Changes in the abundance of arbuscular mycorrhizal (AM) spores and root colonization that occurred in the postcultivation phase were investigated in the coastal dunes of the Seyhan Delta, Turkey. A sampling method was used to obtain community-level information, which is essential for the evaluation of relations between plant communities and AM colonization. Eight quadrats of 10 x 10 m were selected to describe floristic composition of different plant communitie. TWINSPAN was applied to identify the plant communities. In addition, DECORANA was employed to put forward a clear ordination of the communities. Soil samples were collected at depths of 0-20 cm from each quadrat, and site conditions were described by means of soil analyses such as extractable P (NaHCO,), pH, organic matters, and salinity (%). Differences were detected in the floristic composition of the vascular plant cover in quadrats located in the abandoned peanut-cultivated fields when compared with control quadrats. This difference occurred with an increase of weeds and decrease of native psammophytes in terms of species richness and relative coverage. Higher AM colonization rates were found in the abandoned fields than in the undisturbed sand dunes. These rates were associated with the amount of 13205 and organic matters. It was concluded that the increase in those rates was a result of overfertilization and introduction of weeds. Transport of manure into dune fields enhances the potential for the introduction of weed seeds and results in further development of mycorrhizal symbiosis through rapid weed colonization. AM colonization rate (%) was detected to be much higher on fibrous and rhizomatous roots than tap and bulbous roots, respectively. The highest values of AM colonization were detected on the species belong to the family Gramineae.