Introduction

Paengaroa Mainland Island is situated on the banks of the Hautapu River, near the settlement of Mataroa, in the Central North Island.

Paengaroa is a special place for plants. Here you'll find many rare species and more divaricating plants (strange botanical ugly ducklings) than in any similarly sized area in New Zealand.

Swing bridge over the Hautapu River, Paengaroa Scenic Reserve. Photo: Astrid van Meeuwen-Dijkgraaf.
Swing bridge over the Hautapu River, Paengaroa Scenic Reserve

Because of its special flora, the 107ha Paengaroa Scenic Reserve became a mainland island in 1990, which also incorporates another 13ha of Railcorp land.

Rare species

Some of the plants in Paengaroa are nationally rare or have disjunct distributions (are only found in isolated pockets). These include:

  • Coprosma obconica - known at only one other North island site and a few sites in the South Island;
  • Pittosporum obcordatum - heart leaved kohuhu;
  • Korthalsella clavata and K lindsayii - two species of dwarf mistletoe;
  • Olearia gardnerii - New Zealand's third rarest tree. The country's largest population is found here. 

Heart-leaved kohukohu (Pittosporum obcordatum). Photo: Neill Simpson.
Heart-leaved kohukohu

Possums and weeds threaten Paengaroa mainland island's native plants and animals. Problem weeds at Paengaroa include ivy, elderberry, Chilean flame creeper, willow and cotoneaster.

Divaricating plants

Divaricating plants - sometimes called inside out plants - are tangled twiggy plants with small leaves. Once they get taller (about 3m high) some change so completely they are hardly recognisable from their earlier form.

One theory for these ugly ducklings is that the young, twiggy stage protected the plants from moa grazing. The more unattractive the younger plants looked the less chance they had of being eaten. Another theory was that the extreme climate – severe frosts, droughts and frequent floods – could have been the cause.

How Paengaroa became such a special place

A frosty morning at Paengaroa Scenic Reserve. Photo: Astrid van Meeuwen-Dijkgr.
A frosty morning at Paengaroa

The unique collection of plants at Paengaroa is a result of the climate and geology.

The area floods and is often waterlogged, yet also suffers droughts and can have frosts any day of the year.

Some of the plants in the reserve need good light, and light gaps are created by  ibbonwood, kowhai and narrow leaved lacebark which lose their leaves in winter.

Restoration of Paengaroa mainland island

DOC's work

Possum control began in earnest in 1992 with aerial treatment using 1080-laced cereal baits. With the reduction in possums, mistletoe flourished and plants soon reached over 1m across.

Weed management started in 1990 with DOC staff and volunteers removing around 14ha (about 28 football pitches) of ivy.

In 1996 Paengaroa was recognised for its rare plants and became a mainland island. Today, weed and pest control are main priorities for management of this special reserve.

Mainland Island Hui delegates gathered around one of the rare tree daisies, Olearia gardneri, in Railway reserve near Paengaroa mainland island, Mataroa. Photo: Astrid van Meeuwen-Dijkgraaf.
Mainland Island Hui delegates

Community involvement

The Mataroa community is invaluable for its local knowledge. Many have removed invasive weeds from their gardens and chosen not to grow bird-dispersed exotic plants.

Massey University, Forest and Bird and other conservation groups help with projects such as ivy control and robin monitoring, and local and district schools use the reserve and assist with any tree plantings.

You can help

  • Join the Manawatu volunteer programme
  • When visiting, please respect this unique refuge and its precious inhabitants
  • Be careful not to take plants or seeds into the reserve
  • Remove rubbish
  • Be a responsible cat owner
  • Think carefully about what you plant in your garden

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