El Parque Cueva de los Guácharos fue el primer parque nacional declarado en Colombia y, a pesar de su estratégica ubicación, poco se ha publicado sobre la biodiversidad del parque. Este estudio exploró la diversidad de los ensamblajes de aves en diferentes tipos de bosques (andinos, subandinos mixtos y subandinos de roble negro) y el estado de sucesión, que incluye bosques subandinos primarios y secundarios. Para ello, se realizaron puntos de conteo a lo largo de transectos, durante 382 días, entre los años 2005 y 2009. En este muestreo se reportan 202 especies de aves, representando 39 familias. Las comunidades de aves de los bosques subandinos presentaron mayor diversidad y similitud entre sí, independiente de su estado sucesional. La composición fue diferente en los bosques andinos (dominados por roble blanco, Quercus humboldtii) y de roble negro (dominados por Colombobalanus excelsa, Wettinia fascicularis y Motudaea colombiana). Por ejemplo, la especie dominante en los bosques andinos fue Colaptes rivolii y en los bosques de roble negro fue Zimmerius chrysops. Para los bosques subandinos, tanto primarios como secundarios, se compartieron varias especies en la lista de las más frecuentes: Henicorhina leucophrys, Rupicola peruvianus, Ocreatus underwoodii, Hypopyrrhus pyrohypogaster y Cyanocorax yncas. Este estudio resalta la alta diversidad de los bosques subandinos, incluyendo bosques secundarios cercanos a bosques primarios protegidos. Esperamos que este trabajo sirva de base para el monitoreo futuro de comunidades de avifauna en el parque.

Estimates on population density were made for 24 species.of mammals and 5 species ofbirds, all of relatively large body size (> 45 cm long), during 13 months at Tinigua National Park, Colombia. These estimates were made using a variation of the line transect sampling method. The primates were the most abundant group in the study area in terms of individuals per Krn2. In terms ofbiomass, Tayassu, Tapirus and Mazama were also important. Temporal variation in the estima tes was found (> 20% for all species), and this seems to be related to changes in habitat use. In spite of these variations, the density estimates found for four primate species were very el ose to those found using data oflong term studies (number of individuals per group and home range). Therefore, it is proposed that the method used could be appropriate to estímate population densities for sorne species.

We determined the seed dispersa] rate of two species of Spondias (S. mombin and S. venulosa) by woolly monkeys at Tinigua National Park, Colombia. Focal sampling was used to quantify the dispersa] pattems during one year. Woolly monkeys disperse seeds of S. mombin more frequently than seeds of S. venulosa (11.2 vs. 0.4 seeds per hour of fruit consumption). In order to find out if differences in shape were correlated with the differences in dispersa] rates of the two species of seeds, we compared severa] morphological features of a sample of 587 seeds and 65 whole fruits, belonging to a total of 23 individualtrees. As seed. width was differerit in the two species; on average, seeds of S. venulosa were wider thanS. mombin seeds. Additionally, a sample of seeds collected frorn the rnonkey's feces indlcated that, on average, seeds dispersed by the rnonkeys are ·srnaller than those available in the forest. The rnorphological differences between the fruits and seeds of the two species of Spondias. are rtpt Iikely to be dlie to .allornetric relationships. The interspecific variation was srnaller than that found between trees of the same species, suggesting a high heritable cornponent in the rnorphological cháracteristics Then, it is possible that woolly rnonkeys in this cornrnunity put a significant selective pressure on the fruit rnorphology of Spondias species. Given their dispersa! patterns, probably they are affecting also the population densities of the plants. Further work on the effect of woolly rnonkeys and other dispersa! agents on the reproductive success of the dispersed is necessary to conf"mn our interpretations.

Los bosques tropicales son los ecosistemas más diversos del planeta y aunque se han propuesto muchas teorías para explicar su riqueza, aún desconocemos gran parte de la importancia relativa de los factores que la afectan. Esta diversidad se encuentra amenazada por alteraciones de origen antrópico, como la fragmentación y la degradación de los bosques. En este estudio se comparan patrones de diversidad de epífitas en un bosque de tierras bajas y uno subandino. De esta manera, se encontró una mayor diversidad de epífitas en el bosque subandino (PNN Cueva de los Guacharos) comparado con el de tierras bajas (reserva Palmarí). Adicionalmente se encontró mayor abundancia de epífitas en los bosques más conservados. Dado que la diversidad de forofitos es mayor en el bosque de tierras bajas que en el subandino, se descarta la posibilidad de que las diferencias en los patrones encontrados se den por efectos regionales de diversidad de plantas. Se concluye que la humedad parece ser el filtro ambiental más importante para explicar la variación en diversidad de epífitas.

titulo en ingles:  Structure and diversity of riparian forests in a seasonal savanna of the Llanos Orientales Colombianos (Tomo Grande Reserva, Vichada)RESUMEN:  Los bosques de galería de los Llanos Orientales colombianos son importantes reservorios de biodiversidad a nivel mundial, como resultado de la poca superficie ocupada y de su alta heterogeneidad estructural y funcional. Sin embargo, hasta la fecha no se reportan parcelas permanentes de una hectárea sobre bosques de galería de sabanas estacionales de los Llanos Orientales colombianos. En este estudio se muestra la información de la diversidad y estructura de la vegetación de tres hectáreas de bosques de galería maduros asociados a tres cursosde agua que desembocan en el río Tomo (ReservaTomo Grande, municipio de Santa Rosalía, departamento de Vichada),  analizando la diversidad (alfa de Fisher) y fisionomía (estructura vertical, índice de valor de importancia IVI, volumen de madera por clases diamétricas), y además la relación entre el diámetro a la altura del pecho (DAP) y la altura total para los individuos muestreados exceptuando palmas. Se incluyeron árboles, hemiepífitas y trepadoras con DAP mayor o igual a 10 cm. En total se encontraron 120 especies, y una diversidad baja en comparación con parcelas de la Amazonía (D-Fisher promedio=27,0), lo que se relaciona con la menor área ocupada por los bosques de galería en relación con grandes bloques amazónicos. Sin embargo, las familias más abundantes (Arecaceae, Annonaceae, Rubiaceae, Bignoniaceae, Moraceae, Burseraceae, Fabaceae, Chrysobalanaceae, Euphorbiaceae y Lauraceae) coinciden con las familias más abundantes de parcelas iguales o mayores a una hectárea de la Amazonía, a excepción de Bignoniaceae, lo que muestra la similitud entre la flora llanera y amazónica. La mayor parte de las especies mostró una dominancia local (alto IVI), en comparación con parcelas realizadas sobre otros bosques de galería y el Amazonas, lo que indica que a pesar de la cercanía, podrían existir diferencias  biogeográficas, climáticas, geológicas y/o bióticas que afectan el reclutamiento de especies.Palabras clave: Orinoquía, Parcelas permanentes, Diversidad, IVI, Composición.ABSTRACT:  Gallery forests of the Colombian Eastern Plains are important reservoirs of global biodiversity as a result of the small area occupied and its high structural and functional heterogeneity. However, to date there are no one- hectare permanent plots reported in the gallery forests of the seasonal savannas of the Colombian Eastern Plains. This study provides information about the diversity and vegetation structure of three hectares of mature gallery forests associated to three waterways that flow into the Tomo River (Tomo Grande Reserve, municipality of Santa Rosalia, department of Vichada), through the analysis of diversity (Fisher's alpha) and physiognomy (vertical structure, the importance value index IVI, timber volume by diameter class) and also the relation between the diameter at breast height (DBH) and total height for the individuals measured except palms. We included trees, vines and hemiepiphytes with DBH greater than or equal to 10 cm. A total of 120 species were found, and a low diversity compared with Amazon plots (D-Fisher mean=27.0), which is related to a reduced area occupied by gallery forests in relation to largeAmazon blocks. However, the most abundant families (Arecaceae, Annonaceae, Rubiaceae, Bignoniaceae, Moraceae, Burseraceae, Fabaceae, Chrysobalanaceae, Euphorbiaceae and Lauraceae) match the most abundant families of Amazon plots, except for Bignoniaceae, fact that shows the similarity between the Llanos and the Amazonian flora. Most species showed local dominance (high IVI), compared with plots placed on other gallery forests and in the Amazon, which indicates that despite the closeness, there may be biogeographic, climatic, geologic and biotic differences that may affect the successful recruitment of species in each area.Key words: Orinoco, Permanent plots, Diversity, IVI, Composition.

An intensive study ofseed dispersa! by woolly monkeys (Lagothrit /agotriclza) was made at Tinigua National Park, Colombia. The feeding time in different fruit species recorded o ver focal animals. The number of seeds of each species found in depositions and the spatiallocation of feces was also noted. Results show that woolly monkeys play a majar role in seed dispersa!, because they defecate intact seeds of most of the fruit species consumed. Further indications. that woolly monkeys act as efficient dispersa! agents are their prolonged retention time through the digestive tract, their extensive use of the home range, the large number of depositions with one or two seeds per species and the fact that dispersed seeds are capable to germinate.

It is very difficult to measure the seed shadows generated by animal vectors, especially when they are very mobile, but the knowledge of these seed shadows is essential to understand plant demographic processes. For this reason several authors have tried to use different methods to estimate seed shadows, using parameters such as passage rates through the gut and some approximation to asses ranging behavior. In some cases data on passage rates can be obtained from captive animals. Information from captive woolly monkeys with field data was combined, in order to generate models to predict straight dispersal distance, and also to assess the influence ofseed size and diet type on passage rates. Small plastic beads and large seeds were added to the food of four animals at the “Jaime Duque” Zoological Park, near Bogotá, which were recovered afterwards to  estimate passage rates. Longer retention times were found for small  “seeds” than for larger seeds, and in general shorter retention times were associated with a diet based on fruits, in contrast to a more fibrous diet. Passage rates in captivity were about twice as long as those in the field.  Finally, eight models to predict dispersal distance from information on passage rates and ranging patterns were formulated, combining data from the captive study and data from the field (CIEM, Tinigua Park, Colombia). The models that best fit the empirical data were those that include the distribution of distances from the field ranging patterns, while the models assuming linear progression of the animals did not fit the observed patterns. Passage rate seems to be a parameter of secondary importance to predict seed dispersal distance for our study population.

The duration of feeding bouts on fruiting trees by animal dispersers may have an effect on seed dispersal effectiveness. In this study we quantified seed removal rates and visit duration for different animal vectors in three trees of Henriettellafissanthera (Melastomataceae). The main purpose was to describe seed removal rates by different dispersers, ánd test the associatiop. of three characteristics of the dipersors that ha ve been proposed to affect bout duration times: crypsis, diet and gut capacity. We observed three primate species and 24 bird species ingesting fruits during a period of 85 h. H. fissanthera fruits correspond to the birdE dispersal syndrome, and they removed the majority of seeds, although primates removed a significant proportion offruits (40%). The largest tree was visited more often than the medium and small trees. Our results indicated that neither crypsis or diet were associated with the average duration of feeding bouts. Probably these results can be explained by the fact that the frugivories are not very exposed to aerial predators when feeding on H. fissanthera fruits, and because particular fruit preferences by frugivories seem to be very important in determining visit times. We found a positive association between average visit time and body weight (as a surrogate variable for gut capacity), but this correlation was not significant, suggesting that other factors may be more important deterrnining the duration of feeding bouts in this plant species ( e.g. instantaneous fruit abundance, tree distribution and interspecific aggressions ).