EFECTO DE BORDE EN LA DIVERSIDAD Y COLONIZACIÓN DE ECTOMICORRIZAS DE Quercus humboldtii (FAGACEAE) EN ARCABUCO-BOYACÁ-COLOMBIA

The oak forests in Colombia are dominated by the species Quercus humboldtii Bonpl. which is in the vulnerable category due to deforestation to generate crops, livestock areas and plantations of exotic species, causing the formation of edges due to the deterioration of the ecosystem. These forests establish symbiotic associations with species of ectomycorrhizal fungi, allowing the exchange of nutrients and water between fungal hyphae and plant roots. This study analyzes the edge effect in the interior (BNI-C) and at the edge of an undisturbed oak forest (BNI-B), in addition to two forest edges with anthropogenic intervention, one in contact with a plantation of Eucalyptus sp. (BE) and another with cattle ranching (BG). The forest edge was established by measuring environmental variables (ambient temperature, luminosity, temperature, and soil humidity). Oak roots were collected from seven trees at the interior and edge of each forest and the quantification of colonization and morphological characterization of ectomycorrhizae was made. The edge effect was evidenced in the degree of ectomycorrhizal colonization in the roots of Q. humboldtii with percentages of 18 to 30 % in BNI, 15 % in BE and 47 % in BG. The ectomycorrhizal genera Cenococcum sp. and Lactarius sp. showed the highest abundance in the three forests, varying considerably near the edges in BG and BE. Changes in the percentage of colonization and morphotype diversity of ectomycorrhizae were evidenced at the forest edge in contact with the two disturbed areas.