Appendix S2. Pearson's Correlations Between Variables

Appendix S2. Pearson's correlations between variables

We calculated the Pearson's correlations among diversity components (Table S2.1), among abiotic factors (Table S2.2), and among abiotic factors and diversity components (Table S2.3)of 23 oceanic archipelagos worldwide.

Table S2.1.Pearson's correlations among diversity components of vascular plants on 23 oceanic archipelagos worldwide.Diversity components were measured in species numbers (i.e. species richness). Significant correlations are shown in bold. Correlations were calculated for log10-transformed variables, except for the ratios.βrpl = βA replacement; βnst = βA nestedness. P values: ** 0.01>P>0.001; ***P<0.001.

α / βA / βrpl / βnst / βA/α / βrpl/βnst
βA / 0.83***
βrpl / 0.81*** / 0.98***
βnst / 0.77*** / 0.96*** / 0.88***
βA/α / 0.20 / 0.65*** / 0.61** / 0.68***
βrpl/βnst / 0.09 / 0.10 / −0.11 / 0.33 / 0.10
γ / 0.93*** / 0.97*** / 0.95*** / 0.92*** / 0.54** / 0.10

Table S2.2.Pearson's correlations among abiotic factors. Significant correlations are given in bold, with the respective P values in the upper part of the table. Variables’ calculations and sources can be found in the main text and in appendix S1.Al= island area; Am= mean island area; Dc= distance to nearest continent; O = surrounding landmass proportion; M = age of the oldest island; Em= mean elevation; Ea= maximum elevation; T0 = annual mean temperature; P0 = annual mean precipitation; Ts= annual temperature range; Ps= coefficient of variation of precipitation; Vt= Late Quaternary (LQ) climate change velocity of temperature; Vp= LQclimate change velocity of precipitation; N=number of islands; Ar= range of island area; Di= mean inter-island distance; Hc = climatic environmental volume; Hg= geographic environmental volume; Ht= environmental volume; C = connectivity; Ah = archipelagohull; Ap = proportion of land area.P values: * 0.05>P>0.01; ** 0.01>P>0.001; ***P<0.001.

Al / Am / Dc / O / M / Em / Ea / T0 / P0 / Ts / Ps / Vt / Vp / N / Ar / Di / Hc / Hg / Ht / C / Ah / Ap
Al / 1 / *** / ** / *** / * / ** / * / *** / *** / *** / *** / *** / ** / ** / *
Am / 0.92 / 1 / * / * / *** / *** / * / ** / *** / *** / ** / ** / ** / *** / ***
Dc / −0.35 / −0.45 / 1 / *** / * / ** / ** / * / ** / **
O / 0.32 / 0.46 / −0.86 / 1 / ** / ** / * / ** / **
M / 0.13 / 0.03 / −0.42 / 0.25 / 1 / *
Em / 0.59 / 0.67 / −0.15 / 0.11 / −0.20 / 1 / *** / * / * / *** / * / * / *** / ***
Ea / 0.65 / 0.66 / −0.10 / 0.07 / −0.20 / 0.96 / 1 / * / *** / ** / ** / **
T0 / −0.11 / −0.24 / 0.30 / −0.21 / 0.08 / −0.46 / −0.36 / 1 / ** / * / * / *
P0 / −0.06 / −0.15 / 0.62 / −0.6 / −0.01 / 0.13 / 0.16 / −0.24 / 1 / ***
Ts / 0.42 / 0.50 / −0.62 / 0.53 / −0.07 / 0.43 / 0.44 / −0.57 / −0.36 / 1
Ps / 0.24 / 0.21 / −0.46 / 0.49 / 0.17 / −0.08 / −0.04 / 0.47 / −0.7 / 0.12 / 1
Vt / −0.62 / −0.61 / −0.18 / 0.21 / 0.29 / −0.69 / −0.73 / −0.15 / −0.15 / −0.11 / −0.12 / 1 / ** / *
Vp / −0.48 / −0.65 / 0.35 / −0.33 / 0.08 / −0.43 / −0.40 / 0.12 / 0.39 / −0.35 / −0.25 / 0.36 / 1 / * / *
N / 0.66 / 0.32 / 0.01 / −0.13 / 0.27 / 0.14 / 0.30 / 0.20 / 0.14 / 0.06 / 0.18 / −0.32 / 0.08 / 1 / ** / ** / *** / *** / *** / ***
Ar / 0.93 / 0.86 / −0.28 / 0.30 / 0.13 / 0.51 / 0.61 / −0.05 / 0.00 / 0.37 / 0.15 / −0.56 / −0.40 / 0.62 / 1 / *** / *** / *** / * / * / *
Di / 0.29 / 0.10 / 0.15 / −0.31 / 0.11 / −0.07 / 0.02 / 0.29 / 0.01 / 0.14 / 0.15 / −0.33 / 0.03 / 0.54 / 0.19 / 1 / ** / * / ** / *** / **
Hc / 0.77 / 0.55 / −0.08 / 0.01 / 0.12 / 0.18 / 0.34 / 0.30 / −0.09 / 0.17 / 0.35 / −0.48 / −0.27 / 0.82 / 0.73 / 0.57 / 1 / *** / *** / ***
Hg / 0.72 / 0.53 / −0.33 / 0.29 / 0.45 / 0.10 / 0.22 / 0.20 / −0.20 / 0.17 / 0.34 / −0.2 / −0.18 / 0.73 / 0.74 / 0.37 / 0.82 / 1 / *** / ***
Ht / 0.78 / 0.57 / −0.24 / 0.18 / 0.28 / 0.20 / 0.35 / 0.20 / −0.13 / 0.21 / 0.33 / −0.36 / −0.23 / 0.81 / 0.78 / 0.46 / 0.95 / 0.93 / 1 / ***
C / 0.54 / 0.72 / −0.55 / 0.57 / 0.02 / 0.64 / 0.54 / −0.47 / −0.09 / 0.39 / 0.09 / −0.27 / −0.49 / −0.07 / 0.50 / −0.50 / 0.00 / 0.11 / 0.10 / 1 / ***
Ah / 0.54 / 0.28 / 0.15 / −0.23 / 0.12 / −0.01 / 0.14 / 0.37 / 0.02 / 0.05 / 0.19 / −0.39 / −0.04 / 0.80 / 0.48 / 0.86 / 0.84 / 0.67 / 0.75 / −0.40 / 1 / *
Ap / 0.52 / 0.70 / −0.53 / 0.57 / 0.02 / 0.64 / 0.55 / −0.49 / −0.08 / 0.40 / 0.06 / −0.26 / −0.48 / −0.11 / 0.51 / −0.60 / −0.03 / 0.09 / 0.07 / 0.99 / −0.44 / 1

Table S2.3.Pearson's correlations among abiotic factors and diversity components.Diversity was measured in species numbers. Significant correlations are in bold. All variables were log-transformed, except for the diversity ratios (βA/α and βrpl/βnst), mean temperature, mean precipitation, absolute latitude and age. Discarded variables are shown in italic font.βrpl = β replacement; βnst = β nestedness. P values: .0.1P>0.05; * 0.05>P>0.01; ** 0.01>P>0.001; ***P<0.001.

Type of variable / Variable / α / βA / βA/α / βrpl / βnst / βrpl/βnst / γ
Biogeographic / Island area (m2) / 0.62** / 0.65*** / 0.5* / 0.62** / 0.71*** / 0.11 / 0.7***
Mean island area (m2) / 0.63** / 0.49* / 0.22 / 0.46* / 0.53** / 0.10 / 0.6 **
Distance to nearest continent (m) / −0.57** / −0.36. / −0.09 / −0.35. / −0.33 / −0.04 / −0.47*
Surrounding landmass proportion (unitless) / 0.66*** / 0.33 / −0.16 / 0.35 / 0.26 / −0.09 / 0.47*
Age of oldest island (million years) / 0.29 / 0.32 / 0.38 . / 0.34 / 0.28 / −0.08 / 0.36 .
Mean elevation (m) / 0.28 / 0.23 / 0.17 / 0.19 / 0.29 / 0.20 / 0.29
Maximum elevation m / 0.33 / 0.38. / 0.32 / 0.34 / 0.43* / 0.16 / 0.40.
Climatic / Annual mean temperature (˚C) / 0.20 / 0.29 / −0.04 / 0.32 / 0.22 / −0.12 / 0.22
Annual mean precipitation (mm year−1) / −0.42* / −0.24 / 0.24 / −0.24 / −0.18 / −0.06 / −0.28
Annual range in temperature (˚C) / 0.42* / 0.36. / 0.26 / 0.30 / 0.39 . / 0.30 / 0.42*
Coefficient of variation of precipitation (unitless) / 0.56** / 0.53** / 0.05 / 0.51* / 0.46* / 0.13 / 0.52*
Late Quaternary (LQ) climate change velocity of temperature(m year−1) / −0.36 . / −0.44* / −0.29 / −0.39. / −0.49* / −0.25 / −0.44*
LQ climate change velocity of precipitation (m year−1) / −0.24 / −0.02 / 0.17 / 0.025 / −0.06 / −0.17 / −0.11
Intra−archipelagic / Number of islands / 0.29 / 0.65*** / 0.79*** / 0.62** / 0.72*** / 0.07 / 0.55**
Range in island area (m2) / 0.60** / 0.65*** / 0.50* / 0.67*** / 0.64** / −0.18 / 0.69***
Mean inter−island distance (m) / 0.06 / 0.42* / 0.59** / 0.31 / 0.51* / 0.43* / 0.29
Climatic environmental volume(unitless) / 0.42* / 0.68*** / 0.62** / 0.66*** / 0.71*** / 0.02 / 0.61**
Geographic environmental volume (unitless) / 0.54** / 0.72*** / 0.57** / 0.74*** / 0.67*** / −0.21 / 0.68***
Environmental volume (unitless) / 0.51* / 0.74*** / 0.65*** / 0.74*** / 0.73*** / −0.12 / 0.68***
Connectivity (unitless) / 0.47* / 0.14 / −0.12 / 0.15 / 0.15 / −0.03 / 0.31
Archipelago hull (m2) / 0.19 / 0.55** / 0.64** / 0.49* / 0.62** / 0.18 / 0.43*
Proportion of land area (unitless) / 0.46* / 0.14 / −0.11 / 0.16 / 0.13 / −0.07 / 0.31