Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 83 8.5.3 Pest Control to Address Uncertain Residual Effects on Archey’s Frogs This assessment and Dr Ussher’s assessment (RMA Ecology, 2022) indicate that, under a worst-case scenario, there could be residual adverse direct or indirect impacts on Archey’s and Hochstetter’s frogs within the Wharekirauponga Project Area after avoidance and mitigation have been applied. There is uncertainty about the likelihood and magnitude of effects on native frogs, but we have taken a conservative approach to offsetting these effects to achieve no net loss of frogs. The primary outcome of this assessment was the development of a wide-scale pest animal management plan (WPAMP, Boffa Miskell 2022) to benefit native frogs and other fauna within the 314 ha surface area exposed to vibration levels >2 mm /sec vibration levels (above which impacts on native frogs are uncertain). The WPAMP was designed so that in the very unlikely event that all frogs die within the 314 ha area of WUG subject to surface vibration greater than 2 mm /sec49, the potential benefits of undertaking intensive pest control would be more than sufficient to balance losses that may occur under the most pessimistic scenario of adverse effects on Archey’s frogs (RMA Ecology, 2022). The programme is divided into two different areas. One encompasses the potential vibration impacted area (314 ha) and an adjacent area of high-quality frog habitat (319 ha) outside of the potentially impacted area. This combined 633 ha area (Wharekirauponga Animal Pest Management Area, WAPMA) will undergo an intensive pest control regime designed to supress rats and mice as predators of native frogs and reverse the habitat destruction caused by pigs (Figure 14). Control of goats, feral cats, possums, wasps and mustelids is also proposed as part of the PAMP. A second area, the immediately adjacent Otahu Ecological Area (approximately 700 ha) will also have an enhanced pest control regime put in place as part of the Waihi North Biodiversity Project (Section 8.6.4, The Ecology Company, 2021). The pest control programme is expected to benefit the resident frog population as well as providing benefits by the habitat enhancement that comes from pest control (especially from pig removal). Extensive pest control will have benefits for other native species, including lizards, birds and invertebrates in addition to Archey’s and Hochstetter’s frogs (Byrom et al, 2016, Monks et. al 2014, Watts et. al 2020). Integrated large scale pest control as proposed here is expected to result in population recovery of forest bird species (i.e. increased abundance, improved nesting success and potentially increased species richness). Lizard species are also expected to benefit from the proposed pest control, but as the size of lizard populations is apparently low, may take longer to recover. Wide-scale pest management in the areas proposed has the additional benefit that they buffer each other, reducing the pest incursion rate and providing a large, continuous protected area, delivering further substantial benefits to indigenous biodiversity. With effective pest control in place, the WPAMP anticipates that a level of population enhancement of Archey’s frogs could be expected of between 2.3 and 4 times the current population over a period of 3-4 years (based on population gains observed elsewhere) (detailed in Boffa Miskell (2022c)). As such, we consider that wide-scale, comprehensive pest animal control is an appropriate biodiversity offset for the potential residual effects associated with WUG. 49 i.e. more than the levels at which they have been recorded along roadside margins in the Coromandel, and at Golden Cross
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