-(Tropical inselbergs: habitat types, adaptive strategies and diversity patterns). Inselbergs are isolated rock outcrops that rise abruptly above the surrounding plains. Granitic and gneissic inselbergs are geologically and geomorphologically old and occur throughout a broad spectrum of climatic zones. They form microclimatically and edaphically dry growth sites that support a highly specialized vegetation. Based on physiognomic criteria a number of habitat types can be distinguished that are widespread on inselbergs (e.g. ephemeral flush vegetation, monocotyledonous mats, rock pools). Three hot spots of global inselberg plant diversity can be identified which are both rich in species and endemics: a) southeastern Brazil, b) Madagascar and c) southwestern Australia.Key words -adaptive traits, conservation, endemics, rock outcrops, species richness RESUMO -(Inselbergs tropicais: tipos de hábitats, estratégias adaptativas e padrões de diversidade). "Inselbergs" são afloramentos rochosos isolados que emergem abruptamente acima das planícies que os cercam. Inselbergs graníticos e gnássicos são geologicamente e geomorfologicamente antigos e ocorrem ao longo de um amplo espectro de zonas climáticas. Eles formam sítios de crescimento que são microclimaticamente e edaficamente secos, e sustentam uma vegetação altamente especializada. Vários tipos de hábitats podem ser distinguidos, com base em critérios fisionômicos, que são comuns a vários inselbergs (e.g., vegetação de floração efêmera, "tapetes" de monocotiledôneas, "panelas" rochosas). Três regiões importantes do mundo com diversidade de vegetais típicos de inselbergs, podem ser apontados, que são ricos tanto em espécies quanto em endemismos; são elas: a) o sudeste do Brasil, b) Madagascar e c) o sudoeste da Austrália.Palavras-chave -afloramentos rochosos, características adaptativas, conservação, endemismos, riqueza de espécies
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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