Atmospheric mercury in forests: accumulation analysis in a gold mining area in the southern Amazon, Brazil.

The spatial distribution and dispersion of mercury (Hg) is associated with the structural conditions of the environment, primarily land use and vegetation cover. Man-made emissions of the metal from activities such as artisanal and small-scale gold mining (ASGM) can influence this distribution. Forest ecosystems are of particular importance as they constitute one of the most active environments in the biogeochemical cycle of Hg, and understanding these dynamics is essential to better understand its global cycle. In this study, we determined the content of Hg present in different forest strata (soil, leaf litter, herbaceous, underwood/bush, and arboreal), as well as the relationship between the presence of Hg and the landscape heterogeneity, percentage of gold mines, and ground slope. This study was carried out in tropical forest areas of the southern Brazilian Amazon. Accumulation and transport of Hg between forest strata was assessed in order to understand the influence of these forest environments on Hg accumulation in areas where ASGM occurs. We verified that there is a difference in Hg content between forest strata, indicating that atmospheric Hg is accumulated onto the arboreal stratum and transported vertically to strata below the canopy, i.e., underwood/bush and herbaceous, and subsequently accumulated in the leaf litter and transferred to the soil. Leaf litter was the stratum with the highest Hg content, characterized as a receptor for most of the Hg load from the upper strata in the forest. Therefore, it was confirmed that Hg accumulation dynamics are at play between the areas analyzed due to the proximity of ASGMs in the region. This indicates that the conservation of forest areas plays an important role in the process of atmospheric Hg deposition and accumulation, acting as a mercury sink in areas close to man-made emissions.

New records for the poorly-known monotypic genera Exallostreptus and Guaporeptus, and a list of species from Mato Grosso state, Brazil (Diplopoda: Spirostreptida: Spirostreptidae)

New records for the species Exallostreptus vanzolinii Hoffman, 1988 and Guaporeptus paradisius Hoffman, 1988, known only from the state of Rondônia, are made from the state of Mato Grosso, Brazil. Figures of gonopods, first and second leg-pair of males are provided. In addition, an updated list of 19 Spirostreptidae species from Mato Grosso is provided, with the species Plusioporus salvadorii, Trichogonostreptus (Oreastreptus) mattogrossensis, and Urostreptus tampiitauensis widely distributed in the state.

Biomass of the macrophyte remedies and detoxifies Cd(II) and Pb(II) in aqueous solution.

Aquatic plants are considered to be important remedial agents in aquatic environments contaminated by metals. The Salvinia biloba macrophyte was evaluated in relation to its removal kinetics, adsorption capacity, and toxicology, aiming at its application in the removal of Cd+2 and Pb+2 ions from aqueous solutions. A batch-type system was used, in which the plants were cultivated in microcosms containing nutritive solution and metallic ions, stored in a controlled environment (pH, temperature, and luminosity). The removal kinetics consisted in the analysis of efficiency, varying the concentrations of the metals, and time of cultivation of plants in solution. To describe the process, adsorption isotherms were constructed with the equilibrium data, which were later adjusted to Langmuir and Freundlich models. The toxicological trial was performed by sub-acute exposure test of Caenorhabditis elegans nematode to phytoremediated solutions. The results highlight the remedial effect of the plant in solutions contaminated with both metals. The kinetic study demonstrated that the plant responds differently to metals, and physical-chemical and biological processes can be attributed to the removal of metals from the solution by the plant. The equilibrium time obtained was 48 h for both metals, and the adsorption capacity was higher for Cd2+. The toxicological evaluation indicates that there was a reduction in toxicity after the remediation of the solutions by S. biloba, for all times and concentrations evaluated. Salvinia biloba was efficient for the removal of Cd2+ and Pb2+ metals from aqueous solution. The plant is a low-cost metal biosorbent and can be considered promising for phytoremediation strategies in liquid effluents and water bodies.

Assessment of the Cu(II) and Pb(II) removal efficiency of aqueous solutions by the dry biomass Aguapé: kinetics of adsorption.

Plant-based materials are promising adsorbents for treating liquid effluents. This study describes the kinetic and equilibrium parameters that best represent the copper(II) and lead(II) removal process by Eichhornia crassipes (Aguapé) dry biomass from aqueous solution, using a batch adsorption system. The plants were washed, dried, and reduced to small particles. The adsorption kinetics were assessed by varying the metal concentrations in 5, 10, and 20 mg L-1 and a control treatment (without metals) with a mixture contact time of between 5 and 720 min. Equilibrium data were fitted to the Langmuir and Freundlich models. Kinetic assay revealed fast adsorption: kinetic equilibrium was attained within 2 h with a removal efficiency of ~ 60%. The results demonstrated a fast recovery cycle of metals using the biosorbent. The biomass of E. crassipes is low cost with potential for use as a biosorbent to remove metals from solutions.

Temporal and spatial variation of Myriapoda (Diplopoda and Chilopoda) assemblages in a Neotropical floodplain / Variação temporal e espacial da assembleia de Myriapoda (Diplopoda e Chilopoda) em uma planície de inundação Neotropical

Abstract: Myriapods constitute important edaphic macrofauna taxa which dwell in different trophic levels and influence the dynamics of these environments. This study evaluated the variation in composition, richness and abundance of edaphic myriapod assemblages as a function of the distribution and structure of flooded and non-flooded habitats (spatial variation) and hydrological seasonality (temporal variation) in a floodplain of the northern Pantanal region of Mato Grosso, Brazil. Sampling was carried out in three areas of the Poconé Pantanal, along an altitudinal and inundation gradient consisting of inundated and non-inundated habitats and different vegetation formations. Three quadrats (10 x 10 m) were delimited within each habitat type, where sampling was performed using pitfall traps and mini-Winkler extractors during the dry, rising water, high water and receding water periods of two hydrological cycles within the Pantanal (2010/2011 and 2011/2012). A total of 549 millipedes were collected, consisting of 407 Diplopoda and 142 Chilopoda distributed in six orders, 12 families and 20 species. The assemblages composition varied throughout the seasonal periods, indicating that the rising water and dry periods differed from the high water and receding water periods. In addition to the variation between seasonal periods, myriapod richness and abundance also varied in relation to areas consisting of different vegetation formations. Thus, it can be concluded that the hydrological seasonality associated with the inundation gradient and different vegetation types were determinant in the heterogeneous spatial and temporal distribution of myriapod assemblages, validating that the conservation of these invertebrates in the Pantanal is directly linked to the preservation of vegetation, and consequently, ecosystem integrity.

Resumo: Os miriápodes constituem importantes táxons da macrofauna edáfica atuando em diferentes níveis tróficos, influenciando a dinâmica desses ambientes. Este estudo avaliou a variação na composição, riqueza e abundância da assembleia de miriápodes edáficos em função da distribuição e estrutura de habitats inundáveis e não inundáveis (variação espacial) e da sazonalidade hidrológica (variação temporal) em uma planície de inundação na região norte do Pantanal de Mato Grosso, Brasil. As amostragens foram realizadas em três áreas no Pantanal de Poconé, em um gradiente altitudinal e de inundação, constituídas por habitats inundáveis e não inundáveis e por diferentes formações vegetacionais. Em cada tipo de habitat foram delimitados três quadrantes (10 x 10 m), onde foram efetuadas amostragens com armadilhas pitfall e Extrator mini-Winkler, ao longo dos períodos de seca, enchente, cheia e vazante, durante dois ciclos hidrológicos do Pantanal (2010/2011 e 2011/2012). Foram amostrados 549 miriápodes, dos quais 407 Diplopoda e 142 Chilopoda, distribuídos em seis ordens, 12 famílias e 20 espécies. A composição da assembleia variou ao longo dos períodos sazonais, indicando que a enchente e seca diferem da cheia e vazante. Além da variação entre os períodos sazonais, a riqueza e abundância de miriápodes variaram também em relação às áreas, constituídas por diferentes formações vegetacionais. Assim, pode-se concluir que a sazonalidade hidrológica associada ao gradiente de inundação e os diferentes tipos vegetacionais foram determinantes para a distribuição espacial e temporal heterogênea da assembleia de miriápodes, evidenciando que a conservação destes invertebrados no Pantanal está diretamente ligada à preservação da vegetação e, consequentemente, de sua integridade ecossistêmica.

Vertical and time distribution of Pseudoscorpiones (Arthropoda: Arachnida) in a floodplain forest in the Brazilian Pantanal / Distribución vertical y temporal de Pseudoscorpiones (Arthropoda: Arachnida) en un bosque inundable del Pantanal brasileño

AbstractPseudoscorpions embrace a diverse group of arachnids with approximately 3 500 species that occur in various habitats, such as soil, leaf litter, caves and canopies. This study aimed at evaluating the relationship between the pseudoscorpion assemblages in soil, termite nests, tree trunks and canopies, as well as the temporal distribution as to the abundance and richness of species in these habitats. For this purpose different sampling techniques were applied in an integrated manner in distinct habitats of a seasonally flooded monodominant forest in the Northern Pantanal of Mato Grosso, Brazil. Data regarding the abundance and richness of assemblage species were organized by means of the Non-Metric Multidimensional Scaling (NMDS). A total of 2 068 Pseudoscorpiones distributed in seven families and 18 species were captured. Chernetidae (8 spp.) and Withiidae (5 spp.) predominated, while Atemnidae, Cheiridiidae, Geogarypidae, Lechytiidae and Olpiidae were present with only one species each. Terrestrial fauna was more abundant (1 035 ind.; 50.0 % of the total catch) with three families and 10 species. In the arboreal fauna (712 ind.; 34.4 %), four families and 13 species were found. Termite mounds (321 ind.; 15.6 %) corresponded to the habitat with the least number of individuals, however, five families and nine species were identified, including Parachernes sp. 2, Geogarypus sp. and Olpiolum sp., not found in other analyzed habitats in this forest. The analyses did not show any temporal variation as to abundance or richness of Pseudoscorpiones in each evaluated habitat; however, the analysis showed that the edaphic environment (soil + termite nests), tree trunks and tree canopies are distinct habitats in relation to the composition of the assemblage. The occurrence of typical terricolous (e.g. Parawithius sp., Withiidae gen. sp. and Parachernes sp.) and other arboricolous (e.g. Cheiridium sp., Americhernes sp. and Lustrochernes sp.) species highlights the vertical stratification of the assemblage present in this floodplain forest in the Pantanal of Mato Grosso.

ResumenLos Pseudoescorpiones comprenden un diversificado grupo de arácnidos con aproximadamente 3 500 especies que se han encontrado en varios hábitats como suelo, hojarasca, cuevas y copas de árboles. Este estudio tiene como objetivo evaluar la relación entre la comunidad de Pseudoscorpiones presentes en el suelo, nidos de termitas (termiteros), troncos y copas de árboles, así como también la distribución temporal de la abundancia y riqueza de especies en estos hábitats. Para esto, se usaron diferentes técnicas de muestreo en hábitats de un Bosque Monodominante Estacionalmente Inundado en la región norte del Pantanal, Estado Mato Grosso, Brasil. Datos referentes a abundancia y riqueza de especies del ensamble fueron ordenados por Escalamiento Multidimensional No Métrico (NMDS). Fueron capturados 2 068 Pseudoscorpiones distribuidos en siete familias y 18 especies. Chernetidae (8 spp.) y Withiidae (5 spp.) predominaron. Mientras Atemnidae, Cheiridiidae, Geogarypidae, Lechytiidae y Olpiidae fueron registradas con una especie en cada una. La fauna terrícola fue más abundante (1 035 ind.; 50.0 % de la captura total), con tres familias y 10 especies. Para la fauna arborícola (712 ind.; 34.4 %), cuatro familias y 13 especies fueron registradas. Los termiteros (321 ind.; 15.6 %) representaron el hábitat con menor número de individuos; sin embargo, fueron identificadas cinco familias y nueve especies, incluyendo Parachernes sp. 2, Geogarypus sp. y Olpiolum sp., que no se encuentra en otros hábitats analizados en este bosque. Los análisis estadísticos no evidenciaron variación temporal en la distribución de abundancia y riqueza de Pseudoscorpiones en cada hábitat evaluado; no obstante, demostraron que el ambiente edáfico (suelo y termiteros), troncos y copas de árboles son distintos en relación a la composición de la comunidad. La presencia de especies típicamente terrícolas (e.g. Parawithius sp., Withiidae gen. sp. y Parachernes sp.) y otras arborícolas (e.g. Cheiridium sp., Americhernes sp. y Lustrochernes sp.) evidencian una estratificación vertical de la comunidad de Pseudoscorpiones presente en Bosques Inundables del Pantanal brasileño.

Vertical and time distribution of Pseudoscorpiones (Arthropoda: Arachnida) in a floodplain forest in the Brazilian Pantanal

Pseudoscorpions embrace a diverse group of arachnids with approximately 3 500 species that occur in various habitats, such as soil, leaf litter, caves and canopies. This study aimed at evaluating the relationship between the pseudoscorpion assemblages in soil, termite nests, tree trunks and canopies, as well as the temporal distribution as to the abundance and richness of species in these habitats. For this purpose different sampling techniques were applied in an integrated manner in distinct habitats of a seasonally flooded monodominant forest in the Northern Pantanal of Mato Grosso, Brazil. Data regarding the abundance and richness of assemblage species were organized by means of the Non-Metric Multidimensional Scaling (NMDS). A total of 2 068 Pseudoscorpiones distributed in seven families and 18 species were captured. Chernetidae (8 spp.) and Withiidae (5 spp.) predominated, while Atemnidae, Cheiridiidae, Geogarypidae, Lechytiidae and Olpiidae were present with only one species each. Terrestrial fauna was more abundant (1 035 ind.; 50.0 % of the total catch) with three families and 10 species. In the arboreal fauna (712 ind.; 34.4 %), four families and 13 species were found. Termite mounds (321 ind.; 15.6 %) corresponded to the habitat with the least number of individuals, however, five families and nine species were identified, including Parachernes sp. 2, Geogalypus sp. and Olpiolum sp., not found in other analyzed habitats in this forest. The analyses did not show any temporal variation as to abundance or richness of Pseudoscorpiones in each evaluated habitat; however, the analysis showed that the edaphic environment (soil + termite nests), tree trunks and tree canopies are distinct habitats in relation to the composition of the assemblage. The occurrence of typical terricolous (e.g. Parawithius sp., Withiidae gen. sp. and Parachernes sp.) and other arboricolous (e.g. Cheiridium sp., Americhernes sp. and Lustrochernes sp.) species highlights the vertical stratification of the assemblage present in this floodplain forest in the Pantanal of Mato Grosso.

Predation of bat (Molossus molossus: Molossidae) by the centipede Scolopendra viridicornis (Scolopendridae) in Southern Amazonia / Predação de morcego (Molossus molossus: Molossidae) pela centopeia Scolopendra viridicornis (Scolopendridae) no sul da Amazônia

Centipedes are opportunistic carnivore predators, and large species can feed on a wide variety of vertebrates, including bats. The aim of this study was to report the third record of bat predation by centipedes worldwide, the first record in the Amazon region, while covering aspects of foraging, capture and handling of prey. We observed the occurence in a fortuitous encounter at Cristalino State Park, located in the Amazon region of the state of Mato Grosso, Brazil. The attack took place in a small wooden structure, at about three meters from the floor, and was observed for 20 minutes. During the observation, the centipede stung the neck and abdominal region of the bat several times, grabbing the prey with its 15 pairs of front legs while hanging from the ceiling with its hind legs. This type of observation suggests that vertebrates can be important preys for invertebrates such as giant centipedes, both for its nutritional composition and for the amount of energy available in a single prey.

Centopeias são predadores carnívoros oportunistas e grandes espécies podem se alimentar de uma grande variedade de vertebrados, inclusive de morcegos. O objetivo desse trabalho é reportar o terceiro registro de predação de morcego por centopeia, e o primeiro para a região Amazônica, abrangendo aspectos do forrageamento, captura e manipulação da presa. O registro foi realizado de forma fortuita, no Parque Estadual do Cristalino, região de Floresta Amazônica, no estado de Mato Grosso, Brasil. O ataque ocorreu em uma estrutura de madeira a cerca de três metros de altura e foi observado por 20 minutos. Durante a observação, a centopeia picou várias vezes o pescoço e região abdominal do morcego, agarrando a presa com seus 15 pares de pernas anteriores e se pendurando ao teto com as pernas posteriores. Esse tipo de observação sugere que vertebrados podem ser importantes presas para invertebrados, como centopeias gigantes, tanto por sua composição nutricional quanto pela quantidade de energia disponível em uma única presa.

Comunidade edáfica de Araneae (Arthropoda, Arachnida) em uma floresta sazonalmente inundável na região Norte do Pantanal de Mato Grosso, Brasil / Community of ground Araneae (Arthropoda, Arachnida) in a seasonally flooded forest in the Northern region of Pantanal of Mato Grosso, Brazil

Este estudo teve como objetivo avaliar a composição da comunidade edáfica de Araneae de uma floresta sazonalmente inundável na região norte do Pantanal de Mato Grosso, tendo como base sua densidade de atividade e emergência. Foram empregadas armadilhas de solo tipo pitfall-trap para avaliação da atividade sobre o solo, e fotoecletores de solo para verificar a densidade de emergência ao longo de todos os períodos sazonais desta região, entre janeiro de 2004 e janeiro de 2005. Como resultado obteve-se um total de 2.233 aranhas, 1.314 indivíduos obtidos com armadilhas pitfall (29 famílias e 35 gêneros) e 919 com fotoecletores de solo (27 famílias e 22 gêneros). Oonopidae (335 ind.: 15,0 por cento), Corinnidae (310 ind.; 13,9 por cento), Gnaphosidae (289 ind.; 12,9 por cento) e Ctenidae (248 ind.; 11,1 por cento) corresponderam às principais representantes desta comunidade, bem como àquelas com maior densidade de atividade sobre a superfície do solo, enquanto Salticidae (177 ind.; 19,3 por cento), Oonopidae (126 ind.; 13,7 por cento) e Gnaphosidae (114 ind.; 12,4 por cento) foram aquelas com maior densidade de emergência. Doze agrupamentos de guildas comportamentais foram identificados, sete representaram aranhas caçadoras e cinco tecelãs. As análises referentes à variação temporal da atividade e emergência desta comunidade evidenciaram que a influência de fatores abióticos como a pluviosidade e a inundação da floresta são determinantes para sua estruturação, influenciando a ocorrência de táxons como Salticidae, Corinnidae e Oonopidae.

This study aimed to evaluate the community composition of ground dwelling Araneae in a seasonally flooded forest in the Northern region of Pantanal of Mato Grosso, based on its density and emergency activity. Pitfall traps were used to estimate the ground activity and ground photoeclectors to verify the density of emergency throughout the seasonal periods between January 2004 and January 2005. A total of 2,233 spiders were collected, 1,314 with pitfall traps (29 families and 35 genera) and 919 with ground photoeclectors (27 families and 22 genera). Oonopidae (335 ind.: 15,0 percent), Corinnidae (310 ind.; 13,9 percent), Gnaphosidae (289 ind.; 12,9 percent) and Ctenidae (248 ind.; 11,1 percent) were the main representatives of the community, as well as those with higher density of activity on the soil surface, while Salticidae (177 ind.; 19,3 percent), Oonopidae (126 ind.; 13,7 percent) and Gnaphosidae (114 ind.; 12,4 percent) were those with higher density of emergency. Twelve groups of behavioral guilds were identified, seven were hunting spiders and five were weavers. The analyses concerning temporal variation of the activity and emergence of this community demonstrate that the influence of abiotic factors, such as rainfall and flooding of the forest, are determinant to its structure, influencing the occurrence of groups as Salticidae, Corinnidae and Oonopidae.

Terrestrial arthropods from tree canopies in the Pantanal of Mato Grosso, Brazil

Terrestrial arthropods from tree canopies in the Pantanal of Mato Grosso, Brazil. This study represents a contribution to the knowledge of the diversity of arthropods associated to the canopy of Vochysia divergens Pohl (Vochysiaceae). Three trees individuals were sampled during two seasonal periods in this region: a) by spraying one tree canopy during high water (February); b) by fogging two tree canopies during low water (September/October). The 15,744 arthropods (183.2±38.9 individuals/m²) obtained from all three trees (86 m²) represented 20 taxonomic orders, 87.1 percent were Insecta, and 12.9 percent Arachnida. The dominant groups were Hymenoptera (48.5 percent; 88.9 individuals/m²), mostly Formicidae (44.5 percent; 81.4 individuals/m²), followed by Coleoptera (14.0 percent; 25.5 individuals/m²) and Araneae (10.2 percent; 19.5 individuals/m²), together representing 62.5 percent of the total catch. Fourteen (70 percent) of all orders occurred on three trees. Dermaptera, Isoptera, Neuroptera, Odonata, Plecoptera and Trichoptera were collected from only one tree. Of the total, 2,197 adult Coleoptera collected (25.5±11.3 individuals/m²), 99 percent were assigned to 32 families and 256 morphospecies. Nitidulidae (17.9 percent of the total catch; 4.6 individuals/m²), Anobiidae (16.7 percent; 4.3 individuals/m²), Curculionidae (13.2 percent; 3.4 individuals/m²) and Meloidae (11.4 percent; 2.9 individuals/m²) dominated. The communitiy of adult Coleoptera on V. divergens indicated a dominance of herbivores (37.8 percent of the total catch, 127 spp.) and predators (35.2 percent, 82 spp.), followed by saprophages (16.2 percent, 32 spp.) and fungivores (10.8 percent, 15 spp.). The influence of the flood pulse on the community of arboreal arthropods in V. divergens is indicated by the seasonal variation in evaluated groups, causing changes in their structure and composition.

Artrópodes terrestres associados a copas de árvores no Pantanal de Mato Grosso, Brasil. Este estudo representa uma contribuição ao conhecimento da diversidade de artrópodes associados à copa de Vochysia divergens Pohl (Vochysiaceae). Três indivíduos foram amostrados durante dois períodos sazonais, um durante a cheia (árvore A: fevereiro) utilizando-se o método de pulverização com inseticida e dois durante a seca (árvore B: setembro, C: outubro), empregando-se a termonebulização. Um total de 15744 artrópodes (183,2±38,9 individuos/m²) foram obtidos em 86m² de área representando 20 ordens taxonômicas, 87,1 por cento Insecta e 12,9 por cento Arachnida. O grupo dominante foi Hymenoptera (48,5 por cento; 88,9 individuos/m²), a maioria Formicidae (44,5 por cento; 81,4 individuos/m²), seguido por Coleoptera (14,0 por cento; 25,5 individuos/m²) e Araneae (10,2 por cento; 19,5 individuos/m²), que representaram 62,5 por cento do total coletado. Com relação a freqüência, 14 de todas as ordens (70 por cento) ocorreram nas tres árvores. Dermaptera, Isoptera, Neuroptera, Odonata, Plecoptera e Trichoptera foram coletadas em uma única árvore. Foram obtidos 2197 Coleoptera adultos (25,5±11,3 indivíduos/m²), sendo 99 por cento assinalados para 32 famílias e 256 morfoespécies. Nitidulidae (17,9 por cento; 4,6 indivíduos/m²), Anobiidae (16,7 por cento; 4,3 indivíduos/m²), Curculionidae (13,2 por cento; 3,4 indivíduos/m²) e Meloidae (11,4 por cento; 2,9 indivíduos/m²) foram dominantes. Os Coleoptera adultos associados à copa de V. divergens indicam dominancia de herbívoros (37,8 por cento do total coletado, 127 spp.) e predadores (35,2 por cento, 82 spp.), seguidos por saprófagos (16,2 por cento, 32 spp.) e fungívoros (10,8 por cento, 15 spp.). A influência do pulso de inundação sobre a comunidade de artrópodes arbóreos associados à V. divergens é indicada pela variação sazonal nos grupos avaliados, gerando mudanças em sua estrutura e composição ao longo...

Composição da comunidade de Formicidae (Insecta, Hymenoptera) em copas de Attalea phalerata Mart. (Arecaceae), no Pantanal de Poconé, Mato Grosso, Brasil / Composition of Formicidae community (Insecta, Hymenoptera) in the canopy of Attalea phalerata Mart. (Arecaceae), in the Pantanal of PoconÚ, Mato Grosso, Brazil

Três indivíduos da palmeira Attalea phalerata Mart (Arecaceae) foram amostrados durante a fase aquática (cheia) no Pantanal de Mato Grosso (fevereiro/2001) utilizando-se a metodologia de nebulização de copas "canopy fogging". Este estudo objetivou avaliar a diversidade, hábitos alimentares e a distribuição espacial da comunidade de Formicidae em copas dessa palmeira que forma adensamentos monodominantes, típicos nessa região. Cada palmeira foi nebulizada uma única vez e realizadas três coletas subseqüentes. Um total de 966 formigas, pertencentes a 6 subfamílias, 13 tribos e 29 espécies foram amostradas em 49 m² de área amostral (19,7±52,7 indivíduos/m²) representando 3,9 por cento do total de artrópodes obtidos. Myrmicinae foi a subfamília mais representativa, com 6 tribos e 14 espécies, destacando-se Solenopsidini com 5 espécies. Formicinae foi a segunda subfamília mais abundante com 3 tribos e 8 espécies. Pheidole sp. 2 foi dominante na amostragem geral (284 indivíduos; 29,4 por cento da captura total) seguida por Camponotus (Myrmobrachys) crassus (182 individuos; 18,8 por cento) e Crematogaster (Orthocrema) sp. 1 pr. quadriformis (119 individuos; 12,3 por cento). Os índices de diversidade foram consideráveis (H'=2,185; D= 0,835) apesar de demonstrarem baixos valores de equitabilidade (0,649 e 0,248, respectivamente). Este resultado demonstra a heterogeneidade da comunidade de Formicidae associada à copa dessa palmeira. A análise da distribuição espacial desmonstrou que a maior abundância e riqueza de Formicidae ocorrem na região central da copa, próximo ao caule.

Aspectos ecológicos da comunidade de Araneae (Arthropoda, Arachnida) em copas da palmeira Attalea phalerata Mart. (Arecaceae) no Pantanal de Poconé, Mato Grosso, Brasil / Ecological aspects of a community of Araneae (Arthropoda, Arachnida) at the canopy of the palm Attalea phalerata Mart. (Arecaceae) in the Pantanal of Pocon a, Mato Grosso, Brazil

Seis palmeiras de Attalea phalerata foram amostradas durante a fase aquática (cheia) no Pantanal de Mato Grosso (fevereiro/2001), utilizando-se a metodologia de nebulização de copas "canopy fogging". Este estudo objetivou avaliar a composição, distribuição espacial, guildas comportamentais, biomassa e sazonalidade da comunidade de Araneae em copas dessa palmeira que forma adensamentos monodominantes, típicos nessa região. Um total de 1326 aranhas foram coletadas em 99 m² de área amostral (13,4 + 8,2 indivíduos/m²), representando 20 famílias, sendo Salticidae e Araneidae as mais abundantes. A biomassa total de 704 aranhas em três palmeiras correspondeu a 0.6172 mg de peso seco (0,0123+ 0,04 mg/m²). Dez guildas comportamentais demonstraram a coexistência de diferentes espécies em um mesmo habitat. Representantes de Salticidae, Oonopidae e Ctenidae dominaram entre as caçadoras, e Araneidae e Dictynidae, dentre as tecelãs. A análise de distribuição espacial demonstrou que a maior abundância de aranhas ocorreu na região central da copa, provavelmente devido à quantidade de recursos disponíveis nesse local. A comparação desses resultados com aqueles obtidos durante o período de seca, demonstra diferenças sazonais influenciadas pelo pulso de inundação, principalmente com relação à composição das famílias amostradas entre os períodos de seca e cheia.