202 research outputs found

    Terrestrial Salamander and Ant Community Responses to Imidacloprid Application in Central Appalachian Eastern Hemlock Forests

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    Imidacloprid is the most widely used insecticide in the world and has been found to impact non-target taxa in systems in which it is applied. It is used as the primary treatment method in the protection of eastern hemlocks (Tsuga canadensis) from impacts of hemlock woolly adelgid (HWA; Adelges tsugae), an invasive insect in the U.S. that is causing widespread mortality of hemlock trees. In this study, we investigated whether imidacloprid applied in eastern hemlock forests is impacting woodland salamander and ant communities. In Chapter 1, I provide an overview of the ecological importance of eastern hemlocks and the HWA invasion, with a focus on invasion and management responses in the West Virginia National Park system. I then discuss biological and ecological aspects of the pesticide imidacloprid the ecological importance of eastern hemlocks, followed by a review of potential impacts of imidacloprid on amphibians and ants. Finally, I introduce the study area, discuss research needs, and define the objectives of the thesis research. In Chapter 2, we investigated whether imidacloprid applications were associated with woodland salamander abundance and health. We sampled terrestrial salamander communities at 18 control and treatment sites, respectively, with 12–17 surveys completed at each site. We tested the influence of three imidacloprid predictors on relative abundance and body condition while accounting for influential habitat characteristics. We did not find evidence for an overall difference in relative abundance between control and treatment plots. The body condition index score of adult salamanders was negatively associated with treated tree diameter at breast height (DBH), a proxy for treatment intensity, and positively associated with years since treatment (YST) at treatment sites. Furthermore, the YST relationship was stronger at sites with greater treated tree DBH. In addition, 8 eastern red-backed salamanders (Plethodon cinereus) collected from treatment areas contained imidacloprid, indicating terrestrial salamanders are uptaking the pesticide. In Chapter 3, we investigated the influence of imidacloprid treatments in eastern hemlock forests on ant relative abundance and diversity. Using bait traps, we sampled ants at 18 control and treatment sites, respectively, in spring, summer, and fall in 2020. We captured a total of 5 species and 17,626 ants, with 10,324 ants captured in control plots and 7,302 ants captured in treatment plots. We found that relative abundance of the dominant ant species (Aphaenogaster picea) exhibited a strong negative response to imidacloprid treatments. Recovery time of the species over time was dependent on treated tree DBH and years since the plot was treated, with abundances improving faster in sites with a lower amount of treated tree DBH. We found that ant diversity was also negatively impacted by imidacloprid treatments, but the effect was weaker, with coefficient confidence intervals overlapping 0. In addition, we detected imidacloprid in the biomass of ants collected from treatment sites, indicating ants are uptaking the pesticide. Overall, our study indicates that woodland salamanders and ants in eastern hemlock forests are negatively impacted by imidacloprid treatments, but they seem to recover over time. Salamanders and ants heavily influence the ecology of forest systems in the eastern U.S. They serve as important predators and prey and can have direct and indirect influences on the biological, physical, and chemical properties of soil and vegetation. The results of this thesis may help resource managers make informed decisions to balance the need for maintaining healthy eastern hemlock forests while minimizing impacts to non-target species

    Biologia reprodutiva de Rourea induta Planch. (Connaraceae), uma espécie heterostílica de cerrado do Brasil Central.

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    (Biologia reprodutiva de Rourea induta Planch. (Connaraceae), uma espécie heterostílica de cerrado do Brasil Central). A heterostilia é um polimorfismo floral geralmente associado a sistemas genéticos de intramorfo incompatibilidade. Nós avaliamos aspectos reprodutivos da heterostilia de uma população de Rourea induta Planch. em uma área de cerrado de Brasília, DF. Foram conduzidos estudos sobre sua biologia floral, sistema reprodutivo, produção e maturação de frutos, germinação de sementes, fenologia reprodutiva e visitantes florais. As flores são pequenas (11 mm de diâmetro), com morfologia simples e possuem dois grupos de cinco estames de comprimentos diferentes e cinco pistilos. O comprimento médio de estames e pistilos diferiu significativamente entre o morfo brevistilo e o longistilo. No entanto, não houve hercogamia recíproca completa entre os dois morfos florais. Os dois morfos são intramorfo incompatíveis, mas o morfo brevistilo é completamente auto-incompatível enquanto o longistilo é parcialmente autocompatível. Apesar das diferenças na morfologia floral e no sistema reprodutivo entre os morfos, estes apresentam igual sucesso reprodutivo em condições naturais, uma vez que a produção e a maturação de frutos por planta e a taxa de germinação das sementes não diferiram significativamente. A população de R. induta apresentou floração tipo “pulsed bang” com alta sincronia intra-individual e inter-individual de floração. Grande variedade de insetos, principalmente pequenas abelhas sociais, foi observada visitando as flores. Nossos resultados sugerem que a auto-incompatibilidade parcial, a incompatibilidade intramorfo e as diferenças nas alturas dos verticilos reprodutivos entre os dois morfos reduzem os níveis de autogamia em R. induta. Em última análise, a maior produção de frutos por polinização intermorfo, promoveu a razão isoplética na população estudada e indicou que R. induta é dependente dos polinizadores para a reprodução sexuada

    Carvão pirogênico como condicionante substrato de mudas de Tachigali vulgaris L.G. Silva & H.C. Lima.

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    Este estudo teve como objetivo verificar a eficiência de carvão vegetal pirogênico como condicionante de substrato para o desenvolvimento de mudas florestais de alto vigor, testando-se o carvoeiro (Tachigali vulgaris) como espécie representativa do Bioma Cerrado. Foram tomados como modelo de produtividade os solos de elevada capacidade de troca catiônica com Horizonte A antrópico da Amazônia (Terras Pretas de Índio), ricos em carbono pirogênico derivado de carvão vegetal. O experimento foi realizado no viveiro da Universidade do Estado de Mato Grosso, no município de Nova Xavantina-MT. Foram utilizadas quatro concentrações de carvão de eucalipto (Eucalyptus sp.) com 5; 12,5; 25 e 50% do volume total do substrato base e 0% como testemunha. Foi avaliada a porcentagem de emergência no início do experimento. Durante oito meses, a cada 30 dias, foi contado o número de folhas e medida a altura total das mudas. No oitavo mês foi medido o diâmetro do coleto e determinada à massa seca da raiz e da parte aérea. Os tratamentos e a testemunha apresentaram emergência superior a 80%, não havendo influência do carvão. Entretanto, o carvão vegetal incrementou significativamente a altura das mudas, o número de folhas, o diâmetro do coleto e a massa seca radicular e da parte aérea, o que ficou evidenciado pela forte correlação positiva com as concentrações de carvão. Portanto, o carvão vegetal pirogênico é uma alternativa viável como condicionante de origem biológica do substrato para a produção de mudas potencialmente mais resistentes, requerimento importante para plantios em campo sob condições mais severas, como na recuperação de áreas degradadas no Bioma Cerrado

    Diversity, floristic composition, and structure of the woody vegetation of the Cerrado in the Cerrado–Amazon transition zone in Mato Grosso, Brazil

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s40415-015-0186-2We compared the diversity and species composition and the structure of the vegetation of three distinct Cerrado phytophysiognomies (Cerradão, Dense Cerrado, and Typical Cerrado) in the Cerrado–Amazon transition, Mato Grosso (Brazil). Species richness (observed and estimated) in the Cerradão and Dense Cerrado was higher than that recorded in the Typical Cerrado. Species diversity, based on a Rényi profile, was highest in the Dense Cerrado, in comparison with the other phytophysiognomies. We recorded a higher number of exclusive species in the Cerradão and a greater similarity (Morisita and Sørensen indices) between this vegetation type and the Dense Cerrado. While individuals were tallest in the Cerradão and Dense Cerrado and lowest in the Typical Cerrado, there was no difference among phytophysiognomies in mean diameter. A gradient in decreasing species richness and diversity (hypothesis 1) and vegetation vertical structure (hypothesis 3) was expected for the Cerradão–Dense Cerrado–Typical Cerrado; however, neither hypothesis was supported by the results. The Cerradão and Dense Cerrado were most similar in species composition not confirming hypothesis 2, which predicted that the two savanna vegetation types (Dense Cerrado and Typical Cerrado) were more similar to one another than either is to the woodland (Cerradão). Overall, the similarities among the three study communities depended on the type of parameter analyzed. While the species richness and the vertical and structure of the vegetation of the Cerradão and Dense Cerrado are closely similar, the Cerradão and Typical Cerrado are more similar in their species diversity. With regard to the floristic composition, Dense Cerrado occupies an intermediate position between Cerradão and Typical Cerrado.UNEMAT Graduate Program in Ecology and ConservationBrazilian Higher Education Training Program (CAPES)“Tropical Biomes in Transition – TROBIT”CAPES/Science without Borders ProgramPELD/CNPq (Long-Term Ecological Studies)PROCAD UnB/UNEMA

    Absorbing Roots Areas and Transpiring Leaf Areas at the Tropical Forest and Savanna Boundary in Brazil

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    © Copyright 2014 Nova Science PublishersThis is the prepublication draft of a chapter published by Nova Science Publishers in the book Savannas: Climate, Biodiversity and Ecological Significance, published in 2013. Available to purchase at https://www.novapublishers.com/catalog/product_info.php?products_id=39734TROBIT Project (Tropical Biomes in Transition

    Post-fire dynamics of woody vegetation in seasonally flooded forests (impucas) in the Cerrado-Amazonian Forest transition zone

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    Journal ArticleAuthor versions of article. The version of record is available from the publisher via doi: 10.1016/j.flora.2014.02.008© 2014 Elsevier GmbH. All rights reserved.Fire disturbance alters the structural complexity of forests, above-ground biomass stocks and patterns of growth, recruitment and mortality that determine temporal dynamics of communities. These changes may also alter forest species composition, richness, and diversity. We compared changes in plant recruitment, mortality, and turnover time over three years between burned and unburned sites of two seasonally flooded natural forest patches in a predominantly savanna landscape (regionally called 'impucas') in order to determine how fire alters forest dynamics and species composition. Within each impuca, 50 permanent plots (20m×10m) were established and all individuals ≥5cm diameter at breast height (DBH) identified and measured in two censuses, the first in 2007 and the second in 2010. Unplanned fires burned 30 plots in impuca 1 and 35 in impuca 2 after the first census, which enabled thereafter the comparison between burned and unburned sites. The highest mortality (8.0 and 24.3% year-1 for impuca 1 and 2) and turnover time (69 and 121.5 years) were observed in the burned sites, compared to 3.7 and 5.2%year-1 (mortality), and 28.4 and 40.9 years (turnover), respectively, for the unburned sites. Although these seasonally flooded impuca forests are embedded in a fire-adapted savanna landscape, the impucas vegetation appears to be sensitive to fire, with burned areas having higher mortality and turnover than unburned areas. This indicates that these forest islands are potentially at risk if regional fire frequency increases. © 2014 Elsevier GmbH.Natural Environment Research Council (NERC)Gordon and Betty Moore FoundationMato Grosso State Research Support FoundationProgram of Academic Cooperatio

    A prospective, observational cohort study of patients presenting to an emergency department with acute shoulder trauma: the Manchester emergency shoulder (MESH) project

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    Background Fracture and dislocation of the shoulder are usually identifiable through the use of plain radiographs in an emergency department. However, other significant soft tissue injuries can be missed at initial presentation. This study used contrast enhanced magnetic resonance arthrography (MRA) to determine the pattern of underlying soft tissue injuries in patients with traumatic shoulder injury, loss of active range of motion, and normal plain radiography. Methods A prospective, observational cohort study. Twenty-six patients with acute shoulder trauma and no identifiable radiograph abnormality were screened for inclusion. Those unable to actively abduction their affected arm to 90° at initial presentation and at two week’s clinical review were consented for MRA. Results Twenty patients (Mean age 44 years, 4 females) proceeded to MRA. One patient had no abnormality, three patients showed minimal pathology. Four patients had an isolated bony/labral injury. Eight patients had injuries isolated to the rotator cuff. Four patients had a combination of bony and rotator cuff injury. Four patients were referred to a specialist shoulder surgeon following MRA and underwent surgery. Conclusions Significant soft tissue pathology was common in our cohort of patients with acute shoulder trauma, despite the reassurance of normal plain radiography. These patients were unable to actively abduct to 90° both at initial presentation and at two week’s post injury review. A more aggressive management and diagnostic strategy may identify those in need of early operative intervention and provide robust rehabilitation programmes
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