Simulating randomly selected (unbiased) phenological
snapshots from pre-defined populations
For each species, we then generated simulated specimens by: (1) randomly
selecting an individual within each population and (2) selecting a
random DOY within its individual-level flowering period that emulated
the phenological snapshot provided by real herbarium specimens.
Specifically, using the distribution of peak flowering dates of each
population, we selected an individual at random. From its peak flowering
date, we then obtained onset and termination dates by subtracting (for
flowering onset) or adding (for flowering termination) half the
individual’s flowering duration for that species to the sampled date of
peak flowering (Fig. 1b). To simulate a phenological snapshot for that
individual, we then randomly selected a DOY between the onset and
termination of that individual’s flowering period. As a result, the
simulated datum represented a simulated herbarium specimen generated
accounting for uncertainty in both the timing of the individual relative
to its source population, and in the timing of the collection relative
to the onset and termination of that individual’s flowering period. This
procedure was repeated across all locations for each simulated species,
generating 1000 data points (i.e., simulated specimens or phenological
snapshots) per species.