From farm to forest – the transformation of Mana Island

From farm to forest – the transformation of Mana Island

Mana Island, near Wellington, is one of Aotearoa New Zealand’s conservation success stories. Farmed for more than 150 years, the island is now covered with forest that is overflowing with an abundance of endemic birds, lizards and insects. Using pairs of images taken 50 years apart, natural history curator Dr Colin Miskelly describes how and why the island was transformed from a farm to a thriving sanctuary.

Special lizards

Tony Whitaker (1944–2014) was a science technician working for Ecology Division, Department of Scientific and Industrial Research, when he first visited Mana Island in June 1972. He was already a leading authority on New Zealand lizards, and made two remarkable discoveries that month: species that were subsequently given the names McGregor’s skink and goldstripe gecko. The skink discovery was particularly noteworthy, as the nearest population is on a tiny island off Whangarei (where Whitaker himself had discovered them in 1968).

A brown skink with darker patterns on it is sitting on some leafy mulch with its tail wrapped around to its right.
McGregor’s skink, Mana Island. Photo by Anthony Whitaker MNZM; 2008. Gift of Vivienne Whitaker, 2020. Te Papa (O.049935)
A greenish-brown gecko is on a flax leaf at night.
Goldstripe gecko, Mana Island. Photo by Anthony Whitaker MNZM; 2008. Gift of Vivienne Whitaker, 2020. Te Papa (O.049774)

The DSIR team also confirmed that Cook Strait giant wētā had survived on the island, and that mice were the only pest mammals present. The absence of rats and stoats greatly increased the conservation potential of the island.

A giant wētā is sitting on a hand and taking up most of the space.
Cook Strait giant wētā, Mana Island. Photo by Leon Berard

Before and after images

In addition to these biological discoveries, Whitaker took a series of images of Mana Island, which were among the thousands of images gifted to Te Papa by his wife, Vivienne, in 2020. With the 50-year anniversary of these images looming, I sought permission from the Department of Conservation to visit Mana Island in June 2022, to retake the images from the same vantage points. These paired images illustrate the profound changes on Mana Island since Whitaker’s first visits.

Scrub along a coastal beach. Healthy bush along a coastal beach.

The view south from McGregor’s Rock to Shingle Point, showing natural regeneration from mingimingi (Coprosma propinqua) in 1972 to taupata (Coprosma repens) in 2022. Before: Mana I, Cook Strait, Anthony Whitaker MNZM; photographer; June 1972; Mana Island. Gift of Vivienne Whitaker, 2020. Te Papa (CT.066757). After: June 2022 photo by Maarten Holl, Te Papa (206599)

Unexpected management regime changes

In 1972, Mana Island had been a Crown-leased sheep farm for more than 100 years. Unbeknown to the visiting scientists or the lease-holder, the government was poised to take over the lease, in order to manage the island as a quarantine research station for exotic sheep breeds.

The view down onto Shingle Point in 1972 and 2022, showing natural regeneration on the foreshore, and planted slopes in the foreground in 2022. Before: Raised beach by woolshed, Anthony Whitaker MNZM; photographer; June 1972; Mana Island, colour transparency. Gift of Vivienne Whitaker, 2020. Te Papa (CT.067097). After: June 2022 photo by Maarten Holl, Te Papa (206595)

Between 1973 and 1978, the Ministry of Agriculture and Fisheries invested the equivalent of more than $26 million in infrastructure on the island, building three houses, a wharf with overhead lighting, a research laboratory and numerous farm buildings, installing three diesel generators, and erecting many kilometres of fencing. This huge investment in the improvement of New Zealand’s sheep flock came to a shuddering halt in 1978. All 2,000 sheep were slaughtered and buried after an outbreak of scrapie disease (the sheep equivalent of mad cow disease).

Houses and bush by the sea 1986 Houses and bush by the sea 2022
The flat behind Landing Bay in 1986 and 2022, showing infrastructure built during the MAF era (1973–75), plus Lands & Survey era stockyards at right (the cattle were removed in April 1986). This was one of the first areas planted in the late 1980s and early 1990s. February 1986 photo by Don Newman. June 2022 photo by Maarten Holl, Te Papa (206584)

The Department of Lands & Survey ran dairy bulls on the island through to 1986, when the decision was made that the island should be used solely for conservation purposes.

A scrub and gorse covered hillside. A native bush covered hillside.
Shearwater Point, Mana Island, in 1972 and 2022, showing predominantly natural regeneration in 2022. Before: P. griseus colony, Anthony Whitaker MNZM; photographer; Jun 1972; Mana Island, colour transparency. Gift of Vivienne Whitaker, 2020. Te Papa (CT.067086). After: June 2022 photo by Maarten Holl, Te Papa (206576)

Creating a forest – and getting rid of the mice

The removal of the last farm stock from Mana Island in April 1986 was the precursor of a major revegetation programme. Between 1987 and 2011, close to 443,000 trees were planted on the island, using local seed sources. And in 1989, Colin Ryder (from the Wellington branch of Forest & Bird) led a successful mouse eradication project – the largest in the world at the time.

The view south over lower Astons Valley and Weta Valley, in 1972 and 2022, showing sheltered sites that were planted early in the revegetation programme. June 1972 photo Tony Whitaker. Gift of Vivienne Whitaker, 2020, Te Papa (CT.067087). June 2022 photo by Maarten Holl, Te Papa (206588)

Planting was first attempted in the sheltered gullies, before moving up onto the wind-swept plateau. Planted forest now covers about 37% of the island, merging seamlessly with the original 4-hectare forest patch, and natural regeneration on the coastal slopes.

A valley covered in pink heather. There are hills in the background. A valley with a lot of bush. There are hills in the background.
The view south across the head of Forest Valley, in 1972 and 2022, showing the original forest remnant and subsequent planting on the plateau to the south-west. Before: Bush Gully, Anthony Whitaker MNZM; photographer; Jun 1972; Mana Island, colour transparency. Gift of Vivienne Whitaker, 2020. Te Papa (CT.067096). After: June 2022 photo by Maarten Holl, Te Papa (206607)

A scrubby and dry-looking hillside. A hillside filled with native bush.
Part of the Mana Island plateau, showing sheep grazing in 1972, and planted vegetation in 2022. Before: Main plateau, Anthony Whitaker MNZM; photographer; Jun 1972; Mana Island, colour transparency. Gift of Vivienne Whitaker, 2020. Te Papa (CT.067098). After: June 2022 photo by Maarten Holl, Te Papa (206612)

Restoring the wildlife

With the mice gone and a forest created, Mana Island became suitable for a great diversity of endemic wildlife. Some species found their own way to the island (e.g. the tūī, pūkeko and pied shags that are now breeding there, and the visiting kererū and kārearea), while many others were introduced as part of a comprehensive ecological restoration programme.

A green parrot on the end of a branch with blue sky behind it.
Yellow-crowned parakeet / kākāriki – one of eleven bird species successfully translocated to Mana Island and now thriving there. Photo by Leon Berard

The full project, with many more images, is described in detail in ‘From farm to forest – 50 years of ecological transformation on Mana Island, New Zealand’, published in Te Papa’s journal Tuhinga.

Gorse-covered cliffs rising up from the sea. There is an island in the distance. Gorse-free cliffs rising up from the sea. There is an island in the distance.
The west coast of Mana Island, looking north-east towards the trig and Kapiti Island, in 1972 and 2022, showing natural regeneration in 2022. Before: North to Kapiti I along west coast, Anthony Whitaker MNZM; photographer; June 1972; Mana Island, colour transparency. Gift of Vivienne Whitaker, 2020. Te Papa (CT.067090); After: June 2022 photo by Maarten Holl, Te Papa (206591)

Acknowledgements

With many thanks to Vivienne Whitaker, Maarten Holl, Leon Berard, and Don Newman for providing images and supporting their reproduction here and in the Tuhinga article. The Department of Conservation, Ngatitoa Rangatira, and the Friends of Mana Island are acknowledged for their ongoing commitment to the ecological restoration of Mana Island.

7 Comments

  1. Great to get a view of progress on Mana Island. Such a wonderful effort from volunteers is a treasure for eveyone.

  2. So whats happening on Kapiti Island ? when I was a boy and visited with the Forrest and Bird, the northern part was still farmed.

    1. Author

      Kia ora Andrew
      Farming on Kāpiti ceased c.1970. For a comprehensive account of the ecological restoration of the island, I recommend Kerry Brown’s 2004 book ‘Restoring Kapiti: nature’s second chance’ (University of Otago Press, 128 pp).
      Ngā mihi
      Colin

  3. Great before and after images. So important for everyone to see and realise how long it takes. Just requires long term vision as is the case with most restoration projects.

  4. Very interesting. I visited once a few years ago and its great to get this happy update.

    Olwen Mason

  5. Love the before and after pics. Really shows what can be achieved with the right support.

  6. What a difference for the better over fifty years makes.

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