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World Wetlands Day: resisting extreme natural events

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Every year on February 2nd, the whole planet celebrates wetlands: The 2017 edition of World Wetlands Day is dedicated to the role of these exceptional territories in disaster prevention. As every year on the same date since 2001, French citizens will be made aware of the richness and functionality of these exceptional ecosystems, and committed to their protection. A brief look back at the role of these areas that are essential to our survival.
In recent decades, the frequency of natural disasters has more than doubled worldwide. While climate change is implicated in this phenomenon, the destruction of natural ecosystems - especially wetlands - by human activities greatly aggravates the consequences.
Indeed, wetlands often act more effectively than infrastructure construction in mitigating the damage caused by extreme weather events. In the face of these growing threats, today more than ever we must preserve and rehabilitate these natural environments.
ALLAIN BOUGRAIN DUBOURG, Chairman of the LPO
VÉRONIQUE PENCHIENATI, Executive Director Evian Volvic Monde
MARTHA ROJAS-URREGO, Secretary General of the Ramsar General Convention 

Indispensable sources of life for mankind

Wetlands are among the most diverse and productive ecosystems. They provide us with essential services: food reservoirs, water purification, flood prevention, tourism, biodiversity conservation and many others. However, they continue to be degraded and transformed by human activities, sometimes to the point of destruction.
The Ramsar Intergovernmental Treaty (1)The World Heritage Convention, signed in 1971 under the aegis of UNESCO, has as its mission the protection and wise use of wetlands and their resources. By signing the Convention, member countries commit themselves to protect their wetlands of international importance and to implement sustainable management. Today more than 2,200 wetlands are inscribed on the Ramsar List, including 44 sites in France.
 

Marshes, bogs, wet meadows, lagoons, mangroves, deltas, bays, lake and river banks, wetlands are home to a multitude of interacting plant and animal species. They play a major role in providing many services to humanity: they recharge groundwater, purify surface water, and absorb and mitigate floods and droughts.
Wetlands protect banks and shorelines from erosion, and coastlines from storms. 50% species of birds living in France depend on these environments. 30% of remarkable plant species are dependent on them. As repositories of cultural values, these living lands are pivots of economic development.
 
The studies of Australian researcher Nick C. Davidson show that 64% of wetlands have disappeared since 1900, limiting access to fresh water for more than a billion people. Since 1970, dewatering has led to the loss of 76% of freshwater species populations. In the future, the complete disappearance of these areas would lead to significant climate change since, in addition to no longer absorbing precipitation and no longer fixing the coastline, wetlands would release a significant amount of carbon: Professor Christian Blodau estimates, for example, that peat bogs retain 30% of the carbon stored in the terrestrial environment.
 
Today, wetlands are undergoing major upheavals due in particular to: land use, the expansion of intensive agriculture, timber exploitation, water diversion by dams, dykes and pipes, air and water pollution, etc., and also disasters (floods, droughts, heat waves, land subsidence, storms, etc.) which it is imperative to prevent in order to better protect these living environments.
 

For disaster prevention

The 2017 edition of World Wetlands Day is dedicated to the role of wetlands in disaster reduction.
Indeed, these environments protect human populations from a wide variety of natural disasters (flooding, marine submersion, drought...), including those aggravated by climate change. These wetlands thus strengthen the resilience of territories, like real free natural infrastructures.
Inland, ponds, marshes, bogs, riparian areas, etc. act as buffers and sponges by slowing and absorbing water, reducing both floods and droughts by recharging groundwater tables with water. Then, during summer heat waves, urban wetlands help cool the air by evaporating water from their soils, reservoirs and vegetation.
Moreover, their good hydraulic operation avoids the unfortunate effects of costly land subsidence and, to a lesser extent, forest and peat fires.
On the coastline, mudflats, salt meadows, lagoons, coral reefs, mangroves and other salt marshes protect the coast from wave action, erosion, sea-level rise and marine submersion as natural attenuation and ramparts, combining the protection of infrastructures and populations with the wonders of their landscapes and the leisure activities these environments offer, which cannot be achieved by dykes and riprap.
For example, in 2012, Hurricane Sandy ravaged the American coasts, causing 210 deaths, some 20 missing and $52.5 billion in damage. It was the second most costly hurricane for the USA after Katrina in 2005, following which the US Congress decided to restore coastal wetlands at a cost of $460 million. Without the coastal wetlands, the costs would have been 10 % higher.
 

This is why, as many of the disasters are expected to increase in frequency and intensity due to climate change, wetlands can be designated as climatic shock absorbers of the causes (carbon storage in peat bogs, seagrass beds, coral reefs...) as well as the effects of this global change.
 
 
Wet meadows in the face of floods
 
In the case of floods, wetlands such as floodplains and wet meadows serve as natural reservoirs for flood expansion. The overflow of rivers in peripheral wetlands (ponds, dead arms of rivers, etc.) and the retention of water thus cause a decrease in flow and a spreading over time of the maximum water flow, and thus of the floods. In addition, the vegetation in these environments and the sediments dissipate the hydraulic energy, reducing the flow velocity. These two effects thus reduce the magnitude of the phenomenon in the event of flooding and the risk of flooding.
As an example, the conservation of the alluvial plain of the Bassée, a natural infrastructure upstream of Paris (flood expansion zone of the Seine), generates a flood-control service evaluated between 2 and 37 million euros per yearc and avoids building a dam which would cost between 100 and 300 million euros and which would not pay for the other services provided by this environment (water treatment, fishing, etc.).
Protecting and restoring alluvial wetlands means protecting cities and activities. from the raging waves.
 
Marshes and ponds to reduce drought and heat waves
 
The absorption of water in winter and during flood events allows wetlands to supply water to aquifers and streams. As such, they contribute to the supply of water for human consumption and the needs of agricultural and industrial activities. Some wetlands can store up to 15 000 m3 of water per hectare and one counts for example 46 million cubic metres of water which recharges the water tables every year on the territory of the regional natural park of the Cotentin and Bessine marshes.
In addition, water evaporation and evapotranspiration from wetland vegetation in urban areas help to cool the air, locally reducing the intensity of heat waves. Some "heat wave plans" take this into account, such as the project to redevelop the banks of the Rhône in Lyon following the 2003 heat wavef. For its part, the Seine-Saint-Denis department is implementing a rainwater management policy with storage and infiltration in temporary urban wetlands to cool cities (and fight against flooding).
Conserving and recreating wetlands in the city and the countryside means less discomfort during heat waves and droughts.
 
Moisture to prevent soil compaction
 
When clay or peaty wetlands are no longer sufficiently supplied with water, withdrawals are too high and/or drought occurs, the soil settles, weakening the buildings. The cost of repairs in the event of a disaster is then on average €15,000 per building, but can amount to the total price of the building.
In addition, climate change will increase this type of disaster. An increase in damage of 50 % has already been observed over the period 1987-2006 compared to the period 1950-1970, and another increase of 50 % is predicted for 2021-2040.
The solution to avoid these settlements and destruction lies in soft methods of infiltration of rainwater, such as gullies, ponds, dry rivers and other temporary wetlands ... as can be seen on the LyonTech ecocampus la Doua or in the ZAC des Ruires d'Eybens.
Protecting the hydraulic operation of wetlands means protecting the frame.
 
Salt marshes, lagoons and mangroves against waves and storms
 
On the coastline, wetland vegetation such as mudflats, mangroves or salt marshes forms a natural barrier and mitigates the effects of waves and wind, stabilizes sediments, thus combating erosion and the risk of barrier beach breakage.
For example, it was found that salt marsh vegetation reduced wave heights three times more than nuk sands. Thus in 2012, in the USA, coastal wetlands reduced the cost of damage from Hurricane Sandy by 10 %, or $625 million. A study showed that coastal wetlands, when still present, reduced storm damage costs by 20 %.
In England, the Medmerry (West Sussex) estuary reclamation has naturally recreated salt marshes and protected the area from damage during the winter of 2013-2014, compared to 6 million pounds of damage in 2008 under the same weather conditions.
Also across the Channel, the breaching of three breaches in the Freiston Shore (Lincolnshire) breakwater and the restoration of the coastal wetland behind it have increased coastal protection against flooding and created a site of major biodiversity interest, with economic benefits through tourism.
In tropical regions, mangroves reduce the height of tidal waves by 5 to 50 cm per kilometre of mangrove width. These environments also reduce wave heights by 75 % for every kilometre of mangrove covered.
For the same reason, Thailand is restoring mangroves in the Krabi estuary, with an estimated 309,600 $/year of coastal protection.
Coral reefs, which are also considered wetlands under the Ramsar Convention, are not to be outdone. For example, the coral reefs off the coast of Sri Lanka, protected by a marine park, prevented the 2004 tsunami from causing damage beyond 50 m inland, while in neighbouring areas where coral mining degraded the reefs, the tsunami caused damage up to 1.5 km inland.
Finally, in France, the Ad'Apto project launched in 2015 by the Conservatoire du Littoral (Coastal Conservatory) aims to show in a concrete way, through local examples of adaptation to the hazards of erosion or marine submersion, that a reasoned anticipation accepting the mobility of the land-sea interface on preserved natural spaces is possible.
Conserving coastal wetlands means protecting them from waves, erosion and marine submersion.

World Day 2 February 2017

The launch day will be held in Brouage in Charente-Maritime on Thursday 2 February with a press breakfast and two round tables on the role of wetlands in disaster prevention and wetland management in French-speaking countries.
 
This 2 February, the anniversary of the Ramsar Convention, will therefore be an opportunity to present to the public and stakeholders in our territories "their" wetlands or those in the surrounding area, through a field visit, an exhibition, a tale or a debate. Thus, from 28 January to 28 February 2017, associations, natural area managers, education or documentation centres and local authorities will be presenting the richness and roles of these environments.

In 2016, more than 120 events were proposed from the end of January to the end of February and 2340 people participated!
 
Some key LPO animations on the menu of this 2017 edition :
 
- LPO Alsace proposes to leave on January 29th on board a cruise ship with experienced ornithologists, to discover the wintering birds that come to spend the bad season on the Rhine, a wintering area in France.
- The LPO Auvergne proposes a Wetlands Rando on February 11th around Loudes. Accessible to all, the discovery of the Collange marsh will allow to approach the interest of this area for its biodiversity.
- The LPO Haute-Savoie invites nature lovers or those curious about nature to come and discover the wintering birds of the Dranse Delta Nature Reserve on 5 February, as well as the essential role played by wetlands for the wintering of water birds.
- The LPO Vienne and its ornithological guides will take you to meet the birds of Saint-Cyr on the occasion of the Lake Saint-Cyr Bird Festival on Sunday 5 February.
- The LPO Brenne proposes to discover the birds of the ponds of La Touche but also the other protected endemic animals and plants. The outing will take place on February 3 from an observatory usually closed to the public, in the company of the site's curator.
 
The Ramsar France association (2), Onema, the Pôles-relais zones humides, the LPO and the Société nationale de protection de la nature, coordinate all of the activities carried out in France.
 
Photo contest organized by Ramsar
 
On the occasion of World Wetlands Day, the Secretariat of Ramsar, the international convention for the protection of wetlands, is organizing a photo competition for young people between the ages of 18 and 25. From 2 February to 2 March, try to win a trip offered by Star Alliance Biosphere Connections to the Ramsar Site of your choice! To do so, take a photo of a wetland that protects us from disasters and go to http://www.worldwetlandsday.org/fr
 
(1)    For more than 40 years, the Ramsar Convention has been working to protect the world's wetlands. This intergovernmental treaty, signed by 160 countries, aims to protect, conserve and make wise use of wetlands through strong international cooperation, but also through national, regional and local actions that contribute to the sustainable development and integrated management of our planet's natural resources. To date, the Ramsar List of Wetlands of International Importance includes just over 2200 classified wetlands worldwide, including 44 in France, which are remarkable sites for the fundamental ecological services they provide and for their fabulous biodiversity.

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