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

 

NZEI Survey Report: Special Needs Students Missing Out

The survey revealed that around 16 percent of students were on schools’ special needs registers, but nearly 90 percent of schools’ special needs coordinators did not believe there was adequate support for students and their learning... More>>

ALSO:

Interim Report: Waitangi Tribunal On Ture Whenua Legislation

Labour on Proposed changes to Maori land rules: “To have Treaty Negotiations Minister Chris Finlayson dismiss findings as ‘bizarre’ is totally disingenuous and disrespectful. What’s bizarre is Maori Development Minister Te Ururoa Flavell stubbornly pushing through this Bill before the Waitangi Tribunal has even completed its report..." More>>

ALSO:

Spy Update: Appointment Of GCSB Acting Director

GCSB Chief Legal Advisor Lisa Fong will become the Acting Director of the Government Communications Security Bureau (GCSB) from 15 February 2016, Minister Responsible for the GCSB Christopher Finlayson announced today. More>>

Protests Close Roads: TPP Signed In Auckland

“TPP was signed by Australia, Brunei Darussalam, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Viet Nam.” More>>

ALSO:

Emails Behind 'Diplomatic Immunity' Case: Whitehead Report Released

“As previously indicated the conclusions reached by Mr Whitehead’s investigation are not unexpected but they are very disappointing,” Mr Mccully says. “At the heart of the matter is a single email, along with procedural shortcomings, which gave Malaysian officials the impression it would be acceptable for Mr Rizalman to return to Malaysia." More>>

ALSO:

Gordon Campbell: On The Treaty/TPP Overlap, And Iowa

The fears about the ISDS provisions in the Trans Pacific Partnership deal are well-founded. The reality is that there is a sharp uptick in the occurrence of ISDS litigation in developed countries, and even the right wing likes of The Economist have been souring on the process for some time. More>>

ALSO:

Christchurch Red Zone Offers: Fresh High Court Proceedings

Grant Cameron, Solicitor for the Quake Outcasts said “the action seeks judicial review of the Crown’s recent decision to make a fresh offer to purchase properties from uninsured property owners in red zones. More>>

ALSO:

PM's Post-Cabinet Press Conference: Waitangi And TPP

Prime Minister John Key on Tuesday said his office has received an invitation for him to visit the Lower Marae on Waitangi Day, but was waiting for a meeting of the Te Tii Marae Trustees. More>>

ALSO:

Flagged: 'Wrong Colour' Bridge Flag To Change

NZ First: Only 13 days after National trumpeted its legally questionable flag on Auckland Harbour Bridge, it is now coming down because it is the wrong colour... “Mr Key’s latest flag fiasco is another waste of taxpayers' money. Given it is coming down, down is exactly the location where it should remain. More>>

ALSO:

School's In: Children Head Back To School

“Across the whole of this year we expect 61,820 five year olds will begin their primary schooling for the first time,” says the Ministry of Education head of sector enablement and support Katrina Casey. More>>

ALSO:

Dog & Lemon: FBI Disagrees With NZ Government Over Police Chases

Multiple studies, quoted by the FBI, show that once suspects realise they're no longer being chased; they tend to slow down to normal driving speeds and therefore become far less of a risk. The FBI report also categorically rejected the argument that abandoning police chases meant ‘giving in’ to offenders. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news