Diagram 1: Approximate location of the five disused mineshafts and bat tunnel at the site. The Disused Mineshaft is Shaft 1. Source: Expert report of Amy Rowles dated 1 November 2020, p 7.
6. Approximately four kilometres north of the site is a long solid rock horizontal tunnel with Eastern Horseshoe Bats and large guano deposits.
7. The Disused Mineshaft in question is 7.5m deep, with an opening at the top of the spoil mound of 4.3 x 3.7m and narrowing to a vertical rock shaft of 1.3m x 2.3m. An image of the opening of the Disused Mineshaft, taken on 28 September 2021, is at Tab 1 of this statement of facts.
8. The Disused Mineshaft contains a horizontal adit extending in a north-west direction at the base of the shaft.
9. During an inspection at dusk on 28 September 2021, Ms Rowles observed an Eastern Horseshoe Bat circling in the top section of the shaft but did not see whether it had exited from the horizontal adit. On 29 September 2021, Ms Rowles observed one Eastern Horseshoe Bat exiting and re-entering the horizontal adit.
EASTERN HORSEHOE BAT
10. The Eastern Horseshoe Bay is not listed as a threatened species under the Biodiversity Conservation Act 2016 or under its predecessor, the Threatened Species Conservation Act 1995.
11. The population of the Eastern Horseshoe Bat in the Dampier Forest is likely to engage in nightly movements to forage within a few kilometres adjacent to their roost location but also, over the course of months, to move between a network of suitable roosts, perhaps up to 30km distant. The occurrence of the Eastern Horseshoe Bat in southern NSW is constrained by the presence of subterranean roosts with suitable dimensions, such as disused mineshafts, a microclimate of high humidity and suitable foraging habitat of about two kilometres of the roost. The species depends on a network of roost sites and does not reside permanently at one roost site.
12. Populations of this species in central and southeast NSW are thought to have declined over the past few decades, however, it is not known if the population in the Dampier Forest, or southern NSW in general, is declining, stable or increasing. An image of Eastern Horseshoe Bat is included at Tab 2 to this statement of facts.
13. Trees were felled over an area of 0.2ha out of a 0.5ha exclusion zone. This had the potential to significantly increase solar radiation and increased desiccation of the forest stand. Solar radiation on the mouth of the mineshaft from the North would have increased due to the tree removal in this direction, however, this would have been lessened by trees within 16m of the shaft being retained. This has the potential to impact the temperature and wind profile within the exclusion zone and alter the microclimate of the Disused Mineshaft. In light of the depth of the horizontal adit from the surface and measurements taken on 28-29 September 2021 (by an ecologist retained by the defendant) of the temperature and humidity at the base of the shaft, any impact on the vegetation is not likely to change the temperature and humidity of the horizontal adit to any significant degree.
14. Noise and possible vibration arising from logging machinery and tree felling had the potential to disturb Eastern Horseshoe Bats roosting in the Disused Mineshaft by arousing Eastern Horseshoe Bats from their daytime torpor, causing bats to fly around or exit the roost during the daytime, thereby reducing their energy levels and increasing predation risk from diurnal bird predators. There was potential for collapse of the roost, obstruction of the roost entrance from vegetation or a change in vegetation structure caused by the felling, but there is no evidence that any of these occurred.
15. Exclusion zones surrounding subterranean roost entrances serve to maintain the microclimate within the roost by preventing changes to the forest profile. This is significant for the Eastern Horseshoe Bat, compared to other cave roosting bat species in the region, for which very high humidity, typically higher than 85%, is considered essential for the survival of the species. It is not possible to know if the microclimate of the mineshaft was altered to some degree as a result of the clearing (without a before and after experiment or study).
ENVIRONMENTAL HARM: s 13.12(1)(a)
16. It is likely the logging of trees on 2 May 2019 in the exclusion zone around the Disused Mineshaft caused some harm to any Eastern Horseshoe Bats that were roosting in the adit at the time, due to the noise and vibration in the exclusion zone from the tree felling and use of machinery. The extent of harm is considered to be minor due to:
a. the time of year that the clearing occurred which was not during winter or the maternity season for any microbat species, thus any energy loss for any bats flying in, around or out of the roost, would not have been significant due to suitable weather conditions for foraging, most likely occurring at night;
b. the short length of time the disturbance took place;
c. the presence of other known roost sites within 150m of the Disused Mineshaft providing alternative roosting sites; and
d. the immediate area around the roost entrance remaining intact.
17. A loss of dozen or more bats would represent a potentially significant incremental increase in overall mortality rates for the local population. There is no evidence that any bats were lost.