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Background and aim: Litter decomposition is of great concern as it plays a key role in regulating global carbon cycle and nutrient budgets, especially in tropical forests where it is very fast. Therefore, we studied the decomposition and subsequent changes in element concentrations and amounts of 11 tropical leaf litter.Methods: Fresh litters were characterized in terms of elemental, proximate features, as well as organic carbon compositions by 13C-NMR spectroscopy. Controlled litterbag decomposition was carried out for 180 days in the laboratory, bags were retrieved at three dates and analyzed for mass loss and concentration of nitrogen (N), potassium (K), sodium (Na), carbon (C), magnesium (Mg), manganese (Mn), iron (Fe), phosphorus (P), zinc (Zn), and percentage of ash, extractives, cellulose and lignin.Results: Terminalia arjuna showed highest mass loss, while the lowest was observed in Shorea robusta showing significant positive correlation with litter initial K, Mg, Fe and di-O-alkyl C, O-alkyl C, while significant negative correlation with Mn, lignin and Methoxyl C, Alkyl C. Trajectories shows that Fe, Mg, K, Mn, Zn and Na concentrations increased in most of the litter types, except Terminalia arjuna and Toona ciliata, where Fe, Mg, K concentrations decreased during decomposition. Surprisingly, in most of the species with the exception of Terminalia arjuna, N concentrations decreased at a faster rate than C concentrations, resulting in an increase in C/N ratios. Expectedly, lignin progressively increased, while cellulose decreased.Conclusions: Observed differences in decomposition rate and dynamics of chemical changes among litters were strongly affected by the litter type, decomposition time and their interactions. [ABSTRACT FROM AUTHOR]

Aim: High‐elevation forest line or tree line is an ecological ecotone representing the upper elevation thermal limit for forest development. The current tree line position is the result of the past human activity interacting with climatic and topographic conditions. In this study, we investigate how climate, local topographic factors and anthropogenic disturbance currently affect tree line distribution. Location: Apennine Mountains, 900 km latitudinal gradient along the Italian Peninsula. Methods: Overall, 302 mountain peaks were studied, comprising 3,622 km of measured tree lines. The position of the Fagus sylvatica tree line in all peaks was assessed and correlated with 58 selected variables representing climate, topography and human disturbance. Results: The mean tree line elevation was 1,589 m a.s.l., with considerable variability among peaks. Contrary to our expectations, the tree line elevation was lower in the warmer southerly exposed slopes compared to north‐facing aspects, where we found the highest tree line (2,141 m a.s.l.). Correlation analysis indicates that both climatic and human density variables are associated with tree line elevation, with the climate having more influence in high elevation mountains, while human impact plays a prominent role in low elevation mountain peaks. Specifically, we found negative correlations between density of the resident population around each peak and tree line elevation at all examined dates (1861, 1921, and 2011), suggesting a pervasive negative impact of human activity on tree lines. As regards climatic variables, tree line elevation showed a stronger negative correlation with winter and spring months temperature than with mean annual temperature. Noteworthy, climatic variables had stronger effect on high elevation peaks (>1,900 m a.s.l.) compared with low elevation ones (<1,900 m a.s.l.). Main Conclusion: Our data provide evidence that the current position of the F. sylvatica tree line in the Apennines is heavily depressed as a result of a complex interaction between climatic factors and the past human pressure. [ABSTRACT FROM AUTHOR]

Abstract Biodeterioration, the alteration caused by living organisms, on historical buildings and stone monuments is a widespread problem affecting two-thirds of the world's cultural heritage. Deterioration and weathering of stone monuments are caused by abiotic, anthropogenic and microbial factors, with few studies focusing on the role of higher plants. In this study, we investigate how rock type, exposure and inclination of the wall, as well as current management, affect the biodeteriogenic vegetation at four stone monuments. For this purpose, we selected four castles situated in the province of Naples in southern Italy. For each castle, we analysed linear transects 1 m long (N = 74), representing the different associations of the main biodeteriogenic vascular plant species. The total number of plant species recorded was 28, belonging to 17 families. Floristic composition and hazard index (HI) varied greatly among the four study sites. Exposure, substrate type and surface inclination significantly affect floristic composition, with plant cover and HI highest on south-facing walls. As regards the rock substrate, HI was significantly higher on plaster, compared to piperno and tuffs. Finally, substrate inclination did not affect plant occurrences although the HI was significantly higher on horizontal surfaces than vertical ones. Our study revealed that the walls of four castles harboured specific flora, whose composition depends on local environmental factors, current management as well as the surrounding vegetation. The present findings concerning the colonisation capabilities of the main biodeteriogenic species provide useful insight to clarify the relationship between plant cover and hazard risk in the context of wall deterioration. Highlights • The plants growing on four castles situated in the province of Naples are studied. • Vegetation composition and hazard index varied greatly among the four study sites. • Exposure, substrate type and surface inclination affect vegetation composition. • Plant cover was significantly higher on plaster, compared to piperno and tuffs. [ABSTRACT FROM AUTHOR]

Complementary and alternative medicine (CAM) consists of systems and practices used to prevent or treat illness, and/or promote health and wellbeing, generally with herbal remedies. In recent decades, ethnobotanical and ethnopharmacological surveys have received increased attention among populations in central and southern Italy traditionally highly conservative regarding knowledge of folk medicine. This review highlights the use of wild and cultivated plants in paediatric health care. From a search of articles published between 1978 and 2017 we found a total of 34 containing reports of medicinal plants specifically used for treating children’s diseases, listing 83 taxa belonging to 37 families in 116 recorded cases of medicinal plant use. Tuscany has the highest number of plant use reports and the highest number of species used in a single region, followed by Campania and Sicily. Allium sativum is the most widely reported species, cited in eight regions. We identified eight ailment categories. Plants used as anthelmintics and for gastro-intestinal and skin diseases are widely used. [ABSTRACT FROM AUTHOR]

The organic matter cycle is one of the most fundamental processes in ecosystems affecting the soil and controlling its functions. The soil complex microbiome is made up of thousands of bacterial and hundreds of fungal strains that coexist on the many different available organic carbon sources. In natural plant communities, freshly fallen leaf-litter and dead roots are subject to decomposition by a complex food-web composed of both microbial saprotrophs and invertebrate detritivores. The litter chemical composition varies dramatically among species in relation to plant life forms (conifer, broadleaf, nitrogen-fixing, graminoid) and, within species, with plant organs (leaf, root, woody tissues). This paper reviews the usefulness of advanced chemical technologies to study the composition of both plant litter and organic amendments, supporting the description of their mechanism of action and attention to their potential applications. First, a critical review is presented on the limitations of C/N and lignin/N ratios, still widely used as basic indicators of litter chemistry. Second, the potential of the solid state 13C-CPMAS NMR is reported as a powerful tool to assess the chemical composition of both litter and organic amendments. Finally, six different study cases are reported to provide evidence of the usefulness of such metabolomic approach for the description of organic matter chemistry aimed to an effective prediction of its impact on soil ecosystem functions. [ABSTRACT FROM AUTHOR]

Plant invasion in forest ecosystems is a serious ecological and economic issue, deserving attention by researchers, managers and policy-makers worldwide. Many invasive plants have been reported as early successional species able to colonize disturbed areas following abrupt changes in microhabitat and resource availability. We investigated disturbance effects of a severe windstorm generated by a wet microburst (hail and rain at 160 mm h-1) remarkably affecting the canopy cover of an old-growth Quercus ilex urban forest in Southern Italy. This stand-replacing disturbance produced a mosaic of 103 gaps, 5.6 to 1632 m2 in size, over an area of 1.53 ha, uprooting 76% of the trees and decreasing thereby 85% of the standing above-ground dry biomass into the gaps. By intensive monitoring we compared above- and below-ground microclimate, soil moisture and mineral N availability in paired disturbed and control areas of the study forest. Within newly formed gaps we observed a seasonally consistent 70% higher content of nitrate nitrogen, 29% and 47% decreases of ammonia nitrogen in summer and autumn, respectively, and a higher moisture in topsoil, in addition to different above- and below-ground microclimatic conditions, with canopy cover mitigating extreme temperatures. One year after the windstorm, the microhabitat shift promoted the establishment in gaps of 15 native and 10 alien taxa previously absent in both disturbed and control plots. In such conditions, the rarefaction of the dominant Q. ilex canopy cover and the occurrence of empty niches prone to invasion could dramatically affect the local community structure and diversity. Our data indicate that stand-replacing windstorm can transiently transform the studied urban evergreen forest to an early allogenic successional community dominated, in the medium and large gaps, by annual and perennial non-native species. This is particularly relevant under a perspective of possible increasing frequency of windstorm events in the Mediterranean region in the near future. [ABSTRACT FROM AUTHOR]

Soil microbiome plays a critical role in maintaining key soil processes such as litter decomposition, nutrient cycling, and plant productivity. In this study, we aimed to investigate the variability of soil chemicals, microbial diversity, and composition in seven ecosystems i.e., Fagus sylvatica and Quercus ilex forests, a Mediterranean grassland and shrubland, a vineyard, a horticultural cultivation in open field and under greenhouse, across a gradient of land-use intensity in Southern Italy. Soil chemistry included pH, organic matter, total nitrogen, and C/N ratio, and soil microbiota was characterized by high-throughput sequencing of 16S and ITS genes. Our results showed that greenhouse soils had the highest pH, while Fagus had the lowest. Horticultural, greenhouse, and grassland soils had low levels of OM and total N, while shrubland had relatively high levels of OM, total N, and C/N ratio. Fagus soils, on the other hand, had the highest levels of OM, total N, and C/N ratio. Bacterial diversity was lowest in horticultural soils, whereas fungal diversity was highest in shrubland soils. Pseudomonadota were the predominant bacteria in Fagus , grassland, and vineyard soils, while Actinomycetota dominated in Quercus , shrubland, and greenhouse soils. However, Cyanobacteria was predominant in horticultural soils. On the other hand, the Ascomycota was predominant in all ecosystems except Quercus soils, where the Basidiomycota was dominant. Our bipartite network analysis revealed that bacteria are often the same in different ecosystems while fungi tend to be specific to a particular habitat. Moreover, in agricultural ecosystems, fungal pathogens belonging to Alternaria , Fusarium , Gibellulopsis , Stemphylium , Acremonium , and Curvularia are more abundant, especially in greenhouse. The findings of this study provide important insights into the variability of soil microbial diversity and community composition in different ecosystems, highlighting the essential role of preserving natural ecosystems while managing agricultural ones, given their higher abundance of pathogens. [Display omitted] • Four natural and three agricultural ecosystems were investigated. • Soils were characterized for chemistry and microbiota by next generation sequencing. • Microbial diversity and composition varied among ecosystems in relation to land use. • Land use intensity reduce microbial diversity and increase plant pathogen abundance. [ABSTRACT FROM AUTHOR]

Numerous recent studies have demonstrated that biochar may significantly reduce the incidence of plant diseases caused by airborne and soilborne pathogens, although contrasting results have also been reported. In this work, we investigated how biochar affects crop plant and soilborne microbe growth. Aims of this study were: i) to analyze the chemical changes occurring in four organic feedstocks (e.g. wood chips, organic urban waste, Zea mays residues, and Medicago sativa hay) when pyrolyzed at 300 °C and 550 °C by using 13 C NMR spectroscopy and SEM (Scanning Electron Microscopy); ii) to assess how biochar affects growth of five bacteria, nine fungi, and three crop plants; and iii) clarify the relationships between biochar chemistry and its effect on target species. As pyrolyzation temperature increased, organic matter chemistry of all products changed significantly, with a progressive loss of O -alkyl C, di- O -alkyl C, and methoxyl and N -alkyl C, coupled with an enrichment in aromatic C types. Untreated urban waste and Medicago hay severely inhibited Lepidium , Lactuca and Solanum root growth, whereas no inhibitory effects were found for the other feedstocks. However, these phytotoxic effects largely decreased after pyrolyzation. In contrast to the crop plants, fungi and bacteria thrive on most of the unprocessed organic materials but showed reduced growth and development or complete growth inhibition on biochars obtained at 300 °C and 550 °C. Soilborne microbes demonstrated remarkably similar correlation patterns between their growth to the organic feedstock and biochar chemical components. This work demonstrates that defining organic matter quality by 13 C NMR extends our understanding of the impact of biochar on crop plants and key components of the soil food-web. [ABSTRACT FROM AUTHOR]

Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. We tested the chemical convergence hypothesis, i.e., materials with different initial chemistry converge toward a common profile, with similar biological effects, as the oxidative process advances, for burning and decomposition. We compared the molecular composition, assessed by 13C NMR, of seven plant litter types either fresh, decomposed for 30, 90, 180 d in a microcosms incubation experiment, or heated at 100°C, 200°C, 300°C, 400°C, 500°C for 30 minutes. We used litter water extracts (5% dry weight) as treatments in bioassays on plant ( Lepidium sativum) and fungal ( Aspergillus niger) growth, and a washed quartz sand amended with litter (0.5% dw) to assess heterotrophic respiration by flux chamber (i.e., [μg of CO2 released]·[g added litter]−1·d−1). We observed different molecular variations for materials either burning (i.e., a sharp increase of aromatic C and a decrease of other fractions above 200°C) or decomposing (i.e., early increase of alkyl, methoxyl, and N-alkyl C and decrease of O-alkyl and di- O-alkyl C fractions). Soil respiration and fungal growth decreased with litter age and heating severity, down to 20% relative to fresh litter. Plants were inhibited on fresh litter (on average 13% of the control), but recovered on aged (180 d) and heated (30 min at 500°C) materials, up to 126% and 63% of the control, respectively. Correlation between the intensity of 13C NMR signals in litter spectra and bioassay results showed that O-alkyl, methoxyl, and aromatic C fractions are crucial to understand organic matter effects, with plant response negatively affected by labile C but positively associated to lignification and pyrogenic C. The pattern of association of soil respiration and fungal growth to these C fractions was essentially opposite to that observed for plant root growth. Our findings suggest a functional convergence of decomposed and burned organic substrates, emerging from the balance between the bioavailability of labile C sources and the presence of recalcitrant and pyrogenic compounds, oppositely affecting different trophic levels. [ABSTRACT FROM AUTHOR]