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Titel |
Pollen-based reconstruction of Holocene vegetation and climate in southern Italy: the case of Lago Trifoglietti |
VerfasserIn |
S. Joannin, E. Brugiapaglia, J.-L. Beaulieu, L. Bernardo, M. Magny, O. Peyron, S. Goring, B. Vanniere |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 8, no. 6 ; Nr. 8, no. 6 (2012-12-07), S.1973-1996 |
Datensatznummer |
250005981
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Publikation (Nr.) |
copernicus.org/cp-8-1973-2012.pdf |
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Zusammenfassung |
A high-resolution pollen record from Lago Trifoglietti in Calabria (southern
Italy) provides new insights into the paleoenvironmental and palaeoclimatic
changes which characterise the Holocene period in the southern Italy. The
chronology is based on 11 AMS radiocarbon dates from terrestrial organic
material. The Holocene history of the vegetation cover shows the persistence
of an important and relatively stable Fagus forest present over that entire
period, offering a rare example of a beech woodstand able to withstand
climate changes for more than 11 000 yr. Probably in relation with early
Holocene dry climate conditions which affected southern Italy, the
Trifoglietti pollen record supports a southward delay in thermophyllous
forest expansion dated to ca. 13 500 cal BP at Monticchio, ca. 11 000 cal BP
at Trifoglietti, and finally ca. 9800 cal BP in Sicily. Regarding the human
impact history, the Trifoglietti pollen record shows only poor imprints of
agricultural activities and anthopogenic indicators, apart from those
indicating pastoralism activities beneath forest cover. The selective
exploitation of Abies appears to have been the strongest human impact on the
Trifoglietti surroundings. On the basis of (1) a specific ratio between
hygrophilous and terrestrial taxa, and (2) the Modern Analogue Technique,
the pollen data collected at Lago Trifoglietti led to the establishment of
two palaeoclimatic records tracing changes in (1) lake depth and (2) annual
precipitation. On a millennial scale, these records give evidence of
increasing moisture from ca. 11 000 to ca. 9400 cal BP and maximum humidity
from ca. 9400 to ca. 6200 cal BP, prior to a general trend towards the
drier climate conditions that have prevailed up to the present. In addition,
several successive centennial-scale oscillations appear to have punctuated
the entire Holocene. The identification of a cold dry event around
11 300 cal BP, responsible for a marked decline in timberline altitude and
possibly equivalent to the PBO, remains to be confirmed by further
investigations verifying both chronology and magnitude. Two cold and
possibly drier Boreal oscillations developed at ca. 9800 and 9200 cal BP.
At Trifoglietti, the 8.2 kyr event corresponds to the onset of cooler and
drier climatic conditions which persisted until ca. 7500 cal BP. Finally,
the second half of the Holocene was characterised by dry phases at
ca. 6100–5200, 4400–3500, and 2500–1800 cal BP, alternating with more humid
phases at ca. 5200–4400 and ca. 3500–2500 cal BP. Considered as a whole,
these millennial-scale trends and centennial-scale climatic oscillations
support contrasting patterns of palaeohydrological changes recognised
between the north- and south-central Mediterranean. |
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