Escuela de Ciencias Ambientales

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14682

La Escuela de Ciencias Ambientales (EDECA) de la Universidad Nacional contribuye con la sociedad costarricense y de otras naciones, especialmente centroamericanas, a forjar un desarrollo humano con mejores relaciones entre el ambiente y la sociedad, mediante la formación de profesionales competitivos y con una visión holística, en los campos de las ciencias forestales, educación ambiental y gestión del ambiente. Desde sus áreas estratégicas, la EDECA se posesiona en campos emergentes dentro de éstas, con enfoques holísticos y que tienen repercusión e impacto regional, tales como los servicios ambientales, la certificación forestal, los mercados alternativos y el desarrollo local, la gestión del ambiente y la gestión empresarial.

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Mostrando 1 - 20 de 233

Ornithology in Central and South America: Cause for Optimism?
(Universidad del Sur de Florida, 1988-04) Cameron Duffy, David
Se ha prestado especial atención a la necesidad de aumentar considerablemente los esfuerzos en materia de formación e investigación en América Central y del Sur (Short 1984, Mares 1986, James 1987). El argumento general es que hay muy pocos investigadores que producen muy poca investigación sobre la increíblemente diversa avifauna neotropical. Si bien se necesitan más biólogos y mejor formados en América Latina, sugiero que los norteamericanos y europeos simplemente desconocen gran parte del trabajo que se realiza allí. Al mismo tiempo, muchos latinoamericanos carecen de acceso a revistas especializadas y desconocen las investigaciones realizadas por extranjeros. Hay varios métodos posibles para mejorar la situación. James (1987) analizó las citas neotropicales sobre aves en el Zoological Record entre 1972 y 1983 y encontró tasas de publicación de 0,25/año (Nicaragua) a 25,1/año (México). El Zoological Record es una excelente referencia para la literatura científica del hemisferio norte. Sin embargo, creo que gran parte o incluso la mayoría de los resultados ornitológicos latinoamericanos se producen en revistas «internas» o en formas aún más inaccesibles de literatura «gris» no publicada. Muchas instituciones prefieren que su personal publique en su propia revista y en su propio idioma. Estas revistas suelen ser irregulares y se utilizan principalmente para el intercambio con otras publicaciones científicas. Muchas de estas revistas cubren una amplia variedad de temas, de los cuales la ornitología constituye solo un pequeño porcentaje, por lo que la suscripción no tiene sentido desde el punto de vista económico para personas y organizaciones con intereses más específicos.
Desarrollo larval de cichlasoma sp (pisces : cichlidae) cultivados en laboratorio
(Universidad Nacional de Costa Rica, 1988-09-29) Murillo Sánchez, Roger E.
Se describe el desarrollo embrionario y larvario de Cichlasoma sp. tras la fecundación natural de los huevos. Los huevos se obtuvieron de adultos capturados en la Hacienda Santiago, Heredia, Costa Rica. Se mantuvieron en acuarios a 24,5 ± 10,2 °C, 6,4 ppm de O₂ y un fotoperiodo de 12:12 horas. Los huevos son oblongos, de 2,1 mm de longitud y 1,6 mm de ancho. La eclosión ocurre entre las 48 y 52 horas posteriores a la fecundación. Al eclosionar, las larvas miden 4,6 ± 0,1 mm de longitud. El alimento se consume al noveno día después de la eclosión; la alimentación comienza al séptimo día. La fase juvenil comienza con una longitud de 15,5 ± 0,6 mm. La secuencia de desarrollo de las aletas es: pectorales, caudal, anal y pélvicas.
FRUTA DORADA (VIROLA KOSCHNYI WARB.) UNA ESPECIE PROMISORIA PARA LA REFORESTACION EN EL BOSQUE HUMEDO Y MUY HUMEDO TROPICAL
(Universidad Nacional de Costa Rica, 1990-04-30) Eladio, Chaves S; Rodríguez, Johnny; González, Eugenio
We present forestry experiences on the establishment and management of Virola koschyni Warb (Myristicaceae), a tree species from the tropical wet forest. In the nursery, plants were successfully produced by keeping soil brick and pruning the roots. Data from permanent thinning and yield plots showed that after six years, Virola koschyni reached an average 13.3 cm of DBH and 10.5 m of height. In addition, we include ecological and silvicultural information on this little known species.
NUEVAS ESPECIES DE INGA MILLER (MIMOSACEAE) PARA MESOAMERICA
(Universidad Nacional de Costa Rica, 1990-07-16) Zamora V, Nelson.
A partir de un estudio de las Mimosaceae de Costa Rica, se describen aquí nueve especies de Inga nuevas para la ciencia. Se incluye su distribución y afinidades taxonómicas.
Biological Activity of Extracts of Trichilia Species and the Limonoid Hirtin Against Lepidopteran Larvae
(Elsevier Science Ltd, 1994) Xie, Y. S.; Isman, M. B.; Gunning, P.; Mackinnon, S.; Arnason, J. T.; Taylor, D. R.; Sánchez. V, P.; Hasbun, C; Towers, G. H. N.
Crude extracts of several Trichilia species (Meliaceae) were evaluated for their behavioral and physiological effects on the polyphagous lepidopterans Peridroma saucia and Spodoptera litura. A majority of extracts of nine Trichilia species, collected primarily from Costa Rica, significantly deter larval growth of P. saucia. Extracts of wood and bark are generally more active than those of foliage. Effects of various tissue extracts from T. connaroides on P. saucia and S. litura were comparatively studied. Extracts of bark, the most active tissue compared to those of wood, seed, exocarp and leaf, reduced larval growth of P. saucia and S. litura by 50% at dietary concentrations of 29.1 and 185.1 ppm, respectively. The limonoid hirtin, a constituent of Trichilia hirta, significantly inhibited larval growth of P. saucia in a dose-dependent manner, with a dietary EC50 (effective concentration to inhibit growth by 50% relative to controls) of 13.0 ppm. Hirtin and various extracts from T. connaroides significantly reduced larval growth and consumption rates, as well as dietary utilization, indicating that these substances possess both behavioral effects and post-ingestive toxicity.
Resistance and resilience in a directly regenerating rainforest: Nicaraguan trees of the Vochysiaceae after Hurricane Joan
(Elsevier, 1994-10) Boucher, Douglas H.; Vandermeer, John H.; Mallona, María Antonia; Zamora, Nelson; Perfecto, Ivette
Two trees of the family Vochysiaceae, Vochysiaferruginea and Qualea paraensis, were abundant in a Nicaraguan rainforest which was heavily damaged by Hurricane Joan in 1988, and both had recovered their previous densities by 1993. However, their regeneration followed quite different paths. Vochysia suffered complete mortality of adult trees in the hurricane, but rapid growth and high survivorship of its abundant seedlings and sprouts of saplings, restored its population density (though not yet its mean diameter at breast height) and indeed led to spatial expansion. Qualea, however, showed 100% survival of trees during the hurricane but substantial mortality in the following years. Although seedlings and sprouts of Qualea are quite rare, ingrowth is sufficient to maintain the population so far. However, vine growth on Qualea (unlike Vochysia) is substantial. These two species are thus contrasting elements of the 'direct regeneration' which has been observed in this rainforest. The Vochysia pattern of death and recovery can be described as 'resilience', while the Qualea pattern of survival can be called 'resistance'. The regenerating Vochysia population is mostly seedlings and saplings, while that of Qualea is mostly adult trees. Depending on the pattern of regeneration, different management strategies will be appropriate for maintaining tree species subject to natural disturbances such as hurricanes and/or artificial ones such as logging.
Insecticidal defenses of piperaceae from the neotropics
(Universidad Nacional, Costa Rica., 1995) Chams, BERNARD.; KRISHNAMURTY, H.G.; CHAURET, D.; DURST, T; PHILOGIENE, BJ.R.; SANCHEZ-VINDAS, P; HASBUN, C.; POVEDA, L; San Román L; ARNASON, J.T.
Insecticidal and growth-reducing properties of extracts of 14 spe cies of American neotropical Piperaceae were investigated by inclusion in diets of a polyphagous lepidopteran, the European corn borer, Ostrinia nubit alis. Nutritional indices suggested most extracts acted by postdigestive tox icity. Piper aduncum, P. tuberculatum, and P. decurrens were among the most active species and were subjected to bioassay-guided isolation of the active components. Dillapiol was isolated from the active fraction of P. adun cum, piperlonguminine was isolated from P. tuberculatum, and a novel neo lignan from P+ decurrens. The results support other studies on Asian and African Piper species, which suggest that lignans and isobutyl amides are the active defence compounds in this family.
Altitudinal zonation of montane Quercus forests along two transects in Chirripó National Park, Costa Rica
(Springer, 1995-08) Kappelle, Maarten; Van Uffelen, Jan-Gerrit; Cleef, Antoine
Abiotic and vegetation data were collected along two altitudinal transects through mature montane Quercus forests on the Pacific and Atlantic slopes of Costa Rica's Chirripó Massif. Between 2000 and 3200 m asl twenty-four 0.05 ha forest plots were selected at altitudinal intervals of 100 m, and eight soil profiles were described at intervals of 200 m. A TWINSPAN classification aided in the determination of eight zonal forest communities on the basis of their floristic composition. They are grouped in two sets of four: (i) the palm-rich lauraceous-fagaceous Lower Montane Mollinedia-Quercus Forests (2000-2600 m asl) and (ii) the bamboo-rich myrsinaceous-fagaceous Upper Montane Schefflera-Quercus Forests (2500-3200 m asl), respectively. Vegetation changes seem correlated with two major climatic gradients: (i) a temperature gradient (altitude), and (ii) a moisture gradient (wet Atlantic vs. moist Pacific slope). Most soils are Andepts, and residual, colluvial or derived from volcanic material. Humus layers are thicker on the wetter Atlantic slope. A total of 431 vascular plant species consisted of 86 pteridophytes, 1 gymnosperm, 296 dicots and 48 monocots. Species richness, canopy height and stem diameter decrease with increasing altitude, while the canopy surface becomes more flattend. A comparison with other studies shows that Chirripó's montane Quercus forests fit within the environmental ranges known from altitudinal zonations elsewhere in the Tropics. © 1995 Kluwer Academic Publishers.
Crecimiento inicial de una plantación mixta de Quercus, Cornus, Alnus y Cupressus en Costa Rica
(Universidad Nacional, Costa Rica., 1996) Chaverri, Adelaida; Zúñiga, Edwin; Fuente, Anael
Tbe growth of an eleven year old, míxed plantation Qf four native tree species (Quercus seemannii, Q. . pitarius, Comus disciflora and Alnus acuminata) and an exotic species (Cupressus lusitanica) was studied in San José de la Montafia, Heredia, Costa Rica. C. lusitanica had the Iargest diameter (23.46 cm), and A. acuminata, the greatest height (22.08 m). Q. pitarius had the 10west diameter growth rate (0.52 cm/yr), C. lusitanica showed the highest diameter growth rate (2.13 cm/yr) while C. disciflora had a medium growth rate (1.28 cm/yr). Tbe best architectural qualities were seen in A. acuminata and C. lusitanica, followed by C. disciflora. Growthand . IifChitectural data @ow that Iiglít intolerant species A. acuminata and C. lusitanica grow well in míxed p1antati9!ls. Slower growing oales, known as tolerant species, need more Iight. Tbinning· operations around or before age seven 1ü"é recornmended, especially lo iinprove growth of Quercus species.
Characterisation of IndoorAir Quality in Large Urban Centres in Central America
(Universidad Nacional, Costa Rica, 1997) Alfaro, María Del Rosario
Levels of gas and particle-phase substances present in the indoor air at non-industrial sites in Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama; including offices, hospitals and restaurants, were measured during 1993 and 1994. Samples collected at 40 sites were analysed for respirable suspended particles (RSP, d50 <3.5 μm), ultraviolet RSP (UV-RSP) as a marker for environmental tobacco smoke, carbon monoxide, carbon dioxide, and nicotine. Levels of RSP were very high at several sites, varying within the ranges of 34-421 μg/m3 in restaurants, 21-242 μg/m3 in hospitals and 13-196 μg/m3 in offices. Carbon monoxide levels were also high at several sites with peak concentrations reaching 29, 20, and 19 ppm, respectively, in an office, a hospital and a restaurant. Infiltration and penetration of outdoor pollutants into the indoor environment occurred at all sites studied.
Anti-inflammatory activity of aqueous extracts of Ove Costa Rican medicinalplants in 8prague-Dawley rats
(Universidad Nacional, Costa Rica, 1999) BadilIa, Beatriz; Mora, Gerardo; Poveda, Luis Jorge
The anti-inflamrnatory properties of Loasa specic¡sa and Loasa triphylla (Loasaceae), Urtica leptuphylla and Urera baccifera (Urticaceae), and Chaptalia nutans (Astemceae) were studied using the carregeenan induced mt paw edema model. Aqueous extmcts of each plant were made according to the ethnoboranical use. The hippocratic assay was made with female mts; the dose used was 500 mglkg i.p. andthe control group received 0.5 mi of n.s.s .. A11 the lmimals treated showed hipothermia, and those treated with the extmcts of Chaptalia nutans, Urera baccifera and Urtica lept/lPhylla showed an increased colinergic activity. Acute toxicities of !he aqueous extmcts were studied in mice an tbe mean lethal doses ranged between 1.0226 and 1.2022 glkg. The extracts of Urera baccifera, Chaptalia nutans, Loasa speciosa and Loasa triphylla (500 mglkg i.p.) showed an anti inflarnmatory activity compamble with that of indomethacin. The extracts of U. baccifera and C. nutans, which showed the gI"tatest anti-inflamrtJatory activity, did not show it when used orally (500 mg/k:g p.o.).
Screening of Costa Rican Trichilia species for biological activity against the larvae of Spodoptera litura (Lepidoptera : Noctuidae)
(Elsevier Science Ltd, 2001-04) Wheeler, Deborah A.; Isman, Murray B.; Sanchez Vindas, Pablo; Arnason, John T.
Crude methanolic extracts made from the twigs of 39 plant samples from six species of Trichilia collected in Costa Rica, were incorporated into arti®cial diet and fed to neonate Spodoptera litura larvae. All six plant species tested signi®cantly reduced larval growth after 7 and 10 days. The most active species was T. americana, reducing growth, on average, to 3.9% of control at 1000 ppm fresh weight. The least active, on average, was T. glabra. A twig extract of T. americana proved to be more active than wood, bark or leaf extracts, with the twigextract reducing growth of S. litura larvae by 50% (EC50) at a dietary concentration of 17.2 ppm. When T. americana wood extract was incorporated into arti®cial diet (10, 25, 50 and 75 ppm) and fed to S. litura larvae throughout larval development, growth was slowed and the nal weight of pupae and adults was reduced. At higher extract concentrations (50 and 75 ppm) larvae entered one or two supernumerary instars before pupation occurred. This was shown to be due to both starvation and to post-ingestive activity of the extract.
Anti-inflammatory and antinociceptive activities of Loasa speciosa in rats and mice
(Elsevier, 2003) Badilla Baltodano, Beatriz; Arias, A. Y.; Arias, M.; Mora, G. A.; Poveda Alvarez, Luis
In the range of doses of 250–500 mgykg (given i.p.) the aqueous extract of Loasa speciosa leaves showed an inhibitory effect on leukocyte migration, and a reduction on the pleural exudate, as well as dose-dependent anti-inflammatory and peripheral antinociceptive activities.
Inhibition of human pathogenic fungi by ethnobotanically selected plant extracts
(Deutschsprachige Mykologische Gesellschaft, 2003-02-14) Ficker, Christine E.; Arnason, J. T.; Sanchez Vindas, Pablo; Álvarez, L. P.; akpagana, koffi; Gbéassor, M.; De Souza, C.; Smith, M. L.
In this study, 36 extracts derived from 29 plant species selected using an ethnobotanical approach were tested for antifungal activity against a taxonomically diverse group of 13 human pathogenic fungi. We compared the inhibitory characteristics of these plant extracts with those of the commonly used antifungals, amphotericin B and ketoconazole, and the plant-derived antifungal, berberine. Several plant extracts, notably those from Zingiber officinale (ginger) and Juglans cinerea (butternut), had pronounced antifungal activity against a wide variety of fungi, including strains that were highly resistant to amphotericin B and ketoconazole. Further exploration of Z. officinale as an antifungal is warranted as this species is generally regarded as safe for human consumption.
Una nueva especie de Eugenia L. (Myrtaceae) de las selvas húmedas costarricenses
(Universidad de Costa Rica., 2004) Sánchez Vindas, Pablo
Se describe una nueva especie de Eugenia (Myrtaceae) de las veinte caribe de Costa Rica. Se distingue por las hojas con doble nervio marginal y los frutos acostillados y muy reticulado.
Heartwood, sapwood and bark contents of bombacopsis quinata in Costa Rica
(Instituto de Investigación Forestal de Malasia, 2004-07) Pérez, D.; Kanninen, M.; Matamoros, F.; Fonseca, W.; Chaves, E.
The Costa Rican government has promoted the establishment of high yielding plantations, expecting to produce high quality timber. Nowadays the management of some species have been uncertain, since wood quality and yield are becoming lower than expected. Heartwood content is a determinant characteristic for Bombacopsis quinata, a widely appreciated species in the country. The aim of this study was to evaluate the heartwood, sapwood and bark content of young and advanced aged B. quinata trees. The research was based on the hypothesis that heartwood content increases with increasing age. By means of stem analysis, the heartwood, sapwood, and bark volume was measured on trees of different ages (10 to 27 years). The highest heartwood proportion found in B. quinata was 13.6%, and the lowest 0.1%. The sapwood ranged between 70.0 and 87.2% while the bark, from 9.4 to 23% of the total stem volume. No clear differences in heartwood content could be observed between trees of similar age from dry and wet zones. Rotation periods for B. quinata in Costa Rica should be extended to produce high quality timber with increased heartwood content.
Anti-HIV activity of dibenzylbutyrolactone-type lignans from Phenax species endemic in Costa Rica
(Universidad Nacional, Costa Rica, 2005) Piccinelli, A. L.; Mahmood, N; Mora, G.; Poveda, L.; De Simone, V; Rastrelli, L.
Previously, we isolated two new dibenzylbutyrolactone-type lignans, named phenaxolactones 1 and 2, from the leaves of Phenax angustifolius Wedd. (Urticaceae). In this investigation three new dibenzylbutyrolactone lignans (phenaxolactones 3–5), together with phenaxolactone 1, and fla vones vitexin (6), isovitexin (7), were isolated from Phenax rugosus Wedd. leaves collected in Santa Ana, Costa Rica. The structures were elucidated using 1D and 2D NMR spectroscopy as well as mass spectrometry. Phenaxolactones 1–5 and flavones 6 and 7 were evaluated for their inhibitory activity against HIV-1MN in infected C8166 cells. The most promising compound was phenaxolactone 1 with an EC50 value of 3.0 M, no cytotoxicity at 112 M and a therapeutic index value of 37.3
A regression analysis of Q'eqchi' Maya medicinal plants from southern Belize
(Universidad Nacional, Costa Rica, 2006) Sánchez Vindas, Pablo
Amiguet, V.T., Department of Biology, University of Ottawa, P.O. Box 450, Ottawa, Ont. K1N 6N5, Canada; Arnason, J.T., Department of Biology, University of Ottawa, P.O. Box 450, Ottawa, Ont. K1N 6N5, Canada; Maquin, P., Belize Indigenous Training Institute, Punta Gorda, Toledo District, Belize; Cal, V., Belize Indigenous Training Institute, Punta Gorda, Toledo District, Belize; Sänchez-Vindas, P., Herbario Juvenal, Universidad Nacional, Heredia, Costa Rica; Alvarez, L.P., Herbario Juvenal, Universidad Nacional, Heredia, Costa Rica
Cuatro compuestos nuevos del extracto no polar de la planta Amyris brenesii (Rutaceae) de Costa Rica
(Universidad de Costa Rica., 2008) Chavarría, Max; Castro, Victor; Poveda, Luis; Murillo, Renato
El estudio fitoquímico de las partes aéreas de Amyris brenesii (Rutaceae) recolectadas en Río Cuarto, Grecia, Alajuela (Costa Rica) mostró la presencia de cuatro nuevos compuestos: la 6-hidroxi-6-O-(3-hidroximetil-3-metilalil)- angelicina 1, el 6-(N-acetil-etanamin) -2,2-dimetil-2Hcromeno 2, el lignano 2,5-deshidrohinokinina 3 y la N-acetil-O-(geranil)-tiramina 4. Adicionalmente se aislaron los lignanos hinokinina 5, y justicidina E 6, las cumarinas escopoletina 7 y marmesina 8, el ácido 24-moretenoico 9 y el O-(3,3-dimetilalil)-halfordinol 10. Las separaciones se llevaron a cabo mediante la aplicación de técnicas cromatográficas y la elucidación de las estructuras se realizó con la ayuda de técnicas espectroscópicas de Resonancia Magnética Nuclear (RMN) de una y dos dimensiones.
Chemical composition of bulk precipitation in the metropolitan area of Costa Rica, Central America
(Universidad Nacional de Costa Rica, 2009-05-04) Herrera, M. J.; Rodríguez, R. S.; Báez, A. P.
Tracemetals and inorganic ionswere measured in bulk precipitation sampled at eleven sites in the metropolitan area of Costa Rica. The ions were analyzed by ion chromatography, and the trace metals by atomic absorption spectrometer with a graphite furnace attachment. The results indicated that Na+ and SO4 2− were the most abundant ions, and of the metals, that Al and Fe had the highest concentrations. Spearman's correlation applied to all data showed a high correlation among SO4 2−, NO3− and NH4+, indicating a common anthropogenic origin. In addition, the correlation found between Na+, K+ and Cl−indicated a sea aerosol contribution. High positive correlations between tracemetalswere found for Al–Mn, Ni–Mn, Ni–Al, Cu–Ni, Pb–Cu, Pb–Ni and Pb–Mn.

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