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

 

17 Year Sentences In Baby Moko Case: Attorney General On Plea Bargain

“The Crown’s decisions in this case, including the decision to accept the manslaughter pleas, were motivated by the need to secure convictions for this horrendous killing and to avoid the significant risk that either of the defendants could escape such a conviction because of evidential issues.” More>>

ALSO:

No Rail For New Harbour Crossing: National Giving Up On Rail In Auckland

The National Government’s decision to scrap two planned rail lines in Auckland shows it is giving up on a city-wide rail network in Auckland, and on thousands of commuters who sit in traffic jams every single day, the Green Party said today. More>>

ALSO:

Gordon Campbell: On The Ombudsman’s Verdict On Paula Rebstock And Ian Rennie

Unfortunately, the brave and damning report by Ombudsman Ron Paterson on the “flawed” and “unfair” inquiry conducted by Dame Paula Rebstock into events at MFAT pulls back the veil on a far wider issue. More>>

ALSO:

Charities' Report: Stressed Families - Overstretched Services

“Like so many of the whānau and families they serve social service organisations are under huge financial stress. The support demanded from desperate people in communities is far outreaching the resources available.” More>>

ALSO:

Detention: Wellingtonians Protest Treatment Of Refugees

Peace Action Wellington (PAW) and around 50 Wellingtonians blockaded the Australian High Commission, creating a symbolic detention centre to protest the Australian Government's policy of mandatory offshore detention for refugees and asylum seekers. More>>

ALSO:

Diver's Alarums: Breach Means Training Provider Must Repay $1.47 Million

The New Zealand School of Outdoor Studies is to repay $1.47 million (GST-exclusive) to the Tertiary Education Commission (TEC) following an investigation which showed that some student enrolments between 2009 -2014 could not be validated and that courses were under-delivered against their agreement with the TEC. More>>

ALSO:

Education: Government Plans Suggest Bulk Funding Return

Plans by the Government to return to bulk funding are likely to see increased class sizes and schools most in need missing out on much-needed resources, Labour’s Acting Education spokesperson Grant Robertson says. More>>

ALSO:

Interim Report: Auckland Looks Long Term To Pay-Per-Km Road Pricing

Aucklanders can expect to be paying variable rates per kilometre to travel on the city's most congested roads under an emerging transport strategy being formulated by the government and the Auckland Council. More>>

ALSO:

Despite Promises: Government Extends Iraq Deployment

Cabinet has agreed to extend New Zealand’s contribution to the joint New Zealand-Australia mission to train Iraqi Security Forces until November 2018. More>>

ALSO:

On The 'Terrorism' Card:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news