Temporal niche separation of the alien flora of Rome (Italy).

This paper deals with the flowering patterns of alien and native species of the urban flora of Rome. Our hypothesis is that beside their confinement in space, i.e. to very disturbed habitats, several aliens also show a segregation in time, by flowering during and/or after the summer vegetative or blossoming break of most local species. Data from the database of the flora of Italy, from a phenology survey in the city centre and from a field survey of the late-flowering flora of the whole city are presented. The results suggest that the role played by alien species in the flora of the city has a consistent seasonal variation, being more significant in summer and autumn than in spring. A possible explanation for this trend may be that some alien species occupy available temporal-niches unexploited by native species, thus avoiding competition with local Mediterranean plants.

[1]  J. Brock,et al.  The importance of alien and native species in the urban flora of Rome (Italy) , 2001 .

[2]  C. Ricotta,et al.  Topological analysis of the spatial distribution of plant species richness across the city of Rome (Italy) with the echelon approach , 2001 .

[3]  C. J. West,et al.  Naturalization and invasion of alien plants: concepts and definitions , 2000 .

[4]  C. Blasi,et al.  A COMPARISON OF THE URBAN FLORA OF DIFFERENT PHYTOCLIMATIC REGIONS IN ITALY , 1998 .

[5]  Petr Pyšek,et al.  Is there a taxonomic pattern to plant invasions , 1998 .

[6]  H. Dietz,et al.  Phenological shifts of the alien colonizer Bunias orientalis: Image‐based analysis of temporal niche separation , 1997 .

[7]  George E. Policello,et al.  Robust Rank Procedures for the Behrens-Fisher Problem , 1981 .

[8]  J. Brock,et al.  Investigations on some reproductive features of invasive alien plants in Italy. , 2001 .

[9]  P. Pyšek.  Alien and native species in Central European urban floras: a quantitative comparison , 1998 .

[10]  H. Sukopp,et al.  Urban Ecology — Scientific and Practical Aspects , 1998 .

[11]  G. Salvatore.  La Flora Esotica Nelle Colture Agrarie , 1994 .

[12]  K. Sykora.  History of the impact of man on the distribution of plant species , 1990 .

[13]  F. Castri.  On invading species and invaded ecosystems: the interplay of historical chance and biological necessity , 1990 .

[14]  H. Sukopp,et al.  Extinction and Naturalization of Plant Species as Related to Ecosystem Structure and Function , 1987 .

[15]  F. Bazzaz.  Life History of Colonizing Plants: Some Demographic, Genetic, and Physiological Features , 1986 .

[16]  E. Pacini,et al.  Reproduction in Mediterranean plants , 1984 .

[17]  H. Sukopp,et al.  Urban environments and vegetation , 1983 .

[18]  С. Raunkiaer.  Types biologiques pour la geographie botanique , 1905 .