• Energy Research

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. In order to draw insights on the association between plant functional traits and direct and indirect human and natural pressures on the environmental drivers, here we summarize the existing knowledge on this topic by reviewing the results of studies performed in Italy adopting a functional trait approach on vascular plants, briophytes 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 highlighting the need of 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.

Sulfur is an essential macronutrient for plant primary metabolism. Its availability can modulate plant growth in most terrestrial ecosystems. However, its relationship with other leaf and nutrient traits, and hence its contribution to plant functioning, remains unclear. We analysed leaf and nutrient traits for 740 vascular plant species growing in a wide range of environmental conditions in Northern Italy. We determined whether leaf sulfur content per unit leaf dry mass (LSC) is associated with leaf economics spectrum, and whether its distribution among functional types (growth forms, leaf life span categories, and Grime’s CSR (Competitive, Stress-tolerant, Ruderal strategies) could help to elucidate adaptive differences within plant taxa. High LSC values were mainly associated with fast-growing species representative of R- and C- strategy selection, thus the acquisitive extreme of plant economics, reflecting strong potential connections with ecosystem properties such as biomass production or litter decomposability. In general, LSC was significantly and positively correlated with leaf nitrogen content, and nitrogen to sulfur ratio was constant throughout growth forms, leaf life span and CSR strategies, and phylogenetic effects were evident. Our findings highlight that LSC variation is strongly associated with the leaf economics spectrum, suggesting that additional nutrients seldom included in functional analyses may also be embroiled within the context of plant economics. However, different ratios among nitrogen and sulfur may be expected across different plant families, suggesting that deeper insight from functional groups can provide a bridge between plant stoichiometry and ecology, useful for the evaluation of ecological responses to global change.

Fibrous and pioneer roots are essential in the uptake and transport of water and nutrients from the soil. Their dynamic may be influenced by the changing of soil physicochemical properties due to the addition of biochar, which, in turn, has been shown to improve plant growth and productivity in the short term. However, the long-term effects of biochar application on root dynamics are still widely unknown. In this study, we aimed to investigate the long-term effects of biochar application on grapevine fibrous and pioneer root dynamics and morphological traits in relation to soil characteristics. To this aim, grapevine plants amended in 2009 and 2010 respectively with one and two doses of biochar, were analyzed in their fibrous and pioneer root production and turnover rate, standing biomass, length, and specific root length, over two growing seasons. Our findings demonstrate that in the long term, biochar application significantly increased soil pH, nutrient availability, and water-holding capacity causing a decrease in the production of fibrous and pioneer roots which is reflected in a reduction of the root web characterized though by a higher turnover rate. Furthermore, we observed that these root morpho-dynamical changes were of higher magnitude in the upper soil layers (0-20 cm) and, at least in the long term, with no significant difference between the two doses. These results suggest that in the long term, biochar can be a powerful tool for improving soil quality, which in turn lowers carbon-cost investment toward the root production and maintenance of a reduced root web that might be directed into grapevine growth and productivity. Such effects shed some light on the root plastic and functional adaptation to modified soil conditions facilitated by the long-term application of biochar, which can be used for implementing adaptive agricultural practices to face the current climate change in a frame of sustainable agricultural policies.

Invasive alien plant species (IAPS) threaten ecosystem integrity worldwide. IAPS eradication is expensive, and their biomass is considered waste. Producing biochar from IAPS biomasses could turn waste into a resource. At the same time, this material could be used to remediate polluted soils. Also, using widespread native weeds, such as Urtica dioica (U), as an additional amendment could further improve soil remediation. In a phytoremediation experiment, we applied biochar produced from two widespread IAPS' biomass, i.e. Ailanthus altissima (Mill.) (BA) and Solidago gigantea Aiton (BS), at different rates (2 % and 5 % w/w) together with Urtica dioica L. powder (U) (2 % w/w) in an Arsenic (As) and Lead (Pb)-contaminated soil, using Phaseolus vulgaris L. as an indicator plant species. We measured the amendment's effects on soil pore water (SPW) properties, plant and fine root development, and soil enzymatic activities. When BS was added alone, and when BA was combined with U SPW's pH and electrical conductivity (EC) increased and [Pb] diminished, which augmented plant growth and reduced Pb uptake. Combining the biochar types and U increased the soil's enzymatic activities, fine root length, biomass, and specific root length. Finally, both biochar types with U increased As mobility in SPW, leading to higher plant uptake in roots, although without translocation to aboveground organs. Our findings contribute to developing cost-effective and environmentally sustainable practices for managing polluted soil. Simultaneously, they tackle the problem of IAPS, which can be used in the future to provide guidelines for policymakers.

Continental Antarctica represents the last pristine environment on Earth and is one of the most suitable contexts to analyze the relations between climate, active layer and vegetation. In 2000 we started long-term monitoring of the climate, permafrost, active layer and vegetation in Victoria Land, continental Antarctica. Our data confirm the stability of mean annual and summer air temperature, of snow cover, and an increasing trend of summer incoming short wave radiation. The active layer thickness is increasing at a rate of 0.3 cm y ^−1 . The active layer is characterized by large annual and spatial differences. The latter are due to scarce vegetation, a patchy and very thin organic layer and large spatial differences in snow accumulation. The active layer thickening, probably due to the increase of incoming short wave radiation, produced a general decrease of the ground water content due to the better drainage of the ground. The resultant drying may be responsible for the decline of mosses in xeric sites, while it provided better conditions for mosses in hydric sites, following the species-specific water requirements. An increase of lichen vegetation was observed where the climate drying occurred. This evidence emphasizes that the Antarctic continent is experiencing changes that are in total contrast to the changes reported from maritime Antarctica.