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An updated and annotated catalogue of the vascular plants reported for the Arezzo administrative province (eastern Tuscany, Italy) is presented. The study tries to fill the gaps existing in the data at the sub-regional administrative scale, addressing relevant taxonomic and distribution issues, important not only at local level. The catalogue was compiled by gathering all the botanical information from various source types (old and recent floras, vegetation data, taxonomic studies, floristic and chromosome number reports, herbarium data, landscape studies, original field observations). More than 32,000 records were critically examined, georeferenced and stored in a floristic database. For many controversial taxa, considerations and case-by-case comments are reported in explanatory notes. A distribution map of report locations and a map of floristic information intensity (number of records per location) are provided. The total number of taxa registered is 2082, of which four Lycophytes, 42 Ferns and fern allies, 47 Gymnosperms and 1989 Angiosperms. In the total list, 1759 taxa were confirmed after 1950, 126 recorded before 1950, 116 considered inquirendae and 81 excludendae. Amongst the taxa confirmed after 1950, 1518 are native, 13 cryptogenic and 228 alien, of which 104 considered cultivated and 29 invasive for the Arezzo province. Data were analysed in relation to number of families, consistence of native and alien flora, chorological and general conservation aspects. [ABSTRACT FROM AUTHOR]

Mediterranean ecosystems have a high diversity of plants, especially in mountain areas; this diversity is especially high in the eastern sector of the Spanish Central Range, where Mediterranean and Eurosiberian species contact. Parts of these plants have been favoured by human activities throughout the last millennia, in an intentional or unintentional way. We have studied the composition of the flora of a valley in the Spanish Central Range to determine the human influence. Although it is a mountainous area, where the presence of synanthropic species should be lower than in territories with a strong human impact, we have identified a minimum of 20.7% of the plants favoured by human action, including alien (6.2%) and strict ruderals (14.5%), which may increase to 39.2% including plants growing both in ruderal and non-ruderal habitats. The entrance of ruderal and alien plants continues currently, especially through roadsides, and probably increases in the future, due to growing tourism and to climate change, which may influence the patterns of colonization and invasion of ruderal and alien plants, and the response of the native flora. [ABSTRACT FROM AUTHOR]

Alien plants from psammophilous ecosystems have been studied in southern Spain. Sixteen sites, which are included in the Andalusian Network of Protected Spaces, have been chosen along 1100km of Andalusian coasts in order to verify the degree of abundance and influence of these species on different communities. Out of the 26 localized species, the increase of some invasive plants, such as Arctotheca calendula, Agave americana, A. sisalana, Cortaderia selloana, Lantana camara and Opuntia dillenii, affects the conservation of some natural coastal ecosystems. [ABSTRACT FROM AUTHOR]

Roads have become one of the main corridors supporting the dispersal of alien plants and their penetration and integration into native vegetation communities in new areas. The aim of this study was to use data sampled in 1970, 1994, and 2010 in order to check for changes in the spread of alien species along roadsides in relation to the adjacent land use. The results show that nutrient influxes and mechanical disturbance associated with the onset of intensive farming had a significant impact on the spread of the plant species in this study. In general, a significant increase was documented in the spread of species of invasive status. A different trend in the spread of archaeophytes and neophytes was observed in cases in which a road was adjacent to the meadow. Most of the archaeophytes in these habitats spread significantly in the first 20 years, and the distribution of neophytes did not show an increasing tendency. The highest rate of expansion was observed for plants propagating only by seed and in the built-up area of municipalities. Plants exhibiting both seed and vegetative propagation prevailed in the vicinity of meadows and forest vegetation. [ABSTRACT FROM AUTHOR]

Acacia salignais a phanerophyte native to Australia; it was introduced in the 1950s in Sardinia (Italy) for afforestation mainly in coastal areas and at present it is considered naturalized, becoming invasive in sand dune habitats. Seed biology is one of the most important factors contributing to the invasion success of Australian acacias, for this reason the germination ability is an important issue when trying to clarify the invasion dynamics ofA. saligna. Germination tests were conducted at the BG-SAR, testing the effect of different temperatures and percentages of NaCl, on seeds belonging to five accessions from four populations of two coastal habitat types. The optimal temperature range for seed germination was 15–20°C; the increase of salt caused a decrease in the final germination percentages. At 1% of NaCl concentration, germination fell at 25–30°C and at 2% it was relatively low (below 40%) and occurred almost only at 15°C. This work represents a contribution to the knowledge of the seed ecology and germination behaviour of the species, providing new data on the interpopulation and interannual variability, and relating them to the invasion dynamics ofA. salignain the coastal Mediterranean habitats. [ABSTRACT FROM AUTHOR]

Recent studies highlight the importance of selecting the appropriate scale and indices of invasion level for evaluating the abundance and impact of alien plants. Our survey considers the use of vegetation plot databases compared with floristic checklists to address invasion patterns regarding alien–native relationships across vegetation types by means of a multi-scale approach. We analysed the alien–native richness relationship in 1077 vegetation plots from the Basque Country (N. Spain) at ecosystem level and phytosociological class and alliance levels. According to our results, the alien species richness (Alo)–native species richness (Nat) relationship is variable and depends not only on the scale but also on the vegetation type. In contrast with other multi-scale approaches, no negative correlation has been detected at any studied level. The strong correlation existing between plot number and cumulative Alo and cumulative Nat highlights the constraints of using checklists to generalize invasion patterns. Our results demonstrate that the combined use of both relative alien species richness and relative alien species cover facilitates the understanding of invasion patterns across plant communities at different scales. In addition to climate, disturbance and propagule pressure, habitat type proved to be an important filter for alien species, capable of explaining such patterns. [ABSTRACT FROM PUBLISHER]

Seventy phytosociological releves were performed in 1 m × 1 m plots at 14 study sites spread along sandy shores in northern and southern Sardinia (Italy). The plots were selected in different habitat types (open dunes, native Juniperus woodlands, maquis, and plantations with Acacia, Eucalyptus and Pinus) according to a stratified sampling method in order to investigate impacts deriving from different levels of Carpobrotus spp. cover, dry litter from exotic trees, and other disturbance types. The quantile regression and logistic regression analyses revealed that the reduction in the amount of bryophyte and lichen cover on sand dunes of the study area is caused either by a high cover of Carpobrotus spp. mats or by a high cover of dry exotic litter in dense, unmanaged or poorly managed forest plantations. Additional detrimental effects are often driven by other kinds of man-made disturbances. Forest management in the coastal areas of Sardinia should be gradually modified to take into account the conservation of bryophytes and lichens. Some of the biological indicators used are quite widespread in the Mediterranean coastal habitats or are exclusively associated with sand dunes; therefore, they can also be conveniently used as indicators of biological impacts in other countries or islands of the same biogeographical region. [ABSTRACT FROM AUTHOR]