Holcim New Zealand, New Zealand: Cape Foulwind quarry - 20 years of rehabilitation.

Holcim New Zealand, New Zealand: Cape Foulwind quarry - 20 years of rehabilitation

The 120 hectare Cape Foulwind quarry is located in the Buller District of the West Coast of New Zealand's South Island. The quarry has been in operation since 1957 and is ISO 9001 and 14001 certified. It is the largest limestone quarry in New Zealand, supplying over 1 million tons of limestone and marl to Holcim's Westport plant.

The Cape Foulwind landscape is dominated by rocky coastlines, bluffs, steep escarpments, and the open seascape of the Tasman Sea dotted with offshore granite stacks and reefs. The geology consists of Oligocene sedimentary sequence of mudstone, sandstone and limestone on granite basement rock. Re-generating coastal vegetation now covers much of the coastal escarpment.

Original European occupation of the area from the mid 1800's caused significant habitat destruction through deforestation and the drainage of wetlands. The clearing of bush and draining of wetlands enabled farming practices and quarrying to occur. However, more recently rehabilitation of the quarry and it's surrounds has increased local biodiversity by restoring coastal and terrestrial habitats. Rehabilitated coastal vegetation now covers much of the coastal escarpment and planting of significant numbers of terrestrial vegetation now swathe overburden dumps and other previously quarried areas.

Currently quarry lands and the adjacent Tauranga Bayarea, are home to colonies of the endangered New Zealand fur seal (arctocephalus forsteri) and little blue penguin (eudyptula minor) are located. Sooty shearwaters (puffinus griseus) breed on the headlands, and white fronted terns (sterna striata) on Wall Island. Western weka (gallirallus australis australis) and numerous endemic bush bird species are also common in the quarry and surrounding areas.

As part of the onsite wetland restoration, a baseline biodiversity assessment was conducted to determine biodiversity values in the wetland catchment and coastal areas. The following threatened fauna were identified:

Threatened Fauna
Threat status Fauna
Nationally critical White heron (visitor only, no breeding)
Nationally endangered Long-tailed bat, New Zuealand, Western weak, Sout Island robin, South Island fernbird, Australasian bittern, Grey duck
Nationally vulnerable Caspial tern
Sparse West Coast green gecko, Brown skink
Range restricted Bellbird
Gradual decline Great spotted kiwi, Longtailed cuckoo, South Island rifleman, Kereru-New Zealand pigeon, White-fronted tern, Blue penguin, Banded dotterel, Speckled skink, Koura
  • To fully restore the land surrounding the Cape Foulwind Quarry to maturing native forest by 2043.
  • Measure the existing biodiversity with the goal of enhancing the biodiversity of forested areas and habitat value.
  • To recognize the importance of the adjacent Tauranga Bay, and to build up numbers of its shrinking Blue Penguin colony, through sponsorship of the West Coast Blue Penguin Trust. The overall goal is to restore a mosaic of indigenous forest and wetland communities similar to that which existed prior to human arrival.
  • Following the completion of quarrying, leave a protected natural area at a lower topographic level that will represent a self-sufficient ecological unit.

The rehabilitation plan began in the 1980s to mitigate the visual impact of quarry operations and has since developed into a plan to improve the biodiversity of the quarry and its surroundings. The work follows four guiding principles:

  1. rehabilitation should mimic natural forest regeneration
  2. direct human contact is to be minimized
  3. rehabilitation is concurrent with quarrying operations
  4. costs must be well managed

The rehabilitation area consists of an indigenous forest, a lake, and adjacent wetlands. The land has been divided into four zones reflecting the specific ecological makeup: the coastal restoration zone, mainly farmland adjacent to Tauranga Bay; the wetland restoration zone of the planned lake and associated wetlands; the quarry restoration zone quarry slopes and areas of workings not flooded; the inland restoration zone of land adjacent to the road and inland farmland. Early in the project, a plan for successful continuous rehabilitation was developed. An onsite nursery was established to raise eco-sourced indigenous species under local conditions. This nursery is leased to a local nursery manager who provides up to 50,000 plants a year on contract, as well as growing for general sale.

In association with Lincoln University, work has focused on determining breeding and fledging success rates of the West Coast blue penguins, compared with other colonies around New Zealand and in South Australia. Holcim has provided funding for nesting boxes, predator control, and support for research into migration and breeding patterns.

The School of Forestry at Canterbury University has been involved in the project from the early stage. The university has supervised projects to assess the reestablishment of native species in the quarry environs and has presented reports on the success of the rehabilitation so far. With this in mind, Holcim recently approved a grant to Canterbury University for the study of quarry rehabilitation. These studies will serve as a basis for ongoing monitoring work and should provide a long-term appreciation of the results of the program and hopefully establish the site as an important example of rehabilitation.

Rehabilitated and regenerating bush now covers over 60ha of company land. Studies of the rehabilitation areas indicate that the restored sites are facilitating the entry of novel regenerating species, which indicates native plant species have self-seeded rather than been planted (eg. kahikitea and totora). A large difference was apparent in composition and abundance of ground active invertebrate communities in planted restoration and remnant study sites. Litter depth was found to be the key driver of invertebrate distribution. Restoration plantings have successfully provided new habitat for native biodiversity, while facilitating development of ecosystem structure and functioning. Importantly, they are increasing the connectivity between native forest remnants, enhancing the aesthetic appeal of the quarry area.

The studies also indicate that complete success has not yet occurred. The current limiting factor to progression within the planted restoration study sites appears to be the lack of full canopy cover, and subsequent development of suitable microclimatic conditions.

Some elements that have contributed to the success of this project are:

  1. Rehabilitation takes place concurrent with quarrying activities and is thus seen as part of the normal business.
  2. Involvement of community and experts. The project is a collaboration involving Holcim staff, the local community, experts, and the Department of Conservation.

Throughout the long history of the project, the following lessons have been learned.

  1. Proper planning. Holcim sought scientific input early in the process to ensure that the goals were appropriate.
  2. Ensure the first step is to create and enhance habitat.
  3. Focus on indigenous species to ensure long term viability
  4. Recognize that nature works slowly and a long-term vision is essential.
  5. Ensure the appropriate experts, community representatives and indigenous groups are involved with the project.
  6. Long-term commitment to a shared vision.