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RESUMO O objetivo deste estudo foi realizar o levantamento de samambaias e licófitas do Morro do Pico (22°56'05.2''S,43°07'13.8''W), que está localizado na Área de Proteção Ambiental dos Fortes, litoral do município de Niterói, Estado do Rio de Janeiro, Brasil. A área é formada por afloramentos rochosos e remanescentes de Mata Atlântica adjacente. As coletas foram realizadas entre o mês de maio a outubro de 2014, o material foi herborizado e depositado no herbário do Museu Nacional (R). A chave de identificação é apresentada com base em características morfológicas diagnósticas. Foram encontradas dez famílias, distribuídas em quinze gêneros, totalizando vinte e seis espécies. As famílias com maior riqueza foram Pteridaceae (10 spp.), Anemiaceae (quatro spp.) e Selaginellaceae (três spp.). A mata adjacente apresenta maior riqueza em relação ao inselberg. Dentre os táxons encontrados somente nesta formação, destacam-se Anemia tomentosa var. anthriscifolia, Doryopteris collina, Selaginella convoluta e S. sellowii. ABSTRACT This study aimed to inventory the ferns and lycophytes of Morro do Pico (22°56'05.2'' S, 43°07'13.8''W), which is located in Fortes Environmental Protection Area, in the coastal region of Niterói, in Rio de Janeiro State, Brazil. This area is formed by a rocky outcrop and an adjacent Atlantic Forest remnant. Fieldworks were carried out from May to October 2014, the material was dried and incorporated to the Herbarium from Museu Nacional (R). The identification key is presented according to diagnostic morphological characters. We record ten families, distributed in fifteen genera and twenty-six species. Families with highest species richness were: Pteridaceae (10 spp.), Anemiaceae (four spp.) and Selaginellaceae (three spp.). The adjacent forest presents greater richness in relation to the inselberg. Among the taxa found only in this formation, it stands out Anemia tomentosa var. anthriscifolia, Doryopteris collina, Selaginella convoluta e S. sellowii.

Espírito Santo is a hotspot of diversity in the Atlantic Forest in Brazil, where five new species of Vernonieae from the genera Cololobus, Lepidaploa, Lessingianthus, Piptocarpha, and Vernonanthura were found, and four of them occur in the municipality of Santa Teresa. These discoveries show that current knowledge on biodiversity in Espírito Santo is incipient, even in sites with decades of biological inventories, such as Santa Teresa. Here, all five species are described with comments about distribution, conservations status, phenology and taxonomic affinities. We also provide illustrations and a distribution map of the new species. According to the criteria of IUCN red list, Cololobus argenteus and Vernonanthura spathulata must be included in endangered (EN) category. Resumo Espírito Santo é um hotspot de diversidade da Floresta Atlântica no Brasil, onde cinco novas espécies de Vernonieae dos gêneros Cololobus, Lepidaploa, Lessingianthus, Piptocarpha e Vernonanthura foram encontradas, e quatro delas ocorrem no município de Santa Teresa. Essas descobertas mostram que o conhecimento atual em biodiversidade no Espírito Santo é incipiente, mesmo em locais com décadas de inventórios biológicos, como em Santa Teresa. Aqui, todas as cinco espécies são descritas com comentários sobre distribuição, status de conservação, fenologia e afinidades taxonômicas. Nós também fornecemos ilustrações e um mapa de distribuição das novas espécies. De acordo com os critérios da lista vermelha da IUCN, Cololobus argenteus e Vernonanthura spathulata devem ser incluídas na categoria de ameaçada (EN).

International audience; While spiders constitute the most abundant and diverse arthropods in many habitats, they remained under-studied, especially in tropical rainforests. The goal of this study is to assess the spatial distribution of the spider family Ctenidae by assessing associations of species diversity and population traits among different habitat conditions. Fieldwork was carried out during 2013 in habitats varying in flooding frequency (plateau vs. flooded forest) and elevation (inselberg vs. lowland) in the Nouragues National Natural Reserve, French Guiana. Assemblage composition, population structure, and trait measurements of one dominant species were assessed using hand collection in replicated quadrats. We found strong effects on ctenid assemblages attributable to both elevation and flooding, with changes in relative abundance of species among habitats, but few correlated densities between species. At the population level, main differences in species distribution between and within habitats were detected only when juveniles were taken into account. No effect of elevation was found on the measurements of traits of the dominant species, but legs were proportionally shorter in flooded habitats, suggesting reduced active dispersal in these habitats. Our study highlights the value of complementary of measures of diversity and traits at different biological scales in Ctenidae. © 2018 Istituto per lo Studio degli Ecosistemi of the Consiglio Nazionale delle Ricerche, Firenze.

We provide a floristic inventory of Angiosperms from rocky outcrops of the Área de Proteção Ambiental Pedra do Elefante, Espírito Santo, Brazil. Fieldwork was performed monthly from March/2015 to July/2016. A checklist with 302 species belonging to 219 genera and 74 families is provided. Bromeliaceae, Orchidaceae, Fabaceae, Euphorbiaceae, Apocynaceae, Asteraceae, Cactaceae, Convolvulaceae, Rubiaceae, Bignoniaceae and Cyperaceae are the richest families with around 50% of the listed species. One hundred forty seven species are exclusively rupicolous, 125 spp. exclusively terricolous, 26 spp. are epiphytes, and six species are found as both rupicolous and terricolous. Phanerophytes and chamaephytes were predominant life forms. Our results added 18 new records to the Espírito Santo state, indicated the occurrence of nine endemic species for the state and noticed that only 55 taxa of the total of species have threat assessments according to IUCN. Resumo O objetivo deste trabalho foi realizar o inventário florístico das Angiospermas dos afloramentos rochosos da Área de Proteção Ambiental Pedra do Elefante, Espírito Santo, Brasil. Expedições de coleta foram realizadas mensalmente de março/2015 a julho/2016. Um total de 302 espécies pertencentes a 219 gêneros e 74 famílias foram encontradas. Bromeliaceae, Orchidaceae, Fabaceae, Euphorbiaceae, Apocynaceae, Asteraceae, Cactaceae, Convolvulaceae, Rubiaceae, Bignoniaceae e Cyperaceae são as famílias mais ricas com cerca de 50% de representatividade das espécies listadas. Os táxons exclusivamente rupícolas são representados por 147 espécies enquanto 125 spp. São exclusivamente terrícolas, 26 spp. são epífitas e seis espécies são encontradas como tanto como rupícolas quanto terrícolas. As formas de vida predominantes foram fanerófitas e as caméfitas. Nossos resultados adicionaram 18 novos registros ao estado do Espírito Santo, indicaram a ocorrência de nove espécies endêmicas para o estado e indicam que apenas 55 táxons do total de espécies encontradas possuem avaliações de quanto às categorias de ameaça de acordo com a UICN.

International audience; The Guianas have often been proposed as a forest refugium; however, this view has received little testing. Studies of population genetics of forest taxa suggest that the central part of French Guiana remained forested, while the southern part (currently forested) may have harboured more open vegetation. Insights into the population structure of species restricted to non-forested habitats can help test this hypothesis. Using six microsatellite loci, we investigated the population genetics of French Guianan accessions of Manihot esculenta ssp. flabellifolia, a taxon restricted to coastal savannas and to rocky outcrops in the densely forested inland. Coastal populations were highly differentiated from one another, and our data suggest a recent colonization of these savannas by M. esculenta ssp. flabellifolia in a west-to-east process. Coastal populations were strongly differentiated from inselberg populations, consistent with an ancient separation of these two groups, with no or low subsequent gene flow. This supports the hypothesis that the central part of the region may have remained forested since the last glacial maximum, impeding the establishment of Manihot. Contrary to coastal populations, inselberg Manihot populations were strikingly homogeneous, at a broad spatial scale. This suggests they were connected until recently, either by a large continuous savanna area, or by smaller, temporary disturbed areas shifting in space.

A new genus and species, Spinochactas mitaraka gen. n., sp. n. (Chactidae) are described from the Mitaraka Massif in French Guiana, a site located near the borders of French Guiana, Brazil, and Suriname. The description of the new genus and species brings further evidence of the biogeographic pattern of distribution presented by some elements of the family Chactidae endemic to the Tepuys or to the Inselberg formations of South America.

International audience; We questioned whether and how plant communities vary in space and time along an inselberg-rainforest ecotone in relation to present-day warming and whether biotic and non-biotic factors could explain the observed patterns. The study took place on a granitic inselberg in the French Guianan (South America) rainforest (Nouragues Natural Reserve: 4°5'N, 52°41'W). In a diachronic study (1995-2005) embracing a severe El-Niño event in 1997, we analysed vegetation structure and composition along three transects subsuming whole environmental and topographical variations in the transition zone from shrub vegetation at the fringe of open-rock vegetation to tall-tree rainforest. Data were analysed by PCA. Major variations in species and trait distribution were described in the low forest, with two floristic types evidenced by first PCA component and verified by cluster analysis: one with floristic composition reminiscent of open-rock vegetation but with higher and continuous canopy, the other typical of the low forest. There is no clear-cut boundary between typical open-rock and low forest vegetation. Variation in species composition of typical low forest was evidenced by second PCA component, which displayed differences according to slope and altitude. Small (~1.5 m), although significant, shifts in the spatial distribution of plant species pointed to possible slow encroachment of typical low forest vegetation in the absence of disturbance. However, the stability of species and trait distribution was remarkable within the 10-yr interval considered, despite an otherwise recorded decrease in species richness and recruitment. The boundary between typical low forest and open-rock-like vegetation coincided with the spatial limit of the mineral soil above granite. Despite demographic accidents due to severe El Niño events, plant communities at the fringe of a tropical inselberg are stable at short-time both in composition and spatial distribution. In the absence of strong disturbances such as wildfire and further erosion, soil availability for roots could be interpreted as an environmental constraint to the successional development of forest vegetation. Soil development might thus act as an ecological barrier to forest encroachment, which could only be alleviated by erosion recovery, as otherwise demonstrated.

From the summit downslope a granitic inselberg in French Guiana, soils and vegetation evolve from bare granite covered by cyanobacteria, to a savannah-type vegetation on thin patchy sandy accumulations, then to a low forest on shallow young soils and to a high forest on deep highly weathered ultisols. We have used element budgets and Sr isotopic variations in soils and plants to investigate the mineral nutrient supply sources of the different plant communities. Granite and atmospheric deposition have 87Sr/86Sr ratios of 1.3 and 0.71, respectively. The 87Sr/86Sr ratio of cyanobacteria (0.72) suggests granite weathering by cyanobacteria crusts. The 87Sr/86Sr ratio of the savannah-type vegetation is 0.73 and varies between 0.75 and 0.76 in the low and high forest leaf litter regardless of soil depth, age and degree of impoverishment. These almost constant ratio suggest that forest Sr comes from rainwater and from the summit of this inselberg, where it is released and redistributed along the slope, by surface flow, lateral redistribution of litter, and mineral particles. However, because of its very low content in the rock and soils, Ca is supplied to plants by atmospheric deposition., Du sommet vers la base d’un inselberg granitique (Nouragues, Guyane Française), les sols et la végétation évoluent depuis des savanes sur des ilots sableux entre les affleurements rocheux couverts de cyanobactéries, vers une forêt basse sur sols peu épais, riches en minéraux altérables puis une forêt haute sur sols très profonds et altérés. Les variations isotopiques du strontium des sols et des plantes ont été mesurées pour rechercher les sources de nutriments des différentes communautés végétales. Les rapports 87Sr/86Sr du granite et des dépôts atmosphériques sont respectivement de 1,3 et 0,71. Le rapport 87Sr/86Sr des cyanobacteries (0,72) suggère une libération de Sr par altération du granite. Le rapport 87Sr/86Sr de la savanne est de 0,73 et varie entre 0,75 et 0,76 dans les litières de forêt basse et haute, quelle que soit la profondeur, et la richesse en minéraux altérables des sols. La faiblesse et l’homogénéité surprenante de ces rapports suggèrent une alimentation en Sr des forêts essentiellement à partir de dépôts atmosphériques et des sols de la partie haute de l’inselberg, via des écoulements de surface, des redistributions latérales de litière et de particules minerales lors de crises érosives. Cependant, en raison de l’extrême pauvreté de la roche et des sols en calcium, le Ca des communautés végétales provient de la pluie.