Structural analysis of woody species in Mediterranean old fields.

The first part of this study provides an overview on Sicilian olive systems. Subsequently, the study describes the different typologies of cultivated agroforestry systems present in South-Eastern Sicily employing olive trees in association with other Mediterranean tree species, in particular for the production of firewood, coal and animal food (downy or pubescent oak, holm oak, cork oak), but also in association with forage or grazing species (oat, barley, vetch, etc.) or cereals. The study shows that Sicilian agroforestry systems are much more diversified than it was known so far. In the second part, the study describes the spontaneous colonization processes by plants, observed in abandone…

Vertebrate-mediated seed rain and artificial perches contribute to overcome seed dispersal limitation in a Mediterranean old field

Natural regeneration of vegetation is a frequent outcome of land abandonment, although the rate and diversity of such regeneration may be severely restricted by seed dispersal limitation, among other factors. In spite of this, studies aiming to quantify seed rain and test methods to enhance it, such as artificial perches, are still underrepresented in the Mediterranean. In our study, we quantified seed rain density and richness and tested the effects of artificial perches on such rain over a distance gradient on seven Mediterranean island old fields. In each of the seven sites, we positioned three sampling stations, each consisting of 1 seed trap under an artificial perch and 1 as a control…

Litter contribution to soil organic carbon in the agriculture abandons processes

Abstract. Mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in ecosystem functioning as it regulates the cycle of soil organic matter (SOM), CO2 emission into the atmosphere, carbon sequestration into the soil. In this study, it was investigated the contribution of litters of different stages of Mediterranean secondary succession on Carbon sequestration, analyzing the role of earthworms on translocation of SOM into soil profile. For this purpose δ13C difference between meadow C4-Csoil and C3-Clitter were used in a field experiment. Four undisturbed litters of different stages of succession were collected (45, 70, 100 and 120 since…

The impact of Pinus halepensis mill. afforestation on mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

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…

Impact of woody encroachment on soil organic carbon and nitrogen in abandoned agricultural lands along a rainfall gradient in Italy

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 pa…

Afforestation and reforestation: the Sicilian case study

In some regions of the world such as the Northern Hemisphere, the abandonment of agricultural land is one of the most widespread forms of land use change. In general, abandonment is followed by colonization by herbaceous and woody plants. Since the 1950s, wide areas of Southern Italy have been afforested for soil conservation improvement. In order to quantify the effects of agricultural abandonment and artificial afforestation on soil organic carbon (SOC), a dataset of 48 Sicilian sites has been analyzed. Because of their high environmental variability, these sites can be considered as representative of Southern Italy and in general of the Mediterranean basin. Soil samples were taken throug…

Dynamics of soil organic carbon pools after agricultural abandonment

Abandonment of agricultural land and the subsequent recolonization by natural vegetation is known to cause increases in C contents, contributing to reduction in atmospheric CO2 concentrations. Assessment of the possible mitigation of CO2 excess requires understanding the SOC dynamics, the origin of C pools and the pathways of their transformation. The aims of this work were to assess, by using the δ13C signature, the changes of old and new organic C in total (soil organic carbon, SOC) and labile (microbial biomass C, MBC, dissolved organic C, DOC, CO2 efflux from soil) pools after vegetation change from vineyard (C3) to grassland (C4) under semiarid Mediterranean climate. Colonization of ab…

Carbon dynamics of soil organic matter in bulk soil and aggregate fraction during secondary succession in a Mediterranean environment.

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 si…

A fuzzy multi-criteria decision-making methodology to optimise olive agro-engineering processes based on geo-spatial technologies

In southern Italy, the olive oil sector is an important part of the primary sector and its development requires support from research to ensure its sustainability. This work proposes the first step for set up a decision support system (DSS) for establishing mechanisation in agricultural operations for different olive groves. To contribute to this goal researches have been carried out to test the ability of remote sensing (RS) and geographic information system (GIS) to map olive groves and their agronomic characteristics. In detail, this study aimed to classify olives grove areas in terms of agronomic suitability and detect horticultural characteristics of olive groves in order to develop a …

Carbon stock increases up to old growth forest along a secondary succession in Mediterranean island ecosystems.

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 undec…

Litter contribution to soil organic carbon in the processes of agriculture abandon

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 colle…

Il ruolo degli uccelli come vettori di dispersione durante le successioni secondarie

Grassland fire effect on soil organic carbon reservoirs in a semiarid environment

Abstract. 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 affecte…

Additional insights on the ecology of the relic tree Zelkova sicula di Pasquale, Garfì et Quézel (Ulmaceae) after the finding of a new population

Abstract In early autumn 2009 a new population of Zelkova sicula, a very threatened tree species endemic to Sicily, has been found some 17 km east from the first and unique population previously known. The abiotic (slope, rock and stone outcrop cover, environmental stress, etc.) and biotic (plant species composition, vegetation mean height, total cover, etc.) features of 30 plots selected within the two populations were investigated in order to contribute at clarifying the actual and potential eco-geographic range of this species. Data analysis showed that the floristic differences among the sampled plots mostly relate to the rather high micro-habitat amplitude of the target species and the…

Biodiversity of the Sicilian Forests. Part I: the birds

E stata censita la diversita delle specie ornitiche presente in alcune tipologie forestali della Regione Siciliana e la relazione tra le ornitocenosi, le scelte gestionali ed i diversi fattori abiotici e biotici. L’analisi della species richness (= numero delle specie) dimostra che essa e correlata con il bioclima, il diametro massimo degli individui arborei, il valore trofico di tutti gli strati di vegetazione ed il valore trofico dello strato arboreo. I boschi meso-supramediterranei sono piu ricchi di specie rispetto ai boschi termomesomediterranei. L’importanza del diametro massimo degli individui arborei, che esprime indirettamente anche il tipo di gestione di un bosco, viene spiegata d…

The effects of post-pasture woody plant colonization on soil and aboveground litter carbon and nitrogen along a bioclimatic transect.

Abstract: 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 …

Automatic detection and agronomic characterization of olive groves using high-resolution imagery and LIDAR data

The Common Agricultural Policy of the European Union grants subsidies for olive production. Areas of intensified olive farming will be of major importance for the increasing demand for oil production of the next decades, and countries with a high ratio of intensively and super-intensively managed olive groves will be more competitive than others, since they are able to reduce production costs. It can be estimated that about 25-40% of the Sicilian oliviculture must be defined as “marginal”. Modern olive cultivation systems, which permit the mechanization of pruning and harvest operations, are limited. Agronomists, landscape planners, policy decision-makers and other professionals have a grow…

La biodiversità dei boschi siciliani. Parte I: l’avifauna

È stata censita la diversità delle specie ornitiche presente in alcune tipologie forestali della Regione Siciliana e la relazione tra le ornitocenosi, le scelte gestionali ed i diversi fattori abiotici e biotici. L’analisi della species richness (= numero delle specie) dimostra che essa è correlata con il bioclima, il diametro massimo degli individui arborei, il valore trofico di tutti gli strati di vegetazione ed il valore trofico dello strato arboreo. I boschi meso-supramediterranei sono più ricchi di specie rispetto ai boschi termomesomediterranei. L’importanza del diametro massimo degli individui arborei, che esprime indirettamente anche il tipo di gestione di un bosco, viene spiegata d…

Grassland fire effect on soil organic carbon reservoirs in semiarid environment

Abstract. The aim of this work was to investigate the effect of a experimental fire, used for grassland management, on soil organic carbon (SOC) reservoirs. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand and Schinz (Am) grasslands, located in the north of Sicily. Soil samples were collected at 0–5 cm before and after experimental fire and SOC was measured. During grassland fire soil surface temperature was monitored. Biomass of both grasses was analyzed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation cover, while it is not affected in the …

An empirical test of neighbourhood effect and safe-site effect in abandoned Mediterranean vineyards

The importance of both neighbourhood effect and safe-site effect for the colonization of Mediterranean old fields by woody plants was investigated. Using a transect approach, we recorded colonization of 21 species of woody plants on abandoned, terraced vineyards on Pantelleria Island (Sicily) in dependence from neighbouring terraces in older succession stages (Maquis) and available safe sites for seedling establishment (former crop plant, terrace wall). With a paired design of four treatments, including presence/absence of adjacent older successional stages, and North-/South-facing slopes, a neighbourhood effect could be shown for both expositions if the transect started from an adjacent fi…

Inventario dei paesaggi a terrazze in Sicilia

Olive agroforestry systems in Sicily: Cultivated typologies and secondary succession processes after abandonment

The first part of this study provides an overview on Sicilian olive systems. Subsequently, the study describes the different typologies of cultivated agroforestry systems present in South-Eastern Sicily employing olive trees in association with other Mediterranean tree species, in particular for the production of firewood, coal and animal food (downy or pubescent oak, holm oak, cork oak), but also in association with forage or grazing species (oat, barley, vetch, etc.) or cereals. The study shows that Sicilian agroforestry systems are much more diversified than it was known so far. In the second part, the study describes the spontaneous colonization processes by plants, observed in abandone…

Dal coltivo ai boschi vetusti in ambienti mediterranei: l’accumulo di carbonio e azoto in suolo e lettiera durante i primi 120 anni dall’abbandono.

Soil carbon dynamics during secondary succession in a semi-arid Mediterranean environment

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 (S…