A. Location of Isalo National Parc in southwestern Madagascar. B. Distribution of the phytogeographic domain in the southern Madagascar showing the incursion of the Central domain (subhumid) in the Isalo massif and Analavelona area; the elevation gap (< 1500 m) between northern and southern mountains let the trade winds blow from east to west. C. Simplified isohyets (mm/year) for the southern Madagascar, from the eastern escarpment to the western coast, showing the highest humidity in Isalo National Park (and Anavelona area) (modified from Guillaumet et al. 2008). D. Profile view of a west–east transect passing through the Isalo massif to the Indian Ocean (Google Earth profile view).