Resumo em Inglês:

ABSTRACT The green algal genus Bryopsis has simple morphology and high phenotypic plasticity, making it difficult to identify its species based on morphological characteristics alone. This study evaluated the diversity of Bryopsis in northeastern Brazil (the State of Pernambuco), based on morphological and molecular data using the markers tufA and rbcL. Molecular analyses were incongruent with morphology, demonstrating the existence of cryptic and polymorphic species in the genus. Of the four taxa cited for the area based only on morphological data (Bryopsis corymbosa, B. pennata, B. plumosa, Bryopsis sp.), only B. pennata was recorded. Typical specimens of B. pennata and B. plumosa were grouped with low genetic divergence, 0-0.21 % for tufA and no divergence for rbcL, indicating that B. pennata is an extremely plastic species that includes specimens with morphotype B. “plumosa”. Bryopsis pennata var. secunda is cited for the first time for northeastern Brazil, with divergence from the typical variety of 0.96-1.57 % for tufA and 0.4 % for rbcL. This study showed that broader sampling of Bryopsis is necessary in order to confirm the taxonomic status of the species referenced for Brazil, whose phenotypic plasticity may cause overestimation of diversity or reveal cryptic species.

Resumo em Inglês:

ABSTRACT There is a knowledge gap regarding the influence of bamboos on natural regeneration. This study evaluated how abundance, richness, dominance, evenness, diversity of the seed bank and biotic and abiotic factors (e.g., canopy opening, herbaceous cover, and litter thickness), differ between bamboo dominated (B) and non-dominated (NB) areas. The study was conducted in a fragment of Semideciduous Seasonal Forest surrounded by an agricultural landscape. Soil samples were taken at 20 points in each area at two time periods, to evaluate the seed bank. The results show that diversity and structural parameters of the seed bank differ between areas and time periods. There was higher abundance and richness of seedlings of herbaceous ruderal species in area B and a greater abundance of seedlings of arboreal species in area NB. Sampling points in the bamboo dominated area had greater canopy openings and greater cover by herbaceous species, facilitating the establishment of individuals belonging to the families Poaceae and Cyperaceae, which could have competitive advantages over other species of the regenerating community. Considering that bamboo can affect the seed bank, long-term studies are needed to understand successional dynamics and evaluate suitable management actions to conserve the diversity in remaining forests.

Resumo em Inglês:

ABSTRACT The Caatinga domain is the largest and most diverse tropical semiarid ecoregion of South America; however, little is known about the diversity of desmids it harbors, especially the genus Cosmarium (Desmidiaceae, Zygnematophyceae). Our study contributes to the knowledge of Cosmarium in the Caatinga through the report of 42 interesting taxa, including a new species (Cosmarium imperiale), 22 new records for South America, and 19 additions to the desmid flora from Brazil. The samples were gathered from periphytic material from the “Pantanal dos Marimbus” in the Chapada Diamantina region of Northeast Brazil. We provide taxonomic notes, ecological information, including habitat conditions with limnological data, and updated global distributions for all taxa of Cosmarium. A complementary quantitative study was performed during the last year of sampling (2018), which revealed that most taxa have their highest densities in the months with low precipitation and when the water's conductivity and transparency are greater. Our results also have implications for the conservation of the biota from Marimbus do Baiano and understand South America's desmids' biogeography since some rare taxa identified here were previously only known from other continents such as Europe and Africa.

Resumo em Inglês:

ABSTRACT The present study analyzes the diversity of Scleria in the state of Pará and presents taxonomic treatments for all recorded species. The analysis was based on extensive herbarium studies (CEN, HBRA, HCJS, HSTM, IAN, IBGE, INPA, MFS, MG, RB, and UB) and field expeditions to several municipalities of the state of Pará. Specimens were identified using relevant literature, protologues, and type specimens available online. We recognize 30 species of Scleria arranged in two subgenera and nine sections. Four species (i.e., Scleria arguta, S. burchellii, S. longigluma, and S. vaginata) represent new records for Pará, and a new species is proposed (i.e., Scleria sp.). An identification key, descriptions, illustrations, and comments on diagnostic characters, geographic distribution and habitat for all species are also provided.

Resumo em Inglês:

ABSTRACT This synopsis presents diagnostic characters and comments on morphological variability, distribution, and conservation of species of Byttnerieae (Malvaceae, Byttnerioideae) from the Atlantic Forest. Byttnerieae is represented by species from two allied genera in this phytogeographic domain: Ayenia L. and Byttneria Loefl. An extensive literature survey along with herbarium collection analyses revealed the occurrence of 20 species in the Atlantic Forest, nine of which are endemic to Brazil. Seven species are restricted to the Southern portion of the Atlantic Forest, i.e., occurring from southern São Paulo state to the state of Santa Catarina, with most records being in Brazil, but some species also occur in Argentina and Paraguay. Beyond the Southern portion of the Atlantic Forest, three species are restricted either to the state of Rio de Janeiro or to Bahia, in Brazil. An identification key focusing on vegetative characters, as well as illustrations and notes on species distribution and conservation, are presented. Nomenclatural comments or updates for some taxa were provided, including: the designation of lectotypes for six names; the amendment of authorship of one name (B. gracilipes); and reassessment of the distribution of A. glabrescens, an endemic species of dry deciduous forests of Bahia whose precise location was unknown.

Resumo em Inglês:

ABSTRACT This study aimed to analyse the effects of invasion by the exotic Ligustrum lucidum on mycorrhizal associations in forests of Celtis tala, and to determine the role that these fungi play in the invasion process. We analyzed colonization and response to mycorrhization of both plant species under greenhouse conditions after inoculation with soil obtained from patches of non-invaded native forests and invaded forests. The spores present in pots at the end of the experiment were counted and identified. Colonization of L. lucidum was greater in plants inoculated with invaded forest soil, whereas colonization of C. tala was greater in plants inoculated with non-invaded native forest soil. Principal component analysis of fungal species abundance showed differences in AMF composition according to host plant and forest type. The results show that L. lucidum establishes symbiosis with native AMF, which triggers changes in community structure. These changes favored the mycorrhization of L. lucidum and interfered with the mycorrhization of C. tala. AMF may have either a direct or indirect role in the invasion process, not only benefiting the invasive species but also preventing the regeneration of native plants.

Resumo em Inglês:

ABSTRACT Mangaba (Hancornia speciosa) is a native fruit tree of Brazil and of great importance as an alternative source of income and subsistence for many rural communities of the Northeast region. This study aimed to identify and characterize the uses, local knowledge and management practices of H. speciosa in extrativist communities of the state of Rio Grande do Norte, Northeast Brazil. Semi-structured interviews were conducted with 59 informants. The importance of mangaba was analyzed based on the mentioned types of uses and by calculating the use diversity index and consensus value among the interviewees. Knowledge of H. speciosa is equally distributed among communities. The categories of food (0.39) and commercialization (0.37) were the most relevant use categories. No significant differences were found in the diversity of uses between genders (p>0.05, U=414), with the only differences being found between age groups, for informants over 40 years of age (IDV: p<0.05, H=25.37; IVE: p<0.05, H=24.07). Results show that the informants are dependent on the resources offered by this species, and that its importance is mainly related to the use of fruits for food and commercialization. The main form of management of mangaba was collecting the fruit, followed by promotion, tolerance, and protection.

Resumo em Inglês:

ABSTRACT Ant defense against floral enemies incurs a two-fold ant-pollinator conflict, both via pollinator deterrence and nectar or pollen collection by non-pollinating protective ants. Some ant-plants have physical barriers whereas others produce ant-repellent chemicals to avoid ant visitation to flowers and subsequent pollination interference. Passiflora coccinea is a hummingbird-pollinated myrmecophilous plant in which floral enemy repellence occurs without limiting ant access to open flowers. To test the hypothesis that ant activity is restricted within flowers to prevent contact with anthers, we compared ant defense response between reproductive (anthers and stigmas) and non-reproductive (bracts, corona and perianth) floral structures by combining an observational survey with an experimental approach. A few insect species were found to visit flowers without providing pollination service, mostly pollen-collecting bees and nectar-thieving butterflies landing on petals. Ants always attacked floral visitors that landed on non-reproductive structures, but they never attacked insects visiting reproductive structures as ants never accessed anthers. Our results suggest that the differential ant defense response is an adaptative process to prevent ant-pollinator conflict. The eventual mechanism that regulates this process could be closely linked to the corona of filaments that protects nectar chambers, simultaneously restricting ant access to nectar and pollen.

Resumo em Inglês:

ABSTRACT Intraspecific floral variations may affect the degree of generalization and efficacy of pollinators, with consequences for plant reproductive success. Such effects could be greater for heterostylous plants because morphological variation can alter reciprocity between morphs. We evaluated the frequency, composition, and efficacy of pollinators, and the reciprocity (measured by population inaccuracy) of Psychotria nuda, a distylous species of Rubiaceae, in a montane forest. Moreover, we assessed the effects of corolla length on reciprocity and reproductive success. We recorded eighteen species of floral visitors, belonging to four functional groups. The frequency of visits differed among groups with butterflies being the most frequent visitors, in contrast to hummingbird-pollinated lowland populations. This difference did not affect reproductive success, since fruit set was similar between these populations. The total population inaccuracy was 21.56 mm2, with inaccuracy of low organs being higher (12.03 mm²) than that of high organs (9.53 mm²). Floral traits may have different effects on the reproductive success of morphs of distylous species; the corolla length of P. nuda only affected the reproductive success of short-styled flowers. Large corollas showed greater reproductive success and lower individual inaccuracies for this morph, indicating compensation for the effects of imperfect reciprocal herkogamy on reproductive success.

Resumo em Inglês:

ABSTRACT Calligonum is the only C4 genus within Polygonaceae. We applied DNA sequences from the nuclear ribosomal internal transcribed spacer (nrITS) and five plastid genome regions (psbA-trnH, ycf6-psbM, trnL-F, rpl32-trnL and rbcL) to reconstruct the phylogeny of Calligonum. The nrITS and the combined plastid DNA regions were analysed separately. The phylogeny of the five plastid genome regions supports the treatment of the Calligonum mongolicum complex as a single species with intra-specific geographic structure, and suggests independent hybrid origins for the polyploid species C. caput-medusae and C. arborescens through comparisons with the nrITS tree. We detected phylogenetic incongruence between the nrITS and plastid DNA trees and hypothesized reticulate evolution or hybrid speciation in the genus. Divergence time dating based on nrITS determined that the most recent common ancestor of Calligonum species began diversification 3.46 million years ago [mya; 95 % high probability density (HPD): 1.87-5.71 mya], and diversification began in the Central Asia and China clade ca. 2.68 mya (95 % HPD: 1.28-4.59 mya). We expect that future studies employing next generation sequencing methods, such as RAD-seq, coupled with denser inter- and intra- specific taxonomic sampling, may prove to be cost-effective methods for further investigation of the evolutionary history of this genus.