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Italy is among the European countries with the greatest plant diversity due to both a great environmental heterogeneity and a long history of man–environment interactions. Trait-based approaches to ecological studies have developed greatly over recent decades worldwide, although several issues concerning the relationships between plant functional traits and the environment still lack sufficient empirical evaluation. To draw insights on the association between plant functional traits and direct and indirect human and natural pressures on the environmental drivers, this article summarizes the existing knowledge on this topic by reviewing the results of studies performed in Italy adopting a functional trait approach on vascular plants, bryophytes and lichens. Although we recorded trait measurements for 1418 taxa, our review highlighted some major gaps in plant traits knowledge: Mediterranean ecosystems are poorly represented; traits related to belowground organs are still overlooked; traits measurements for bryophytes and lichens are lacking. Finally, intraspecific variation has been little studied at community level so far. We conclude by highlighting the need for approaches evaluating trait–environment relationship at large spatial and temporal scales and the need of a more effective contribution to online databases to tie more firmly Italian researchers to international scientific networks on plant traits. [ABSTRACT FROM AUTHOR]

In this study, we describe the seasonal variation in N abundance in the litter of two Sphagnum species and four vascular plant species during 3 years of field decomposition in an Italian Alpine bog. Litter bags were periodically retrieved at the end of summer and winter periods, and the δN in residual litter was related to mass loss, litter chemistry, and climatic conditions. In Sphagnum litter, higher rates of decomposition during summer months were associated with an increase of δN probably due to the incorporation of microbial organic compounds rich in N. The litter of Eriophorum vaginatum and Carex rostrata was characterized by a decrease of δN, so that the final signature was significantly lower than in initial litter. On the other hand, the residual litter of Potentilla erecta and Calluna vulgaris was characterized by a final δN higher than in initial litter. Our data reported a seasonality of N abundance in the residual litter of Sphagnum species, but not in that of vascular plant species, thus highlighting the role of differences in litter chemistry. [ABSTRACT FROM AUTHOR]

In the European Union, the Directive 92/43/EEC defines a number of species and habitats of community interest that are worthy to be preserved because in danger to disappear or because they are representative of the different European bio-geographical regions. In the light of the limited economic resources generally allocated to conservation efforts, there is the necessity to prioritise conservation actions in order to avoid deterioration of protected areas. To this aim, in the present study the most representative habitats of the Italian Alps are compared on the basis of vascular plant biodiversity and a conservation priority index is proposed for each habitat taking into account the potential distribution of 252 threatened vascular plant species. Rocky slopes, screes and alpine grasslands resulted to have the greatest percentage of endemic plant species so reflecting the general distributional pattern of endemic plant species at high altitudes in Eurasian mountains. The relationship between the conservation priority index and the corresponding habitat extent within the Natura 2000 network suggests that peatlands, arid grasslands, wet meadows and freshwater habitats deserve a higher priority in conservation actions. Although vascular plant biodiversity is not necessarily a surrogate of overall biodiversity of Alpine habitats, the results here reported can be used as an initial reference framework for prioritising conservation actions, so as to accomplish the provisions of Article 6 of Habitats Directive. [ABSTRACT FROM AUTHOR]

Variation of plant species cover on a Sphagnum-dominated mire in the south-eastern Alps of Italy was assessed over a 10-year period in relation to depth to the water table, peat accumulation rate, and climate. Population dynamics of vascular species appeared to be primarily affected by the autogenic process of peat accumulation, which determined the lowering of water-table position at microhabitat scale. Increase of depth to the water table through peat accumulation resulted in increased cover of ericaceous shrubs at previously moister microhabitats. Conversely, graminoid species such as Eriophorum vaginatum, Trichophorum caespitosum, and Scheuchzeria palustris, being negatively affected by autogenic peat growth, were forced to shift their niche towards the wetter end of the water-table gradient. Carex limosa and Carex rostrata decreased their cover along the whole gradient in depth to the water table, likely due to multiple processes related to peat accumulation, competition with bryophytes, and a negative feedback due to increased litter deposition. Bryophytes, in particular Sphagnum mosses, appeared more sensitive to climatic conditions, with higher precipitation favouring faster-growing species. Accordingly, Sphagnum fallax and Sphagnum magellanicum increased their cover much more than Sphagnum capillifolium, whereas Polytrichum strictum showed the strongest decrease at sites where S. magellanicum cover increased most. [ABSTRACT FROM AUTHOR]

The major environmental gradients underlying plant species distribution were outlined in two climatically and bio-geographically contrasting mires: a Swedish bog in the boreo-nemoral zone, and an Italian bog in the south-eastern Alps. Data on mire morphology, surface hydrology, floristic composition, peat chemistry and pore-water chemistry were collected along transects from the mire margin (i.e., the outer portion of the mire in contact with the surrounding mineral soil) towards the mire expanse (i.e., the inner portion of the mire). The delimitation and the extent of the minerotrophic mire margin were related to the steepness of the lateral mire slope which, in turns, controls the direction of surface water flow. The mineral soil water limit was mirrored in geochemical variables such as pH, alkalinity, Ca2+, Mg2+, Al3+, Mn2+, and SiO2 concentrations in pore-water, as well as Ca, Al, Fe, N and P contents in surface peat. Depending on regional requirements of plant species, different species were useful as fen limit indicators at the two sites. The main environmental factors affecting distribution of habitat types and plant species in the two mires were the acidity-alkalinity gradient, and the gradient in depth to the water table. The mire margin – mire expanse gradient corresponds to a complex gradient mainly reflected in a differentiation of vegetation structure in relation to the aeration of the peat substrate. [ABSTRACT FROM AUTHOR]

Summary 1 We assessed the role of climatic conditions and the effects of different, long-term atmospheric depositions in controlling the mineral and nutrient contents in pore-water, surface peat and in living Sphagna at a boreo-nemoral mire in Sweden and an alpine mire in Italy. 2 The terrestrial contribution of Ca2+ , Mg2+ and &formmu0; in bulk precipitation was much greater at the Italian mire, in accordance with the different bedrock in the region and the higher level of atmospheric pollution. 3 At both mires, the contribution of bulk precipitation to the concentration of major ions in mire pore-water was much greater in the ombrotrophic than in the minerotrophic part, because of the raised morphology of the mires, which limited the inflow of mineral soil water to the margins. The only ions strongly depleted in mire pore-water compared with precipitation were K+ , &formmu1; and &formmu2; and these were therefore limiting to plant growth. 4 Higher &formmu3; concentration in pore-water at the Swedish mire, which experienced lower atmospheric inputs of sulphate, was probably caused by oxidative processes during a long dry period in the summer before sampling. 5 Higher rates of &formmu4;, &formmu5;, as well as &formmu6; atmospheric inputs at the Italian mire were reflected in significantly higher N and, partly, S concentrations in ombrotrophic Sphagna. Higher &formmu7; concentration in pore-water at the Italian mire was associated with a lower N retention coefficient of the ombrotrophic Sphagnum plants, suggesting a reduced nitrogen filtering ability of the moss layer. [ABSTRACT FROM AUTHOR]

We determined trace metal concentrations in mature living tissues of the moss Hylocomium splendens, at different altitude, in the south-eastern Alps of Italy. We hypothesized that if precipitation does not vary with altitude trace element concentrations in moss tissues will not be affected by altitude. Contrary to our hypothesis, element concentrations did vary with altitude even in the absence of any precipitation pattern related to elevation. In particular, concentrations of anthropogenic pollutants (especially Cd and Pb) peaked at mid altitude (1400-1800 m) where frequency of cloud cover was the highest. We concluded that the trace metal concentrations in alpine mosses can be regarded as a reliable estimate of total atmospheric deposition, i.e., including occult deposition by cloudwater. The latter may account for a significant fraction of the total deposition of anthropogenic trace metals, in close relation to cloud cover frequency.

We studied the testate amoebae in the moss Hylocomium splendens along an altitudinal gradient from 1000 to 2200 m asl. in the south-eastern Alps of Italy in relation to micro- and macro-nutrient content of moss plants. Three mountainous areas were chosen, two of them characterised by calcareous bedrock, the third by siliceous bedrock. A total of 25 testate amoebae taxa were recorded, with a mean species richness of 9.3 per sampling plot. In a canonical correspondence analysis, 63.1% of the variation in the amoebae data was explained by moss tissue chemistry, namely by C, P, Ca, Mg, Al, Fe, and Na content and a binary site variable. We interpreted this result as an indirect effect of moss chemistry on testate amoebae through an influence on prey organisms. Although two species responded to altitude, there was no overall significant relationship between testate amoebae diversity or community structure and altitude, presumably because our sampling protocol aimed at minimizing the variability due to vegetation types and soil heterogeneity. This suggests that previous evidence of altitudinal or latitudinal effects on testate amoebae diversity may at least in part be due to a sampling bias, namely differences in soil type or moss species sampled.

Concentrations of aliphatic acids, phenolic acid, and inorganic nutrients, as well as hormone-like activity, were determined in soil dissolved organic matter (DOM) from two forest sites in N Italy showing differing degrees of silver fir regeneration. In the site where silver fir recruitment was abundant, humification processes prevailed, and the soil DOM had a high content in aliphatic and phenolic acids. This enhanced the hormone-like activity in the soil, which could in turn promote growth of silver fir seedlings. In the site with poor fir recruitment, the soil DOM underwent rapid mineralization and was richer in inorganic nutrients, but had lower concentrations of aliphatic and phenolic acids, and lower hormone-like activity.