An investigation of the impact of development projects on bat populations: Comparing pre- and post-development bat faunas

Published source details Aughney T (2008) An investigation of the impact of development projects on bat populations: Comparing pre- and post-development bat faunas. Bat Conservation Ireland report.
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This study is summarised as evidence for the following.

	Action	Category
	Relocate access points to bat roosts within developments Action Link
	Retain existing bat roosts and access points within developments Action Link
	Change timing of building work Action Link
	Provide bat boxes for roosting bats Action Link

Relocate access points to bat roosts within developments

A before-and-after study in 2004–2008 of one building renovation in Ireland (Aughney 2008) found that after relocating the access points to a bat roost within an attic during renovations, fewer brown long-eared bats Plecotus auritus used the roost and no bats were observed flying through the new access points. Before the renovations, 19 and eight brown long-eared bats were recorded exiting the roost through two original access points. After the renovations, no bats were observed exiting through two relocated access points and the number of droppings found inside the attic (<100) indicated that fewer bats were using the roost than before the renovations (number not reported). The building was a 19^th century brick house. During renovation work, two bat access points consisting of angled slats (‘louvres’) were installed in the roof in different locations to the original bat access points. Renovations were completed in early 2007. Emergence counts were carried out once in June 2004 before the renovations, and once in August 2008 after the renovations. An internal inspection was carried out in October 2008.

(Summarised by: Anna Berthinussen)
Retain existing bat roosts and access points within developments

A before-and-after study in 2004–2008 of one building renovation in Ireland (Aughney 2008) found that retaining four existing bat access points, along with restricting the timing of roofing work, resulted in similar numbers of brown long-eared bats Plecotus auritus using a roost within an attic before and after renovations. Fifteen brown long-eared bats were counted roosting in the attic space of the building before the renovation work. After the renovation work, sixteen brown long-eared bats were recorded exiting the roost through the retained access points. The building was an 18^th century Georgian house that had the roofing felt and roof slates replaced. Original access points to the roost within the attic of the building were retained by installing four vents in the ridge tiles. The renovations were completed outside of the maternity season (date not reported). The attic was surveyed once in 2004 before the renovations, and once with an emergence survey in September 2008 after the renovations.

(Summarised by: Anna Berthinussen)
Change timing of building work

A before-and-after study in 2004–2008 of one building renovation in Ireland (Aughney 2008) found that carrying out roofing work outside of the maternity season, along with retaining existing bat access points, resulted in a similar number of brown long-eared bats Plecotus auritus using a roost within an attic before and after renovations. Fifteen brown long-eared bats were counted roosting in the attic space of the building before renovation work. After the renovation work, sixteen brown long-eared bats were recorded exiting the roost through the retained access points. The building was an 18^th century Georgian house that had the roofing felt and roof slates replaced. Original access points to the roost within the attic of the building were retained by installing four vents in the ridge tiles. The renovations were completed outside of the maternity season (date not reported). The attic was surveyed once in 2004 before the renovations, and once with an emergence survey in September 2008 after the renovations.

(Summarised by: Anna Berthinussen)
Provide bat boxes for roosting bats

A study in 2004–2008 of five road developments and three residential and commercial developments in Ireland (Aughney 2008) found bats of four species occupying 33 of 150 bat boxes (22%) and bat droppings in 77 of 150 bat boxes (77%) across all eight sites. Overall, 91 individual bats were recorded occupying bat boxes, including soprano pipistrelles Pipistrellus pygmaeus (68), common pipistrelles Pipistrellus pipistrellus (17), Leisler’s bats Nyctalus leisleri (5) and Daubenton’s bat Myotis daubentonii (1). Bat droppings of Pipistrellus spp. were recorded in 62 bat boxes, Leisler’s bat droppings were recorded in 12 bat boxes and Myotis spp. droppings were recorded in three bat boxes. Bat boxes were either woodcrete (137 bat boxes: either Schwegler designs 1FD, 1FF, 1FN, 1FS, 2F, 2FN or 2F-DPF), wedge-shaped wooden bat boxes (5 boxes) or standard wooden bat boxes (8 boxes). At each of eight sites, 3–33 bat boxes were installed in 2002–2008 as mitigation for habitat loss. Each of the 150 bat boxes was checked once in June, October, or November 2008.

(Summarised by: Anna Berthinussen)