Minimize noise levels within caves

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

Effectiveness

40%
Certainty

21%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Noise may disturb bats within caves, causing arousal during hibernation or roost abandonment. Noise levels may be minimised by restricting the number or timing of tourist visits or by asking tourists to remain quiet during tours. See also ‘Impose restrictions on cave visits’.

Study locations

Key messages

One study evaluated the effects of minimizing noise levels within caves on bat populations. The study was in the USA.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (0 STUDIES)

BEHAVIOUR (1 STUDY)

Behaviour change (1 study): One controlled study in the USAfound that experimental cave tours with groups that did not talk resulted in fewer bat flights than when groups did talk, but talking did not have an effect on the number of bat movements.

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 controlled study in 1997–1998 in one cave in Arizona, USA (Mann et al 2002) found that experimental cave tours with groups that did not talk resulted in fewer take-offs and landings by a roosting cave myotis Myotis velifer colony than when groups did talk, but talking did not have a significant effect on overall colony activity. Bats had fewer take-offs and landings when groups did not talk (take-offs: average 13; landings: average 12) than when all members of the group talked (take-offs: average 16; landings: average 14). Overall activity of the colony (all bat movements) was similar when groups did not talk (average 59% of colony active) or when all members of the group talked (62%). A colony of 1,000 cave myotis bats roosted in a large cluster within one room of the cave. Experimental tours were carried out through the room with five replicates of each of 24 treatment combinations. Treatments included voice intensity (no people talking, all members of group talking), light intensity and colour (no light, low intensity white light, full red light, full white light), and size of tour group (0, 1–3 or 6–8 people). A total of 120 experimental cave tours were carried out between April and September in 1997 and 1998. Bat behaviour was observed with a night-vision video camera and infrared lights.
Study and other actions tested
Referenced paper
Mann S.L., Steidl R.J. & Dalton V.M. (2002) Effects of cave tours on breeding Myotis velifer. Journal of Wildlife Management, 66, 618-624.

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

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bat Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Impose restrictions on cave visits Action Link	Likely to be beneficial	4	Synopsis Link
Restore and maintain microclimate in modified caves Action Link	No evidence found (no assessment)	0	Synopsis Link
Minimize alterations to caves for tourism Action Link	No evidence found (no assessment)	0	Synopsis Link