Emilio Badalamenti

Agricultural land abandonment in Mediterranean environment provides ecosystem services via soil carbon sequestration

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.

The impact of Carpobrotus cfr. acinaciformis (L.) L. Bolus on soil nutrients, microbial communities structure and native plant communities in Mediterranean ecosystems

Background and aims Carpobrotus spp. are amongst the most impactful and widespread plant invaders of Mediterranean habitats. Despite the negative ecological impacts on soil and vegetation that have been documented, information is still limited about the effect by Carpobrotus on soil microbial communities. We aimed to assess the changes in the floristic, soil and microbial parameters following the invasion by Carpobrotus cfr. acinaciformis within an insular Mediterranean ecosystem.

Arbuscular mycorrhizal fungi positively affect growth of Ailanthus altissima (Mill.) Swingle seedlings and show a strong association with this invasive species in Mediterranean woodlands.

Abstract Arbuscular mycorrhizal fungi (AMF) may promote plant invasion by enhancing plant performance and competitiveness. However, only a small number of studies have considered the interactions between local soil microbial communities and invasive plants, and even fewer have focused on alien trees. Ailanthus altissima (Mill.) Swingle is a serious problem in the Mediterranean Basin, where it has invaded many habitats. We investigated the symbiosis between A. altissima and indigenous AMF in two invaded, ecologically different Mediterranean woodlands. Mycorrhizal infection was high at both sites (> 60% of the root fragments were mycorrhizal), indicating that A. altissima roots may be infected by AMF under different ecological conditions. In a greenhouse experiment, A. altissima seedling growth was evaluated in untreated soil (natural soil containing the entire microbial community except AMF propagules), in sterilized soil, and in sterilized soil containing the entire microbial community except AMF. Seedling growth was greater in the natural soil than in the other two soils. Seedlings in natural soil but not in the other two soils were extensively colonized by AMF, indicating that AMF may have been responsible for the greater growth in the natural soil. Growth was poorer in the sterile soil that had been inoculated with a soil suspension lacking AMF propagules than in the sterile soil, suggesting that the natural soil also contained pathogens and that the AMF countered the effects of these pathogens. Overall, the results indicate that AMF are an important biotic component of Mediterranean woodlands invaded by A. altissima and AMF may facilitate A. altissimas invasion in these woodlands.

The alien vascular flora of Linosa (Pelagie Islands, Strait of Sicily): update and management proposals

Abstract: This paper provides an up-to-date overview of the naturalized alien plants of Linosa (Pelagie Archipelago, Sicily), which includes 83 taxa and accounts for 29 % of the total islands flora. Among these plants, 6 are invasive, 49 are naturalized and 28 are casual. With respect to previous available data, our field investigations resulted in the addition of 31 new xenophytes (21 casual and 10 fully naturalized). One of these species is new to the whole European territory (Kleinia anteuphorbia), 6 of them are new to Sicily and 11 are recorded for the first time on circum-Sicilian islets. For each alien plant, we indicate the habitat where the naturalization has been observed by using the codes proposed by Natura 2000 and Corine Biotopes habitat classification. We also provide a list of 159 alien plants that are cultivated in Linosa, but currently not naturalized, in order to underline the key role played by horticulture and gardening in the introduction of exotic species. In order to address this phenomenon and its huge impact on the integrity of both the natural and the traditional rural landscape, several actions are proposed that aim at preventing, controlling and monitoring both the ongoing and the potential invasion processes. Citation: Pasta S., Ardenghi N. M. G., Badalamenti E., La Mantia T., Livreri Console S. & Parolo G. 2017: The alien vascular flora of Linosa (Pelagie Islands, Strait of Sicily): update and management proposals. — Willdenowia 47: 135–144. doi: https://doi.org/10.3372/wi.47.47205 Version of record first published online on 13 July 2017 ahead of inclusion in August 2017 issue.

Seasonal effects on mortality rates and resprouting of stems treated with glyphosate in the invasive tree of heaven (Ailanthus altissima (Mill.) Swingle)

Tree of heaven (Ailanthus altissima) is regarded as invasive within urban and natural areas worldwide. Efficient methods to control it are significantly needed if we are to limit its well-known environmental and economic impacts. Up to now the use of herbicides has proven necessary since following mechanical damage, Ailanthus vigorously resprouts. However, the seasonal response of Ailanthus stems, treated with herbicides, has never been assessed. We compared the control efficacy recorded in autumn, winter and summer in an abandoned suburban citrus grove in Sicily, under Mediterranean-climate conditions. Glyphosate was injected within drill holes made in knee-high cut trees. Tree mortality and the resprouting ability of treated stems were significantly affected by the application timing and by diameter class of stems. Mortality was significantly lower in winter treatments within the smaller diameter class. Within the larger diameter class, only autumn treatments showed a notably higher mortality rate and a significantly lower growth of sprouts. Hence, autumn interventions are strongly recommended to effectively treat Ailanthus. Mortality was notably higher in the smaller diameter class. Our results confirm the importance of early intervention to control Ailanthus, also showing that the choice of the season is crucial to obtaining satisfactory control of its resprouting ability.

Nicodemia madagascariensis (Lam.) R. Parker (Family Scrophulariaceae), a casual alien plant new to Italy

In this note the authors report the first case of naturalization of the Malagasy smoke bush within Italian territory. Along with a description of the abiotic and biotic characteristics of the invaded site, the current demographic and dynamic trends of the detected population by means of growth-ring analysis was also assessed. Moreover, an overview on the history of its introduction in Europe is provided, underlining the key role played by the Mediterranean cities with respect to the acclimatization and spread of alien tropical and subtropical plants. Due to its low frequency under cultivation, the Malagasy smoke bush should not behave as an invader in the future; on the other hand, its ability to cover and smother neighbouring trees in very short times, make its spread within the whole Mediterranean area worth regular monitoring.