INTROPICA

5-15

Authors: Larrys Fontalvo-Rodríguez, Cesil Solís-Medina

An ant community was studied in nine areas in the complex mining of Cerrejón Ltd. in the Cerrejón Valley (Department of Guajira-Colombia). In each site, 10 sampling stations were installed over four time periods, covering the different climatic events of the region. Ants were collected using pitfall traps, mini-Winklerbags, manual capture and Malaise traps. For the comparisons between areas, we applied non parametric estimators of richness, diversity indices and similarity coefficients. 3.935 individuals were collected in 2.652 capture events, 71 species belonging to eight subfamilies, 19 tribes and 37 genera were identified. The estimators of richness produced estimates of 73 species (ICE), 73 (Chao 1) and 77 (Jacknife 1) respectively, for the nine areas. No significant differences between the diversity values were detected. The Bray-Curtis similarity coefficient showed that the sites are not similar in relation to their richness and abundance. Each area contributed species to the total diversity of Formicidae, which suggest that they should be conserved to maintain the local and regional biodiversity.

47-53

Authors: Hernando Suárez-Gómez

Pathogenicity, mortality and lethal time of Beauveria bassiana (Bals.) Vuillemin on maize weevil, Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae) was evaluated using concentrations of 1 x 106, 1 x 107, 1 x 108 and 1 x 109 conidias/ml. The study was conducted at the Entomology Laboratory of the Magdalena University (Colombia) (temperature de 25±1ºC; relative humidity 90±2 %; and photoperiod = 1 2:12) .The fungus was isolate from Leptopharsa gibbicarina (Hemiptera: Tingidae), insect pest of oil palm. Adults of the S. zeamais were obtained from a laboratory mass rearing. The experiment was organized in a complete randomized design with four replications. These insects were exposed to the fungus using four concentrations of conidias/ml. The mortality mean was 98,37 0% for all concentrations. There were significant differences (P ≥ 0,05) among concentration and control. The minor Mean lethal time was to concentrations 1x106 conidia/ml. Results show efficient control

67-78

Authors: Ralf Strewe, Gheynner Lobatón-Polo, Cristóbal Navarro, César Vega-Sepúlveda, Carlos Villa-De León

Based on bird research, the basin of the Toribio River on the slopes of San Lorenzo Hill was declared as the first Important Bird Area (IBA) in the Colombian Caribbean region, a programme by the Alexander Von Humboldt Institute and Birdlife international. To ensure the long term protection of IBA, a conservation corridor has been devised in the basin of the Toribio River, on the North East slope of the Sierra Nevada de Santa Marta, county of Magdalena, within an altitudinal gradient which ranges from 450 to 2.600 m (above sea level), as an Interlink of Agro-forestry and natural Eco-systems mosaics. The certification programme ‘Critical Ecosystems Alliance’ (CEA), was developed as an implementation instrument of the conservation corridor, with specific conservation criterion and unique for Colombia and South America. The corridor implementation was carried out through the establishment of 34 nurseries with 61.000 planting bags and 36.000 seedlings produced from native species, timber-yielding and fruit-bearing for the bio-diversification of the agro-forestry systems and for the reforestation of the critical areas. In 34 premises the criterion was implemented handling 69 water springs, 308 ha of agro-forestry systems with a diversified shade, 101 ha of reforestation areas and 182 ha of freed areas for the habitat conservation and recovery.

93-99

Authors: Luz Adriana Velasco, Judith Barros-Gómez, Gloria Helena Ospina-Salazar, Carlos Alberto Trujillo

In order to understand the effect of light intensity, temperature and salinity on the growth in density of the microalgae Isochrysis galbana (T-ISO), a factorial experiment 2x2x2 was done under laboratory conditions. Microalgal growth was higher at high illumination (1024 lux) than at low one (24 lux). Temperature caused different effects depending on the light intensity supplied. In cultures with high illumination, bigger growth was obtained at high temperature (28°C), but in conditions of low light intensity, higher growth was presented at low temperature (22°C). Salinities between 27 and 35 did not show any effect on the growth of the microalgae.

113-119

Authors: Lennin Florez-Leiva, Alejandro Rangel-Campo, Marta Díaz-Ruíz, Dagoberto Venera-Pontón, Guillermo Díaz-Pulido

Increased rates of sedimentation in the marine environment as a consequence of increased runoff, deforestation, inappropriate agricultural practices, etc, is a matter of concern due to the negative impacts on the ecology of coral reefs. Benthic algae are amongst the most important biological components of such ecosystems, however, little is known about the impacts of sedimentation on the ecology of tropical benthic algae. In this study we explored the effects of different types of sediment on the abundance and community structure of the algae in the Tayrona National Natural Park, Colombian Caribbean. The results showed that the addition of different types of sediments (from land, river, and marine) had minor effects on the cover, diversity and community structure of the algae. The different type of sediments added did not significantly change the algal structure, however there were rare species with low abundance that occurred preferentially in specific sediment treatments. We conclude that there are a wide range of responses of algae to nature of the sediments