Create or maintain small dams to provide foraging and drinking habitat for bats
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Large dams are likely to have a negative impact on bats due to habitat loss and fragmentation (e.g. Rebelo & Rainho 2009). However, small dams along rivers can create pools and reservoirs within natural habitats, which may provide foraging and drinking resources for bats. For interventions that involve creating other types of water sources, see ‘Create artificial water sources’.
Rebelo H. & Rainho A. (2009) Bat conservation and large dams: spatial changes in habitat use caused by Europe’s largest reservoir. Endangered Species Research, 8, 61–68.
Supporting evidence from individual studies
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