Rivers, lakes and wetlands are saturated with freshwater, either permanently or seasonally, creating unique habitats for a variety of aquatic plants and animals. These ecosystems are typically characterized by vegetation adapted to waterlogged, oxygen-poor soils, and can include marshes, swamps, and bogs. Freshwater wetlands are especially valuable for their role in filtering water, reducing flood impacts, and providing habitat for biodiversity.
In the Nordics, rivers, lakes and wetlands are diverse and ecologically significant, playing a crucial role in supporting biodiversity, regulating water flow, and sequestering carbon. Wetlands in the Nordics range from small streams, over large lakes to peatlands, and they are integral to the region's natural landscape and cultural heritage. As such, wetlands are also an important ecosystem in agricultural systems, which are dependent on water availability and are also often the source of degradation of these ecosystems. Some of the main types of wetlands are:
Peatlands - bogs: Common across the Nordic region, especially in Finland and Sweden. Bogs are acidic, nutrient-poor wetlands dominated by sphagnum mosses. They often form in cool, humid climates and accumulate thick layers of peat.
Peatlands - fens: Found throughout the Nordics, fens are less acidic and more nutrient-rich than bogs. They are often fed by groundwater and support a diverse array of plant life, including sedges, grasses, and various flowering plants.
Marsh: A marsh is a type of wetland that is dominated by herbaceous plants rather than woody vegetation like trees and shrubs. It typically has shallow, standing or slow-moving freshwater or brackish water and is characterized by waterlogged, nutrient-rich soils. These wetlands often occur along the edges of rivers, lakes, and estuaries, serving as transition zones between aquatic and terrestrial ecosystems.
Shallow Lakes and Ponds: The Nordic region is dotted with thousands of lakes and ponds, many of which are surrounded by wetland areas. These water bodies support a variety of aquatic life and are important for migrating birds and amphibians, for example.
Riverine/ floodplain wetlands: These wetlands are found along rivers, particularly in Sweden and Finland. They play a crucial role in flood management and provide habitats for species like beavers, otters, and a wide range of birds.
Forested Wetlands/ swamps: Forested wetlands, particularly those dominated by pine or spruce, are common in the Nordic countries. These swamps often occur in conjunction with peatlands and are important for species like moose and various bird species.
Nature-based Solutions in wetlands address a range of societal challenges by using the inherent capabilities of these systems. Some of the main societal challenges that can be effectively addressed by applying NbS in rivers, lakes and wetlands are:
Disaster risk and preparedness (flood risk management) - One major challenge is that there is an increasing frequency and intensity of floods due to climate change and urbanization. Restoring or creating wetlands, such as floodplains and marshes, helps absorb and slow down floodwaters, reducing the risk and severity of floods in downstream areas.
Water Management (improvement of water quality) - Pollution and nutrient runoff from agricultural and urban areas degrading water quality. Wetlands act as natural filters, trapping sediments, nutrients, and pollutants. Restoration of wetlands helps improve water quality by reducing the load of contaminants entering rivers and lakes.
Biodiversity enhancement (biodiversity loss) - Habitat destruction and fragmentation lead to declines in species populations and loss of biodiversity. Wetlands provide critical habitats for a diverse array of species. By protecting, restoring, or creating wetlands, biodiversity can be enhanced by supporting the survival of both aquatic and terrestrial species.
Climate Change Mitigation - Rising greenhouse gas emissions contribute to global warming. Wetlands, especially peatlands, are significant carbon sinks. By preserving and restoring these areas, it is possible to sequester large amounts of carbon dioxide, helping to mitigate climate change. By preserving and restoring these areas, we slow down the decomposition of organic matter and halt the release of carbon dioxide. This prevents further loss of carbon stored in the soil. Furthermore, it is possible to sequester large amounts of carbon dioxide, helping to mitigate climate change.
Climate Change Adaptation - Increasing temperature and changing precipitation patterns affecting communities and ecosystems. Wetlands can help communities adapt to climate change by providing natural buffers against extreme weather events, stabilizing local climates, and maintaining water availability during dry periods.
Rivers, lakes and wetlands before NbS have been implemented
Rivers, lakes and wetlands after NbS have been implemented
Modify river cross section by re-meandering: A previously straightened or channelized stream is returned to a more natural, meandering (curving) planform.
Raise riverbed levels: The stream bed level of a previously cut down stream is elevated to reconnect the river with the surrounding area.
Ditch and drain blocking and filling: Man-made drainage ditches and drains that were originally constructed to lower the water table for purposes like agriculture are obstructed or filled completely.
Disconnect functioning drainpipes: Artificial drainage systems are disconnected to prevent the water from entering directly into the stream.
Rewetting: Former wetlands that have been drained for human activities are rewetted applying different types of NbS that restore the natural hydrology of the area
Floodplain reconnection: Floodplain can be reconnected to its surrounding by applying different types of NbS that reconnect the hydrological connectivity between the river and the floodplain.
(Re-)establishment of shallow lakes and ponds: Small, shallow bodies of water are created in areas where they have been lost, degraded, or were not previously present.
Are you unsure how to choose an NbS for a wetland ecosystem? See our general guidance on Nature-based solutions!
You may also be interested in the S-ITUATION project's factsheet on wetlands, which describes types of NbS that are typically used to solve various problems in specific land-use contexts.
These pages have been written by Annette Baattrup-Pedersen.