Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 4 )

2019 ( 49 )

2018 ( 137 )

2017 ( 118 )

Custom range...

Search Results: 1 - 10 of 6260 matches for " secondary vegetation "
All listed articles are free for downloading (OA Articles)
Page 1 /6260
Display every page Item
Anthropogenic Disturbances and the Natural Vegetation Regeneration: A Case Study of a Forest Fragment Located in a Cuesta Relief Area, State of S?o Paulo, Brazil  [PDF]
Luiz Alberto Blanco Jorge, Vanessa Rodrigues Pereira
Open Journal of Forestry (OJF) , 2015, DOI: 10.4236/ojf.2015.56055
Abstract: The present study has been conducted in one of the five natural vegetation fragments at the Experimental Farm Edgardia, in Botucatu, São Paulo State, Brazil. In the past the forest fragment suffered disturbances due to the selective exploitation of tree species and the use of part of the surface as pasture. The objectives of this research were to evaluate the structure and the dynamics of natural vegetation. Three phytosociological surveys (2006, 2010 and 2014) were carried out in a sampled area of one hectare. The most abundant species were mapped in 2014, in a sampling unit with two hectares. Individuals of 37 families and 110 species have been recorded. The oscillation of the basal area observed through the forest inventories was due to the instability caused by disturbances. Only two out of the seven most abundant species mapped showed exponential diameter distribution. The unimodal distributions shown by the other five species have suggested that the vegetation has been occupying the most open spaces through regeneration in cycles. There was direct association between the spatial distribution and the dispersion syndrome for five out of the seven most abundant species. Three species have zoochoric dispersion, showing that wild animals populations have accomplished their function in the dispersion of seeds/fruit. The spatial distributions of four out of the seven most abundant species have provided evidence of how the regeneration of natural vegetation is being processed in this area.
Musgos (Bryophita) do nordeste Paranaense, Brasil -1. Zona Bragantina, microrregi?o do Salgado e município de Viseu
Santos, Rita de Cássia P. dos;Lisboa, Regina C. L.;
Acta Amazonica , 2003, DOI: 10.1590/S0044-59672003000300007
Abstract: this paper is an inventory of moss species occuring in diferent types of vegetation in the zona bragantina, salgado microregion and viseu municipalities, all located in the northeast of pará. the results found 60 species and one variety in 632 moss samples, distributed in 30 genera and 16 families. sematophyllaceae, calymperaceae e leucobryaceae were prominent in diversity of species and number of occurrencies. sematophyllum subsimplex (hedw.) mitt. and calymperes lonchophyllum schwaegr. are the most abundant species. the results found at salgado microregion were compared to the results found at zona bragantina and viseu municipalities. there is a higher diversity in primary vegetation, indicating that the replacement by the secondary vegetation results in the impoverishment of moss species diversity.
Estructura y composición florística de la vegetación del Parque Educativo Laguna Bélgica, Chiapas, México
Escobar-Ocampo, Ma. Consuelo;Ochoa-Gaona, Susana;
Revista mexicana de biodiversidad , 2007,
Abstract: the study was conducted in the parque educativo laguna bélgica (pelb). the objective was to characterize the vegetal associations to establish basis for management. the vegetation map was elaborated on interpretation of ortophotos, supported with field verification and processed using a gis. the characterization of the vegetation used the method of mueller-dombois and ellenberg. for forest inventories we registered woody species > 1 m height and > 3 cm diameter breast height. the coverage was evaluated in qualitative form based on braun-blanquet method. five types of vegetal associations were recognized: oak forest of quercus oleoides, oak forest of q. elliptica, tree-secondary vegetation, grasslands, and herbaceous succession. we find 159 woody species, and through revision of literature we complete a list of 254 species, which are included in 157 genus and 64 families. this work included 68 new records of woody species for the reserve. the flora of laguna bélgica shows bigger floristic affinities with the humid forests of the slope of the gulf than the central depression. our results emphasizes in the high woody diversity and the importance to conserve this small portion of native vegetation.
Composición florística y estructura de la vegetación secundaria en el norte del estado de Campeche, México
Zamora-Crescencio, Pedro;Domínguez-Carrasco, María del Rosario;Villegas, Pascale;Gutiérrez-Báez, Celso;Manzanero-Acevedo, Luis Ariel;Ortega-Haas, Juan José;Hernández-Mundo, Saraí;Puc-Garrido, Elda Celedonia;Puch-Chávez, Rosalía;
Boletín de la Sociedad Botánica de México , 2011,
Abstract: we studied species composition and structure of a ten year-old secondary forest in tepakán, campeche, mexico. we marked 20 plots of 5 × 10 m2 (1,000 m2 in total), where all individuals with a dbh ≥ 2 cm were measured. vegetation structure was characterized using the importance values of the species, and species diversity was estimated with the shannon-wiener (h') index. we recorded 1,150 woody individuals in 43 species, 35 genera, and 21 families. diversity was h'= 1.59. the fabaceae was the family with the highest number of species (14). cordia alliodora was the most important species according to its large stem density, followed by piscidia piscipula and acacia gaumeri. together they account for 33.9% of total importance value. these species are the most important in the structure and physiognomy of the community.
Microbial biomass and soil chemical properties under different land use systems in northeastern Pará
Lopes, Elessandra Laura Nogueira;Fernandes, Antonio Rodrigues;Lourdes Pinheiro Ruivo, Maria de;Cattanio, José Henrique;Souza, Gladys Ferreira de;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000400006
Abstract: the increase in agricultural production in the brazilian amazon region is mostly a result of the agricultural frontier expansion, into areas previously influenced by humans or of native vegetation. at the same time, burning is still used to clear areas in small-scale agricultural systems, leading to a loss of the soil productive capacity shortly after, forcing the opening of new areas. this study had the objective of evaluating the effect of soil preparation methods that involve plant residue shredding, left on the surface or incorporated to the soil, with or without chemical fertilization, on the soil chemical and biological properties. the experiment was conducted in 1995, in an experimental field of yellow latosol (oxisol) of the embrapa amaz?nia oriental, northeastern pará (brazil). the experiment was arranged in randomized blocks, in a 2x6 factorial design, with two management systems and six treatments evaluated twice. the management systems consisted of rice (oriza sativa), followed by cowpea (vigna unguiculata) with manioc (manihot esculenta). in the first system the crops were planted in two consecutive cycles, followed by a three-year fallow period (natural regrowth); the second system consisted of one cultivation cycle and was left fallow for three years. the following treatments were applied to the secondary forest vegetation: slash and burn, fertilized with npk (q+npk); slash and burn, without fertilizer npk (q-npk); cutting and shredding, leaving the residues on the soil surface, fertilized with npk (c+npk); cutting and shredding, leaving residues on the soil surface, without fertilizer (c-npk); cutting and shredding, with residue incorporation and fertilized with npk (i+npk); cutting and shredding, with residue incorporation and without npk fertilizer (i-npk). the soil was sampled in the rainier season (april 2006) and in the drier season (september 2006), in the 0-0.1 m layer. from each plot, 10 simple samples were collected in order to generate a co
Species Composition and Dispersion Pattern of Pitcher Plants Recorded from Rantau Abang in Marang District, Terengganu State of Malaysia
Jumaat H. Adam,Hafiza A. Hamid,Mohd Afiq Aizat Juhari,Siti Norhafizah Ahmad Tarmizi
International Journal of Botany , 2011,
Abstract: The study to determine the species composition and community structure of pitcher plants in Rantau Abang, Terengganu was carried out using plot method. Nepenthes gracilis was recorded in plots 1-3 at 10, 30 and 50 m, N. rafflesiana was recorded in P2 and N. ampullaria in P3. Nepenthes gracilis differs morphologically from the other two species by its sessile leaves, decurrent leaf base, angular stem shape, very thin peristome and partly glandular inner pitcher cavity wall. Nepenthes ampullaria differed by its panicle inflorescence, cuneate lids shape, narrower than the mouth glandless, lower lid surface, bearing up to 6-flowered bracteolate pedicels and urceolate lower pitcher. Nepenthes rafflesiana differed by infundibulate and ellipsoid upper and lower pitcher, densely glandular lower lid surface, toothed inner peristome margin. Population structures of these species comprised of seedlings, saplings and matured plants. These species consist of 52.61% of juvenile stage (seedlings and saplings) and 47.39% of matured stage. A total 5.68 and 2.84% of these species population bear male and female inflorescence. Morisitas Index of Dispersion Pattern and Chi-square test showed that the dispersion pattern of all life stages of these species was significantly aggregated. Their Id values were from 1.12 to 3.78. Matured plants and sapling of N. gracilis recorded the lowest and biggest Id. These species grow in soil that is acidic and low organic matter content. Nepenthes gracilis grows in sandy loam, loam and sandy clay; Nepenthes ampullaria and Nepenthes rafflesiana grow in sandy clay and loam.
Patrícia Aparecida de Souza,Nelson Venturin,Renato Luiz Grisi de Macedo,Maria Inês Nogueira Alvarenga
CERNE , 2001,
Abstract: This study was carried out on the margins of the Rio Grande at Monte Alegre Farm, in Ribeir o Vermelho county, Minas Gerais State, Brazil. The purpose of the study was to test 12 tree species for reclamation of an area degraded by the extraction of river bed sand. The experiment used 3,0 x 1,5 m spacing fo r testing 12 species distributed in a quinconx system. Soil fertilization varied inP leveles (100, 200, and 400g P/plant), chosen after soil chemical analyses. The source was simple super-phosphate. The statical design was randon blocks with a 12 x 3 design (12 species x 3 fertilizer levels), with a total of 36 treatments and 3 repetitions. The experiment contained 108 sample units. The interation species-fertilizer was not significant using treatment means. Two years after planting, the following was concluded: the degraded area is recovering, and the species are growing following the secondary succession pioneer, light-demanding climax and shade-tolerant species; preliminary observations indicated as most promising species Acacia mangium and Schinus terebinthifolius (survivorship in the field), Acacia mangium, (mean diameter at the ground level); and Schinus terebinthifolius, (crown area). These two species are thus recomended for the reclamation of areas degraded by extraction of river bed sand.
Notes on the floral morphology and phenology of Bacurizeiro (Platonia Insignis Mart.) Clusiaceae in Bragan a, Pará
Fábio de Jesus Batista,Mário Augusto Gon?alves Jardim
Boletim do Museu Paraense Emílio Goeldi : Ciências Naturais , 2006,
Abstract: Information on floral morphology, fruiting and flowering phenology were presented. This research was carried out in a natural population located in Benjamin Constant community, municipality at Bragan a, northeast of Pará State. Seven individuals of natural population were studied on phenology since this appearing of floral button at fruiting maturation. This description of floral morphology was made with lupa ZEISS. Platonia insignis Mart. is hermafrodite, showy flowers, solitary and roseate located in branch terminals, pedunculate, cyclical and radial simetry; flowering from August to December and fruiting from November to March. This specie presented partial synchronism and annual pattern for flowers and fruits.
Estimativa de área de vegeta??o secundária na Amaz?nia Legal Brasileira
Almeida, Cláudio Aparecido;Valeriano, Dalton Morisson;Escada, Maria Isabel Sobral;Rennó, Camilo Daleles;
Acta Amazonica , 2010, DOI: 10.1590/S0044-59672010000200007
Abstract: secondary vegetation has many relevant functions to the ecosystems such as atmospheric carbon fixation , maintenance of biodiversity, establishment of connectivity among forest remnants, maintenance of hydrological regime, and restoration of soil fertility. the objective of this work is to estimate the area occupied by secondary vegetation in the brazilian legal amazon (bla) for 2006 using a sampling scheme. the sampling is based on a stratified approach according to the degree of deforestation observed in the 229 tm-landsat scenes that cover the bla. thus, 26 scenes were selected for 2006 and distributed into seven strata, according to their degree of deforestation, in which secondary vegetation areas were mapped. a regression model was constructed to estimate secondary vegetation area in the remaining images using deforestation area, hydrographic area, agrarian structure , and area of conservation units, as independent variables. the regression analysis found an adjusted r2 of 0.84 and positive coefficients for the proportion of hydrography in the image (2.055) and for the agrarian structure (0.197), while negative coefficients for the degree of deforestation in the image (-0.232) as well as for the proportion of conservation unity(-0.262). using the multivariate regression model, an area of 131,873 km2 of secondary vegetation was estimated for the year of 2006. applying a monte carlo simulation we estimated an uncertainty of approximately 12,445 km2 .
Evaluación espacial y temporal de la vegetación de la Sierra Madrigal, Tabasco, México (1973-2003)
Salazar Conde, Erika del Carmen;Zavala Cruz, Joel;Castillo Acosta, Ofelia;Cámara Artigas, Rafael;
Investigaciones geográficas , 2004,
Abstract: this study was carried out in the sierra madrigal, tabasco state, méxico. the purpose was to evalúate the spatial distribution and transformation rate of tropical rain forest in 3 642 ha of sierra madrigal from 1973 to the year 2003. maps of vegetation and land use for the years 1973,1984, and 2003 were made trough the interpretation of aerial photographs at scale 1:20 000. the vegetation and land use were characterized in the field. the rate transformation of land used and vegetation were obtained, and some soil properties were compared, based on the type of vegetation. the tropical rain forest of ramón (brosimum nlicastrum) and huapaque (dialium guianenese) lost 80% of their original distribution ín 30 years. fire was de the principal cause of devastation of the rain forest, which led to the formation of secondary vegetation (56%) and grassland (10%) for cattle use. the change of rain forest to secondary vegetation and grassland diminished the organic matter and nitrogen in the layer of 0 to 30 cm of soil, which indicates a degradation.
Page 1 /6260
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.