Contrasting effects of climate change on the timing of reproduction and reproductive success of a temperate insectivorous bat

We used long‐term datasets to analyse (1) the patterns of covariation between basic climatic variables (temperature and rainfall) and the timing of reproduction and reproductive success; and (2) long‐term trends in both reproductive parameters of a maternity colony of D aubenton's bats M yotis daubentonii in S outh B ohemia, C zech R epublic. The mean A pril temperature was the best predictor of the timing of reproduction. The higher the A pril temperature, the earlier the first neonates appeared. The mean date of first parturition was J une 4, but it advanced significantly by c. 11 days between 1970 and 2012. Similarly, the mean A pril temperature increased over the study period by c. 2.7° C . Between 1999 and 2012, the mean reproductive success (proportion of reproductive females) was 74%, but varied between 33% (2009) and 93% (2006). It was negatively related to M ay– J uly precipitation. Thus, reproductive success was lower in years with increased rainfall. Given the published evidence that advancement in parturition is positively related to survival of juvenile bats rising spring temperatures may have a beneficial influence on the population dynamics of D aubenton's bats. However, increased incidence of climatic extremes, such as excessive summer rainfall, may largely buffer this effect. Consequently, populations of temperate insectivorous bats may experience increasing environmental stress under continuing climate change.