Seasonal turnover in floristic composition of flooding savannas in arauca, Colombia

Abstract

Changes in the floristic composition in flooded savannas in Arauca (Arauca, Colombia) were described and correlated with annual rain patterns. We surveyed the vegetation to determine species richness, relative abundances and the Importance Value Index (IVI) using eleven-point line transects and eleven 1 m2 plots every two months for a year. 110 species were recorded, and there was a positive correlation between the monthly precipitation and the abundance of individuals in the vegetation community. The higher values of species richness (96) occurred during the wet season compared to the dry season species richness (57). Also, the wet season rank abundance curve had higher evenness compared to the dry season curve. Species that were dominant during the dry season included Hydrolea spinosa, Melo-chia spicata, Peltaea sessiliflora, Cyperus luzulae, Acroceras zizanioides, and Andropogon bicornis. 53 species were exclusive to the wet season and fourteen to the dry season. This study shows the high botanic biodiversity that can be found in the Orinoco savannas.