Wetlands are of enormous importance to Africa. They are economic hotspots, primarily because of the food the people living in them are able to produce. They are also sensitive to ecological change and
are attractive to other land users such as intensive agriculture and industrialization (Adams 1992) - a tricky combination. Wetlands constitute roughly 4.7% of the
continental area of Sub-Saharan Africa (Lehner and Döll 2004, quoted in Rebelo et al 2010), but, as suggested
by Adams and as I have learned in writing this post, this relatively small
figure is dwarfed by the significant benefits they provide to millions of
people, livestock and wildlife, not to mention whole unique ecosystems. Here, I
want to take a general look at the benefits of wetlands (primarily floodplains)
in Sub-Saharan Africa, and find that the difficulty of quantifying
benefits derived from them is a key problem facing their successful management.
There are various services provided by African wetlands which we might
call economically ‘valuable’, and quantifying these can help wetlands to be
taken more seriously by planners in a neoliberal world, where economic value
increasingly trumps all other values. Barbier et al. (1991) attempted to
calculate the total value of agricultural, fishing and fuelwood benefits to the
people of the Hadeji-Jama’are wetlands. They calculated its value at N850-1280
per hectare, or N240-370 and N375-565 per 103m3 of water
for ‘maximum’ and ‘minimum’ flood input values respectively. However, as they
concede, most aspects of wetlands in Africa resist easy quantification.
Many African wetlands and their catchments are strongly influenced
by the Inter-tropical convergence zone, or ITCZ, and therefore experience
highly seasonal rainfall, and thus seasonal flooding. This flooding is a vital
ecosystem and agricultural service. Floodwaters rich with nutrients ideal for
growing crops and grass for cattle grazing deposit their loads across vast
areas (at one time up to 3000km2 of the Hadejia-Jama'are
Floodplain in Nigeria flooded annually). This silt and solid mineral deposition
usually means farmers have no need to fallow their fields. Not only this, but floodwaters go some way to meeting evaporative demand, and therefore
plants in floodplains are able to use more of the available solar energy,
yielding better crops with less effort.
Given this, it’s no surprise that agriculture thrives in
wetlands, sustaining populations generally much denser than those found
elsewhere. The Niger Inland Delta alone supports 550,000 people, grazing for
about 1-1.5 million cattle, 1 million sheep and goats and 0.7m camels. Although
not the focus of this post, I shouldn’t brush over the fact that all this
agricultural productivity isn’t just handed to wetland residents on a plate; it
has required decades and centuries of the gradual improvement of indigenous
knowledges and practises that, as Adams demonstrates, often make phenomenally
efficient use of the land and of the water.
In the drier months, wetlands take on an importance far beyond their
size. Adams points out that a relatively small area of fertile wetland can help
support nomadic pastoralists (such as the Fulani) and large amounts of their accompanying
cattle at a critical juncture in the year, when surrounding rangelands are
drying out. These pastoralists in the wet season may be nowhere near the
wetlands, but it is only through the existence of the wetlands that they can
survive the driest months.
Additionally, floodplains rich in nutrients are excellent
at sustaining huge amounts of aquatic vegetation, microorganisms and
invertebrates, come the seasonal floods. This makes fishing in African wetlands
a productive activity and one that can be practised most of
the year using simple ‘bunds’ to cut off flooded areas from the retreating
floodwaters. The harvesting and exportation of fuelwood, echinochloa and other plants can also be of ‘considerable economic significance’(Barbier et al. 1991). Given the necessary
infrastructural investment, wetlands in Africa are also capable of providing
scientific, educational and tourism benefits.
Seasonal flooding of wetlands also recharges groundwater-supplying
aquifers in areas far outside their own surface extent, for example Lake Chad is recharged by flooding in the Hadeji-Jama'are basin hundreds of kilometres away. In this way, the benefits of wetlands are more far-reaching than the wetlands themselves. Exact measuring of
recharge is however a difficult, albeit ‘not
insurmountable’ challenge (Barbier et al 1991).
Wetlands are incredibly biodiverse places and are valued by the conservation community, as demonstrated by the Ramsar convention of 1971 that designates special international importance to specific wetland areas, of which there are now hundreds in Africa alone. However, the ecosystem services of wetlands are almost impossible to attach a monetary value to, although all sorts of methods and categorisations have been tried (Robertson 2012).
I've skirted around the problems facing African wetlands in this post, but I hope to get back to them in future posts. I will say this; that as capitalism and cultures of quantification, growth and development have largely been imposed upon Africa by a hegemonic Global North, and as it is these systems that frequently lead to the undervaluation of many of the significant benefits provided by wetlands, it is likely that without a (incredibly unlikely) global overthrow of the market-oriented neoliberal paradigm, the wide-ranging benefits of wetlands (and so many more ecosystems) described above will continue to be undervalued.
References
Adams, W., (1992) Wasting the Rain,
London: Earthscan.
Barbier, E.B., Adams, W.M. and Kimmage, K., 1991.
Economic Valuation of Wetland Benefits: The Hadejia-Jama’are Floodplain,
Nigeria , London Environmental Economics Centre Discussion Paper DP 91-02.
International Institute for Environment and Development, London.
Lehner and Döll (2004) Development and validation of a global database
of lakes, reservoirs and wetlands. J Hydrol (Amst) 296(1–4):1–22.
doi:10.1016/j.jhydrol.2004.03.028
Robertson, M. (2012) 'Measurement and alienation: making a world of ecosystem services', Transactions of the institute of British geographers, NS 37., 386-401.
Robertson, M. (2012) 'Measurement and alienation: making a world of ecosystem services', Transactions of the institute of British geographers, NS 37., 386-401.
