Data from: Climate warming: a loss of variation in populations can accompany reproductive shifts

The most documented response of organisms to climate warming is a change in the average timing of seasonal activities (phenology). Although we know that these average changes can differ among species and populations, we do not know whether climate warming impacts within-population variation in phenology. Using data from five study sites collected during a 13-year survey, we found that the increase in spring temperatures is associated with a reproductive advance of 10 days in natural populations of common lizards (Zootoca vivipara). Interestingly, we show a correlated loss of variation in reproductive dates within populations. As illustrated by a model, this shortening of the reproductive period can have significant negative effects on population dynamics. Consequently, we encourage tests in other species to assess the generality of decreased variation in phenological responses to climate change.Phenology of the common lizard on five study sitesThis file includes data collected on the phenology of the common lizard on five sites (variable SITE) of the Mont-Lozère. TEMPERATURE is the mean of daily maximum air temperature in June (°C). Parturition dates are described by the mean of the time interval since July 1 (MEAN in days) and its standard deviation (SD). The file also reports the sample size N (number of litters per site and year), the coefficient of variation CV (SD divided by the mean date), the SKEWNESS and KURTOSIS of the frequency distributions of parturition dates.Experimental testThis file includes data on the experiment performed in 2005. This experiment tested the influence of temperature during gestation on the parturition date of the common lizard. The variable DATE is the number of days since July 1, IDENTITY is the female identity, and TEMPERATURE reports the three experimental groups: A = warm group, B = intermediate-heat group, C = cold group