White-sand Vegetation Research Articles

Checklist e distribuição geográfica das espécies de Myrtaceae que ocorrem em campinaranas da Amazônia brasileira

ABSTRACT White-sand vegetation (campinarana) is a type of vegetation restricted to oligotrophic and highly leached white sand soils in the Amazon phytogeographic domain that includes grassland to forest phytophysiognomies. Campinaranas cover about 5% of this phytogeographic domain and are impacted by various anthropic activities that put plant species, especially endemic ones, at risk. Myrtaceae has significant representativeness in oligotrophic edaphic environments, but floristic and taxonomic studies on the family in campinaranas are still few and geographically limited. We present a checklist of Myrtaceae species known from campinaranas of the Brazilian Amazon based on the survey of herbarium specimens and literature data in order to assess the level of endemism of these species for this vegetation type. We compiled occurrence records of 72 species and six genera. Myrcia and Eugenia were the genera with the highest number of species. Overall, 38 species (53%) occurred only in the Amazon and two were endemic to campinaranas (Eugenia campina and Myrcia psammophila). Four species are new records for the Brazilian Amazon: Blepharocalyx salicifolius, Eugenia hatschbachii, Myrcia anceps and Myrcia racemosa. The specific richness of Myrtaceae in Brazilian campinaranas is likely to be underestimated since extensive areas, especially those farther from the riverbanks, in the states of Amazonas and Roraima, have not yet been intensively surveyed.

Beta diversity and microhabitat use of ant assemblages in a white-sand vegetation gradient in central Amazonia

Beta diversity and microhabitat use of ant assemblages in a white-sand vegetation gradient in central Amazonia

Black Manakin (Xenopipo atronitens) as a keystone species for seed dispersal in a white-sand vegetation enclave in Southwest Amazonia

Black Manakin (Xenopipo atronitens) as a keystone species for seed dispersal in a white-sand vegetation enclave in Southwest Amazonia

Hidden biodiversity of Amazonian white-sand ecosystems: two distinctive new species of Utricularia (Lentibulariaceae) from Pará, Brazil.

As deforestation and fire move forward over pristine vegetation in the Amazon, many species remain undiscovered and may be threatened with extinction before being described. Here, we describe two new species of Utricularia (Lentibulariaceae) collected during recent fieldwork in an area of white-sand vegetation in the eastern Amazon Basin named Campos do Ariramba. Further herbarium revision revealed that both species were first collected over 60 years ago in the same area, remaining unnamed until now. The new species, named U. arirambasp. nov. and U. jaramacarusp. nov., are placed in U. sect. Aranella and U. sect. Setiscapella, respectively. We provide full descriptions, illustrations, photographs, a distribution map, and taxonomic discussion for both species. Additionally, we provide a preliminary list of Lentibulariaceae from the Campos do Ariramba. Both new species are assessed as Vulnerable, however, yet known only from a few collections each, highlighting the urgency and importance of fieldwork and taxonomic revisions in the Amazon biogeographic region in order to provide essential data for the conservation of both known and still unknown biodiversity.

A first record of Loricalepis (Melastomataceae) from the Brazilian Atlantic Forest, with the description of a new species from Bahia

Loricalepis has been known from only three collections from the upper Rio Negro, in Amazonas, Brazil, and the Rio Guainia basin, in Colombia, all belonging to a single species, L. duckei. Its capsular fruits and cochleate, tuberculate seeds suggest its relation to pantropical “core Melastomeae”, but it does not have a particularly close morphological connection with any other genus of the tribe. Here we describe and illustrate a second species in the genus, Loricalepis atlantica, recently collected in white sand vegetation near the coast of Bahia. Although we have not been able to sequence DNA from the new species, we place it in Loricalepis due to a long list of characters that it shares with L. duckei. Both are shrubs or small trees with scalariform indumentum on the stems and leaves; thick-cartilaginous, crenulate-serrulate and paleaceous-ciliate leaf margins; persistent acute and seta-tipped sepals; glandulose-ciliate petal margins; glabrous and subisomorphic stamens, these with the connective not at all or only shortly prolonged and ventrally bilobed; and the ovary apex with a crown of scales surrounding the style. lightface differs from L. duckei by 5-merous flowers (vs. 4-merous in L. duckei), the hypanthium covered with minute scalariform trichomes (vs. glabrous), light-pink petals (vs. white), purple anthers (vs. white), and 5-celled ovary (vs. 4-celled). The new species is known from only one locality, in an extremely endangered vegetation type. Its discovery highlights the need for sustained floristic studies of forest remnants in northeastern Brazil.

<p><strong><em>Myrcia psammophila</em></strong><strong> (Myrtaceae), a new species from the Amazonian white-sand vegetation</strong></p>

The new species Myrcia psammophila is here described, illustrated and compared with M. grandis and M. umbraticola, two morphologically similar taxa. It may be distinguished from these two latter species based on possession of leaves with corky petiole and raised midvein adaxially, and distinctly pedicellate flowers with squared staminal ring and sepals united at the base. This species is endemic to a region of lower Rio Negro and inhabits areas of white-sand vegetation.

A new record and emended description of a rare Amazonian white-sand species: Schoepfia clarkii (Schoepfiaceae)

Schoepfia clarkii is a rare species of Schoepfiaceae that to date has been known only from the single flowering specimen used in the original description from white-sand vegetation in Venezuela. Here we report new records for this species collected from the lower Negro River basin in Brazil, ca. 900 km from the type locality, but also from white-sand vegetation. We provide a more detailed description of the species, including the first observations of fruit characters, as well as illustrations, photographs, a distribution map, and discussion of its conservation status. We also provide a key for the identification of the South American species of Schoepfia.

Distribution and status of Turdus thrushes in white-sand areas of eastern Colombia, with a new subspecies of T. leucomelas.

White-sand areas in the Colombian Amazon harbor many endemic and specialist species that are relatively little studied with respect to their ecology, distribution and zoogeographic affinities, for example Turdus thrushes. A recent expedition to the Serranía de Chiribiquete, a mountain range of Guianan origin in the Colombian Amazon, resulted in the discovery of an enigmatic Turdus thrush restricted to white-sand vegetation. Molecular phylogenetic analyses of the ND2 gene revealed that this population is genetically similar to T. leucomelas albiventer, from which it differs in its smaller size and darker, duller plumage. Therefore, we here describe this population as a new subspecies of T. leucomelas. Furthermore, our inspection of specimens of Turdus taxa from eastern Colombia revealed the existence of sympatry between T. ignobilis debilis and T. i. arthuri at two sites. Based on this evidence and previously documented genetic and phenotypic differences, we recognize T. arthuri as a distinct biological species. We analyze distributions and measurements of functional traits among four thrush taxa of eastern Colombia.

White sand vegetation in an Amazonian lowland under the perspective of a young geological history.

What controls the formation of patchy substrates of white sand vegetation in the Amazonian lowlands is still unclear. This research integrated the geological history and plant inventories of a white sand vegetation patch confined to one large fan-shaped sandy substrate of northern Amazonia, which is related to a megafan environment. We examined floristic patterns to determine whether abundant species are more often generalists than the rarer one, by comparing the megafan environments and older basement rocks. We also investigated the pattern of species accumulation as a function of increasing sampling effort. All plant groups recorded a high proportion of generalist species on the megafan sediments compared to older basement rocks. The vegetation structure is controlled by topographic gradients resulting from the smooth slope of the megafan morphology and microreliefs imposed by various megafan subenvironments. Late Pleistocene-Holocene environmental disturbances caused by megafan sedimentary processes controlled the distribution of white sand vegetation over a large area of the Amazonian lowlands, and may have also been an important factor in species diversification during this period. The integration of geological and biological data may shed new light on the existence of many patches of white sand vegetation from the plains of northern Amazonia.

Avifauna of a white-sand vegetation enclave in north-west Rondônia, Brazil: relevant records, body mass and morphometrics

White-sand vegetation (WSV) enclaves occur throughout Amazonia. WSV, known in Brazil as campina or campinarana, possesses peculiar floral and faunal communities, different from those in adjacent forests but with biogeographic affinities to those in similar ecosystems far distant. Recent ornithological studies of these ‘islands’ have yielded new taxa for science and enabled a better understanding of the zoogeography of many poorly known species in Amazonia. Here we report the results of an ornithological survey of a campinarana enclave in north-west Rondonia, southern Amazonian Brazil. The area was inventoried three times in 2010–12, totalling 899 net / hours and 110 hours of observations. A total of 171 bird species was identified, belonging to 44 families. Among them, at least nine species are closely associated with WSV: Green-tailed Goldenthroat Polytmus theresiae, White-fringed Antwren Formicivora grisea, Natterer's Slaty Antshrike Thamnophilus stictocephalus, Black Manakin Xenopipo atronitens, Plain-crested Elaenia Elaenia cristata, Pale-bellied Mourner Rhytipterna immunda, Campina Flycatcher Cnemotriccus fuscatus duidae, Plush-crested Jay Cyanocorax chrysops diesingii and Red-shouldered Tanager Tachyphonus phoenicius. Approximately 8% of the species recorded are migratory, most of them austral migrants. In addition, body mass and morphometrics of 136 individuals from 55 species are presented. Our results augment ornithological knowledge in Rondonia, aid our understanding of regional zoogeography, and serve as an alert to the need to preserve a region that has suffered severe anthropogenic impacts for >100 years.

Flesh flies (Diptera: Sarcophagidae) from a white-sand habitat in the Brazilian Amazon, with the description of four new species.

The white-sand enclaves in the Amazon Basin are small areas scattered through the tropical forest, with sandy and nutrient-poor soils and an unusual vegetation type. The insect fauna of this ecosystem is poorly known, especially in the eastern Amazon. The flesh fly fauna of an area of open herbaceous white-sand vegetation known as "Campo Redondo" in the municipality of Cametá, state of Pará, was surveyed, resulting in the discovery of 43 species in 11 genera representing the subfamilies Sarcophaginae and Miltogramminae. Four new species are described: Dexosarcophaga (Dexosarcophaga) campina sp. nov., Helicobia cametaensis sp. nov., Helicobia domquixote sp. nov., and Metopia fofo sp. nov. Lepidodexia (Lepidodexia) grisea Lopes and Lepidodexia (Notochaeta) setifrons (Lopes) are newly recorded from Brazil. Dexosarcophaga (Bezzisca) ampullula (Engel), D. (Dexosarcophaga) transita Townsend and Titanogrypa (Cucullomyia) larvicida (Lopes) are newly recorded from the Brazilian Amazon.

Floristic composition, structure and soil-vegetation relations in three white-sand soil patches in central Amazonia

ABSTRACT The Amazonian white-sand vegetation presents a set of unique features, such as the dominance of a few species, high endemism and low species richness, which differentiate it from other Amazonian forests. Soil parameters have long been recognized as the main drivers of white-sand vegetation (WSV) characteristics. However, how they influence the composition, richness and structure of this vegetation type is still poorly understood. In this study we investigated the variation in floristic composition between patches and the soil-vegetation relations in three central Amazonian WSV patches. We tested whether slight differences in soil properties are linked with differences in floristic composition, species richness and forest structure in adjacent patches. In each patch three plots of 50 x 50 m were sampled (a total of 2.25 ha). Soil samples were collected for each plot. The sampling cutoff for arboreal individuals was DBH ≥ 5 cm. We sampled a total of 3956 individuals belonging to 40 families and 140 species. In each patch only a few species were dominant, but the dominant species varied among patches. Differences among patches were significant, but plots in the same patch tended to have similar species composition. The variable sum of bases (SB) was directly related to species composition, however, species richness and forest structure were not related to soil parameters. Even small variations in soil parameters can change species composition in WSV, although these variations do not necessarily influence the richness and other structural parameters.

A new species of Saxofridericia subgenus Acrotheca (Rapateaceae) from Amazonas State, Brazil

Saxofridericia brasiliensis P.E.Berry & Krahl, a new species of Saxofridericia subgenus Acrotheca, is described and illustrated. It is most closely related to Saxofridericia aculeata Körnicke, but differs in its entire-margined leaves and narrower leaf blades. It is so far known only from white-sand campina vegetation north of Manaus along the Caracaraí highway in Amazonas State, Brazil.

Two new endemic species of Caraipa (Calophyllaceae) from the Central Amazon Basin, Amazonas State, Brazil

Two new species of Caraipa (Calophyllaceae) are described and illustrated: Caraipa glabra and C. iracemensis. Both species are known only from the municipality of Presidente Figueiredo, Amazonas state, Brazil. They both occur on patches of white-sand vegetation and they are locally abundant. Caraipa glabra is a small tree and can be distinguished from other Caraipa species by the complete absence of hairs on the leaf lamina, pedicel and fruits. Caraipa iracemensis is morphologically similar to C. grandifolia and C. caespitosa, and can be distinguished by its habit, leaves and petiole size, as well as fruit surface and size.

Soil-vegetation relationships and community structure in a "terra-firme"-white-sand vegetation gradient in Viruá National Park, northern Amazon, Brazil

Viruá National Park encompasses a vast and complex system of hydromorphic sandy soils covered largely by the white sand vegetation ("Campinarana") ecosystem. The purpose of this study was to investigate a vegetation gradient of "terra-firme"-white sand vegetation at the Viruá National Park. Nine plots representing three physiognomic units were installed for floristic and phytosociological surveys as well as to collect composite soil samples. The data were subjected to assessments of floristic diversity and similarity, phytosociological parameters and to statistical analyses, focused on principal components (PC) and canonical correspondence analysis (CCA). The vegetation of the Campinaranas types and Forest differed in biomass and species density. Ten species, endemic to Brazil, were particularly well-represented. PC and CCA indicated a clear distinction between the studied plots, based on measured soil variables, especially base sum and clay, which were the most differentiating properties between Campinarana and Forest; For the separation of the Campinarana types, the main distinguishing variable was organic matter content and cation exchange capacity. Higher similarity of Campinaranas was associated to a monodominant species and the lower similarity of Forest was related to the high occurrence of locally rare species.

Four new species of Caraipa (Calophyllaceae) from the Amazon basin and the Guiana Shield

Four new species of Caraipa (Calophyllaceae) are described and illustrated: Caraipa balbinensis, endemic to Balbina (Presidente Figueiredo, Amazonas, Brazil), C. caespitosa growing in savannah and white-sand vegetation in Roraima and Amazonas (Brazil), Guainía (Colombia) and Amazonas (Venezuela), C. davilae, an endemic species of Loreto (Peru), and C. macrocarpa, an endemic species to Guyana. Morphological comparisons with the similar taxa are provided for each new species: C. balbinensis can be distinguished from C. heterocarpa by its longer leaves and petioles, and its slightly rugulose fruit surface; C. caespitosa can be separated from C. grandifolia and C. longipedicellata by its distinguished habit, and its smaller leaves and inflorescences; C. davilae differs from C. balbinensis and C. grandifolia by its dense indument on the abaxial leaf surface, and its rugulose and concave fruit valves; and C. macrocarpa can be distinguished from C. punctulata by its large, glabrous and rugulose fruits.

Impact of sedimentary processes on white-sand vegetation in an Amazonian megafan

Abstract:Amazonian white-sand vegetation has unique tree communities tolerant to nutrient-poor soils of interest for interpreting processes of adaptation in neotropical forests. Part of this phytophysionomy is confined to Late Quaternary megafan palaeo-landforms, thus we posit that sedimentary disturbance is the main ecological factor controlling tree distribution and structuring in this environment. In this study, we characterize the topographic trend of one megafan palaeo-landform using a digital elevation model and verify its relationship to the forest by modelling the canopy height with remote sensing data. We also compare the composition and structure (i.e. canopy height and diameter at breast height) of tree groups from the outer and inner megafan environments based on the integration of remote sensing and floristic data. The latter consist of field inventories of trees ≥ 10 cm dbh using six (500 × 20 m) plots in várzea, terra firme and igapó from the outer megafan and 20 (50 × 20 m) plots in woodlands and forests from the inner megafan. The unweighted pair group method with arithmetic mean (UPGMA) and the non-metric multidimensional scaling (NMDS) were applied for clustering and dissimilarity analyses, respectively. The megafan is a sand-dominated triangular wetland with a topographic gradient of < 15 cm km−1, being more elevated along its axis. The outer megafan has a higher number of tree species (367), taller canopy height (mean of 14.1 m) and higher diameter at breast height (mean of 18.2 cm) than the white-sand forest. The latter records 89 tree species, mean canopy height of 8.4 cm and mean diameter at breast height of 15.3 cm. Trees increase in frequency closer to channels and toward the megafan's axis. The flooded and nutrient-poor sandy megafan substrate favoured the establishment of white-sand vegetation according to the overall megafan topography and morphological heterogeneities inherent to megafan sub-environments.

Isolation and characterization of polymorphic microsatellite DNA Markers from an Amazonian white-sand vegetation specialist bird,Xenopipo atronitens(Aves: Pipridae)

ABSTRACT Thirteen novel polymorphic microsatellite loci were isolated and characterized from the Amazonian Black Manakin, Xenopipo atronitens. The loci were screened using 30 samples from Brazil. A total of 13 loci were variable with number of alleles per locus ranging from 2 to 17, whilst the observed and expected heterozygosities varied from 0.067–0.900 and 0.310–0.910, respectively. Five loci deviated significantly from the Hardy–Weinberg equilibrium, whereas one pair of loci deviated significantly from linkage disequilibrium. The set of markers will be a useful tool for future population genetic and kinship studies of X. atronitens, an Amazonian white-sand vegetation specialist.

What is the avifauna of Amazonian white-sand vegetation?

SummaryWhite-sand vegetation (WSV) is a rare vegetation type in the Amazon basin that grows in nutrient impoverished sandy soils that occur as patches of variable size. Associated with this vegetation is bird assemblage that has not yet been fully characterized. Based on published species inventories and our own field data we compile a checklist of bird species recorded in WSV. In addition, we compared the avifauna of WSV with that found in savanna patches, another type of Amazonian open vegetation. WSV hosted a distinctive avifauna including endemic and threatened species. The number of bird species was lower in WSV compared to nearby terra firme forests, seasonally flooded forests and Amazonian savannas. Despite its low diversity, the avifauna of WSV has a distinctive species composition and makes a significant contribution to Amazonian beta diversity. At least 35 bird species can be considered as indicator species for this environment. Previously identified areas of endemism within the Amazon basin house at least one WSV indicator bird including cases of congeneric species with allopatric distributions. Seven of the WSV indicator species (20% of this avifauna) are in an IUCN threatened category, with one speciesPolioptila clementsiconsidered Critically Endangered. Their isolated distribution, small area occupied, and fragility to human-driven disturbances makes WSV one of the most threatened vegetation types in the Amazon basin. The study of WSV avifauna contributes to a better understanding of mechanisms that generate and maintain species diversity as well as of the environmental history of the most biologically diverse biome of the planet.

Miconia macuxi (Miconieae, Melastomataceae): a new species from the Amazonian white sand vegetation

Miconia macuxi is described from the states of Roraima and Amazonas, in northern Brazil, and Atabapo and Amazonas, in southern Venezuela. It occurs in white sand vegetation, and can be recognized by the strongly discolorous leaves with dense stellate trichomes on their abaxial surfaces, secund inflorescences, petal margins with glandular-stipitate trichomes, and white stamens, the antepetalous with the connective with two ventral lobes and a dorsal tooth.