Control invasive predators

Overall effectiveness category Likely to be beneficial
Number of studies: 1
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How is the evidence assessed?

Effectiveness

80%
Certainty

40%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Introduced predators such as rats, feral cats and snakes can threaten bat populations. For example, the brown tree snake Boiga irregularis which invaded Guam in the 1950s, was responsible for the extermination of two bat species.

Study locations

Key messages

One study evaluated the effects of controlling invasive predators on bat populations. The study was in New Zealand.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Survival (1 study): One replicated, before-and-after study in New Zealand found that controlling ship rats resulted in increased survival probabilities for female long-tailed bats.

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 replicated, before-and-after study in 1993–2015 in a rainforest in Eglinton Valley, New Zealand (O'Connell et al 2017) found that ship rat Rattus rattus control resulted in increased survival probabilities of female bats within three long-tailed bat Chalinolobus tuberculatus colonies. Average annual survival probabilities for both adult and juvenile female bats were higher in years with rat control (adult female: 0.82; juvenile female: 0.76) than without (adult female: 0.55; juvenile female: 0.55). Population trends were positive for all three bat colonies when rats were controlled, and negative for when rats were not controlled (data reported as statistical model results). Rats within the roosting ranges of all three bat colonies were poisoned using bait stations in 2006–2009 following high beech Nothofagaceae spp. seedfall and an increase in numbers. Bats were captured annually during the breeding season over 22 summers in 1993–2015 (average 6–8 captures/colony/year). Mark-recapture data were used to calculate survival probabilities.
Study and other actions tested
Referenced paper
O'Donnell C.F.J., Pryde M.A., van Dam-Bates P. & Elliott G.P. (2017) Controlling invasive predators enhances the long-term survival of endangered New Zealand long-tailed bats (Chalinolobus tuberculatus): Implications for conservation of bats on oceanic islands. Biological Conservation, 214, 156-167.

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
Control invasive predators Action Link	Likely to be beneficial	1	Synopsis Link
Use collar-mounted devices on cats to reduce predation of bats Action Link	No evidence found (no assessment)	0	Synopsis Link
Control invasive plant species Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link