Direct and indirect effects of geographic and environmental factors on ant beta diversity across Amazon basin.

Understanding the direct and indirect effects of niche and neutral processes in structuring species diversity is particularly challenging because environmental factors are often geographically structured. Here, we used Structural Equation Modeling to quantify direct and indirect effects of geographic distance, the Amazon River's opposite margins, and environmental differences in temperature, precipitation, and vegetation density (Normalized Difference Vegetation Index-NDVI) on ant beta diversity (Jaccard's dissimilarity) across Amazon basin. We used a comprehensive survey of ground-dwelling ant species from 126 plots distributed across eight sampling sites along a broad environmental gradient. We found that geographic distance and NDVI differences were the major direct predictors of ant composition dissimilarity. The major indirect effect was that of temperature through NDVI, whereas precipitation neither had direct or indirect detectable effects on beta diversity. Thus, ant compositional dissimilarity seems to be mainly driven by a combination of isolation by distance (through dispersal limitation) and selection imposed by vegetation density, and indirectly, by temperature. Our results suggest that neutral and niche processes have been similarly crucial in driving the current beta diversity patterns of Amazonian ground-dwelling ants.

Ants of the State of Par, Brazil: a historical and comprehensive dataset of a key biodiversity hotspot in the Amazon Basin.

The state of Par in northern Brazil is located entirely within the Amazon Basin and harbors a great diversity of landscape and vegetation types that support high levels of biodiversity. Here, we provide a comprehensive inventory of ant species and their distribution in Par. This regional list is based on an extensive review of species records from published and unpublished sources covering a period of 134 years (18862020) and includes the five most representative ant collections in Brazil. In total, we documented 12 subfamilies, 90 genera and 753 ant species, including 97 species recorded for the first time in Par and 12 species newly reported in Brazil. Sampling effort across the state is highly uneven, and most records may be associated with research areas near the state capital, mining areas, hydroelectric dams, and research field stations run by the state or universities. In addition, our results suggest a strong bias in ant collection in Par in terms of proximity of sampled sites to access routes, such as roads and rivers. We also found that species records were highly unevenly distributed based on areas of endemism within the Amazon, vegetation type, and protected areas within the state. Ant surveys are still lacking from most protected areas of Par, and further sampling is urgently needed in view of the current trend of expansion of major infrastructure projects and natural resource harvesting within protected areas of Par. Our database represents an extremely valuable and rich source of information for further studies on ant biodiversity and conservation in the Amazon Basin.

Species diversity of edaphic mites (Acari: Oribatida) and effects of topography, soil properties and litter gradients on their qualitative and quantitative composition in 64 km² of forest in Amazonia.

Small-scale spatial distribution of oribatid mites has been investigated in Amazonia. In addition, medium- and large-scale studies are needed to establish the utility of these mites in detecting natural environmental variability, and to distinguish this variability from anthropogenic impacts. We are expanding the knowledge about oribatid mites in a wet upland forest reserve, and investigate whether a standardized and integrated protocol is an efficient way to assess the effects of environmental variables on their qualitative and quantitative composition on a large spatial scale inside an ecological reserve in Central Amazonia, Brazil. Samples for Berlese-Tullgren extraction were taken in 72 plots of 250 × 6 m distributed over 64 km(2). In total 3,182 adult individuals, from 82 species and 79 morphospecies were recorded, expanding the number of species known in the reserve from 149 to 254. Galumna, Rostrozetes and Scheloribates were the most speciose genera, and 57 species were rare. Rostrozetes ovulum, Pergalumna passimpuctata and Archegozetes longisetosus were the most abundant species, and the first two were the most frequent. Species number and abundance were not correlated with clay content, slope, pH and litter quantity. However, Principal Coordinate Analysis indicated that as the percentage of clay content, litter quantity and pH changed, the oribatid mite qualitative and quantitative composition also changed. The standardized protocol effectively captured the diversity, as we collected one of the largest registers of oribatid mites' species for Amazonia. Moreover, biological and ecological data were integrated to capture the effects of environmental variables accounting for their diversity and abundance.

Diversidade de espécies dos gêneros de Crematogaster, Gnamptogenys e Pachycondyla (Hymenoptera: Formicidae) e complementaridade dos métodos de coleta durante a estação seca numa estação ecológica no estado do Pará, Brasil / Diversity of species of the genera Crematogaster,Gnamptogenys and Pachycondyla, (Hymenoptera: Formicidae) and complementarity of sampling methods during the dry season in an ecological station in the Brazilian state of Pará

As formigas são muito usadas em programas de inventários e monitoramentos, resultando em grande quantidade de material coletado com vários métodos, limitações financeiras e na falta de taxonomos para vários táxons. Para contribuir na elaboração de protocolos alternativos, analisamos a complementaridade de dois métodos de amostragem na detecção da riqueza de espécies. Em seis parcelas de 1 km² distribuídas em 33.000 ha de floresta primária, investigamos a diversidade e a freqüência das espécies de Crematogaster,Gnamptogenys e Pachycondyla, como parte do protocolo de formigas de serapilheira do Projeto TEAM. Em cada parcela, quatro transectos de 100 m foram instalados. Dez sub-amostras foram efetuadas por transecto, usando extrator de Winkler e armadilha de fosso. Registramos 36 espécies, sendo 15 novos registros para o Pará e 29 para a área de estudo. Dezessete espécies foram comuns aos dois métodos, onze foram capturadas com armadilhas de fosso e oito com Winkler. As proporções de espécies representadas por um indivíduo ("singletons") foram altas para ambos os métodos (> 0,4). Dezenove espécies foram coletadas por apenas um método e três foram representadas por apenas um indivíduo em cada método. A análise de ordenação (escalonamento multidimensional semi-híbrido) revelou diferenças na estrutura das comunidades de formigas obtidas pelos dois métodos de amostragem. Houve um efeito de complementaridade entre os dois métodos para a obtenção de um levantamento mais completo da riqueza de espécies, significando que ambos devem ser usados no protocolo. Outros recursos, como a rarefação e/ou diluição das amostras são recursos a serem avaliados em futuras investigações.

Ants are largely used for monitoring and inventory programs, resulting in great amounts of material sampled with several methodologies, financial limitations and lack of experts to do the taxonomy of many taxa. To contribute for the elaboration of alternative protocols, we analyzed the complementarity of two sampling methods in the detection of species richness. In 6 plots of 1 km² distributed in an area of 33,000 ha of continuous primary forest, in the Brazilian state of Pará, the diversity and the frequency of species of genera Crematogaster,Gnamptogenys and Pachycondyla were investigated, as part of the "Ant methodology Protocol" of the Project TEAM. Using the Winkler extractor and pitfall traps, 10 sub-samples were collected per transect. In each plot, 4 transects of 100 m were installed. We registered 36 species, and 15 are new records for the state, and 29 for the study site. Seventeen species were common to both sampling methods, 11 were captured with pitfall and 8 with Winkler. The proportions of singletons were high for both methods (>0,4). Nineteen species were captured by only one method and three were represented by only one individual in both methods. Ordination analysis (SSH, Semi-Strong Hybrid Multi-Dimensional Scaling) indicated differences in community structure between both sampling methods. There was a complementarity's effect between these two methods in order to obtain a more complete inventory of the species richness, indicating that both must be used in the protocol. Other resources like rarefaction and/or sample dilution must be evaluated in future investigations.