1,720,996 research outputs found
Found but lost? The short-lived success of <i>Crataegus coccinea</i> L. (Rosales: Rosaceae) in north-eastern Sicily (Italy)
Full text linkTwo exsiccata sampled at the end of the 19th century, and wrongly identified as Pyrus torminalis or Sorbus torminalis in the herbarium of Francesco Tornabene at Catania, belonged to a woody species never reported to occur in Sicily, Crataegus coccinea. This hawthorn, native to eastern North America, grew in two different sites located on the foothills of Mt. Etna. These records are of interest because they represent the first and only ones concerning the occurrence of this species outside botanic gardens in southern Europe. Never observed by the botanists who explored Sicily over the following 130 years, C. coccinea has probably experienced a short period of success as an ornamental plant cultivated in public and private gardens. The available information does not allow us to establish with certainty whether this species was fully naturalised in the Etnean territory in the past or not. C. coccinea should therefore be regarded as a dubious alien plant for Sicily. In the following decades this hawthorn was unable to become established, probably because of the severe constraints of fully Mediterranean climatic conditions
Additional data on the ongoing naturalization of the non-native woody plant Duranta erecta (Verbenaceae) in Sicily, Italy
Full text linkWe recorded the occurrence of Duranta erecta L. in the Aeolian Islands (Sicily, Italy), where it currently behaves as a casual alien. At the global scale, however, this woody species has shown highly invasive behaviour in different island ecosystems. On the basis of this evidence, we have investigated which ecological and biological traits may have allowed its establishment and spread, and could trigger its further expansion in the Aeolian Islands in the near future. Several factors seem to have favoured its success on a global scale, such as the wide edaphic and climatic range, the tolerance to anthropogenic disturbance, and the production of toxic metabolites that protect it from herbivore browsing and from competition with other plants. The study of the organisms that perform pollination and seed dispersal is probably the key to understanding the local naturalization of this plant, introduced about three centuries ago in Europe and the Mediterranean, here discussed in detail for the first time
High diversity of root endophytes in the pioneer endemic Betula aetnensis Raf. colonizing volcanic lavas
No full textIntroduction 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 collected in its natural habitat (NAT, NE slopes of Etna volcano, Sicily) and in a forest nursery (NURS). Plant age was determined and soil analysis were carried out to measure soil pH, organic matter, C, N, and P content. Root tips were analyzed under the microscope for Ectomycorrhizal (EM) structures, and root fragments where stained and observed for arbuscular mycorrhizal (AM) and endophytic fungi. The automated ribosomal intergenic spacer analysis (ARISA) was performed to investigate the diversity of prokaryotic and eukaryotic root endophytes. Denaturing gradient gel electrophoresis (DGGE) was applied further to investigate the fungal diversity and endophytes were identified by sequencing of DGGE bands. Results Betula aetnensis root tips exhibited a high level of EM colonization (average 75% NAT, and 94% NURS) with clear morphological differences suggesting the occurrence of different fungal species. The typical AM structures were observed with high frequency of colonization (> 93%). Fungal endophytic structures were also observed. All the symbiotic structures were found in all NAT and NURS plants regardless the plant age and the higher OM content of the NURS soil. Bacterial diversity, investigated by ARISA, was higher than fungal diversity, and the endophytic fungal diversity was higher in NAT roots than in the NURS roots. Surprisingly, the typical ECM and AMF fungal sequences were not obtained by molecular analysis (DGGE) as most sequences were affiliated to Ascomycetes (mostly Helotiales) and Basidiomycetes. Helotiales, referred to as dark-septate endophytes (DSE) with an as yet undefined ecological role, appeared the dominant components of the fungal community inhabiting both NAT and NURS B. aetnensis roots. Conclusion This is the first report of the occurrence of a four-way symbiotic interaction in B. aetnensis. This complex co-occurrence of ECM, AMF and other endophytes in the same root system has rarely been observed. The results suggest that B. aetnensis finds in the harsh lava of the Etna volcano enough propagules to establish such complex multipartite interactions. The role played by these symbionts for B. aetnensis growth and survival is to be elucidated as they could be of key importance for the conservation of this endemic threatened species
Contrasting Influence of Vegetation, Landscape, and Abiotic Factors on Bat Activity Across Different Mediterranean Habitats
No full textMosaic landscapes are anticipated to hold a higher abundance and diversity of Mediterranean bat species.
However, the magnitude in which vegetation structure at local and landscape scales, the presence of livestock,
anthropogenic structures such as buildings and roads, and abiotic factors influence bat activity and richness
still need to be better investigated. Here, we used acoustic monitoring over two years to explore the seasonal
response of bat activity and species compositions across four different habitats (forest, shrubland, olive grove, and
pastureland) inside a natural reserve in Sicily, Italy, and understand the effects of vegetation structure, landscape
scales and abiotic factors on the bat activity and species richness. We identified a total of 15 bat species and
phonic groups from 10,957 calls. Pipistrellus kuhlii, Pipistrellus pipistrellus and Pipistrellus pygmaeus were the
most prevalent species. We found no significant variations in bat activity among the studied habitats. However,
overall, higher bat activity was associated with areas exhibiting trees with higher diameter at breast height (i.e.,
forest habitats). A negative correlation was noted between open and narrow bat guild species activity and road
proximity, while dung density positively influenced narrow bat activity. Abiotic factors, such as elevation and
moonlight illumination intensity, had a positive impact on overall bat activity. Our results reflect the significant
role of mosaic landscapes in shaping bat communities, influencing bat activity and species distribution while
providing diverse landscape and vegetation compositions that can support different bat species and guild groups
The Root Mycobiota of Betula aetnensis Raf., an Endemic Tree Species Colonizing the Lavas of Mt. Etna (Italy)
Full text linkBetula aetnensis is an endemic tree of high conservation value, which thrives on the nutrientpoor
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 (ERM) fungi, and dark septate endophytes (DSE). A high diversity of
the bacterial community was observed whilst the root fungal assemblage of NAT plants was richer
than that of NURS. Root and rhizosphere fungal communities from NAT plants were characterized by
Illumina MiSeq sequencing. Most of the identified sequences were affiliated to Helotiales, Pezizales,
and Malasseziales. Ascomycota and Basidiomycota dominated roots and rhizosphere but differed in
community structure and composition. ECM in the roots mainly belonged to Tylospora and Leccinum,
while Rhizopogon was abundant in the rhizosphere. The Helotiales, including ERM (mostly Oidiodendron)
and DSE (mostly Phialocephala), appeared the dominant component of the fungal community.
B. aetnensis harbors an extraordinarily wide array of root-associated soil microorganisms, which are
likely to be involved in the adaptation and resistance mechanisms to the extreme environmental
conditions in volcano Etna. We argue that nursery-produced seedlings could lack the necessary
microbiota for growth and development in natural conditions
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?
Full text linkWith 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 behaviour
Invasive non-native trees in Natura2000 sites of Sicily: relevance and management issues
No full textInvasive non-native trees (INNTs) are an ever-increasing component of natural and seminatural communities worldwide. However, for the high competitive ability of INNTs and their tendency to cover and dominate over large areas, such a trend is commonly associated with a reduction of biodiversity along with a simplification and banalization of ecosystems. These detrimental ecological effects are likely to impact more on protected sites, established with the main aim to preserve native ecosystems and species. In this general framework, we assessed the abundance and spread of the main INNTs occurring in the Special Areas of Conservation of Sicily, being part of the Natura2000 network and designed according to the Habitats Directive (92/43/EEC). In particular, we accessed the management plans of all SACs present in Sicily, that is about 200 protected sites. We selected the INNTs having a higher ability to invade natural and seminatural habitats in Sicily, including forest systems: Ailanthus altissima, Acacia saligna, Eucalyptus camaldulensis, Parkinsonia aculeata, Robinia pseudoacacia and Vachellia karroo. We also took into consideration the inclusion in the list of invasive alien species of Union concern pursuant to Regulation (EU) 1143/2014. Within the management plans, we found three main information types concerning INNTs: presence/absence, abundance level and invasiveness status. The results of the research will help to identify the most widespread INNTs as well as some patterns of tree invasion in Natura2000 sites of Sicily. Furthermore, we assessed whether well-known invasive tree species are adequately considered as serious threats in the management efforts addressed to biodiversity conservation in protected sites of Sicily
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The ecological role of Pyrus Spinosa Forssk. in the ecosystem recovery and land restoration of Mediterranean woodlands
No full textIn 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 pasturelands mixed with mantle vegetation dominated by shrub species of the Rosaceae family. We assessed the effect of pear individuals considering a paired-site approach and comparing each individual with nearby grassland vegetation patches. Particularly, we measured plant height, basal diameter and crown projections along with cardinal directions. We also compared pear individuals with a single trunk and stumps with coppice shoots (multistemmed) to assess the influence of tree structure on the studied parameters, as well as distinguishing pear plants occurring before or after 1992. Pyrus plants significantly increased soil fertility compared to grassland, with a higher effect of the single trunk than stumps, while plant age seemed to play a minor role. Conversely, a multi-stemmed tree structure may be beneficial for protecting juveniles woody plants from browsing damage. Our results suggest that Pyrus spinosa can represent an excellent species to significantly improve soil conditions and trigger the restoration of woodlands in Mediterranean areas
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