Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 49 6.2.5 Bats Noise Bat populations (if present) within Coromandel Forest Park may respond to a localised increased noise environment with avoidance if the noise is within a frequency that they can perceive. Previous studies on road traffic impacts on long-tailed bats showed that bat activity declines rapidly as traffic rates increase at night (NZTA, 2017). The extent of these impacts on a population level was not explored. Similarly, a study on long-tailed bat activity near New Zealand highways show a negative relationship between bat activity and night-time traffic volume for bat detector units on a highway, whereas bat activity recorded on distant bat detector units had no discernible relationship with night-time traffic volume (Borkin et al. 2019). It is unclear whether the response by bats was a result of increased noise or lighting from higher traffic volumes. Vibration Vibration effects on bats are poorly studied, internationally and in New Zealand. Bats are highly mobile and would be able to relocate in the event that vibrations were distressing. We further consider that vibrations will be barely perceptible in an arboreal roost. 6.2.6 Native Birds Noise New Zealand forest bird species are highly vocal and highly mobile and may display aversion behaviours if noise associated with construction, helicopter activity or ventilation fans is disruptive. However, international studies indicate that birds do soon habituate to regular disturbance, particularly continuous, steady noise as is expected from ventilation fans (Harbrow et. al. 2011). The types of behaviours that birds may display to compensate for elevated background noise levels includes changing the strength, nature, and frequency of calls and foraging birds increasing vigilance in response to the perceived reduction in awareness of predators. Vibration New Zealand forest bird species are highly mobile, and for species recorded in Wharekirauponga catchment previously, all nest in trees. Birds are most sensitive during the nesting season (from laying to fledging), but it is expected that vibrations will be barely perceptible in an arboreal nest. Natural disturbance (e.g. high winds) are more likely to impact nesting success. 6.3 Willows Road Farm 6.3.1 Approach The ecological values of the Willows Road Farm are low, with negligible vegetation values and low fauna values. The potential ecological effects associated with construction and operation of the tunnel and surface infrastructure are well-understood. Engineering interventions (e.g. noise bunds) have been incorporated into the design where appropriate to reduce potential effects. This section describes the potential ecological effects of the WNP on the Willows Road farm site (including the south-eastern extent of CFP, where appropriate). These potential effects include
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