NZ’s Wetlands, Its Destruction and Care, Environmental Impacts

The largest wetlands in New Zealand’s Northland region have suffered substantial damage. This 55-hectare wetland, roughly the size of 54 rugby fields, has been degraded due to livestock presence, pesticide use, and 600 meters of drainage (Pitman, 2025).

Located between Kaimaumau and the Houhora Heads, north of Kaitāia, this wetland is classified as a high-priority conservation area by the Northland Regional Council and the Department of Conservation. It is home to numerous endangered species, including various plants, birds, reptiles, swamp kauri, and some of the most valuable timber in the world.

In recent years, wetlands have been severely affected by large-scale wildfires that humans accidentally ignited. In 2022, a massive fire in the Kaimaumau wetlands in the Far North produced 515,000 tonnes of carbon dioxide emissions. Additionally, more than 600,000 tonnes of carbon were released into the atmosphere from two of New Zealand’s most important wetlands during recent fires. This situation underscores the critical need to keep wetlands hydrated. MWLR scientist Jack Pronger noted that the carbon loss from these two fires accounts for about 5% of New Zealand’s annual emissions reduction target for the 2026-2030 period (Dinsdale, 2024).

Companies have been digging timber in these wetlands without permission, diverting waterways, and clearing vegetation, resulting in hefty fines. Additionally, several avocado growers in the area have drawn water from aquifers that supply the wetlands, putting them at risk of drying out. So far, these farmers have not faced prosecution for their actions.

In June 2023, a hydrologist from the Northland Regional Council discovered that the wetlands were degraded. However, it took a year for an official inspection to occur, during which officials found that vast areas of vegetation had been illegally cleared and 600 meters of unauthorized drainage had been installed.

This led to an abatement notice to stop the work immediately and a search warrant issued in August 2024. Following this, the NRC sought legal intervention to enforce rehabilitation efforts, ensuring the wetland could recover from the extensive damage caused by farming activities.

Wetlands are the kidneys of the land.

Dean Baigent-Mercer, a Northland conservation advocate for Forest and Bird, thanked the NRC for taking action against landholders causing environmental damage. This case exemplifies the need for effective freshwater policies.

“Over 90% of wetlands nationally have been destroyed, and it is appalling to see the impacts on the Kaimaumau wetland over the past few years, with the drainage and land clearance being so deliberate,” he said.

Baigent-Mercer referred to wetland waterways as “the kidneys of the land” and urged the Government to invest in practical measures to protect wetland ecosystems, safeguard threatened species, and enhance carbon storage.

Human activities pose the main threats to New Zealand’s wetlands. These include the reclamation and draining of wetlands for development, which reduces their area; pollution due to excess runoff of sediment and nutrients from farmland; invasive plant and animal species; grazing by livestock, which damages vegetation, decreases soil stability, and contributes to pollution; and forest harvesting near wetlands, which damages vegetation and causes erosion.

What are wetlands?

Wetlands are areas where water plays a significant role in shaping the environment and supporting the organisms that inhabit them. They can be classified as freshwater or estuarine wetlands and are characterised by water at or near the land’s surface or by periodic flooding.

Historically, wetlands were viewed as unimportant or undesirable; however, they are now recognised for their essential functions. These functions include filtering water, trapping sediment, reducing flooding, protecting coastal regions from storm surges, and maintaining groundwater levels. Such services are crucial for enhancing resilience and adapting to the impacts of climate change.

Additionally, wetlands play a crucial role in returning nitrogen to the atmosphere. New Zealand is home to the highest concentration of wildlife found in any habitat.

Protecting wetlands in New Zealand is crucial due to their essential environmental services and significant contribution to climate change adaptation and mitigation.

The Global Center on Adaptation highlights five key ways wetlands help address climate change.

• First, wetlands store significant amounts of carbon through the plant material and organic matter found in their soil.
• Second, they protect against floods and storms by absorbing and retaining excess rainwater.
• Third, wetlands help regulate temperatures by maintaining moisture levels.

Additionally, they support a diverse range of plant and animal species, preserving biodiversity. Therefore, protecting and restoring wetlands is a crucial strategy for enhancing resilience and adapting to the effects of climate change.