Wetlands and their role in biodiversity
These ecosystems are home to a wide variety of animal and plant species—many of which are unique—that depend on these habitats for reproduction, food, and survival. They also serve as stopover sites for many migratory birds and as refuges for endangered species.
“Natural sponges” that protect against flooding
Contrary to popular belief, wetlands do not cause flooding; they help prevent it. When there is heavy rainfall, these areas act like sponges: they absorb excess water and release it slowly, thereby reducing the risk of flash floods. For example, marshes can store millions of liters of water, preventing towns and fields from being flooded.
A key role in the fight against climate change
Wetlands are carbon sinks. This means they capture and store carbon dioxide (CO₂), one of the main gases responsible for global warming. Peatlands, for example, contain more carbon than all the world’s forests combined. But if these areas are destroyed, that carbon is released into the atmosphere, further exacerbating climate change.
A natural water filter
These ecosystems purify water. The plants and soil in wetlands trap pollutants (such as pesticides, nitrates, and heavy metals) and help clean the water before it flows into rivers or groundwater.
Sanctuaries for biodiversity
Wetlands are home to an incredible diversity of species: migratory birds, amphibians, insects, fish, rare plants… These habitats are essential breeding and feeding grounds for thousands of animals.
The impacts of human activities and climate change
Unfortunately, wetlands have been disappearing at an alarming rate for decades. In France, more than 60% of them have disappeared since the 20th century*, and here’s why:
Land drainage
Humans have drained wetlands to make room for agriculture, build roads, or construct homes. This is done by digging ditches or installing drainage systems to remove water. For example, in rural areas, many ditches along roads—which used to serve as water storage—have been filled in.
Urbanization
Many wetlands have been paved over to make way for cities, parking lots, or industrial zones. This has destroyed the soil’s ability to retain water, exacerbating flooding in built-up areas.
Pollution
Pesticides and fertilizers used in agriculture end up in wetlands, poisoning plants and animals. Industrial and urban waste has also contaminated these fragile ecosystems.
Climate change
With more frequent droughts and rainfall that is sometimes too intense, wetlands are becoming increasingly vulnerable.
How can we protect wetlands?
Faced with their decline, everyone can contribute to the preservation of wetlands, whether through individual, local, or global actions. In France, programs such as the ‘Ramsar sites’ play a key role in their conservation. [Designation as a Ramsar site is an international recognition granted to the world’s most important wetlands.] It is also possible to limit construction or development projects that destroy these environments (roads, parking lots, etc.) and to restore degraded wetlands. In some cases, dried‑out areas can be rehabilitated by recreating ditches or ponds, replanting local plant species that help re‑establish natural balance, and reducing pollution. Agricultural practices that respect natural water cycles and limit excessive land drainage can also be encouraged, as well as maintaining floodplain meadows that support biodiversity and retain water.
Raising public awareness and organizing educational field trips to explore these unique ecosystems are also key drivers of change! By educating future generations and engaging local communities, we can reverse the trend and restore the vital role that wetlands play for our planet.
Two educational activities to explore and protect wetlands (Grades 4–6)
Why do wetlands help prevent flooding?
Objective: To understand the role of the “natural sponge.”
Materials: Two large containers (one with dry sand, the other with wet sand and plants), a watering can.
Procedure
The students pour water into the dry sandbox: the water runs off quickly, overflows, and floods the floor. Then they sprinkle the sandbox with damp sand and plants: the water is absorbed more slowly.
Conclusion
Wetlands absorb water like a sponge and prevent sudden flooding.
Draw and protect your wetland with our aquatic Ecomap
Objective: To explore biodiversity and consider concrete steps to protect these habitats.
Procedure
Students draw an ideal wetland on the Ecomap, including the necessary plants, animals, and natural features (reeds, frogs, birds, fish, etc.). Then, in groups, they discuss potential threats (pollution, roads, drought) and ways to protect the wetland (cleaning up trash, planting vegetation, creating protected areas). The ideas are then shared with the class to draft a “wetland protection plan.”
These activities combine observation, experimentation, and civic engagement to raise students’ awareness of the importance of these ecosystems.
Sources: French Office for Biodiversity (OFB) and the Ministry of Agriculture and Food Sovereignty”*