PALEOSUOLI ED ALTRI ARCHIVI PALEOAMBIENTALI PER LA RICOSTRUZIONE DELLE FLUTTUAZIONI OLOCENICHE DELLA TREELINE ALPINA E APPENNINICA
Tesi di Dottorato
Data di Pubblicazione:
2012
Citazione:
PALEOSUOLI ED ALTRI ARCHIVI PALEOAMBIENTALI PER LA RICOSTRUZIONE DELLE FLUTTUAZIONI OLOCENICHE DELLA TREELINE ALPINA E APPENNINICA / C. Compostella ; tutor: L. Trombino ; coordinatore: E. Erba. DIPARTIMENTO DI SCIENZE DELLA TERRA "ARDITO DESIO", 2012 Feb 08. 23. ciclo, Anno Accademico 2010. [10.13130/compostella-chiara_phd2012-02-08].
Abstract:
The aim of this research is the reconstruction of Holocene environmental changes at the treeline in three study areas along a gradient from continental to oceanic climate; the study was carried out in two areas in the Central Italian Alps (Valtellina and Val Camonica) and in one in the Northern Apennines (Mt. Cusna area).
To outline the complex interactions between soil, vegetation, climate and human activity, a multidisciplinary approach was necessary, combining pedological and paleopedological investigation, soil micromorphology, pedoanthracology, macroremains analysis and dendrochronology.
Firstly, we characterized current soils to outline present relations between soil, climate and vegetation. These results were necessary to correctly interpret data from the subsequent paleosol analyses. Paleopedological study, through the identification of forest paleosols above the current treeline, allowed to identify the altitudinal shift of the treeline during the Holocene. Micromorphological analyses highlighted processes driving soil development; we could analyze the parent material effect on soil development, correlate different sampling site and identify different climatic phases that have affected study areas.
Macroremains and charcoals analyses allowed to reconstruct vegetation compositions during the different climatic phases. Macroremains analysis was performed on peat samples and allowed a detailed environmental reconstruction. Charcoals were extracted from soil samples and were identified to reconstruct forest composition at the treeline; we performed also the identification of insect exoskeleton fragments found in soils, which provided detailed paleoecological information.
Dendrochronological analysis was performed along altitudinal transects, in order to estimate the effect of the current warming on vegetation and to assess how treelines respond to climate change, in order to better interpret data about the past fluctuations.
In the Alpine sites we focused on Podzols, typical soils linked to conifer forest cover; podzols were sampled at different elevations, along an altitudinal transect from closed forest to alpine grassland; we compared their macroscopical, physical, chemical and micromorphological characteristics, to asses if the profiles above the present treeline are in equilibrium with the present environmental conditions or if they are relict soils formed under more favorable climate conditions with higher treeline. Our analysis confirmed the second hypothesis; Podzol above present treeline are relict soil, very well preserved, with the same translocation rate of the lower ones and without traces of regressive pedogenesis. The identification of relict Podzols allowed to estimate a minimum rise of 250 m of the treeline probably during the Holocene climatic optimum.
In this study area we performed also a macroremains analysis in two peatlands, to correlate vegetation history with forest paleosols; a tree log found at the base of one peat section was AMS dated to 9090y cal BP, suggesting that the rise of the treeline to higher elevations occurred in the early Holocene.
On the Apennines we performed two main studies, the first with multidisciplinary approach (field observation, pedoanthracological analysis, soil micromorphology and dendrochronology) to reconstruct Late Holocene soil evolution and environmental changes at the treeline, and the second with micromorphological approach, to outline processes of soil evolution and to outline how micromorphology can help in reconstructing environmental change in areas where paleosols are available as proxy archives.
In the first study, we described nine soil and paleosols profiles across the present treeline; physical and chemical analyses, pedoanthracological and micromor
Tipologia IRIS:
Tesi di dottorato
Keywords:
paleosols ; treeline ; Alps ; Apennines ; micromorphology ; pedoanthracology ; macroremains ; soil science ; paleoenvironment ; Holocene
Elenco autori:
C. Compostella
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