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| Titel |
Primary succession on slopes exposed to intense erosion: the case of Vesuvius Grand Cone |
| VerfasserIn |
Adriano Stinca, Giovanni Battista Chirico, Giuliano Bonanomi |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093536
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| Publikation (Nr.) |
 EGU/EGU2014-8360.pdf |
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| Zusammenfassung |
| Mt. Vesuvius (1281 m a.s.l.) is an active volcano dominating the central part of the Campania
Region coastline, with a distinctive barren crater summit, known as Grand Cone, formed
during the eruption of AD 79. Local environmental factors hindered the colonization of the
Vesuvius Grand Cone by vascular plants after the last eruptions of 1906 and 1944.
The Grand Cone exhibits very steep planar slopes (33-35 degrees), covered by
unconsolidated pyroclastic deposits, mainly formed by lapilli and gravels, characterized by an
extremely low water holding capacity and very low organic matter and nitrogen
contents, and exposed to intense water and wind erosion. In the last decade Genista
aetnensis (Biv.) DC. (Fabaceae), has been expanding over the Grand Cone, facilitating
the colonization by other species, especially herbaceous, with a dramatic change
of the landscape appearance of the Vesuvius Grand Cone. G. aetnensis is a plant
endemic of Mt. Etna and Eastern Sardinia and was firstly introduced at the base of Mt.
Vesuvius within reforestation programs after the eruption of 1906. This plant is
a nitrogen fixing species with a strong ability to colonize andosols, much more
pronounced than the indigenous brooms (Cytisus scoparius and Spartium junceum). An
intensive investigation has been conducted to explore the eco-hydrological processes
driving the vegetation dynamics observed on the slopes of Grand Cone. Specific
field surveys and laboratory experiments have been carried out to assess the effects
of the G. aetnensis on soil physical and chemical properties, on the above- and
below-ground microclimate, on the soil hydrological regime and on the distribution of
coexisting species. The G. aetnensis triggers a pedogenetic process that contributes
to a rapid increase of carbon and nitrogen stocks, available phosphorous, cation
exchange capacity and a reduction of soil pH. The increase of carbon content also
significantly improves the water retention properties in this coarse-textured soils,
increasing the soil water content available for plants. Continuous monitoring of the
microclimatic variables, both under and outside the canopy shading, reveals that
the G. aetnensis canopy reduces the air and soil temperatures while keeping air
humidity higher in the warmest hours of the day during the entire growing season, thus
reducing soil water losses by evaporation. During the hottest day of the summer
season, the canopy shading also mitigates the surface soil temperature maxima, which
values outside the canopy shading are prohibitive for the survival of the vascular
plants. Ultimately, the G. aetnensis creates an island of fertility under its canopy, by
ameliorating the soil quality and by creating more favourable microclimate and soil
hydrological conditions under its canopy, determining underneath the canopy a less
stress prone environment that allows the colonization by less stress adapted species. |
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