A Brazilian bioregionalization reappraisal based on Angiosperm distribution: a biogeographical and conservation overview

Bioregionalizations constitute an important tool to synthesize biodiversity knowledge, essential for conservation planning. Bioregions currently recognized in the Neotropics have been delineated using different methods and biologicalgroups, frequently suggesting conflicting results. This study aimed to reevaluate the circumscription of bioregions using the distribution of angiosperm species. Angiosperm records were compiled from online herbaria and filtered fortaxonomical and geographical accuracy according to Flora e Funga do Brasil. A network analysis was performed with InfoMap Bioregions and similarity amongst recognized bioregions was evaluated with an Unweighted Pair Group Method with Arithmetic Mean. Beta diversity patterns were modelled using Generalized Dissimilarity Modelling (GDM) and five climatic variables. A conservation overview was constructed comparing sampling, conservation coverage, deforestation and fire occurrence across bioregions. Seven bioregions were identified and hierarchically clustered: Brazilian subregion (subdivisions not recovered in our analysis); Chacoan subregion, comprised of the Chacoan dominion (four provinces) and the Paraná dominion (two provinces). GDM recognized other heterogeneous areas within these bioregions. The Paraná dominion presented the largest historical anthropization, the Chacoan dominion presented the highest density of fire spots, and the Brazilian subregion had the highest coverage of conservation units while encompassing unknown biodiversity.