Punakaiki Coastal Restoration Project: A case study for a consultative and multidisciplinary approach in selecting indicators of restoration success for a sand mining closure site, West Coast, New Zealand

Abstract

The Punakaiki Coastal Restoration Project (PCRP) is a case study in partnership and collaboration, which outlines how a consultative approach to mine closure can deliver shared benefits and create new endeavors that advance conservation, knowledge of biodiversity, and a broader understanding of the role of multi-sector partnerships. In 2000, Rio Tinto acquired 114 ha of coastal land at Punakaiki on New Zealand's South Island that had been the focus of a proposed mineral sand development, culminating in pilot-scale mining and processing by Westland Ilmenite Limited (WIL, part of North Ltd.), in the early 1990s. The site had been in care and maintenance from 1994. Rio Tinto instigated a process to ensure its approach to post-closure was developed and managed to meet its goal of contributing to sustainable development. Though much of the land has been cleared for pasture, the area is of high conservation value. The Punakaiki Coastal Restoration Project (PCRP) was established in 2009 to enhance the revegetation of the sand plain forest on land adjacent to the Nikau Scenic Reserve that had been previously mined and farmed. To develop and test the indicators of restoration success, we performed interdisciplinary research in a) floral and faunal inventories and monitoring to determine characteristics of forest and disturbed environments at the species and community level, with a focus on the transition of these characteristics during restoration; b) pedology and soil chemical analysis was completed to identify potential variables that may influence the restoration of flora and faunal communities at the site. Seven transects were established across the site: each comprising 3 monitoring plots (mature forest, unplanted and restored). Several significant ecological indicators were identified across these three monitoring plots. The future trajectory of restoration success will be determined by canopy closure and subsequent colonisation and recruitment of additional species, with epiphytes and plant associations being particularly critical. Soil profile pits were dug in each plot (21 in total) and the soil profile was described and sampled for chemical analyses. This monitoring and interdisciplinary research programme has informed the restoration process on its trajectory from post-mining to farmed pasture to mature forest, beyond the initial establishment of 130,000 trees for 5 years. A multi-dimensional approach linking changing soil, vegetation and faunal communities, beyond a baseline survey and onward monitoring, provides an example of the best practice in restoration ecology. Future management of this site presents an opportunity to develop ecological, educational, and recreational values which are potentially beneficial to the local community through tourism. This research signals a paradigm shift in creative conservation through integrative restoration ecology that includes the floristic, faunal, geological and pedological components. This approach is readily transferable and could constitute a new standard for the next generation of restoration projects and national parks.