Individual study: The use of bat gates at abandoned mines in Colorado
Navo K.W. & Krabacher P. (2005) The use of bat gates at abandoned mines in Colorado. Bat Research News, 46, 1-8
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Install and maintain gates at mine entrances to restrict public access
A before-and-after study in 1991–2004 at 47 gated abandoned mines in forested areas of Colorado, USA (Navo & Krabacher 2005) found that 43 of 47 mines with gates of various designs continued to be used by eight bat species up to 12 years after installation. None of 43 mines with full gates with or without culverts were abandoned by bats. Three mines with ladder gates and one mine with a culvert ladder gate were abandoned by bats. Four types of gate were evaluated, all with bar spacings of 150 mm. Traditional gates allowed access to bats across the whole gate, ladder gates allowed access to bats at the centre only, and both types of gate were also constructed in metal culverts where mine entrances were too unstable to anchor the gate itself. Each of 47 mines were surveyed 2–10 times in 1991–2004 using multiple methods (catching, visual counts and infra-red motion detectors).
(Summarised by Anna Berthinussen)