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

(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

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

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

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

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

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

© 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

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

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

Height-diameter allometry of tropical forest trees

Copyright © 2011 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/8/1081/2011/bg-8-1081-2011.html doi:10.5194/bg-8-1081-2011Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account

Bioabsorbable versus metallic interference screws for graft fixation in anterior cruciate ligament reconstruction

Background Anterior cruciate ligament (ACL) tears are frequently treated with surgical reconstruction with grafts, frequently patella tendon or hamstrings. Interference screws are often used to secure the graft in bone tunnels in the femur and tibia. This review examines whether bioabsorbable interference screws give better results than metal interference screws when used for graft fixation in ACL reconstruction. Objectives To assess the effects (benefits and harms) of bioabsorbable versus metallic interference screws for graft fixation in ACL reconstruction. Search methods We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, CENTRAL (the Cochrane Library), MEDLINE, Embase, LILACS, trial registers and reference lists of articles. Date of search: January 2016. Selection criteria We included randomised controlled trials and quasi-randomised trials comparing bioabsorbable with metallic interferences screws in ACL reconstruction. The main outcomes sought were subjective-rated knee function, failure of treatment, and activity level. Data collection and analysis At least two review authors selected eligible trials, independently assessed risk of bias, and cross-checked data. Data were pooled whenever relevant and possible. Requests for further information were sent to the original study authors. Main results We included 12 trials (11 randomised and one quasi-randomised) involving a total of 944 participants, and reporting follow-up results for 774. Participants in the 12 trials underwent ACL reconstruction with either hamstring tendon grafts (five trials) or patellar tendon grafts (seven trials). Trials participants were randomly allocated to bioabsorbable or metallic interference screws for graft fixation in both femur and tibia (seven trials)femur only (three trials)tibia only (one trial)location was not reported in the remaining trial. A variety of materials was used for the bioabsorbable screws, Poly-L-lactic acid (PLLA) being the most common. The metallic screws, where reported, were titanium. All trials were at high risk of bias, which invariably included performance bias. Seven trials were at high risk of attrition bias and eight at high risk of reporting bias. The quasi-randomised trial was assessed as being at high risk for selection bias. Based on these study limitations and insufficiency of the available data, we judged the quality of evidence for all outcomes was very low. The majority of the available data for patient-reported knee function was presented as Lysholm scores (0 to 100higher scores = better function). There was very low quality but consistent evidence of no clinically important differences between the two groups in Lysholm scores at 12 months follow-up (mean difference (MD) -0.08, 95% confidence interval (CI) -1.48 to 1.32three trials, 168 participants)24 months (MD 0.35, 95% CI -1.27 to 1.98three trials, 113 participants) or five or more years follow-up (MD 1.23, 95% CI -2.00 to 4.47two trials, 71 participants). This lack of between-group differences was also reported for Lysholm scores in several trials that did not provide sufficient data for pooling as well as for other self-reported knee function scores reported in several trials. Treatment failure was represented by the summed data for implant breakage during surgery and major postoperative complications (implant failure, graft rupture, symptomatic foreign body reactions, effusion and treated arthrofibrosis and related conditions) that were usually described in the trial reports as requiring further substantive treatment. There is very low-quality evidence of greater treatment failure in the bioabsorbable screw group (60/451 versus 29/434risk ratio (RR) 1.94 favouring metallic screw fixation, 95% CI 1.29 to 2.93885 participants, 11 studies). In a population with an assumed risk (based on the median control group risk) of 56 participants per 1000 having treatment failure after metallic screw fixation, this equates to 53 more (95% CI 17 to 108 more) per 1000 participants having treatment failure after bioabsorbable screw fixation. All 16 intraoperative complications in the bioabsorbable screw group were implant breakages upon screw insertion. Treatment failure defined as postoperative complications only still favoured the metallic screw group but the 95% CI also included the potential for a greater risk of treatment failure after metallic screw fixation: 44/451 versus 29/434RR 1.44, 95% CI 0.93 to 2.23. Based on the assumed risk of 56 participants per 1000 having postoperative treatment failure after metallic screw fixation, this equates to 25 more (95% CI 4 fewer and 69 more) per 1000 participants having this outcome after bioabsorbable screw fixation. There was very low-quality evidence of very similar activity levels in the two groups at 12 and 24 months follow-up measured via the Tegner score (0 to 10higher scores = greater activity): 12 months (MD 0.08, 95% CI -0.39 to 0.55122 participants, two studies)24 months (MD 0.01, 95% CI -0.54 to 0.5772 participants, two studies). Authors' conclusions There is very low-quality evidence of no difference in self-reported knee function and levels of activity between bioabsorbable and metallic interference screws for graft fixation in ACL reconstruction. There is very low-quality evidence that bioabsorbable screws may be associated with more overall treatment failures, including implant breakage during surgery. Further research does not appear to be a priority, but if undertaken, should also examine costs.Universidade Federal de Sao Paulo, BrazilDepartment of Orthopaedics and Traumatology, Universidade Federal de São Paulo, São Paulo, BrazilOrthopaedic and Trauma Department, Hospital Israelita Albert Einstein, São Paulo, BrazilOrthopaedic Surgery, The Ohio State University Medical Center, Columbus, OH, USADepartment of Orthopaedics and Traumatology, Universidade Federal de São Paulo, Rua Borges Lagoa, 783 - 5th Floor, São Paulo, São Paulo, 04038-032, BrazilInternal sourcesUniversidade Federal de Sao Paulo, Brazil.Web of Scienc

Structural, physiognomic and above-ground biomass variation in savanna-forest transition zones on three continents - How different are co-occurring savanna and forest formations?

Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation. Herbaceous layer cover declined as woody cover increased. This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna-forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 0.1 m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America. Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna-forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, consistent across all three continents coexistence was found to be confined to a well-defined edaphic-climate envelope with soil and climate the key determinants of the relative location of forest and savanna stands. Moreover, when considered in conjunction with the appropriate water availability metrics, it emerges that soil exchangeable cations exert considerable control on woody canopy-cover extent as measured in our pan-continental (forest + savanna) data set. Taken together these observations do not lend support to the notion of alternate stable states mediated through fire feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands

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

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

Tree height integrated into pantropical forest biomass estimates

Copyright © 2012 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/9/3381/2012/bg-9-3381-2012.htmlAboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- and Weibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (≤40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8 Mg ha−1 (range 6.6 to 112.4) to 8.0 Mg ha−1 (−2.5 to 23.0). For all plots, aboveground live biomass was −52.2 Mg ha−1 (−82.0 to −20.3 bootstrapped 95% CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass per hectare is greatest in Australia, the Guiana Shield, Asia, central and east Africa, and lowest in east-central Amazonia, W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if tropical forests span 1668 million km2 and store 285 Pg C (estimate including H), then applying our regional relationships implies that carbon storage is overestimated by 35 Pg C (31–39 bootstrapped 95% CI) if H is ignored, assuming that the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions due to deforestation