Colombia Forestal

8

Authors: Eloisa Lasso, Lucas Santiago Barrientos

The role of animals as seed dispersal vectors is widely acknowledged, including dispersal by reptiles (saurochory). Most reports of saurochory have been via endozoochory, through feces deposition. We present the first evidence of epizoochory in Iguanas from a dry forest in Colombia via seeds attached to the snout. Our results show that seeds of a cactus Melocactus curvispinus ingested by iguana suffers from their passage through the digestive tract while seeds transported while attached to the snout germinate faster and in higher numbers. Our data suggest that we may have overlooked an alternative means of seed dispersal by lizards that does not comprise a passage through their digestive tract, and that deserves further attention for the understanding of dry forest ecology.

11

Authors: María Cristina Gallego-Ropero & Beatriz Salguero Rivera

The ant assemblages of a fragment of secondary tropical dry forest located in the Botanical Garden of Cali are presented. Two habitats were chosen: a fragment of forest and a pasture matrix. Samples were taken monthly for six months, using a linear transect of 100 m, with 10 stations spaced 10 m. At each station pitfall traps, epigeal bait and arboreal, sifting and removal of 1 m2 of litter and manual capture survey techniques were applied. Richness, abundance and diversity of ant habitats were determined. Correlation coefficients and regression between temperature, relative humidity and richness of ants were calculated. A total of 13 170 ants representing 55 species, 35 genera and six subfamilies were collected. The forest had the highest species richness with 90.9%. This wealth of diversity indicates the conservation value of the Valle del Cauca myrmecofauna. Although the forest is in the process of regeneration, strongly disturbed by constant fire and human intervention, the ant species richness shows that it remains an invaluable source of biological resources for the conservation of species.

14

Authors: Viviana Londoño Lemos & Alba Marina Torres González

Characterization of long-term vegetation in a tropical dry forest (TDF) that is in the process of regeneration permits establishment of patterns of composition, structure and dynamics of plant communities and sheds light on the different stages of plant succession. In this study, the plant community of ecoparque Bataclán, Cali, Colombia was evaluated by determining its structure and composition in two regeneration strategies. One strategy consisted of natural regeneration with bamboo barriers and the other of natural regeneration without bamboo barriers. Three permanent plots of 500 m2 were established in each regeneration strategy (six plots in total). Composition and structure was determined, taking into account all the growth habits, with different sampling methods. We found no significant differences between vegetation structure and composition of the two strategies for forest regeneration. forty-one species belonging to 27 families were recorded (trees and shrubs 58.5 %, herbs 24.4 %, climbers or scandents 14.6 %, epiphytes 2.4 %). The dominant family was Melastomataceae and the dominant species was Miconia prasina. The orchid Catasetum ochraceum and the grass Thrasya petrosa were indicator species for high luminosity. We conclude that the plant community is in an early successional stage, where there is a mixture of planted and naturally regenerated species in the zone, characterized by pioneer species from TDF and other nearby life zones.

20

Authors: Hernando Vergara Varela

Vegetation of dry forest ecosystem of the Patia valley located in the department of Cauca has been altered and replaced by crops and pastures. The forest remnants were characterized in terms of their structure and floristic composition at altitudes between 500 and 800 m. This study evaluated changes in land cover using aerial photographs and satellite image as input to produce land cover maps in order to assess changes associated with land use types. Data were analyzed by multivariate methods using the TWINSPAN program to produce a vegetation classification, identifying six vegetation structure types and six floristic types. The floristic gradient thrown by the program describes structural types, ranging from forests to shrublands and grasslands. Successional plant communities reflect conditions of the fragments, Citharexylum kunthianum community contrasts with riparian forests determined by Eugenia sp the dominant specie in disturbed areas. Handroanthus chrysanthus community shows a transition to xerophyte vegetation of the south of Colombia. Land use types and land cover classes have remained since 1961, increasing pasture cover. Tropical dry forests are reduced in its structure, considering that forests are disturbed. In the long history of the land use and disturbance of this area, a reduction in forest fragments is evident, social and economic factors are a force for a change in plant communities in rural areas.

23

Authors: William Vargas

Information on the flora of the dry forests of southern Huila province was revised, with emphasis on intermediate pioneer species that can support processes of ecological restoration and conservation of biodiversity, these data were compared with those obtained in the field over the past 30 years. According to literature, 203 intermediate pioneer species distributed in 123 genera and 45 botanical families were identified for Huila, while for La Jagua field data recorded 155 species grouped in 111 genera and 45 families among which Leguminosae, Rubiaceae, Euphorbiaceae, Malvaceae, Melastomataceae and Moraceae are the most important families. The main types of hedges in the landscape of La Jagua are described, with notes on major plant species, conservation status and representative fauna. A list of 155 intermediate pioneer species is proposed, with the most important attributes for use in processes of conservation and ecological restoration of dry forests in the region. This type of species is key in generating habitat, connectivity, resources for wildlife and production of resources such as firewood and wood for communities, within a model of landscape management tools.