River ecosystems encompass river channels and its floodplains and form a diverse mosaic of habitats with the riparian area at the transition zone between the land and water. During flood events, water and sediment are transported onto the floodplain and provide the nutrients that render river ecosystems highly productive. Conversely, floodplains (and other wetlands) constitute important sinks of river nutrients and sediments and, hence, contribute substantially to a river’s self-purification. They act as a sponge and regulate the water volume, as they cut off flood peaks and release water during low-flow conditions. Floodplains, especially the riparian areas, provide the river channel with carbon (organic matter) which is essential for sustaining riverine plant, animal and micro-organism communities in many regions of Europe.
Looking more precisely at the specific services provided by river ecosystems, their important role for human well-being becomes obvious. Nearly everywhere on Earth, people depend on rivers for fresh water supply and sanitation purposes. But there are many more services linked with rivers and floodplains besides these fundamental human needs. This schematic provides an overview of the major provisioning (e.g. fresh water and timber supply), regulatory (e.g. water and erosion regulation, self-purification), cultural (recreation and ecotourism) and supporting (e.g. soil formation, nutrient and water cycling) services provided by freshwater ecosystems.
Major ecosystem services provided by rivers, riparian areas and floodplains/wetlands in Europe.
Ecosystem services are sometimes valued in monetary terms for use in policy- and decision-making. This is relatively straightforward for provisioning services such as water and timber supply where market values exist. However, it is more difficult and often controversial for many regulatory and supporting services for which the direct benefits to people are not as clear. Nevertheless, several studies have provided values for river and floodplain ecosystem services. The Danube floodplain and wetlands, especially their regulatory role as a nutrient sink, have been valued at 650 Million Euro per year (Gren et al. 1995). On a global scale, an annual total value of 4,879 Trillion US$ has been estimated for wetlands and 3,231 Trillion US$ for floodplains (including swamps) or, altogether, around 24 % of the total annual ecosystems services’ value on Earth (Costanza et al. 1997).
In agricultural landscapes, mixed riparian buffers composed of trees and grass strips can effectively retain sediment from surface run-off and nutrients from the upper groundwater layer (Dosskey 2001). Photo of River Nuthe in Brandenburg, Germany taken by Christian Feld.
Details of the scientific papers mentioned
Costanza, R., d’Arge, R., groot, R.d., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., O’Neill, R.V., Paruelo, J., Raskin, R.G., Sutton, P., & Belt, M.v.d. (1997). The value of the world’s ecosystem services and natural capital. Nature, 387, 253-260.
Dosskey, M.G. (2001) Toward quantifying water pollution abatement in response to installing buffers on crop land. Environmental Management, 28(5), 577-598.
Gren, I.-M., Groth, K.-H., & Sylvén, M. (1995). Economic values of Danube floodplains. Journal of Environmental Management, 45, 333-345.
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