In my last post I showed a chart of my TrackaTree phenology data for Wood anemones for 2014-2017. As the chart below shows, the timing of flowering of the Lesser celandines has varied less over these four years, with only 13 days between the earliest 2014 and the latest, 2016. However it is noticeable that the order of the four years has been the same for both species. It is also noticeable that peak flowering lasted for a shorter period of time in 2014 than in either 2015 or 2016. In general, though, peak flowering lasts longer for the Lesser celandines than for the Wood anemones.
Given that the timing of flowering of Wood anemones varies more than that of Lesser celandines, does one of these species always flower before the other? The answer is that it depends on exactly how you measure this. I looked separately at early flowering (first date that ten flowers are visible), and date of peak flowering (the first date at which the maximum number of flowers are visible). The results are shown in the graph below.
The blue bars show the number of days that Wood anemones reached peak flowering before Lesser celandines did. Wood anemones reached their peak flowering 16 days earlier than Lesser celandines did in 2014, five days earlier in 2015, at exactly the same time in 2016, and four days earlier in 2017.
Because I started fieldwork too late in 2014, there is no data for this year for the timing of the first ten flowers. But for 2015 the Wood anemones were four days behind the Lesser celandine, in 2016 they were at exactly the same time, while in 2017 the Wood anemones were seven days in front.
Looking back at the graphs for the two species, this supports the conclusion that the Wood anemones are more variable in the timing of their flowering than are the Lesser celandines. Does this then suggest that Wood anemones are more sensitive to variations in something (temperature, rainfall?) between the years than are the Lesser celandines?