Myrtaceae in the Espinhaço Range: Distribution, Similarity Patterns and Geoclimatic Drivers of Species Turnover Across Different Geomorphological Structures and Vegetation Classes

Abstract The Espinhaço Range (ER), in east Brazil, encompasses a unique biodiversity in a heterogeneous landscape, composed by a mosaic of vegetation classes including campos rupestres, cerrados and forests. Considering the ecological relevance of Myrtaceae and its diversity in these landscapes, we rendered a comprehensive floristic survey of Myrtaceae composition, distribution, and sampling in the ER; we tested if geomorphological structures accurately reflect floristic patterns; and investigated which large-scale environmental variables are correlated to species turnover within its different vegetation classes. Herbarium data were compiled into a comprehensive database, and the floristic patterns were investigated using NMDS and UPGMA. A GDM was used to identify environmental drivers of species turnover. We found 17 genera and 277 Myrtaceae species, of which 53 spp. are new occurrences, and 42 spp. are endemic to the ER. Sampling and diversity were concentrated in the Espinhaço Meridional, Chapada Diamantina and Quadrilátero Ferrífero. We found a higher number of species that are habitat generalists than documented by previous studies. Forests presented the highest richness and the highest number of exclusive species. Caatinga comprehended the lowest richness and the most profound subsampling across different vegetation classes. A latitudinal and longitudinal pattern of floristic similarity was observed; and geomorphological units constituted a fair representation of these patterns. The GDM models were congruent, indicating a mostly edaphically driven species turnover of Myrtaceae across every vegetation class, especially associated with soil texture and geographical distance – constituting the first record of mostly edaphic-driven beta diversity turnover in the Espinhaço Range.