Change in timing of central tendency
This plot is based on a figure in the 2004 Edwards and Richardson Nature paper in which the timing of central tendency was used to estimate a change in timing by calculating the difference between the start and end timing values in a time series. In that case, the data considered plankton data from the continuous plankton recorder (CPR) time series. In this case, we are considering a different time series spanning from 1984-2010 with a 4 year gap.
A negative difference between the start of the time series (1984) and 2010 indicates that the phenological timing of a taxa is anticipated or their season is starting earlier. A positive difference is interpreted that the species season is delayed or later.
The taxa considered here have been evaluated at species level, but for the sake of this plot are depicted into plankton classes. In total there are 30 taxa (in this study) with a distinct unimodal season that include phytoplankton (n=14 species) and zooplankton (n=16).
Edwards, M., and A. J. Richardson. 2004. Impact of climate change on marine pelagic phenology and trophic mismatch. Nature 430: 881–884.