Increasing biodiversity on the escarpment

By Paul Callister, August 2017

One of the aims of Ngā Uruora is to increase biodiversity on the escarpment. Usually this means finding ways to support existing flora and fauna which are at risk. But at times the goal is to bring back populations that are currently missing. As yet, we have not translocated any birds, lizards or invertebrates. But we have been bringing back some plants that are currently missing or are found in very small numbers.

So how do we know what we should be bringing onto the escarpment? This is where we turn to botanical experts. In recent years we have had two visits from the Botanical Society. In 2010, Maggy Wassilieff produced a report entitled Vegetation of Paekakariki – Pukerua escarpment ecoforest. This gave a list of plants found within the area we call the Ecosite but also gave us some ideas of what plants we should be trying to bring into the area. In 2015 the Botanical Society prepared a similar report based on a walk around our Kohekohe Loop track.

Aerial view of the Ecosite

Another very useful guide has been a report prepared by Matt Ward while working for the Kāpiti Coast District Council. This report divides the coast into Ecological Districts. We are part of the Cook Strait Ecological as is Kāpiti Island and portions of the northern South Island. We have also talked to a range of other experts. This includes Rob Cross, Programme Manager of Biodiversity at the Kāpiti Coast District Council and our own committee member Finn Michalak who is Curator at Otari-Wilton’s Bush. Specialist native plant nurseries also give helpful advice.

As discussed in the blog about restoring our quarry we have been planting a range of trees that are rare or missing including totara, titoki, matai, large leaf milk tree and Northern rata. But this year we have also started to plant some other smaller rare or missing plants on other parts of the escarpment.

Ngā Uruora has many mahoe growing on the escarpment. In fact this is one of the pioneer species we have been planting over the last twenty years. Mahoe is a member of the Melicytus genus. But two other members of this group of plants are very rare on our patch. One is Melicytus obovatus (classified by the New Zealand Plant Conservation Network as ‘At Risk – Naturally Uncommon’)

Melicytus obovatus ready for planting

The other is Melicytus crassifolius –sometimes known as the Cook Strait Mahoe (‘At Risk – Declining’).

Berries on Melicytus crassifolius – Source Naturewatch by yejun, some rights reserved (CC BY-NC)

We have now started to plant these two rare mahoe and are planning to grow more for future plantings. Both are ‘lizard friendly’ plants.

Melicytus crassifolius planted on the escarpment

We have also started to re-introduce Aciphylla squarrosa var. squarrosa (commonly called speargrass or Spaniard grass) and Coprosma rhamnoides. Neither these are rare in our region but are currently missing from the escarpment.

Aciphylla squarrosa ready for planting

Coprosma rhamnoides planted near one of our lizard monitoring sites

The speargrass is a striking looking plant and is common on the Titahi escarpment and Mana Island. But don’t sit on it as it has very sharp spikes! Again both speargrass and C. rhamnoides are ‘lizard friendly’ plants.

One of the areas we have been planting is around the seat dedicated to the life of ecologist Geoff Park. Te Araroa track walkers will therefore get a chance to see examples of these plants. Hopefully lizards will also appreciate them.

“Lizard friendly’ plants near Geoff Park’s memorial seat