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Eschweilera tetrapetala is a tree endemic to Submontane Seasonal Forests in inland Atlantic forest areas of the Chapada Diamantina Mountains, Northeastern Brazil. The effects of climate change on the spatial distribution pattern of that species were investigated to identify priority areas for its conservation. Distribution patterns and population densities were obtained by sampling individuals in ten 200 x 10 m transects, and in thirty additional 10 x 10 m border and interior forest plots. The occurrence data were subjected to Ecological Niche Modelling using Bioclim, Maxent, and Support Vector Machine algorithms. The predicted model for the current distribution of E. tetrapetala, using the Bioclim, Maxent, and Support Vector Machine algorithms, evidenced stable areas of strong environmental suitability in the east of the Chapada Diamantina. The models also show an expansion of areas with environmental suitability during the Mid-Holocene, with retraction in the present and greater reductions predicted in future global warming scenarios. The number of individuals in the plots varied from zero to 14, indicating an aggregated distribution. Morisita’s index indicated a random distribution along a forest edge but aggregated in the forest interior. Eschweilera tetrapetala is sensitive to climatic change and anthropogenic pressure, at both regional and local scales. Resumo Eschweilera tetrapetala é uma árvore endêmica das Florestas Sazonais Submontanas (SSF) da Chapada Diamantina, remanescentes de floresta Atlântica, Brasil. Os efeitos das mudanças climáticas no padrão de distribuição espacial dessa espécie foram investigados para identificar áreas prioritárias de conservação. Os padrões de distribuição e as densidades populacionais foram obtidos por amostragem de indivíduos em dez transectos de 200 x 10 m e trinta parcelas adicionais de 10 x 10 m situadas em borda e interior de uma área da SSF. Esses dados de ocorrência foram submetidos à Modelagem de Nicho Ecológico usando os algoritmos Bioclim, Maxent e Support Vector Machine. O modelo previsto para sua distribuição atual, usando os algoritmos Bioclim, Maxent e Support Vector Machine (SVM), evidenciou áreas de forte adequabilidade ambiental a leste da Serra do Sincorá. Os modelos determinaram expansão da área de adequabilidade ambiental durante o Holoceno Médio, retração no presente e maiores reduções previstas em cenários futuros. O número de indivíduos nas parcelas variou de zero a 14, indicando distribuição agregada. O índice de Morisita indicou distribuição aleatória ao longo da borda da floresta, mas agregada no interior da floresta. Eschweilera tetrapetala é sensível às mudanças climáticas e pressão antropogênica, em escalas regional e local.

The Atlantic Forest is one of the most important biodiversity hotspots, yet only a few studies have attempted to summarize tree diversity patterns across its full extent. With the increasing availability of primary biodiversity data, such a synthesis is potentially feasible; however, a critical assessment of the available information is needed to understand the limitations of data and increase knowledge on broad-scale biodiversity patterns. Here we (i) explore the potential limitations and biases of both herbarium and inventory data, (ii) provide a synthesis of diversity patterns, and (iii) present a spatial prioritization, based on complementary scenarios, for sampling tree species across the domain. We show that despite the large amounts of herbarium data, the number of unique localities per species is rather small (median, 53) and data for most species is still scarce or not yet ready for use. The spatial patterns of both herbarium records and inventory data are influenced by the presence of protected areas, proportion of forest cover, distance to graduate programs, and variables representing ease of access. Species richness presented peaks in the mid-portion of the domain. Such a pattern is related to spatial and historical constraints, environmental variation, and influence from other phytogeographical domains.

The objective of this study was to evaluate variations in the composition and abundance of the phytoplankton community after an exceptional harmful bloom of Akashiwo sanguinea that occurred in Todos os Santos Bay (BTS) in early March, 2007. Samples were collected every ten days, between April, 2007 and March, 2008, from the estuarine gradient of the Paraguacu River to BTS. The physical and chemical variables were measured in situ using a multiparameter sensor. Water samples were collected for analysis of the dissolved inorganic nutrient concentrations and for the study of composition and abundance of the microphytoplankton. Overall, 135 taxa were identified, with a higher richness of diatoms. The total cell density ranged from 2.92 × 103 to 1.16 × 107 (5.47 × 105 ± 1.69 × 106) cells L−1, with higher values in the freshwater zone than in the marine area. Five species showed peaks of abundance throughout the study, forming small blooms. Four of these blooms occurred in the rainy season, formed by the species Guinardia striata (April, 2007), Scrippsiella cf. acuminata (August, 2007), Euglena gracilis (August, 2007), and Skeletonema cf. costatum (September, 2007), while a new bloom of the species Akashiwo sanguinea occurred during the dry season (December, 2007). The environment was typically oligotrophic, with low spatiotemporal variation in the concentrations of dissolved nutrients. Even so, we observed short-term variations in the structure and composition of the phytoplankton community, demonstrated by rapid bloom events, followed by an increase in the total abundance of microphytoplankton, especially during the rainy season. The blooms did not cause any notable changes in the water column and did not present any harmful effects on the system.

The increasing worldwide interest on the conservation of tropical forests reflects the conversion of over 50% of their area into agricultural lands and other uses. Understanding the distribution of remaining biodiversity across agricultural landscapes is an essential task to guide future conservation strategies. To understand the long-term effects of fragmentation on biodiversity, we investigated whether forest fragments in southeastern Brazil are under a taxonomic homogenization or heterogenization process. We estimated pre-deforestation species richness and composition based on a Species Distribution Modelling approach, and compared them to the observed patterns of α- and β-diversity. In particular, we asked (i) if changes in β-diversity reveal convergence or divergence on species composition; (ii) if these changes are similar between forest fragments in Strictly Protected Areas (SPAs) (n=20) and within private lands (n=367) and in different regions of the state (West, Center, and Southeast). We detected steep reductions in observed local species richness in relation to our modeled predictions, and this was particularly true among forest fragments in non-protected private lands. The higher observed β diversity indicated an overall biotic heterogenization process, consistent with the idea that the originally diverse vegetation is now reduced to small and isolated patches, with unique disturbance histories and impoverished communities derived from a large regional species pool. Since conservation of biodiversity extends beyond the boundaries of strictly Protected Areas, we advocate forest fragments are valuable for conservation in agricultural landscapes, with particular relevance for private lands, which represent the most exposed and neglected share of what is left.

Benthic diatoms that produce and live inside mucilage tubes are prominent pioneer colonizers of marine substrata. This adaptation is an ecological strategy related to mechanical protection against wave action and desiccation. In this article, we identify Nitzschia martiana based on morphological and ultrastructural analyses from several samples, collected from different localities. We also analysed the potential distribution model of the species to identify potential areas along the Brazilian coast with high environmental suitability for its occurrence. The distribution modelling, associated with our wide sampling, allowed us to present a robust characterization of the distribution of N. martiana along the Brazilian coast. Previous records were restricted to the coast of the states of Paraná, Santa Catarina, and Pernambuco. Our results confirmed the occurrence of the species in 14 new localities, over a temperature range of 18–27°C, always occurring as macroscopic tufts, in regions exposed to direct sunlight during low tide periods, on sand, coral reefs and rocks.

A Floresta Atlântica apresenta padrões de heterogeneidade ainda pouco conhecidos, em especial aqueles associados à altitude, raramente investigados no eixo setentrional brasileiro. O objetivo do presente trabalho foi verificar a ocorrência de variações na composição florística, diversidade e estrutura da vegetação num remanescente de floresta Montana no sul da Bahia, através da análise de dois trechos de vegetação em diferentes altitudes. Foram amostrados no total 0,5 ha através de cinco plots separados entre si e alocados numa floresta úmida na RPPN Serra Bonita, Bahia, Brasil. Registraram-se 354 espécies de 68 famílias, sendo Myrtaceae, Fabaceae, Rubiaceae e Lauraceae as mais ricas. Os dois trechos apresentaram diferenças em densidade, área basal e estrutura, percebendo-se que com o aumento da altitude, ocorre uma diminuição no porte da floresta, refletindo maior densidade no sub-bosque, além de redução na riqueza específica. A Serra Bonita apresentou alta diversidade, similar a outras áreas na Bahia, porém maior que na Floresta Atlântica no sudeste do Brasil. Os trechos amostrados apresentaram bom estado de conservação, com abundância de lianas lenhosas, elevada área basal e baixa evidência de extração madeireira. As variações detectadas entre os trechos inventariados sugerem modificações estruturais abruptas, influenciadas possivelmente por precipitação, temperatura e barreiras locais determinadas por uma topografia acidentada, mas não por fatores edáficos.