African Wildlife and Environment Issue 66

CONSERVATION

CONSERVATION

Engineered wetlands Our knowledge of the benefits that wetlands bring to society is best illustrated by the East Calcutta Wetland system. This vast and ecologically complex system is significant, because it maps out our future based on human ingenuity of the past. The name was given by Dr DhrubajyotiGhosh in his capacity as Special Advisor to the IUCN. These water bodies provide natural sewage treatment capacity for the city of Calcutta in West Bengal. Today it is host to the largest sewage fed aquaculture project in the world. Of such significance are the ecosystem services provided to humankind that this wetland was designated a Ramsar site in 2002, even though it is largely man-made. The South African equivalent is also a semi-man made system, centred on the Blesbokspruit. This is a small natural wetland that has grown massively over a century, because it receives the water abstracted from underground workings in the Eastern Basin of the Witwatersrand Goldfields. This has also been designated a Ramsar site, but it has not been studied as much as the East Calcutta Wetland. More importantly, the process of natural selection has seen the emergence of a range of bacteria, archaea, fungi, algae, protozoa and protists as a result of mutation in the presence of man-made chemicals flowing through engineered wetland systems such as in East Calcutta. Pioneering research has been done by Indian scientists in mapping the presence of new strains of microbe with both ecological and commercial significance. These discoveries include a sub-set of Actinobacteria capable of metabolizing a range of industrial compounds, including nitrophenol, nitroaromatic compounds, pesticides and herbicides. A sub-set of Proteobacteria are believed to be central to our growing understanding of bioremediation of heavy metal or oil contaminated soil. If we had to apply the same level of diligence to the Blesbokspruit, we would probably find a sub set of mutated microflorae or archaea capable of metabolizing sulphur rich acidic mine water and the range of metals dissolved therein. Conversely, if we studied the Wonderfonteinspruit wetlands, not designated a Ramsar site, but draining an area with a known plume of uranium contamination, then we would probably find extremophiles capable of metabolizing this specific metal (and all daughter by products of uranium decay). These ideas are of great significance to South Africa, particularly where heavy metal contamination plumes are moving through aquatic ecosystems as a result of 120 years of largely self-regulated mining in the absence of effective democratic oversight. They are even more significant in a new world where climate change seems to be exacerbating natural drought cycles.

This global problem is more acute in Southern Africa, where we are blessed with a generally arid climate. Aridity means that more water is lost to a combination of evaporation and transpiration (technically known as evapotranspiration - abbreviated as ET) than falls as natural precipitation. In South Africa, this is starkly evident in the Vaal Dam situation where more water is lost from storage to ET, than flows in under natural hydrological conditions for eleven months of the year. Wetlands in context Wetlands play a crucial role in the biophysical processes of any natural aquatic ecosystem. The problem is that as population growth outstrips the capacity of natural aquatic ecosystems to function, then pressure on natural wetlands rises. The human species is now confronting a stark choice: either adapt or face the dire consequences of human-induced water scarcity. The United Nations does its best to play a leadership role in shaping policy of its member states. One of the ways this is done is via the World Water Assessment Programme (WWAP) that tables reports at regular intervals. The most recent was a report entitled ‘Wastewater – the Untapped Resource’, which identified the future as increasingly being focussed on recovery and recycling of potable water from waste streams. In South Africa, we could potentially recover five billion litres daily from this approach. This is an extremely important policy direction for any water constrained country to consider. It lies central to our future national wellbeing, because the South African economy is now fundamentally water constrained. This has dire consequences for job creation, and is central to any notion of social cohesion, political stability and investor confidence. The next iteration of the WWAP is currently in an advanced stage of preparation before being made public. One key element of this report is the concept of ‘nature-based solutions’ (NBS). Stated simplistically, this notion underpins the stark choice that humans have as a species: either engineer solutions in partnership with Nature, or face the consequences of engineering solutions that compete with Nature. Wetlands fall into this category, with two broad dimensions that will increasingly become mainstream in terms of both policy and practice. The first dimension is centred on the need to protect existing wetlands and rehabilitate those that have been adversely affected by human activities. The second dimension is likely to emerge as an entirely novel model of economic development, because it is centred on the notion of engineered wetlands.

Evolution of wetlands as key elements of nature-based SOLUTIONS IN THE WATER SECTOR

It is a simple fact that the world is running out of freshwater. This is driven by population growth and exacerbated by climate change, irrespective of whether it is human-induced or not. The stark irony is that at planetary level we are water abundant, but 97.5% of the total volume of water is saline. Of the remaining 2.5% that is fresh, a paltry 0.3% is found in lakes and rivers. These are simple facts that our species cannot ignore if we wish to continue living in stable economies with reasonably predictable levels of social cohesion and modern creature comforts.

Prof Anthony Turton

A World of Salt Total Global Saltwater and Freshwater Estimates

0.3% 30.8%

Lakes and river storage Groundwater, including soil moisture, swamp water and permafrost Glaciers and permanent snow cover

Freshwater 2.5% 35 000 000 km 3

68.9%

Saltwater 97..5% 1 365 000 000 km 3

Scientific and Cultural Organisation (UNESCO, Paris), 1999.

Source: Igor A. Shiklomanov, State Hydrological Institute (SHI, St. Petersburg) and United Nations Educational,

Planet Earth has an abundance of water, but 97.5% of that is saline and thus unsuitable for human consumption. (Source: UNESCO).

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9 | African Wildlife & Environment | 66 (2017)