New Zealand’s highway restorations

Posted on April 30, 2015

On the road to one of New Zealand’s largest highway ecological restorations

During the last few months Kauri Park has been busy collecting seed for the new Mackays to Peka Peka expressway (M2PP), one of the largest ecological restoration projects associated with a state highway development that this country has ever seen.

This significant project is taking place in the Foxton Ecological District, a thin strip of coastal land running from Pukerua Bay to Hawera, featuring an incredibly diverse range of habitats. With more than 50 species and 800,000 plants to be planted in 2015 and 2016, and a range of both private and government land ownership to negotiate, the plant supply for this project has required more than five years of planning.

In 2009, the main contractors the Alliance’ contracted Boffa Miskell to plan and design the revegetation and planting mitigation works. As a result of a Boffa Miskell initiative, the Alliance agreed to undertake some initial seed collection and in early 2012 Kauri Park were awarded the contract for this work.  In 2012, the Alliance acted again on the recommendation of Boffa Miskell, to set up a  planting substrate and plant species trial. This was established  in August 2012, with Kauri Park supplying the plants for that trial. This provided useful information on soil mixes and the identification of the preferred species for the M2PP project.

In Feb 2014, The Alliance awarded the landscaping contract for M2PP to Natural Habitats, and Natural Habitats awarded the plant supply to Kauri Park.

To help protect the biodiversity of this unique region, the seeds are being eco-sourced. Broadly speaking eco-sourcing is the sourcing of plant material from the region it is to be replanted back into to retain the genetic footprint that has evolved over many generations. This is now considered best practice for restoration work and mitigation for development.

For this project, enough collection points were secured to source most of the material in areas south of Himatangi. A number of challenges were faced collecting in this region, in particular, it was necessary to negotiate access  to the best seed collection points which were either in private ownership, under local government or in DOC estate.

It has taken nearly two years of preparation in the build-up to this collection year. Working under strict guidelines, our first goal was to locate the species and secure enough collection sites to spread the load of seed collection over as many sites and individual plants as possible. We have been fortunate to gain access to some of the most environmentally important and ecologically interesting sites in this region to achieve this.

Prior to the main collection, germination testing was undertaken of core species to check viability and check any evidence of cross pollination. As a result of this testing, a small number of collection points were ruled out.

With close to 800,000 plants to be planted in 2015 and 2016, this seed collection season is the most important and substantial year to collect. Further substantial plantings will occur in 2017.

The species selection for this contract is diverse, with over 50 species being originally required. A number of habitats are being affected by the M2PP bypass, including sand dunes, coastal forest, riparian, and wetland habitats. To give an indication of the diversity of species being eco sourced, these include rushes eg Baumea articulata, shrubs eg Melicope ternata, and forest trees eg Dacrycarpus dacrydioides.

This season has provided its challenges for a number of species. Some core species did not flower while the drought affected the quantity of seed from other species. However the seed collected this year is of good quality and, having a good number of collection sites, the quantity of seed required is being achieved.

Approximately 90% of the species list will be collected this year with the 10% balance to be collected next year when the plants have another flowering/fruiting cycle. This year’s collection will take approximately five months to complete.

We have met many people during our time collecting in this region, who are passionate about this project and what Kauri Park is doing with eco sourcing. These people understand the significance of this planting and the importance of getting it right.

We would like to extend our special thanks to all the private land owners, Nga Manu Wildlife Reserve, local government, local iwi and DOC for granting Kauri Park permission to access some of the most amazing ecologically diverse areas in the Foxton Ecological District. Without their permission and understanding of environmental issues, we would not have been able to undertake this collection.