Riqueza e Distribuição de Espécies de Borrachudos (Diptera: Simuliidae) na Região da Chapada Diamantina, BA

Taxonomically, blackflies (Simuliidae) are among the best-known aquatic insects in Brazil. However, information on their distribution is lacking for many regions. We sampled simuliids in 50 streams in the Chapada Diamantina region, State of Bahia, located in three distinct geographical areas, 20 at Lençóis, 18 at Mucugê, and 12 at Rio de Contas. We analyzed simuliid species richness and distribution in the Chapada Diamantina area as a whole, as well as in each of the three distinct geographical areas. We collected 20 species, three of which were not yet described and two were described after our sampling. The three areas are distinct in relation to environmental variables, mainly owing to differences in altitude and water pH. Four species were restricted to Rio de Contas, while four other species were restricted to Mucugê. Sixteen species were present in Mucugê and fifteen in Rio de Contas. Only twelve species were present in Lençóis, despite the higher sampling effort. Rio de Contas appears to be the area that harbors the highest species richness. Species richness was related to environmental factors only when evaluated on a small spatial scale (i.e. when each area was analyzed separately). Although we have not tested for causal relationships, our findings agree with other studies that showed that pH and altitude are important factors with which species richness and species distribution appear to be associated

Subtropical streams harbour higher genus richness and lower abundance of insects compared to boreal streams, but scale matters

Aim: Biological diversity typically varies between climatically different regions, and regions closer to the equator often support higher numbers of taxa than those closer to the poles. However, these trends have been assessed for a few organism groups, and the existing studies have rarely been based on extensive identical surveys in different climatic regions. Location: We conducted standardized surveys of wadeable streams in a boreal (western Finland) and a subtropical (south-eastern Brazil) region, sampling insects identically from 100 streams in each region and measuring the same environmental variables in both regions. Taxon: Aquatic insects. Methods: Comparisons were made at the scales of local stream sites, drainage basins and entire regions. We standardized the spatial extent of the study areas by resampling regional richness based on subsets of sites with similar extents. We examined differences in genus richness and assemblage abundance patterns between the regions using graphical and statistical modelling approaches. Results: We found that while genus accumulation and rank-abundance curves were relatively similar at the regional scale between Finland and Brazil, regional genus richness was higher in the latter but regional abundance much higher in the former region. These regional patterns for richness and abundance were reproduced by basin and local genus richness that were higher in Brazil than in Finland, and assemblage abundance that was much higher in Finland than in Brazil. The magnitude of the difference in genus richness between Brazil and Finland tended to increase from local through basin to regional scales. Main conclusions: Our findings suggest that factors related to evolutionary diversification might explain differences in genus richness between these two climatically different regions, whereas higher nutrient concentrations of stream waters might explain the higher abundance of insects in Finland than in Brazil.Peer reviewe

How far can we go in simplifying biomonitoring assessments? An integrated analysis of taxonomic surrogacy, taxonomic sufficiency and numerical resolution in a megadiverse region

The need for biodiversity conservation is increasing at a rate much faster than the acquisition of knowledge of biodiversity, such as descriptions of new species and mapping species distributions. As global changes are winning the race against the acquisition of knowledge, many researchers resort to the use of surrogate groups to aid in conservation decisions. Reductions in taxonomic and numerical resolution are also desirable, because they could allow more rapid the acquisition of knowledge while requiring less effort, if little important information is lost. In this study, we evaluated the congruence among 22 taxonomic groups sampled in a tropical forest in the Amazon basin. Our aim was to evaluate if any of these groups could be used as surrogates for the others in monitoring programs. We also evaluated if the taxonomic or numerical resolution of possible surrogates could be reduced without greatly reducing the overall congruence. Congruence among plant groups was high, whereas the congruence among most animal groups was very low, except for anurans in which congruence values were only slightly lower than for plants. Liana (Bignoniaceae) was the group with highest congruence, even using genera presence-absence data. The congruence among groups was related to environmental factors, specifically the clay and phosphorous contents of soil. Several groups showed strong spatial clumping, but this was unrelated to the congruence among groups. The high degree of congruence of lianas with the other groups suggests that it may be a reasonable surrogate group, mainly for the other plant groups analyzed, if soil data are not available. Although lianas are difficult to count and identify, the number of studies on the ecology of lianas is increasing. Most of these studies have concluded that lianas are increasing in abundance in tropical forests. In addition to the high congruence, lianas are worth monitoring in their own right because they are sensitive to global warming and the increasing frequency and severity of droughts in tropical regions. Our findings suggest that the use of data on surrogate groups with relatively low taxonomic and numerical resolutions can be a reliable shortcut for biodiversity assessments, especially in megadiverse areas with high rates of habitat conversion, where the lack of biodiversity knowledge is pervasive. (c) 2012 Elsevier Ltd. All rights reserved.PhD scholarship from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Relações espaciais e ambientais da biodiversidade em florestas tropicais

This study aimed to evaluate issues related to spatial ecology and how spatial analysis can help ecologists to understand patterns of species distribution. Initially, we reviewed the current literature on spatial ecology and illustrated basic concepts with simulated data represented various situations that ecologists frequently face. In a second step we evaluated the importance of clearly defining the spatial variables to be included in ecological models, assessing the differences between analyses using a matrix that defines dispersal routes through stream distance and routes of dispersal in a straight line overland. One of most frequently used techniques spatial ecology, spatial eigenvector functions, is generally considered to be so flexible in generating spatial patterns that it should generate the same patterns no matter what distance matrix is used. Using data from fish, aquatic insects (Trichoptera) and simulated data, we show that the technique of eigenvectors is not as flexible as expected. Therefore, the correct definition of the matrix of distances is important for an effective analysis. In the next step, we evaluated two approaches to analyze ecological data. One of them uses raw data and the other using distance matrices. A recent discussion on the use of these two approaches has been polemical and we try to clarify what types of questions each of these approaches is better able to analyze. To do this we used data on the distribution of Trichoptera in 92 streams of central Amazonia, sampled in three distinct regions (Ducke Reserve, at PDBFF areas, and at the municipality of Presidente Figueiredo). We also evaluated the effect of spatial extent and environmental heterogeneity to on the distribution of Trichoptera species. We found that environmental factors were more related to the distribution of Trichoptera than undefined factors that caused spatial clumping at all scales examined. We analyzed the distribution of anuran species at 72 sample plots in Ducke Reserve and observed that the species distribution pattern is much related to the type of reproduction of the species. The distribution of species with aquatic reproduction is better explained by environmental patterns, while species with terrestrial reproduction are better explained by spatial patterns. We conclude that anurans with aquatic reproduction are better indicated for biomonitoring and for studies evaluating the consequences of environmental disturbances than the use of species with terrestrial reproduction or than the use of both. Finally, we evaluated the congruence in the distribution patterns of 22 taxa (15 plants and 7 animal groups) sampled at Ducke reserve. We also evaluated if it is possible to reduce the taxonomic resolution of species to genera and the numeric resolution from abundance data to presence-absence data with little loss of information. Presence-absence data and genus-level identification was sufficient to capture most of the spatial patterns of most groups. There was strong congruence in the distribution pattern of plant groups, while animal groups were less concordant. Measured environmental factors were closely related to the high congruence among the groups, indicating that environment is primarily responsible for the distribution of plants in the Ducke Reserve. Although some groups showed strong spatial patterns, there was no relationship between the congruence among groups and spatial factors. The groups that were more concordant with other groups, and possible candidates as surrogates, were the lianas of the family Bignoniaceae, herbs, ferns, and trees of the families Fabaceae and Lecythidaceae.Este trabalho teve como objetivo avaliar questões referentes à ecologia espacial e como as análises espaciais podem ajudar os ecólogos a entender os padrões de distribuição de espécies. Inicialmente fizemos uma revisão da literatura mais atual sobre ecologia espacial e tentamos explicar alguns conceitos básicos através de simulação de dados para ilustrar diversas possibilidades com que os ecólogos podem se deparar. Em uma segunda etapa nós avaliamos a importância de definir bem as variáveis espaciais para serem incluídas em modelos ecológicos, avaliando a diferença entre análises usando uma matriz de distância que define rotas de dispersão pelo curso d´água e rotas de dispersão em linha reta, sobre a terra. Uma das técnicas mais recentes e utilizadas da ecologia espacial, os autovetores espaciais, podem ser tão flexíveis na geração de padrões espaciais que não importa qual matriz de distâncias é utilizada que os mesmos padrões serão gerados. Usando dados de peixes, de insetos aquáticos (Trichoptera) e dados simulados nós mostramos que a técnica de autovetores não é tão flexível como esperado. Portanto, a definição correta da matriz de distâncias é muito importante para que uma análise adequada seja feita. Em um próximo passo nós avaliamos duas abordagens para analisar dados ecológicos. Uma delas, usando dados brutos e a outra usando matrizes de distância. Uma discussão recente sobre o uso dessas duas abordagens se instalou na ecologia, porém ainda não há um consenso sobre quando usar cada uma delas. Assim, nós usamos e comparamos as duas abordagens para analisar dados de distribuição de Trichoptera em 89 riachos da Amazônia central, distribuídos em 3 regiões distintas (Reserva Ducke, áreas do PDBFF e no município de Presidente Figueiredo). Nós avaliamos o efeito da extensão espacial e da heterogeneidade ambiental nas análises da distribuição das espécies de Trichoptera. Os fatores ambientais foram os mais relacionados com a distribuição de Trichoptera em todas as escalas analisadas. Analisamos a distribuição de anuros em 72 parcelas amostrais da Reseva Ducke e observamos que o padrão de distribuição das espécies é muito relacionado ao tipo de reprodução das espécies. Espécies de anuros com reprodução aquática são mais bem explicadas por padrões ambientais enquanto as espécies com reprodução terrestre são mais explicadas por padrões espaciais. Desta forma, anuros com reprodução aquática são mais indicados para estudos de monitoramento biológico e avaliação de efeitos de alterações ambientais do que o uso de anuros com reprodução terrestre ou que o uso de ambos. Por fim, nós avaliamos a concordância nos padrões de distribuição de 22 grupos taxonômicos (15 de plantas e 7 de animais) amostrados da Reserva Ducke. Avaliamos também se é possível reduzir a resolução taxonômica de espécies para gêneros e a resolução numérica, de abundância para dados de presença e ausência sem a perda de informações importantes. Observamos que o uso de dados de presença e ausência e que identificações em nível de gênero são suficientes para analisar o padrão de distribuição dos grupos analisados. Houve grande concordância no padrão de distribuição das espécies de plantas, enquanto os grupos de animais foram pouco concordantes. Os fatores ambientais foram os mais relacionados à alta concordância entre os grupos, mostrando que o ambiente é o principal responsável pela distribuição das plantas na Reserva Ducke. Embora alguns grupos tenham apresentado forte padrão espacial não houve relação entre a concordância entre os grupos e os fatores espaciais. Os grupos mais concordantes, e possíveis candidatos a grupos substitutos, foram lianas da família Bignoniaceae, ervas, samambaias e árvores das famílias Lecythidaceae e Fabaceae