Ant diversity and its relationship with vegetation and soil factors in an alluvial fan of the Tehuacán Valley, Mexico

In this study, we analyze the ant community found along an alluvial fan located in the Tehuacán Valley, central Mexico. Considering that this fan is composed of four terraces with different soils and vegetation structures, our main goal was to determine whether there are significant differences in ant diversity among terraces. To accomplish this goal, we determine species richness and abundance in order to calculate diversity and evenness indices. In addition, we classify species in different feeding guilds to evaluate whether differences among terraces exist. We expected higher ant diversity and variety of food guilds in terraces with sandy soils and complex vegetation structures than in terraces with argillic and calcic horizons. Correlations between several diversity parameters, and soil percent-sand and vegetation structure were also conducted. A total of 26 ant species were recorded along the fan. Species richness was not different among terraces whereas abundance was higher in sandy soils and on terraces with complex vegetation structure. Particularly, the abundance of the harvester ant Pogonomyrmex barbatus was higher in these terraces decreasing total ant diversity and evenness. Species richness within feeding guilds was similar among terraces with the generalized foragers as the most common. Our work suggests that percentage of sand in the soil and complexity of vegetation structure of the alluvial fan studied might be influencing ant distribution and favoring the abundance of numerically dominant species which could be affecting the diversity patterns of the whole community.