La banque édaphique de diaspores de bryophytes de l’écosystème du chêne vert au bois d’Astros (commune de Vidauban, Var, France)
Cultivation for 4 months, under controlled conditions, of 22 core samples of soils (from the surface down to 3-4 cm depth) from each of the 3 stages of the dynamics of the holm oak (Quercus ilex L. ) ecosystem at the bois d’Astros, near Vidauban (Var), shows that the edaphic diaspore bank of bryophytes is about as rich in species as the surface communities at the boring points (surface/soil bank, holm oak forest: 8/8 species, Rosmarinus garrigue: 15/11, Brachypodium phoenicoides lawn: 11/12). It consists mainly of mosses, 50 to 58% of which are found only in the soil. Among these, the presence of oligotrophic species of open habitats (Trichostomum brachydontium, Philonotis arnellii, Funaria grex muehlenbergii and the liverwort Riccia sorocarpa) that occur below ground in the Quercus ilex forest is remarkable, whereas soil cores from the garrigue and the lawn have given Bryum radiculosum and Pseudocrossidium hornschuchianum which, like the 4 preceding taxa, are lacking in the above ground inventories (surface: 100 m2) carried out on the site in the holm oak ecosystem. Our results confirm that the proportion of acrocarpous mosses belonging to the colonist life strategy tends to be more important below than above ground, whereas the reverse is true for pleurocarpous perennials. There is also an increase in the percentage of colonists present in the soil, when passing from the forest to the garrigue and the lawn.