Solanum capsicastrum Schauer (Solanaceae) spontaneizzato nella piana di Palermo (Sicilia nord-occidentale)

Si riportano i primi casi di naturalizzazione nella piana di Palermo (Sicilia nord-occidentale) di Solanum capsicastrum Schauer, un piccolo arbusto di origine sudamericana della famiglia della Solanaceae.

Pine stand density influences the regeneration of Acacia saligna (Labill.) H.L.Wendl. and native woody species in a mediterranean coastal pine plantation

Mediterranean plantations are the most suitable areas to assess vegetation dynamics and competitive interactions between native and exotic woody species. Our research was carried out in a coastal pine plantation (Sicily) where renaturalization by native species (Pistacia lentiscus L. and Olea europaea var. sylvestris) and invasion by Acacia saligna (Labill.) H.L.Wendl. simultaneously occur. The regeneration pattern of woody species in the pine understory was evaluated in six experimental plots along a stand density gradient, from 200 to approximately 700 pines per hectare. Both pine stand density and regeneration by native species had a significant negative relationship with Acacia natural …

Tree invasions in Italian forests

Many forest tree species have been moved outside their native range to provide goods and services elsewhere, but some of them have become invasive, causing negative impacts on biodiversity and human activities. The assessment and knowledge on the degree and scale to which forest ecosystems are invaded by non-native trees is of paramount importance for tailored policies and strategies aiming at forest conservation. By analyzing main databases and literature and applying a four-level scale of invasion (not currently invaded and with low invasibility; potentially invasible; moderately invaded; massively invaded), we assessed the current and potential occurrence of twenty-five invasive non-nati…

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. Methods: Within three study areas a paired-site approach, comparing an invaded vs. a non-invaded plot, was established. Within each plot biodiversity indexes, C and N soil content, pH and microbial biomass and st…

Spatial variability of ecophysiological performances and invasive potential of alien acacias (Acacia spp.) in Sicily and Lampedusa island (Pelagie Archipelago)

Acacia spp. are among the most widespread and prominent invaders within Mediterranean-type ecosystems, where have already shown the capability to deeply change the characters and the functioning of invaded ecosystems (like in Portugal or S Africa: e.g. Holmes & Cowling, 1997; Hellmann et al., 2011). In Sicily, just in the last few years, two Australian Acacias, notably Acacia cylops A. Cunn. ex G. Don and A. saligna (Labill.) H.L.Wendl., started to regenerate abundantly within different areas (especially afforested sites). However their naturalization process has not been studied up to now.

The Root Mycobiota of Betula aetnensis Raf., an Endemic Tree Species Colonizing the Lavas of Mt. Etna (Italy)

Betula aetnensis is an endemic tree of high conservation value, which thrives on the nutrient-poor volcanic soils of Mount Etna. Since plant–microbe interactions could play a crucial role in plant growth, resource uptake, and resistance to abiotic stresses, we aimed to characterize the root and rhizosphere microbial communities. Individuals from natural habitat (NAT) and forest nursery (NURS) were surveyed through microscopy observations and molecular tools: bacterial and fungal automated ribosomal intergenic spacer analysis (ARISA), fungal denaturing gradient gel electrophoresis (DGGE). B. aetnensis was found to be simultaneously colonized by arbuscular (AM), ectomycorrhizal (ECM), ericoid…

Which are Southern Italy’s fastest growing tree species? Lessons from the past for future perspectives, with a special focus on Sicily

Fast growing tree species can generate high wood production in a short time frame. However, maximum productivity is dependent on environmental and management conditions as well as intrinsic plant traits. Within this framework, our research was into tree species with the highest Mean Annual Increments (MAIs) in southern Italy, particularly in Sicily. Eucalyptus spp., Acacia saligna (Labill.) H. L. Wendl., Ailanthus altissima Mill. (Swingle), Pinus halepensis Mill. (including Pinus brutia Ten.), Pinus canariensis C.Sm. and Pinus radiata D. Don. were identified. In particularly suitable conditions, the MAI of eucalypt coppices ranged from 8 to 12 m3 ha-1, and from 13 to 19 m3 ha-1, in Eucalypt…

The cork oak in the Mountains of Palermo (Italy): ecological insights from the south-eastern edge of its distribution range

Abstract: The uneven presence of the cork oak (Quercus suber L.) within its distribution range is not only determined by its climatic requirements but also by specific edaphic needs. Although most of the natural populations thrive in acidic soils deriving from metamorphic or volcanic rock outcrops, some cork oak populations are found growing in soils deriving from calcareous bedrock, which are considered less suitable. We carried out a multidisciplinary investigation at the south eastern edge of the Q. suber distribution range (Mountains of Palermo, NW Sicily), including soil, floristic, and vegetation surveys, aimed at: (i) assessing the native or introduced origin of some peculiar cork oa…

Recovery of cork forests and enhancement of by-products

Cork oak (Quercus suber L.) is a tree species native to the western Mediterranean Basin (EUFORGEN 2019). Cork oak forests are human-shaped ecosystems that have to be managed to be preserved in a long-term perspective. Cork oak stands range from closed forests to open woodlands, provide high ecosystem services, mainly through cork production, support high biodiversity and provide carbon storage and water regulation services. Due to their important ecological role, these ecosystems are listed in the European Habitats Directive (Habitat 9330: Quercus suber forests, EEC, 1992). In the last years, especially in Italy, cork oak stands are undergoing a relevant regression due to the decline of tra…

Risultati dell’indagine preliminare per l’individuazione dei boschi vetusti in Sicilia

La gran parte degli ecosistemi forestali del Mediterraneo è stata modificata ed utilizzata dall’uomo da millenni. I sistemi forestali più vicini alle condizioni di naturalità sono quelli non più gestiti e/o sottoposti ad un efficace regime di protezione e che tendono a recuperare caratteri strutturali e di funzionamento ecosistemico simili a quelli delle formazioni primarie originali. In Sicilia le conoscenze sulla presenza e diffusione dei boschi vetusti sono ad uno stadio preliminare. Nel più recente inventario forestale regionale è stata effettuata una prima selezione di 18 soprassuoli forestali considerati potenzialmente vetusti, che ricoprono 472 ettari di superficie. Sulla base dell’a…

Carbon storage of Mediterranean grasslands

Secondary grasslands are one of the most common vegetation types worldwide. In Europe, and in the Mediterranean basin, human activities have transformed many woodlands into secondary grasslands. Despite their recognized role in the global carbon cycle, very few data are available for estimating the biomass of Mediterranean grasslands. We developed linear regression models in order to predict the biomass of two native Mediterranean grasses (Ampelodesmos mauritanicus and Hyparrhenia hirta) and an invasive alien grass (Pennisetum setaceum). Ampelodesmos mauritanicus is very common throughout the Mediterranean basin, mostly on north-facing slopes, H. hirta characterizes thermo-xeric grasslands,…

The ongoing naturalisation of Eucalyptus spp. in the Mediterranean Basin: new threats to native species and habitats

The genus Eucalyptus has been widely introduced into many regions of the world outside its native range and has become invasive in some Mediterranean biomes (e.g. in southern Africa and California). In the Mediterranean Basin and Europe, eucalypts were introduced at the end of the 18th century. However, natural regeneration events in these regions are recent in time and limited in terms of affected areas, except for the Iberian Peninsula. An updated overview about the natural spread of Eucalyptus species in Italy is still lacking. This paper aims to fill this knowledge gap, using both published data and unpublished field data regarding naturalisation events, with a specific focus on Sicily.…

Primi casi di naturalizzazione del noce nero (Juglans nigra L.) (Juglandaceae) in Sicilia

Il presente studio riporta i primi casi di naturalizzazione del noce nero in Sicilia. Il possibile ruolo giocato dagli animali disseminatori e dalle condizioni climatiche locali sono stati discussi.

<i>Acacia cyclops</i> A. Cunn. ex G. Don (Leguminosae) in Italy: first cases of naturalization

The first two cases of naturalization of <i>Acacia cyclops</i> are reported for Italy. Young trees were observed growing in the wild some 15 years ago on Linosa (Pelagie Islands, Strait of Sicily). A decade later, this alien plant should no longer be considered as a casual, since a very intensive process of self-sown regeneration has been observed in some plantations on Lampedusa, the major island of the same Archipelago. The available literature suggests the need for careful monitoring of the ongoing invasion process, as <i>A. cyclops</i> has already shown a very invasive behaviour elsewhere within Mediterranean-type biomes due to its ability to withstand high envir…

First record of Heptapleurum arboricola Hayata (Araliaceae) as a casual non-native woody plant in the Mediterranean area

I report here the first record of Heptapleurum arboricola Hayata (syn. Schefflera arboricola (Hayata) Merr.) (Araliaceae) as a casual non-native plant throughout the Mediterranean area. I observed the natural regeneration in urban areas at Castellammare del Golfo, a small coastal town in north-west Sicily (Mediterranean Italy). Due to the lack of self-sustaining populations and the short-term observational period, Heptapleurum arboricola should be considered as a casual species according to the classification of non-native plants. The detection of early signs of naturalization of non-native plants is of crucial importance for the management and control of invasive species. The main abiotic …

High diversity of root endophytes in the pioneer endemic Betula aetnensis Raf. colonizing volcanic lavas

Introduction Betula aetnensis Raf. is an endemic tree species native to Sicily of particular conservation value, that establishes on nutrient-poor and water-limited lava of Etna volcano. In these harsh conditions plant-microbe interactions could play a crucial role in plant growth, resource uptake and resistance to abiotic stresses. The aim of this study is to investigate the root-associated microbial community of B. aetnensis growing in its natural habitat. The comparison between individuals from natural habitats and nursery-grown seedlings aims to assess the symbiotic status of plant material used for afforestation purposes. Materials and Methods Betula aetnensis individuals were collecte…

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 a…

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

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 island's 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…

Low mimosine content and nutrient-rich foliage of two Leucaena leucocephala varieties: a potential fodder resource in Mediterranean agroforestry systems

Leucaena leucocephala is worldwide used for wood production, reforestation and for feeding livestock. To assess the potential use of leucaena for animal nutrition, we analysed the composition of methanolic extracts of leaf samples of two varieties occurring in Sicily (Mediterranean area), also determining the presence of mimosine.

Primo caso di naturalizzazione di Pinus canariensis C. Sm.(Pinaceae) per la Sicilia e prima stazione di Acacia cyclops G. Don (Fabaceae) sull’isola maggiore

Nella Riserva Naturale Orientata “Foce del Fiume Platani” (Sicilia meridionale) sono stati registrati il primo caso di naturalizzazione di Pinus canariensis (Pinaceae) per il territorio regionale ed il primo di Acacia cyclops (Fabaceae) per l’isola maggiore. Vengono inoltre fornite informazioni supplementari sulla demografia e sulla distribuzione di entrambe le specie nei rimboschimenti dell’area protetta, nonché una previsione del loro grado di invasività alla luce dei dati scientifici già pubblicati. First case of naturalization of Pinus canariensis in Sicily and first population of Acacia cyclops on the main island. Both cases of naturalization have been recorded within the Nature Reserv…

Azioni di contenimento dei fenomeni erosivi, di salvaguardia e restauro degli habitat nell’ambito del Progetto LIFE “MACALIFE - Preservation and extension of priority habitats damaged from agriculture activity”: un modello per le zone aride della Sicilia

In Sicilia, come del resto in gran parte del Mediterraneo, l’impatto millenario delle attività antropiche ha profondamente modificato la struttura e la funzione degli ecosistemi naturali, con evidenti ripercussioni sulla stabilità dei suoli e sull’andamento diffuso dei processi erosivi. L’accresciuta consapevolezza di que-sto rapporto causa-effetto ha posto sempre più in risalto la necessità di mettere in atto adeguati interventi di recupero e di ripristino ambientale, in particolare a favo-re di ecosistemi più esposti e vulnerabili, perlopiù concentrati in corrispondenza delle aree costiere e umide, spesso profondamente trasformati a seguito dell'azione combinata di diversi tipi di disturb…

Shedding light on typical species: Implications for habitat monitoring

Habitat monitoring in Europe is regulated by Article 17 of the Habitats Directive, which suggests the use of typical species to assess habitat conservation status. Yet, the Directive uses the term “typical” species but does not provide a definition, either for its use in reporting or for its use in impact assessments. To address the issue, an online workshop was organized by the Italian Society for Vegetation Science (SISV) to shed light on the diversity of perspectives regarding the different concepts of typical species, and to discuss the possible implications for habitat monitoring. To this aim, we inquired 73 people with a very different degree of expertise in the field of veget…

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 abil…

The recent spread of the invasive woody alien plant Melia azedarach L. (Meliaceae) in Sicily

This paper aims at reporting the ongoing process of naturalization of Melia azedarach L. in Sicily. In fact, over half a century after the first detection of spontaneous self-sown seedlings, an abrupt increase of naturalization cases has been recorded by the authors during the last twenty years. More in detail, M. azedarach successfully colonized many suburban lowland areas along the coasts of the island which are characterised by thermo-Mediterranean bioclimate. According to both field and literature data, a gradual spread of M. azedarach in the island can be expected, although it is not possible to predict the speed with which this will occur. Historical information on its introduction at…

Handroanthus heptaphyllus (Bignoniaceae) in Sicily: a new casual alien to Italy and Europe

Handroanthus heptaphyllus (Bignoniaceae) is an ornamental tree native to different regions of South America (Brazil, Argentina, Bolivia, and Paraguay). Here we report from Sicily the first case of natural regeneration in Europe.

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 measur…

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…

Effects of Arbuscular Mycorrhizal Fungi on the Vegetative Vigor of Ailanthus altissima (Mill.) Swingle Seedlings under Sustained Pot Limitation

In order to invade new ecosystems, invasive alien plants need to cope with different microbial communities. Whilst the ability to avoid antagonists is well recognized, the opportunity to establish mutualistic associations is less known, even in widespread invasive species such as Ailanthus altissima (Mill.) Swingle. We sought to evaluate whether the beneficial effects of arbuscular mycorrhizal fungi (AMF) on Ailanthus seedlings are maintained over time, under prolonged pot limitation. We compared three-month-, three-year- and four-year-old mycorrhizal seedlings grown in natural forest soil (NT) with seedlings grown in sterilized (ST) and non-mycorrhizal (NM) soils, in pots of 3.4 L (22 &tim…

The use of species in plantations: renaturalisation and reforestation in Sicily

Afforestation and reforestation activities in Sicily have been widespread in the last century, in order to increase the forest cover that was seriously reduced in the former centuries. Notwithstanding this, Sicily is still characterized by only the 12% of the regional surface covered by woods and forest. The reforestation in the last century was carried out using conifers and eucalypts, just in order to ensure a quick protection of slopes and pastureland, coping diffuse erosion events, and those intervention had a remarkable success. Nowadays, the target of enlarging the forest areas in the island is still compulsive, but the use of species, considering the actual knowledge and nature consc…

The decline of the cork oak growing in Sicily is accompanied by the loss of the functions proper to agroforestry systems

The cork oak is one of the most important tree species in the Mediterranean basin, where it covers more than 2 million hectares. Among evergreen oaks, Quercus suber stands out for the variety of cultural systems in which it has been successfully employed, including typical agroforestry systems. Accordingly, a wide range of ecosystem services may be associated to cork oak, including the preservation of biodiversity, carbon sequestration and forage production. In the Mediterranean, the cork oak represents a key species for many natural and seminatural landscapes and habitats, as well as playing a prominent role for the economic and social development of local communities. However, there is in…

PLUMBAGO AURICULATA LAM. (Plumbaginaceae) IN SICILIA OCCIDENTALE: NUOVI DATI SULLA SUA DIFFUSIONE COME ESOTICA CASUALE

Plumbago auriculata Lam. (Plumbaginaceae) in western Sicily: new data on its spread as casual alien. In questa nota si fornisce un quadro aggiornato sui casi di naturalizzazione di Plumbago auriculata Lam. (Plumbaginaceae) nella Sicilia occidentale e sul suo status invasivo a livello nazionale ed internazionale. Questa xenofita viene segnalata per la prima volta in diverse aree delle province di Agrigento, Palermo e Trapani, dopo essere stata segnalata per la prima volta presso l'isola di Linosa, nell'arcipelago delle Pelagie.

Vegetation dynamics within afforested coastal areas: regeneration by native species or invasion by alien species?

During the last century, massive reforestation projects along the dunes of the southern Sicily have been carried out. Such interventions, far from being in line with the current trends of close-to-nature silviculture, are, however, particularly interesting to assess the vegetation dynamics in afforestation areas. Furthermore, these kind of interventions may determine two opposite effects, that is renaturalization by native woody species or invasion by alien species. Acacia spp. are among the most widespread and prominent invaders within Mediterranean-climate areas, where they have already shown the capability to deeply change the characters and the functioning of native ecosystems. For inst…

Stem-injection of herbicide for control of Ailanthus altissima (Mill.) Swingle: a practical source of power for drilling holes in stems

Abstract: 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 c…

Criteria to identify old-growth forests in the Mediterranean: A case study from Sicily based on a literature review and some management proposals

Old growth forests are increasingly considered and studied all around the world. However, the knowledge of such important forest systems is still limited in some bioclimatic regions, such as in the Mediterranean Basin. Starting from the knowledge acquired elsewhere, our research was carried out with the aim to select the most effective criteria to identify potential old-growth forests in Mediterranean ecosystems (Sicily, Italy). Four key proxy indicators were considered: deadwood amount, tree size, structural traits, and tree species richness. A preliminary classification of the local forest stands level in three classes of old-growthness (high, medium and low) has also been proposed. The m…

AILANTHUS ALTISSIMA (MILL.) SWINGLE (Simaroubaceae) IN SICILIA E CENNI STORICI SULLA SUA INTRODUZIONE IN ITALIA

Nonostante la diffusa presenza dell’ailanto in Sicilia, mancavano sino ad oggi studi specifici a carattere regionale su questa specie arborea esotica invasiva. Allo scopo di colmare alcune di queste lacune, il presente lavoro si è posto cinque obiettivi: 1) ripercorrere la storia della diffusione globale dell’ailanto, prestando particolare attenzione all’Italia ed alla Sicilia; 2) analizzare le cause (antropiche e biologiche) della sua spiccata invasività a livello globale e locale; 3) fornire un primo quadro della sua distribuzione e della sua auto- e sinecologia sul territorio regionale; 4) stabilire i metodi più idonei ed efficaci per contenerne la diffusione e ridurne l’impatto ecologic…

The ecological role of Pyrus Spinosa Forssk. in the ecosystem recovery and land restoration of Mediterranean woodlands

In the Mediterranean basin, large areas still call for active reforestation, having a very low woody cover, thus resulting less resistant and resilient to climate change and suffering from a higher risk of soil degradation processes. Knowing the effects on soil fertility and carbon sequestration of single woody species can be of great practical importance, although being rarely tested. We aimed to assess the effect of Pyrus spinosa on soil fertility (soil carbon and nitrogen), microbial biomass and carbon sequestration (in aboveground stems) of Mediterranean pasturelands. The research was carried out in Ficuzza Nature Reserve (NW Sicily), where large areas are composed of extensive pasturel…

Living and Dead Aboveground Biomass in Mediterranean Forests: Evidence of Old-Growth Traits in a Quercus pubescens Willd. s.l. Stand

For a long time, human impact has deeply simplified most of the forest ecosystems of the Mediterranean Basin. Here, forests have seldom had the chance to naturally develop a complex and multilayered structure, to host large and old trees and rich biological communities, approaching old-growth conditions. Also for this reason, limited information is currently available about Mediterranean old-growth forests, particularly with regard to deadwood. The main aim of this work is to help fill this critical knowledge gap. In Sicily (Italy), we identified a Quercus pubescens forest that seemed to show some typical old-growth features. Total living volume (360 m3 ha−1) and basal area (34 m2 ha−1) wer…

The Management of Invasive Non-Native Trees in the Mediterranean Protected Areas: Sicily as a Case Study

Invasive non-native trees (INNTs) are increasingly recognized to have negative effects on biodiversity and ecosystem services in protected areas. The management of INNTs is one of the major challenges to preserving native species and ecosystems, to which more and more efforts and resources are bound to be destined in the coming decades. Indeed, the combined effects of climate change and increasing disturbance factors (e.g. wildfires) are likely to aid the spread of many INNTs in the Mediterranean protected areas, as well as favouring their competitive relationships with native species. However, the effective implementation of control measures is far from being fully achieved. I assessed how…

Notes about the naturalization in Sicily of Paulownia tomentosa (Paulowniaceae) and remarks about its global spread

Paulownia tomentosa is native to different regions of East Asia. Here, the first case of natural regeneration in Sicily is reported. Although Paulownia is not still invading typically Mediterranean areas, mainly due to ecological constraints, its recognized invasiveness at a global level imposes the need to monitor the ongoing process.

The naturalization of the almond Prunus dulcis in different ecological contexts in the Mediterranean: An underestimated process?

Although Prunus dulcis has been frequently listed in non-native floras all around the world, its naturalization has been rarely studied in the field. Probably, because this species has generally invaded synanthropic habitats. We assessed the density of natural regeneration of almond, biometric parameters (height and basal stem diameter), and the distribution in life stage classes in three different ecological contexts in Sicily (Mediterranean Italy): one natural habitat (maquis), one pine afforestation and two prickly pear orchards. We recorded 236 naturally regenerating almond individuals, with density ranging from 140 individuals per hectare (prickly pear orchard 1) up to 2,400 individual…

Relationship between recruitment and mother plant vitality in the alien species Acacia cyclops A. Cunn. ex G. Don

Acacia cyclops is a widespread invader in Mediterranean-climate regions. However, although its naturalization in the Mediterranean Basin dates back only a few years ago, and the invasion process has not been studied hitherto. We investigated seedlings recruitment strategy adopted by A. cyclops in a small island (Lampedusa, Italy) where its natural regeneration was strictly confined under mother plants canopy. Healthy plants (DCP), plants at incipient senescence (SCP) and dead plants (DP) were distinguished according to vitality and canopy status. Living plants were also characterized in relation to leaf C and N isotope composition. Regeneration pattern (seedlings and saplings abundance) was…

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

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 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 …

Seedling growth of a native ( Ampelodesmos mauritanicus ) and an exotic ( Pennisetum setaceum ) grass

Scarce information is available on the biological reasons why a small subset of introduced species can effectively establish within novel ecosystems. A comparison of early growth traits can help to explain the better performance of alien invasive species versus native co-occurring species. In one year-long experiment, we compared the early life stages of Ampelodesmos mauritanicus (Poir.) Dur. & Schinz (Amp), a native perennial Mediterranean grass, and Pennisetum setaceum (Forssk.) Chiov (Penn), an emerging invader grass in sub-arid and Mediterranean-climate areas. The Penn seedlings grew significantly faster and were approximately 2.5 times taller than the Amp seedlings, reaching a fina…

The evolution in time of the concept of fast growing tree species: is it possible to use a definition applicable to all environmental conditions?

Although the expression “fast-growing species” (FGS) referred to tree species has been since long time used, a clear definition has not been adopted for decades. Starting from the Italian historical background, we searched for the definitions of FGS formulated over time at a national and international level. The mean annual increment (MAI) of 10 m3 ha-1, identified by the FAO, has been the most commonly considered threshold until recently. Subsequently, experimental activities and research efforts have consistently enhanced the productivity of FGS, and other definitions have been proposed accordingly. Hence, FGS should provide annual wood yields of 15-25 m3 ha-1 with rotations of less than …

Tempi e modi di un’invasione incontrastata: Pennisetum setaceum (Forssk.) Chiov. (Poaceae) in Sicilia.

Circa 50 anni fa venivano segnalati a Catania e a Palermo i primi due casi di spontaneizza-zione di Pennisetum setaceum (Forssk.) Chiov. sul territorio siciliano. Dopo un breve periodo di latenza, questa pianta paleotropicale ha cominciato a diffondersi sempre più rapidamente, tanto che oggi l'adozione di scelte d'intervento assume carattere d'urgenza per via del pesante impatto che essa ha sia sulle comunità pre-forestali (macchie degradate e garighe) sia sulle praterie perenni e annue locali. Dopo aver fornito una panoramica sul comportamento di questa xeno-fita, viene analizzato il suo processo di espansione in Sicilia e viene comparata l'ampiezza della sua nicchia ecologica con quella d…

Le specie alloctone invasive in Sicilia: caratterizzazione del fenomeno, strategie di colonizzazione e possibili strategie di contrasto

Acacia cyclops A. Cunn. ex G. Don (Leguminosae) in Italy: first cases of naturalization

The first two cases of naturalization of Acacia cyclops are reported for Italy. Young trees were observed growing in the wild some 15 years ago on Linosa (Pelagie Islands, Strait of Sicily). A decade later, this alien plant should no longer be considered as a casual, since a very intensive process of self-sown regeneration has been observed in some plantations on Lampedusa, the major island of the same Archipelago. The available literature suggests the need for careful monitoring of the ongoing invasion process, as A. cyclops has already shown a very invasive behaviour elsewhere within Mediterranean-type biomes due to its ability to withstand high environmental stresses. As migrating birds …

UN CASO SINGOLARE DI CRESCITA DI KALANCHOË DAIGREMONTIANA RAYM.-HAMET & H. PERRIER (Crassulaceae) SU PLUMERIA RUBRA L. (Apocynaceae)

Si riporta un caso singolare di crescita di Kalanchoë daigremontiana Raym.-Hamet & H. Perrier (Crassulaceae) su Plumeria rubra L. (Apocynaceae).

A casual alien plant new to Mediterranean Europe: Ceiba speciosa (Malvaceae) in the suburban area of Palermo (NW Sicily, Italy)

The abiotic and biotic characteristics of the first sites where floss silk tree behaves as a casual alien plant in the Mediterranean Europe are described. The species was probably first planted in botanical gardens of southern France few decades before mid XIX century. It was introduced in Palermo in 1896, a city which appears to match very well its climatic requirements. According to the available information on its biology and ecology in both its original and secondary range, the floss silk tree should not become an invasive alien plant in the Mediterranean. Nevertheless, several gaps need to be filled in order to increase our understanding of future trends of Ceiba speciosa in southern E…

È possibile tracciare un bilancio sull’eucalitticoltura in Sicilia e sulle sue prospettive?

La storia dell’eucalitticoltura in Sicilia è ormai una storia di mezzo secolo. La diffusione dell’eucalitticoltura in Sicilia e nelle regioni meridionali in genere ha corrisposto alla diffusione di un modello nuovo per queste realtà. Diversi errori sono stati compiuti soprattutto con riferimento alle scelte tecniche compiute a posteriori (scelta delle stazioni, assenza di cure colturali, utilizzazioni improprie). Un rinnovato interesse per questi popolamenti è derivato dalle opportunità offerte per l’utilizzazione energetica. Tuttavia anche questo approccio mostra i suoi limiti legati alla necessità di ricorrere a grossi volumi di legname e ad un utilizzo delle risorse legnose forestali sic…

The paradox of the alien plant Leucaena leucocephala subsp. glabrata (Rose) S. Zárate in Sicily: another threat for the native flora or a valuable resource?

With this contribution, an updated picture of the rapid expansion of Leucaena leucocephala subsp. glabrata in Sicily is provided. On the one hand, this is a quite worrying sign, as this woody species figures among the world’s worst invasive alien species. On the other hand, the species shows interesting potential for production purposes (for wood, biomass and for feeding livestock), also considering its nitrogen fixation ability. Consequently, the two opposite options to cope with this species, i.e. cultivation and control/eradication, should accurately take into account the possible uses as well as its invasive behaviou.