The secondary succession was often studied in Mediterranean area though mor
e rarely in Corsica. The aim of this article is to study the joint effect o
f the land abandonment and the mesoclimatic variations between valleys, whi
ch will enable us to outline proposals for a space management of protected
area and for conservation of biodiversity in Corsica mountains. Sites crite
ria and pedological criteria were taken into account on each plot. The anal
ysis of "combined" effect of dynamic stage and valley was carried out by a
"conditional" Factorial Correspondence Analysis (FCA) (inter and intra-clas
ses of the 199 plots and 192 species) in the three sites. The secondary suc
cession is often accompanied by a reduction in the number of species presen
t strictly in a valley.