Andropogon Bicornis Research Articles

Phytosociological Survey of Weeds on Degraded and Well-Managed Pastures: Agronomical and Ecological Implications

The objective of this research was to carry out a survey of weeds in pastures in the Middle Valley of Paraíba do Sul, Rio de Janeiro State, Brazil, in order to subsidize weed management and pasture recovery. Weed identification and plant count were carried out in pastures with four levels of degradation, classified as low (N1), moderate (N2), strong (N3) and very strong (N4), with five replications. Thirty-nine weed species were identified and distributed into16 botanical families. Poaceae, Asteraceae and Fabaceae were the most relevant families. The number and density of weeds increased as the level of degradation decreased. The relative importance of weed species varied with the level of degraded pasture. The main weeds found in N1 were Melinis minutiflora, Desmodium incanum, Croton lundianus, Andropogon bicornis, and Imperata brasiliensis; in N2: Paspalum notatum, Melinis minutiflora, Imperata brasiliensis, Sida rhombifolia, and Desmodium incanum; in N3: Paspalum notatum, Melinis minutiflora, Sida rhombifolia, Eupatorium maximilianii, and Imperata brasiliensis; in N4: Paspalum notatum, Melinis minutiflora, Cynodon dactilon, Eupatorium maximilianii, and Imperata brasiliensis. The similarity index was high, showing the homogeneity of weeds among areas. The predominant species, considering all areas, were in increasing order of importance: Cynodon dactilon, Melinis minutiflora and Paspalum notatum. Decision-making about applying control measures could be marked out when the plant density reached out or exceed the average of 3.58 plants m-2.

Seed Rain in a Degraded Mining Area: The Role of Bird Perches and Pioneer Trees

Mining causes changes in natural areas, from the elimination of vegetation and the seed bank to physical changes in the soil and water dynamics. The recovery of such impacted areas depends on both the natural process of secondary succession and the use of techniques that assist the return of the flora. Aiming to evaluate the seed rain in an area of basaltic rock mining, 18 seed collectors of 0.5 m2 were installed placed under artificial perches, pioneer trees (natural perches) and control collectors. After 12 months, 8976 seeds of 33 plant species were quantified with an average density of 997 seeds m2 year-1 that differed statistically between the different perches. Artificial perches were more efficient in facilitating the seed rain, the most abundant of which were Cecropia pachystachya Trécul (n=3218), Andropogon bicornis L. (n=1417), Urochloa plantaginea (Link) R.D.Webster (n=1179), and Leucaena leucocephala (Lam.) de Wit (n=1138) were more abundant and represented 77.4% of total collected seeds and 12.1% of species richness. The installation of artificial perches should be encouraged in degraded areas, because they facilitate the visitation of birds and seed dispersal, contributing both to the arrival of seeds and to an increase in seed richness in the area.

Population density, spatial patterns and sample size of Edessa meditabunda (F., 1794) (Hemiptera: Pentatomidae) on alternative plants during soybean off-season in southern Brazil

Edessa meditabunda (F., 1794) (Hemiptera: Pentatomidae) is considered a potential pest for soybean crops in the Neotropical region. During winter (i.e. the soybean off-season), the stink bugs seek alternative host plants such as Saccharum angustifolium (Nees) Trin. and Andropogon bicornis L. at the edge of crop fields for shelter. The objective of this study was to investigate the population density between plants and tussock diameter, spatial distribution and sample size of E. meditabunda on A. bocornis and S. angustifolium at the edge of cultivated areas during soybean off-season. In both plants, the increase of tussock diameter resulted in a higher population density of E. meditabunda. Tussocks of S. angustifolium had a higher average number of stink bugs.plant-1 than A. bicornis. We observed an aggregation trend in both plant species. For practical applicability following Integrated Pest Management, a minimum sample size of 106 and 116 plants for A. bicornis and S. angustifolium respectively was obtained. Evaluation of host plants at the edges of crop fields during soybean off-season plays an important role in management strategies during the next cropping season.

Spatial distribution and sample size to estimate Lycosa erythrognatha (Araneae: Lycosidae) population density overwintering

Lycosa erythrognatha Lucas, 1833 (Araneae: Lycosidae) is a predatory arthropod with potential for conservation biological control. In addition to being considered a bioindicator of environmental quality, this arthropod provides an important service for agriculture by reducing insect-pest populations. In this work we seek to understand how the plants Andropogon bicornis L., Saccharum angustifolium Nees and Eustachys retusa Lag (Poales: Poaceae) and their different clump sizes affect the population density, spatial distribution and determination of the minimum number of samples to estimate its population density during the winter. Among the evaluated host plants, S. angustifolium and A. bicornis presented higher population density than E. retusa, but we observed that the clump diameter significantly influences the population density and the minimum number of samples. We observed a gregarious behavior in plants of A. bicornis and E. retusa. For S. angustifolium, a uniform distribution was observed.

Spatial distribution and sample size to estimate Euschistus heros population density in wild plants during off-season

The neotropical brown stink bug Euschistus heros (F.) is an important pest for many crops in several countries and its ability to survive on associated plants during winter is one of the main factors contributing to the permanence of this insect in crop areas. The objective of this study was to identify the spatial distribution of E. heros, and the minimum number of samples (tussocks of each plant species) required to estimate their population density in wild plants during winter. Field experiments were conducted in 2014, 2015, and 2016. Tussocks of Eustachys retusa, Andropogon bicornis, and Saccharum angustifolium were assessed in the area surrounding the cropped land. Data on the number of E. heros were categorized in plant species and tussock diameter range. The spatial distribution patterns of E. heros were evaluated using different dispersion indexes. To validate these patterns, the data were fitted to probabilistic distribution models. The minimum number of tussock samples required was determined using a statistical model. The results suggest that E. heros has an aggregate distribution in the three plant species evaluated; however, the distribution varies as a function of the tussock size. The numbers of tussock samples to achieve an accuracy within 30% were 146, 87, and 109 for E. retusa, A. bicornis, and S. angustifolium, respectively.

Predatory arthropods on alternative host plants in area surrounding by soybean-corn succession system

The objective of this work was to identify the diversity and abundance of predatory arthropods in three host plants over soybean and corn off-season. During the off-season harvest, from 2014 to 2018, Eustachys retusa, Andropogon bicornis and Saccharum angustifolium (Poales: Poaceae) plants were sampled in the area surrounding a soybean-corn succession system in the municipality of Cruz Alta, RS, Brazil. The number obtained for arthropods was sorted into species and number of individuals per species of host plant and clump diameter, used for statistical and SAD analysis. Over the five evaluation years, six species of predatory arthropods were identified, four coccinellids, one Carabidae and one spider (Lycosidae). The air temperature as well as the plant species and the clump diameter interfere in the population density of the sampled predatory arthropods. The analysis SAD showed prevalence for the Lycosa erythrognatha (Araneae: Lycosidae), followed by Harmonia axyridis (Coleoptera: Coccinelidae) for the host plants evaluated in the experiment. In conclusion, plants of E. retusa, A. bicornis and S. angustifolium shelter predatory arthropods in surrounding areas by soybean-corn succession system. The population density of these predatory arthropods is influenced by clump diameter of plants and air temperature during off-season.

Natural enemies in alternative plants during the soybean and corn offseason in Cruz Alta, Rio Grande do Sul

Identifying the behavior of natural enemies during the crop offseason is a key tool for integrated pest management. The objective of this work was to evaluate the population density of natural enemies of the plants Chloris distichophylla, Andropogon bicornis, and Erianthus angustifolium and to analyze the influence of the structural complexity of these plants on the present population. During the offseasons of 2014, 2015, and 2016, 150 plants of each species were evaluated and subdivided into different clump diameters. The species Lycosa spp., Eriops connexa, Cicloneda sanguinea, Coleomegilla quadrifasciata, Lebia concinna, and Harmonia axyridis were identified. A. bicornis was the plant with the highest population density, followed by C. distichophylla and E. angustifolium. Plants with greater structural complexities sheltered a higher population density of natural enemies.

Variación estacional de la composición florística en sabanas inundables en Arauca, Colombia

Mediante censos se documentó el recambio en la composición florística asociado al régimen de lluvias en comunidades de las sabanas de Arauca (Arauca, Colombia). Además, se cuantificó la abundancia relativa y el Índice de Valor de Importancia (IVI) de las especies en eventos de muestreo bimestrales a lo largo de un año. Se usaron transectos lineales con once puntos y once cuadrantes de 1 m2. Se registraron 110 especies y se obtuvo una correlación positiva entre la precipitación mensual y la abundancia de individuos, acompañada de un aumento del 85,7 % en la riqueza de especies en los meses de lluvias. Debido al mayor número de especies (96) la equitatividad de la comunidad fue mayor en el periodo de lluvias en tanto que, de las 57 especies de la época de sequía hubo dominancia de especies como Hydrolea spinosa, Melochia spicata, Peltaea sessiliflora, Cyperus luzulae, Acroceras zizanioides y Andropogon bicornis. El periodo de lluvias tuvo 53 especies exclusivas mientras que catorce lo fueron durante el periodo seco. Este estudio resalta la alta diversidad botánica que existe en las sabanas de la Orinoquia.

Manual Crowning Versus Cardboard in Forest Restoration: Costs and Effect on Seedling Development

ABSTRACT: Invasive grasses are one of the biggest obstacles to be overcome in restoration plantations. Thus, developing efficient and low-cost techniques to overcome this obstacle is a challenge for science and the ecological restoration practice. The objective of this study was to evaluate the effect of the use of cardboard for the crowning operation on the growth of forest tree species from the Atlantic Forest biome and on the operating costs of this technique in a reforestation implemented in Seropédica, Rio de Janeiro state. The predominant vegetation of the area was of Andropogon bicornis L. An experiment was installed in randomized blocks, with two treatments and 12 replications. The treatments consisted of crowning with cardboard and crowning with hoe. The used cardboard (50 x 50 cm) were pre-treated with a preservative solution with CuSO4. Treatments were applied to 11 forest species from the Atlantic Forest biome: Anadenanthera colubrina var. cebil (Griseb.) Altschul, Citharexylum myrianthum Cham., Enterolobium contortisiliquum (Vell.) Morong, Eugenia brasiliensis Lam, Eugenia uniflora Lam, Handroanthus chrysotrichus (Mart. ex DC.) Mattos, Hymenaea courbaril L., Inga laurina (Sw.) Willd., Plinia cauliflora (Mart.) Kausel, Plathymenia reticulata Benth. e Triplaris americana L. Evaluations were carried out as for height, diameter at collar height (DCH) and survival rate, 6, 12 and 18 months after planting. The costs of each crowning method were also quantified. Overall, the height, DCH and growth rates did not differ between the crowning treatments for the species evaluated. However, the cardboard crowning treatment showed a higher survival rate (80%) of plants, compared with the hoe crowning (73%). The cost of the crowning with cardboard over a 12-month period was 40% lower than that of the crowning with hoe. These results show that the cardboard crowning technique can be a viable and a cost effective alternative to replace the crowning with hoe in reforestation areas with species from the Atlantic Forest biome.

Population density of Tibraca limbativentris on flood irrigated rice and alternative host plants

Abstract: The objective of this work were to evaluate the population dynamics of the rice stem bug (Tibraca limbativentris) around and in flood irrigated rice cultivation area, to quantify the insect population flow between crops and host plants, and to determine the effect of the species, the diameter of the plant, and the distance of the host plant from the border on the rice stem bug population. The work was conducted in the 2012/2013 harvest and in the off-season, with sampling of rice, Andropogom bicornis, and Andropogon lateralis plants in six cultivated areas, in order to count the number of insects. The population density of the rice stem bug in irrigated rice and alternative host plants presents spatial and temporal dependence. In the cultivated areas, the population density of the rice stem bug increases according to the evolution of the rice phenological stages, with the highest densities concentrated in regions close to the crop borders. The diameter and species of the host plant affect the rice stem bug population. Andropogon bicornis plants have higher population densities than A. lateralis, and plants with larger diameters show higher population densities of the rice stem bug. In the off-season, the greatest population of the rice stem bug on host plants is concentrated up to 45 m from the crop border, but it can disperse until 150 m.

Densidade populacional de pentatomídeos influenciada pela estrutura morfológica de diferentes plantas no município de Cruz Alta, RS

The understanding of relationships between insects and host plants at their trophic levels is one of the greatest challenges to the ecological field. The objective of this study was to identify the influence of host plant species and clump diameters on the population density of phytophagous pentatomids. The study was carried out during the soybean and maize off-season in 2014, 2015 and 2016 at the Experimental Area of the University of Cruz Alta, Cruz Alta, RS. Host plants with different clump diameters of the species Chloris distichophylla (5, 10, 15, 20, and 25 cm), Andropogon bicornis, and Erianthus angustofolium (10, 20, 30, 40, and 50 cm) were evaluated. For each diameter of each plant species 10 experimental units were sampled per year, totaling 150 experimental units of each plant species at the end of three years. The diameter of host plant has direct influence on the phytophagous pentatomids. No significant differences were found among the host plants at the end of the three years of evaluations for the population of phytophagous Pentatomids.

Características generales del comportamiento del venado cola blanca (Odocoileus virginianus) en semicautiverio en Cobán, Alta Verapaz, Guatemala

En Guatemala, el venado Cola Blanca es de los animales cinegéticos más importantes y sin duda de los más perseguidos a pesar de eso, se han realizado pocos estudios sobre él. En la actualidad, con la formación de la colección de la Fábrica de Municiones del ejército-FME-localizada en el municipio de Cobán, en el departamento de Alta Verapaz, se busca asegurar la conservación de esta especie. El estudio consistió en observaciones diarias para determinar el comportamiento general: social, productivo, reproductivo del venado y colectas de campo realizadas en las épocas de menor y mayor precipitación, con el objeto de obtener información acerca de la calidad de las principales plantas forrajeras, mediante análisis por el método de Weende. Se cuantificó la disponibilidad del forraje, utilizando porcentajes estimados de cubierta, para las plantas herbáceas y para arbustos y árboles se usó el muestreo sistemático por medio de parcelas de 10 x 10 m. Las plantas forrajeras principales fueron hierbas graminoides por existir en mayor disponibilidad (75%), luego los arbustos (22%), y por último las especies arbóreas (3%). Los forrajes consumidos fueron generalmente de calidad inferior que los forrajes de otras latitudes. Dentro de las especies arbustivas cabe mencionar como las más importantes para el venado del área, el clavel de Panamá (Hibiscus rosasimensis),pera (Pyrus communis) y Costa Rica (Bahuinia sp.). Estas especies junto con gramíneas como Andropogon bicornis, Panicum sellowii y Paspalum conjugatum, constituyen la base alimenticia del venado Cola Blanca en la FME. Los datos presentados sobre comportamiento social, sugieren diferencias en algunas estrategias sociales y de comportamiento a una edad temprana entre la población estudiada en semicautiverio y los reportes para poblaciones que habitan áreas silvestres o en completo cautiverio. Las hembras generalmente tienen sus crías en marzo, con un pico de nacimientos al final de dicho mes, aunque este es un período que puede prolongarse hasta mediados de abril. Lo que se observa en Cobán es una estacionalidad en la época de partos, lo cual concuerda con los factores climáticos que están relacionados con la sobrevivencia de los cervatos. Se infiere que los cervatos nacidos durante los meses de marzo y abril tendrán una mayor probabilidad de sobrevivencia que aquellos nacidos después o antes de la estación.Cuando las lluvias fuertes se presentan los cervatos son capaces fisiológicamente de utilizar los recursos vegetativos disponibles para su crecimiento y desarrollo. Por otra parte, las madres se recuperan de la tensión fisiológica como consecuencia de la lactancia.

Pollen morphology of the Poaceae: implications of the palynological and paleoecological records of the southeastern Amazon in Brazil

ABSTRACTA detailed assessment of Poaceae pollen morphology was performed using light and scanning electron microscopy (LM and SEM, respectively), digital image processing and multivariate data analysis of species from the montane savanna (canga vegetation) of the Serra dos Carajas region in the southeastern Amazon to discriminate the lower taxonomic levels and, accordingly, the habitat types of Poaceae. Poaceae pollen are generally stenopalynous monoporate grains with annulate and operculate pores, and distinguishing species by ornamentation using LM is impossible. Under SEM, Poaceae have mainly areolate microechinate/granulose ornamentation, except for Eragrostis maypurensis (rugulate-microechinate), Andropogon bicornis, Trichanthecium parvifolium and T. polycomum (rugulate granulose), and Rhytachne gonzalezii (microechinate). Digital image processing of ornamentation under SEM coupled with multivariate data analysis allowed for differentiation between the E. maypurensis, R. gonzalezii, A. capillaris, Otachyrium versicolor, Paspalum carinatum and T. polycomum. Distinguishing species of the wet savanna, such as Isachne polygonoides, R. gonzalezii, O. versicolor, P. virgatum, and T. polycomum, from species of the dry savanna can improve paleoecological and paleoclimatic interpretations.

RECUPERACIÓN ECOLÓGICA DE ÁREAS AFECTADAS POR UN INCENDIO FORESTAL EN LA MICROCUENCA TINTALES (BOYACÁ, COLOMBIA)

<p>La microcuenca Tintales, ubicada en el Santuraio de Fauna y Flora (SFF) de Iguaque, Boyacá, fue afectada por un incendio forestal. En esa área se evaluó la regeneración natural en 29 parcelas permanentes. Se evaluaron dos fitofisonomías, afloramiento rocoso y robledal para comparar riqueza, diversidad y dominancia, obteniéndose mayor riqueza y diversidad en afloramiento rocoso. La familia Asteraceae fue la que obtuvo mayor representatividad, con dominancia de especies como <em>Hypoxis decumbens, Pteridium aquilinum </em>y <em>Andropogon bicornis. </em>La diversidad en todo el muestreo fue baja y homogénea debido a la reiterada incidencia de incendios forestales que han ocasionado cambios en la estructura y composición de la vegetación. La vegetación encontrada no difiere sustancialmente de otros estudios reportados para esta zona de vida y la región, donde las dinámicas de uso de suelo son similares, con alta deforestación e incendios. La vegetación establecida después del incendio es dominada por especies colonizadoras y pioneras. En las dos fitofisonomías estudiadas después de un año del incendio se establecen dos comunidades vegetales con diferencias estadísticas significativas en riqueza y homogeneidad. Para iniciar procesos de restauraciόn se recomienda usar como uno de los insumos las diferencias taxonómicas halladas entre robledal y afloramiento rocoso.<strong></strong></p>

Populations of phytophagous bugs influenced by crop background and wild plants

Plant-insect interaction governs the dynamics of insect populations with respect to their interrelation with the environment. The objective of the present study was to identify the influence of antecedent crops, species and diameters of wild plants on the quiescent population of phytophagous stink bugs. The experiment was conducted in the months of June and July in Parada Link, municipality of Santa Maria, Rio Grande do Sul state, Brazil in two fields under crops of rice and soybean. In the off season, alternative host wild plants such as Andropogon bicornis , Andropogon lateralis , and Erianthus angustifolius with 10, 20, 30 and 40 cm in diameter were selected. Six wild plants were sampled for each crop, species, and diameter, totaling 144 experimental units. The stink bug species were identified and quantified. Soybean and rice previous cultivation, as well as the species and diameter of the wild plant, influence the quiescent population of Dichelops furcatus , Edessa meditabunda , E. rufomarginata , Euchistus heros , Piezodorus guildinii , and Tibraca limbativentris phytophagous stink bugs. The host plants A. bicornis , A. lateralis , and E. angustifolius were utilized for the maintenance of the populations of phytophagous stink bugs in the off-season periods. Soybean cultivation in floodplain areas has a negative impact on the quiescent population of T. limbativentris .

Characterization of Poaceae (grass) species as indicators of the level of degradation in a stretch of riparian forest in Matutina, Brazil

Despite their extreme importance for environmental balance, riparian forests have been severely disturbed over time. This study aimed to identify grass species and determine their distribution in a disturbed stretch of riparian forest along Pimentas creek, in the municipality of Matutina, which is in the state of Minas Gerais, Brazil. Among four plots established within the study area, we recorded Pennisetum purpureum Schumach., Urochloa mutica (Forssk.) T.Q. Nguyen, Urochloa decumbens (Stapf) R.D. Webster, Paspalum notatum Flüggé and Andropogon bicornis L. The most common species was Pennisetum purpureum, which occurred in all of the plots, more frequently in those that had been disturbed. The proportions of exotic and native grasses, as well as their distribution, differed significantly among the plots. The distribution of the grass species varied according to the level of degradation of the creek bank, occurring more frequently where the bank had been disturbed. Therefore, we assume that grasses can be used as indicators of degradation in riparian zones. We also found that grasses are less efficient in preventing erosion than is the typical riparian vegetation.

Andropogon bicornis (Poales, Poaceae): A Hibernation Site for Pentatomoidea (Hemiptera: Heteroptera) in a Rice-Growing Region of Southern Brazil

Tussocks of Andropogon bicornis (Poaceae) make up a significant part of the landscape of the rice-growing region of south Brazil. However, little is known about their role in maintaining insect diversity in anthropized regions. We tested the hypothesis that A. bicornis is a hibernation site for Pentatomoidea (Hemiptera: Heteroptera) by analyzing the composition, structure, and diversity of pentatomoid assemblages over the course of a year. A total of 208 tussocks were removed at fortnightly intervals from April 2010 to March 2011. We collected 3,423 pentatomoid specimens belonging to 22 species distributed in 13 genera of three families, Pentatomidae, Scutelleridae, and Thyreocoridae. The most common species was Tibraca limbativentris Stål, the main rice pest in southern Brazil, followed by Oebalus ypsilongriseus (De Geer) and Edessa meditabunda (Fabricius). Abundance and species richness were the lowest in January, February, and March and the highest in July, August, and September. A combination of high species diversity observed during the colder months, including several unrelated to rice, and the absence of immature specimens in the tussocks strengthens the hypothesis that A. bicornis is a hibernation site for pentatomoids in the region.

Occurrence of Diapause and the Role ofAndropogon bicornis(Poaceae) Tussocks on the Seasonal Abundance and Mortality ofTibraca limbativentris(Hemiptera: Pentatomidae)

The rice stalk stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is a major pest of rice crops throughout Latin America. We investigated the occurrence of diapause in T. limbativentris, as well as the role of West Indian foxtail, Andropogon bicornis L.(Poaceae), in its seasonal abundance and mortality. This plant grows spontaneously in grasslands from Mexico to Argentina, including at the edges of rice fields in southern Brazil. Tussocks of A. bicornis were collected in Eldorado do Sul, State of Rio Grande do Sul, Brazil throughout one yr and examined to sample rice stalk stink bugs. We collected in 2,355 T. limbativentris adults from 208 tussocks, totalling 2,205 live and 150 dead individuals. Live insects were dissected to determine the reproductive stage and to assess the presence of the fat body. We describe the occurrence of imaginai diapause and the use of A. bicornis as a shelter for this rice pest. Overwintering lasted 7 mo; arrival at the refuge occurred in early autumn (late Mar); the permanence period began in Jun, and extended to the end of Sep. From Oct the population decreased gradually until total departure from the tussocks in Jan. Thus, here we highlight the role of A. bicornis as an hibernation site for T. limbativentris in southern Brazil.

Germination of native grasses with potential application in the recovery of degraded areas in Quadrilátero Ferrífero, Brazil

Native grasses are potential species to be used in land rehabilitation. However, due to the lack of better knowledge of their performance, preference is given to exotic plants, which may be invasive and negatively affect the local biodiversity. In order to better understand the propagation of native species of the Quadrilátero Ferrífero (Minas Gerais, Brazil) using their seeds, and in so doing, indicate possible candidates for land rehabilitation, this study investigated the germination patterns of the following grasses: Andropogon bicornis L.; Andropogon leucostachyus Kunth; Setaria parviflora (Poir.) Kerguélen; Cenchrus brownii Roem. & Schult; Echinolaena inflexa (Poir.) Chase, and Apochloa euprepes (Renvoize) Zuloaga & Morrone. The spikelets (depending on the species, removing or not the structures that surround the caryopsis) were treated as follows: T1-Control, T2-moistening with 0.2% potassium nitrate, T3-heating at 80 ºC for 2 minutes, T4-scarification with sulfuric acid (except genus Andropogon) and, for genera Andropogon and Setaria T5-storage at room temperature and T6- refrigerated storage. The treatment was repeated four times for 25 caryopses incubated at 25 ºC and constant light. Significant variation was observed when comparing germination rates from week to week, treatment to treatment and species to species. The most efficient treatment for genus Andropogon was T6, followed by T2 for A. bicornis and T3 for A. leucostachyus. T6 was also the most effective treatment for S. parviflora, followed by T5 and T2. C. brownii showed similar results when applying T1, T2 and T3 (mean 39%). E. inflexa and A. euprepes showed high levels of dormancy that were not overcome by the proposed treatments. A. bicornis, A. leucostachyus, S. parviflora and C. brownii showed higher germination potential, thus being possible candidates for the recovery of degraded areas. Future studies are indicated to find the most effective treatments for germination in field conditions.

Espécies de cerrado com potencial para recuperação de áreas degradadas por mineração de ouro, Paracatu-MG

Com o intuito de selecionar espécies que possam ser testadas na recuperação de áreas com alta concentração de arsênio, foram estudadas 10 áreas de Cerrado degradadas pelo garimpo de ouro em Paracatu, MG. Utilizou-se a escala de valores de cobertura e abundância de Braun-Blanquet, sendo as espécies classificadas também quanto à forma de vida de Raunkiaer. As áreas foram comparadas floristicamente pelo índice de Sørensen. Foram encontradas 197 morfoespécies lenhosas e herbáceas, das quais 102 foram identificadas em nível específico, 35 em gênero e 40 em família. Vinte morfoespécies não puderam ser identificadas. Houve grande variação quanto à riqueza florística entre as unidades amostrais (21-53 espécies), e esse fato influenciou a formação de três grupos na análise de similaridade florística. As espécies que se mostraram mais abundantes e provavelmente de maior adaptabilidade às condições ambientais foram: Axonopus marginatus, Simarouba amara, Aristida ekmaniana, Digitaria ciliaris, Stylosanthes viscosa, Andropogon bicornis, Maprounea guianensis e Sabicia brasiliensis. A forma de vida mais frequente foi fanerófito, seguida de hemicriptófito e caméfito. No espectro biológico, foi possível visualizar as diferentes estruturas das áreas estudadas, enfatizando-se a diversidade de ambientes presentes, apesar de apresentarem baixa riqueza florística.