No abstract

We explored the influence of climatic factors on diversity patterns of multiple taxa (lichens, bryophytes, and vascular plants) along a steep elevational gradient to predict communities’ dynamics under future climate change scenarios in Mediterranean regions. We analysed (1) species richness patterns in terms of heat-adapted, intermediate, and cold-adapted species; (2) pairwise beta-diversity patterns, also accounting for its two different components, species replacement and richness difference; (3) the influence of climatic variables on species functional traits. Species richness is influenced by different factors between three taxonomic groups, while beta diversity differs mainly between plants and cryptogams. Functional traits are influenced by different factors in each taxonomic group. On the basis of our observations, poikilohydric cryptogams could be more impacted by climate change than vascular plants. However, contrasting species-climate and traits-climate relationships were also found between lichens and bryophytes suggesting that each group may be sensitive to different components of climate change. Our study supports the usefulness of a multi-taxon approach coupled with a species traits analysis to better unravel the response of terrestrial communities to climate change. This would be especially relevant for lichens and bryophytes, whose response to climate change is still poorly explored.

In this article we propose a novel mathematical description of biomass growth that combines poroelastic theory of mixtures and cellular population models. The formulation, potentially applicable to general mechanobiological processes, is here used to study the engineered cultivation in bioreactors of articular chondrocytes, a process of Regenerative Medicine characterized by a complex interaction among spatial scales (from nanometers to centimeters), temporal scales (from seconds to weeks) and biophysical phenomena (fluid-controlled nutrient transport, delivery and consumption; mechanical deformation of a multiphase porous medium). The principal contribution of this research is the inclusion of the concept of cellular ''force isotropy'' as one of the main factors influencing cellular activity. In this description, the induced cytoskeletal tensional states trigger signalling transduction cascades regulating functional cell behavior. This mechanims is modeled by a parameter which estimates the influence of local force isotropy by the norm of the deviatoric part of the total stress tensor. According to the value of the estimator, isotropic mechanical conditions are assumed to be the promoting factor of extracellular matrix production whereas anisotropic conditions are assumed to promote cell proliferation. The resulting mathematical formulation is a coupled system of nonlinear partial differential equations comprising: conservation laws for mass and linear momentum of the growing biomass; advection-diffusion-reaction laws for nutrient (oxygen) transport, delivery and consumption; and kinetic laws for cellular population dynamics. To develop a reliable computational tool for the simulation of the engineered tissue growth process the nonlinear differential problem is numerically solved by: (1) temporal semidiscretization; (2) linearization via a fixed-point map; and (3) finite element spatial approximation. The biophysical accuracy of the mechanobiological model is assessed in the analysis of a simplified 1D geometrical setting. Simulation results show that: (1) isotropic/anisotropic conditions are strongly influenced by both maximum cell specific growth rate and mechanical boundary 123Meccanica (2017) 52: 3273-3297 DOI 10.1007/s11012-017-0638-9 conditions enforced at the interface between the biomass construct and the interstitial fluid; (2) experimentally measured features of cultivated articular chondrocytes, such as the early proliferation phase and the delayed extracellular matrix production, are well described by the computed spatial and temporal evolutions of cellular populations.

In dry habitats of European lowlands terricolous lichens and bryophytes are almost neglected in conservation practises, even if they may strongly contribute to biodiversity. This study aims at (a) testing the role of heathlands, acidic and calcareous dry grasslands for lichen and bryophyte diversity and conservation in lowland areas of northern Italy characterized by high human impact and habitat fragmentation; (b) detecting the effect of environmental drivers and vegetation dynamics on species richness and composition. Lichens, bryophytes, vascular plants, and environmental variables were recorded in 287 circular plots for 75 sites. Our results indicate that heathlands, acidic and calcareous dry grasslands host peculiar terricolous lichen and bryophyte communities that include several species of conservation concern. Thus, each habitat provides a complementary contribution to lichen and bryophyte diversity in continental lowland landscapes. Furthermore, in each habitat different factors drive species richness and composition with contrasting patterns between lichens and bryophytes. In terms of conservation, our results indicate that management of lowland dry habitats should act at both local and landscape scales. At local scale, vegetation dynamics should be controlled in order to avoid biodiversity loss due to vegetation dynamics and wood encroachment. At the landscape scale, patches of all the three habitats should be maintained to maximize regional diversity.

Aim To date, despite their great potential biogeographical regionalization models have been mostly developed on descriptive and empirical bases. This paper aims at applying the beta‐diversity framework on a statistically representative data set to analytically test the consistency of the biogeographical regionalization of Italian forests. Location Italy. Taxon Vascular plants. Methods Forest plant communities were surveyed in 804 plots made in a statistically representative sample of forest communities made by 201 sites of Italian forests across the three biogeographical regions of the country: Alpine, Continental, and Mediterranean. We conducted an ordination analysis and an analysis of beta‐diversity, decomposing it into its turnover and nestedness components. Results Our results provide only partial support to the consistency of the biogeographical regionalization of Italy. While the differences in forest plant communities support the distinction between the Alpine and the other two regions, differences between Continental and Mediterranean regions had lower statistical support. Pairwise beta‐diversity and its turnover component are higher between‐ than within‐biogeographical regions. This suggests that different regional species pools contribute to assembly of local communities and that spatial distance between‐regions has a stronger effect than that within‐regions. Main conclusions Our findings confirm a biogeographical structure of the species pools that is captured by the biogeographical regionalization. However, nonsignificant differences between the Mediterranean and Continental biogeographical regions suggest that this biogeographical regionalization is not consistent for forest plant communities. Our results demonstrate that an analytical evaluation of species composition differences among regions using beta‐diversity analysis is a promising approach for testing the consistency of biogeographical regionalization models. This approach is recommended to provide support to the biogeographical regionalization used in some environmental conservation polices adopted by EU.

Aim: In the last decades most European mountain forests have been abandoned after centuries of human management, paving the way for a landscape planning oriented to the conservation and rewilding of forest ecosystems. By resurveying historical vegetation plots in a mountain area of the Italian Apennines (southern Europe), we focused on yet overlooked processes in this area, to allow for a more comprehensive picture of the ongoing dynamics at a broad forest landscape scale. Location: Mountain forests in the northern Apennines, Italy. Methods: We resampled 22 historical forest vegetation plots recorded between 1934 and 1961. In each original quasi-permanent plot, three plots were sampled to improve the reliability of the comparison. We analyzed changes in forest cover, structure, alpha, beta, and gamma diversity, and ecological groups focusing on the understorey species community. Results: Forests are getting poorer in species in the understorey, with a higher tree layer and denser canopy cover. Alpha and gamma diversity significantly decreased from the original to the resurveyed plots. Several species of open habitats were associated with the original plots, while in the resurveyed plots several shade-adapted species were detected. Forest cover in the surroundings of the sites remained stable for the higher sites along the Apennines mountain ridge, while major changes in the surroundings and in species composition were detected for the plots located at lower elevations and marginal sites. Conclusions: Our main findings are in line with the majority of resurvey studies performed in European forests, with a general mesification of local communities after management cessation. Despite the limited number of available historical plots, their location along a wide gradient of elevation and naturalness allowed considering also the importance of site location, forest continuity and marginality as drivers of changes that need to be taken into account when planning conservation actions for restoration of mature forests.

The importance of collection, storage and exchange of georeferenced vegetation plot-based data has significantly grown in the recent decades, because of the new potentialities offered by ecoinformatics. In this article we introduce the Alma Mater Studiorum – University of Bologna vegetation database (AMS-VegBank; GIVD code EU-IT-021) compiling 17,505 georeferenced vegetation-plot observations within a time span of 90 years. This database includes 337,799 occurrence data of vascular plant species, belonging to many different habitat types. The historical relevance of the presented database is highlighted by the presence of some of the most ancient vegetation-plot observations in Europe (years 1930–1938). The geographic coverage of the database is mostly for Italian territory but it includes also data from other countries. The thematic focuses represented in the database are various, such as small Mediterranean islands, the Dolomite Mountains and the Italian National Parks. The large amount of historical plots available for the country not previously included in existing databases, combined with the constant action to improve the georeferencing of existing data and the addition of new data, highlight the uniqueness of this database. AMS-VegBank represents thus an important tool for studying plant biodiversity within the context of continental and global vegetation plot databases. Taxonomic reference: All plant names reported in this article follow the nomenclature by Pignatti et al. (2017–2019). Abbreviations: EVA = European Vegetation Archive; GIVD = Global Index of Vegetation-Plot Databases.

Sacred Natural Sites are relevant for biodiversity conservation, as in the case of forest sites that, across centuries, developed old growth structures and are now crucial for the conservation of epiphytic lichens and other specialized forest organisms. In this study, we investigated the epiphytic lichen flora of a small forest patch included in the Majella National Park (Abruzzo), whose old growth features and naturalness reflect its long lasting spiritual role that perfectly fits with the concept of Sacred Natural Site. Results revealed that the “Bosco di Sant’Antonio” hosts a rich and interesting epiphytic lichen flora, thus indicating the potential of this Sacred Natural Site for lichen conservation. Fifty-six species were found including two species newly recorded in Abruzzo, two red-listed species, and the sensitive species Lobariapulmonaria. This study corroborates the hypothesis that sacred forest sites are relevant for the conservation of specialized epiphytic lichens. In particular, in the Italian forest landscape where old-growth stands are practically absent, sacred forest sites may provide unique old-growth structures and buffer anthropogenic disturbance.