Scielo RSS <![CDATA[Acta Botanica Brasilica]]> vol. 29 num. 2 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Bryophyte and pteridophyte spores and other palynomorphs in quaternary marine sediments from Campos Basin, southeastern Brazil: Core BU-91-GL-05]]> This paper presents morphological descriptions and ecological data of cryptogam spores and other non-pollen palynomorphs from Quaternary sediments of Campos Basin, Rio de Janeiro, SE Brazil. The ages were derived from biostratigraphy of planktonic foraminifers and two radiocarbon dates, and suggest that sediment deposition started in the last 140,000 years BP. Thirty different types of palynomorphs were identified, described, and photographed: two bryophyte spores (sensu lato); 21 pteridophyte spores; four freshwater microalgae; onePseudoschizaea; and two microfungi. Some of the identified spores (Sphagnum, Blechnum, Cyatheaceae, Dennstaedtiaceae, Lycopodiella, Microgramma, Polypodium, Acrostichum, Pityrogramma, and Lygodium) are related to the modern flora found on the northern coast of Rio de Janeiro State, at the Restinga of Jurubatiba, from vegetation types such as shrub swamp/coastal swamp formation, seasonally flooded forest, Clusia and Ericaceae woods, and disturbed vegetation. The freshwater microalgae and the microfungi are also presently recorded from the coastal lagoons of this region. The high spore concentration in slope sediments reflects the intense terrigenous influx, caused by a relative low sealevel during glacial stages. Palynological analysis suggests the presence of taxa from flooded forests and humid areas in the coastal plain during glacial and interglacial stages of the Late Pleistocene. <![CDATA[ERIOCAULON L. from Brazil: An annotated checklist and taxonomic novelties]]> Eriocaulon is an aquatic and cosmopolitan genus with 478 species. It is characterized by diplostemonous flowers and free petals with a black gland at the apex. There are few taxonomists studying Eriocaulon from Brazil. The species of this genus remain barely delimited, with inconsistent descriptions, and nomenclatural types not assigned or located. The analysis of nomenclatural types, specimens in scientific collections, and protologues enabled the recognition of 53 species of Eriocaulon from Brazil. Thirteen new synonyms and the elevation of five varietes to species level are proposed. Comments on taxonomy, geographic distribution, habitat, life form, and conservation category are provided. <![CDATA[The role of temporal scale in linear edge effects on a submontane Atlantic forest arboreal community]]> This study aims to detect the composition, abundance patterns, and successional stage distributions exhibited by arboreal species inside and at the linear edge of a submontane seasonal forest in the Chapada Diamantina (12°28'31'S, 41°23'14'W), Bahia, Brazil. The individual plants with breast height diameters ≥5 cm were sampled in 30 quadrats (10 m × 10 m), 15 in the forest edge and 15 inside the forest. Species were classified according to successional category. Phytosociological and diversity indices were calculated. Shannon indices were compared using Hutcheson's t-test, and the remaining parameters were analyzed by ANOVA. Linear edges exerted a high impact on the floristic composition, diversity, and abundance of species, though little interference was observed in the structure of the community, since phytosociological parameters and the proportions of successional categories did not differ between the edge and inner forest fragment. The impact of linear infrastructure was similar to that of other border types. Additionally, even though the distance between forest fragments was very short, an edge effect was observed, which underlines the importance of linear forest edges to biodiversity conservation. <![CDATA[Hydraulic architecture of lianas in a semiarid climate: efficiency or safety?]]> Xylem anatomical traits can provide insights regarding the mechanisms affecting the distribution of vascular plants across environmental gradients. In this study, we aimed to investigate the hypothesis that lianas occurring in semiarid environments have characteristics that maximize the xylem resistance to tension-induced cavitation along the root-stem-branch continuum. To gather information regarding the hydraulic architecture of the lianas, we analyzed several anatomical traits of wood: cross-sectional area occupied by the parenchyma (AP), fibers (AF), and vessels (AV); average vessel diameter (d); wood density (WD); pit diameter in the vessel wall (dpit); pit density (Npit), and potential hydraulic conductivity (Kp) in branches, stems, and roots of three congeneric species of lianas that occur in two vegetation types of the semiarid regions of Brazil. We found that lianas in these semiarid environments possess a number of the following xylem traits that may allow resistance to tension-induced cavitation:1) lower vessel diameter, lower Kp, and higher hydraulic safety in roots and branches; 2) Dimorphic vessels, ensuring both hydraulic efficiency and safety; and 3) small diameter of pits (potentially associated with a decrease in the membrane area of the vessel pits). This suite of traits may provide insight into mechanisms allowing lianas to occur in semiarid environments. <![CDATA[Simultaneous dehydration and infiltration with (2-hydroxyethyl)-methacrylate (HEMA) for lipid preservation in plant tissues]]> Although this study aims to develop an improved method for the preservation of reserve lipids in plant tissues for different uses in plant anatomy, it mostly aims to develop an improved method for the identification of lipid reserves where synthesis or storage occurs. The proposed procedures entail only the utilization of (2-hydroxyethyl)-methacrylate (HEMA) as a dehydration agent. One of the procedures is based on the gradual exchange of aqueous HEMA solutions with increasing concentrations. In another procedure, dehydration and infiltration are induced by the presence of silica gel around a modified microcentrifuge tube containing the aqueous HEMA solution with the plant tissues, thus allowing efficient lipid preservation. Both procedures resulted in simultaneous dehydration and infiltration of the endosperm and embryo of Ricinus communis, while eliminating the use of ethyl alcohol, thus providing better lipid preservation. <![CDATA[Invasion impact by Pteridium arachnoideum (Kaulf.) Maxon (Dennstaedtiaceae) on a neotropical savanna]]> Whether management intervention is required to control biological invasions depends primarily on demonstrating species losses resulting from such invasions. Brackens of the Pteridium genus are currently regarded as a problem species that act as important ecological filters in the assembly of invaded communities. We investigated the effects of Pteridium arachnoideum invasion on the diversity, structure, floristic composition, and functional traits of cerradão in Assis, São Paulo, Brazil. We compared an invaded site with an adjacent non-invaded site. Bracken constrained the establishment of tree species, resulting in a community structure remarkably distinct from the non-invaded area. The density and basal area of the arboreal community were higher in non-invaded areas, but large trees were more frequent in the invaded areas. However, bracken did not reduce tree species diversity. Both richness and diversity were higher in the invaded area, indicating that over time, tree species richness and diversity naturally recovered, albeit slowly, in the invaded area. Therefore, one cannot attribute the loss of richness in the Cerrado vegetation to bracken invasion. Hence, we argue that, in this system, eradication of this invasive species is not likely to be cost effective, and thus, it should be a low management priority. <![CDATA[The effects of fragmentation on Araucaria forest: analysis of the fern and lycophyte communities at sites subject to different edge conditions]]> Edge effects impact species richness and composition as a result of environmental changes caused by fragmentation. This study analyzed edge effects on a community of terrestrial ferns and lycophytes in an Araucaria forest in Brazil at sites subjected to differing edge conditions: (1) a site bordering a road running through the interior of a conservation unit, and (2) a site bordering an agricultural property. Twelve 10 × 10 m plots were selected at the edge and in the interior of each site, and accounted for a total of 48 plots. The edges had lost their characteristic floristic identity, suggesting that many species are sensitive to variations in environmental conditions. The edge effect had a negative impact on species richness as shown by the greater average numbers of fern and lycophyte species in forest interiors at both sites. The results showed that the forest fragments in contact with agricultural areas were subjected to more intense edge effects than the fragments bordering a road within a conservation unit. <![CDATA[Soil and leaf nutrient content of tree species support deciduous forests on limestone outcrops as a eutrophic ecosystem]]> The leaf and soil nutrient status of plants has been used to infer structural and functional aspects at the ecosystem level. Such data are available for tropical and savanna systems growing on poor and acidic soils; however, information for species growing on eutrophic and basic soils is lacking. Deciduous tropical forest is one of the most endangered types of tropical forest, and despite the high level of attention aimed at it, little is known about the nutritional composition of its leaves. Here, we provided information on leaf nutrient content ratios and relationships for deciduous tree species growing on a limestone outcrop in Central Brazil. We compared our data on soil and leaf macronutrient concentration with previously published data from savannas and humid forests in the Neotropics. We found that deciduous forest tree species possessed elevated concentrations of N, K, and Ca compared with those of other forest and seasonal systems. The higher leaf Ca and P is due to the elevated Ca and P content in soils of deciduous forest. We discussed these findings in the light of soil aspects, functional adaptations, and priorities that should be given to the conservation and management of deciduous forest. <![CDATA[Plant diversity in hedgerows amidst Atlantic Forest fragments]]> Hedgerows are linear structures found in agricultural landscapes that may facilitate dispersal of plants and animals and also serve as habitat. The aim of this study was to investigate the relationships among diversity and ecological traits of woody plants, hedgerow characteristics (size, age, and origin), and the structure of the surrounding Atlantic Forest landscape. Field data were collected from 14 hedgerows, and landscape metrics from 1000-m buffers surrounding hedgerows were recorded from a thematic map. In all sampled hedgerows, arboreal species were predominantly zoochoric and early-succession species, and hedgerow width was an important factor explaining the richness and abundance of this group of species. Connection with forest vegetation did not explain richness and abundance of animal-dispersed species, but richness of non-zoochoric species increased in more connected hedgerows. These results suggest that hedgerows are probably colonized by species arriving from nearby early-succession sites, forest fragment edges, and isolated trees in the matrix. Nonetheless, hedgerows provide resources for frugivorous animals and influence landscape connectivity, highlighting the importance of these elements in the conservation of biodiversity in fragmented and rural landscapes. <![CDATA[Local extinction of an important seed disperser does not modify the spatial distribution of the endemic palm Astrocaryum aculeatissimum (Schott) Burret (Arecaceae)]]> Spatial pattern of the palm Astrocaryum aculeatissimum was investigated in an urban Atlantic Forest fragment (Tijuca National Park, Brazil) where its main seed disperser, the red-rumped agouti Dasyprocta leporina, is locally extinct. A 120 × 130 m plot (1.56 ha) was established in which all A. aculeatissimum individuals were quantified, georeferenced, and classified by ontogenetic stages, namely, seedling, infant, juvenile, immature individual, and adult. Analyses were performed using Ripley's K function. We recorded 376 individuals, most of which were in the juvenile stage (n = 228). The spatial pattern was aggregated as observed for other palm species. Seedlings and infants were not associated with adults, whereas juveniles and immature individuals were observed closer to adults than expected. The distance between each seedling and the nearest adult ranged from 3 to 30 m (mean ± sd = 11.8 ± 7.8), which is similar to the agouti dispersal distances reported in other studies. Despite the importance of agoutis for the seedling recruitment of A. aculeatissimum, their short-term absence does not affect the spatial distribution of this palm in the studied area. <![CDATA[How are legal matters related to the access of traditional knowledge being considered in the scope of ethnobotany publications in Brazil?]]> Legal measures, such as the use of free or prior and informed consent, return of research results to communities (which can be understood as "sharing of benefits," according to Brazilian legislation), and research authorization by governmental bodies, are mentioned and regulated in various documents, either governmental or specific, within the area of ethnobiology. This study aims to explore how these matters are considered in the scope of published ethnobotany articles in Brazil, as well as whether the creation of the Provisional Measure 2.186-16/2001 has contributed to the national advance of these matters. The methodology comprised a literature review of articles focusing on medicinal and food plant resources in the prominent Brazilian journals which publish ethnobotany studies. From 137 articles analyzed, 8 mentioned the return of research results to the community; 21 explicitly cited the use of free or prior and informed consent; and 13 mentioned the authorization of governmental bodies. We expect that the present study will contribute to the debate regarding the necessity of reformulation of the current system, which would guarantee a more effective rapport between the government, researchers, local communities, and society and contribute to the development of ethnobotany in Brazil. <![CDATA[Consequences of suppressing natural vegetation in drainage areas for freshwater ecosystem conservation: considerations on the new "Brazilian forest code"]]> The input of particulate and dissolved organic matter (POM and DOM, respectively) from terrestrial ecosystem drainage basins is an important energy and nutrient source in limnic food chains. Studies indicated that semi-deciduous seasonal forests located in drainage areas in Brazil have the potential to produce 7.5 - 10.3 Mg ha−1/year of POM. The global increase in vegetation destruction, such as forests, threatens this allochthonous resource and can have significant impacts on river and lake communities and food chains. Therefore, it is critical that exploitation and occupation protocols are updated to protect the transition areas between terrestrial and limnic ecosystems. This review highlights the existing knowledge of these ecosystem interactions and proposes responsible sustainable methods for converting the vegetation in drainage basins. This was based on Brazilian ecosystem data and the new "Brazilian Forest Code." This study also considers the importance of including flood tracks in permanently protected areas to improve Brazilian legislation and protect hydric resources. <![CDATA[Edge effect on vascular epiphytic composition in a fragment of Atlantic Forest in northeastern Brazil]]> Epiphytes are common in the canopy of temperate and tropical forests, where they substantially contribute to species diversity and to key ecosystem processes. However, little is known about the effects caused by deforestation on this group of species, especially in northeastern Brazil, an area experiencing intense anthropogenic pressure. This study aimed to evaluate the effect of environmental variables on the structure of assemblies of vascular epiphytes in a fragment of open ombrophilous forest, Areia, northeastern Brazil. Sixty 10 × 10 m sampling plots were installed to cover different environments within the fragment. The relationship between environmental variables and species composition was evaluated by means of a generalized linear mixed model. The composition of assemblies of epiphytes differed with respect to distance from the edge and luminosity. In the study area, deforestation led to a change in the composition of epiphytic species both at the edge and the interior of the fragment. <![CDATA[Relationship between gall-midge parasitism, plant vigor, and developmental instability in Ouratea polygyna Engl (Ochnaceae) in a patch of a Brazilian Atlantic Forest]]> We tested the preference prediction of plant vigor hypothesis by examining the relationship between gall occurrence and leaf size. We also examined the effect of galls on leaf asymmetry, which is a measure of developmental instability. Gall occurrence did not increase with leaf size, thereby providing no support to the preference prediction. Galled leaves were significantly more asymmetric than ungalled leaves. Moreover, leaf asymmetry increased with both gall occurrence and gall size, indicating that galls boosted the stress levels in Ouratea polygyna. <![CDATA[Fruit set of distylous Psychotria carthagenensis Jacq. (Rubiaceae) mediated by Apis mellifera (Apidae) and species of Augochloropsis (Halictidae)]]> Heterostyly is a floral polymorphism consisting in the presence of two morphs in the population that differ reciprocally in the position of their sexual organs. Heterostylous species depend on visitors to produce fruits, but the efficiency of insect species as pollinators greatly varies and depends on the morph visited. The aim of the present study was to determine the effect of a single visit by the bees Apis mellifera and species of Augochloropsis on the fruit set of the distylous species Psychotria carthagenensis. After a single visit from each bee species, flowers were bagged to monitor the fruit set. Pollination effectiveness between pollinators and morphs was compared. The results of the experiments were compared with data from manual intermorph cross-pollination using the G test. There were no significant differences in the fruit set between treatments (insect visit and cross-pollination), and between flowers visited by Augochloropsis spp. and flowers visited by A. mellifera. Our results suggest that pollination effectiveness of the studied bees was not related to floral morph, and that both exotic and native bees showed similar performances on the fruit set of P. carthagenensis. <![CDATA[Pollen types used by Centris (Hemisiella) tarsata Smith (1874) (Hymenoptera, Apidae) in the provisioning of brood cells in an area of Caatinga]]> The aim of this study was to identify, by sediment pollen analysis, the plant species used as floral resources for the provisioning of brood cells in Centris (Hemisiella) tarsata, in an area of Caatinga, within the municipality of Nova Soure, Bahia State, Brazil. The analysis of pollen contents from three brood cells revealed 11 pollen types, corresponding to four botanical families. Malpighiaceae was represented most, followed by Leguminosae, Ochnaceae, and Solanaceae, the latter two represented by just a single pollen type each. On the basis of the percentages in the samples, it was possible to infer that C. tarsata visited distinct plants, but intensified its pollen collection in species related to Aeschynomene martii and Solanum paniculatum pollen types, which are considered the most important pollen sources in the larval diet of this bee. In addition to the pollen sources, we have also recorded seven pollen types regarded as oil ones, all related to the Malpighiaceae family. The information about the resources for C. tarsata can be of great relevance, in view of the importance of these bees in the pollination of native flora.