Alien plant species distribution in the European Alps: influence of species’ climatic requirements

Biological Invasions

Matteo Dainese*, Ingolf Kühn, Luca Bragazza

* Department of Land, Environment, Agriculture and Forestry, University of Padova, Viale dell’Università 16, I-35020 Legnaro (PD), Italy

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Appendix 1 Alien plant species richness distribution in the 55 administrative divisions for: (a) northern Holarctic alien plants, (b) Mediterranean alien plants, (c) tropical-subtropical alien plants, (d) subalpine alien plants, (e) montane alien plants, (f) colline alien plants, (g) warm colline alien plants, and (h) very warm colline alien plants.

Appendix 2

Table 1 Pearson correlations between environmental variables

AREA / TEMP / PREC / HUM / ART / FOR
TEMP / -0.410 / **
PREC / -0.022 / ns / -0.536 / ***
HUM / 0.299 / * / 0.223 / ns / -0.323 / *
ART / -0.243 / ns / 0.399 / ** / -0.258 / ns / 0.499 / ***
FOR / 0.272 / * / 0.105 / ns / -0.497 / *** / 0.296 / * / -0.022 / ns
ELE-R / 0.626 / *** / -0.595 / *** / 0.485 / *** / -0.035 / ns / -0.466 / *** / -0.032 / ns

Significant correlations are indicated by * (P < 0.05), ** (P < 0.01), *** (P 0.001); ns, no significant

correlation

Fig. 1 Scatterplots of elevation range versus: (a) minimum temperature of the coldest month, (b) precipitation of the driest month (%), (c) area cover by urban elements, and (d) area covered by forests. Curves were generated by a generalized additive model (GAM) smoother (df = 2).

Appendix 3 Different frequency histograms of the area of administrative divisions across twelve temperature bands (i.e., minimum temperature of the coldest month). The administrative divisions were grouped into five surface intervals: (a) 0-500 km2, (b) 500-1500 km2, (c) 1500-3500 km2, (d) 3500-7500 km2, and (e) greater than 7500 km2. The temperature bands were grouped into 2°C intervals. Arrows indicate the mean temperature value for each class of the administrative divisions.