Non‐native flora of Italy: Species distribution and threats

Abstract

In this paper, we provide an overview of the distribution and invasive status of non‐native species in the Italian flora across its administrative regions, biogeographic regions and main land use types, and a synthesis of current knowledge on the threats they pose within the country. The information on non‐native plant species collected during the project “A survey of the non‐native Italian flora” was used to compile comprehensive regional and national databases. The number of non‐native species within a given administrative region increases in proportion to its size, resident population density and latitude, reaching the highest values in the intensively cultivated, heavily industrialized and urbanized Po Plain in northern Italy. The number of casual species is positively correlated with the number of yearly visitors in each region and negatively correlated with the proportion of mountainous terrain within the region. If compared with the Continental and Mediterranean biogeographic regions, the Alpine region yields the lowest number of non‐native species and lowest proportion of casual species. The number and density of introduced species is highest in artificial land use types, particularly in urban areas. A negative impact is reported to be exerted by 203 species, most of which are agricultural weeds.

Keywords:

• Alien flora
• biogeographic pattern
• impacts
• Italy
• land use types
• plant invasions

Acknowledgements

Although we have only cited one author per region, we wish to express our gratitude to all those people who helped gather, from the great variety of sources available, the data upon which this project is based. In particular, this work would never have been completed without the help of the following experts who lead regional groups: Liliana Bernardo (Calabria), Vincenzo La Valva (Campania), Pietro Mazzola (Sicily), Silvano Marchiori (Puglia), Consolata Siniscalco (Piedmont) and Noemi Tornadore (Veneto).

We would also like to thank the following local collaborators for their contribution to the regional teams: Rita Accogli, Antonella Albano, Giuseppina Barberis, Alessio Bertolli, Giacomo Bracchi, Guido Brusa, Mario Calbi, Luisa Carta, Rosanna De Mattei, Alessandra Di Turi, Giulio Ferretti, Francesco Festi, Carmen Gangale, Luca Gariboldi, Gruppo Botanico Milanese, Gruppo Flora Alpina Bergamasca, Flavia Landucci, Manuela Manca, Aurelio Manzi, Francesca Marinangeli, Concetta Mele, Maria Francesca Palla, Mauro Pellizzari, Aldo Ranfa, Arcangelo Schiappacasse, Adriano Soldano, Gianni Tognon and Dimiter Uzunov.

We wish to thank Mauro Ballero (aerobiology), Mauro Bassignana (agronomy), Maria Lucia Leporatti (toxicity), Mauro Serafini (toxicity, EFSA, European Food Safety Authority), Francesco Vidotto (agronomy) and Pasquale Viggiani (agronomy) for providing publications, unpublished records and information on the impact of the invasive plants.

We are very grateful to Giovanna Abbate, Lewis Baker, Sandro Bonacquisti, Barbara Dalla Bona, Piera di Marzio, Enzo Dominici, Aldo Marchetto, Francesca Pauselli and Francesca Pavesi for their contribution to various aspects of the project. We also wish to thank Petr Pyšek and Ingo Kowarik for their helpful advice and precious comments throughout the project.

This study is a part of “A survey of the non‐native flora of Italy”, a research project developed in the years 2005–08, funded by the Italian Ministry for the Environment, Land and Sea Protection, directed by Professor Carlo Blasi, coordinated by Laura Celesti‐Grapow, Giuseppe Brundu, Ignazio Camarda, Lucia Viegi and Carlo Blasi, and by the Inter‐university Biodiversity, Plant Sociology and Landscape Ecology Research Centre (CIRBFEP – Centro di Ricerca Interuniversitario Biodiversità, Fitosociologia ed Ecologia del Paesaggio) of the Sapienza University of Rome.