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

AMA: Scoop's 'Invisible Paywall'

Operation Chrysalis: The Final Countdown - Thanks & There's Still Time To Pledge

Phew! We are now counting down the hours to the end of this crowd-funding campaign at 11pm on Sunday. Thankyou to all those Scoop readers and supporters who have pledged already. You have been awesome. But this is not over yet. More>>

 
 

PARLIAMENT TODAY:

IPCA Reports: Significant Problems In Police Custody

In releasing two reports today, the Independent Police Conduct Authority has highlighted a number of significant problems with the way in which Police deal with people who are detained in Police cells. More>>

ALSO:

Inspector-General of Intelligence and Security: Inquiry Into GCSB Pacific Allegations

The complaints follow recent public allegations about GCSB activities. The complaints, and these public allegations, raise wider questions regarding the collection, retention and sharing of communications data. More>>

ALSO:

TPPA Investment Leak: "NZ Surrender To US" On Corporates Suing Governments

Professor Jane Kelsey: ‘As anticipated, the deal gives foreign investors from the TPPA countries special rights, and the power to sue the government in private offshore tribunals for massive damages if new laws, or even court decisions, significantly affected their bottom line’. More>>

ALSO:

Werewolf: The Myth Of Steven Joyce

Gordon Campbell: The myth of competence that’s been woven around Steven Joyce – the Key government’s “Minister of Everything” and “Mr Fixit” – has been disseminated from high-rises to hamlets, across the country... More>>

ALSO:

RMTU: No Public Submissions On International Government Procurement Deal

“The government is preparing to assent to the Government Procurement Agreement, a World Trade Organisation Treaty which opens up New Zealand Government contracts to foreign companies and closes the door on local businesses and their workers. However the Foreign Affairs, Defence and Trade Select Committee is refusing to take public submissions on the decision.” More>>

ALSO:

Gordon Campbell:
On Pacific Spying

So New Zealand spied on its friends and allies in the Pacific – and has not only been passing on the results to the NSA, but has apparently passed on the details of the Pacific’s relations with Taiwan to our other best friends, the Chinese. On the side, the Key government has also been using the security services to gauge the chances of Trade Minister Tim Groser landing the top job at the WTO... More>>

ALSO:

State Housing Transfer: Salvation Army Opts Out

The Salvation Army has decided against negotiating with Government for the transfer of Housing New Zealand stock.
More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news