Contested Understandings of Ecosystem Services

Blog Four-Ecosystem Services Critique

I initially intended for my fourth blog to continue and expand on the discussion of wetlands and ecosystem services. However, having come across an interesting review paper which looks at Ecosystem Services more conceptually, this blog will step back from the wetlands focus. Instead it will centre on discussing conceptual critiques of ecosystem services, through assessment of some aspects relevant to Water and Development in the academic papers: ‘Ecosystems service as a Contested Concept’ (Schroter, et al., 2014), as well as mentioning several other relevant supporting literatures.

The Schroter paper outlines recurring critiques of the Ecosystem Services concepts, as well as counter-arguments to these, and an ‘envisioned way forward’ from this. The authors highlight seven points of criticism of ecosystem services, and split these into three categories of critique; ethical concerns, strategy flaws in conceptions of Ecosystem Services, and criticisms related to Ecosystem Services as sciences. These are shown in a reduced version of a table from the article.

Category	Point of Criticism	Argument
Ethical Concerns	Environmental Ethics	Excludes natures intrinsic value
	Human-Nature Relationship	Aids exploitative H-N relation
Strategy Flaws	Conflicts with concept of biodiversity	Could replace biodiversity aims
	Valuation	Often reliant on economic valuation
	Commodification	Based on payment protecting ES
Criticisms of ES as Science	Vagueness	Vaguely defined ‘catch-all’
	Optimistic Assumptions	Sees nature as always beneficial

This table illustrates that there are clear flaws with the ES concept. The main arguments from the paper which are of particular relevance to Water and Development in Africa are those linked to ethical concerns and strategy flaws. Predominantly, this is as ES revolves around perceiving nature as a resource, something to be manipulated for human benefit, with the only conceptions which can help to protect it being monetary valuations. ES becomes just a managerial interference with nature, whether that be in attempts to protect or safeguard nature, or in providing necessary usages. Of course it is important to meet needs for people, particularly in developing and water scarce areas such as much of Africa. However this should also be in a way that protects ‘the flora and fauna that we see around us in all their diversity are both priceless and worthless’ (Reid, 2012), with value far beyond these usage ones, and the ES focus on economic value and provision can conflict with the concept of biodiversity. This is deeply problematic in a market driven world where valuation is arguably pivotal in any attempt to integrate environmental protection into wider agendas.

However, despite outlining multiple criticisms of Ecosystem Services,  Schroter et al go on to offer both counter arguments to each, as well as ways forwards. Of particular relevance in an African context is the counter-arguments to environmental ethics and the human-nature relation. These focus on the understanding that ES contains valid anthropocentric arguments, and that recognition of need for biodiversity to support human ways of life can aid arguments to protect the environment and improve societal connections to nature. Relatedly, linked concerns to valuation and commodification can begin to be overcome, through recognition that they are simply tools to aid decision making, allowing informed development whilst maintaining ecosystem services and biodiversity. These don’t resolve the issues of ES, and still reduces nature to a resource in some regard. Nonetheless, it is important to recognise that they could be useful in some contexts and situations, and offer a novel and interesting technique, despite their flaws. Essentially, they are the necessary and pragmatic approach to nature conservation that we need.

In my next blog I intend to take these ideas and apply them more directly to Africa and Wetlands, as well as beginning to broach discussion between rural and urban ecosystem service utilisation.

Wetlands and Ecosystem Services

Wetlands Importance for providing Ecosystem Services in Africa

This third blog will move on from wider context of seasonal variability in climate and water availability to look at a specific example of Ecosystem Service in the context of Africa, floodplain wetlands. The importance of these areas is closely linked to the variability described in my previous blog.  Discussion of this will help to illustrate exactly what an ecosystem service is and how it works, and begin to look at a few of the consequences of such a conception.

Floodplain wetlands provide such useful insights as a case study of water as an ecosystem service in Africa as they impacted by several specific and unique aspects of African ecosystems and topography, whilst providing an array of complex services linked to this.

These wetlands can be found across Africa, although they are of particular significance in regions which experience high seasonal variability, areas which are made up predominantly of the Savanna eco-region and sub-tropical steppe, shown below in the diagram of Baileys Eco-Regions. This shows the distribution of Wetlands of International Significance, also known as Ramsar sites, within these various eco-regions (Rebelo, et al., 2010).

Fig. 2 Baileys ecoregions and the location of Ramsar wetland sites Source-Rebelo Article

Wetlands provide a host of ecosystem services, both in direct human usages of water, such as domestic, industrial and irrigation use, but also through helping provide ‘forage and hunting resources, wood resources, grazing, fish and agricultural produce’ (Adams, 1993). Furthermore, they also contribute to natural processes such as aquifer recharge, flood control and through nutrient transfer, aspects which are incredibly important but are harder to assess in terms of ecosystem services, and so may be overlooked.

It is within dryland Africa that the economic importance of wetlands is greatest, so much so that their impact is described as being ‘out of all proportion to their size’ (Adams, 1993). This is as they help to regulate the impacts of seasonal variability in precipitation in Africa, as topography, past sediment deposition and erosion lead to flooding of certain areas. The length of inundation varies massively, but regardless helps to regulate ecosystem service provision as they delay and lower the peak of flood flows, whilst helping to produce outputs that serve communities in differing ways throughout the year.

For example in several river basins in Nigeria, such as the Hadejia-Jama'are, at the peak of inundation crops like rice and sugar cane which can tolerate flood conditions are planted, whilst once the waters begin to recede other crops such as millet and sorghum are cultivated. Likewise, communities often integrate usage of wetland and dryland areas, utilising crops that require labour at different times of year, as is the case in Sierra Leone, where communities have 'one foots in the wetland and another in the dry'(Adams, 1993).

From this list of usages it is clear these wetland areas play a crucial role as an ecosystem service. This is supported with the outputs from this various ecosystems having been valued. For example in Kilombero Valley in south-western Tanzania, the areas wetlands were calculated to provide up to 66% of the average households US$ 518 income, accounting for a significantly larger portion in poor households. Furthermore, this is without even accounting for consumed staple crops. Similarly, the overall economic output from the Hadejia-Nguru wetlands in north-eastern Nigeria has been valued at US$37 million per annum, equating to $51 per hectare and $13,000 per metre cubed of water (Barbier, 1993). 

Although these values provide an insight into the incredible economic and developmental significance the wetlands play in Africa, they also demonstrate some issues. These valuations are based solely on agricultural, fuel-wood and fisheries benefits, and as alluded to earlier, many other important aspects for valuation are ignored. This suggests the flaws and limitations of these ecosystem service valuations, especially as they can have stark impacts on informing policy on sustainable utilisation of these resources. These are important issues, which can have telling impacts on wetlands management, and are something which I will come back to in my next blog!

Ecosystem Services and the Distribution of Water in Africa

Ecosystem Services and the Distribution of Water in Africa

Before attempting to dive into discussion of the complexities of ecosystem services it is important to briefly outline the wider context they are being discussed in. Thus this second blog will involve little direct discussion of Ecosystem Services, but look at one of the major factors effecting water availability in Africa, variation in precipitation. This will involve mostly outlining of climatic factors, as well as some limited discussion of other factors which impact distribution of water and it's availability.

The context of water management in is Africa very different to almost every other context, with the only similar example perhaps being from Australia, due to the huge variability in distribution over both time and space across the continent. This variation is predominantly controlled by levels of precipitation, with climatic impacts of this ‘superimposed upon regional factors’ (Nicholson, 1996) of temperature, evapo-transpiration, topography and soil structures in Africa which impact the distribution of water once it has been released as precipitation (UNEP, 2010). 

Levels of precipitation are obviously incredibly important for Ecosystem Services, with water essential for driving all ecosystems, whether they directly or indirectly provide services for human consumption.

Determinants of Precipitation Levels Across Africa

The main climatic driver of water distribution in Africa is the ITCZ, or the Inter-Tropical Convergence Zone. This is a function of Hadley Cells, the formation of which is a cyclical process, but can be seen as beginning where insolation is highest, at the thermal equator or the ‘latitude of the maximum surface heating’ (Hu, et al., 2007). This can be split into several phases:

1. At the thermal equator air is warmed and rises through convection, creating low pressure.
2. This causes air to flow in to replace it, with these flows known as the trade winds. This replacement air is subsequently heated, continuing the process.
3. The heated air rises and cools, shedding accumulated moisture as precipitation.
4. This elevated air then begins moving pole-wards, away from the equator.
5. Meanwhile cooling continues, eventually causing descent, and condensation, and so significantly less precipitation occurs where this occurs.
6. The resultant pressure difference then causes the air to flow back towards the Equator.

Annual Water Balance, Source-UNEP, 2010

The ITCZ is the point of convergence of inter-hemisphere trade winds between the two Hadley cells either side of the equator, and through the above process has a clear impact on levels of precipitation.

Therefore rainfall is generally highest near to the equator, with levels of precipitation reducing towards the poles, both north and southwards away from the ITCZ. 

The impact of this is evident in the annual water balance diagram from the United Nations Environment Program and from Ziegler et al.. This highlights the impact the ITCZ and precipitation has on overall water availability across Africa (UNEP, 2010). The large rainfall surplus across the majority of central Africa clearly illustrates the impact of the ITCZ in increasing rainfall within these regions.

Although the ITCZ does play a crucial role, there are other sources of rainfall, such as orographic rainfall influenced by local topography, as well as from maritime sources of rainfall.

Furthermore although water surpluses do mirror rainfall, it is important to note that there are impacts beyond this that impact access to water. These include the impact of evapo-transpiration, which can remove up to 90% of rainfall. Similarly, it can also be influenced by local geology, with some areas having higher filtration rates meaning water feeds into groundwater and aquifers rather than surface sources. This can have significant impacts, particularly when working in tandem with tectonics, as evidenced by the impact of rift valleys in East Africa. This has led to the formation of narrow and deep lakes, with limited surface areas reducing the impacts of high seasonal evapo-transpiration.

Nonetheless, levels of precipitation play a central role in determining the availability of water across Africa's ecosystems and their services. As evidenced by the stark impact that another aspect of the ITCZ has on African water availability.

Wet Hot African Summer

The ITCZ is more than simply a determinant of spatial distribution of water, and it also has a stark temporal impact. This is due to the  location of the ITCZ varying seasonally, impacted by shifts in the thermal equator resultant from the changing relative locations of the Sun and the Earth. This causes the ITCZ to oscillate between 20 degrees north and south of the Equator, as shown in the diagram below. Subsequently the rainfall impacts to follow, and thus a significant variation in levels of rainfall in areas at the outer limits of it's reach.This results in a Wet and Dry Season in some areas, with the northernmost extent of the ITCZ coming in August leading to a wet season across the Sahelian regions then, with the mirrored impact south of the equator coming in January. 

Seasonal Oscillation of the ITCZ, Source-Ziegler et al, 2013

This shift causes massive variation in rainfall, with very few days of rainfall per month in the dry season, whilst in contrast in the wet season rainfall can be daily. This leads to variation in rainfall from as high as  These shifts have a massive impact on the seasonal distribution of precipitation, leading to massive peaks in some areas, with the vast majority of some regions rainfall occurring in the space of a few weeks or months.
This has a massive impact on the seasonal the availability of water, with African rivers some of the most seasonally variable in the world, having the highest co-efficients of variation in river discharge.

This availability is incredibly important in supporting ecosystems services in Africa, and has given rise to specific ecosystems, coping strategies and problems. The impacts and importance of these for ecosystem services will be highlighted in my next few blogs.