Ellenberg_value<- c( "VOCHTIND", "ZUURGIND", "STIKSIND", "ZOUT_IND")

for (i in Ellenberg_value) {
    Ecobase<- Ecobase[!Ecobase$i== "X",]
    Ecobase<- Ecobase[!Ecobase$i== "?",]
}