Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Wetlands: Kidneys of the landscape

By Bala Tikkisetty

Intensive farming practices can result in significant amounts of contaminants, notably nitrogen, phosphorus, faecal matter and sediment, getting into our waterways.

With World Wetlands Day occurring on February 2, it is a good time to reflect on the impact of contaminants like these on our waterways, and the role of wetlands in helping to protect them.

Natural wetlands have been called the ‘kidneys of the landscape’ because of their ability to store, assimilate and transform contaminants lost from the land before they reach waterways. Like a giant kidney, wetlands help to dilute and filter material that could otherwise harm our lakes, rivers and other waterways.

Sadly, large areas of wetlands have disappeared with the development of farmland and they now occupy only about two per cent of New Zealand’s total land area. It is estimated that about 90 per cent of New Zealand’s wetlands have been drained – one of the largest wetland losses anywhere in the world.

Wetlands once covered large areas of the Waikato, but they are now some of our rarest and most at-risk ecosystems.

Wetland is a generic term for the wet margins of lakes, ponds, rivers, streams, estuaries, lagoons, bogs and swamps. They contain a diverse range of plants and animals and are home to many rare and threatened species, so conserving and restoring wetland habitats is worthwhile for many reasons.

Rainfall patterns, soil water status, groundwater levels, soil properties, drainage system design and land management practices can all affect the contaminant loads generated in farm drainage.

Nitrogen and phosphorous enter waterways through leaching and surface run off. Wetland vegetation uses these nutrients for growth. Wetlands remove up to 90 per cent of nitrates from ground water through a process called de-nitrification. Microbes living in wetlands absorb and break down nitrogen improving water quality.

Wetlands also play an important role in sediment management and reducing erosion. The plants trap sediment suspended in water, improving water quality, and in riparian areas their roots hold riverbank soil together.

Wetlands also help to regulate the flow of water from land, soaking up excess floodwater and then slowly releasing it to maintain summer flows or recharge ground water.

Providing habitat for many different plants and animal life, including rare or threatened species, is another role for wetlands. These areas are also essential breeding areas for whitebait species and game fish, as well as providing a rich source of insects for fish, birds and amphibians.

Fishers, shooters, naturalists and other water-based recreationists also make extensive use of wetlands. Their importance to Maori as mahinga kai (food gathering areas) and as a source of plants for medicines and dyes, is well recognised.

On an international level, healthy peat wetlands are important in helping to combat global warming, as they soak up excess carbon.

Waikato Regional Council provides free advice to landowners on managing wetlands, including information on fencing, planting of suitable riparian margins and weed control.

Fencing keeps stock out, stops pugging of wetland margins and enrichment from animal wastes. Appropriate planting around the edges of the wetland reduces pollution from surrounding farmland, provides cover for wildlife, reduces bank erosion and reduces the temperature of water through shading.

Of late, constructed wetlands, as trialled by NIWA, have been recognised as an effective technology for treatment of tile drainage waters.

Wetlands are worth caring for – failing to maintain their health is a risk too great to ignore.

ENDS

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

Gaza.Scoop: UNRWA School, Ambulances Attacked - Gaza MOH

The Ministry of Health Gaza expresses its horror and outrage at the latest Israeli massacre moments ago at an UNRWA school sheltering displaced persons in Beit Hanoun. Ten people have been killed and there is a large number of wounded. More>>

ALSO:

Gordon Campbell:
On Gaza And Burning The Israeli Flag

One of the selling points in New Zealand’s campaign for a temporary seat on the Security Council is that we have a pluckily independent voice to offer on international conflicts.

This image is not entirely self-delusional. When we did occupy a temporary UN Security Council seat in the 1990s, New Zealand was forthright about the need for the international community to actively respond to the Rwanda genocide. On April 14, 1994, New Zealand, Nigeria and the Czech Republic were the only nations to call for a forceful UN intervention to halt the killings. It was a proud moment in the diplomatic record of the Bolger government.

What then, is the current National government doing with respect to the slaughter in Gaza? More>>

 

Parliament Today:

Minister Told Of FBI Investigation, Says INZ: Coleman Must Quit Or Be Sacked Over Dotcom Case - Harré

Immigration New Zealand has done the right thing in distancing itself from Jonathan Coleman’s claims that ministers were not aware of FBI involvement in Kim Dotcom’s residency application, says the Internet Party. More>>

ALSO:

Valedictory Season: Maori Party Founders Say Goodbye

Two major Maori MPs gave there farewell speeches to Parliament Thursday outlining their history, experiences, triumphs and regrets. More>>

ALSO:

Resignation Not Accepted: Transport Minister Breaches Aviation Security Rules

"Running late for a plane at Christchurch Airport, I without thought breached airport and airline security rules by entering the gate lounge through a door usually used for exit only..." More>>

ALSO:

TAIC Report: Urgent Recommendations After Melling Rail Accident

The Transport Accident Investigation Commission has made four urgent recommendations to KiwiRail following the accident two months ago (27 May) when a Matangi passenger train collided with a stop block at Melling Station, Lower Hutt. More>>

ALSO:

Red Tape: Local Regulations Go Under Microscope

The Government says it is accepting nearly all of the recommendations the Productivity Commission has made on ways to improve local regulations. More>>

ALSO:

Spending Questions: Claudette Hauiti To Step Aside At Election

National Party President Peter Goodfellow confirms that he has received notification from List MP Claudette Hauiti that she plans to step aside at the 20 September election. More>>

ALSO:

EPA: Board Of Inquiry Rejects Basin Flyover By Majority Of 3 To 1

The independent Board of Inquiry delegated to decide on the Basin Bridge Proposal has, by a majority decision (3 to 1), cancelled the Transport Agency’s Notice of Requirement and declined its resource consent applications for the construction, operation and maintenance of a flyover on State Highway 1 in Wellington City... More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news