Floristic elements in European vascular plants: an analysis based onAtlas Florae Europaeae

Abstract

Aim To identify floristic elements in the European flora by an analysis of the distributions of species and species groups mapped in Atlas Florae Europaeae. Location Europe, as defined by Flora Europaea. Methods We analysed the native distributions of 2762 species and 33 species’ aggregates from 79 families, which represent c. 20% of the European flora. The distributional data base, derived from Atlas Florae Europaeae, includes records from 4420 50 × 50‐km UTM grid squares. We classified species into floristic elements by a three‐stage clustering procedure, which consisted of: (1) constructing a dissimilarity hierarchy by complete linkage clustering, using a distance measure based on Jaccard’s coefficient; (2) cutting the hierarchical tree at the 0.95 level to create initial clusters, and forcing small clusters to link with larger ones until the sum of within‐group pairwise distances exceeded a threshold value; and (3) checking the allocation of all species to the redefined clusters and reassigning species if appropriate, using the cosine of the angle between the species and cluster centres to measure the similarity of species to clusters. Results The clustering procedure classified 2793 taxa into 18 floristic elements, which included between 66 and 289 taxa; two species had unique, non‐overlapping distributions and could not be classified. Main conclusions The analysis highlights the floristic diversity of the mountains of central and southern Europe, and of the Mediterranean region. The floristic elements of northern latitudes and the temperate lowlands tend to be composed of wide‐ranging species and include only a low proportion of European endemics. The montane elements, including those centred on montane areas in the Mediterranean region, are composed predominantly of perennial species and include high or very high proportions of European endemics. Classifications that recognize one ‘Alpine’ and one ‘Mediterranean’ biogeographical zone in Europe fail to reflect this floristic diversity.

Plant species radiations: where, when, why?

“…We would also expect a certain time lag, and predict that the newly deglaciated habitats of the Northern Hemisphere, although being new habitats, should still do not have a rich endemic flora. Curiously, the highest endemism in Europe is in the previously glaciated alpine arc (Finnie et al 2007), and genera such as Carex and Astragalus are very species rich. It would be nice to know whether 10 ka, 100 ka or 1 Ma are needed for diversification to become evident at species level.…”

Biogeographical patterns in the British and Irish flora

“…We have recently been attempting to develop methods to identify floristic elements by the detection of recurrent patterns in the distribution maps produced by atlas projects. We started with a study of European vascular plants, and then analysed British and Irish mosses and liverworts (Finnie et al 2007;Preston et al 2011Preston et al , 2013. The bryophyte studies have thrown light on the ecological factors controlling the distribution of mosses and liverworts at the 10-km square scale, and have revealed significant differences in the reproductive strategies, conservation statuses and wider ranges of the species comprising different biogeographical elements.…”

Analysis of the Transdanubian region of Hungary according to plant species diversity and floristic geoelement categories

“…The attempts to determine floristic element categories (Finnie et al, 2007) were based on the distribution maps of Atlas florae Europaeae Suominen, 1972-1994;Jalas et al, 1996Jalas et al, , 1999. This Atlas only covers 20% of European flora; therefore, we could not use it for the Hungarian taxa.…”