While Switzerland presents a great Bryodiversity, some important aspects of Bryophyte ecology are almost unknown. Bryophyte flora of arable fields has been particularly neglected and studies are of great interest since numerous species can inhabit this type of open environment. Moreover, because of the reduced competition and the notable predictability of life conditions, some endangered Bryophytes species could maintain viable populations in this type of artificial and extensively simplified landscapes, particularly on temporarily flooded soils. 16 Bryophytes species have been sampled in 5 stability-contrasted stations of the Chablais vaudois. The stations were visited twice (spring and summer) and the dynamic of these communities has been extrapolated from these data. Attempts to (i) link the species sampled in the Chablais vaudois with described phytosociological associations and (ii) explain their distribution by simple ecological factors such as plowing frequency and soil water content are discussed. Since these factors are strongly implicated in ecosystem stability and predictability, they select species with adapted life strategies and are thought to be relevant to explain a great part of the observed diversity and dynamic of arable field Bryophyte communities.