Par I, Claude Villetaneuse, CC BY-SA 3.0,
Marshes are very rich ecosystems. They are home to a variety of animals, birds, fish, water crayfish etc. In addition, they host a very wide variety of plants. Their role in the carbon cycle is also important, about 0.1% of the carbon sequestered in the terrestrial area is found in marshes. There was a time when we humans exploited marshes, undoubtedly attracted by the great wealth of fauna and flora.
Some of these areas in France and elsewhere were exploited in the 18th century for market gardening and ‘hortillonnage’, that is to say the production of vegetables in marshy areas. From the beginning of the 19th century. Many governments have decided, over the years, to drain the marshes to create agricultural areas, or for construction. In terms of agricultural production, we replaced an ecologically rich, productive and diverse system with farms that are much less productive.
I've already talked about the importance of a diverse (and non-industrial!) diet and I've also talked about edible wild land plants. At the end of this article you will find a link to a database of edible marsh and riverbank plants. There are many ! You may already be familiar with water chestnuts or watercress. Maybe not the others but our ancestors, knew them and used them.
We are still very attached to farms, market gardening and vegetable gardens. However, here are some reasons that show us that it is perhaps time to re-imagine everything.
Wet and aquatic areas are more productive than terrestrial areas, 4 to 20 times more productive. Here's why:
Temperature buffering. Water has a thermal inertia, it cools and heats up slower than air. Plants that grow in water or on banks therefore benefit from a much more constant temperature than plants that grow on land.
Nutrient availability. In aquatic environments these nutrients are more bio-accessible and they are better dispersed than in terrestrial areas.
Water stress is not a problem for plants in marshes and aquatic environments. Except sometimes in case of long or severe drought.
The banks are a zone where earth, water and air meet. They therefore have the advantages of terrestrial zones and those of aquatic zones. This is why they are so productive.
There are plants that take root in the mud at the bottom of ponds and marshes, in shallow water. Their upper parts emerging from the water, the water mint is an example. Thanks to the buffering effect of water, the availability of nutrients and the absence of water stress, these plants are the most productive of all climatic zones.
When there is enough space, or if it is desired by my clients, I really like to install a pond in a vegetable garden. It is a great resource for wildlife, bees, dragonflies, other insects come to drink, toads and frogs settle there. Very quickly, we can see the ecosystem becoming more and more complex. In these ponds, I install edible aquatics. I also create a marshy area, banks and I install edible plants adapted to these conditions.
And here is the database run by Plants for a Future