Benefits of wetlands on farm properties
Intensive farming practices can discharge significant amounts of contaminants, notably nitrogen, phosphorus, sediment and pathogens into our waterways.
Wetlands are like giant kidneys protecting the health of waterways – they help dilute and filter material that could otherwise harm our lakes, rivers and other waterways. Natural wetlands have been appropriately termed as the ‘kidneys of the landscape’, because of their ability to store, assimilate and transform contaminants lost from the land before they reach waterways.
With World Wetlands Day on February 2, it is a good time to reflect on these and other benefits that wetlands provide. Wetland is a generic term for the wet margins of lakes, ponds, rivers, streams, estuaries, lagoons, bogs and swamps.
Wetlands once covered large areas of the country. Now they are some of our rarest and most at-risk ecosystems.
It is estimated that about 90 per cent of New Zealand’s wetlands have been drained.
This is one of the largest wetland losses anywhere in the world. Wetlands now occupy only about two per cent of the country’s total land area.
So the combination of more agriculture and less wetland contributes to the risks to our rivers and streams, but this also indicates strategies for reducing the effects of agriculture – by incorporating wetlands into farms. Sometimes it may be as simple as fencing out existing wet areas, or it might involve creating one with a low bank.
Many farms have low lying and wet areas that can be managed as small wetlands with minimal impact on farm production, but potentially major benefits for water quality and biodiversity.
Nitrogen and phosphorous enter waterways through ground water and surface runoff. Wetland vegetation uses these nutrients for growth.
Waikato Regional Council can offer free advice to landowners on managing wetlands, including information on fencing, planting and weed control.
This Waikato dairy and drystock farm has 12 wetlands of various sizes, 5ha of manuka planted and another 8ha planned.