Search for factors maintaining terricolous bryoflora richness in isolated habitats .2. Comparison between the sclerophyllous oak groves of the occidental border of the Massif des Maures (Var, France) and their interfaces with the vineyard (in French).

Processing (FAC) of 74 bryophytoecological releves from 6 forest structures with Quercus ilex or Quercus suber, isolated within the vineyard near Pierrefeu-du-Var (siliceous substratum), and the outlying contact zones : Prunus spinosa - Rubus or Cistus scrubs (I), bare soils or lawns often rich in ruderal species (i). The confrontation of the bryofloristical and the station data shows that ambient humidity and substratum richness in total nitrogen play an important role in the differenciation of terricolous bryophyte communities. Two forest sets, one humid and rich in nitrogen of organic origin (ubac of Defens du Becasson : surface = 77617 m(2), scrub-layer dense), the other dry and poor in that element (isolates and hedges with a surface less than or equal to 13115 m(2), scrub-layer absent) have been defined whereas a third, very xeric set, groups nearly all releves from the contact zone i, where supply in nitrate fertilizer may be important.