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