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Inselbergs sensu lato are isolated, mainly granitic and gneissic, rock outcrops, forming old landscape elements on crystalline continental shields on all continents. Mats consisting mainly of monocots occur on open rocky slopes, forming a conspicuous habitat on these outcrops. Brazilian lowland inselbergs consist of species-rich mats with large numbers of endemics and Bromeliaceae standing out as characteristic elements in these communities. For the first time, we provide a checklist of mat-forming bromeliads on lowland inselbergs in Brazil and investigate whether the regional species pool influences the species diversity of inselberg mats. Furthermore, through modelling analysis, we looked for the potential distribution of bromeliads endemic to inselbergs, expecting that they would show a narrower niche width than non-endemic species. Our data indicate the existence of a particular phytogeographical region in the Atlantic Forest in south-eastern Brazil, comprising inselbergs harbouring a highly diverse flora of Bromeliaceae, which we call Sugar Loaf Land. In addition, our projections reveal smaller predicted areas for bromeliads endemic to inselbergs compared with non-endemic species, the former apparently being mainly controlled by climatic factors. In addition to climate and regional species pools, the island-like character of inselbergs seems to play an important role in the speciation of rupicolous Bromeliaceae.

Isolated monoliths of granitic and/or gneissic rock rising abruptly from the surrounding landscape are known as inselbergs. Dome-shaped inselbergs are common throughout the Atlantic Forest in south-eastern Brazil, a region known as Sugarloaf Land (SLL). This study aimed to create the first checklist of vascular plant species occurring on lowland inselbergs in SLL, with a focus on vegetation islands. We used information from online databases, our own field sampling and data from previously-published studies. We found 548 vascular plant species (505 angiosperms; 43 ferns and lycophytes) belonging to 69 families and 212 genera. Of all identified species, 536 are native and 12 are naturalised. We updated the information currently available in Flora do Brasil 2020, as 59% of the angiosperms and 63% of the ferns and lycophytes on our checklist were not previously characterised as occurring on rock outcrops. As a first step towards generating a Virtual Herbarium of lowland inselberg vascular plants, we added barcode vouchers with images available online for 75% of the total number of vascular species. In the official lists of endangered species, 115 angiosperms and five ferns and lycophytes are mentioned. However, the conservation status of many species have not yet been evaluated (77% angiosperms; 88% ferns and lycophytes), thus this list is an important step towards their conservation. The information provided herein is essential for management programmes related to rock outcrops in Brazil as they are facing serious threats to conservation.

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Inselbergs are granitic or gneissic rock outcrops, distributed mainly in tropical and subtropical regions. Th ey are considered terrestrial islands because of their strong spatial and ecological isolation, thus harboring a set of distinct plant communities that diff er from the surrounding matrix. In Brazil, inselbergs scattered in the Atlantic Forest contain unusually high levels of plant species richness and endemism. Th is study aimed to inventory species of vascular plants and to describe the main habitat types found on an inselberg located in the state of Minas Gerais, in southeastern Brazil. A total of 89 species of vascular plants were recorded (belonging to 37 families), of which six were new to science. Th e richest family was Bromeliaceae (10 spp.), followed by Cyperaceae (seven spp.), Orchidaceae and Poaceae (six spp. each). Life forms were distributed in diff erent proportions between habitats, which suggested distinct microenvironments on the inselberg. In general, habitats under similar environmental stress shared common species and life-form proportions. We argue that fl oristic inventories are still necessary for the development of conservation strategies and management of the unique vegetation on inselbergs in Brazil.