Maintain microclimate in closed/abandoned mines

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

45%
Certainty

20%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Closing mines and physically obstructing mine entrances can alter the internal microclimate and make conditions unsuitable for roosting bats. Adverse impacts on airflow and water drainage should be avoided. For a similar intervention, see ‘Restore and maintain microclimate in modified caves’. See also ‘Install and maintain cave gates to restrict public access’ for a study in which a stone wall and gate influenced the microclimate of a cave with an effect on hibernating bats.

Study locations

Key messages

One study evaluated the effects of maintaining the microclimate in an abandoned mine on bat populations. The study was in the USA.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Abundance (1 study): One before-and-after study in the USA found that modifying the microclimate of an abandoned mine by closing a man-made entrance resulted in a greater number of bats hibernating within the mine.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A before-and-after study in 2004–2007 at one mine in Southern Illinois, USA (Carter & Steffen 2010) found that modifying the microclimate within an abandoned mine by closing a human-made entrance resulted in an increase in the number of hibernating bats, including Indiana bats Myotis sodalis. Before the entrance was closed, <500 bats were counted hibernating in the mine and internal temperatures varied widely during the hibernation period (-2–18°C). After the entrance was closed, internal temperatures were more stable (11-13°C), and more bats hibernated within the mine (one year after: 1,500 bats; two years after: 2,500 bats). In summer 2005, a culvert with a door (1.2 m wide) was built into the horizontal human-made entrance shaft and the rest of the entrance was filled in. Three other entrances to the mine were left open. Hibernating bats were counted within the mine in 2004 before the entrance was closed, and in 2006 and 2007 after the entrance was closed.
Study and other actions tested
Referenced paper
Carter T.C. & Steffen B.J. (2010) Converting abandoned mines to suitable hibernacula for endangered Indiana bats. Pages 205-213 in: K.C. Vories, A.H. Caswell & T.M. Price (eds.) Protecting threatened bats at coal mines: A technical interactive forum. Department of Interior, Office of Surface Mining, Coal Research Center, Southern Illinois University, Carbondale.

Please cite as:

Berthinussen, A., Richardson O.C. and Altringham J.D. (2021) Bat Conservation: Global Evidence for the Effects of Interventions. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Bat Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Relocate bats from reclaimed mines to alternative subterranean roost sites Action Link	No evidence found (no assessment)	0	Synopsis Link
Install and maintain gates at mine entrances to restrict public access Action Link	Trade-off between benefit and harms	9	Synopsis Link
Restore bat foraging habitat at ex-quarry sites Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link