European plants with C4 photosynthesis: geographical and taxonomic distribution and relations to climate parameters

A survey of C-4 plants in Europe was performed with 216 species based on information in the literature and new studies. C-4 species were found in 10 families: the eudicots Amaranthaceae, Chenopodiaceae, Euphorbiaceae, Molluginaceae, Nyctaginaceae, Polygonaceae, Portulacaceae and Zygophyllaceae and the monocots Cyperaceae and Poaceae. The majority of the C-4 species belong to four families, Amaranthaceae (23), Chenopodiaceae (65), Cyperaceae (27) and Poaceae (88). In central and southern Europe, the abundance of native C-4 plants varied between 44 and 88% of total C-4 plants occurring, the rest being invasive C-4 species. The occurrence of total C-4 species, C-4 monocots and C-4 Chenopodiaceae was assessed for five major phyto-geographical regions of Europe (north-west, north-east, central, south-west, and south-east). The abundance of C-4 plants of total C-4 dicots, C-4 Chenopodiaceae, total C-4 monocots, C-4 Poaceae and C-4 Cyperaceae was related to the climatic variables of annual mean daily temperature, annual precipitation and DeMartonne's aridity index. The abundance of total C-4 plants decreases with increasing temperature and expression of aridity (decreasing aridity index) and is not correlated with precipitation. The abundance of total C-4 dicots and C-4 Chenopodiaceae is correlated with precipitation and aridity but not temperature, whereas the abundance of total C-4 monocots, C-4 Poaceae and C-4 Cyperaceae is correlated with temperature and aridity but not precipitation. (C) 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163, 283-304.