The present paper aims to characterize some biological and ecological traits of three threatened species, namely; Phlomis aurea, Pterocephalus sanctus, and Thymus decussatus inhabiting the mountains of Southern Sinai, in Saint Catherine Protectorate. The study included aspects of phenology, seed germination, and restoration of species from the soil seed bank. The effect of short-term fencing on productivity and annual growth rate was tested. The results of seed germination showed the highest ratio (66%) by Phlomis aurea in dark incubator at constant temperature without pretreatment. Non-treated seeds of Pterocephalus sanctus showed a comparable ratio (64%) in room conditions. However, Thymus decussatus seeds showed lower ratio (up to 36%) after washing seeds by dripping water for 24 hrs. Seedlings of Phlomis aurea had been succesfully recruited from the soil seed bank. The mean productivity values of P. sanctus showed a positive response under a short-term fencing, while Ph. aurea and T. decussatus showed a negative response. On the other hand Phlomis aurea populations showed a positive trend in the annual grouth rate, under short-term fencing, however, T. decussatus populations remained almost steady. On the other hand, P. sanctus showed a growing trend in open localities more than under fenced ones. Concerning the reproductive effort, the highest value (16%) was obtained by T. decussatus, while the lowest value (10 %) was obtained by Ph. aurea, and P. sanctus was intermediate (13%). The study recommended for application of the soil seed bank techniques, as effective tools for restoration of target plant species and for nature conservation.