World Water Day 2015: MARS, Ecosystem Services and Sustainable Development

On Sunday March 22nd, people from around the world will get together to mark World Water Day 2015.  Organised by the UN-Water programme and now in its 22nd year, World Water Day is designed to focus attention on global water issues, and to celebrate the role of water in all of our lives.

This year, the theme is “Water and Sustainable Development“.  The World Water Day website describes how water is often unsustainably used and managed around the world because the essential services provided by freshwater ecosystems are not recognised or valued by the economic models that structure policy and land use decision-making processes.

The MARS project works to understand the impacts of multiple stressors (pollution, abstraction, drought, dams and so on) on freshwater ecosystems.  So how might MARS’s work relate to the theme of sustainable development?  I spoke to MARS scientist Sebastian Birk to find out more.

Sebastian suggested, “MARS and Sustainable Development can be linked via the provision of ecosystem services generated from freshwater systems. MARS distinguishes between an ecosystem’s service capacity (i.e. what the multiply stressed ecosystems can provide) and service flow (i.e. what humans are taking from these ecosystems).

The service capacity is related to the conditions (i.e. state) of the ecosystem, depending on the amount of pressure exerted to these systems. The service flow is related to human behaviour (steered through legal requirements such as the Water Framework Directive).

The ratio between service capacity and service flow is an indicator for sustainability: services should not be taken above a level that can be sustainably provided. The measures we’re analysing in MARS to mitigate the effects of multiple stressors shall ultimately lead to a sustainable service use.”

So, the idea is relatively straightforward: an ecosystem can provide certain services (drinking water, fish for consumption and so on), that if managed sustainably will continue to regenerate and be provided in the future, but will be threatened if over-harvested, mismanaged or polluted.  As an example, the World Water Day website cites the Okavango River basin in south-west Africa, a river which has been largely unaltered by humans until now, but is increasingly exposed to pollution from untreated residential and industrial wastewater and agricultural run-off and subject to abstraction for water supplies.  This pollution and abstraction potentially undermines the river’s capacity to provide ecosystem services to surrounding communities, and threatens its ecological health and diversity.

For the World Water Day organisers, the solution to such problems is to better integrate the value of ecosystem services into economic models.  They suggest that, “Economic arguments can make the preservation of ecosystems relevant to decision-makers and planners. Ecosystem valuation demonstrates that benefits far exceed costs of water-related investments in ecosystem conservation. Valuation is also important in assessing trade-offs in ecosystem conservation, and can be used to better inform development plans. Adoption of ‘ecosystem-based management’ is key to ensuring water long-term sustainability.”

But just how easy is it to fully quantify all of the services provided by an ecosystem (Sebastian Birk’s ‘service capacity’) and the services that are used by humans (the ‘service flow’)?  Complicated, but potentially possible, is the answer.  A 2014 paper by Matthias Schröter from Wageningen University, Netherlands and colleagues, attempted to the provision and use of nine ecosystem services (moose hunting, sheep grazing, timber harvest, forest carbon sequestration and storage, snow slide prevention, recreational residential amenity, recreational hiking and existence of areas without technical interference) in Telemark County in Southern Norway.

Using large datasets of environmental data, through which indicators for ecosystem services were identified, Schröter and colleagues concluded that a key factor in modelling the relationship between service provision and use is in matching their spatial extent.  They suggest that some ecosystem services, particularly cultural services – recreation, spiritual value and so on – are often very local and heterogeneous and so more difficult to integrate into such an analysis.

Regardless of the different economic or statistical approaches we might take to understanding and modelling sustainable development and water, perhaps it is apt to reflect back on a basic tenet of sustainability: to refrain from taking more from an ecosystem than it can provide.  Here, we might also ponder the words of the great conservationist Aldo Leopold when planning our freshwater decision-making.  In A Sand County Almanac, Leopold wrote that “A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise.”

How can we best encourage sustainable development that doesn’t compromise the “integrity, stability and beauty” of our freshwater systems?  Are ecosystem services the best framework for providing a ‘voice’ for the natural world in decision-making?  Please feel free to add your voice to the debate, either in the comment box below, or through our Twitter page.