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Mostrando ítems 1-10 de 107
Transformación del paisaje de selvas de montaña en la cuenca del río Capaz, Andes Venezolanos
(2009-12-31)
La deforestación de selvas tropicales de montaña es una de las principales causas de la pérdida de
la biodiversidad de nuestro planeta. Entre 1981 y 1990 Venezuela presentó las mayores tasas de
deforestación de ...
Vegetation structure along the forest - páramo transition belt in the Sierra Nevada de Mérida: implications for understanding treeline dynamics
(SABER ULA, 2009-12-31)
El límite altitudinal del bosque continuo corresponde en los Andes del Norte a una compleja zona de
transición entre el bosque paramero y el páramo, y es considerado un ambiente clave para el
monitoreo de los efectos ...
A matrix model for the population dynamics of Hyptis suaveolens, an annual weed
(2009-12-08)
Hyptis suaveolens is a neotropical annual weed that invades savanna agricultural systems. Although fire, grazing and soil disturbances have been proposed to cause its local dominance, these factors have not been experimentally ...
Leaf gas exchange in canopy species of a Venezuelan cloud forest
(Biotropica 41(6): 659-664, 2009-11)
Tropical cloud forests are considered humid ecosystems with frequent cloud cover down to the ground surface. However, seasonal variation in precipitation may induce
short-term water stress. For canopy leaves, this water ...
Coupling soil water and shoot dynamics in three grass species: A spatial stochastic model on water competition in Neotropical savanna
(Ecological Modelling 220: 2734 - 2743, 2009-10-24)
Savannas are ecosystems known for their high environmental and economic value. They cover at least 20% of the global land surface and, in some cases, can act as a boundary between tropical rainforest and deserts.Water is ...
Low temperature resistance in saplings and ramets of Polylepis sericea in the Venezuelan Andes
(Acta Oecologica 35(5): 610–613, 2009-10)
The frequent occurrence of all year-round below zero temperatures in tropical high mountains constitutes a most stressful climatic factor that plants have to confront. Polylepis forests are found well above
the continuous ...
Interception of water by pastures of Pennisetum clandestinum Hochst. ex Chiov. and Melinis minutiflora Beauv
(Agricultural and Forest Meteorology 149: 1616-1620, 2009-10)
The conversion of montane cloud forests into pastures for grazing cattle is the main cause of important impacts on rivers and streams in most of the Andes. In order to evaluate the effects of vegetation changes we need to ...
Sensitivity of soil restoration indicators during paramo succession in the high tropical Andes: chronosequence and permanent plot approaches
(Restoration Ecology 17(5): 619-628, 2009-09)
The aim of this study was to analyze indicators of soil restoration during secondary succession in a heterogeneous
valley in the high tropical Andes. A combination of chronosequence and permanent plot methods was used to ...
Un método participativo para el mapeo de fincas y la recolección de estadísticas agrícolas aplicable a varias escalas espaciales
(Interciencia 34(7): 479-486, 2009-07-28)
Se diseñó y probó un método para el mapeo participativo de fincas y la recolección de información agrícola, en el cual los
pobladores delimitan los linderos de sus fincas y realizan su sectorización interna directamente ...
Ecología comparada de Hypericum Laricifolium Juss. y de H. Juniperinum Kunth en el valle fluvioglacial del páramo de Mucubají. Mérida, Venezuela
(2009-07-15)
Hypericum laricifolium e Hypericum juniperinum son dos arbustos esclerófilos muy abundantes en hábitats parameros. Ambas especies suelen observarse coexistiendo, pero H.juniperinum parece ocupar microhábitats más húmedos ...