Search results for " Quercus ilex"
showing 10 items of 11 documents
Conservation of genetic diversity in artificially regenerated holm oak (Quercus ilex L.) populations
2004
Reforestation with autochtonous species should take into account the preservation of the variability and the geographical structure of genetic diversity in forest species. In order to provide empirical data, genetic composition of an artificial population of holm oak (Quercus ilex L.) and its natural seed-origin population in Andalusia were analysed with six microsatellite loci. The genetic diversity indices applied show a reduction in the artificial stand if compared with the natural one, probably due to an inappropriate forester seed collection strategy limited to a few trees.
Preliminary observations on fungal endophytic community and mycorrhizal status in symptomless Quercus ilex seedlings
2014
Recently, a study on the Quercus ilex L. decay caused by biotic and abiotic agents has hypothesized alterations on endophytic and mycorrhizal fungal populations. Since holm oak is among the most representative Mediterranean species, that occurs widely in both urban and rural areas, in this work we preliminarly report these symbiotic fungal communities in asymptomatic seedlings, in order to compare these populations with those found in seedlings subjected to water and saline stress. Endophytic fungi were isolated from twigs and leaves and identified by morphological and molecular analysis. The ectomycorrhizal status was evaluated on root samples randomly selected to calculate the percentage …
Holocene environmental and climatic changes at Gorgo Basso, a coastal lake in southern Sicily, Italy
2009
Abstract We used a new sedimentary record to reconstruct the Holocene vegetation and fire history of Gorgo Basso, a coastal lake in south-western Sicily (Italy). Pollen and charcoal data suggest a fire-prone open grassland near the site until ca 10,000 cal yr BP (8050 cal BC), when Pistacia shrubland expanded and fire activity declined, probably in response to increased moisture availability. Evergreen Olea europaea woods expanded ca 8400 to decline abruptly at 8200 cal yr BP, when climatic conditions became drier at other sites in the Mediterranean region. Around 7000 cal yr BP evergreen broadleaved forests ( Quercus ilex , Quercus suber and O. europaea ) expanded at the cost of open commu…
A chronosequence study of vegetation dynamics on vine and caper terraces of Pantelleria Island (Sicily)
2006
The vegetation of fallow fields of different age in the terraced agricultural landscape of Pantelleria Island (Sicily) was analysed via vegetation relevés. Five age classes in N-facing as well as in S-facing slopes of both vine and caper fallows were differentiated. The main questions were to determine the sequence of plant communities in time and to test some environmental factors for their influence on the course and the speed of succession. The results show that undisturbed abandoned terraces are subject to rapid renaturation: 50 to 80 years old fallows are now covered by dense maquis communities. Both N- and S-facing slopes seem to converge to a Quercus ilex woodland as the climax commu…
Carbon stock increases up to old growth forest along a secondary succession in Mediterranean island ecosystems.
2019
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…
Mid- and late-Holocene vegetation and fire history at Biviere di Gela, a coastal lake in southern Sicily, Italy
2009
The vegetation and fire history of few coastal sites has been investigated in the Mediterranean region so far. We present the first paleoecological reconstruction from coastal Sicily, the largest island in the Mediterranean Sea. We analysed pollen and charcoal in the sediments of Biviere di Gela, a lake (lagoon) on the south coast of Sicily. Our data suggest that the area became afforested after a marine transgression at ca. 7200 cal b.p. (5250 b.c.). Build-up of forest and shrublands took ca. 200–300 years, mainly with the deciduous trees Quercus, Ostrya and Fraxinus. Juniperus expanded ca. 6900 cal b.p. (4950 b.c.), but declined again 6600 cal b.p. (4650 b.c.). Afterwards, evergreen trees…
Primi dati sugli alberi monumentali di Pantelleria
2016
Poche o nulla sono le informazioni sugli alberi monumentali delle piccole isole che circondano la Sicilia. Ciò è dovuto innanzitutto alla rarità di alberi definibili monumentali, le piccole isole hanno subito infatti una trasformazione ancora più profonda della Sicilia, ma anche ad un difetto di conoscenza. Il nostro vuole essere un primo contributo alla conoscenza degli alberi monumentali nell’isola di Pantelleria. Gli alberi censiti appartengono a due specie, il pino marittimo (Pinus pinaster subsp. hamiltonii) e il leccio (Quercus ilex). In realtà nel caso del pino marittimo possiamo parlare di un “popolamento monumentale” corrispondente alla pineta a pino marittimo presso la località Mo…
Living and Dead Aboveground Biomass in Mediterranean Forests: Evidence of Old-Growth Traits in a Quercus pubescens Willd. s.l. Stand
2017
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…
Vegetation dynamics on abandoned terraces of Sicily: the course and driving forces of succession
2007
In Mediterranean Europe, terrace landscapes can be found where 1) the orography is characterized by hills or mountains, 2) there is a high amount of stone outcrops and 3) the human need for agricultural production was quite high till the recent past. During the last century, many of these landscapes have been abandoned, due to their unsuitability for mechanized, intensive agriculture and due to the general land abandonment trend which arised in large parts of Europe. Since with land abandonment start secondary succession processes, the plant and animal communities linked to agroecosystems are replaced by other species which find their habitat in the developing succession stages. This proces…
1200-yr high-resolution terrestrial climate archive from the middle of the Mediterranean: The sedimentary record from Lake “Specchio di Venere” on Pa…
2011
The special location of Lake "Specchio di Venere" on Pantelleria Island in the Sicily Channel (Mediterranean Sea) between Tunisia and Sicily offers a unique terrestrial archive recording atmospheric changes, which are otherwise difficult to decipher in the marine records from this area. The lake is an endorheic saline basin with a maximum depth of 12.5 m. As the water input depends on rainfall, precipitation variations influence changes of the lake's water chemistry. In summer 2008, Lake Venere was cored with a modified Livingstone corer revealing a composite sedimentary sequence of 10.29 m length. Two radiocarbon dates form a preliminary age model indicating a very high sedimentation rate …