The number of species increases with age on backfilled land. firstly, rapid recolonization by vegetation is explained by the arable soil that has been preserved. It contains the seeds or the strains of the species. It is explained by:
- the anthropization of natural formations: wood cutting and other
- the abundance of hydrophile species (panicum sp; Spermacoce rueilla; Hydrophila sp...) on backfilled sites,
- the abundance of field species (Musa paradisiaca; Corchorus olitorius...) and fallow species (Passiflora foetida; Malvastrum coromandelianum.. ) on backfilled sites.