Efecto borde en la diversidad de termitas (Infraorden: Isóptera) en un bosque de galería de Cabuyaro, Meta

Abstract

The gallery forests of the Colombian altillanura are a refuge for fauna and flora and are associated with a wide range of ecosystem services. Land-use change generated by human activities such as livestock farming, overuse, conversion to agriculture, fragmentation and illegal logging have led to the degradation of gallery forests in the Orinoquia region on different scales. Termites (Insecta: Blattaria: Isoptera) are sensitive to alterations in soil and habitat and therefore are used as bioindicators for the monitoring of changes in environments degraded by land use. In this work, the changes in the diversity of isoptera were estimated as a function of the distance to the edge (0-20 m, 20-40 m, 40-80 m and more than 80 m) in a gallery forest located in Cabuyaro, Meta. In each category of distance to the edge, structural variables of the forest (basal area and density of silts and broadleavings, canopy cover) and physicochemical variables of the soils in the surface layer of soil monoliths were measured. The termites were collected by adapting the transect methodology, in epigean nests and trees, in pieces of wood in contact with the soil and in soil monoliths. The effective number of species (q0, q1, q2) was compared between distance categories and the possible relationship between environmental, soil and termitofauna variables was estimated by a multidimensional non-parametric scaling analysis (NMDS). The termitofauna was composed by species of 3 families, 21 genera and 40 morphospecies. The effective number of isoptera species decreased at greater distance to the edge. Structural variables such as canopy and soil coverage such as the Ca/Mg ratio, exchangeable acidity, CICE, K, Mg/K, SAI and Ca, water available for plants, the point of permanent wilt and the content of C and N showed variations with respect to the distance from the edge. In this work, xylophagous species of the genera Microcerotermes, Heterotermes and Nasutitermes presented affinity with the inside of the forest.