Diversidad vegetal y tratamientos forestales en parcelas de casta o (Castanea sativa Mill.) de dos regiones mediterráneas

During the last few decades; marked land use changes have taken place throughout the Mediterranean region. These changes have a great impact on plant diversity and also affect the current ecosystem functioning. This is particularly true for sweet chestnut (Castanea sativa Mill.) stands (groves or coppices) that have been more or less abandoned from the end of the last century. Thus; our objective was to analyze consequences on plant species diversity of various management types in chestnut stands of two Mediterranean areas; the Cévennes in France; and Mt. Etna in Italy. Our results indicate that there are few species in common between the two Mediterranean areas; only less than 9%. These differences can be explained by different ecological conditions (climate; soil type; etc.) between the two areas; but also by the differences of management type (groves and coppice stands in the Cévennes; only coppice stands on Mt. Etna) or stand characteristics (shoot density; diameter at breast height; etc.). Moreover; plant species diversity is different according to management types. Indeed; we found that plant species diversity is higher in groves than in coppice stands. VSfe also demonstrated that C. sativa cultivated groves were generally characterized by small heliophilous therophytes. C. sativa abandoned groves; young C. sativa coppice stands were characterized by hemicryptophytes with anemochorous dispersal mode and chamaephytes. Medium and old C. sativa coppice stands (that differ by the shoot age) were more particularly characterized by phanerophytes with zoochorous dispersal mode. A consequence of chestnut stands abandonment is homogeneous vegetation with decreasing plant diversity. One solution could be to maintain a landscape mosaic of diverse chestnut stands diversely modified by human activities. This could allow enhancing the high regional plant diversity. [fr] Ces dernières décades les changements subis dans la région Méditerranéenne ont affecté la diversité végétale dont les variations affectent aussi le fonctionnement des écosystèmes. Ainsi des la fin du siècle dernier les peuplements de chataigniers ont été abandonnés. Notre objectif était d'analyser les conséquences sur la diversité végétale de différents traitements dans deux chataigneraies méditerranéennes des Cévennes (France) et de l'Etna en Italie. Les résultats indiquent qu'il y a peu d'espèces communes aux deux zones d'étude; environ 9%. Ces différences peuvent être justifiées par les facteurs écologiques (climat; sol; etc.) mais aussi par les différences de traitement (plantation pour le fr