1990_1991_27_11-49_Ravazzi

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4 min

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Natura Bresciana: la rivista di scienze naturali del Museo

Descrizione

Descrizione
​​LINEAMENTI FISIONOMICI, ECOLOGIA E FATTORI EDAFICI DELLA VEGETAZIONE DI ALCUNI MASSICCI CALCAREO-DOLOMITICI DELLE PREALPI LOMBARDE
I. PRATERIE NATURALI E SEMINATURALI

CESARE RAVAZZI

Riassunto - È stata svolta un'indagine sinecologica sulla vegetazione delle praterie naturali e seminaturali di alcuni massicci calcareo-dolomitici delle Prealpi Lombarde. Sono state identificate alcune tipologie fisionomico-ecologiche, per ciascuna delle quali sono stati descritti i fattori ambientali salienti.

Abstract - Physiognomical features, ecology and geopedological factors of the vegetation of some calcareous-dolomitic massifs in the Lombard Pre-Alps (Northern ltaly ). 1. Natural and seminatural grasslands. Natural and semi-natural grassland vegetation of calcareous-dolomitic Lombard Pre-Alps has been investigated, with synecological approach. Some physiognomical and ecological types have been identified and environmental factors have been described.
A. Under the timberline:
- discontinuous xerophylous sedge communities, dominated by Carex mucronata and creeping chamaephytes, and Festuca alpestris formation on extremely dry ridges with discontinuous soils.
- Festuca spectabilis formation, pioneering dry stabilized detritus in mountain belt.
- Sesleria varia-Carex humilis thermophilous communities, with Bromus erectus codominance, widely diffused on steep sunny slopes with grey rendzina, in the submediterranean belt.
- Caricion austroalpinae calcophilous communities. Sesleria-grasslands, rich in prealpine endemie element, are situated on cool slopes at low altitudes too. They are marked by Molinia coerulea. In the Fagus belt, Caricion austroalpine communities spread also in southern exposition. Here the Ses/eria-vegetation is qualified by an endemie group that takes the piace of thermophilous submediterranean elements.
- Molinia coerulea neutral-acidic communities, on low permeability soils («Terra Rossa» and its colluvium; soils on glacial deposits) and M. coerulea hygrophilous communities, along little valleys close to perennial springs, in the submediterranen belt.
- Schoenus nigricans hygrophilous formation, strictly connected with dripping springs, on travertines or hydromorphyc soils.
B. Above the timberline:
- Caricion austroalpinae calcophilous communities. The most widespread type is Carex sempervirens and S. varia dry grassland, rich in prealpine endemie element. I​t characterizes sunny slopes. Helictotricon parlatorei becomes dominant where the substratum is highly percolating. On the contrary, at higher humidity, on humiferous soils in the high-mountain-subalpine belt, Carex austroalpina-grassland is observed.
- Carex sempervirens-Festuca curvula pastures, on developed soils.
- Carexfirma microtherme grasslands are divided according to chorological and ecologica! characters of the endemie element: 1) Relic communities, restricted on humid cliffs, especially in the «external bell» of the Pre-Alps; 2) Detritus pioneer type, in the «internai belt».

Ultimo aggiornamento

14/10/2014, 13:45