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Tropical Forest Research Network |
BIODIVERSITY CONSERVATION THROUGH BURNING: A CASE STUDY OF WOODLANDS IN THE BUDONGO FOREST RESERVE, NW UGANDA
By Grace Nangendo, Oliver van Straaten and Alfred de Gier
In order to determine suitable areas for conservation, it is important that the spatial dynamics and the forces fostering that dynamic change be understood. The Budongo Forest Reserve, located in north-western Uganda, is one of the forests that have been identified as having a high biodiversity. The forest is composed of 53.7% tropical high forest and 46.3% woodlands. The Budongo Forest has been under central government management (specifically of the Forest Department) since 1948. In the mid 1980s, the Uganda Wildlife Authority (UWA) joined forces with regard to management of the forest. At the same time, the local people have maintained the woodlands within the forest area for hundreds of years.
In the woodlands (here defined as formations with a discontinuous tree layer but with a coverage of at least 10% and less than 40%, and generally with a continuous grass layer) local stakeholders used fire as a tool for hunting and for maintaining an open environment suitable for animal grazing. Many such ecosystems that experience fire disturbances over long periods consequently develop a unique species pool adapted to fire. However, in the absence of such disturbances, various ecological changes occur within such ecosystems.
The woodlands within Budongo Forest Reserve were selected for a case study to determine spatial changes in the absence of fire. The spatial extent of vegetation changes were mapped using satellite imagery over a 17-year period from 1985 to 2002. Temporal NDVI image differencing and visual interpretation techniques were used to determine areas of vegetation change. The 2002 satellite image of the area was classified so as to generate a map of the existing cover types. In this paper, the output of the above-mentioned study is linked to an earlier study of the mechanisms used by local people who used fire for hunting purposes so as to understand the role of local people in maintaining the heterogeneous landscape.
Vegetation change following
fire prevention
Due to increased fire prevention measures imposed throughout the past two decades,
there has been a net increase in vegetation cover, with the surrounding forest
encroaching into the woodland. The classified image shows various cover types
. The recently burnt areas, however, show an interesting phenomenon: along the
northern side of the forest, an area controlled by UWA management alone, the
recently burnt parts are generally large, while those along the southern side,
near the local people, being small and far apart. In between these two parts
there is no indication of recently burnt areas. In an earlier study, it was
observed that local people's fires are systematically set and controlled. They
are also spatially varied over time. It can therefore be deduced that if the
current fire control measures are maintained, there will be homogeneous woodland
in the North and heterogeneous woodland in the south, with the central area
being left to grow into forest unchecked. Heterogeneous woodland would be more
advantageous since it is likely to have more species than a homogeneous one,
which - if added to the already existing forest - would lead to an increase
in the biodiversity level of the forest reserve.
The vegetation changes in the area can mainly be explained by two major events that took place in the mid 1980s, i.e. the movement of the UWA gate from the Northern boundary of the forest to the southern boundary and the establishment of an ecotourism site by the Forestry Department along the only access road through the forest. The gate has created a checkpoint for all who enter the forest area. At the same time, the local people also avoid making fires anywhere close to the ecotourism site. Because of the dual management of the forest area, there is no clear understanding of the policies that play a role. While the UWA authority utilises early burning as a way of establishing fresh grass for the animals, the Forestry Department recommends the same in the woodland areas. The foresters on the ground, however, hardly ever carry out the burning work and rely on the now 'illegal' local people to do the burning instead. However, the current heavy policing of the area by the UWA means local people are unable to access the protected area.
The need for balanced
fire management
To encourage the local people to stay away from the protected area, revenue-sharing
programmes and income-generating projects have been set up. The children in
the surrounding schools are also being taught about the value of conservation.
While this may succeed, one problem still remains: by whom and when are the
fires in the woodlands to be set? Is the management willing to learn from the
local people who have maintained the woodland set up of this area for hundreds
of years? Are we, foresters, willing to come down and admit especially to the
local people, that fire is not always an evil to be avoided and that it is beneficial
to certain ecosystems such as woodlands?
For the purpose of maintaining a dynamic landscape, where both the forest and the woodland communities co-exist in the future, it is important that fire disturbance regimes be managed consciously. Sustainable woodland management would require a balance between fire restriction and fire establishment to control and shift the ecosystem to suit future management objectives.
Further information:
Grace Nangendo
Department of Natural Resources, International Institute for Geo-Information
Science & Earth Observation (ITC)
PO Box 6
Hengelosestraat 99
7500 AA Enschede
The Netherlands
E-mail: nangendo@itc.nl