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Water stress affects plant performance at various organisational levels, from morphological to molecular, with a drastic drop in crop yield. Integrative studies involving transcriptomics and physiological data in recognized tolerant species are appropriate strategies to identify and understand molecular and functional processes related to water deficit tolerance. The cashew tree (Anacardium occidentale) is a species naturally adapted to environments with low water availability associated with adverse conditions such as heat, high radiation and salinity. We used an integrative strategy, combining classical physiological measurements with high throughput RNA-seq to understand the main adaptive mechanisms of cashew to water deficit followed by recovery. Physiological analyses indicate that young cashew plants display typical isohydric behaviour. They first exhibit rapid stomatal closure, followed by CO2 assimilation, thus preserving the relative water content, membrane integrity and photosystem II activity. Differential expression was observed in 1733 genes from plant leaves exposed to water deficit stress for 26 days. Among them, 705 were upregulated and 1028 were downregulated. After rewatering, 1330 (76.7%) genes returned to their basal expression level. Transcriptional, combined with physiological data, reveal that cashew plants display high phenotypic plasticity and resilience to acute water deficit, and do not activate senescence pathways. A series of genes/pathways and processes involved with drought tolerance in cashew are evidenced, particularly in carbon metabolism, photosynthesis and chloroplast homeostasis.

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The determination of age-dated metal sediment accumulation rates in a representative South American bay is able to portray the dimension of human impacts during the colonial occupation and industrial periods. Many studies have assessed metal distribution and chronology at Guanabara Bay, in Brazil. However, understanding natural variabilities associated to paleoclimatic changes and comparing these natural variabilities to anthropogenic processes are not well established to date. Accurate geochronological control integrating ages determined by 210Pb and 14C chronologies through an exponential spline fit model allowed for a precise definition of changes associated to the holocene marine transgression, as well as the colonial period, leading to intense land use changes, and the industrial period. The reference values of the system were defined based on their concentrations and the accumulation rates of ecotoxicologically important metals. Al, Ba, Fe, Cd, Cu, Cr, Li, Ni, Mn, Pb, Si, Ti, V, and Zn distributions were determined in a Guanabara Bay core (BG-28) by the EPA 3051 method. Elemental distribution profile assessment allowed for the identification of variabilities associated to weathering processes, predominantly of lithogenic origin, mainly for Al, Ba, Fe, Li, Si, and V. Weathering processes occurred simultaneously to land use changes in the drainage basin since the colonial period, at 400 cal yr BP, and during the industrial period, mainly after the 1960s, denoted by Cd, Cr, Cu, Mn, Pb and Zn increases. The highest average metal enrichment values metals associated to industrial processes reached 5.95, with 119.1-fold higher accumulation rates than the background accumulation values observed between 4200 and 500 cal yr BP.

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This work puts forward a dynamical population model to qualitatively reproduce the phenomena of apparent competition and apparent mutualism found in an experiment with two arthropods being attacked by a predator in a context of pest biological control in greenhouse crops. The two agricultural pests consist of one species of thrips (Frankliniella occidentalis (Pergande 1895)) and one species of whiteflies (Trialeurodes vaporariorum Westwood, 1956), and the shared predator is a predatory mite (Amblyseius swirskii Athias-Herriot, 1962). The predatory mite is the biocontrol agent employed in order to achieve the biological control. The proposed model successfully reproduces this density mediated indirect interactions between pests when their carrying capacities are increased. Moreover, the pests' final population levels may depend on their initial densities and those of their predator. With these results, the proposed model may have the potential to assess whether these indirect pest interactions disrupt or enhance biological control. Additionally, it can also be used as an ancillary tool to theoretically assess the effects of pest biocontrol strategies in the referred experimental setup.

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Degradation and habitat loss of natural grasslands in Southern Brazil has a negative impact on native organisms, potentially including the composition of anuran helminth communities. Here, we characterized the richness, abundance, taxonomic composition, prevalence and intensity of helminth infection in four anuran species. Host anurans were collected in 34 ponds (19 in native grasslands with livestock and 15 in agricultural cultivation) from the highland grasslands in the Brazilian states of Santa Catarina and Paraná. Our results showed a significant difference between native grasslands with livestock and agricultural cultivation regarding the structure of helminth communities for the hosts Aplastodiscus perviridis and Pseudis cardosoi. We also found a greater prevalence and intensity of infection in anurans in areas of agricultural cultivation than in native grasslands with livestock. We found that the environmental descriptors (local and landscape) seem to explain most of the differences in anuran parasitism recorded between native grasslands with livestock and agricultural areas. Thus, we emphasized that the loss of grassy habitat due to conversion to agricultural cultivation can alter helminth communities in anurans, with further work needed to understand the mechanisms involved.

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Habitats characterized by geographic isolation such as islands have been studied using different organisms as models for understanding the dynamic and insular patterns of biodiversity. Determinants of parasite richness in insular host populations have been conducted mainly with mammals and birds, showing that parasite richness decreases in insular areas. In the present study, we predicted that the type of environment (insular or continental) can influence the richness, diversity and abundance of parasites associated with the endemic frog Haddadus binotatus (Spix, 1824). We sampled frogs in two insular and two mainland fragments to survey their helminth parasites. The total richness was composed of 15 taxa of Nematoda and two of Acanthocephala, and the community composition of the two islands had more similarities between them than the two mainland localities. The insular effect was positive for richness and abundance of helminths, and no significant effect was observed on helminth diversity - even the mean diversity presented high numbers for the islands. We presumed that insular hosts could have lost some parasites in the colonization process when these continental islands were separated from the mainland, approximately 11,000 years ago. However, the high richness and abundance on islands can be explained by an epidemiological argument, which considers high population density due to insularity and other features of the host as factors that increase parasite transmission success among individuals.

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Several factors influence the dynamics and structure of parasite communities. Our goal was to investigate how the community composition, prevalence and abundance of parasites change across seven populations of the exotic lizard Hemidactylus mabouia in Northeast Brazil, and to describe ontogenetic and sex variations. We found differences in the composition of component communities and patterns of infection according to the host body size across the lizard populations. We did not find any variation between the sexes regarding epidemiological patterns, which can probably be explained by the similar diet and habitat use of male and female H. mabouia. An unusually high abundance and prevalence of trematodes infecting this host lizard was apparent when we compared other native lizard hosts, and we suggest that local environmental conditions might be advantageous to the development and life cycle of these parasites due to the abundance of all the intermediate and definitive hosts.

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The trematodes from South American reptiles are poorly known, with only one life cycle completely characterized. We used molecular and morphological methods to characterize diplostomoid metacercariae found in 29 of 86 pointedbelly frogs, Leptodactylus podicipinus (Cope, 1862) collected in a marsh pond in Selvíria, in the central-west region of Brazil. The metacercariae were identified as Heterodiplostomum lanceolatum Dubois, 1936 (Proterodiplostomidae), a rarely reported species that matures in snakes. In phylogenetic analysis of partial sequences from 28S rDNA, H. lanceolatum fell within a polytomy with the proterodiplostomid Crocodilicola pseudostoma (molecular divergence of 4.1%) and other members of the superfamily Diplostomoidea. Our collections provide insights into the ecology of this parasite, in that infected frogs were smaller than uninfected frogs, and metacercariae were more numerous in the abdominal cavity and hindlimb muscles than in abdominal muscles, which suggests directions for future research on the transmission and pathology of this proterodiplostomid.

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Gastrointestinal nematodes can affect sheep productivity via severe weight loss, anemia and death. Infection control is generally performed with synthetic anthelmintic compounds; however, indiscriminate use of these drugs can stimulate the emergence of resistant nematodes. Thus, alternatives to the use of synthetic anthelmintic compounds have been proposed, such as the inclusion of medicinal plants in animal feed. The objective of this study was evaluate the anthelmintic activity of the leaves of the medicinal plant Psidium cattleianum Sabine (Araçá) through its hydroalcoholic extract, and using in vitro assays with the eggs and larvae of gastrointestinal nematodes obtained from naturally infected donor sheep. The extract exhibited good in vitro ovicidal and larvicidal activity, with IC50 values of 0.55 mg mL-1 for egg hatching inhibition, 0.20 mg mL-1 for larval development inhibition and an efficiency greater than 80% in the inhibition of larval migration at all concentrations evaluated (IC50 < 0.19 mg/mL). Phytochemical analysis detected higher concentrations of saponins, flavonoids, cardiac glycosides, anthraquinones and tannins in the extract. Our results demonstrated that the Psidium cattleianum Sabine’s leaves exhibit in vitro anthelmintic activity, which suggests that in addition to its other medicinal properties, this plant can help control gastrointestinal nematodes in sheep. Future in vivo assays should be performed to confirm antiparasitic efficacy.

Os nematódeos gastrintestinais podem afetar a produtividade dos ovinos por meio de perda de peso severa, anemia e morte. O controle de infecção é geralmente realizado com compostos anti-helmínticos sintéticos; entretanto, o uso indiscriminado dessas drogas pode estimular o surgimento de nematódeos resistentes. Assim, alternativas ao uso de compostos anti-helmínticos sintéticos têm sido propostas, como a inclusão de plantas medicinais na alimentação animal. O objetivo deste trabalho foi avaliar a atividade anti-helmíntica das folhas da planta medicinal Psidium cattleianum Sabine (Araçá) através de seu extrato hidroalcoólico, e utilizar ensaios in vitro com os ovos e larvas de nematódeos obtidos de ovelhas doadoras naturalmente infectadas. O extrato exibiu boa atividade ovicida e larvicida in vitro, com CI50 de 0,55 mg mL-1 para inibição da eclosão de ovos, 0,20 mg mL-1 para inibição do desenvolvimento larval e eficiência superior a 80% na inibição da migração larval em todas as concentrações avaliadas (CI50< 0,19 mg mL-1). A análise fitoquímica detectou maiores concentrações de saponinas, flavonoides, glicosídeos cardíacos, antraquinonas e taninos no extrato. Nossos resultados demonstraram que o extrato das folhas de Psidium cattleianum Sabine exibe atividade anti-helmíntica in vitro, o que sugere que, além de outras propriedades medicinais, esta planta pode ajudar no controle de nematódeos gastrintestinais em ovinos. Futuros ensaios in vivo devem ser realizados para confirmar a eficácia antiparasitária.

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Gastrointestinal nematodes can affect sheep productivity via severe weight loss, anemia and death. Infection control is generally performed with synthetic anthelmintic compounds; however, indiscriminate use of these drugs can stimulate the emergence of resistant nematodes. Thus, alternatives to the use of synthetic anthelmintic compounds have been proposed, such as the inclusion of medicinal plants in animal feed. The objective of this study was evaluate the anthelmintic activity of the leaves of the medicinal plant Psidium cattleianum Sabine (Araçá) through its hydroalcoholic extract, and using in vitro assays with the eggs and larvae of gastrointestinal nematodes obtained from naturally infected donor sheep. The extract exhibited good in vitro ovicidal and larvicidal activity, with IC50 values of 0.55 mg mL-1 for egg hatching inhibition, 0.20 mg mL-1 for larval development inhibition and an efficiency greater than 80% in the inhibition of larval migration at all concentrations evaluated (IC50 < 0.19 mg/mL). Phytochemical analysis detected higher concentrations of saponins, flavonoids, cardiac glycosides, anthraquinones and tannins in the extract. Our results demonstrated that the Psidium cattleianum Sabines leaves exhibit in vitro anthelmintic activity, which suggests that in addition to its other medicinal properties, this plant can help control gastrointestinal nematodes in sheep. Future in vivo assays should be performed to confirm antiparasitic efficacy.(AU)

Os nematódeos gastrintestinais podem afetar a produtividade dos ovinos por meio de perda de peso severa, anemia e morte. O controle de infecção é geralmente realizado com compostos anti-helmínticos sintéticos; entretanto, o uso indiscriminado dessas drogas pode estimular o surgimento de nematódeos resistentes. Assim, alternativas ao uso de compostos anti-helmínticos sintéticos têm sido propostas, como a inclusão de plantas medicinais na alimentação animal. O objetivo deste trabalho foi avaliar a atividade anti-helmíntica das folhas da planta medicinal Psidium cattleianum Sabine (Araçá) através de seu extrato hidroalcoólico, e utilizar ensaios in vitro com os ovos e larvas de nematódeos obtidos de ovelhas doadoras naturalmente infectadas. O extrato exibiu boa atividade ovicida e larvicida in vitro, com CI50 de 0,55 mg mL-1 para inibição da eclosão de ovos, 0,20 mg mL-1 para inibição do desenvolvimento larval e eficiência superior a 80% na inibição da migração larval em todas as concentrações avaliadas (CI50< 0,19 mg mL-1). A análise fitoquímica detectou maiores concentrações de saponinas, flavonoides, glicosídeos cardíacos, antraquinonas e taninos no extrato. Nossos resultados demonstraram que o extrato das folhas de Psidium cattleianum Sabine exibe atividade anti-helmíntica in vitro, o que sugere que, além de outras propriedades medicinais, esta planta pode ajudar no controle de nematódeos gastrintestinais em ovinos. Futuros ensaios in vivo devem ser realizados para confirmar a eficácia antiparasitária.(AU)

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Plant atmospheric CO2 fixation depends on the aperture of stomatal pores at the leaf epidermis. Stomatal aperture or closure is regulated by changes in the metabolism of the two surrounding guard cells, which respond directly to environmental and internal cues such as mesophyll-derived metabolites. Sucrose has been shown to play a dual role during stomatal movements. The sucrose produced in the mesophyll cells can be transported to the vicinity of the guard cells via the transpiration stream, inducing closure in periods of high photosynthetic rate. By contrast, sucrose breakdown within guard cells sustains glycolysis and glutamine biosynthesis during light-induced stomatal opening. Here, we provide an update regarding the role of sucrose in the regulation of stomatal movement highlighting recent findings from metabolic and systems biology studies. We further explore how sucrose-mediated mechanisms of stomatal movement regulation could be useful to understand evolution of stomatal physiology among different plant groups.

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BACKGROUND & AIMS: In most clinical settings basal metabolic rate (BMR) is estimated by predictive equations (PE) but there is no specific algorithm for pregnant women. To this end, this study aimed to measure BMR (BMRm) in single-fetus primigravida 63 adolescent pregnant women recruited from primary health care units from a tropical municipality in Brazil. Additionally, BMRm was compared with estimated BMR from internationally recommended PE for nonpregnant adolescents. METHODS: BMR was measured by indirect calorimetry early in the morning in the fasting pregnant adolescents in a quiet, noise and luminosity controlled room. Anthropometry was measured by conventional research protocols and pre-pregnancy anthropometry was obtained from a questionnaire. RESULTS: Mean BMRm was 5447.3 (SD, 917.3) kJ/day. The PE provided biased (overestimation of 747.2 ± 774.1 kJ/day representing 15.7 ± 17.6%) and inaccurate (approximately 40% fell within ±10% of BMRm). CONCLUSIONS: It is necessary to develop accurate estimates of BMR and energy requirements during pregnancy especially in adolescents who are still growing but already nurture a new human being.

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This study aimed to evaluate the community composition and structure of the helminths found in 13 anuran species, and to evaluate whether this parasite community is determined by anuran characteristics. We found that the helminth fauna of the amphibians from five anuran families consisted of 13 taxa and that Cosmocercidae gen. sp. was the most prevalent taxon, followed by Oswaldocruzia subauricularis. Host body size was a determining factor of the composition and structure of the parasitic fauna. Helminth abundance and richness were positively correlated with host body size. The host Leptodactylus latrans had the highest helminth richness (n = 8). The frog Hypsiboas faber had the greatest helminth diversity (H' = 0.711). The mean helminth species richness and diversity differed significantly between host species (P < 0.05). Taken together, our data indicate that, in sympatric species of amphibians, the morphological and behavioural characteristics of the hosts are important for structuring the helminth parasite communities.

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Neotropical lizards are known to harbour rich nematode parasite faunas; however, knowledge of the diversity and patterns of infection are still lacking for many species. This is true for the genus Tropidurus, in which data on patterns of parasitism are known for only approximately 11 of its 30 species. We show that the nematode fauna associated with a population of Tropidurus montanus is composed of three species of host-generalist parasites with high overall prevalence. Male and female lizards did not differ in infection pattern and there was no relationship between host body size and intensity of infection for the most prevalent parasite species. Nevertheless, overall prevalence changed seasonally, with a higher proportion of parasitized individuals being found in the dry period than in the rainy period. We discuss our findings in the context of diet patterns of T. montanus, which we suggest may explain the similarities in prevalence and intensity of infection between the sexes. In addition, seasonal changes in diet are considered to be related to the observed differences in prevalence between dry and rainy periods.

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Individual leaf area (LA) is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length L and width W) of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx) with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx) had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.(AU)

Área foliar individual (AF) é uma variável chave em estudos sobre a ecofisiologia de arbóreas, porque influencia diretamente a interceptação de luz, a fotossíntese e a evapotranspiração das árvores adultas e das mudas. Foram analisadas as dimensões foliares (comprimento - C e largura - L) de indivíduos adultos e de mudas de sete espécies arbóreas de florestas neotropicais (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera e Tabebuia stenocalyx), com o objetivo de testar a viabilidade de modelos de regressão linear para estimar a AF de indivíduos adultos e mudas. No sul da Bahia, Brasil, um primeiro conjunto de dados foi coletado entre março e outubro de 2012. A partir das sete espécies analisadas, apenas duas (P. cattleyanum e T. stenocalyx) apresentaram relações muito semelhantes entre e AF e CL, em ambos os estádios ontogenéticos. Para estas duas espécies, um segundo conjunto de dados foi coletado em agosto de 2014, a fim de validar os modelos únicos que englobam folhas de indivíduos adultos e mudas. Nossos resultados mostram a possibilidade de desenvolvimento de modelos para a predição da área foliar, abrangendo diferentes estádios ontogenéticos para espécies arbóreas tropicais. O desenvolvimento destes modelos foi mais dependente das espécies do que das diferenças entre o tamanho das folhas de mudas e de indivíduos adultos.(AU)

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Abstract Individual leaf area (LA) is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length – L and width – W) of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx) with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx) had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.

Resumo Área foliar individual (AF) é uma variável chave em estudos sobre a ecofisiologia de arbóreas, porque influencia diretamente a interceptação de luz, a fotossíntese e a evapotranspiração das árvores adultas e das mudas. Foram analisadas as dimensões foliares (comprimento - C e largura - L) de indivíduos adultos e de mudas de sete espécies arbóreas de florestas neotropicais (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera e Tabebuia stenocalyx), com o objetivo de testar a viabilidade de modelos de regressão linear para estimar a AF de indivíduos adultos e mudas. No sul da Bahia, Brasil, um primeiro conjunto de dados foi coletado entre março e outubro de 2012. A partir das sete espécies analisadas, apenas duas (P. cattleyanum e T. stenocalyx) apresentaram relações muito semelhantes entre e AF e CL, em ambos os estádios ontogenéticos. Para estas duas espécies, um segundo conjunto de dados foi coletado em agosto de 2014, a fim de validar os modelos únicos que englobam folhas de indivíduos adultos e mudas. Nossos resultados mostram a possibilidade de desenvolvimento de modelos para a predição da área foliar, abrangendo diferentes estádios ontogenéticos para espécies arbóreas tropicais. O desenvolvimento destes modelos foi mais dependente das espécies do que das diferenças entre o tamanho das folhas de mudas e de indivíduos adultos.

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Cotesia flavipes (Cameron) is a parasitoid wasp used in the biological control of the sugarcane borer (Diatraea saccharalis) (Fabr., 1794). Studies on the genetic diversity of C. flavipes are hampered by the lack of highly polymorphic molecular markers. In this report, a set of 11 microsatellite loci were developed from an enriched library of C. flavipes. Four microsatellite loci were polymorphic and were screened in 212 C. flavipes individuals (183 females and 29 males) that were randomly sampled from seven rearing laboratory populations. The number of alleles ranged from two to three. The average inbreeding coefficient (FIS) among all laboratory populations was 0.120, indicating an excess of homozygotes. The average genetic diversity within the laboratory populations was 0.292, which is lower than the values reported for wild Cotesia spp populations. Genetic diversity was most pronounced within laboratory populations (70 to 90%). Most of the observed alleles were fixed or close to fixation. This low overall genetic diversity may have originated from a founder effect, i.e., the contribution of a small number of individuals (genes and alleles) to the formation of these populations. To our knowledge, this study is the first to provide microsatellite loci and an analysis of the genetic structure of C. flavipes. Our results suggest that new introductions of C. flavipes may increase genetic diversity and improve the efficiency of the biological control of D. saccharalis. In addition, population structure data could be used to estimate the minimum number of wasps to be imported.

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Individual leaf area (LA) is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length - L and width - W) of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx) with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx) had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.

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Adults of Physalaemus cuvieri were collected and necropsied between November 2009 and January 2010. This was carried out in order to report and compare the helminth fauna associated with two populations of this anuran species from the Brazilian Atlantic rain forest under different conditions of habitat integrity. The hosts from the disturbed area were parasitized with five helminth taxa: Cosmocerca parva, Aplectana sp., Physaloptera sp., Rhabdias sp., Oswaldocruzia subauricularis (Nematoda) and Polystoma cuvieri (Monogenea) while those from the preserved area had four helminth taxa: C. parva, Aplectana sp., Physaloptera sp., Rhabdias sp., and Acanthocephalus saopaulensis (Acanthocephala). Prevalence, mean intensity of infection, mean abundance, mean richness, importance index and dominance frequency of helminth component communities were similar in both areas. The helminth community associated with anurans from the disturbed area had higher diversity than that from the preserved area. This study is the first to report on the acanthocephalan parasites of Ph. cuvieri, and the similarity between helminth fauna composition of two host populations under different selective pressures.

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This paper tested the hypothesis that the structural components of vegetation have impact over the distribution of owl species in a fragment of a semi-deciduous seasonal forest. This paper also determined which vegetation variables contributed to the spatial distribution of owl species. It was developed in the Perobas Biological Reserve (PBR) between September and December 2011. To conduct the owl census, a playback technique was applied at hearing points distributed to cover different vegetation types in the study area. A total of 56 individual owls of six species were recorded: Tropical Screech-Owl (Megascops choliba), Black-capped Screech-Owl (Megascops atricapilla), Tawny-browed Owl (Pulsatrix koeniswaldiana), Ferruginous Pygmy-Owl (Glaucidium brasilianum), Mottled Owl (Strix virgata) and Stygian Owl (Asio stygius). The results suggest that the variables of vegetation structure have impact on the occurrence of owls. The canopy height, the presence of hollow trees, fallen trees and glades are the most important structural components influencing owl distribution in the sampled area.

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Abstract This paper tested the hypothesis that the structural components of vegetation have impact over the distribution of owl species in a fragment of a semi-deciduous seasonal forest. This paper also determined which vegetation variables contributed to the spatial distribution of owl species. It was developed in the Perobas Biological Reserve (PBR) between September and December 2011. To conduct the owl census, a playback technique was applied at hearing points distributed to cover different vegetation types in the study area. A total of 56 individual owls of six species were recorded: Tropical Screech-Owl (Megascops choliba), Black-capped Screech-Owl (Megascops atricapilla), Tawny-browed Owl (Pulsatrix koeniswaldiana), Ferruginous Pygmy-Owl (Glaucidium brasilianum), Mottled Owl (Strix virgata) and Stygian Owl (Asio stygius). The results suggest that the variables of vegetation structure have impact on the occurrence of owls. The canopy height, the presence of hollow trees, fallen trees and glades are the most important structural components influencing owl distribution in the sampled area.

Resumo Este estudo testou a hipótese de que os componentes estruturais da vegetação de uma floresta influenciam a distribuição das espécies de corujas de um fragmento de floresta estacional semidecidual. O estudo também determinou quais variáveis da vegetação contribuem na distribuição espacial das espécies. O estudo foi desenvolvido na Reserva Biológica das Perobas, entre os meses de setembro e dezembro de 2011. Para realizar o censo das corujas foi utilizada a técnica de playback em pontos de escuta dispostos de modo a abranger os diferentes tipos de vegetação na área de estudo. Foi encontrado um total de 56 indivíduos de seis espécies de corujas: corujinha-do-mato (Megascops choliba), corujinha-sapo (Megascops atricapilla), murucututu-de-barriga-marela (Pulsatrix koeniswaldiana), caburé (Glaucidium brasilianum), coruja-do-mato (Strix virgata) e mocho-diabo (Asio stygius). Os resultados sugerem que as variáveis da estrutura da vegetação e composição influenciam na ocorrência de corujas. A altura do dossel, a presença de árvores ocas, árvores caídas e clareiras, demonstram que são os componentes estruturais mais influentes na distribuição de corujas na área amostrada.