Demography and size structure of the giant milkweed shrub Calotropis procera (Aiton) W.T. Aiton

Studies on plant population demography and size structure provide important base for monitoring and managing plant species. The present study investigated the monthly variation in plant demography, population dynamics and size structure of Calotropis procera in urban areas, South Cairo, Egypt. Sixty-three permanent quadrats were selected to represent the monthly variation in the characteristics of C. procera population all over one year. The highest plant density was attained in June and the lowest in February and March. The highest biomass was recorded in November, but the lowest in March. The maximum individual’s height was recorded from August to January, while the minimum was in late winter. The monthly size distribution indicated that C. procera had three different size distributions along the whole year: more or less inverse J-shape, positively skewed and bimodal size distribution. The maximum plant survival was correlated with the availability of soil moisture. The demographic flux indicated that the new branches of plant were mainly formed during April and June, followed by significant mortality in July and October. This study may contribute in planning for managing and conserving this medicinal plant.