Recovery of arsenic contaminated areas is a challenge society faces throughout the world. Revegetation associated with microbial activity can play an essential role in this process. This work investigated biological attributes in a gold mining area with different arsenic contents at different sites under two types of extant revegetation associated with cover layers of the soil: BS, Brachiaria sp. and Stizolobium sp., and LEGS, Acacia crassicarpa, A. holosericea, A. mangium, Sesbania virgata, Albizia lebbeck and Pseudosamanea guachapele. References were also evaluated, comprising the following three sites: B1, weathered sulfide substrate without revegetation; BM, barren material after gold extraction and PRNH (private reserve of natural heritage), an uncontaminated forest site near the mining area. The organic and microbial biomass carbon contents and substrate-induced respiration rates for these sites from highest to lowest were: PRNH > LEGS > BS > B1 and BM. These attributes were negatively correlated with soluble and total arsenic concentration in the soil. The sites that have undergone revegetation (LEGS and BS) had higher densities of bacteria, fungi, phosphate solubilizers and ammonium oxidizers than the sites without vegetation. Principal component analysis showed that the LEGS site grouped with PRNH, indicating that the use of leguminous species associated with an uncontaminated soil cover layer contributed to the improvement of the biological attributes. With the exception of acid phosphatase, all the biological attributes were indicators of soil recovery, particularly the following: microbial carbon, substrate-induced respiration, density of culturable bacteria, fungi and actinobacteria, phosphate solubilizers and metabolic quotient.
-The objective of this work was to evaluate the influence of topsoil thickness, shading and origin when performing environmental restoration in a degraded pasture area. The experiment was conducted in a randomized block design with a factorial (3 x 2 x 2) + 2 layout. Treatments consisted of combinations of topsoil origins (forest at early or middle regeneration stages), topsoil thicknesses (10, 20, or 30-cm superficial soil layer), and presence or absence of 70% shading; with two additional control treatments. Surveys on topsoil physical-chemical attributes and flora and soil coverage were conducted. Good correlation was observed between bulk density and total porosity. Vegetation comprised a total of 2,932 individuals of herbaceous, shrub and subshrub plants; 33 species in 11 families and 1 morphospecies were identified. A floristic survey of the tree stratum revealed 235 individuals belonging to 21 species and 14 families, as well as 2 unidentified species. The best natural regeneration index is observed in the 20-cm topsoil layer, where shading exerts a positive influence on the humidity and natural regeneration of the seed bank. Topsoil from middle-stage forest is the most suitable for restoration of degraded pasture areas.
Translocation of rare populations is regarded as the last resort for the conservation of species whose habitat destruction is imminent. The objective of the present study was to evaluate the effect of two height classes and three leaf reduction intensities on growth and increases in height, stem diameter, survival, and new leaf production in seedlings of Aspidosperma cylindrocarpon (peroba) obtained via rescue seedlings in a remnant of tropical semi deciduous forest. We recovered 240 individuals that were divided into two height classes (Class I-5 to 15cm and Class II-20 to 35cm) and subjected to three leaf reduction intensities (0%, 50%, and 100%), which were then transported to a shade house with 50% light reduction. Measurements of height, stem diameter, and new leaf production were collected 8 times at 0, 15, 60, 75, 90, 105, 120, and 135 days, and survival rate was measured at day 135. The average survival rate was 82.9%; 77.5% for one Class I (5-15cm) and 88.3% for Class II (20-35cm). Higher seedling growth was observed for the 0% leaf reduction treatment in both height classes. The leaves insertion were greater in the 100% cuts, with a decrease observed over time. It is advisable to restore A. cylindrocarpon seedlings in two height classes owing to the high survival rate, leaf appearance, and growth reported in the present study. The no-leaf reduction treatment (0%) is the most viable alternative for the production of A. cylindrocarpon seedlings, via rescue seedlings.
SUMMARYThe aim of this study was to evaluate the effect of the application of topsoil from a ferruginous rock field on natural regeneration and ground cover in a waste dump. To accomplish this aim, 26 plots of 1 m² and one control were installed systematically. Soil cover was estimated according to the percentage of live coverage, litter and bare soil observed in each plot. A total of 675 individuals, with 201 recorded in the first sampling and 474 in the second, were recorded. In total, 24 species and 11 families were identified, and a group of six was indeterminate, where four species were found in the first sampling and two species in the second sampling. Families with superior wealth in relation to the total were Asteraceae (26.92 %) and Melastomataceae (15.38 %); however, the families that had a higher number of individuals in the sample were Poaceae and Verbenaceae, with 33.33 % and 28.85 %, respectively. Those in the second sampling were Poaceae, Portulacaceae and Verbenaceae, with 93.03 %, 68.16 % and 35.82 %, respectively. Among the habits found, herbaceous was highlighted, with 65.63 % of the sampled individuals, followed by 6.22 % for shrubs, 5.48 % for subshrubs and 1.18 % for trees. The sterile substrate stack does not have to establish favorable conditions for vegetation because the control portion (not topsoil) filled in the two samples with 100 % bare soil.Key words: ferruginous rock field, mining, surface layer. RESUMENEl objetivo de este estudio fue evaluar el efecto de la aplicación de la capa superior del suelo del campo de roca ferruginosa sobre la regeneración natural y la cobertura del suelo en un vertedero de residuos. Para ambos se instalaron sistemáticamente 26 parcelas de 1 m² y una de control. Para la cobertura del suelo se estimó el porcentaje de cobertura viva, hojarasca y suelo desnudo observado en cada parcela. Se registraron 675 individuos, con 201 en la primera toma de muestras y 474 en la segunda. En total, se identificaron 24 especies y 11 familias, y un grupo de seis especies indeterminadas, donde se encontraron cuatro especies en la primera toma de muestras y las otras dos en la segunda. Las familias con mayor riqueza en relación con el total fueron Asteraceae (26,92 %) y Melastomataceae (15,38 %), sin embargo, las familias con mayor número de individuos fueron Poaceae y Verbenaceae en la primera muestra, con el 33,33 % y 28,85 %, respectivamente, y el segundo muestreo Poaceae, Portulacaceae y Verbenaceae con 93,03 %, 68,16 % y 35,82 %, respectivamente. Entre los hábitos que se encontraron, se destacó herbácea con 65,63 % de los individuos muestreados, seguida de 6,22 % de arbustos, 5,48 % de subarbustos y 1,18 % de árboles. El estrato de sustrato estéril no creó condiciones favorables para la vegetación, ya que la parte de control (no tierra vegetal) presentó en las dos muestras 100 % de suelo desnudo.
Introdução: As nascentes de água são consideradas os verdadeiros tesouros da propriedade rural e por isso a partir do momento em que o proprietário rural tem o sentimento de pertencimento através das ações ambientais, as intervenções e trajetória de sucesso da restauração passa a ser uma realidade. Uma realidade em que a educação ambiental entra em ação para que esse envolvimento estimule ainda mais a consciência da importância dos recursos naturais. E por isso, uma preocupação frequente quanto à preservação e qualidade de águas das nascentes desperta o interesse pela busca de ferramentas que auxiliem esse diagnóstico sem subjetividade e com assertividade. Objetivos: Assim, o objetivo deste trabalho é fazer uma revisão analítica de protocolos que têm sido utilizados na avaliação de nascentes e que podem contribuir para estudos de educação ambiental envolvendo a comunidade e até mesmo o proprietário rural afim de fazer com que o sentimento de pertencimento o estimule ainda mais nas ações de conservação dos recursos naturais. Material e métodos: As metodologias empregadas nos protocolos envolvem pontuações para cada parâmetro avaliado que somados atribuem uma nota final classificando a qualidade da água da nascente ou ainda seu grau de preservação. Resultados: Os resultados obtidos na avaliação destes diagnósticos permitem direcionar as ações de recuperação ou conservação para estas nascentes, ou ainda contribuir no monitoramento das mesmas durante a trajetória das intervenções. Conclusão: Conclui-se que são protocolos aplicáveis com sucessos nos estudos de educação ambiental e que possuem intrinsicamente os mesmos objetivos, onde alguns atrelam apenas a percepção na avaliação das nascentes, outros agregam à percepção dados de indicadores físicos, químicos e biológicos, ou ainda, uma caracterização da paisagem que circunda a nascente alvo de estudo.
The objective of this study was to test the effect of shading levels and leaf reduction intensities on the survival and growth of Copaifera langsdorffii Guillem. ex Benth., Copaifera langsdorffii Desf. and Hymenaea courbaril L. seedlings rescued from natural regeneration. Three experiments were conducted in a completely randomized design with split-plots, in which four shading composed the plots (0 or full sun; 30; 50; and 70%) and three leaf reductions intensities composed the subplots (0; 50; and 100%). General average survival after six months from the rescue was 47.6% for C. tomentosum, 44.6% for H. courbaril and 21.4% for C. langsdorffii. Considering the height, only C. tomentosum demonstrated a significant effect of leaf reduction and shading, with total or partial maintenance of leaves (0% or 50% of leaf reduction) and the when under up to 50% shading providing a greater increment. Leaf reduction is not necessary for rescuing the seedlings from H. courbaril and C. langsdorffii, whereas the leaf reduction of 50% intensity is advised to enhance the survival of C. tomentosum species. As for shading, 50% is the most suitable level for acclimatization of H. courbaril and C. tomentosum seedlings while for C. langsdorffii the level is 70%.
A avaliação do processo de sucessão vegetal em locais degradados constitui uma importante ferramenta para se definirem estratégias de recuperação. Assim, considerando-se o quadro atual de degradação nos ecossistemas florestais, o presente trabalho objetivou estudar a dinâmica da composição florística da vegetação colonizadora, em três áreas degradadas em processo de regeneração natural, na Serra do Espinhaço Meridional. No primeiro inventário, foram amostrados todos os indivíduos arbóreo-arbustivo com DAS30 ≥ 3 cm. No segundo inventário, foram registrados os indivíduos mortos, remensurados os sobreviventes e mensurados e identificados os indivíduos recrutados (DAS30 ≥ 3 cm). Foram calculadas as taxas de dinâmica: mortalidade, recrutamento, ganho e perda em área basal e número de indivíduos para cada área. Os valores de H’ obtidos para as áreas foram comparados aos pares pelo teste de t de Hutcheson. O padrão observado nas três áreas foi semelhante e as alterações mais expressivas durante os dois inventários foram o aumento significativo da densidade e o rápido aumento da área basal total. Todos os indicadores estruturais analisados mostraram que as áreas estão em processo de construção inicial, porém a área degradada pelo garimpo de ouro encontra-se em estágio sucessional mais avançado quando comparada à área degradada pelo processo de voçorocamento e à área degradada pelo garimpo de diamante.Palavras-chave: composição florística; impactos antrópicos; heterogeneidade temporal; sucessão ecológica. COLONIZING VEGETATION DYNAMICS IN THREE AREAS DEGRADED BY MININGIN SOUTHERN SERRA DO ESPINHAÇO ABSTRACT: The evaluation of the process of plant succession in degraded places is an important tool to define recovery strategies. Thus, considering the current situation of degradation in forest ecosystems, the present study aimed to study the dynamics of the floristic composition of the colonizing vegetation, in three degraded areas in the process of natural regeneration, in the Serra do Espinhaço Meridional. In the first inventory, all tree-shrub individuals with DAS30 ≥ 3 cm were sampled. In the second inventory, dead individuals were recorded, survivors were remeasured and recruited individuals were measured and identified (DAS30 ≥ 3 cm). The dynamics rates were calculated: mortality, recruitment, gain and loss in the basal area and number of individuals for each area. The H 'values obtained for the areas were compared in pairs by the Hutcheson t test. The pattern observed in the three areas was similar and the most significant changes during the two inventories were the significant increase in density and the rapid increase in the total basal area. All the structural indicators analyzed showed that the areas are in the process of initial construction, but the area degraded by gold mining is in a more advanced successional stage when compared to the area degraded by the voçorocamento process and the area degraded by diamond mining.Keywords: floristic composition; human impacts; temporal heterogeneity; ecological succession.
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