West Africa sentinel landscape

The West Africa sentinel landscape (WASL) is found within a transect that spans the northeast of Mali (Sikasso, Koutiala and Bougouni), Burkina Faso (Bobo Dioulasso, Banfora, Koungoussi and Lake Bam, Ouagadougou, Leo, Fada Ngourma and the W Park), northern Ghana (Wa, Lawra, Djirapa, Sabuli, Ping, Heng and Tamale, including the Gbele Game Production Reserve), and northern Togo (Dapaong and Mango including the “Fosse aux Lions” National Park). This transect also includes the Niger Basin (southeast Mali) and the Volta Basin (Burkina Faso, northern Ghana and northern Togo).

Research is generating data on landscape performance over time, to permit identification and interpretation of these thresholds with respect to potential impacts on poverty, food security, human nutrition and sustainable natural resource management.

The main purpose of this analysis is to better understand how humans relate to trees within landscapes, and the corresponding and retro-implications for both humans and tree ecosystems.

In order to do this, it is important to obtain knowledge of landscape units and components, human activities and land-use types, the change in processes and their effects, as well as how they can enhance or impede the stated management objectives.

Site selection

Discussion with local and prospective partners from all four countries
Drivers of change identified at landscape scale
Site selection criteria:
Gradient of change with old change processes and more recent change processes
Potential colocation of CGIAR and other partners
Accessibility and security
Climatic effect control
Two “sentinel” sites selected per country, representing extremes in landscape change trajectories
Burkina Faso and Ghana retained as pilots for baselines due to available resources


Situated in Bam province, Center North region, Kongoussi is 110 km from Ouagadougou.
Vast peneplain, featuring a few hills and some valleys with an average altitude between 350-400 m above sea level (asl) and brown ferrous soils.
Soudano-sahelian climate with a four-month rainy season and total precipitation of 600-750 mm. Temperatures vary from 17° C in December or January to 44° C in April or May.
Tree savannah in the south and steppes in the north make up the vegetation.
275,191 inhabitants in the 2006 census, estimated to be 305,859 by 2010 and an urbanization rate of 9.1%.
Dispersed households within settlements.
Presence of a church, mosque, primary and secondary schools, as well as a departmental road.
Agriculture has traditionally been the main economic activity with cereals (maize, millet and sorghum) cultivated during the rainy season and market gardening on the banks of Bam Lake during the dry season. Unfortunately, cereal production is no longer sufficient to meet the needs of the local population.
Traditional extensive animal rearing is the second-most important activity, with cows, goats, sheep, chicken and guinea fowl being reared.
Both artisanal and industrial mining are present and increasingly important, but also responsible for much of the migration in the region.


100 km from Ouagadougou, Cassou is within Ziro province, which has four departments: Bakata, Bougnounou, Cassou and Gao.
Generally flat relief. South Soudanian climate, 800 mm to 1,100 mm (June to September) of rainfall.
Shrub and tree savannah, as well as gallery forests (along the Mohoun and Nazinon rivers).
175,607 inhabitants of this province (2006 population census figures) estimated to be 199,934 by 2010, spread across 128 villages.
Four ethnic groups cohabit with native Gourounsi (Nouni) and migrant Mossi, Peulh and Walla communities.
Dispersed households within settlements, presence of a church, mosque, primary and secondary schools, as well as both regional and departmental roads.
Agriculture, animal rearing and fuelwood production are the main livelihood activities. Major crops include cotton, red and white sorghum, millet, maize and vegetables. Rearing of chicken, goats and sheep is also common in this area.
A key feature of Cassou is the presence of the “Chantier d’Amenagement Forestiere” (CAF) of Cassou and Bougnounou.
Water catchments are a determinant for livelihood activities.


Sissala East District (7,115 km2) is one of nine districts in the Upper West region of north Ghana and within the Kingdom of Dagbon. It shares a 300 km border with Burkina to the north and its capital is Tumu.
Gently undulating topography between 330–365 m in the north to 220 m and 290 m in the Sissili valley.
Guinea savannah vegetation belt with grasses and scattered fire-resistant trees.
Population: 60,992 inhabitants (2014); density: 7.2 hab./km2 with high in-migration of Fulani (Peuhls).
Ethnic groups include Sissala (80%), Fulani, Dagarti and some Akans. The Sissala are further divided into castes: the Hanviarahs, Kpeviarahs, Buviarahs, Yebaviarahs, Heliviarahs, etc.
Highly dispersed settlements at least 10 km apart, but extremely clustered houses are sometimes contiguous. Houses are built with mud bricks and roofed with thatch and zinc.
Important sources of income among the people are farming (maize, yam, beans, groundnut, rice, cotton, bambara beans, etc.), livestock rearing (sheep, goats, pigs, poultry) and trading.
Domestic firewood, charcoal, construction and fencing materials and fodder are among the available ecosystem services.


One of nine districts and municipalities in the Upper East region of north Ghana, Bawku municipal district (1,275 km2), has the city of Bawku as its capital.
International boundaries with Burkina Faso (north) and Togo (to the east).
Highest point of the Upper East region. Generally low (120-150 m asl.) and slightly undulating relief close to White Volta River Basin and plateau surfaces elsewhere with a mean altitude of 400 m asl.
Pronounced dry (late November-early March) and wet seasons (May-October) and average total rainfall of 800 m per annum.
Drained mainly by the White Volta and its tributaries. Other streams include Kulupielega and the Poanaba Kayinchingo. Seasonal flooding is a landscape feature.
Sahel Savannah type vegetation with fire-swept grassland separating deciduous trees among which may be seen a few broad-leaved and fire-leached tree species. Forest reserves include Morago West, Kuka and the White Volta Basin.
Population: 69,527 inhabitants (Kusasis [Kusaal], 2012); density: 140-170 hab./km2 and indigenous inhabitant population, cohabiting with Mamprusis, Bissas and Mosis, but large immigrant populations from other locations in northern and southern Ghana as well as from Burkina Faso, Ivory Coast, Togo, Niger and Nigeria.
Strong agricultural area with millet, sorghum, maize, tomatoes, soya beans and onions among the main crops.


Scattered homesteads, easily accessible
Church, mosque, primary and secondary schools
Departmental road


Forested environment
Scattered homesteads
High in-migration
Church, mosque, primary and secondary schools
Departmental and regional roads


Forested environment
Clustered homesteads
High in-migration
Church, mosque, primary and secondary schools
Departmental and regional roads
1. Village Survey
Kongoussi (Burkina Faso)
10 communities
422 participants
392 forms (stage of poverty, settlement form, forest form, product form, association form)
Cassou (Burkina Faso)
18 communities
606 participants
718 forms (stage of poverty, settlement form, forest form, product form, association form)
Walembelle (Ghana)
18 communities
572 participants
666 forms (stage of poverty, settlement form, forest form, product form, association form)
2. Household Survey
Kongoussi (Burkina Faso)
10 communities
300 households
300 forms (sentinel landscape household module)
Cassou (Burkina Faso)
10 communities
300 households
300 forms (sentinel landscape household module)
Walembelle (Ghana)
10 communities
300 households
300 forms (sentinel landscape household module)
3. Land Degradation and Surveillance Framework (LDSF)
Two sites sampled:
Kongoussi (Burkina Faso)
Cassou (Burkina Faso)
Two more to be sampled:
Walembelle (Ghana)
Bawku (Ghana)
Land degradation and surveillance framework (LDSF) ground sampling hierarchy:
Level Area (ha) Number
Sentinel site 10,000 4
Cluster 100 16 per sentinel site
Plot 0.1 10 per cluster
Sub-plot 0.01 4 per plot
LDSF ground sampling measurements:
Land-use history and land cover
Composite soil samples
Vegetation description
Biophysical constraints measurement
Erosion prevalence
Above-ground biodiversity
Woody cover and distribution

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