Effects of gates on the nighttime use of mines by bats in northern Idaho

Published source details Derusseau S.N. & Huntly N.J. (2012) Effects of gates on the nighttime use of mines by bats in northern Idaho. Northwestern Naturalist, 93, 60-66.
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This study is summarised as evidence for the following.

	Action	Category
	Install and maintain gates at mine entrances to restrict public access Action Link

Install and maintain gates at mine entrances to restrict public access

A replicated, before-and-after study in 2002–2004 at five pairs of abandoned mines in northern Idaho, USA (Derusseau & Huntly 2012) found that installing gates resulted in fewer bats and fewer bat species entering the mines. Fewer bats entered mines after gates were installed with an overall decrease of 65% across all gated mines (before: average 29 bat entries; after: 10 bat entries). The number of bats entering five ungated mines increased by 45% over the same period (‘before’: 20 bat entries; ‘after’ 32 bat entries). Fewer bat species entered the mines after gates were installed (before: average 2.3 bat species; after: 1 bat species), but no change was observed at ungated mines (‘before’: 2 bat species; ‘after’: 1.8 bat species). Gates were installed at five of 10 mines in 2002 and 2003. Gates had vertical supports (10 x 10 x 1 cm iron) and horizontal bars (10 x 10 cm angle iron) with gaps of <14.6 cm. Each of five pairs of mines was surveyed twice in July–August in two consecutive years in 2002–2004 (before and after gating). One mist net survey and one video survey were carried out at the mine entrance of each site/year.

(Summarised by: Anna Berthinussen)