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Healthy Wetlands, Healthy People

Many people appreciate that wetlands are an important part of our environment, but not many would know that they are also good for our health.

World Wetlands Day on February 2 this year aims to raise awareness that healthy wetlands ALSO mean healthy people.

World Wetlands Day is celebrated by signatories to the Ramsar Convention on Wetlands, signed in Ramsar, Iran, in 1971 to coordinate international efforts to conserve wetlands.

There are 157 parties to the convention (despite its obvious current difficulties, Iraq was the most recent country to join in October last year) and worldwide Ramsar covers 1699 wetlands totaling 152 million hectares.

New Zealand has just six wetlands listed by Ramsar as having international importance but this number would be much higher if all our important wetlands were properly recognised – and protected. 

Our remaining wetlands can be found in a variety of places, from the heights of the South Island high country to our coastal estuaries - where the water table is at or near the surface of the land, or where the land is either permanently or temporarily covered by water.  They come in many different guises, including streams, swamps, bogs, lakes, lagoons, estuaries, mudflats and flood plains.

World Wetlands Day’s theme of Healthy Wetlands, Healthy People highlights the direct, positive effects on human health of maintaining healthy wetlands – and the direct negative effects of mismanaging wetlands that can result in the impairment of human health and even loss of life.

The damage Hurricane Katrina wrought upon New Orleans in 2005 is one of the most high profile examples of how destruction of wetlands can have catastrophic consequences for human health and life.

For thousands of years, sediment from the Mississippi River had replenished Louisiana's coastal wetlands. When New Orleans was built, many miles of cypress trees and wetlands separated the city from the Gulf of Mexico and its hurricanes. These wetlands removed much of the energy from wind and storm surges.

But large-scale engineering projects, including shipping channels and levees, diverted sediment and freshwater from the wetlands, diminishing the protection for Louisiana's coastline.

Ninety percent of the coastal wetland loss in the United States occurred in the Mississippi River Delta where much of Hurricane Katrina's wrath was felt.  Since the 1930s, more than 1.2 million acres of wetland has disappeared from the Mississippi River Delta.

The destruction caused by Hurricane Katrina was much worse than it would have been if the wetlands had been maintained in their natural state.

The impact of wetland health on human health is not always so cataclysmic – but is nevertheless significant.  All over the world wetlands are important for human health in protecting human habitation from weather extremes, and providing food, clean water and pharmaceutical products – and destruction of wetlands brings about the decline of these valuable health-giving services.

Wetlands perform a vital role in purifying fresh water, making it safe for human use by trapping sediments, nutrients and pollutants that would otherwise have a detrimental effect on human health.

Wetlands also provide a wide range of wild and cultivated food sources, including fish, shellfish, rice, seaweeds and a range of other plants and animals.

Humans have also used wetland plants and animals as a source of medicine for thousands of years.  For example willow contains the precursor of the painkiller aspirin; the semi-aquatic plant purple loosestrife is a traditional remedy for dysentery, medicinal leeches are used to treat a variety of health problems from thrombosis to glaucoma; and several seaweeds undergoing testing are showing promising signs in the treatment of diseases including AIDS, herpes, polio and cancer.

On the other hand, destruction of wetlands can have direct adverse effects on human health.  For example, burning of south-east Asian peatlands in 1997-98 affected the health of about 70 million people in six countries, including more than 200,000 people who were hospitalised with respiratory, heart, eye and other health problems caused by the burning.

Even in an affluent Western country like New Zealand, wetlands are important to support the health and wellbeing of the human population.

Maintaining wetlands, rather than draining and clearing them to make way for development, provides a buffer zone of protection against some of the serious storms, floods, droughts and erosion which New Zealand has experienced in recent years.  With climate change these weather extremes are likely to become even more frequent – and the protection provided by wetlands even more important.

New Zealand’s wetlands also provide significant physical and mental health benefits through a huge variety of recreational opportunities – such as fishing, whitebaiting, eeling, duckshooting, walking, boating, swimming and birdwatching (many of New Zealand’s most threatened birds live in wetlands).

Wetlands also provide important food sources, such as whitebait, eels and other fish, ducks and other game birds, and plants that New Zealanders have used for medicines and weaving since pre-European times. 

The protection against pollution, erosion and storm damage provided by wetlands also helps protect food sources that are supplied by farming and horticulture – and wetlands filter out much of the nutrient run-off from agricultural production, protecting downstream environments.

Although wetlands are one of New Zealand’s most important habitats and provide these important health benefits, they have almost been wiped out in the last 200 years – fewer than 10% of our wetlands remain and this destruction continues.

Responsible riparian management can protect our remaining wetlands through appropriate planting, fencing to exclude stock, reducing pollution and nutrient run-off going into wetlands, responsible recreational use, pest control, and preventing further loss of wetlands through draining and development.

Once wetlands are gone they can be difficult – but not impossible – to restore to their former state.  The wetland at Pauatahanui, north of Wellington, for example had been drained and was used as farmland and a go-kart track 20 years ago.  Today, thanks to the efforts of Forest & Bird and others, it has been restored to a wonderful wetland supporting a wealth of plant and animal life.  It is living proof that we can restore health to wetlands – and people.

Further information on this site: Wonderful Wetlands

This page was updated on 31 January, 2008