World Wetlands Day celebrated annually on February 2
Celebrated annually on February 2nd, World Wetlands Day marks the anniversary of the 1971 Ramsar Convention, in the Iranian city of Ramsar on the shores of the Caspian Sea., also known as the Convention on Wetlands, an international treaty created to support the conservation and sustainable use of wetlands around the world. Currently, there are over 2,300 Ramsar sights, or Wetlands of International Importance, that have been designated worldwide – which is good news considering the sad state of our world’s wetlands.
Just as forests are called as the ‘lungs of the earth’, wetlands are the ‘kidneys’ that regulate water and filter waste from the landscape. The kidney comparison aside, wetlands are the primary sources of freshwater, buffers of floods and droughts, recycler of nutrients and chemicals, and inextricably intertwined with our culture and identity. These ubiquitous ecosystems usually throw up beautiful mental images – a picturesque river, a houseboat on a lake, fishing in a pond and more. They are the subject of poetry and songs, provide the backdrop of films and books and are sacred to many people. More directly, wetlands are a source of livelihood, food and home to biodiversity.
What exactly is a Wetland?
Wetlands, areas of transition between aquatic and terrestrial habitats that are either covered by or saturated with water for at least part of the year, exist in nearly every climate worldwide, on every continent except Antarctica. Sources of water for wetlands include groundwater from aquifers, seeps or springs, rainwater and runoff, floodwater from nearby rivers or lakes, and seawater inundation, as in the case of tidal salt marshes. Just about every landscape in California hosts some type of wetland. The coast, of course, has its tidally influenced salt marshes, while inland valleys and grasslands have vernal pools and floodplains. High in the mountains are wet meadows and fens, and even in the hottest, driest desert parts of the state, wetlands take the form of fan palm oases and springs.
Wetlands are generally grouped into three broad categories:
– Marshes
– Swamps
– Bogs
MarshesMarshes are essentially flooded grasslands, areas of saturated or flooded land dominated by grasses and aquatic plants. They may be tidally influenced, consisting of brackish or salt water, or inland freshwater marshes not influenced by the tide. Marshes are the main types of wetlands represented across California.
Tidal saltwater marshes are found along the coast, where they range in salinity from freshwater in the upper marsh to highly saline in the lower intertidal marsh. They typically support a thick mat of low-growing, salt-tolerant plants, many of which have special adaptations, like succulent leaves, to help them withstand harsh conditions.
Freshwater marshes occur in level, low-lying areas where water from precipitation and runoff accumulates, often along the shallow edges of lakes and ponds. Reedlike plants typify freshwater marshes, and common types found in California are rushes, tules, cattails and sedges.
Wet meadows, a type of freshwater marsh, are areas of grasses, sedges, rushes and wildflowers growing over poorly drained soil, often in forest clearings. They may be dry for much of the year, and hold standing water only during the wet season. Picturesque wet meadows abound in forest clearings in the Sierra Nevada. Wildlife thrives along the edges of meadows, at the interface between dense forest and open habitat. Wet meadows provide this crucial habitat, yet like other wetlands, wet meadows have been subjected to draining and filling in order to make them “productive.” In the Sierra, they have also been heavily grazed.
Vernal pools are something of a grassland specialty here in California, occurring over clay soil or hardpan on terraces around the valley as well as on the valley floor itself. These beautiful wetlands range in size from puddles to wide, shallow lakes and vary greatly from year to year. In wet years, pools fill and may even overflow, connecting to other pools via vernal swales to form a wetland complex. Vernal pools are the epitome of a seasonal wetland. In the early spring they create beautiful pools across a lush green landscape, each pool ringed with wildflowers. But come summer, the pools dry up, the grasses turn brown, and the clay soil turns to dust. No one would ever guess wetland habitat is found in the dry golden hills surrounding the valley.
The prairie potholes region of North America extends from central Canada through the northern Midwestern states. The potholes formed when chunks of buried glacial ice, remnants from the last ice age, melted, forming bowl-shaped depressions that filled with water. Some potholes fill with water seasonally while others are permanent. Over half of North America’s migratory waterfowl depend on prairie potholes for feeding and breeding, and yet the region has been highly altered through draining and conversion to agriculture and only 40-50% of prairie pothole wetlands remain intact.
Swamps:
Think of swamps as flooded forests, permanently saturated, or nearly so, and dominated by trees. The two main types of swamp found in North America are forested freshwater swamps, like the bottomland hardwood swamps and bayous found in the southern United States, and saltwater shrub swamps, such as the mangrove swamps of Florida.
Bogs and Fens:
While marshes and swamps are common in warm climates, bogs are typically found in the cold, northerly climes of North America and Europe, as well as at high elevations in mountains like California’s Sierra Nevada. Other names for these habitat types include moors in Europe, and muskegs in Canada.
Bogs and fens form as vegetation grows in a wet area, often encroaching into a shallow body of water until it is entirely covered with plants. As the plants die, plant matter builds up, year after year, forming a dense, spongy layer of partially decayed vegetation called peat. The differences between a bog and a fen are subtle. While bogs receive their water directly from precipitation, the source of water for fens is generally from runoff, drainage, or ground water. Peat bogs generally have very acidic, nutrient-poor soil that supports a unique vegetation type, while the soil of fens is more productive. Bogs in California are rare (there might be a few along the north coast) but a good example of a fen can be seen near Happy Isles in Yosemite Valley.
What do wetlands do? Why are they so important?
Wetlands are, without a doubt, one of the most valuable ecosystems on Earth. The extent of their functions are wide and multifaceted, but a few of their main functions, or ecosystem services, are as follows:
Surface water storage and ground water recharge:
Wetlands act as giant sponges, slowing water runoff after storms, soaking up excess water and holding onto it. They function as sinks for storing excess water which could otherwise cause flooding, and by preventing rapid runoff, the water stored in wetlands is able to slowly percolate back into the ground, replenishing aquifers. (At least, we think aquifers can be replenished. That’s another topic for another day!)
Erosion control:
Wetlands, particularly those along the coast, act as buffers against powerful storm surges, slowing and dissipating otherwise damaging waves and currents that have the ability to erode shorelines, even wash away entire beaches and coastal communities. Nowhere have I seen a better example of this than along the low-lying coastal communities around Charleston, South Carolina. We visited on a calm, summer day, but looking out over the grasses of the coastal salt marsh it was easy to see how acres and acres of dense vegetation protects an otherwise fragile and vulnerable coastline – built up with very expensive and beautiful houses!
Flood control:
Similar to the previous two functions, inland wetlands have the ability to absorb and trap huge amounts of water that seasonally overflows the banks of rivers and lakes. In California’s Central Valley, this was an important function of riparian wetlands, and wetlands surrounding the gargantuan – now extinct – Tulare Lake. As snow in the Sierra Nevada range melted and flowed down rivers into the Central Valley, those rivers flooded, and water flowed out into ancient floodplains to be held and slowly reabsorbed into the earth. Now, of course, this beautifully orchestrated system has been thrown completely out of whack by the building of a mind-boggling labyrinth of reservoirs, dams, levees and canals, all of which are highly regulated. Every so often, though, there is still flooding, as there was a couple of years ago along the San Joaquin River, and the value of restored wetlands, like those at the San Joaquin River National Wildlife Refuge, is allowed to shine.
Nature’s own water-treatment facilities:
Wetlands are remarkably efficient at improving water quality, as their plants, fungi and algae filter sediment, nutrients, waste and toxins out of the water. Pesticides, chemicals, and even heavy metals wash into wetlands from surrounding urban, industrial and agricultural areas. As water flows slowly through wetland vegetation, sediments laden with both nutrients and toxins are filtered out, settling to the bottom where they are either buried or broken down, rather than being washed into aquatic ecosystems beyond. Without wetland vegetation, aquatic habitats would become infiltrated with sediment and contaminated by runoff laden with excess nutrients and toxic chemicals.
Carbon sinks to counteract climate change:
Wetland plants take up carbon dioxide from the atmosphere through the process of photosynthesis, storing the carbon in living and dead plant material as well as in the highly organic mud. Coastal habitats like salt marshes sequester even more carbon than terrestrial forests! Additionally, peat bogs store an estimated 30% of land-based carbon.
Support biodiversity, and in turn, the economy:
At the interface of terrestrial and aquatic habitats, wetlands support an incredible amount of biodiversity, with up to 40% of all species worldwide living or breeding in wetlands (source). Many species we rely on for food spend at least part of their life cycle in wetlands. Ramsar estimates that the livelihoods of over 1 billion people worldwide are dependent on healthy and productive wetlands. In California, wetlands support more species of plants and animals than all of the other habitat types found in the state, combined!
Places of natural beauty and outdoor recreation (which also supports the economy):
Public access to wetlands allows local residents and tourists alike to enjoy outdoor recreational activities, such as bird and wildlife watching, fishing, waterfowl hunting, boating, kayaking, and hiking. The US Fish and Wildlife Service estimates that Americans spend over $100 billion annually on wetland-related recreational activities (source, source). I believe (and there are studies to back me up on this) that immersion in nature is imperative for our overall health and well-being, and wetlands provide tranquil settings in which to enjoy fresh air and sunshine while taking a contemplative stroll through a beautiful habitat.
Why do wetlands need protecting?
Although wetlands are excellent water filters, they can only take so much. Excess pollutants are carried into wetlands from a variety of sources, including agricultural and residential chemical pesticide and herbicide runoff, heavy metals from mining and industry, leaky landfills, oil dumping and spills, marinas where boats stir up sediment and leak oil, even from the very air itself. On top of all this, the introduction and spread of non-native plants and livestock grazing harm wetland vegetation.
World Wetlands Day Themes
2021 Wetlands and water
2020 Wetlands and Biodiversity
2019 Wetlands and Climate Change
2018 Wetlands for a Sustainable Urban Future
2017 Wetlands for Disaster Risk Reduction
2016 Wetlands For Our Future: Sustainable Livelihoods
2015 Wetlands For Our Future
2014 Wetlands and Agriculture: Partners for Growth
2013 Wetlands Take Care of Water
2012 Wetland Tourism: A great experience
2011 Forests for water and wetlands
2010 Caring for wetlands – An answer to climate change
2009 Upstream, Downstream: Wetlands connect us all
2008 Healthy Wetlands, Healthy People
2007 Fish for tomorrow?
2006 Livelihoods at Risk
2005 There’s Wealth in Wetland Diversity – Don’t Lose It
2004 From the mountains to the sea – Wetlands at work for us
2003 No wetlands – no water
2002 Wetlands : Water life and culture
2001 A wetland world – A world to discover
2000 Celebrating our wetlands of international importance
1999 People and wetlands- the vital link
1998 Importance of water to life & role of wetlands in water supply
1997 WWD celebrated for the first time
