Action Synopsis: Bat Conservation About Actions

Create or maintain small dams to provide foraging and drinking habitat for bats

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects of maintaining small dams as foraging and drinking habitat for bats on bat populations. The study was in Portugal.



  • Abundance (1 study): One replicated, site comparison study in Portugal found that reservoirs created using small dams had greater activity (relative abundance) of four bat species than the streams feeding into them.


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

  1. A replicated, site comparison study in 2011 at five dams in northeast Portugal (Hintze et al 2016) found that dam reservoirs had greater foraging and drinking activity of four bat species than the streams feeding into them. The bat species were common pipistrelle Pipistrellus pipistrellus, Kuhl’s pipistrelle Pipistrellus kuhlii, Daubenton’s bat Myotis daubentonii and European free-tailed bat Tadarida teniotis (data reported as statistical model results). Mixed results were reported for six other bat species, but numbers were too low for statistical analysis. Dam reservoirs varied in size from 50,000 to 280,000 m2. All streams had annual average flow rates of 100–300 mm and similar riparian vegetation. At each of five dams, bat activity was recorded using bat detectors at four sampling points (the upstream and downstream sides of both the dam and stream). Each point was randomly sampled on three nights (for 3 h from sunset) between July and October 2011 with one stream and one dam point sampled simultaneously.

    Study and other actions tested
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?

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Bat Conservation

This Action forms part of the Action Synopsis:

Bat Conservation
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