoke 12,175 3,711
Muside 9,843 3,000
Sabinyo 11,923 3,634
Mgahinga 11,398 3,474
Muhavura 13,540 4,127
VirungaVolcanoes
Table 1. Volcano names and elevation
3 Uwilingiyimana / Biogeography (Spring 2011)
the VVR according to McNeilage 1995. Due to vast range in elevation of the VVR, vegetation
zones are distributed according to altitude, ranging from mixed forest at lower altitudes, to
bamboo and higher altitude forest types to alpine vegetation and bare rock at the highest
altitudes, where you increasingly approach the tops of the volcanoes, as shown in Figure 2.
Due to the nature of the volcanoes that are present in the range, there is a battle to access
in regards to vegetation and habitats that are suitable for gorillas. Unfortunately, these
same places are also the ones that are at accessible and arable altitudes for human
populations that fled into the forests during times of conflict.
Figure 2. 2003 Virunga Landsat TM Classification
The bare rock that is observed at the periphery of the VVR is result lava from the
volcanoes; it goes without saying of course that the majority of the existing vegetation in
the VVR is atop of what used to be lava as well. Also, as supported by the Landsat image in
Figure 2, the majority of the mixed forest is at higher altitudes around and rising up the
volcanoes. This only leaves the herbaceous, hagenia, and bamboo vegetation available to
inhabiting species, particularly gorillas that prefer lower vegetation and rarely frequent
4 Uwilingiyimana / Biogeography (Spring 2011)
any areas above 3,3500m [Fossey, 1974; Harcourt & Curry-Lindahl, 1979; Watts, 1984;
McNeilage, 2001].
The climate of the VVR is similar to that of any Albertine Rift montane forest, that is to say
tropical and subtropical moist broadleaf forests. These forests normally provide trees that
are very good for fuel wood, which is very popular in that region of Africa, particularly in
refugee settlements.
Background and History
During the time of the civil conflicts in the East African region, similar conflicts and wars
seemed to be increasingly globally as the United Nations identified 28 such complex
emergencies ongoing in 1995 alone. One common character of many civil conflicts and
wars is that they are fought or tend to occur around border areas. Dating far back in
history, international boarders have always been drawn along natural divisions, such as
mountain ranges, rivers, and lakes [Lanjouw 2000]. The Virunga Volcanoes Range itself
was in such a predicament.
A closer look at Figure 3
shows the National Park
looked at the intersection
of borders of the
Democratic Republic of the
Congo, Uganda, and
Rwanda. Each of these
nations has had civil
conflicts for at least four
decades, internally or
externally amongst each
other.
Formerly known as Albert National Park, Virunga National Park was created in 1925,
making it Africa’s first official national park. The United Nations Education, Scientific, and
Cultural Organization (UNESCO) declared it a World Heritage Site in 1979. Fifteen years
later during the ongoing civil and ethnic conflicts in Rwanda and the Congo, UNESCO
Figure 3. Virunga Volcanoes National Park
5 Uwilingiyimana / Biogeography (Spring 2011)
declared the National Park as a World Heritage Site in danger. The park is known for its
exceptional diversity, containing more bird, mammal and reptile species than any
protected area on the African continent. As the Congo, Rwanda, and Uganda gained
independence, they each took on the task of managing the park area within their own
territories. This decreased the original cover 8090km2 of the park by half. The park later
became the base for the American naturalist Dian Fossey to carry out her research into the
gorillas, where She arrived in 1967 and set up the Karisoke Research Centre between
Karisimbi and Visoke. She would go on to spend most of her time in the park, and is widely
credited for saving the gorillas from extinction by bringing their plight to the attention of
the international community [Briggs and Booth 2001].
While the civil conflicts in all three countries has been ongoing for a breadth of time, the
Virunga Volcanoes National Park really saw its worst time beginning in 1992, where it
became it a battlefield during the Rwanda Civil War and then later on the war been Rwanda
and the Democratic Republic of the Congo. The majority of damage in relation to the Park
cover in Uganda can be accredited to the refugee crisis that arose from ethnic conflict in
Rwanda in the 1970s during which the Tutsi were expelled from power and from the
country all-together. The Tutsi would spend their “diaspora” primarily in the part of the
park held in Uganda, otherwise known as the Mgahinga Gorilla National Park; from here
the Tutsi would mount a rebel opposition that would attempt to retake power beginning in
1990.
III. The Mountain Gorilla
Biology
Since they were brought to light to the international community by
Dian Fossey beginning in 1967, mountain gorillas have received a lot
of attention in regards to keeping the species from going extinct. The
IUCN Red Data Book places the mountain gorilla, gorilla beringei
beringei, as a distinct subspecies of the eastern gorilla species as well
as the eastern lowland gorilla, gorilla beringei graueri, found in the
Bwindi Impenetrable Forest in Uganda.
Figure 4. Male Silverback
6 Uwilingiyimana / Biogeography (Spring 2011)
Mountain gorillas are in general much larger physically than other subspecies of the gorilla
species and have longer hair. The average adult male weights 350 lbs. while the average
female weights 215 lbs. They inhabit montane forests as well as bamboo forests at altitudes
ranging between 2,000 and 4, 000 m (8,200 – 13, 100 ft.). Their diet is composed of leaves,
shoots and stems of herbaceous vegetation; nearly 86% of their diet is vegetarian.
Mountain gorillas eat 142 different plant species along with three types of fruit.
In terms of social structure, mountain gorillas live in stable groups or habituated with a
dominant male and several females, though 36% of gorilla groups have more than one
adult male. Remaining gorillas are either lone males or
exclusively male groups. Emphasis is placed on protecting
groups versus territory. Around 12 to 15 years of age, adult
males develop a silver spray of hair across their backs, hence
the term silverbacks [Fig. 4]. Gorillas live to between 40 and
50 years of age and females generally first give birth amongst
the ages of 10 and 12, with a 9 month gestation period as
humans do, and inter-birth internals of 3-5 years. Females
have a reproductive cycle of approximately 28 days of which
they are fertile only 1 to 3 days. Most males and about 60% of females leave their natal
group and emigrate to other groups. Males normally leave at 11 years of age and travel
alone for 2 to 5 years before they can attract a group of females to form a new habituated
group. Whereas females normally leave their natal group around 8 years old and transfer
to an already habituated group.
Like humans, gorillas are diurnal and mainly terrestrial. The dominant silverback male
determines the movements of the group and group cohesion tends to be attributed to the
desire of group members to remain close to the silverback male for protection.
Population
Estimating the mountain gorilla population has presented its challenges particularly
because researchers and park authorities were unable to collect population data during the
years of serious conflict in the DRC as well as Rwanda.
Category Age
Infant 0-3.5
Juvenile 3.5-6
Subadult 6-8
Blackback 8-12
Adultfemale 8-death
Silverback 12-death
AgeCategories
Table 2. Age Categories used for
classification
7 Uwilingiyimana / Biogeography (Spring 2011)
In 1959-1960, researcher George Schaller estimated a population between 400 and 500
individuals in the Virunga Mountains. This estimation however was strictly based on group
sin the VVR around Kabara Meadow in Virunga National Park in the DRC and the Ugandan
area of the VVR.
The next detailed census was carried out between 1971-1973, in which the mountain
gorilla population was estimated to be between 260 and 290 individuals [Harcourt &
Groom 1972; Groom, 1973]. Three years later, 1976-1978, another census revealed that
the gorilla population continued to decrease, now between 253 and 285 individuals
[Weber & Vedder, 1983]. Again, in 1981, another census showed a continued gradual
decline in absolute population size [Aveling & Harcourt, 1984] estimating the population to
now range from 242 and 266 individuals. Vedder and Aveling conducted reported new
estimates in 1986, which showed an increase in total population size, 252 and 285
individuals. Another census three years later in 1989 continued to show increasing
population, placing the population now at 324 individuals [Sholley, 1991]. Then there was
the 2000 census that estimated between 359 and 395 individuals [Kalpers et al, 2003]. This
census however was based on knowledge about regularly monitored groups and
information gathered during ranger patrols, so it’s accuracy was never established. The
population size dynamics from 1959 to most recently 2003 are shown in shown below [Fig.
5].
Realistically, it was impossible to undertake a census between 1989 and 2003 due to
extreme insecurity in the region and it was generally perceived that gorillas had died
amongst the violence. The estimates from 2000 however, which were based decent
information and previous knowledge showed otherwise. The most recent census that was
carried out in 2003 revealed that there is currently 380 individuals. Further breakdown
reveals 16 habituated groups consisting of 269 individuals, 12 unhabituated groups
consisting of 80 individuals, and 11 lone silverbacks. The population size reveals a 17%
increase since 1989 and annual growth rate of 1.15%. While this growth rate is much less
than that seen during the 1980s, it is miraculous that the growth rate managed to remain
positive between 1989 and 2003 considering the extremity and longevity of the violence
that has taken place in the DRC, Rwanda and Uganda from 1989 to 2003.
8 Uwilingiyimana / Biogeography (Spring 2011)
Figure 5. High and Low Population Estimates [Data collected from the ICCN 2003 VVR Census Report]
Distribution
As mentioned before, mountain gorillas normally prefer altitudes of low vegetation. The
17% increase that was observed in population appears to be concentrated almost entirely
in one section of the range, south of Visoke and the flanks of Mount Karisimbi in Rwanda. In
the past, the vast majority of groups were found at the heart of the VVR, at Mount Visoke,
and the valley between Mount Visoke and Mount Sabyinyo.
Gorilla distribution across the VVR varies due to several factors. In the DRC for example,
the decline in the Mikeno area population was due to direct poaching during the Zairian
civil war in the mi 1960s [Webber & Vedder, 1983] whereas in Rwanda it is attributed to
large-scale habitat loss [Harcourt & Fossey, 1981]. Furthermore, it is important to note
that the Ugandan area of the VVR has an inadequate supply of food for the mountain
gorillas so the population in that region is transient. In some cases also, there will be many
groups of gorillas with few individuals in them, or a few groups comprised of a larger
number of individuals.
0
100
200
300
400
500
600
Go
rill
a P
op
ula
tio
n
Years
VVR Population Estimates [1959-2003]
Population (Low)
Population (High)
9 Uwilingiyimana / Biogeography (Spring 2011)
Figure 6. Gorilla distribution across VVR 2003
Figure 7. Gorilla distribution across VVR 2010
10 Uwilingiyimana / Biogeography (Spring 2011)
Distribution shown in Fig. 7 is according to data collected between 2008 and 2009. Over
the last several years, Rwanda has had the best economic and political climate compared to
the DRC and Uganda; consequently the conservation efforts in the Volcanoes National Park
of Rwanda have had a much more measurable impact, as seen by the number of habituated
gorilla groups in the Rwanda part of the VVR. However, even though the number of groups
increased, the size of these groups in general decreased. Even so, the increase is enormous
when you compare the gorilla groups’ census map of 2003 [Fig. 6] versus that of 2010 [Fig.
7]. Even with increased numbers and groups due to conservation however, the distribution
in the VVR overall appears to have the same pattern.
IV. Threats to the Gorilla Population and Challenges to Conservation
Habitat Loss and Destruction
The Virunga volcanoes region has high human population densities with an average of 300
people per square kilometer and 820 people per square kilometer in some rural areas
[Waller, 1996]. Some 90% of these people rely on subsistence farming for a livelihood and
depend on resources such as fuel wood for heating and cooking as well. In addition to the
poor communities that were naturally taking advantage of the habitat of the VVR, during
the civil war conflicts in the DRC and Rwanda, the VVR was a passing ground as well as
hiding and refugee area for people fleeing war. The physical location of the range, amidst
the international borders of three countries whose armed conflicts were related in one
fashion or another, the mountain gorilla population was not only vulnerable to the direct
violence that occurred to its habitat but also now had to deal with increased competition of
the same resources and land that the subspecies relies on for survival.
Poaching
The threat of poaching comes in two varieties, direct and indirect. Direct poaching is the
active and intentional capturing and killing of mountain gorillas, as a source of witchcraft in
in the early 1970s, then for hands and heads as trophies as well as selling infants to zoos in
the mid and late 1970s. The selling of infants to zoos inevitably involves the killing of adult
gorillas, particularly males because of their defensive behaviors and protection of their
groups, especially their infants. Indirect poaching occurs when gorillas get caught in the
cross fire and traps targeted towards other animals in their habitats, such as buffalo,
11 Uwilingiyimana / Biogeography (Spring 2011)
bushbuck, and duiker (Plumptre et al., 1997; Mudakikwa et al., 2001). This threat affects
the infant and juvenile age-sex categories.
Civil Conflict and Decades of War
While habitat loss and destruction and poaching can be perceived as issues in their own
context, the civil conflict that has taken place in the great lakes region, which contains the
DRC, Rwanda, and Uganda, can solely be blamed for all the threats and challenges to
preserving the mountain gorilla in the Virunga volcanoes mountain range. During civil and
armed conflicts, intentional strategies designed to cause famine and/or disease or divert
access to food supplies from one group to another, are often implemented as a tactic of war.
This tactic is not only detrimental to the natural environment; it in many cases causes
hunger issues which result further destruction of the environment and natural habitats.
The civil conflicts along the borders between the DRC, Rwanda, and Uganda that have been
ongoing for decades are still unresolved. Militias roam in the Virunga forests of the DRC
and other rebel units based in the DRC often attack Rwanda and Uganda. Within the DRC
there are clashes amongst different groups that continue to destabilize the country and
displace more and more of the DRC population. There also exists a conflict between the
Rwandan- and Ugandan-backed rebels in the eastern DRC where the VVR is located.
Currently, seven African nations along with a multitude of rebel groups are militarily
engaged in the DRC. As one can imagine, all these conflicts have had and still are having a
crucial impact on the wildlife, biodiversity and national parks of the involved countries.
The threats to the mountain gorilla that is home to this natural habitat and environment
include:
Destruction of social structures and institutions, as well as a legal framework, which
makes it virtually impossible to set any guidelines or laws about anything, including
protection of gorillas
Increased dependence on natural resources for food, building supplies, firewood,
and charcoal; creating competition of resources amongst inhabiting people and
gorillas
Presence of armed combat, landmines, and booby traps in forests and protected
areas home to mountain gorillas.
12 Uwilingiyimana / Biogeography (Spring 2011)
Clearing of gorilla habitats by armed factions for security tactics
Mass settlements of displaced refugees in natural areas and protected areas which
limits space for the gorillas and exposes the mountain gorillas to human diseases
Illegal harvest of natural resources and poaching of protected wildlife due to
absence of law which lead to the killing of 18 mountain gorillas between 1995 and
1998
These are just some of the threats that the civil conflicts in the DRC, Rwanda, and Uganda
has brought about. Going forward, these conflicts must be addressed if the preservation of
the mountain gorillas is to be successful.
V. Population Viability Analysis
The social behavior of the mountain gorilla by nature makes it virtually impossible to have
a meaningful population viability analysis even though the Virunga gorillas have been
studied for about three generations now. For starters, approximately eight adult females
die per year, which is equivalent to 10% of the total number of females in a population.
Even though the population is heavily monitored, this number is too close to sampling
error especially considering the fact that nearly 60% of all females emigrate and
disappearance technically doesn’t indicate death.
Mace and Lande’s (1991) suggested a set of criteria that can be used to determine the
imminence of extinction of a species. These are: (1) Population numbers must be less than
250 individuals; (2) the population has suffered a decline in numbers greater than 20%
over past two years or 50% over a generation; (3) the population is subject to crashes
greater than 50% reduction every five to ten years; (4) the population is fragmented,
meaning less than three subpopulations of more than 125 individuals with immigration
rates of less than one per generation.
For the Virunga gorilla population, which I considered as three separate subpopulations
(one in the DRC park, the other in the Rwandan section of the range, and lastly the Ugandan
section of the mountain range), the three criteria mentioned above are met but it is
virtually impossible to determine the last. For the last criteria, rapid censuses are needed,
13 Uwilingiyimana / Biogeography (Spring 2011)
which unfortunately has been impossible due to civil war and conflict in all three countries
for nearly the last twenty years and more in some cases.
Looking at internal stochastic events, the mountain gorilla population reached its lowest
size at 254 individuals, at which point 60% of adults could potentially breed, of which only
half of the adult males were in breeding groups. In the long run this produces an effective
population of 70 to 100 individuals, which is extremely concerning. However the fact that
gorillas tend to live for long years eases the concern. With a generation time of least 20
years, Soule’s (1980) estimates about 1000 years until the Virunga gorillas reach an
extinction threshold. Similarly, other studies (Durant and Mace 1994; Akcakaya and
Ginzburg), point to a 10% probability of the Virunga mountain gorilla going extinct within
the next 500-750 years, assuming no migration and no external deterministic effects such
as human interference.
External influences on the other hand paint a completely different picture regardless of the
lack of data. The mountain gorilla primarily dwells in the forests and the forest loss and
destruction rates in Africa strongly correlate to the increasing rates of human population
density in and around the natural habitats of mountain gorillas. Forest eradication rates are
obtained using rates of population increase and the relation between human density and
rate of forest destruction. For example, using the rates of forest eradication at four times
the current human population density as measure of intensity of threat as suggested by
Harcourt 1995, the Virunga mountain gorilla population goes extinct in under 100 years.
This is assuming the forests of the DRC that house the majority of the mountain gorillas
completely are destroyed. Aside from the DRC, only three other African countries have
forests capable of lasting 150-200 years, by which point the gorilla population would be
either extinct or very close to being extinct.
VI. Conclusion
It is quite evident that the mountain gorilla (Gorilla beringei beringei) population is
currently at low numbers and under many pressures. The population viability analysis
clearly shows that with stochastic events alone, the mountain gorilla population can grow
to reach a stable population size. It has also shown however, that external deterministic
effects on the gorilla population can lead to a very quick extinction of the population.
14 Uwilingiyimana / Biogeography (Spring 2011)
In large part, the mountain gorilla population is heavily reliant on its forest dwelling for
survival and any compromising and/or destruction of that habitat consequently have a
large impact on the viability of the gorilla population. The one critical thing that the
population viability analysis shows is the critical important of the mountain gorilla habitat.
In addition to the destruction of the forests due to human settlement and civil conflict,
increased human population density has caused competition of natural resources and
increased gorilla exposure to fatal diseases.
If the mountain gorilla preservation is to survive extinction there are two major steps that
need to be taken. First and foremost, the civil conflicts that have raged the DRC, Rwanda,
and Uganda for decades have to be resolved because for as long as they continue there will
be no legal framework for which gorillas can continue to be protected. Fortunately, as of
2005 the region has been getting more and more stable and observed numbers of gorillas
continue to increase since 2003. Secondly, the national governments of all the DRC,
Rwanda, and Uganda have to implement land use policies that direct human settlements
away from mountain gorilla habitats. It’s goes unsaid that obviously the second step is
impossible without rule of law and I fear that as long as the civil conflicts are not fully
resolved, the mountain gorilla will always be at risk in the Virunga Volcanoes Range.
15 Uwilingiyimana / Biogeography (Spring 2011)
Works Cited
Biswas, A.K., H.C. Tortajada-Quiroz., V. Lutete, and G. Lemba. “Environmental Impact of the Rwandese refugee
presence in north and south Kivu.” United Nations Development Programme. 1994
Gray, M., McNeilage, A., Fawcet, K., Robbins, M.M., Ssebide, B., Mbula, D. & Uwingeli, P. “Virunga Volcanoes Range Mountain Gorilla Census 2003.” Joint Organizers’ Report 2005. UWA/ORTPN/ICCN.
Aveling, C. & Harcourt, A.H. (1984) A census of the Virunga gorillas. Oryx, 18, 8-13. Butynski, T.M., Werikhe, S.E. & Kalina, J. (1990) Status, distribution and conservation of the mountain gorilla in the
gorilla game reserve, Uganda. Primate Conservation, 11, 31-41 Fossey, D. (1974) Observations on the Home Range of One Group of Mountain Gorillas (Gorilla gorilla beringei).
Animal Behaviour, 22(3), 568-581. Harcourt, A.H. & Groom, A.F. (1972) Gorilla census. Oryx, 11, 355-363 . Harcourt, A H. (1978). “Strategies of emigration and transfer by female primates, with special reference to
mountain gorillas.” Zeitschrift fur Tierpsychologie, 48, 401-20. Harcourt, A.H. & Curry-Lindahl, K. (1979) “Conservation of the Mountain Gorilla and its habitat in Rwanda.”
Environmental Conservation, 6, 143-147. Harcourt, A.H. & Fossey, D. (1981) “The Virunga gorillas: decline of an 'island' population.” African Journal of
Ecology, 19, 83-97. Harcourt, A.H., Fossey, D. & Sabater Pi, J. (1981) Demography of Gorilla gorilla. Journal of Zoology, 195, 215-233. Harcourt, A.H., Kineman, J., Campbell, G., Yamagiwa, J., Redmond, I., Aveling, C. & Condiotti, M. (1983)
Conservation and the Virunga gorilla population. African Journal of Ecology, 21, 139-142. Harcourt, A H (1986) “Gorilla conservation: anatomy of a campaign. In Primates. The Road to Self-Sustaining
Populations”. K. Benirschke, ed. Pp. 31-46. New York: Springer-Verlag. IUCN (2000) Red list of threatened species. Species Survival Commission, IUCN-The World Conservation Union,
Gland, Switzerland. Kalpers, J. (1992) La conservation du gorille de montagne. Le point de la situation en 1993. Cahiers d’Ethologie, 12
(4), 467-490. Kalpers, J., Williamson, E.A., Robbins, M.M., McNeilage, A., Nzamurambaho, A., Lola, N. & Mugiri, G. (2003).
“Gorillas in the crossfire: population dynamics of the Virunga mountain gorillas over the past three decades.” Oryx, 37, 326-337.
Lanjouw A., Kayitare A., Rainer H., Rutagarama E., Sivha M., Asuma S. & Kalpers J. (2001) Beyond Boundaries:
Transboundary Natural Resource Management for Mountain Gorillas in the Virunga-Bwindi Region. Biodiversity Support Program, Washington, D.C., U.S.A.
McNeilage, A. (1995) Mountain gorillas in the Virunga Volcanoes: ecology and carrying capacity. PhD dissertation. School of Biological Sciences, University of Bristol, Bristol, UK.
Miller, P., Babaasa, D., Gerald-Steklis, N., Robbins, M.M., Ryder, O.A. & Steklis, D. (1998) Population biology and
simulation modeling working group report. In: Can the Mountain Gorilla Survive? Population and Habitat Viability Assessment for Gorilla gorilla beringei (eds S. Werikhe, L. Macfie, N. Rosen & P. Miller), pp. 71-105. IUCN/SSC Conservation Breeding Specialist Group, Apple Valley, Minnesota.
16 Uwilingiyimana / Biogeography (Spring 2011)
Mudakikwa, A.B., Cranfield, M.R., Sleeman, J.M. & Eilenberger, U. (2001) Clinical medicine, preventative health
care and research on mountain gorillas in the Virunga Volcanoes region. In Mountain Gorilla: Three Decades of Research at Karisoke (eds M.M. Robbins, P. Sicotte & K.J. Stewart), pp. 342-360. Cambridge University Press, Cambridge, UK.
Plumptre, A. J., Bizumuremyi, J.B., Uwimana, F. & Ndaruhebeye, J.D. (1997) The effects of the Rwandan civil war on
poaching of ungulates in the Parc National des Volcans. Oryx, 31, 265-273. Plumptre, A.J. & Williamson, E.A. (2001) Conservation-oriented research in the Virunga region. In Mountain Gorilla:
Three Decades of Research at Karisoke (eds M.M. Robbins, P. Sicotte & K.J. Stewart), pp. 361-389. Cambridge University Press, Cambridge, UK.
Plumptre, A.J., Behangana, M., Davenport, T., Kahindo, C., Kityo, R., Ndomba, E., Ssegawa, P., Eilu, G., Nkuutu, D. &
Owiunji, I. (2003) The Biodiversity of the Albertine Rift. Albertine Rift Technical Reports No. 3 Robbins, M.M. (1995) A demographic analysis of male life history and social structure of mountain gorillas.
Behaviour, 132, 21-47. Robbins, M.M., & Robbins, A.M. (2004) Simulation of the population dynamics and social structure of the Virunga
mountain gorillas. Am J Primatol. 63: 201-223. Schaller, G.B. (1963) The mountain gorilla: ecology and behaviour. University of Chicago Press, Chicago. Sholley, C. (1991) Conserving gorillas in the midst of guerrillas. African Wildlife Foundation. In American
Association of Zoological Parks and Aquariums, Annual Conference Proceedings, pp. 30-37. Sikubwabo Kiyengo, C. & Mushenzi Lusenge, N. (1997). Mountain gorillas of Mikeno, Zaïre: an explosive situation.
Gorilla Conservation News, 11, 13-14. Steklis, D. & Gerald-Steklis, N. (2001) Status of the Virunga mountain gorilla population. In Mountain Gorilla: Three
Decades of Research at Karisoke (eds M.M. Robbins, P. Sicotte & K.J. Stewart), pp. 391-412. Cambridge University Press, Cambridge, UK.
Vedder, A. & Aveling, C. (1986) Census of the Virunga population of Gorilla gorilla beringei. Coordinator's report.
September 1986. Weber, A.W. & Vedder, A. (1983) Population Dynamics of the Virunga Gorillas: 1959-1978. Biological Conservation,
26, 341-366. Weber, W. (1987) Ruhengeri and its Resources: An Environmental Profile of the Ruhengeri Prefecture, Rwanda.
United States Agency for International Development: 92.