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Providing evidence to improve practice

Individual study: Effects of a cave gate on emergence patterns of colonial bats

Published source details

Ludlow M.E. & Gore J.A. (2000) Effects of a cave gate on emergence patterns of colonial bats. Wildlife Society Bulletin, 28, 191-196


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Install fencing around cave entrances to restrict public access Bat Conservation

A controlled, before-and-after study in 1994–1996 at one cave on a forested limestone ridge in north Florida, USA (Ludlow et al 2000) found that replacing a steel bar gate with a fence resulted in more southeastern myotis bats Myotis austroriparius and gray myotis bats Myotis grisescens emerging from the cave entrance. More bats emerged from the cave entrance when a fence was installed (average 1,517 bats/month, 48% of total bats emerging) instead of a steel bar gate (306 bats/month, 8%).  The number of bats emerging from a second ungated open entrance to the cave decreased after the gate was replaced with a fence (from 3,609 to 1,651 bats/month). The cave gate consisted of steel bars 13 mm in diameter spaced 100 mm apart in one direction and 465 mm in the other. Before removal of the gate a 2.2 m high chain-link fence was erected 6–8 m from the cave entrance. Emerging bats were counted monthly at the gated entrance and the open entrance for one year before and one year after the cave gate was removed and replaced with a fence (August 1994 to July 1996).

(Summarised by Anna Berthinussen)

Install and maintain cave gates to restrict public access Bat Conservation

A before-and-after study in 1994–1996 at one cave on a forested limestone ridge in north Florida, USA (Ludlow & Gore 2000) found that a steel bar gate across the cave entrance resulted in fewer southeastern myotis bats Myotis austroriparius and gray myotis bats Myotis grisescens emerging than when the gate was replaced with a fence.  Fewer bats emerged from the cave entrance when it had a steel bar gate across it (average 306 bats/month, 8% of total bats emerging from cave) than when the gate was replaced with a fence (average 1,517 bats/month, 48% of total bats emerging).  The number of bats emerging from a second un-gated entrance to the cave decreased after the gate was replaced with a fence (from 3,609 to 1,651 bats/month). The cave gate consisted of steel bars 13 mm in diameter spaced 100 mm apart in one direction and 465 mm in the other. Before removal of the gate a 2.2 m high chain-link fence was erected 6–8 m from the cave entrance. Emerging bats were counted monthly at the open entrance and gated entrance for one year before and one year after the cave gate was removed (August 1994 to July 1996).

(Summarised by Anna Berthinussen)