Range site and condition effects on “escamoles” ant (Liometopum apiculatum Mayr) nest density

Abstract The aim of this work was to evaluate the effect of rangeland condition on the nest density of escamoles ant (Liometopum apiculatum) in three different range sites, all Twithin a single (escamoles) collecting area divided into two contrasting use and property regimes, communal and private, in the Municipality of Charcas, San Luis Potosi, Mexico. In order to measure the vegetation, a point-centered quarter method along transects was used; in every quadrant the distance from the point to the closest plant was measured for each vegetation stratum, while the distance to the closest nest (if existing) was also recorded. The species recorded were grouped according to their forage value as desirable, less desirable and undesirable, and using their density and volumetric biomass estimations, these groups were compared through a tabular and descriptive statistical analysis. The soil surface state was evaluated with the line intercept method, in its proportion of live and dead (mulch) basal cover, bare soil, stones, ant trails and feces. The highest density of ant nests (14•ha-1) was recorded in the favorable site of the ranch (best rangeland condition). Marked differences were found in nest density between adjacent rangeland sites, which in turn were severely altered by the condition of these rangelands.