Cell wall polysaccharides from cell suspension cultures of the Atlantic Forest tree Rudgea jasminoides (Rubiaceae)

Rudgea jasminoides (Rubiaceae) is a tropical tree species native of the Atlantic Forest in the south of Brazil. Previous studies with leaf cell walls of R. jasminoides showed a different proportion of cross-linked glycans compared to what is usually reported for eudicots. However, due to the difficulties of working with whole plant organs, cell suspensions of R. jasminoides, consisting of predominantly undifferentiated cells with mainly primary cell walls, were used to examine cell walls and extracellular soluble polysaccharides (EP) released into the culture medium. Sugar composition and linkage analysis showed homogalacturonans, xylogalacturonans and arabinogalactans to be the predominant EP. In the cell wall, homogalacturonans and arabinogalactans are the major pectins, and xyloglucans and xylans are the major cross-linking glycans. The presence of xylogalacturonans in the R. jasminoides cell cultures seems to be related to the occurrence of a homogeneous cell suspension with loosely attached cells. Although all alkali extractions from the cell walls yielded amounts of xyloglucan that exceed those of the xylans, the latter was found in a proportion that is higher than what has been usually reported for primary cell walls of most eudicots. The xyloglucan from cell walls of cell suspension cultures of R. jasminoides has low fucosylation levels and high proportion of galactosyl residues, a branching pattern commonly found in storage cell-wall xyloglucans.

Lithothamnion superpositum (Corallinales; Rhodophyta): First description for the Western Atlantic or rediscovery of a species?

P>Nongeniculate Corallinaceae are poorly known in Brazil. In our endeavor to identify this group of seaweeds along the Brazilian coast we came across some specimens that fit well into the accepted circumscription of Litothamnion Heydrich. Within this genus they could be identified to what has been called L. superpositum Foslie. The specimens were represented by nongeniculate, free living specimens (rhodoliths); lumpy to fruticose growth-form, presenting flared epithallial cells in transversal section; multiporate tetrasporangial conceptacles, with roof protruding above or flush with the surrounding thallus surface; chambers 250-525 mu m in diameter and 150-230 mu m high, roof structured by filaments with 3-5 cells long; and pores in depression. Among the species described from the Brazilian coast, L. heteromorphum (Foslie) Foslie presented anatomical and reproductive characteristics similar to the referred species described from southern Africa and Australia. Therefore, we propose to consider L. heteromorphum as a heterotypic synonym of L. superpositum and extending its distribution to the Western Atlantic.

Palisada flagellifera (Ceramiales, Rhodophyta) from the Canary Islands, Spain: a new record for the eastern Atlantic Ocean based on morphological and molecular evidence

Palisada flagellifera (Ceramiales, Rhodophyta) is recorded for the first time in the eastern Atlantic Ocean off Tenerife, La Gomera, La Palma and Fuerteventura, Canary Islands, Spain. The specimens were collected in 2006-2009 growing from the lower intertidal to subtidal zones to 2 m depth at sites exposed to wave action. The species possesses a palisade-like arrangement of cortical cells in cross section, lacks secondary pit connections between them, and has tetrasporangia produced by three fertile pericentral cells (the third and the fourth additional and the second that becomes fertile), and a right-angled arrangement of tetrasporangia. Gametangia were not observed. The phylogenetic relationships were inferred by analyses of the chloroplast-encoded rbcL gene sequences from 46 taxa. The Canarian and Brazilian P. flagellifera specimens formed a highly supported clade with a low level of genetic variation in the rbcL sequences (0.02-0.04%), confirming that they are the same taxonomic entity. This study expands the geographical distribution of P. flagellifera to the eastern Atlantic Ocean.

Evidence for the conspecificity of Palisada papillosa with P. perforata (Ceramiales, Rhodophyta) from the western and eastern Atlantic Ocean on the basis of morphological and molecular analyses

Morphological and molecular studies were carried out on Palisada papillosa and P. perforata from the Canary Islands (type locality of P. perforata), Mexico and Brazil. The two species have been distinguished by features of their external morphology such as size and degree of compactness of the thalli, presence or absence of arcuate branches, branching pattern and basal system. A detailed morphological comparison between these taxa showed that none of the vegetative anatomical or reproductive characters was sufficient to separate these species. The presence or absence of cortical cells in a palisade-like arrangement, also previously used to. distinguish these species, is not applicable. The species present all characters typical of the genus, and both share production of the first pericentral cell underneath the basal cell of the trichoblast, production of two fertile pericentral cells (the second and the third additional, the first remaining sterile), spermatangial branches produced from one of two laterals on the suprabasal cell of trichoblasts, and the procarpbearing segment with four pericentral cells. Details of the procarp are described for the species for the first time. The phylogenetic position of these species was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 39 taxa, using one other Rhodomelacean taxon and two Ceramiaceae as outgroups. Relationships within the clade formed by P. papillosa and P. perforata have not been resolved due to the low level of genetic variation in their rbcL sequences (0-0.4%). Considering this and the morphological similarities, we conclude that P. papillosa is a taxonomic synonym of P. perforata. The phylogenetic analyses also supported the nomenclatural transfer of two species of Chondrophycus to Palisada, namely, P. patentiramea (Montagne) Cassano, Senties, Gil-Rodriguez & M.T. Fujii comb. nov. and P. thuyoides (Kutzing) Cassano, Senties, Gil-Rodriguez & M.T. Fujii comb. nov.

PODOCARPUS SP.PL. REFUGIA IN BRAZIL`S ATLANTIC FOREST: ANALYSING THE PAST TO IMPROVE FUTURE PROTECTION

The Atlantic rainforest has the second highest biodiversity in Brazil. It has been shrinking rapidly in area as a result of intensive deforestation, and only 7% of the original cover now remains, as isolated patches or in ecological reserves. In order to obtain new information on the distribution of the Atlantic rainforest during the Quaternary, we examined herbarium data to locate relevant populations and extracted DNA from fresh leaves from 26 populations. The present-day distribution of endemic Podocarpus populations shows that they are widely dispersed across eastern Brazil, and that the expansion of Podocarpus recorded in single Amazonian pollen records may have originated from either western or eastern populations. Genetic analysis enabled us to determine the boundaries of their regional expansion: northern and central populations of P. sellowii appeared between 5 degrees and 15 degrees S some 16,000 years ago; populations of P lambertii or sellowii have appeared between 15 degrees and 23 degrees S at different times since the last glaciation at least; and P lambertii appeared between 23 degrees and 30 degrees S during the recent expansion of Araucaria forests. The combination of botanical, pollen, and molecular analyses proved to be a rapid means of inferring distribution boundaries for sparse populations and their regional evolution within tropical ecosystems. Today the rainforest refugia we identified have become hotspots that are crucial to the survival of the Atlantic forest under unfavourable climatic conditions and, as such, offer the only possible opportunity for this type of forest to expand in the event of future climate change.

Temporal Diversity Patterns and Phenology in Fruit-feeding Butterflies in the Atlantic Forest

The Atlantic Forest deserves special attention due to its high level of species endemism and degree of threat. As in other tropical biomes, there is little information about the ecology of the organisms that occur there. The objectives of this study were to verify how fruit-feeding butterflies are distributed through time, and the relation with meteorological conditions. Species richness and Shannon index were partitioned additively at the monthly level, and beta diversity, used as a hierarchical measure of temporal species turnover, was calculated among months, trimesters, and semesters. Circular analysis was used to verify how butterflies are distributed along seasons and its relation with meteorological conditions. We sampled 6488 individuals of 73 species. Temporal diversity of butterflies was more grouped than expected by chance among the months of each trimester. Circular analyses revealed that diversity is concentrated in hot months (September-March), with the subfamily Brassolinae strongly concentrated in February-March. Average temperature was correlated with total abundance of butterflies, abundance of Biblidinae, Brassolinae and Morphinae, and richness of Satyrinae. The present results show that 3mo of sampling between September and March is enough to produce a nonbiased sample of the local assemblage of butterflies, containing at least 70 percent of the richness and 25 percent of abundance. The influence of temperature on sampling is probably related to butterfly physiology. Moreover, temperature affects resource availability for larvae and adults, which is higher in hot months. The difference in seasonality patterns among subfamilies is probably a consequence of different evolutionary pressures through time.

The matrix-tolerance hypothesis: an empirical test with frogs in the Atlantic Forest

The matrix-tolerance hypothesis suggests that the most abundant species in the inter-habitat matrix would be less vulnerable to their habitat fragmentation. This model was tested with leaf-litter frogs in the Atlantic Forest where the fragmentation process is older and more severe than in the Amazon, where the model was first developed. Frog abundance data from the agricultural matrix, forest fragments and continuous forest localities were used. We found an expected negative correlation between the abundance of frogs in the matrix and their vulnerability to fragmentation, however, results varied with fragment size and species traits. Smaller fragments exhibited stronger matrix-vulnerability correlation than intermediate fragments, while no significant relation was observed for large fragments. Moreover, some species that avoid the matrix were not sensitive to a decrease in the patch size, and the opposite was also true, indicating significant differences with that expected from the model. Most of the species that use the matrix were forest species with aquatic larvae development, but those species do not necessarily respond to fragmentation or fragment size, and thus affect more intensively the strengthen of the expected relationship. Therefore, the main relationship expected by the matrix-tolerance hypothesis was observed in the Atlantic Forest; however we noted that the prediction of this hypothesis can be substantially affected by the size of the fragments, and by species traits. We propose that matrix-tolerance model should be broadened to become a more effective model, including other patch characteristics, particularly fragment size, and individual species traits (e. g., reproductive mode and habitat preference).

Prospects for biodiversity conservation in the Atlantic Forest: Lessons from aging human-modified landscapes

Recent global assessments have shown the limited coverage of protected areas across tropical biotas, fuelling a growing interest in the potential conservation services provided by anthropogenic landscapes. Here we examine the geographic distribution of biological diversity in the Atlantic Forest of South America, synthesize the most conspicuous forest biodiversity responses to human disturbances, propose further conservation initiatives for this biota, and offer a range of general insights into the prospects of forest species persistence in human-modified tropical forest landscapes worldwide. At the biome scale, the most extensive pre-Columbian habitats across the Atlantic Forest ranged across elevations below 800 masl, which still concentrate most areas within the major centers of species endemism. Unfortunately, up to 88% of the original forest habitat has been lost, mainly across these low to intermediate elevations, whereas protected areas are clearly skewed towards high elevations above 1200 masl. At the landscape scale, most remaining Atlantic Forest cover is embedded within dynamic agro-mosaics including elements such as small forest fragments, early-to-late secondary forest patches and exotic tree mono-cultures. In this sort of aging or long-term modified landscapes, habitat fragmentation appears to effectively drive edge-dominated portions of forest fragments towards an early-successional system, greatly limiting the long-term persistence of forest-obligate and forest-dependent species. However, the extent to which forest habitats approach early-successional systems, thereby threatening the bulk of the Atlantic Forest biodiversity, depends on both past and present landscape configuration. Many elements of human-modified landscapes (e.g. patches of early-secondary forests and tree mono-cultures) may offer excellent conservation opportunities, but they cannot replace the conservation value of protected areas and hitherto unprotected large patches of old-growth forests. Finally, the biodiversity conservation services provided by anthropogenic landscapes across Atlantic Forest and other tropical forest regions can be significantly augmented by coupling biodiversity corridor initiatives with biota-scale attempts to plug existing gaps in the representativeness of protected areas. (C) 2010 Elsevier Ltd. All rights reserved.