Wetlands are part of the spectrum of ecosystems that include the reefs.World Wetlands Day marks the date of the signing of the Convention on Wetlands on 2 February 1971, in the Iranian city of Ramsar on the shores of the Caspian Sea. It is run by The Ramsar Convention on Wetlands.
What do wetlands do for us?
Why should Singaporeans care?
Destruction of wetlands around us affect us too.
Here's an extract from the World Wetlands Day website
Wetland food
Adequate, good quality food is a prerequisite for healthy people, and wetlands are key contributors, supplying us with, for example, fish (including shellfish), and plants (including fruits, seeds, as well as the vegetative parts). One billion people rely on fish as their main or sole source of protein and many more consume fish regularly. In terms of cultivated wetland plants, rice is the most important at a global level, providing 20% of the world's dietary energy supply. Other wetland plants, such as seaweeds, although not harvested on the same scale as fish, are still an important source of food for local use and for international markets. Indirectly, wetland plants often play a vital role as a food for livestock on which the health of billions of people depend.
Well managed, our wetlands will continue to provide food to keep us healthy - but there are many human actions that negatively affect the capacity of wetlands to continue to provide for us. Pollution, excessive water abstraction, poor sanitation, overharvesting and, of course, wetland destruction, all reduce or destroy the capacity of wetlands to provide food for human consumption.
Clean water
We've been saying it for years - inland wetlands (rivers, lakes, ponds, marshes, etc.) perform a vital function in filtering and purifying freshwater, rendering it 'clean' for human consumption. And never has it been a more valuable service for human populations than today when over one billion people lack access to clean water supplies. But wetlands can only provide us with clean water if we keep them healthy through effective management. What happens when we destroy our wetlands is obvious - we lose this source of clean water, as well as all the other ecosystem services they provide. And what happens to our clean water supply when we add too many human by-products to wetlands? . . . Find out more in our section on pollution.
Water pollution
Despite the capacity of freshwater wetlands in purifying water, they do have their limits. They can only deal with so much agricultural runoff, so much inflow from domestic and industrial wastes. And of course the human species is capable of adding much more - toxic chemicals (such as PCBs, DDT and dioxins), antibiotics from animal husbandry, untreated human sewage, pesticides that act as 'endocrine disrupters' . . . and more. We can, and do, readily move beyond the purifying powers of wetlands so that these sources of freshwater, and the food they supply, are rendered unfit for consumption and a danger to human health.
Of particular concern are the 2.6 billion people today who lack access to adequate sanitation. Poor sanitation adds to the microbial contamination of drinking water provided by wetlands - and then to sickness and sometimes loss of life.
Wetlands act as filters or traps for many pathogens - when the passage of water through wetlands is long enough, pathogens lose their viability or are consumed by other organisms. Human-made wetlands are being constructed in urban and rural areas to perform just this function and thus prevent untreated sewage reaching natural wetlands that are used as an immediate source of drinking water.
Water-related diseases
In many parts of the world, human health is closely linked to water-related diseases. Malaria, because mosquitoes breed in wetlands, and diarrheal infections (including cholera) because of sewage contamination are globally the worst in terms of their severity of impact, accounting for 1.3 and 1.8 million deaths respectively in 2002, and affecting the health of many, many more. Fatalities are almost entirely in children under 5 years of age. Diarrheal diseases affect both African and south Asian countries, whereas malaria's impact is largely in Africa but also significant in many parts of Asia and the Americas.
While malaria and diarrheal diseases are the two worst in terms of human impact, we might add to this the debilitating effects of other wetland-related diseases such as schistosomiases, Japanese encephalitis, filariases, onchocerciasis and others.
Diarrheal diseases can be controlled through provision of clean water, good sanitation practices and hygiene education. Poorly treated human sewage contains pathogens that are a key cause of diarrheal infections - and wetlands (both inland and coastal) can be an important transport mechanism for such pathogens where sanitation is poor.
Controlling malaria was one of the driving forces for wetland destruction in the past, especially in Europe, but this has led to the loss of vital ecosystem services such as water and food and is not considered an option today. Solutions that are working, at least in some areas, range from the use of fish that consume the mosquito larvae and bacterial larvicides that kill them without affecting other organisms, to better design, management, and regulation of dams and irrigation schemes and water drainage systems that can reduce breeding sites.
Floods
Floods and storms have affected human lives since the beginning of civilization, but all types of floods - riverine and coastal floods and storms, sudden snow melts, floods after intense rainfall - have become more destructive in recent decades, because increasingly human infrastructure is being built in flood-prone areas, and they are likely to be even more pronounced in the future. This we are all aware of from the international media, from statisticians, and perhaps from our own personal experiences.
The direct and immediate impacts on human health include loss of life, injuries, and, within a very short period of time, the lack of clean water and destruction of sewage systems, which result in another set of threats to human health - diarrhea, cholera, and other life-threatening, water-related ailments. Receding floods in some countries also provide the perfect environment for malaria-carrying mosquitoes. Finally, there are the longer term effects on mental health, such as anxiety and depression that often follow a major flooding event.
While we cannot easily prevent major floods, we can ensure that we benefit from the flood protection services that wetlands supply free of charge. Rivers, lakes and marshes slow down and retain floodwaters but only if we do not build our urban centres on natural floodplains and are more thoughtful about the broader implications of channellising our rivers and draining our marshes.
Burning peatlands
Controlled burning has been used effectively in peatland management in various parts of the world, but events in recent years in southeast Asia have highlighted the fact that extensive and uncontrolled burning can have serious direct effects on human health. For example, the largely deliberate burning for land-clearing in 1997-1998 in southeast Asian peatlands affected around 70 million people with around 12 million people requiring health care for respiratory problems. Significant burning events since then have continued to affect the health of large numbers of people.
In the longer term, peatland burning and drainage activities have led to massive increases in the emissions of greenhouse gases, contributing to climate change, and these activities have often destroyed local livelihoods as well.
Water availability
If water is extracted more rapidly than it is naturally replenished, wetland ecosystems will, in extreme cases, collapse, with a complete loss of ecosystem services. The effect of such extreme cases is costly in terms of human health. A well-documented example is the Aral Sea where water abstraction for irrigating crops reduced a vibrant wetland to dust - causing loss of livelihoods in the short term and, in the longer term, seriously impairing the health of communities that lived around the sea through the health effects of dust storms, erosion, and poor water quality for drinking and other purposes.
While this may be an extreme example, there are many cases where a dramatic reduction in water availability results in significant negative effects on human health. In Lake Chad, a lake shared by Cameroon, Chad, Nigeria and Niger, climate change, the demand for irrigation water upstream, and poor management decisions in the basin have reduced the size of the lake by 90% over the past 40 years. The net effect on the 20 million people, mainly fishers and farmers, who rely directly on the lake is rising levels of malnutrition, in turn leading to a much increased vulnerability to diseases. A major project is underway to reverse this situation.
Wetland medicines
Many wetland plants and a number of animal species have been used in traditional medicines for millennia and this continues today. They are also used in homeopathic medicines, an ever-growing industry in the developed world, and have a role in the development and production of modern medicines. Over-collection, destructive harvesting techniques, and habitat loss and alteration all challenge the capacity of wetland species to continue to fulfill these roles.
Mental well-being
The world's population is becoming concentrated in urban areas, particularly along coasts, and our urban populations are becoming more and more physically inactive. The World Health Organisation estimates that depression and depression-related illness will become the greatest source of ill-health by 2020, and the effects on health of physical inactivity in urban populations is becoming ever more costly in terms of medical treatment. We use urban green spaces, including rivers, lakes and reservoirs, for recreation, for education, and for relaxation. The value of green spaces in improving the mental and physical health of urban populations is gaining greater recognition and current studies indicate measurable physical and psychological benefits from regular contact with urban green spaces. Urban wetlands have a key role to play here.
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