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An updated inventory of the vascular flora alien to Italy, providing details on the occurrence at regional level, is presented. The checklist includes 1597 species, subspecies, and hybrids, distributed in 725 genera and 152 families; 2 taxa are lycophytes, 11 ferns and fern allies, 33 gymnosperms, and 1551 angiosperms. 157 taxa are archaeophytes and 1440 neophytes. The alien taxa currently established in Italy are 791 (570 naturalized and 221 invasive), while 705 taxa are casual aliens, 4 are not assessed, 7 are of unknown regional distribution, 47 have not been confirmed in recent times, 3 are considered extinct or possibly extinct in the country, and 40 are doubtfully occurring in Italy. This checklist allows to establish an up-to-date number (9792) of taxa constituting the whole (native and alien) Italian flora. [ABSTRACT FROM AUTHOR]

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 genusCarpobrotus, 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. [ABSTRACT FROM PUBLISHER]

Prevention and early detection are considered to be the most effective means of managing non-native invasive species that have serious ecological and economic impacts. Consequently, the study of those taxa that are still in an early stage of invasion but are highly likely to spread and to have a significant adverse impact in future is becoming an increasingly important issue in both the research on and management of invasive species. In Italy, one such species isArctotheca calendula(L.) Levyns, a herbaceous plant of theAsteraceaefamily that is native to South Africa. Here, we present an overview of current knowledge on the distribution and potential impacts of this species in Italy, and we outline some features that are crucial to understanding and preventing its invasive spread. [ABSTRACT FROM PUBLISHER]

The aim of this paper is to document plant diversity in the metropolitan area of Rome (Italy) by providing a comprehensive inventory of the present-day vascular flora and an overview of its composition and species diversity. We compiled the floristic catalogue by including all vascular plant entities that occur spontaneously within the administrative boundaries of the Rome municipality. The data, which were gathered from extensive field surveys, from a broad review of the literature and from herbaria records, were updated and integrated in a comprehensive account. The inventory of the flora of metropolitan Rome lists 1649 entities, from 139 families and 677 genera. The flora contains 228 taxa that are non-native to the Italian flora, 81 of which are established in the study area. The overview of flora reveals a remarkable species diversity and outlines the main characteristics of the flora of Rome, which may be summarized as (1) a large number of taxa of high conservation value which occur in remnants of near-natural vegetation, (2) the loss or decline of some species, particularly of native freshwater plants, (3) a remarkably high native species richness within the urban area, which includes many native woody species and (4) a rich ruderal flora, prevalently composed of native species that are well adapted to human disturbance, along with a variety of taxa of non-native or uncertain origin. The large set of data and the overview presented in this paper represent a fundamental framework for future research and for the conservation of plant diversity in metropolitan Rome. [ABSTRACT FROM PUBLISHER]

This article provides general information and original data on the period of first introduction in Europe (1823–1825) and in Italy (first half of the 19th century), and on the current distribution and impacts in Italy of the invasive macrophyteEichhornia crassipes. Two main pathways are responsible for the presence of this species in Italy: (i) introduction as an ornamental and (ii) research and use for phytoremediation. After a time lag of more than 100 years,E. crassipeshas recently started invading the Italian freshwaters. A specific action plan for this species is required, including local eradication and awareness campaigns. Furthermore, regulations in the trade sector of invasive aquatic plant species need to be introduced and the possibilities for biological or integrated control evaluated. [ABSTRACT FROM PUBLISHER]

This work provides an overview of plant diversity in the municipality of Rome (Italy) through an assessment of the flora in urban and suburban sectors of the city. It is aimed at providing the knowledge required to support proactive action for plant conservation. On the basis of a literature-derived catalogue and of an extensive survey campaign, the flora was investigated in terms of conservation interest; habitat types and locations that require protection measures were identified according to the occurrence of valuable native plants. Valuable species exclusive of the urban sector are threatened by the compaction trend affecting the urban fabric. Such species occur mainly in ruderal environments and fallows of archaeological sites and urban parks, near river courses and in remnants of natural forests. Valuable species exclusive of the suburban sector are threatened by urban sprawl. They occur prevalently in wet environments of the subcoastal strip and in coastal sands, Mediterranean maquis, tuffaceous gorges, sulphur springs and archaeological sites. The results highlight the need to preserve the complexity of the land mosaic, especially within the urban matrix, and to strengthen the existing environmental protection tools in the suburban area against foreseeable land cover changes. [ABSTRACT FROM AUTHOR]

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The main aim of this paper is to assess the drivers of non-native plant species richness and composition on a set of 37 small Mediterranean islands in Italy. We compiled the list of the non-native flora and distinguished species according to their establishment status. The non-native flora of the islands studied consists of 154 species, 105 of which are established on at least one island. Regression tree analysis revealed that the main determinants of both total non-native and established non-native species richness are the variables linked to tourist development and the sprawl of artificial surfaces. The variation partitioning approach shows that the variation in total non-native flora composition is driven above all by environmental variables, whereas when established taxa are considered, human-mediated factors account for most of the explained variation. Mediterranean islands have recently experienced changes in the type and intensity of human activities, leading to a decline in rural landscape and the development of tourist facilities. Our results indicate that tourism and the increase in the extension of artificial surfaces are also the main drivers of non-native plant species occurrence and establishment. These factors outweigh the effects of abiotic variables such as climate and lithology in determining the number of non-native species, whether it be total or established, as well as variations in the composition of established species. High human pressure and ornamental introductions associated with tourist activities appear to be the key elements that need to be considered when planning strategies aimed at managing plant invasions in Mediterranean islands. [ABSTRACT FROM AUTHOR]

Biological invasions are regarded as one of the main drivers of habitat degradation in island ecosystems. Mediterranean islands have been subjected to a high degree of land conversion over the past 60 years, resulting in a massive reduction in the amount of rural land and the sprawl of tourist activities. The aims of this paper are to evaluate the current level of invasion of alien plant species in semi-natural vegetation types that have developed after the abandonment of agriculture and to analyze the relationships between non-native species, native flora, and environmental characteristics. Two Italian islands (Ponza and Ventotene) were surveyed using a random-stratified sampling. The occurrence and relative cover of alien plant species were compared and separate analyses were performed for the native flora. Abundance patterns of both native and alien species were then studied in the light of the environmental and anthropogenic features. Although we found that some non-native species are extremely widespread, their relative cover at the plot level is low. Permutational Multivariate Analysis of Variance and Indicator Species Analysis revealed dissimilarities in the native species composition, while Mann–Whitney and Kruskal–Wallis tests showed differences in the ecological requirements (moisture, soil reaction, and nitrogen) of the native species pool. Canonical Correspondence Analysis pointed to the importance of the proximity to agricultural areas, human disturbance, and past land management, particularly residual terraces, in determining the difference between plant communities on the two islands. The results of our study suggest that traditional forms of agriculture may represent a key element for countering the establishment and spread of non-native plants in Mediterranean areas. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper we present a comprehensive inventory of the non-native vascular flora of Italy, which was produced within the project “A survey of the Italian non-native flora”, funded by the Italian Ministry for the Environment. Previously published floristic accounts were the main source of information. Historical records were critically revised and integrated with recent literature, data from herbaria and some unpublished information, so as to obtain a complete, up-to-date catalogue of the non-native vascular plant species that occur spontaneously in Italy. The inventory lists 1023 non-native species and subspecies, which account for 13.4% of all the Italian flora. The Italian non-native flora was divided, according to its residence time, into 103 archaeophytes and 920 neophytes. According to its current invasion status, it was classified into 437 casual (42.7% of all non-native) and 524 established taxa, the latter being divided into 361 naturalized non-invasive (35.3%) and 163 invasive taxa (15.9%). The inventory includes a group of 62 species (6.1%) that lack recent records (i.e. since 1950). By combining local expertise into a unified, nationwide scheme using a standardized method and terminology, the inventory provides the essential scientific basis for the development of plant invasion research and management in the country. [ABSTRACT FROM AUTHOR]