The specialized white-sand flora of the Uatumã Sustainable Development Reserve, central Amazon, Brazil

The consensus is that Amazonian white-sand ecosystems (campinaranas) shelter several endemic plant species. However, recent studies have shown that most species are generalists, and they also occur in other Neotropical ecosystems. To investigate this issue, we analyzed the proportion of endemic/specialist species in a checklist of trees, palms, and shrubs sampled between 2014 and 2020 in campinarana patches of the Uatumã Sustainable Development Reserve (USDR), central Amazon. We also provide a description of phytophysiognomies, habitats, distribution, and phenology. We found 167 species belonging to 117 genera and 50 families. Fabaceae was the most representative (21 spp.), followed by Rubiaceae (16 spp.) and Chrysobalanaceae (10 spp.). We found that 30.5% of the species were exclusive to campinaranas, confirming that although there are many endemics, proportionally most species are generalists. The USDR has a rich flora specialized in oligotrophic habitats, which must be considered in the management and conservation strategies of these complex and fragile Amazonian ecosystems.