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Forests are among the most important land ecosystems both in term of their contribution to the global carbon cycle and for their prominence in hosting large biodiversity. Under a changing world, both in terms of land use and climate scenarios, it is pivotal to understand the matter and energy flows in complex ecosystems such as forests, in order to infer potential relationships at different levels, i.e. from soil to bird community within the forest stands. In this context, soil organic matter is main source of carbon and energy for heterotrophic soil organisms, which are a main component of the whole food web all the way up to bird communities. Even though many studies have investigated factors affecting C cycle and bird communities in forest ecosystems separately, an integrated approach that links soil to bird community was never attempted. Accordingly, we have used an innovative Two-block Partial Least Squares analysis to investigate patterns of covariance between soil and nesting bird communities in a relatively small wooded area surrounded by the urban area of Naples (southern Italy). Our research revealed that, in spite of the small extent and the surrounding urban context, the area of the Astroni hosts a substantial C stock and has a diversified bird nesting community. The abundance of species such as blue tit, jay, green woodpecker and great tit had a direct covariance with C stock in litter, while sampling sites that were characterized by greater C stocks in the soil and higher microbial activity were correlated with abundance of other bird species, most noticeably short-toed treecreeper and blackbird. Despite the limited extent of our research area, our study showed, for the first time, patterns of covariance between some forest species and different soil variables, linking forest ecological compartments whose connections are not immediately detectable and that could open new perspectives in land use management, both in terms of C stock and biodiversity evaluations.

Trace elements have been acknowledged as one of the subtlest environmental hazards in all compartments of the total environment. Enhanced by activities in the anthroposphere, they accumulate in the atmosphere, lithosphere, and hydrosphere. Eventually, trace elements can bioaccumulate or biomagnifiy in the biosphere, with harmful effects on animals occupying higher trophic levels, including humans. Accordingly, there is great interest in assessing and monitoring trace element concentrations in the biosphere, and birds, especially passerines, have been commonly chosen as biomonitors. In this study, the concentration of 11 trace elements was measured (i.e. aluminum, chromium, manganese, iron, nickel, copper, zinc, arsenic, cadmium, barium, and lead) in flight feathers of Italian Sparrows, a common bird species hitherto not analysed in this respect. Samples were collected in an agricultural area in southern Italy, where a mosaic of natural environments, urbanized areas and industrial facilities can be found. Linear mixed modelling was applied to the analysis of flight feathers in juveniles, juvenile birds moulting to adulthood, and adults in three sampling years on 184 birds. Results are timely as they add new data to the scarce available information on Ba and As in bird feathers and showed clear bioaccumulation patterns from juveniles to adults for As, Cr, and Cd. Moreover, the modelling approach showed that the concentration of elements such as As, Cd and Cr can be variable across the years and that some elements, notably Cd and Ba, were inversely correlated with body mass and wing length, respectively, suggesting potential negative effects on bird health. Finally, when modelling bird body condition and trace elements, results showed that Cd and Ba negatively affect birds regardless of age or sampling year. Thus, the Italian Sparrow could be considered as a valuable biomonitor for trace elements in the total environment, especially for Cd and Ba.

Agricultural soils generally have a low content of organic matter, which affects soil fertility and hence crop yields. The use of olive pomace as an organic amendment could enhance soil properties due to its high content of organic matter and exchangeable cations as well as its extensive availability. However, little is known about the potentially detrimental effects of salts and high content of phenolic substances that might occur over time with the use of pomace amendment in agricultural soils. Similarly, its impact on microbial communities and enzyme activities is largely unknown. To ascertain these effects, we tested the response of soil enzyme activities (β-glucosidase, urease, acid phosphomonoesterase and dehydrogenase) starting from a long-term (8-year) previously amended soil and a control (non-amended) soil and exposing these soils to a short-term (12-week) laboratory experiment. We also focused on soil organic matter and mineral N, on relating enzymatic data to bacterial and fungal biomasses, and on an index for soil functional quality based on enzyme activities (AI3). Our results show that organic matter, enzyme activities and the soil quality index were improved by long-term treatment with olive pomace, contrasting with scant effects from short-term laboratory incubation. In spite of its high content in salts and phenolic substances, no detectable negative impact emerged from the use of this amendment. Overall, olive pomace clearly increased soil organic matter and improved soil biological activity and quality, without any detectable negative effects.

This study reports a comparative analysis of soil enzyme activities (β-glucosidase, protease, urease, arylsulphatase, phosphatase and fluorescein diacetate hydrolase), ATP, total N and organic matter contents in three vegetal successional stages (meadow, low shrubland and high maquis) of a Mediterranean ecosystem in the Natural Reserve of Castel Volturno (Campania, Italy). Because water availability is a major limiting factor of soil microbial activity in Mediterranean ecosystems, the analysis was performed in late spring (May), after the rainy period, and in early autumn (October), after the long dry summer. A significant decrease in protease, arylsulphatase, urease and β-glucosidase activities was observed in meadow soil in the autumn sampling, probably due to the prolonged summer drought. Combining the values measured in the two sampling dates, the high maquis tended to have higher levels of enzymes activities than shrubland and meadow. Notably, high maquis had significantly higher phosphatase and arylsulphatase activities than shrubland and meadow and, in addition, a higher ATP content compared to meadow. Drastic changes were observed in EA/ATP ratios between the sampling periods in the meadow and shrubland, suggesting changes in the efficiency of microbial community more likely linked to climatic fluctuations than to the successional stage. The more stable EA/ATP ratio in the maquis probably reflects a constant contribution of microbial biomass to enzyme secretion. In conclusion, our results point to an increase in soil microbial activity accompanying the succession from meadow to high maquis that probably reflects a parallel increase in soil functions. Nevertheless, spatial heterogeneity and, more important, temporal variations in soil activities often may obscure differences related to the plant cover type. © 2009 Elsevier Ltd. All rights reserved.

Soil microbial activities and chemical properties related to the N cycle were investigated in function of variations in plant cover type in a Mediterranean area of Southern Italy. Several biological (microbial biomass, soil respiration, protease activity, degradation of 7 amino acids, net N mineralization, net nitrification, potential net nitrification and denitrification) and chemical properties (water content, pH, organic C, total and mineral N, C/N ratio) were determined in soil samples collected in spring and early autumn under three plant cover types (high maquis, low shrub community and meadow) epitomizing distinct successional stages following disturbance. Water content, organic C and C/N ratio were higher in soil from high maquis than in soils from the other plant cover types; in contrast, no difference was generally observed between the three soil types as for total and mineral N content. Likewise, no clear-cut difference was recorded for most of the tested biological parameters if these were expressed per unit of soil dry weight, with the exception of protease activity and soil respiration, which were significantly higher in the high maquis. However, when biological data were expressed per unit of organic C, meadow soil showed higher values of microbial biomass, asparagine degradation (only in spring), net mineralization and net nitrification (only in autumn) compared to the other soils. Statistical analysis pointed to seasonal fluctuation of water availability as an important limiting factor for microbial biomass and activity, with the exceptions of net N mineralization, net nitrification, glutamine and glutamic acid degradation activities which appeared to be mainly driven by organic matter content in soils. Overall, the results suggest that, in the investigated Mediterranean environment, variations in plant community ranging from meadow to high maquis produce little changes in soil biological activities linked to the N cycle, these being primarily affected by the availability of water and soil organic matter during the annual cycle. © 2009 Elsevier B.V. All rights reserved.

The patterns of microbial respiration and enzyme activity (cellulase, xylanase, laccase and peroxidase) in the leaf litter of two evergreen sclerophyll species, Myrtus communis and Quercus ilex, were compared during decay in a low shrubland and in a coppice wood in a Natural Reserve in the Mediterranean area. The two litter types had similar initial amounts of lignin, cellulose and acid-detergent-soluble substances, but the litter from M. communis had a lower N content and higher C/N ratio. In spite of this, the decomposition rate of M. communis litter was higher than for Q. ilex. Whilst no seasonal variation was observed in the rate of organic matter degradation, respiration and extractable cellulase and xylanase activities showed seasonal variation in both litter types with the highest values in winter-early spring and the lowest in summer, and showed positive correlations with water content. Peroxidase activity exhibited a seasonal pattern and was higher in Q. ilex than in M. communis, while laccase activity was higher in M. communis and increased with fungal biomass as degradation progressed. Nevertheless, no relationship was found between laccase and peroxidase activity and lignin degradation. The results obtained indicate that the seasonal alternation of moist and dry periods is the major factor influencing soil biological activity in the Mediterranean area. The occurrence of pronounced seasonal variation in litter enzyme activity prevents the determination of possible correlations with litter mass loss. © 2006 Elsevier B.V. All rights reserved.

The decomposition dynamics of the litters of Corsican pine ( Pinus laricio Poiret), Stone pine ( P. pinea L.) and Scots pine ( P. sylvestris L.) exposed in a Corsican pine forest in the South Italy Apennines were followed for 2.5 y. Litter decomposition was very slow for all three species and appeared to be limited mainly by the low water availability throughout the study. The microbial activity, expressed as respiration, and the fungal biomass were also low due to the low moisture content of the litters, as suggested by the high increase of the potential respiration, after their hydration. A highly significant and positive relationship between potential CO 2 evolution rates and litter moisture content was found. The decomposition dynamics were also affected by the initial chemical composition of the three litter types. A delay in starting decomposition and the lowest initial rate were observed in Stone pine litter, that had the highest initial N, but also the highest lignin content and the lowest initial Mn content.

The potential for nitrification is appreciable throughout the whole seasonal cycle, but nitrate is depleted at different rates during the year. The highest values of nitrate depletion occurred in late spring, early summer and at leaf-fall when readily available carbon substrates are released from root exudates or from litter decomposition. -from Authors

Nitrogen mineralization has been studied in the slightly acidic brown earth on limestone of a beech stand and a beech-fir stand, in the forests of Monte Taburno (Campania Apennines). NH4 is the predominant form of the mineral N in the soil of both stands. Yearly NO3- production is 42.4 kg ha-1 in the beech stand and 47.0 kg ha-1 in the beech-fir stand.-from Authors