Giulio Ferretti

Plant invasions on small Mediterranean islands: An overview

Abstract Biological invasions have become one of the main drivers of habitat degradation and a leading cause of biodiversity loss in island ecosystems worldwide. The spread of invasive species poses a particular environmental threat on the islands of the Mediterranean Basin, which are hot spots of biodiversity and contain rare habitats and endemic species, especially on small islands, which are highly vulnerable to biodiversity loss. Following a recent survey, in this paper we aim to provide an overview of the present-day non-native vascular flora of small Mediterranean islands based on a sample of 37 islands located in the middle of the Mediterranean Sea, off the coast of Italy. By comparing the current data with those gathered during a previous survey conducted in the same study area, we also aim to highlight the main changes that have occurred in non-native plant species diversity, establishment and distribution in recent years and to present a first general overview of the most prominent plant taxa in the island’s introduced flora, focusing on those most responsible for these changes and those that pose the greatest environmental threats. We recorded 203 non-native plant species, 147 of which have established on at least one of the islands investigated. Overall, we detected a sharp increase in the number of species, in their levels of establishment and in the extent of their distribution within the study area in recent years. This may be explained by the intensification of research on plant invasions, as well as to new introduction, escape, establishment and invasion events on the islands in recent decades. The most remarkable plants detected include acacias and succulents, two groups that appear to be emerging very rapidly and to be posing new threats to the conservation of the islands’ natural environment, especially the genus Carpobrotus, whose spread into natural habitats containing rare and endemic taxa is seriously threatening biodiversity on both a local and global scale. On the whole, our results show that the plant invasion phenomenon in the study area has in recent years intensified considerably. As this process seems likely to continue, we should expect more establishment events in the future and the further spread of species that are already present. This is of particular conservation concern on the islands investigated in this survey, which are rich in endemisms, but have been facing deep socio-economic and environmental transformations in these last decades as a consequence of the abandonment of traditional management practices and the development of tourism. Our study thus confirms that plant invasions on Mediterranean islands are a serious environmental problem that threatens biodiversity conservation not only in the Mediterranean biogeographic region, but also on the global scale, and highlights the need to further increase efforts aimed at preventing, controlling or mitigating the effects of plant invasions in island ecosystems.

A checklist of the alien flora of the Tuscan Archipelago (Italy)

Biological invasions represent one of the major threats to biodiversity. Their impact is considered to be even higher in the island ecosystems, especially in Mediterranean ones, which host a very high diversity. Moreover nowadays the global changes and the local changes in the socio-economic drivers of these island enhanced human impact on the insular biota, also leading to an increase in alien species introductions and in a shift in the introduction pathways. In this framework, checklists of alien species represent a valuable tool for monitor the invasion process at a local scale. Aim of this paper is to provide an updated Checklist of the alien flora of the Tuscan Archipelago, also reporting some important information such year of first and more recent record and invasion status for each island. Intense field surveys were made to verify the presence of the reported species and detect the presence of new arrivals. The Checklist includes a total of 141 taxa belonging to 101 genera in 49 families. 31 taxa are considered invasive, 62 naturalized and 48 casual. Most of the species were introduced for ornamental purpose, according to socio-economical changes which nowadays see the tourism as the main economic driver in the Archipelago.

Mapping patterns of ferns species richness through the use of herbarium data

This paper aims to analyse the spatial patterns of sampling effort and species richness of pteridophyte in a well-investigated region as Tuscany, Italy, by using data stored from a geodatabase storing information on the specimens preserved in the main herbaria of the region. A total of 6,905 records about pteridophyte specimens were extracted from the geodatabase, and 5,638 of such specimens were studied through the use of spatial statistical techniques. The data about the sampling effort and species richness were analysed in relation to topographical variables to assess any significant relationship. Specimen-based rarefaction techniques were used to compare areas with different number of detected species. The analysis of the sampling effort data showed a nonhomogeneous distribution of herbarium data, with some areas being intensively sampled and others being almost unsampled. Thus, the geographical distribution of specimens was extremely clustered. The comparison across geographical areas through specimen-based rarefaction curves showed great differences in species richness and sampling completeness. The analysis of the residuals of species–area relationships evidenced that the distance to water bodies was the only significant topographical variable in controlling species diversity.

Detailed Natura 2000 and CORINE Biotopes habitat maps of the island of Elba (Tuscan Archipelago, Italy)

The island of Elba (Tuscan Archipelago, Italy) Natura 2000 habitat map (1:25,000) and the CORINE Biotopes habitat map (1:25,000) were derived from the phytosociological map of Elba integrated with recent studies and field knowledge of the vegetation units. Conventional geographical information system queries were used to manage and select the spatial information. For each map polygon, the following attributes were assigned: (i) habitat typology and (ii) percentage cover of each habitat type. Where multiple habitat types were associated with the same polygon, the percentage cover of each habitat type was estimated. A total of 27 Natura 2000 habitat types and 58 CORINE Biotopes habitat types were identified, these being distributed in single and/or multiple typological units. Distribution and covers of the different habitat types are discussed. The usefulness of this kind of map for monitoring and managing conservation actions is discussed.

Priority invasive alien plants in the Tuscan Archipelago (Italy): comparing the EPPO prioritization scheme with the Australian WRA

For the first time, we tested the European and Mediterranean Plant Protection Organization (EPPO) prioritization process (EPP) on 212 alien plant species thriving in the Tuscan Archipelago, Central Italy. We compared the results of the EPPO procedure with those of the Australian Weed Risk Assessment (A-WRA) system. The two methods were also tested against the categorization performed at the national and local level by a panel of experts. Our results suggest that both methods accurately predict the invasiveness of species already present in the Tuscan Archipelago. However, the total numbers of species included in the highest risk categories by the two methods differed greatly, with the EPPO prioritization process including fewer species in the highest risk class. The two methods differed in the ability to correctly detect the invasive species, with the A-WRA method being more conservative, but at cost of more species in the highest risk class. Using Generalized Linear Models, we showed that both methods suffer from some degree of dependence from one or more of the tested explanatory variables (life span, year of first record). The results suggest that the choice of a risk assessment method should be driven by the main aim of the assessment, i.e., distinguishing between a more predictive tool (A-WRA) and a prioritization tool (EPP) for already introduced species.

The Mediterranean salt steppes (order Limonietalia Br.-Bl. & O. Bolòs 1958) in Tuscany (Central Italy)

Abstract We conducted a phytosociological study of the halophile, chamaephytic, and hemicryptophytic communities found on coastal sand dunes and salt marshes in Tuscany, which mainly consist of Limonium spp. We describe the presence in Tuscany of communities referred to as Mediterranean salt steppes (Limonietalia), although we emphasize that they cover only small areas. We describe a new association, Limbardo crithmoidis-Limonietum etrusci, and a new alliance endemic to Tuscany, Limonion etrusci.

A phylogenetic study of two recently described endemic species of the Saxifraga granulata group from the central-north Mediterranean region (Italy) and their position in the context of the series Saxifraga (Saxifragaceae)

On two small islands of the Tuscan Archipelago, two new endemic species of the Saxifraga granulata group, namely S. caprariae and S. montis-christi, were recently described on a morphological basis. This led us to investigate these species using a molecular approach involving the analysis of ITS and trnL-F regions. Our aims were: to highlight their phylogenetic traits; to confirm or reject the hypothesis that they are more closely related to S. corsica than to S. granulata; and to verify their phylogenetic position in the context of Saxifraga L. ser. Saxifraga. We considered all the species belonging to the ser. Saxifraga and some other species of sect. Saxifraga – a total of 19 species. We generated 10 new DNA sequences, six for ITS and four for trnL-trnF. We produced separate Bayesian and Maximum likelihood trees for both ITS and trnL-trnF regions and we analysed the genetic distances among the new endemics and the more closely related species. The phylogenetic analyses showed that S. caprariae and S. montis-christi are relatively well separated from S. granulata and more related to S. corsica. This supports the taxonomic treatment previously proposed. We showed that the results of our phylogenetic analysis are in agreement with our biogeographic knowledge of the Tuscan Archipelago and the neighbouring territories and emphasize the conservation relevance of these findings.

Natura 2000 habitat of Mt. Argentario promontory (southern Tuscany, Italy)

ABSTRACT The Mt. Argentario promontory (southern Tuscany, Italy) is a protected area hosting habitats and species of European importance. The Mt. Argentario Natura 2000 habitat map (1:10,000) was compiled from photo-interpretation and field surveys, integrated with data from past cartographic and phytosociological studies. Conventional geographical information system procedures were used to select and manage spatial information, and delimit the map polygons. The following attributes were assigned to each map polygon: (i) habitat type name, with Natura 2000 code and (ii) percentage cover of the habitat type. Where multiple habitat types were associated in a mosaic attributed to the same polygon, the percentage cover of each habitat type was estimated. The survey allowed to identify and map a total of 13 Natura 2000 habitat types covering more than 40% of the study area. Presence and conservation importance of the detected habitat types are discussed, together with the usefulness of this kind of maps for monitoring and managing purposes.

Contributi per una flora vascolare di Toscana.VIII (440-506).

Jsou předkladany nove lokality a/nebo potvrzeni týkajici se 67 rostlinných taxonů toskanske flory cevnatých rostlin, ktere patři k 59 rodům a 37 celedim.