Marisa Vidali

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.

Riparian Salix alba: Scrubs of the Po lowland (N-Italy) from an European perspective

Abstract This paper deals with riverine Salix alba – scrubs of the Po plain (northern Italy). They were compared with analogous formations of many other European countries to study similarities and differences. Demographic concentration and intense human activities (agriculture, industry) in the basin of the Po River are among the highest in Europe, with the remarkable consequence that all hygrophilous woods and bushes contain a high number of alien species. The units dominated by Salix alba were analyzed. Their originality in comparison with the similar associations of Mediterranean, central- and SE-Europe was emphasized.

Correlations among biodiversity, biomass and other plant community parameters using the phytosociological approach: A case study from the south-eastern Alps

Abstract The present study deals with the grassland complex of communities which may be found on the limestones in the south-eastern Alps; these communities show in fact a particular interest for their high biodiversity degree and for their importance for the traditional land-use economy of the south-European mountain regions. Phytosociological relevés corresponding to well-defined plant associations have been used in order to get information on the relationships among plant species diversity, biomass, chorotypes, pollination types, functional strategies and soil characteristics. The analysis was carried out both along an altitudinal and a soil evolution gradient. The analysis of the correlations among the variables and the application of the principal component analysis shows a positive correlation between soil parameters and biomass, eurichory, anemogamy and C- and R-strategies; on the contrary, a negative correlation among stenochory, entomogamy and S-strategy with the soil evolution seems to be present. This article shows how the phytosociological approach can be used to get information and knowledge on the correlations between several variables useful to understand the complex nature of the plant communities in order to support management plans.

A diachronic approach to assess alien plant invasion: the case study of Friuli Venezia Giulia (NE Italy).

Abstract Direct experimental methods for measuring plant invasiveness based on generative vs. vegetative reproductive mechanisms have already been proposed in the literature. In the present work, an indirect method to measure plant species invasion using historical and current data from various sources is described. This method involves a diachronic approach whereby the speed of plant invasion can be measured as the rate of new site colonisation by species over time. The study was conducted in Friuli Venezia Giulia (NE Italy). Field data, herbarium collections and data from the literature since the late 19th century were used to gather information on the presence or absence of some alien species through time, and a simple index to measure the invasion rate in the territory was developed. Results show that the diachronic approach allowed the identification of species that are generally recognised as more invasive already in other studies.

Floristic Databanks and the Phytogeographic Analysis of a Territory

In recent years there have been rapid developments in the field of floristic databanks (Brenan et al. 1975; Allkin and Bisby 1984). Such banks allow a quick and efficient retrieval of a great number of phytogeographic data otherwise scattered in the literature or in herbaria. They can produce computerized distribution maps, or complex matrices of floristic, ecological and geographic data. The distribution maps may be processed by classification programs, to obtain groups of species with similar distribution (chorological types, geoelements); the matrices may be analyzed by multivariate methods to reveal and causally explain trends of phytogeographic variation.

Inclusion of phytosociological data in an index of vegetation fire danger: application and mapping on the Karst area around Trieste (Italy)

Abstract In this paper we propose a method to produce maps of fire danger index (FDI). The index includes in the formula a vegetation pyrogenic potential index (VPPI) based on floristic phytosociological data. The map of FDI is produced by integrating available phytosociological maps of vegetation, geomorphology and climate, using the Geographic Information System technology. The method is applied to an area of the coastal Classical Karst (NE-Italy). While fire risk maps based on the incidence of previous fires are useful for facilitating emergency operations, e.g. the allocation of fire fighting resources, we conclude that the proposed index offers an effective tool to plan actions for fire prevention.