Wetlands in drylands in the Sahel: the urgent need for good joint governance
Brouwer Envir. & Agric. Consultancy, Bennekom, The Netherlands BrouwerEAC@online.nl
In dryland regions wetlands stand out as areas where water and nutrients accumulate, plant and animal production potential is high, and production risk is low. Wetlands are therefore much sought after in dryland regions, by farmers, pastoralists, fishermen, collectors of natural products, and also wildlife. Economic data from reports on some of the 1,000 isolated wetlands in Niger demonstrate this importance, to people living at the isolated wetlands as well to people living farther away, during ‘normal’ years as well as in times of drought. At the same time the isolated wetlands are under threat of disappearing because of increasing human pressure, climate change, land use change in their catchments, etc. Descriptions of selected wetlands in Niger visited in the mid-1990s and again twelve years later show this, too. Good governance, i.e. integrated and participative management, of wetlands in dryland regions must be effectuated as soon as possible, so that these very important natural resources will be used wisely and sustainably and not used up. A case study from Lake Tabalak illustrates this.
Keywords: Sahel, isolated wetlands, economic value, threatened ecosystems, participatory integrated management.
Water is what makes life on Earth possible. It is no different in the arid and semi-arid regions of the world, where rainfall is notoriously undependable. Wetlands are areas where water is concentrated and water supply dependable, thus reducing production risk. Nutrients from sediments and livestock manure are concentrated at wetlands as well, thus increasing ecological and agricultural production potential in comparison with the surrounding drylands. Because of this low production risk and high production potential, wetlands in arid and semi-arid regions are much sought after by people as well as animals. These wetlands also facilitate the utilisation of the drylands surrounding them. In short, in dryland areas wetlands are extremely important resources.
Unfortunately wetlands in dryland areas are also under severe threat. These threats include conflicts of interests between different users and user groups, desertification, climate change, demographic change and socio-economic change, as well as lack of good governance.
In this paper I use the isolated inland wetlands of Niger to illustrate the value of wetlands, and their importance for the functioning of the surrounding dryland ecosystems. First, the various types of wetlands that occur in Niger are discussed. This is followed by a description of their use for different purposes, during the wet season as well as the dry season, and during normal and dry years. Next some economic values of isolated wetlands in Niger to different user groups are quantified. After this interactions between different types of wetland use, and between wetlands and surrounding uplands, are discussed. Recent trends and present and future threats to these wetlands are reviewed as well, followed by an illustrative case study from Lake Tabalak in west central Niger. In the final section conclusions are drawn, and governance recommendations made.
WETLAND TYPES IN NIGER
The few large floodplains
Niger contains a number of large floodplains. These occur along 550 km of the river Niger in the south-west of the country; along 180 km of the Komadougou-Yobé forming the border with Nigeria in the south-east of the country; and along some 100 km of the former shore of Lake Chad in the extreme south-east ((MHE-Niger 1990a, 1991a). While these floodplains are very importantly ecologically and economically, also for the dryland regions that surround them, they are not the objective of this chapter.
In the north of Niger there are a number of oases, with orchards, grape and date production (de Beaufort and Czajkowski 1986; MHE-Niger 1991d). Little information is available about these wetlands. Throughout the country there are also a number of dry, 'fossil' valleys, sometimes kilometres wide, dating from the time that the Sahara and Sahel were much wetter than now, approximately 6-10,000 years ago. In most of these valleys water hasn't flown for centuries. Some still carry water from time to time, but in these ancient valleys groundwater is often close to the surface. (MHE-Niger 1990a-e, 1991b-c)
Most importantly, there are a large number of more or less isolated inland wetlands or lakes, called ‘mares’ in French. They are often located in depressions in the old drainage systems. There are more than 1000 in Niger alone, varying in size between 10 and 2000 ha at maximum extent. Some are very temporary, and only hold water a couple of months each year. Others contain water much longer. A number are even permanent, and always, or almost always, have water (MHE-DRE-Niger 1993). These wetlands are enormously dynamic. Some disappear due to silting up (MHE-Niger 1992; Piaton and Puech 1992), but new ones appear as well. One such new wetland is at Dan Doutchi, in a depression that filled up as the drought broke in 1975: it now covers 1800 ha when full (Brouwer and Mullié 1994b). By far the greatest number of these isolated wetlands is to be found south of 15° N, in approximately the 300-600 mm rainfall zone, also called the Sahel zone. The northern limit is roughly the line from the SE corner of Mali across the departments of Tahoua, Zinder and Diffa to Lake Chad. The southern limit is more or less formed by the borders with Nigeria, Benin and Burkina Faso. In other countries of the Sahel zone isolated wetland prevalence is without any doubt similar. In south-eastern Mauritania, for instance, there are at least 244 isolated wetlands of appreciable size (Cooper et al. 2006).