Commonness and rarity in plants with special reference to the Sheffield flora part IV: A European context with particular reference to endemism

Abstract

With respect to reasons for commonness and rarity, an attempt is made to compare the flora of the Sheffield region with that of Europe as a whole. Land use appears to exert a critical effect on species abundance in both floras. However, European endemics, a grouping poorly represented in the Sheffield region and indeed in N Europe, form a very different class of rare species. Unlike the rare species of the Sheffield region, which are particularly associated with primitive families ( sensu Sporne, 1980), European endemics tend to be found in advanced families, the very families with the greatest proportion of common species. Thus, while the main factors controlling abundance in N Europe appear to be essentially similar to those operating in the Sheffield region, additional processes related to endemism must be taken into account in S Europe. Implications of these results for conservation policy are reviewed.