30 research outputs found

    Macro-scale (biomes) differences in neotropical stream processes and community structure

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    The definition of conservation strategies and ecological assessment schemes requires understanding ecosystem patterns over multiple spatial scales. This study aimed to determine if macro-scale structural and functional (processes) patterns associated with stream ecosystems differed among three neotropical biomes (Cerrado, Amazon, Atlantic Forest). We compared the aquatic communities (benthic invertebrates and hyphomycetes) and processes (decomposition rates, primary production and biofilms growth and aquatic hyphomycetes reproduction rates-sporulation) of Cerrado stream sites (neotropical savannah) against those of stream sites in the connecting biomes of the Atlantic Forest and Amazon (rainforests). We expected that, contrary to the biome dependency hypothesis the community structure and processes rates of streams at the biome-scale would not differ significantly, because those ecosystems are strongly influenced by their dense riparian forests, which have a transitional character among the three biomes. Fifty-three stream sites were selected covering a wide range of geographic locations (Table 1), from near the Equator (2° S) in the Amazon, to intermediate latitudes in the Cerrado (12-19° S), and latitudes closer to the tropic of Capricorn in the Atlantic Forest (19º-25° S). We found that: 1) at the abiotic level, the aquatic ecosystems of the three biomes differed, which was mostly explained by large-scale factors such as temperature, precipitation and altitude; 2) functional and structural variables did not behave similarly among biomes: decomposition and sporulation rates showed larger differences among biomes than invertebrate and aquatic hyphomycete assemblages structure; 3) invertebrate assemblages structure differed between the rainforests and Cerrado but not between rainforests (Amazon and Atlantic Forest) whereas aquatic hyphomycetes were similar among all biomes; 4) biofilm growth and algae concentration in biofilms of artificial substrates were highly variable within biomes and not significantly different between biomes. Overall, aquatic ecosystem processes and community structure differed across biomes, being influenced by climatic variables, but the variation is not as pronounced as that described for terrestrial systems. Considering the potential use of these functional and structural indicators in national-wide ecological assessments, our results indicate the need to define different reference values for different biomes, depending on the variable used. The approach followed in this study allowed an integrative analysis and comparison of the stream ecosystems across three tropical biomes, being the first study of this kind. Future studies should try to confirm the patterns evidenced here with more sites from other areas of the three biomes, and especially from the Amazon, which was the least represented biome in our investigation. © 201

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding 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,5–7 vast areas of the tropics remain understudied.8–11 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 underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities 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 or ganism 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 ne glected 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 lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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    Pervasive gaps in Amazonian ecological research

    Get PDF
    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

    Uma nova espécie de Notalina Mosely, 1936 (Trichoptera: Leptoceridae) proveniente do Parque Nacional da Chapada dos Veadeiros, Goiás, Brasil

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    The endemic Neotropical long-horned caddisfly subgenus Notalina (Neonotalina) Holzenthal contains nine described species in two species groups, the brasiliana and roraima groups, from the Brazilian Southeastern and Amazonian regions, respectively. In this paper, a new species of Notalina in the brasiliana species group, from Chapada dos Veadeiros National Park, Goiás state, Brazil, is described and illustrated. The new species is easily recognized by the following character set: presence of two pairs of processes on abdominal segment X; presence of well-developed basoventral protuberances, mesally directed in ventral view; presence of triangle-shaped, acuminated mesoventral process on the inferior appendages; and phallic apparatus with flanges slightly curved in dorsal view, not laterally directed.O subgênero neotropical Notalina (Neonotalina) Holzenthal contém nove espécies descritas em dois grupos de espécies, brasiliana e roraima, provenientes do Sudeste brasileiro e da região Amazônica, respectivamente. Neste artigo, uma nova espécie de Notalina é descrita e ilustrada a partir de espécimes colecionados no Parque Nacional da Chapada dos Veadeiros, Goiás, Brasil. A nova espécie é facilmente diagnosticada pelo seguinte conjunto de caracteres: presença de dois pares de processos no segmento abdominal X; presença de protuberâncias basoventrais bem desenvolvidas, mesalmente direcionadas em vista ventral; presença de processo mesoventral acuminado, com formato triangular no apêndice inferior, e aparato fálico com extensões laterais levemente curvadas em vista dorsal, não direcionadas lateralmente

    Considerações acerca da filogenia de Trichoptera Kirby 1813: da análise dos dados para as hipóteses ou dos cenários para os dados

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    Trichoptera are the major order among the aquatic insects and constitute a large proportion of benthic macroinvertebrate community. There are about 13000 described species of caddisflies in the world from freshwater ecosystems, and some marine species of Chathamiidae from New Zealand and Australia. In the last 40 years, several different hypotheses of Trichoptera�s phylogeny have been proposed, some analyses with reduced taxon sampling (other analyses with more complete data basis), some analyses with character polarization based in a priori evolutionary scenarios (other with more objective methods), some analyses using only morphological data (other using different data sources as morphology, molecular, ethological data), and some proposals from analyses using maximum parsimony or using Bayesian algorithms. The aim of this paper is integrate the taxonomical knowledge of phylogeny of Trichoptera to building an elucidative landscape and, consequently, to frame the conceptual structure to the development of the future phylogenetic works on Trichoptera systematics.Trichoptera compreendem a maior ordem de insetos estritamente aquáticos e constitui a maior proporção da comunidade dos macroinvertebrados bentônicos, com uma fauna mundial em torno de 13.000 espécies descritas para os ecossistemas dulcícolas, além de algumas espécies marinhas da família Chathamiidae, encontradas na Nova Zelândia e Austrália. Nos últimos 40 anos, várias hipóteses da filogenia de Trichoptera têm sido propostas, algumas com amostragens taxonômicas bastante restritas (outras mais completas), algumas com polarização dos caracteres baseada em cenários evolutivos pré-estabelecidos (outras com métodos mais objetivos), algumas apenas com dados morfológicos (outras utilizando dados de diferentes fontes, como morfológicos, moleculares, etológicos) e, por fim, algumas propostas oriundas de análises utilizando máxima parcimônia ou algoritmos bayesianos. O objetivo deste artigo é integrar o conhecimento acerca da filogenia de Trichoptera a fim de construir um panorama elucidativo da atual situação deste táxon e, conseqüentemente, fornecer a estrutura conceitual para o desenvolvimento de trabalhos futuros acerca da filogenia de Trichoptera
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