Phytogeographical and phenological comparison of the Meuse and the Saône valley meadows (France)

The meadows of the floodplains of the Saône and the Meuse contain similar ecosystems subject to regular winter and spring flooding. The floristic and faunistic biodiversity decreases with the intensification of agricultural practices. The plant communities show the same zonation along a topographic gradient and have similar floristic progression. Thus, the climatic, biogeographic, human and soil factors have determined the floristic particularities of each valley. The floristic affinities of the two floodplains permitted the comparison of the phenological development of fourteen plant species. Many gaps in the development of species have been observed. These could be explained by the climatic differences betwen the two valleys (sub-Mediterranean influences in the Saône and sub-Atlantic in the Meuse), the existence of different types of soils in each valley (sand part more important in the Saône) and the occurrence of specific ecotypes in each valley.