Conservation of Chimpanzees and Gorillas in Western Equatorial Africa
A plan that identifies the priority sites and actions needed to promote
the conservation of the two subspecies of ape, western lowland gorillas
(Gorilla gorilla gorilla) and central chimpanzees (Pan troglodytes
troglodytes), across their shared geographic range was recently completed.
It was the major outcome of a workshop that brought together 70 experts,
including re-searchers, government representatives and conservation managers
in Brazzaville in May 2005. The workshop and publication were supported
by grants from United States Fish and Wildlife Service Great Ape
Conservation Fund, the UNEP/UNESCO Great Ape Survival Project (GRASP),
the Cleveland Park Zoological Society, the Primate Action Fund,
the Centre International de Recherches Médicale de Franceville,
Gabon, the French Ministry of Foreign Affairs, the Wildlife Conservation
Society, the Center for Applied Biodiversity Science at Conservation
International and the Wild Chimpanzee Foundation.
Surveys in western equatorial Africa in the 1980s indicated that healthy
populations of both gorillas and chimpanzees existed in many areas remote
from human settlements.
However, despite the fact that this region has one of the lowest human
population densities of any tropical forest area in the world, ape populations
are, today, in dramatic decline. This is largely because of increased
commercial hunting, the spread of logging, which alters forest structure
and facilitates poaching, and because of Ebola haemorrhagic fever. There
are many site-based, national and international projects that work to
conserve great apes in this region, but the continuing, rapid decline
indicates that past efforts are not sufficient, and that more is needed.
The aim of the action plan is to provide a clear investment plan for researchers,
conservationists, and donors and, most importantly, to assist habitat
country governments in developing strategies for the conservation of great
apes.
Priority populations were identified during the workshop using the best
available data and a set of criteria to evaluate population size, area
of site and the importance of the site for bio-diversity in general. Methodological
problems precluded consistent reliable distinction between gorilla and
chimpanzee nests and, in addition, many surveys were conducted more than
5 years ago. Thus, workshop participants agreed to adopt the precautionary
principle in considering numbers of "apes" (rather than gorillas
and chimpanzees separately) and a post-hoc evaluation of the quality of
the population estimate for each site was made. Twelve priority areas
were identified as well as 2 areas where present data are inadequate to
assess their importance for ape conservation as are priority sites for
surveys. These areas, listed in the table below, cover over 150,000 km²
of priority habitat for the protection of gorillas and chimpanzees and
contain the largest populations remaining in the region. The majority
of the priority sites include existing protected areas with buffer zones
of forests allocated as commercial logging concessions.
Priority Areas for the conservation of great apes
in western Equatorial Africa
Map: Stephen Blake/WCS
Preparation for the Brazzaville workshop included the development of
the APES database (Ape Populations, Environments and Surveys) by researchers
at the Max Planck Institute for Evolutionary Anthropology. This revealed
the extensive knowledge gaps that remain, and clear research priorities
emerged at the workshop, including the urgent need to improve census methods
and our ability to monitor trends in ape populations over time.
In addition, the emergence of Ebola as a major threat to apes in this
region has dramatically complicated the challenge of protecting apes.
Since the early 1990s, repeated outbreaks of Ebola have very drastically
reduced ape numbers in large regions of northern Gabon and northern Congo,
and there are current epidemics in Odzala-Koukoua National Park. Research
on possible -Ebola containment strategies will require new alliances between
laboratory and field-based scientists in a range of disciplines, including
virology, epidemiology, ecology and conservation, as well as logistical
support from habitat country governments and health authorities. Without
new focussed research to reduce these knowledge gaps the design of conservation
strategy and the effectiveness of implementation will remain compromised.
The three major threats to apes in western equatorial Africa are poaching,
disease and the spread of logging into remote forest blocks. Commercial
hunting for the bushmeat trade was identified as a major threat at all
of the priority ape conservation sites. Ebola currently threatens apes
in the exceptional priority site of Odzala and is a potential future threat
elsewhere. Logging emerged as a significant threat especially in concessions
surrounding protected areas. Without strict control, the roads and transport
opportunities created by industrial logging systematically lead to a massive
increase in commercial bushmeat hunting. The action plan summarizes debate
at the workshop in the form of recommendations for the immediate and longer-term
mitigation actions that are needed at a regional level.
Western lowland gorilla and chimpanzee populations in western equatorial
Africa are in steep decline. We do not know exactly how many remain, but
the alarming average annual rate of decline of 4.7% in Gabon between 1983-2000
and the high mortality (>80%) recorded in two studied populations affected
by Ebola underline a critical state for conservation and the need for
urgent reinforcement of their protection.
The protection of the 12 priority ape populations identified in the regional
action plan would guarantee, if successfully implemented, the survival
of the majority of apes remaining in western equatorial Africa. The consensus
reached on a clear list of the most urgently needed activities for each
site provides strong conservation strategies for the immediate future
and we estimate that, with about 30 million dollars over the next 5 years,
this could be achieved. We hope that funding agencies will understand
the urgency of the situation and seize the opportunity to support such
a broad agreement.
Priority
areas for the conservation of chimpanzees and gorillas in western equatorial
Africa as determined by consensus at the 2005 workshop in Brazzaville
Population size: 5 >4,000 apes; 4 >2,000;
3 >1,000; 2 >500; 1 >250. Area of site: 5 >16,000 km²;
4 >8,000 km²; 3 >4,000 km²; 2 >2,000 km²; 1 >1,000
km². Importance for conservation and sustainable forest management,
attributed at the 2000 WWF-sponsored Libreville biodiversity vision workshop:
4 highest; 3 high; 2 medium; 1 low. Quality of data available for the
estimate of ape population size, based on the time elapsed since the data
were collected and methodology: 1 unsubstantiated (presence/absence or
surveys undertaken before 2000); 2 low quality (Recce surveys after 2000,
or single transect survey after 2000, with <50 km survey effort); 3
minimal quality (single transect survey after 2000 with >50 km effort
in a specific area, or multiple transect surveys after 2000 with <50
km effort in different areas); 4 good quality (multiple transect surveys
after 2000 with >=50 km effort in different areas); 5 best quality
(multiple transect surveys after 2000 with >=50 km effort in different
areas and nest decay rate available for the area and density estimate
The list of priority sites is not "set in stone", nor are
their geographical boundaries, as conditions can change rapidly and some
areas, such as the two identified, need surveys to establish the present
status of apes, while others were too small in size to be included but
contain populations that may have long-term viability. Without effective
monitoring of wild ape numbers and health status, optimal conservation
will not be possible; there is, therefore, extreme urgency to advance
applied research on these issues in addition to reinforced multi-disciplinary
investigation of Ebola prevention in the face of this extremely potent
new threat.
It is illegal to kill or capture apes in all of the habitat countries
of Pan troglodytes troglodytes and Gorilla gorilla gorilla,
thus law enforcement is the central thread of the conservation strategy.
Effective law enforcement requires a huge investment but, given this,
it would have an immediate positive effect for apes. In the face of the
staggering ongoing decline, dampening the impact of commercial hunting
on apes is the easiest action to implement - through arrest and prosecution
of poachers, and through control of access and transport opportunities
in the key protected areas and logging concessions identified as ape strongholds.
Clearly, enforcement must be accompanied by awareness and education campaigns
and the creation of jobs and appropriate incentive systems for rural populations.
Once an ape population is reduced by hunting or disease, its capacity
to recover is very limited, due to very slow reproduction and complex
social behaviour. Females give birth for the first time at about 12 years
of age for gorillas and 14 for chimpanzees. Thereafter they give birth
only once every 5 to 6 years. Even with perfect protection from hunting,
it would take roughly 150 years for populations to recover from high levels
of mortality documented in past Ebola epidemics.
The "natural protection" afforded in the past by the large remaining
blocks of forest habitat isolated from human activities is eroding as
logging spreads into the most remote parts of the western equatorial region
of Africa. The addition of Ebola to poaching and habitat loss has created
a potent cocktail of threats to apes in this region. Strong political
will for conservation and environmental protection exists in western equatorial
Africa, as well as mechanisms for cooperation at a regional level. This
provides hope that, with increased international aid, implementation of
the recommendations of the expert group who met in Brazzaville in May
2005 can be achieved quickly and this will make a very significant difference
to the survival of chimpanzee and gorillas in these six countries.
Caroline Tutin, Emma Stokes, Rebecca Kormos, Christophe Boesch
Regional Action Plan for the Conservation of Chimpanzees
and Gorillas in Western Equatorial Africa (2005). Compiled and edited
by: Caroline Tutin, Emma Stokes, Christophe Boesch, David Morgan, Crickette
Sanz, Trish Reed, Allard Blom, Peter Walsh, Steve Blake & Rebecca Kormos.
Conservation International, Washington DC. 36 pages
Plan d'action regional pour la conservation des chimpanzés et des gorilles
en Afrique Centrale (2005). Compilé et édité par: Caroline Tutin, Emma
Stokes, Christophe Boesch, David Morgan, Crickette Sanz, Trish Reed, Allard
Blom, Peter Walsh, Steve Blake & Rebecca Kormos. Conservation International,
Washington DC. 36 pages
The regional action plan is available in pdf format in English or
in French. Please contact Rebecca Kormos (r.kormos (at) conservation.org)
Dr. Caroline Tutin spent 22 years studying gorillas
and chimpanzees in Gabon and now concentrates on promoting ape conservation.
Dr. Emma Stokes is Research Coordinator for the Nouabalé-Ndoki
National Park in northern Congo with the Wildlife Conservation Society-Congo
and a specialist in gorilla social organisation and behaviour.
Dr. Rebecca Kormos is a Research Fellow at the Center for
Applied Biodiversity Science, Conservation International, and Vice-Chair,
Section on Great Apes of the IUCN/SSC Primate Specialist Group.
Dr. Christophe Boesch is Director of the Max Planck Institute for
Evolutionary Anthropology and President of the Wild Chimpanzee Foundation.
He studied chimpanzees in the Tai Forest, Ivory Coast, for over 20 years
and more recently has begun work in on gorillas and chimpanzees in Gabon.