Distribution patterns of Astragalus in the old world based on some selected sections

The geographic distribution of Astragalus L. (Fabaceae) was analyzed using a database of 12377 geo-referenced observations. In the old world (including Asia، Africa and Europe) there are ca. 2900 euploid species classified in 166 distinct sections. In this study using geographic information system (GIS) by means of DIVA-GIS (ver. 4) distribution map of some more important sections in the old world was illustrated. A grid of 50 × 50 km cells were used to map the biodiversity and species richness. These maps showed west Asia with over half of all species and ca. 1000 endemics is most significant region. Our studies demonstrated biodiversity centers of Astragalus chiefly located in Iran and Afghanistan. Complementarily analysis for determining conservation management priorities according to mathematical models (Rebelo Algorithm) has been done and locations were illustrated on map. Rare species were specified based on extent of distribution area، number of observations and maximum distance between observations of each species. Also، variations of species richness along with increasing of altitude indicated that ecological optimum for Astragalus is ca. 2000 m. In conclusion based on our present-only data and “Ecological Niche Modeling”، predictive distribution map for the entire old world using BIOCLIM model has been provided.