Table 3 Spearman rank correlation coefficients of all pairwise correlations between plant species diversity and biogeographical factors for the two Archipelagos

Total species richness (S)

Ion

0.928***

0.837***

-0.509*

ns

ns

-0.430*

0.772***

0.744***

Ae

0.850***

0.754***

0.422***

ns

ns

ns

0.724***

0.477***

Greek endemic species (GE)

Ion

0.865*

0.767*

ns

ns

ns

ns

0.819*

0.805*

0.902**

Ae

0.615*

0.564*

0.272*

0.181*

ns

-0.219

0.549*

0.481*

0.656*

Regional endemics (RE)

Ion

0.822*

0.786*

ns

0.736*

ns

ns

ns

ns

0.761*

Ae

0.685*

0.660*

0.299*

ns

ns

ns

0.676*

0.275*

0.708*

Single island endemics (SIE)

Ion

ns

ns

ns

ns

ns

ns

ns

ns

ns

Ae

0.699*

0.799*

ns

ns

ns

ns

ns

0.483

0.721***

Threatened species (TS)

Ion

0.830***

0.765***

-0.590*

ns

ns

-0.492*

0.827***

0.766***

0.878***

Ae

0.763***

0.749***

0.400***

ns

ns

ns

0.741***

0.513***

0.820***

Threatened Endemics (TES)

Ion

ns

ns

ns

ns

ns

ns

ns

ns

ns

Ae

0.663***

0.718***

0.253*

ns

ns

ns

0.645***

0.403***

0.687***