Structures of tropical dry forests in the Andes: forest conservation, composition and the role of fabaceae and myrtaceae

Background: Tropical Dry Forests (TDFs) are repositories of biodiversity, ecosystem services and carbon that are threatened by fragmentation and climate change. Floristic and phytosociological studies are fundamental database for many studies of conservation and sustainability, but there is a knowledge gap concerning TDFs, especially in the Andes valleys. The aim of this study was to determine the phytosociological structure and composition of woody vegetation of seven TDFs in the Colombian Andes, and because the flora associated with this type of forest has a geographical distribution restricted to each locality where this biome exists, provide information on the main species, genera and families for conservation and restoration actions as well as for future metaanalyses. We sampled seven TDFs with 20 plots of 25 m x 4 m. Results: In the 1.88 hectares of samples, 8422 individuals were surveyed, distributed in 170 species, 120 genera and 50 botanical families. Of these species, 78.82% were identified at the species level, 17.05% at the genus level, and 4.11% at the family level. The most important families were Fabaceae and Myrtaceae. Nitrogen-fixing Fabaceae species were prominent amongst the important species, especially in low altitude and more stressing sites.Conclusion: The structure, composition and ecological importance of these forests must be considered for conservation and ecological restoration plans, in particular the habitat preference of species along the topographic gradient. Particularly noteworthy for conservation are the Myrtaceae species because promote connectivity and regeneration by providing resources for the fauna, a driver of dispersal, as well as nitrogen-fixing Fabaceae species, because promote the resilience and natural regeneration of TDFs in the Andes, a key feature of stability.