1,721,049 research outputs found
A network for monitoring terrestrial ecosystems along a latitudinal gradient in Continental Antarctica.
No full textA network for monitoring change in the vegetation communities to assess the impact of future
climate changes was established in Victoria Land (Continental Antarctica) in 2002 and 2003. The network is
within the framework of the SCAR project RiSCC (Regional Sensitivity to Climate Change in Antarctic
terrestrial and limnetic ecosystems), and in cooperation with LGP (Latitudinal Gradient Project) assessing
how ecosystem biodiversity and structure may change with latitude and with climate change. The network is
composed of 19 permanent plots at nine sites along a latitudinal gradient from Apostrophe Island (73°30'S,
167°50'E) to Granite Harbour (77°00'S, 162°26'E), with a main coastal transect and three subtransects inland
from the coast. The sites are representative of the most frequent environmental conditions and the most
widespread communities occurring in Continental Antarctica and in Victoria Land. The selected
communities show different ecological requirements and have different potential sensitivities to climate
change. The vegetation of each plot was described using the RiSCC research protocol, developed originally
in the Maritime Antarctic and here adapted, for plot size, to Continental Antarctica. This paper characterizes
the vegetation at the sites as the starting point of the long term monitoring
Moss and Lichen flora of Victoria Land (Continental Antarctica) along a Latitudinal Transect
No full textFlora and vegetation communities have been analysed in 24 sites, located
across a latitudinal gradient from 72° to 77°S, in Victoria Land (Continental Antarctica).
The study areas have been selected in different geographical, lithological and
environmental conditions, in order describe the flora and vegetation associated to the
widest range of ecological and environmental conditions occurring in Victoria Land. The
field surveys have been carried out following a research protocol developed within the
RiSCC Programme. Totally, 8 species of mosses, 50 of lichens have been observed in all
the study areas.
The obtained results indicate that, for what concerns the floristic composition and richness,
the latitudinal gradient does not seem to affect the species biodiversity, at least along the
coastal sites, with hot spots of biodiversity occurring along all the study transect. The
gradient from coast to inland seems to exert higher influence on the species types and
number and on the occurring vegetation communities. The data achieved, referred to the
phytosociological surveys and to the description of 20 permanet plots, will provide the
bases for the long term monitoring and the impact assessment of climate change effects as
well as of other significant environmental forces. In addition, these data will be useful to
evaluate eventual changes of the geographical distribution of some target species and/or of
changes of their ecological requirements and distribution patterns
Minimum area assessment and different sampling approaches for the study of vegetation communities in Antarctica
No full textAntarctic vegetation offers excellent opportunities for the study of dynamics and biodiversity of
natural systems with high environmental sensitivity. This paper addresses the methodological and technical
aspects for the minimum area (MA) assessment (the smallest area which adequately represents community
composition) and compares three different sampling approaches for vegetation at Jubany, King George
Island. Five target communities, among the most widespread and representative of a wide range of floristic
richness and dynamism, were selected through the phytosociological study. The minimum area, determined
from four methods, ranged between 2 and 24 m2. Similar values have been obtained for the polar desert
vegetation of the Northern Hemisphere. Three sampling approaches were tested in the five communities: the
phytosociological survey with 100 cm grid, the phytosociological survey with 5 cm grid, the point intercept
with 10 cm grid. To achieve comparable data a standard plot, satisfying the MA requirements of all the
communities, has been adopted for all the study sites. The results indicate that the integration of the three
methods provides the highest level of information , especially in respect of limitations on field sampling and
logistics
Vegetazione e dinamica dei rock glacier durante l’Olocene in Alta Valtellina (Italia)
No full textLa vegetazione di 7 rock glacier (di cui 5 attivi, 1 dubbio ed 1 inattivo) dell'Alta Valtellina (Italia) è stata analizzata attraverso 463 rilievi fitosociologici per determinare le relazioni tra vegetazione e grado di attività. La vegetazione fornisce uno strumento supplementare rispetto alla geomorfologia per determinare il grado di attività ed effettuare confronti tra rock glacier. Attraverso la vegetazione è stato possibile individuare e descrivere, senza l'ausilio di misurazioni dirette (teodolite, aerofotogrammetria) l'esistenza di pattern del movimento superficiale all'interno di ciascuna forma. Questi pattern sono stati individuati utilizzando, rispettivamente, la distribuzione delle associazioni vegetali e di singole specie indicatrici di instabilità
The secret of success
No full textParts of Antarctica have experienced warming almost an order of magnitude greater than the global average over the past 50 years, with the Antarctic Peninsula ranking among the three fastest-warming
regions on Earth. Antarctic ecosystems have been affected by the
warming that has taken place. Perhaps the most notable impact has been a dramatic expansion of the two species of flowering plant that occur on the continent — Antarctic pearlwort and Antarctic hair gras
A permafrost warming in a cooling Antarctica?
No full textThe magnitude and even direction of recent Antarctic climate change is still debated because the paucity of long and complete instrumental data records. While along Antarctic Peninsula a strong warming coupled with large retreat of glaciers occurred, in continental Antarctica a cooling was recently detected. Here, the first existing permafrost data set longer than 10 years recorded in continental Antarctica is presented. Since 1997 summer ground surface temperature showed a strong warming trend (0.31°C per year) although the air temperature was almost stable. The summer ground surface temperature increase seemed to be influenced mainly by the increase of the total summer radiation as confirmed also by the
increase of the summer thawing degree days. In the same period the active layer exhibited a thickening trend (1 cm per year) comparable with the thickening rates observed in several Arctic locations where air warming occurred. At all the investigated depths permafrost
exhibited an increase of mean annual temperature of approximately 0.1°C per year. The dichotomy between active layer thickness and air temperature trends can produce large unexepected and unmodelled impacts on ecosystems and CO2 balance
Itinerari naturalistici al Passo dello Stelvio - Impatti del Cambiamento Climatico: passato, presente e sfide per il futuro
No full textIl libro tratta degli impatti del cambiamento climatico con particolare riferimento alla componente vegetazionale ed alla criosfera. Dapprima vengono indicati gli impatti dei cambiamenti climatici del passato, in seguito si descrivono gli impatti del cambiamento climatico attuale a differenti scale geografiche: globale, regionale e locale. Vengono descritti i risultati di ricerche scientifiche effettuate nel territorio del Parco Nazionale dello Stelvio indicando i principali impatti osservati del cambiamento climatico a partire dal 1950 ad oggi e vengono illustrati anche i percorsi di due sentieri tematici: "Il Sentiero della Criosfera" ed "Il Sentiero del Cambiamento Climatico
Ecological responses of plant species and communities to climate warming: upward shift or range filling processes?
No full textThe fate of alpine species in response to climate warming is still unclear. We analyze effects of climate warming on the composition of alpine plants communities and unravel the range filling of communities within a belt from long-term true upward shift processes. In the European Alps we re-sampled in 2003 the vegetation at sites studied in 1953 and analyzed the changes at intra- and inter-community level. Since 1953 all communities experienced a high species turnover, leading to an overall increase in species richness as new species exceeded species losses. The dominant species mainly declined allowing the potential expansion of competitors and/or of new species. The main recruitment sources are neighbor communities within the same elevation belt performing biotic exchanges with other plant communities in the same altitudinal belts. The changes of species distribution curves with elevation emphasized that more than half of the most widespread persisting species exhibited downward shifts instead of upward shifts. Upward shifts from lower elevation belts and of nonnative species were very limited. One third of the persisting species declined and could be used as a proxy to measure the extinction debt. Therefore the fate of plant communities will depend on the ability of the original species to persist and fill the available ecological gaps. Species persistence may be crucial in developing adaptation and environmental protection strategies
La Valle del Foscagno. Archivio del clima del Passato e laboratorio per la conservazione dell'ambiente del Futuro.
No full textIl volume presenta le caratteristiche geomorfologiche e vegetazionali del sito Valle del Foscagno (alta Valtellina) e sintetizza alcuni risultati delle attività di ricerca scientifica svolte nel sito negli ultimi 20 anni
Patterned ground features and vegetation. Examples from Continental and Maritime Antarctica.
No full text- …
