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Marini L.,Swedish University of Agricultural Sciences | Marini L.,University of Padua | Bertolli A.,Sezione Botanica | Bona E.,Centro Studi Naturalistici Bresciani | And 4 more authors.
Global Ecology and Biogeography | Year: 2013

Aim: Our aims were: (1) to separately evaluate the elevational patterns of β-diversity for nestedness, species richness difference and replacement, (2) to identify the drivers of β-diversity patterns by testing the effect of geographical and environmental distance (human population, temperature and land-use), and (3) to compare the response on native versus alien species to elucidate mechanisms of community assembly along elevational gradients. Location: Two mountain regions (Bergamo-Brescia and Trento) in the Italian Alps. Methods: We used two floristic datasets in which species composition was sampled within two regular grids. First, we extracted species elevational range and quantified species composition nestedness along the elevational gradient. Second, we partitioned β-diversity into its species richness difference and replacement components and tested drivers using regression on distance matrix and hierarchical partitioning. All analyses were performed on natives and aliens, separately. Results: For aliens, we found lack of mountain specialists (i.e. species with a distribution range restricted to high elevations), large nestedness, large species richness difference and low species replacement between low and high elevations. All findings point in the same direction: a great majority of alien species were introduced to the lowlands and only a subset of this community spread up the mountains. Both human pressures and temperature selection were important processes underpinning the observed filtering, while geographical and land-use distances were not important. Natives present contrasting patterns with large replacement along the elevation gradients indicating different mechanisms of community assembly. Main conclusions: The relatively large alien species replacement in the lowlands indicated the presence of a pool of species that may potentially invade the temperate mountains in the future. Investigations of the identity of alien species occurring in the lowlands and their climatic pre-adaptation might provide tools to prevent invasions in the mountains by predicting the potential invaders and their future elevational distribution. © 2012 Blackwell Publishing Ltd. Source


Marini L.,University of Padua | Bona E.,Centro Studi Naturalistici Bresciani | Kunin W.E.,University of Leeds | Gaston K.J.,University of Sheffield
Journal of Biogeography | Year: 2011

Aim- (1) To explore the impact of land use, climate and environmental heterogeneity on fern species richness along a complete elevational gradient, and (2) to evaluate the relative importance of the three groups of variables within different elevational intervals.Location- A temperate mountain region (55,507-km2) of Italy on the southern border of the European Alps divided into a regular grid of 1476 cells (grain 35.7-km2).Methods- We applied multiple regression (spatial and non-spatial) to determine the relative influence of the three groups of variables on species richness, including variation partitioning at two scales. We considered the whole gradient (all 1476 cells) to explain the overall elevational pattern of species richness, and we grouped the cells into elevational intervals of 500-m in order to evaluate the explanatory power of the predictors within different zones along the gradient.Results- Species richness showed a hump-shaped pattern with elevation, forming a plateau between 800 and 1500-m. The lowest species richness was found in warm and relatively dry disturbed lowlands. Moving upwards, the greatest species richness was found in forest-dominated mid-elevations with high environmental heterogeneity. At high elevations dominated by open natural habitats, where temperature and precipitation were relatively low, species richness declined but less sharply than in the lowlands. Although it was impossible to separate the effects of the three groups of predictors along the whole gradient, the analysis of separate elevational intervals shed light on their relative importance. The decline of species richness within lowlands was mainly related to a combined effect of deforestation and low environmental heterogeneity. In the middle part of the gradient, habitat heterogeneity and topographic roughness were positively associated with species richness. The richness decline within high-elevation areas was related mostly to climatic constraints.Main conclusions- Human impact due to land-use modifications strongly affects the elevational pattern of species richness. It is therefore increasingly important to adopt a multiple-hypothesis approach, taking anthropogenic effects explicitly into account when describing ecological processes along elevational gradients. © 2010 Blackwell Publishing Ltd. Source


Fenaroli F.,Centro Studi Naturalistici Bresciani | Pistarino A.,Museo Regionale di Science Naturali | Cellinese N.,University of Florida
Phytotaxa | Year: 2013

Campanula martinii a new species in the C. rotundifolia species complex, is here described. C. martinii is seemingly endemic to dolomitic cliffs and rocky places of the Prealps in Lombardia and Trentino-Alto Adige (northern Italy). The plants are robust with long hypogeal stolons, papillose ovary and patent to reflexed calyx teeth. This species is hexaploid with chromosome number 2n = 102. The taxonomic and phylogenetic placement of the new species is briefly discussed. © 2013 Magnolia Press. Source


Marini L.,University of Padua | Battisti A.,University of Padua | Bona E.,Centro Studi Naturalistici Bresciani | Federici G.,F.A.B. Gruppo Flora Alpina Bergamasca | And 3 more authors.
Global Ecology and Biogeography | Year: 2012

Aim To investigate whether differences in the elevational trend in native and alien species richness were dependent on climate or human pressures. Specifically we tested whether life-form and/or alien/native status modifies the response of plant species richness to human population and temperature along: (1) a complete elevational gradient, and (2) within separate elevational bands that, by keeping temperature within a narrow range, elucidate the effects of human pressures more clearly. Location Two provinces (c.7507km 2) on the southern border of the European Alps (Italy), subdivided into 240 contiguous sampling cells (c.35.7km 2). Methods We used an extensive dataset on alien and native species richness across an elevation gradient (20-2900m a.s.l.). Richness of natives and naturalized aliens were separately related to temperature, human population and Raunkiaer life-form using general linear mixed models. Life-form describes different plant strategies for survival during seasons with adverse cold/arid conditions. Results The relationship between species richness and temperature for natives was strongly dependent on life-form, while aliens showed a consistent positive trend. Similar trends across alien and native life-forms were found for the relationship between species richness and human population along the whole gradient and within separate elevational bands. Main conclusions The absence of life-form-dependent responses amongst aliens supports the hypothesis that the distribution of alien plant species richness was more related to propagule pressure and availability of novel niches created by human activities than to climatic filtering. While climate change will potentially contribute to relaxing species thermal constraints, the response of alien species to future warming will also be contingent on changes in anthropogenic pressures. © 2011 Blackwell Publishing Ltd. Source


Gentili R.,University of Milan Bicocca | Gilardelli F.,University of Milan Bicocca | Bona E.,Centro Studi Naturalistici Bresciani | Prosser F.,Museo Civico di Rovereto | And 33 more authors.
Plant Biosystems | Year: 2016

The spread of the invasive and allergenic Ambrosia artemisiifolia L. in Italy was analysed and mapped using distribution data from a wide range of sources. Ambrosia artemisiifolia occupies 1057 floristic quadrants which are mostly distributed in the Po plain. The distribution obtained represents the basis to implement urgent management strategies. © 2016 Società Botanica Italiana Source

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