Evidence to help practice
An updated bat ‘synopsis’, launched by Conservation Evidence, looks at the evidence for 190 ways to conserve bats. The bat synopsis gathers, organises, and summarises studies on the effectiveness of different ways to conserve bats, from bat boxes to legal protection, and is free to read or download from the Conservation Evidence website. The original bat synopsis was published in 2013, and updates are expected to be regular from hereon in, to incorporate new knowledge. For those unfamiliar with Conservation Evidence, it is a longstanding project to collect and summarise the evidence for what works – and what doesn’t work - to conserve all species, and all habitats, globally. It makes this information freely available, to support conservationists of all sorts to make informed decisions about what solutions to pick.
The original bat synopsis found 101 studies published before the end of 2012; the update has 173 papers published by the end of 2017 – for the first time also including studies originally published in Spanish and Portuguese. This adds substantially more information on the effectiveness of ways to conserve bats. Studies are included if they test an action that could be put in place for conservation, and have a measured outcome on bats.
Bats in Australasia
There are studies from Australia tackling several conservation actions, including creating artificial hollows in trees, leaving riparian buffers in logged habitat, and, of course, putting up bat boxes. These found some promising results, for example half of the artificial hollows created in trees in New South Wales were used by Nyctophilus species, opening up the possibility of an effective way to conserve bats in timber producing forests. Researchers in New South Wales and Western Australia also found high levels of bat activity and species richness in riparian buffers within logged forest, indicating that this could be a way to maintain connectivity. The three bat box studies from Queensland and Victoria found mixed results, with some species using boxes and others not; Gould’s long-eared bats (Nyctophilus gouldi) used boxes, as did Gould’s wattled bat (Chalinolobus gouldii), lesser long-eared bats (Nyctophilus geoffroyi), large forest bats (Vespadelus darlingtoni), southern forest bats (Vespadelus regulus) and eastern false pipistrelles (Falsistrellus tasmaniensis).
Over in New Zealand, eradicating invasives was an important topic of research; a study found that controlling rats increased the survival probabilities of bats in three long-tailed bat (Chalinolobus tuberculatus) colonies, and colonies than were declining started to increase when rats were poisoned. Translocating bats to predator free areas, however, might not be an effective solution. Another study in New Zealand found that translocating lesser short-tailed bats (Mystacina tuberculata) did not go well; the bats were translocated to an island but eight months later, the bats were balding with infected ears, and were subsequently returned to captivity.
Unfortunately no studies were found from elsewhere in Australasia, highlighting that some countries are much better studied than others. No studies were found from Australasia on other important concerns for the region, such as rehabilitating orphan or injured bats, where the data are predominantly from Europe; this is likely due to the inclusion criteria for Conservation Evidence which requires numerical data on outcomes for bats, which may not currently be routinely collected or published. Data on how injured Australasian bats fare in captivity would be a useful addition to the synopsis, and as the bat synopsis is likely to be regularly updated from hereon in, could be rapidly incorporated if made publicly available.
Climate change is of course another huge concern for Australasia’s bats. While there have as of yet not been any studies on ways to, for example, reduce temperatures at flying fox camps, studies show that bats take as readily to artificial water sources as to natural ones, which could guide adaptation strategies; while captive breeding, which could be used to keep species going in appropriate temperatures, had mixed results depending on the species. Bats in Spain benefitted from alterations to their artificial roosts which lowered the internal temperatures, helping them to cope with the severe heatwaves suffered in the country. If researchers test ways to cool down flying fox camps – for example by building shading walls, or setting up sprinkler systems – then these will be included in future updates; but ultimately, huge emissions cuts are needed to stop temperatures from escalating.
Add your own evidence
Overall, this synopsis is the most comprehensive guide on the evidence for bat conservation methods globally, and should be a useful addition to the work of bat conservationists and researchers. It is always great to expand the synopsis and add new papers, especially as this synopsis will now be regularly updated. The synopsis authors will scan a wide range of academic journals and NGO/government reports for tests of interventions, but the project also has a dedicated journal where non-academics can publish. We’d love to see the next edition having more evidence for all actions, helping conservationists to make informed choices on bat conservation.