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Soil quality is fundamental for ecosystem long term functionality, productivity and resilience to current climatic changes. Despite its importance, soil is lost and degraded at dramatic rates worldwide. In Europe, the Mediterranean areas are a hotspot for soil erosion and land degradation due to a combination of climatic conditions, soils, geomorphology and anthropic pressure. Soil organic carbon (SOC) is considered a key indicator of soil quality as it relates to other fundamental soil functions supporting crucial ecosystem services. In the present study, the functional relationships among SOC and other important soil properties were investigated in the topsoil of 38 sites under different land cover and management, distributed over three Mediterranean regions under strong desertification risk, with the final aim to define critical SOC ranges for fast loss of important soil functionalities. The study sites belonged to private and public landowners seeking to adopt sustainable land management practices to support ecosystem sustainability and productivity of their land. Data showed a very clear relationship between SOC concentrations and the other analyzed soil properties: total nitrogen, bulk density, cation exchange capacity, available water capacity, microbial biomass, C fractions associated to particulate organic matter and to the mineral soil component and indirectly with net N mineralization. Below 20 g SOC kg−1, additional changes of SOC concentrations resulted in a steep variation of all the analyzed soil indicators, an order of magnitude higher than the changes occurring between 50 and 100 g SOC kg−1 and 3–4 times the changes observed at 20–50 g SOC kg−1. About half of the study sites showed average SOC concentration of the topsoil centimetres

Precision forestry is becoming a key sector for forest planning because it allows complex analyses of forest data to be carried out simply and economically. It contributes to the integration between technicians and operators in the sector by guaranteeing the transparency of the forest management operations (Corona et al., 2017). In the context of the progressive development of technology, we investigated the feasibility of using the hand-held mobile laser scanner (HMLS) system in different types of forest sites and comparison of the characteristics of individual trees (tree height, diameters at breast height) with traditional surveys, applied with the aim to validate the performance of the system for a future alternative methodology for forest planning thanks to the collaboration with the forestry company “Dimensione Ricerca Ecologia Ambiente Italia” (D.R.E.Am. Italia). GEOSLAM ZEB HORIZON ™ laser scanner is a hand-held mobile laser scanner containing SLAM technology that can be solved the problem of no GNSS signal or poor signal under the forest canopy making it more practical for forest investigations (Gollob et al., 2020). 15 forest sample plots are selected to reflect different stand conditions in Mediterranean forests taking into count the development stage and density of the sub-canopy vegetation, as well as the species composition in the forest stands. The aim of this study is to show the possible extrinsic circumstances that make the method fail by varying the ecological status of forest plots.

Made available in DSpace on 2020-12-12T02:34:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Università degli Studi di Palermo Ministero dell’Istruzione, dell’Università e della Ricerca Vegetation natural regeneration after agricultural abandonment is changing the landscape patterns in many areas worldwide. However, the expansion rate, spatio-temporal dynamics, and the role of past vegetation cover in shaping such patterns are still barely quantified in fine and meso scales. Here, we aim to quantify the expansion rate and assess the spatio-temporal patterns and the effects of past cover on natural woody vegetation cover increase. We sampled woodland and shrubland cover from 1992 to 2016 in 30 ha in a formerly managed pastureland in Sicily, Italy. We combined field sampling, GIS tools, and spatial analysis to assess the spatial structure dynamics and test the effects of past cover amount and type and distance from forest or nearest woody patch on the proportional expansion of natural regeneration. After 24 years, woody cover increased 68%, despite the aggregated spatial structure in 1992 remaining almost unchanged in 2016. The past vegetation cover was the best predictor of woody vegetation expansion in two out of three plots. Distance to continuous forest and to the nearest woody patch, as well as cover type, was not relevant. Our study highlights the importance of fine- and meso-scale studies to reveal both the deterministic and stochastic facet of woody vegetation dynamics. Natural regeneration may strongly change landscape patterns even under constant herbivory pressure and long-term deforestation. The detection of cold and hotspots of regeneration provide an important prompt for the design of restoration programs and landscape management. Dipartimento di Scienze Agrarie Alimentari e Forestali Università degli Studi di Palermo (UNIPA) Departamento de Ecologia Universidade Estadual Paulista (UNESP) Departamento de Biología de Organismos y Sistemas – UMIB University of Oviedo Departamento de Ecologia Universidade Estadual Paulista (UNESP) Ministero dell’Istruzione, dell’Università e della Ricerca: 201049EXTW

The occurrence of old-growth forests is quite limited in Mediterranean islands, which have been subject to particularly pronounced human impacts. Little is known about the carbon stocks of such peculiar ecosystems compared with different stages of secondary succession. We investigated the carbon variation in aboveground woody biomass, in litter and soil, and the nitrogen variation in litter and soil, in a 100 years long secondary succession in Mediterranean ecosystems. A vineyard, three stages of plant succession (high maquis, maquis-forest, and forest-maquis), and an old growth forest were compared. Soil samples at two soil depths (0-15 and 15-30 cm), and two litter types, relatively undecomposed and partly decomposed, were collected. Carbon stock in aboveground woody biomass increased from 6 Mg ha-1 in the vineyard to 105 Mg ha-1 in old growth forest. Along the secondary succession, soil carbon considerably increased from about 33 Mg ha-1 in the vineyard to about 69 Mg ha-1 in old growth forest. Soil nitrogen has more than doubled, ranging from 4.1 Mg ha-1 in the vineyard to 8.8 Mg ha-1 in old growth forest. Both soil parameters were found to be affected by successional stage and soil depth but not by their interaction. While the C/N ratio in the soil remained relatively constant during the succession, the C/N ratio of the litter strongly decreased, probably following the progressive increase in the holm oak contribution. While carbon content in litter decreased along the succession, nitrogen content slightly increased. Overall, carbon stock in aboveground woody biomass, litter and soil increased from about 48 Mg ha-1 in the vineyard to about 198 Mg ha-1 in old growth forest. The results of this study indicate that, even in Mediterranean environments, considerable amounts of carbon may be stored through secondary succession processes up to old growth forest. The occurrence of old-growth forests is quite limited in Mediterranean islands, which have been subject to particularly pronounced human impacts. Little is known about the carbon stocks of such peculiar ecosystems compared with different stages of secondary succession. We investigated the carbon variation in aboveground woody biomass, in litter and soil, and the nitrogen variation in litter and soil, in a 100 years long secondary succession in Mediterranean ecosystems. A vineyard, three stages of plant succession (high maquis, maquis-forest, and forest-maquis), and an old growth forest were compared. Soil samples at two soil depths (0-15 and 15-30 cm), and two litter types, relatively undecomposed and partly decomposed, were collected. Carbon stock in aboveground woody biomass increased from 6 Mg ha(-1) in the vineyard to 105 Mg ha(-1) in old growth forest. Along the secondary succession, soil carbon considerably increased from about 33 Mg ha(-1) in the vineyard to about 69 Mg ha(-1) in old growth forest. Soil nitrogen has more than doubled, ranging from 4.1 Mg ha(-1) in the vineyard to 8.8 Mg ha(-1) in old growth forest. Both soil parameters were found to be affected by successional stage and soil depth but not by their interaction. While the C/N ratio in the soil remained relatively constant during the succession, the C/N ratio of the litter strongly decreased, probably following the progressive increase in the holm oak contribution. While carbon content in litter decreased along the succession, nitrogen content slightly increased. Overall, carbon stock in aboveground woody biomass, litter and soil increased from about 48 Mg ha(-1) in the vineyard to about 198 Mg ha(-1) in old growth forest. The results of this study indicate that, even in Mediterranean environments, considerable amounts of carbon may be stored through secondary succession processes up to old growth forest.

Eucalyptus stands in semi-arid areas may contribute to enhance carbon (C) stocks in both biomass and soil. However, the limited information available is mainly focused on short-rotation plantations. In this study, the above- and below-ground C pools in five 50-year-old Eucalyptus camaldulensis Dehnh. stands planted on Miocenic evaporitic deposits in Sicily, Italy, with a xeric and thermic pedoclimate, were measured. Above-ground biomass was determined by partitioning and weighing branches, stem and leaves. Below-ground C pools included the determination of litter, root biomass, and soil organic and inorganic C. In terms of the above-ground biomass, the E. camaldulensis stand accumulated on average 116 Mg ha-1 corresponding to 55 Mg C ha-1. Below-ground biomass consisted mainly of larger roots, followed by fine and medium roots (33 Mg ha-1 corresponding to 14 Mg C ha-1). Litter accumulation on the soil surface accounted for 13 Mg ha-1 corresponding to 5 Mg C ha-1. The amount of C stored in soil was 554 Mg C ha-1, of which 75% was in organic form. Although E. camaldulensis is planted extensively throughout the Southern Hemisphere and tropics where it is managed over short rotations (c. 2–4 years), the results obtained from this study make this species important in terms of future afforestation planning for longer rotations due to its potential to sequester C, particularly in the below-ground components.

Abandonment of agricultural land leads to several consequences for ecosystem functions. Agricultural abandonment may be a significant and low cost strategy for carbon sequestration and mitigation of anthropogenic CO2 emissions due to the vegetation recovery and increase in soil organic matter. The aim of this study was to: (i) estimate the influence of different Soil Regions (areas characterized by a typical climate and parent material association) and Bioclimates (zones with homogeneous climatic regions and thermotype indices) on soil organic carbon (SOC) dynamics after agricultural land abandonment; and (ii) to analyse the efficiency of the agri-environment policy (agri-environment measures) suggested by the European Commission in relation to potential SOC stock ability in the Sicilian Region (Italy). In order to quantify the effects of agricultural abandonment on SOC, a dataset with original data that was sampled in Sicily and existing data from the literature were analysed according to the IPCC (Intergovernmental Panel on Climate Change) methodology. Results showed that abandonment of cropland soils increased SOC stock by 9.03MgCha−1 on average, ranging from 5.4MgCha−1 to 26.7MgCha−1 in relation to the Soil Region and Bioclimate. The estimation of SOC change after agricultural use permitted calculation of the payments for ecosystem service (PES) of C sequestration after agricultural land abandonment in relation to environmental benefits, increasing in this way the efficiency of PES. Considering the 14,337ha of abandoned lands in Sicily, the CO2 emission as a whole was reduced by 887,745Mg CO2. Therefore, it could be concluded that abandoned agricultural fields represents a valid opportunity to mitigate agriculture sector emissions in Sicily.

Mediterranean ecosystems are characterized by nearly complete replacement of natural vegetation by intensive croplands and orchards leading to strong soil degradation. Organic carbon is usually accumulated in soils under maquis leading to partial regeneration of fertility for future agricultural use. The aim of this work was to investigate the effect of land use change from maquis to agriculture on soil organic carbon (SOC) stock and its spatial distribution in a Mediterranean system. Three Mediterranean land use systems (seminatural vegetation, cactus pear crop and olive grove) were selected in Sicily and analysed for soil C stocks and their δ13C. Total SOC and δ13C were measured up to 75 cm soil depth within and between the rows of cactus pear and olive grove and along a similar transect in maquis, in order to evaluate the distribution of new and old C derived from roots. The land use change from Mediterranean maquis (C3 plant) to cactus pear (CAM plant) lead to a SOC decrease of 65% after 28 years of cultivation, and a further decrease for 14% after 7 years after the change from cactus pear to olive grove (C3 plant). Considering these SOC losses as well as the periods after the land use changes we calculated the mean residence time (MRT) of soil organic matter. The MRT of C under Mediterranean maquis was about 142 years, but was just 10 years under cactus pear. Root biomass of cactus pear was used for a new approach to estimate root turnover. The root turnover rate of cactus decreased along the soil profile from 7.1% per year in 0–15 cm to 3.7% in 60–75 cm soil depth. Along the transect, the average of root turnover values was highest in the middle of the intra-row. Root turnover and C input were correlated with SOC stocks to evaluate C sequestration potential of soils depending on land use and managements. We conclude that the SOC under maquis is higher and has longer residence time compared to permanent agricultural crops like cactus pear and olives.

The aim of this work was to investigate the effect of an experimental fire used for grassland management on soil organic carbon (SOC) stocks. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand & Schinz (Am) grasslands located in the north of Sicily. Soil samples were collected at 0–5 cm before and after the experimental fire, and SOC was measured. During the grassland fire, soil surface temperature was monitored. Biomass of both grasses was analysed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation type, while it is not affected in the short term by grassland fire. Am grassland stored more SOC compared with Hh grassland thanks to lower content in the biomass of the labile carbon pool. No significant difference was observed in SOC before and after fire, which could be caused by several factors: first, in both grassland types the measured soil temperature during fire was low due to thin litter layers; second, in a semiarid environment, a higher mineralization rate results in a lower soil carbon labile pool; and third, the SOC stored in the finest soil fractions, physically protected, is not affected by fire.

One of the most outstanding issues of current environmental research is the need of reliable assessments of carbon stock (i.e. above-ground (a.g.) and below-ground biomass, deadwood, litter, and organic soil matter) within forest ecosystems. Although shrub vegetation plays an important role in accumulating carbon in many Mediterranean environments, there is still very little knowledge on the carbon they store. In this article, we analyze the a.g. carbon stock of several Mediterranean shrubby communities in Sicily (Italy), dominated by Pistacia lentiscus, Chamaerops humilis, Euphorbia dendroides and Spartium junceum. Plant samples for each species were selected, and morphometric attributes (height, crown diameter, diameter at breast height, etc.) were measured to establish models for estimating a.g. biomass. Dendrometric data were also used to support the assessment of shrub biomass at community level by coupling them with the coverage of the considered woody species estimated from several hundreds of phytosociological releve´s carried out on pre-forest Sicilian communities. Although the results of such an approach have to be considered as rough assessments, the trial proves interesting, given the lack of information on stand biomass of pre-forest vegetation within the Mediterraean region. L'articolo è disponibile sul sito dell'editore http://www.tandfonline.com

The mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in the functioning of the ecosystem, as they regulate the cycle of soil organic matter (SOM) and CO2 emission into the atmosphere. In this study the contribution of litters of different stages of Mediterranean secondary succession on carbon sequestration was investigated, analyzing the role of earthworms in the translocation of SOM into the soil profile. For this purpose the δ13C difference between meadow C4-C soil and C3-C litter was used in a field experiment. Four undisturbed litters of different stages of succession (45, 70, 100 and 120 since agriculture abandon) were collected and placed on the top of isolated C4 soil cores. The litter contribution to C stock was affected by plant species and it increased with the age of the stage of secondary succession. One year after the litter position, the soil organic carbon increased up to 40% in comparison to soils not treated with litter after 120 years of abandon. The new carbon derived from C3 litter was decomposed and transferred into soil profile thanks to earthworms and the leaching of dissolved organic carbon. After 1 year the carbon increase attributed to earthworm activity was 6 and 13% in the soils under litter of fields abandoned for 120 and 45 years, respectively.

Clarifying which factors cause an increase or decrease in soil organic carbon (SOC) after agricultural abandonment requires integration of data on the temporal dynamics of the plant community and SOC. A chronosequence of abandoned vineyards was studied on a volcanic island (Pantelleria, Italy). Vegetation in the abandoned fields was initially dominated by annual and perennial herbs, then by Hyparrhenia hirta (L.) Stapf, and finally by woody communities. As a consequence, the dominant photosynthetic pathway changed from C3 to C4 and then back to C3. Conversion of a plant community dominated by one photosynthetic pathway to another changes the 13C/12C ratio of inputs to SOC. Using the time since abandonment and the shift in belowground δ13C of SOC relative to the aboveground δ13C plant community, we estimated C3-C and C4-C changes during secondary succession. SOC content (g kg− 1) increased linearly (R2 = 0.89 and 0.73 for 0–15 and 15–30 cm soil depth) with the age of abandonment, increasing from 12 g kg− 1 in cultivated vineyards to as high as 26 g kg− 1 in the last stage of the succession. δ13C increased in the bulk soil and its three aggregate fractions (> 250, 250–25, and < 25 μm) during succession, but the effect of soil depth and its interaction with succession age were significant only for soil aggregate fractions. Polynomial curves described the change in δ13C over the chronosequence for both depths. δ13C in the bulk soil had increased from − 28‰ to − 24‰ by 35 years after abandonment for both depths but then decreased to − 26‰ at 60 years after abandonment (corresponding with maturity of the woody plant community). Overall, the results indicate that abandoned vineyards on volcanic soil in a semi-arid environment are C sinks and that C storage in these soils is closely related to plant succession.

Ailanthus altissima is a well-known invasive tree in many parts of the world showing an outstanding ability to establish within woodlands and other less-disturbed habitats. Previous studies have reported that control of this species is very difficult because of its strong resprouting. Indeed, effective control can be achieved only by mechanical treatment followed by the application of a systemic herbicide. Operating drills or saws and other mechanical equipment require electric power supply which is not readily available in many invaded sites, notably shrubslands and woodlands. In two study sites, we evaluated control obtained by glyphosate through a stem-injection technique and compared two sources of power for the electric drill used. More than 90% of the glyphosate-treated trees in this study appeared to be dead just 1 month after treatments, and a car battery plus inverter was the most practical electrical source for drilling stems in the field.

We investigated the effects of woody plant colonization of abandoned pastures on soil and litter organic carbon (C) stocks and nitrogen (N) content along a bioclimatic transect in a semi-arid environment (Sicily, Italy). Soil samples were taken in three successional stages (grazed pasture, shrubland, forest) within each of three bioclimates (supramediterranean - “supra”, mesomediterranean - “meso”, thermomediterranean - “thermo”). Organic C and N in litter and soil (0-10 cm and 10-30 cm depth) were determined, as well as soil bulk density. Especially at 0-10 cm depth, changes in C and N contents along successional stages differed among bioclimates. Soil organic carbon (SOC) stock decreased from pasture to shrubland and increased from shrubland to forest in “supra”, increased from pasture to shrubland and then remained stable in “thermo”, and was stable in “meso”. Soil C/N ratio decreased with succession in “supra”, showed no significant trend in “meso”, and increased with succession in “thermo”. Litter C stock increased with succession in “meso”, increased from pasture to shrubland and decreased from shrubland to forest in “thermo”, and increased from pasture to shrubland and then remained stable in “supra”. Litter C/N ratio increased in “thermo” and “supra” from pasture to shrubland and from shrubland to forest, but did not change significantly with succession in “meso”. The different trends in SOC among bioclimates may be caused by changes in the importance of litter input, litter decay rate and mineralization. Successional changes in “meso” and “supra” appeared to be most affected by litter quality, while those in “thermo” appeared to be strongly influenced by limited litter decay due to low soil moisture and high temperature.

We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition, richness and evenness, and on the trend and speed of vegetation dynamics. Phytosociological releves of three different plot typologies, i.e. (1) soil-treatment and plantation, (2) only soil-treatment, (3) no soil-treatment and no plantation, were compared by (a) multivariate analysis and (b) with reference to species richness and evenness. Moreover, in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities, we compared life form and syntaxonomic spectra between phytosociological releves taken at 8 years of distance. DCA showed that floristic species composition and similarity are influenced by the canopy cover of Pine trees as well as by soil-treatment practices. Although species richness and evenness are not clearly related to neither soil treatment nor Pine afforestation, canopy cover clearly plays a major role: in fact, the highest Ph cover rates correspond to the lowest values of understory species richness. This is true also if only species of biogeographical/conservation interest are considered. Regarding vegetation dynamics, sites with dense Pine canopy cover evolve much slower than the adjacent garrigue communities. The same factors invoqued to explain the patterns of floristic composition and similarity (i.e. allelopathy and competition for light, water and nutrients) may also explain the lowering of diversity of therophytes and the strong decline of the cover perfomed by both therophytes and hemicryptophytes underneath the canopy of dense Ph plantations. Thus, in sites where Ph cover exceeds about 80%, thinning is recommended not only in order to accelerate succession, but also to give a natural ‘shape’ to afforestations.

This work investigated the effects of land cover and land-use change (LUC) on the ability of a soil to store carbon (C) and reduce carbon dioxide (CO2) emissions, in a Mediterranean area. Using a paired-site approach, we estimated the effect of land-cover change on the C stock from 1972 to 2008 in a natural reserve (Grotta di Santa Ninfa) in western Sicily. We selected 15 paired sites representative of five LUCs. We studied the effect of land use on soil organic C (SOC) content in bulk soil and in different particle-size fractions (2000–1000 µm, 1000–500 µm, 500–250 µm, 250–63 µm, 63–25 µm, and

Land use changes represent one of the most important components of global environmental change andhave a strong influence on carbon cycling. As a consequence of changes in economy during the last century, areas of marginal agriculture have been abandoned leading to secondary successions. The encroachment of woody plants into grasslands, pastures and croplands is generally thought to increase the carbon stored in these ecosystems even though there are evidences for a decrease in soil carbon stocks after land use change. In this paper, we investigate the effects of woody plant invasion on soil carbon and nitrogen stocks along a precipitation gradient (200–2,500 mm) using original data from paired experiment in Italian Alps and Sicily and data from literature (Guo and Gifford Glob Change Biol 8(4):345–360, 2002). We found a clear negative relationship (-0.05% C mm-1) between changes in soil organic carbon and precipitation explaining 70% of the variation in soil Cstocks after recolonization: dry sites gain carbon (up to? 67%) while wet sites lose carbon (up to -45%). In our data set, there seem to be two threshold values for soil carbon accumulation: the first one is 900 mm of mean annual rainfall, which separates the negative from the positive ratio values; the second one is 750 mm, which divides the positive values in two groups of sites. Most interestingly, this threshold of 750 mm corresponds exactly to a bioclimatic threshold: sites with\750 mm mean annual rainfall is classified as thermo-mediterranean sites, while the ones [750 mm are classified as mesomediterranean sites. This suggests that apart from rainfall also temperature values have an important influence on soil carbon accumulation after abandonment. Moreover, our results confirmed that the correlation between rainfall and trend in soil organic carbon may be related to nitrogen dynamics: carbon losses may occur only if there is a substantial decrease in soil nitrogen stock which occurs in wetter sites probably because of the higher leaching.

Clarifying which factors cause an increase or decrease in soil organic carbon (SOC) after agricultural abandonment requires integration of data on the temporal dynamics of the plant community and SOC. A chronosequence of abandoned vineyards was studied on a volcanic island (Pantelleria, Italy). Vegetation in the abandoned fields was initially dominated by annual and perennial herbs, then by Hyparrhenia hirta (L.) Stapf, and finally by woody communities. As a consequence, the dominant photosynthetic pathway changed from C3 to C4 and then back to C3. Conversion of a plant community dominated by one photosynthetic pathway to another changes the 13C/12C ratio of inputs to soil organic carbon (SOC). Using the time since abandonment and the shift in belowground δ13C of SOC relative to the aboveground δ13C plant community, we estimated SOC turnover rate. SOC content (g kg−1) increased linearly (R2 = 0.79 and 0.73 for 0–15 and 15–30 cm soil depth) with the age of abandonment, increasing from 12 g kg−1 in cultivated vineyards to as high as 26 g kg−1 in the last stage of the succession. δ13C increased in the bulk soil and its three fractions during succession, but only for soil fractions the effects of soil depth and its interaction with succession age were significant. Polynomial curves described the change in δ13C over the chronosequence for both depths. δ13C in the bulk soil had increased from −28 to −24‰ by 30 yr after abandonment for both depths but then decreased to −26‰ at 60 yr after abandonment (corresponding with maturity of the woody plant community). Overall, the results indicate that abandoned vineyards on volcanic soil in a semi-arid environment are C sinks and that C storage in these soils is closely related to plant succession.