Study by Jeremy Froidevaux shows bat population is on the increase due to climate change

Since the middle of the 20th century, populations of many bat species have suffered a severe decline all over Europe. However, a recent study published in Biological Conservation (Barlow et al. 2015, DOI: 10.1016/j.biocon.2014.11.022 ) which investigated bat population trends between 1997- 2012 revealed a significant increase of several bat populations in the United Kingdom.

To our knowledge, factors driving this recovery have not yet been assessed. We therefore investigated which extrinsic (i.e. climate, landscape characteristics, Agri-environment schemes) and intrinsic (i.e. density dependence, Allee effect) factors were the most likely to explain the population recovery. To test our hypotheses, we used the greater horseshoe bat (R. ferrumequinum) as a case study. This species of special conservation concern is an interesting model given that we know from the literature that (i) climate influences some demographic parameters; (ii) this species requires high-quality foraging habitats and (iii) females R. ferrumequinum display strong sociality behaviour. We based our analyses from a dataset spanning the period 1997-2014 (18 years).

Overall, this study showed that the recent increase observed is mainly due to climate change. We found a strong association between population growth and changes in spring temperatures and precipitation. We also emphasized that R. ferrumequinum colony size was significantly related to landscape characteristics supported by the current Agri-environment schemes. Moreover, we highlighted that light pollution has a strong negative effect on the size of bat colonies.

Jeremy Froidevaux, SWBio DTP student

Paper: Factors driving population recovery of the greater horseshoe bat (Rhinolophus ferrumequinum) in the UK: implications for conservation by  J. Froidevaux, K. Boughey, K. Barlow and G. Jones in Biodiversity and Conservation.