Search results for "SUCCESSION"

Impact of wheat straw decomposition on successional patterns of soil microbial community structure

2009

International audience; The dynamics of indigenous bacterial and fungal soil communities were followed throughout the decomposition of wheat straw residue. More precisely, such dynamics were investigated in the different soil zones under the influence of decomposing wheat straw residue (i.e. residues, soil adjacent to residue = detritusphere, and bulk soil). The genetic structures of bacterial and fungal communities were compared throughout the decomposition process long by applying B- and F-ARISA (for bacterial and fungal-automated ribosomal intergenic spacer analysis) to DNA extracts from these different zones. Residue decomposition induced significant changes in bacterial and fungal comm…

Analisi dei processi di rinaturalizzazione nei vigneti e cappereti abbandonati del paesaggio terrazzato di Pantelleria (Canale di Sicilia)

2004

This study analyses the vegetation dynamics in the terrace landscape of Pantelleria Island (Sicilian Channel). The main questions were to determine the sequence of plant communities in time and to find out which environmental factors influence the course and the speed of succession. In the thermomediterranean part of the island were made vegetation relevés in five different fallow age classes, investigating three different ecological subunits: the terrace surface, the wall base and the wall in North-facing as well as in South-facing vine and caper fallows. The results show that undisturbed abandoned terraces are subject to rapid renaturation: 50 to 80 years old fallows are covered by dense …

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

2018

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…

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

2013

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…

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

2015

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…

The effects of land abandonment and long-term afforestation practices on the organic carbon stock and lignin content of Mediterranean humid mountain …

2019

Afforestation is an important strategy that can decrease atmospheric carbon by sequestering carbon in biomass and soil. In Spain, an active afforestation programme was adopted in the 1950s when the soil was severely eroded after widespread abandonment of arable land. The Araguás catchment (Central Spanish Pyrenees) is a good example of this programme because it was afforested with both Pinus sylvestris L. (PS) and Pinus nigra J.F.Arnold (PN). The soil organic carbon (SOC) stock and lignin content (based on the vanillyl, syringyl and cinnamyl contents) of these afforested soils were examined and compared to those of bare soil, secondary succession and meadow soils. Both the SOC stock and lig…

Middle Eocene calcareous nannofossils in the Jaca transect (South-central Pyrenees Eocene Basin, Aragón river valley, Huesca)

2020

The calcareous nanoplankton is studied from the base of the turbidite systems of the Upper Hecho Group (Jaca Basin, middle Eocene of the South-central Pyrenean Basin) up to the Gracionepel instabilities, within the Larres slope Marls. This new chronostratigraphic contribution is of crucial importance for the improvement of the detailed temporal and spatial correlation framework of the genetically related depositional systems at basin scale. The calcareous nanofossil assemblage is largely dominated by Coccolithus pelagicus , C. formous as well as different species of Reticulofenestra , accompanied by occasional specimens of several species of Sphenolithus  and Chiasmolithus . The results obt…

Succession et remplacements de communautés à brachiopodes en régime de sédimentation discontinue (Jurassique Moyen, Bourgogne, France)

1993

Abstract Sequence stratigraphy throws a new and seminal light on the fossil record and helps in determining the respective role played by external control (community replacement) and internal control (paleoecological succession) in the temporal “train” of marine benthic paleocommunities. Five brachiopod-dominated communities (C1–C5) are recognized and their temporal “train” described, during the uppermost Bathonian-lower Callovian interval in Burgundy. The first series (C1–C3) exhibits a trend interpreted as a paleoecological succession and the next two (C3–C4, C4–C5) as community replacements. Within the scope of sequence stratigraphy, the paleoecological succession comes at the end of a t…

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.

2013

Analisi degli approcci scientifici per la definizione comune di rinnovazione naturale con particolare riferimento all'ambiente mediterraneo

2015

La rinnovazione forestale è il futuro di ogni foresta ed è legata a diversi fenomeni ecologici. Molti studi hanno utilizzato vari metodi per analizzare la rinnovazione forestale; tuttavia, a livello internazionale, non esiste un metodo comune condiviso per classificare il fenomeno della rigenerazione stessa. Con l’obiettivo di trovare una possibile sintesi comune questo lavoro analizza il fenomeno della rinnovazione naturale attraverso sia l’analisi di inventari forestali sia di pubblicazioni scientifiche. La ricerca ha permesso di elaborare un elenco bibliografico multilingue attraverso l’interrogazione di database on-line, la ricerca con parole chiave e l’analisi dei riferimenti bibliogra…