Figure 2 Caption:
Comparison of model parameters for onset (panels A, B, C) and termination (panels D, E, F) dates as a function of latitude. Panels A and D show latitude coefficients for 22 species onset and termination phenology. Values extracted from Fric et al. (2020) Supplemental Table 2 using regression of residuals against latitude, corrected for year and altitude, are shown as squares. Circles are parameters from the reanalysis. Filled symbols indicate significant slopes with latitude. Panels B and E show values and boxplots of the model coefficients for DOY ~ latitude, colored by response: positive (green), non-significant (gray), or negative (blue) correlations. Panels C and F are stacked barplots of the response signs representing the number of datasets demonstrating positive (green), non-significant (gray), or negative (blue) correlations with latitude. Panels B, C, E, and F show four sets of model results extracted from Fric et al. Supplemental Table 2, and one set of reanalysis results. For Fric et al. (2020) results, “SR” represents single regressions for DOY ~ latitude, while “RR” represents regression of residuals against latitude, corrected for altitude and year. “SR-105” and “RR-105” show results for all 105 datasets in the original analysis, while “SR-22” and “RR-22” only include results for the 22 species-region datasets used in our reanalysis. “New” shows results from our curation and reanalysis of those 22 species-region datasets. See Supplemental Figure 1 for a comparison of species-specific data and results.
Supplemental Figure 1 Caption:
These panels display the data and regression results for onset and termination across models. Each row of 3 panels represents a species in the re-analysis. In the left column, all raw occurrence data are shown as “+” while onset and termination are shown as ⧫; red points indicate individual observations used as both onset and termination. Fric et al.’s single regression results of DOY ~ latitude for onset and termination are overlaid on the data. In the middle column, the residuals used in the Fric et al. (2020) regression of residuals are shown for onset (▲) and termination (▼), respectively, with red indicating records of observations used as both onset and termination. Because each dataset comprises residuals, the “phenology shift” data are centered around 0 and the termination axis is shifted for easier interpretation. The slopes display the regression of residuals results from Fric et al. (2020) as reported in their supplementary tables. The right column shows the calculated onset (▲) and termination (▼) phenometrics calculated using the phest package in R. (Multiple observations for a latitudinal band represent different years), with the results from the multiple regression reanalysis. For all panels, the line format demonstrates positive (green, dashed), non-significant (black, dotted), or negative (blue, dashed) correlations with latitude in the corresponding models. While the Fric et al. analyses were generally reproducible, significance coding matches that reported in Fric et al. Supplemental Table 2, rather than our reproduction. We were unable to reproduce p values < 0.05 for the following single regression analyses: E. maturnaonset and L. virgaureae termination.