Factores que influyen sobre la actividad microbiana en basureros de hormigas cortadoras de hojas

Ecologia Austral, 24:103-110 (2014) Soil microorganisms play a key role in the process of nutrient cycling. Therefore, the knowledge of the factors that influence its activity is vital for a better understanding of terrestrial ecosystem function. We use external refuse dumps from the leaf-cutting ant  Acromyrmex lobicornis  such as a model system to determine the influence of the concentration and diversity of organic matter on the activity of soil decomposers. We estimated the concentration of carbonate compounds and the respiration rate of microorganisms in samples of refuse dumps under lab conditions. We also estimated the diversity of the ant diet like a proxy of the diversity of organic compounds in their refuse dumps. The activity of microorganisms did not show association with the concentration of carbonate compounds, but showed a tendency to a positive association with the diversity of the ant diet. Since the diversity of organic matter in refuse dumps depends on the diversity of the plants harvested by ants, these results partially support the idea that the activity of soil microorganisms partially depends on the diversity of resources to decompose. This work exemplify how leaf-cutting ants affect soil properties in arid environments where the availability of organic matter is limiting, and illustrate a novel way how the reduction of vegetation diversity may indirectly affect the productivity of a system through the impoverish of the leaf-cutting ant´s diet.