Ambient solar radiation data
The principal driver of p CA is thought to be variations in UV-B radiation, however as UV-B radiation is difficult to differentiate from other incoming radiation (e.g. PAR, UV-A) using only one location, we used solar radiation measurement (W/m2) as a proxy for differences in the incoming solar radiation in inter-annual and inter-specific variability study from the IDAWEB meteorological data archive provided by MeteoSwiss (https://gate.meteoswiss.ch/idaweb/more.do). The measurement station in Geneva is located in Cointrin (N 46°15’, E 6°08’) which is approx. 2 km from the botanic garden. We used daily mean global radiation (W/m2) data from June 1st 2012 to May 31th 2014 (Fig. 1 a). The daily measurements from January 1st 2004 to December 31th 2014 were summarised into monthly mean solar radiation and averaged across all years to calculate monthly anomalies (Fig. 1 b). We summarised total solar radiation (W/m2) 28 days and 56 days prior to each collection date, May 14th 2013 and May 26th 2014. The following R packages were used to obtain these data: tidyverse (Wickham, 2017), scales (Wickham, 2016), lubridate (Garrett and Hadley, 2011) and for plotting we used ggplot2 (Wickham, 2009), grid (R Core Team, 2017) and cowplot (Wilke, 2016).
Results