Spatial and temporal variations of stygobite Amphipod populations in interstitial aquatic habitats of karst floodplain interfaces in France and Morocco

Artificial substrates buried in stream sediments at the karst/floodplain in terface were used to examine the spatial and temporal variations of the sty gobite Amphipods Niphargus rhenorhodanensis (two stations in France) and Ps eudoniphargus sp (one station in Morocco) populations. One station ("Verna" , France) was supplied by karst water. The other two stations ("Pissoir", F rance and "Grotte du Chameau", Morocco) were supplied by both karst and sur face waters. The dynamics of the populations was found to depend on several interacting factors: spates, geological characteristics, location of the s ediment in relation to karstic water supplies and depth within the sediment .