Applying a floristic originality index in tropical forests of south Sinaloa, Mexico

Sinaloa is among the states of Mexico harboring the highest deforestation rates. Reforestation programs have been put up in south Sinaloa with species chosen for their high seedling rates, structural importance or strong restoration value. However, species criteria such as level of endemism as well as rarity appear to be underestimated. Eight sampling sites were randomly selected and a botanical survey was carried out at least every month from 2015 to 2017. In order to rank species over conservation stakes, a Floristic Originality Index method was elaborated using species level of endemism, rarity and conservation status. The floristic inventory enabled the identification of a set of 250 species with the Fabaceae being the most represented family with 51 species. Using the Floristic Originality Index, a subset of 51 species was selected as priority for conservation along with 23 other species all displaying characteristics of “framework” species. Features of reproduction and types of ideal soil conditions for reforestation are presented for each species. The method developed to determine floristic originality has proven a set of most vulnerable and rare species to select “priority” and “framework” tree species able to restore forests structure and biodiversity as well as ecosystem functions. This evaluation is made from a conservation biology point of view and appears to be well adapted for studies at a local scale.