Distribution of nitraria retusa in Egypt H. A. Mosallam ... [et al.].

الملخص EN

The present study aims at identifying the distribution behaviour of Nitraria retusa (Forssk.) Asch.

In Egypt to fill the gap of information about this desert shrub.

One hundred and forty-nine stands were sampled to represent the environmental variations associated with the distribution range of this plant in Egypt Mediterranean and Red Sea coasts, Western Desert (oases and southern Sinai).

The application of TWINSPAN and DECORANA multivariate techniques led to identify 7 vegetation groups associated with its distribution in Egypt. These groups are named after their characteristic species as follows: Salsola tetrandra, Nitraria retusa, Bassia indica and Nitraria retusa-Zygophyllum album groups along the Mediterranean coast; Alhagi graecorum group in the oases of the Western Desert; Tamarix nilotica group in many regions; and Nitraria retusa-Zygophyllum coccineum group along the Red Sea coast. The size distribution as indicated by size index of Nitraria retusa population along the Mediterranean coast indicates a stationary shape under salinity levels I (<5 Ms /cm) and II (5-25 mS /cm) and the whole population; while under salinity level III (>25 mS/cm) it had an inverse J-shape indicating the relative preponderance of the small-sized individuals.

Taking into account the Nitraria population along all salinity gradients, it is clear that the medium sized individuals, as represented by classes 2 (100-200 cm) and 3 (200-300 cm), are still more preponderant than the smallest (<100 cm) and biggest ones (>400 cm).

It is concluded that the small-sized individuals of N.retusa along the Mediterranean coast were relatively preponderant than the big ones while the high salinity levels along the red sea coast suppress the recruitment of juveniles.