Sustainability & NZ Farming

Nenthorn red tussock

Why preserving Natural Beauty and Biodiversity is Important

Join me on a journey through the stunning Waikouaiti River catchment, starting in the Nenthorn area and ending at the coast at the town Waikouaiti.

For a small population someone went to a lot of trouble!

Located within the precincts of the beautiful city of Dunedin, New Zealand,. The Waikouaiti River “Mauri” offers a glimpse from the rolling high country to near the mouth of the river.

Waikouaiti River Mouth

The small town of Karitane, just 35 kilometers north of the city centre, serves as a popular holiday destination for residents of Dunedin. Come discover the beauty of the Waikouaiti River and its surrounding areas for yourself.

View of Karitane

The Journey Begins

Historic cottage
Macreas is now well known for it’s vast gold mining operation. Middlemarch is very much a hub for rural farming communities.

Clearing of Native and Snow Tussock Grasses

High country lands in New Zealand have long been treasured for their unique and diverse ecosystems, which include native and snow tussock grasses. However, the conversion of these lands for agricultural purposes has resulted in the widespread clearing of these grasses. This not only destroys the habitats of native species but also destabilizes the soil, leading to soil erosion and loss of fertility.

Snow tussock grasses on the Nenthorn Conservation Area. The remains of the building probably a remnant of historic gold mining operations.

Replacement with Exotic Non-Native Tree Species

In an effort to increase productivity and profitability, many farmers have replaced native grasses with exotic non-native tree species. This has further impacted the ecosystem by reducing the biodiversity and altering the natural balance of the land.

A few minutes drive from the last photo! Wilding pines spreading to the right

Wilding Pines: A Threat to New Zealand’s High Country

Wilding pines, also known as feral pines, are a major problem in New Zealand’s high country. They quickly take over the landscape, replacing native species and reducing biodiversity. The trees form dense stands that can cover vast areas of land, shading out native vegetation and altering the natural balance of the ecosystem. In addition, their extensive root systems can make it difficult for other plants to grow and compete for resources.

The clumped nature of wilding pines also makes it difficult for people or livestock to enter areas, further reducing the potential for land use and impacting the livelihoods of those who depend on these lands. As a result, the rapid spread of wilding pines is a significant threat to the sustainability and viability of New Zealand’s high country lands. Effective management and control of wilding pines is essential to protect these unique and valuable ecosystems.

The Negative Impact of Slash from Plantation Forestry Operations on Marine Ecosystems

A major contributor to marine sediment is the harvesting activities undertaken by plantation forestry operations. In particular, the period after clear-felling, known as the “window of vulnerability,” which typically lasts around 7 years, poses a significant risk of erosion and sedimentation.

With the increasing frequency of high rainfall events caused by the global climate crisis, steep land that has recently been harvested is more susceptible to landslides and erosion. The resulting sediment runoff can have devastating effects on the marine environment, smothering aquatic life and altering the delicate balance of the ecosystem.

In the Marlborough Sounds, this pollution is leading to significant adverse impacts on marine flora and fauna. The accumulation of slash, or the branches left to rot after harvesting, is a prime example of the short-sighted practices that are causing harm to the environment. The slash acts as a source of sediment during high rainfall events, contributing to the degradation of marine habitats and the decline of marine species.
It is crucial that we take steps to mitigate the negative impact of slash from plantation forestry operations on marine ecosystems. This includes proper management of harvesting activities, implementation of best practices to reduce sediment runoff, and investment in research and development to find sustainable solutions.

Loss of the Blotting Paper Effect

Native grasses severely degraded from waist high/several centuries old. With a backdrop of rural European style development. Nenthorn Conservation Area behind the photographer (myself).

The conversion of high country lands for agriculture has reduced their ability to absorb and retain water, causing soil loss and sedimentation in rivers. With increasing conversion at altitude, native vegetation regeneration is virtually non-existent.

Even more contrasts. Bare ground, cattle, cropping and sheep. With native tussocks on the road side.
If the terrain is at the limit of what a tractor can traverse, then in terms of rain water run off, it’s too steep. There will be severe downstream effects during floods.

Introduction of Cattle and Sheep Grazing

The introduction of cattle and sheep grazing has also had a significant impact on the high country lands. These animals consume large amounts of vegetation, causing soil erosion and degradation of the land. They also trample the soil and compact it, reducing its ability to retain water and nutrients.

Snow tussock area being cleared just a little east of the Nenthorn Conservation Area. Fertiliser trucks spreading… Presumably for planned pasture for stock.

Detrimental Effect on Marine Species

The soil erosion and sedimentation of rivers have had a detrimental effect on marine species near the coastline, including penguin populations. The sediment clouds the water, reducing the amount of light that reaches the ocean floor and impacting the health of marine plants and animals. Additionally, the increased nutrients from fertilisers can lead to harmful algal blooms, which can have toxic effects on marine life.

The Waikouaiti River flooding 2022. The access bridge to Karitane to the right. Taken very close to the fine weather photo above of a fishing boat. Photo courtesy the Internet.
Driving through the town of Waikouaiti 2018. Sediment is evident. From nearby creeks, and is typical of what washes down all the way from Nenthorn. Water supply tests in 2020 revealed concerning levels of lead in the town’s water supply (now fixed). Problems abound and compound on all fronts!

In conclusion

The conversion of New Zealand’s high country lands for agricultural purposes has had numerous negative effects on the ecosystem. From the clearing of native grasses and introduction of exotic non-native tree species, to the loss of the blotting paper effect and the impact on marine species, it is clear that the sustainability of these lands should be a top priority.

Honouring the native and indigenous status quo is a much better outcome for all concerned!
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