Establishment of biodiversity monitoring plots within geothermal habitats, Waikato Region, 2024

Report: TR 2024/26

Authors: Chris Bycroft, Hannah Heasmen, Emily Chase, Emma Ries, Angela McQuillan, Mitchell West, Jo McQueen, Sarah Beadel – Wildlands Consultants Ltd

In 2023, Wildland Consultants reviewed the standardised monitoring protocols for measuring ecosystem integrity across New Zealand’s diverse environments, with specific consideration on geothermal ecosystem monitoring (Wildland Consultants 2023a). Geothermal habitats present a range of challenges for monitoring biodiversity which are not sufficiently accounted for by the current national monitoring framework methodology described in Bellingham et al. 2021 and Hurst et al. 2022. Monitoring geothermal vegetation presents a range of challenges: difficulty of access, high habitat diversity within sites, and habitats and species susceptible to trampling impacts. There are also many safety issues associated with heated and unstable ground, dangerous features such as mudpools, hot springs, geysers, hidden geothermal holes, dangerous geothermal streamsides, and toxic gases.

In 2023 geothermal ecosystem monitoring was reviewed, including consideration of options for implementing quantitative monitoring methods compatible with the national monitoring framework (Wildland Consultants 2023a). Previous monitoring was reviewed and challenges workshopped. Three recommendations with regard to monitoring geothermal ecosystems were made. First, methods to quantitatively measure geothermal ecosystem integrity should be added to the suite of indicators currently being monitored. Second, quantitative assessment of the integrity of geothermal habitats should be achieved by applying the methods for wetland ecosystems proposed by Bellingham et al. (2021) for geothermal wetlands; and a modification of methods proposed by Bellingham et al. (2021) for other geothermal habitats that are not dangerous. Third, a new approach to measuring vegetation structure and cover abundance using drones and 1 m2 plots could be explored to extend measurement of ecosystem integrity into areas unsafe to access on foot.

Following the 2023 review, Waikato Regional Council commissioned Wildland Consultants to prioritise and establish biodiversity monitoring of geothermal ecosystems within Protected Geothermal Systems1 and develop procedures to identify monitoring frequencies. There are 15 geothermal sites (Wildland Consultants 2023b) within the five Protected Geothermal Systems. Monitoring within Development Geothermal Systems is generally well-established through resource consent processes, although methodologies differ across sites. This report presents the process undertaken to establish monitoring within Protected Geothermal Systems, results of the monitoring and key findings, and recommendations on future monitoring including frequency. Twelve permanent monitoring plots were established within the budget and timeframe available (May – June 2024) within five sites within three Protected Geothermal Systems (Orākei Kōrako, Te Kopia and Waikite-Waiotapu-Waimangu).