doi: 10.1111/njb.02156 00 1–12 NORDIC JOURNAL OF BOTANY Research 0 Determinants of alpha and beta vascular plant diversity in 61 Mediterranean island systems: the Ionian islands, Greece 65 5 Anna-Thalassini Valli, Konstantinos Kougioumoutzis, Eleni Iliadou, Maria Panitsa and Panayiotis Trigas 70 10 A.-T. Valli (http://orcid.org/0000-0002-2085-1174) (
[email protected]), K. Kougioumoutzis and P. Trigas (https://orcid.org/0000-0001-9557- 7723), Laboratory of Systematic Botany, Faculty of Crop Science, Agricultural Univ. of Athens, Athens, Greece. – E. Iliadou and M. Panitsa, Division of Plant Biology, Faculty of Biology, Univ. of Patras, Patras, Greece. 75 15 Nordic Journal of Botany The Ionian archipelago is the second largest Greek archipelago after the Aegean, but the factors driving plant species diversity in the Ionian islands are still barely known. 2018: e02156 80 20 doi: 10.1111/njb.02156 We used stepwise multiple regressions to investigate the factors affecting plant spe- cies diversity in 17 Ionian islands. Generalized dissimilarity modelling was applied Subject Editor: Rob Lewis to examine variation in the magnitude and rate of species turnover along environ- Editor-in-Chief: Torbjörn Tyler mental gradients, as well as to assess the relative importance of geographical and 85 25 Accepted 19 November 2018 climatic factors in explaining species turnover. The values of the residuals from the ISAR log10-transfomed models of native and endemic taxa were used as a measure of island floristic diversity. Area was confirmed to be the most powerful single explana- tory predictor of all diversity metrics. Mean annual precipitation and temperature, as 90 30 well as shortest distance to the nearest island are also significant predictors of vascular plant diversity.