Create artificial hollows and cracks in trees for roosting bats

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

Effectiveness

50%
Certainty

23%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Some bat species roost within naturally forming crevices and cavities within trees. Similar features could be created artificially in existing trees to provide roosting opportunities for bats.

A study that uses snag recruitment alongside other practices for forest restoration is described in ‘Create or restore bat foraging habitat in urban areas’.

Study locations

Key messages

One study evaluated the effects of creating artificial hollows and cracks in trees for roosting bats. The study was in Australia.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (0 STUDIES)

BEHAVIOUR (1 STUDY)

Use (1 study): One replicated study in Australia found that eight of 16 artificial hollows cut into trees for bats, birds and marsupials with two different entrance designs were used by roosting long-eared bats.

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 replicated study in 2015–2016 of 16 trees within a timber production forest in New South Wales, Australia (Rueegger 2017) found that half of the artificial hollows created in trees were used by long-eared bats Nyctophilus spp., and the design of the entrance did not have a significant effect on use. Eight of 16 artificial hollows were used by long-eared bats, including one of six hollows designed for bats and seven of 10 hollows designed for marsupials and birds, although use of the two designs did not differ significantly. Artificial hollows were created in 16 trees (33–54 mm diameter at breast height) within a forested area of 4 ha. In September 2015, one hollow (35 cm high x 9–20 cm wide and 4 m above the ground) was created in each of 16 trees using a chainsaw. A section of tree (4 cm deep) was reattached to the front of each hollow with an entrance hole either at the base (designed for bats, 38 mm diameter) or the top (designed for marsupials and birds, 38 or 76 mm diameter). Each of 16 hollows was monitored over 12–15 months in 2015–2016 with heat/motion activated cameras.
Study and other actions tested
Referenced paper
Rueegger N. (2017) Artificial tree hollow creation for cavity-using wildlife – trialling an alternative method to that of nest boxes. Forest Ecology and Management, 405, 404-412.

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
Create artificial caves or hibernacula for bats Action Link	Likely to be beneficial	4	Synopsis Link
Restore or create linear habitat features/green corridors Action Link	No evidence found (no assessment)	0	Synopsis Link
Reinstate bat roosts in felled tree trunks Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link