Ecology and Conservation of the
Forest Canopy in the Colombian Andes
(Study of Epiphytes, Birds and Insects).

For this project, the sequestration and storage of carbon were quantified in Canopy trees along with their epiphytes in a fragment of a cloud forest where oak trees - Quercus humboldtii represent the largest part of the whole forest. It was found that each of the components of the epiphyte-host tree system shows different percentages of C concentration. In the case of the Oak trees, it was found that the branches with diameters lower than 5 cm. have the largest capacity in capturing C (40.13%), followed by the wood contained in the trunk and in branches with diameters higher than 5 cm. Those present a lower percentage (38.75%). Fresh leaves and dead leaves show 35.95% and 34.05% of C retention respectively. In the case of epiphytes growing on these trees, it was discovered that the lichens and bryophytes yielded a 43% of C, being the component with more capacity of retention of C in the epiphyte – host tree system; the bromeliads had a capacity of 38.82% also presenting a bigger capacity of capture of C than that of the components of their host tree, excepting the superior branches. As for the C stored in the biomass it was found that in the four evaluated trees and their epiphytes, there was 32066 kg in 0.0938 ha.

Trophic community structure of resident arthropods occupying different microhabitats present in the canopy of a neotropical cloud forest – Colombia.

Héctor Gasca & Diego Higuera

Arthropods resident in the external crown from four oak canopy trees (Quercus humboldtii) were collected, with the purpose of characterizing the trophic community of arthropods that coexist in the different microhabitats of this forest stratum. The total biomass of bromeliads, lichens and bryophytes, and the rotten trunks present in the external crown of the chosen trees were quantified. The most richness and abundance of arthropods per biomass unit was found in the lichens and bryophytes where the Collembola accounted the majority of the arthropods In 0.0938 ha, which corresponded to the cover of the four trees, it was found that the lichens and bryophytes represented most part of the biomass with 108.5 kg, the rotten trunks 104 kg, and the bromeliads 55.4 kg. The main trophic group was the decomposers with the 48% constituted by saprophagous, xylophagous, and detritivores arthropods. The high number of individuals in this trophic group can be related with the high production and dynamics of organic matter in this forest, mainly by litter along the year corresponding to 15.4 ton ha-1 y-1.

Preliminary study of the trophic structure of the community of birds and the availability of resources in the canopy of a neotropical oak forest - Colombia.

Juan Carlos De Las Casas & Diego Higuera

During almost a year sporadic observations were carried out of birds foraged in the external crown in a forest of oak trees (Quercus humboldtii) in the department of Cundinamarca, Colombia to 2650 m. The information obtained was compared with the data obtained as for the abundance of arthropods and present biomass in this stratum in a study advanced by Corporación Sentido Natural. 28 species of birds were registered, inside which the most important guild in the canopy were the insectivorous birds represented by the 100%, although some of these birds also presented frugivorous habits or other in some measure. The high number of insectivorous birds in the canopy is product of the abundance of arthropods that reside in the lichens, bryophytes, bromeliads and trunks in decomposition in the external crown and of insects that fly over in the canopy. The resource that more the birds foraged were the lichens and the bryophytes of the bark where a great number of arthropods by unit of biomass was found, being this resource the one that more biomass presented in the canopy. In spite of being a preliminary study, this work shows interesting and important data of the interactions that happen in the canopy of an oak forest in Colombia, with the objective of deepening about the matter.

Distribution of bromeliads biomass in oak canopy trees in a neotropical Colombian cloud forest.

Diego Higuera

The distribution of bromeliads biomass was studied in four Oak canopy trees (Quercus humboldtii), that where located in a neotropical cloud forest. 715 bromeliad individuals were found; species making up the community were Tillandsia biflora, Tillandsia complanata, Tillandsia denudata, Tillandsia fendleri, Tillandsia pastensis, Tillandsia restrepoana and Vriesea fragrans in an area of 0.0938 ha. corresponding to the sum of the covering of the four evaluated trees. The number of species and bromeliad individuals varied among the different trees with values that were in 5 and 6 species, and among 82 and 301 individuals. These species had a biomass of 71.85 kg, which varied among the different host trees with values that were between 6.8 kg and 39.2 kg.

Production of litterfall and its nutrient contribution by canopy oak trees (Quercus humboldtii) in a neotropical cloud forest – Colombia.

Diego Higuera & Eliana Martínez

In a cloud forest located at 2700 m in the Eastern Colombian mountain, where the dominant species in the oak (Quercus humboldtii), the fall of litterfall was determined by means of 12 collectors which were placed in two oak canopy trees to different heights, between 12 m and 22 m. It was found that in adult oak trees whose biomass of green leaves can vary between 20.52 kg 27.22 kg a fall of litterfall was present throughout all the year. The concentration of N, P, K, S and Ca were smaller in the litterfall than in tree leaves, and the Mg concentration did not vary, (Q. humboldtii) presented high concentrations of N (18.2 mg g-1) and low concentrations of P and K. Nevertheless, these two last nutrients presented a high retranslocation, which suggests that these two elements are limitants in this ecosystem.

Mist nets in the canopy, modifications for the system of curtain.

Juan Carlos De Las Casas & Diego Higuera

In this work were analyzed several methods for installing mist nets in the canopy, looking first at having the net into the really canopy, but also looking for the lowest cost, and looking to security for the researcher. The best alternative we have come up with is the one proposed by Stokes & Schultz (1995), and then later improved by Stokes et al. (2000). Nevertheless we improvised several modifications to the original model which adds more security to the design for the researcher, and, at the same time, adds comfort and easy control, saves time when opening the mist nets, and saves money in materials, improving the design structure. The changes effected made it possible to work with the mist nets without inconvenience for the researcher, and without annoyance for the birds captured. In this article we show the modifications added to the curtain-system to be used in the forest canopy, and, in addition, we explain the best way to employ and install the net.