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Search Results: 1 - 10 of 26 matches for " paramo. "
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EFECTO DE ACTIVIDADES AGROPECUARIAS EN LAS CARACTERíSTICAS DEL SUELO EN EL PáRAMO EL GRANIZO, (CUNDINAMARCA - COLOMBIA)
Luis Hernando,Estupi?án; Gómez,Jaime Eduardo; Barrantes,Víctor Javier; Limas,Luis Fernando;
Revista U.D.C.A Actualidad & Divulgación Científica , 2009,
Abstract: at the paramo el granizo (colombia), strategic for the capital district because of its hydric regulation and actually dedicated in a high percent to agricultural activities and cattle raising, an exploratory study was performed. the purpose of the research was to determine the effect caused by these activities on some physical and chemical soil characteristics. as references, areas without traces of human actions, areas with agricultural performances and / or livestock and areas in a resting period, were evaluated. it was proven that the agricultural practices cause negative effects on the soil characteristics of the paramo. as consequences, soil compaction, increase of bulk density and the decrease of moisture retention, stand out. in reference to the altered chemical properties, it was detected that the levels of nitrogen, of phosphor and the relation of bases were altered, influencing negatively the paramo′s natural conditions. in general it was observed that the augmentation of the farming frontier at the paramo makes that the soil is compacted in some cases and, in others, eroded and that the water retention, its main function, decreases, causing the well known negative consequences.
BRIóFITOS REóFILOS DE TRES QUEBRADAS DEL PáRAMO DE MAMAPACHA, CHINAVITA (BOYACá-COLOMBIA)
LAGOS-LóPEZ,MAYER ISNARDO; SáENZ- JIMENEZ,FAUSTO ALEXIS; MORALES-PUENTES,MARíA EUGENIA;
Acta Biológica Colombiana , 2008,
Abstract: in this study, 42 species of rheophylic bryophytes (21 mosses, 20 liverworts, 1 hornwort) were found. of them 18 are new reports for boyacá province. the families with more richness of species are bartramiaceae (4 spp.), brachytheciaceae, dicranaceae, pallaviciniaceae and jungermanniaceae (3 spp. each one). the bryophytes establishment is conditioned by the exhibition grade to the atmosphere, the availability of rocks and the competition with other bryophytes. finally, a commented catalogue with morphological, distribution and ecological data of the species is presented.
Destino del nitrógeno agregado por fertilización en un cultivo de papa en los andes de Venezuela
Abreu,Z; Sarmiento,L; Bottner,P;
Revista de la Facultad de Agronomía , 2007,
Abstract: the fate of nitrogen added by mineral fertilization was analyzed in a potato plot cultivated using 288 kg ha-1 of labeled n (15n) in the venezuelan moorlands and was compared to the n budged of an unfertilized plot. two samplings were carried out, 91 and 189 days after planting. the total and labeled n in the potato biomass and in three soil depths (0-10, 10-20 and 20-30 cm) were measured, by considering the mineral n (nh4+ and no3-), the n in the microbial biomass and the total n in soil. lysimeters were used to measure n losses by leaching. the potato yield was 14.5 t ha-1 in the fertilized plot and 1.2 t ha-1 in the unfertilized plot, showing the low intrinsic fertility of the soil. in the fertilized plot, at the first sampling date, 16% of the fertilizer n was in the crop biomass, 76% in the soil, 3% was lost by leaching and 5% was undetected for. at the second sampling, 23% of the applied n was in the crop biomass, 39% in the soil, 6% was lost by leaching and 32% was undetected for and probably lost to the atmosphere. n of fertilizer represented 69% of the total n absorbed by crop by showing the little availability of native n. despite the high quantity of n organic present in soil. 10% of labeled fertilizer was unmoved by the microbial biomass during the first sampling by diminishing to 7% during the second sampling. at first sampling, nh4+ as mineral form whereas at second one no3. was more abundant by evidencing the nitrification process that could favoured the loss gaseous.
Bromeliaceae de los páramos y subpáramos andinos Venezolanos
Morillo,Gilberto; Brice?o,Benito; Olica-Esteva,Francisco;
Acta Botánica Venezuelica , 2009,
Abstract: a preliminary floristic study of the bromeliaceae from the andean venezuelan paramos and subparamos is presented. the research follows traditional herbarium technics, and includes generic and specific descriptions, and keys to subfamilies, genera and species. illustrations of 19 species are provided. as a conclusion of this work, eight genera and 33 species were found. species are grouped under five main distribution patterns: seven species are endemic, 15 are andean, three are neotropical, three range from central to south america, and two are disjuncts. venezuelan paramo species of bromeliaceae comprize about 10% of total number of species in the country, and 33% of the species present in colombian paramos.
RASGOS DE HISTORIA DE VIDA DE ESPECIES EN UNA COMUNIDAD VEGETAL ALTERADA EN UN PáRAMO HúMEDO (PARQUE NACIONAL NATURAL CHINGAZA)
CáRDENAS-ARéVALO,GLADYS; VARGAS-RíOS,ORLANDO;
Caldasia , 2008,
Abstract: eleven life history traits of vascular plants morphology and regeneration) were studied in four sites with different degrees of disturbance. they belong to the same landscape unit and have similar topographic conditions. the four study sitesare located in the tunjo and piedras gordas valleys, paramo of palacio, chingaza national natural park, cundinamarca, between 3400-3600 m and at 4o45' 03'n, 73o50`50' w. these valleys (mainly the tunjo river valley) have a long history of disturbance by burning and livestock grazing; the native community is composed of espeletia killipii, chusquea tessellata and calamagrostis effusa. through analysis of vegetation classification and principal components analyses (pca), the species were grouped according to their similar traits; the abundance was analyzed according to the degree of disturbance. three species groups were identified and differentiated mainly by their morphologic traits: type of plant, growth form, habit and height. group one is characterized mainly by graminoid species (73%), erect habit (100%) in tussocks (68%) with height above 5 cm (60 %); the -abundance cover of the group is lower when the degree of disturbance increases, it is most abundant in places with light or no disturbance (33 and 30 % respectively). group two is characterized by dragging or prostrate herbs (76%) that form cushions or carpets (86%) with height of under 5 cm (79%), occuring in places with low disturbance, where it is most abundant (44 %). group three is characterized by herbs (88%) in rosettes (100%), that do not form cushions or carpets, was least abundant at the most disturbed site (8%).
Diversidad y distribución de mariposas Satyrinae (Lepidoptera: Nymphalidae) en la cuenca del río Coello, Colombia
García-Perez,Jack F; Ospina-López,Leonardo A; Villa-Navarro,Francisco A; Reinoso-Flórez,Gladys;
Revista de Biología Tropical , 2007,
Abstract: diversity and distribution of satyrinae butterflies (lepidoptera: nymphalidae) in the coello river basin, colombia. we describe the patterns of diversity and distribution of the subfamily satyrinae in the coello river basin (4o 17? 08?? n - 74o 35? 36?? w; 1 899.31 km2) from 433 to 3 600 m. eleven sampling stations were located, in several ecosystems. the samples were collected during a period of 11 days, in march, may, july and october 2003, in three types of habitat (forest, forest edge and meadow). we collected at random, between 09:00 and 15:00 hr, using entomological nets. a total of 239 individuals (13 genera, 34 species) were collected. the most abundant species were in the genus pedaliodes (41.4 %). richness and diversity had high values in mountainous zones and paramo (> 2 000 m). the greater diversity was measured in the forest edge. the similarity analysis produced two groups: species from warm (euptychia hesione and hermeuptychia hermes) and middle (pseudohaetera hypaesia and taygetis celia) climate zones; and species from mountain and paramo (lymanopoda obsoleta, pedaliodes polusca and eretris calisto). rev. biol. trop. 55 (2): 645-653. epub 2007 june, 29.
Taxonomía y distribución de Nathalis (Lepidoptera: Pieridae) en Colombia
Pulido-B,Hannier W; Gonzalo Andrade-C,M; Llorente-Bousquets,Jorge;
Revista de Biología Tropical , 2010,
Abstract: the taxonomy and distribution of nathalis (lepidoptera: pieridae) in colombia. in colombia, nathalis has two described species: n. iole and n. plauta. previous authors did not make detailed descriptions of its distribution in meridional regions and failed to differentiate both species based on genitalic characters. some wing marks have been enough to separate them, but co-specificity was a possibility. they inhabit colombia above 2000 m in the paramo, and have a vicariant distribution from the remaining population of n. iole in the antillean and central and north america. an analysis focused on male and female genitalia, as well as the wing pattern of more than 100 specimens from the colombian andes (sierra nevada de santa marta and sierra de perijá) and mexico, indicates that the two species differ in their genitalia, and considering their allopatric distribution, we support the specific distinction of n. iole and n. plauta. we describe a new endemic subspecies found exclusively in the paramo above 3000 m, an area where other endemics occur. it has phenotypic plasticity related to environmental factors. rev. biol. trop. 58 (1): 273-285. epub 2010 march 01.
EFECTO DEL GRADIENTE ALTITUDINAL SOBRE ASPECTOS AUTOECOLóGICOS DE ESPELETIA PYCNOPHYLLA ssp. ANGELENSIS CUATREC. (ASTERACEAE) EN EL PáRAMO EL INFIERNILLO (NARI?O-COLOMBIA)
Benavides-Martínez,Iván F.; Burbano-Martínez,Diana L.; Urbano-Apráez,Sandra M.; Solarte-Cruz,María E.;
Actualidades Biológicas , 2007,
Abstract: some autoecological features of espeletia pycnophylla ssp. angelensis cuatrec. such as its demographic structure, population density, spatial pattern of dispersion, production of reproductive structures, adult morphometry and survivorship, were studied in an altitudinal gradient on a dry paramo of nari?o (colombia). hypothesis proposed by other authors about a linear effect caused by the elevation on these variables were completely rejected. the elevation induces an ecoclinal effect on population density, and this density correlates negatively with both production of reproductive structures and adult sizes. these results elucidate an unequivocal effect of density-dependence phenomena on population fitness. the intermediate zone of the altitudinal gradient exhibits a high population density, but on the other hand show reduced corporal adult sizes, minimal production of reproductive structures and the probability of juveniles reaching advanced ages is low. evidently, this intermediate elevation can have favorable ecological conditions for the seedling establishment, wich increments population densities at long term. we propose that other author's generalizations about the influence of elevation on the autoecology of these plants are limited, because the particular life and disturbance stories of paramos and the spatial, ecological and genetic isolating are explicative factors impossible to take away from the context. the demographic structure of the population fitted the logarithmic model, revealing its early regeneration state from the last fire event on 2003 and the similarity of the survivorship curves among every elevation, probed a high demographic stability.
PATRONES EN LA DISTRIBUCIóN DE LA VEGETACIóN EN áREAS DE PáRAMO DE COLOMBIA: HETEROGENEIDAD Y DEPENDENCIA ESPACIAL
ARELLANO-P.,HENRY; RANGEL-CH.,J. ORLANDO;
Caldasia , 2008,
Abstract: two methods of exploratory spatial data analysis (esda), analysis of spatial heterogeneity and dependence (auto-correlation), - - were applied to the cover patterns from ten paramo localities in the central and eastern cordilleras of colombia. among the localities studied, the high montane region of the serrania de perija, the paramo region of the los nevados national park, and the paramo region under management of corpoguavio showed a good state of conservation and satisfactory level of connectivity among patches. anthropic intervention, expansion of potato cultivation and other changes in land use mainly in the paramos of the cordillera oriental have alteredd the distribution patterns of natural vegetation types and resulted in significant losses of connectively. under the circumstancesany attempt to restore the original conditions will be difficult and expensive. this problem is most acute in the paramo localities of la rusia, belén, guantiva (towards the eastern slopes) telecom, merchan tablazo, the northeastern sector of the paramo of sumapaz and the eastern slopes of the mountains of carmen de carupa and surrounding areas. for the mountains of guanacaste and las delicias (areas influenced by the volcano puracé) the problem is more acute towards the northwestern sector. the results of the present study can be applied to ecological restoration and conservation as they provide detailed information about the distribution of vegetation types andhabitatconnectivity, both indicators of ecosystem health.
TELEDETECCIóN DE LA VEGETACIóN DEL PáRAMO DE BELMIRA CON IMáGENES LANDSAT
POLANCO LóPEZ DE MESA,JORGE ANDRéS;
DYNA , 2012,
Abstract: the purpose of this study is to distinguish the forest of belmira's páramo from other land cover classes. three landsat images are available (1996, 2002 and 2003). remote sensing analysis of the vegetation coverage includes image correction and classification and validation process. the cos(t) model and the quadratic interpolation function were used for image correction. the iterative self-organizing cluster analysis is considered for image non supervised classification and the maximum likelihood classifier is taken into account for image supervised classification. 70 gps land observations and the error matrix analysis, were used for validation process. the result is a map for each image, with two land cover categories: forest & non-forest. classification error is 2% and map-land observations correspondence is 80%. however, the presence of clouds and shadows affect the remote sensing accuracy.
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