The ever changing conditions and strict rules also affect the flora in Aldabra... They are coded to survive, even with the tiniest bit of soil around their roots, salt sprays and strong sun.
In addition, similarly to the inner islands, the southeast monsoon provides very little fresh water in the southern atolls. For some of the species the way of adaption is to loose their leaves and going back to the "stand-by". After, when the rains of the northwestern monsoon approach the islands, they start to flourish again.
Photos and info source: SIF