Spatial and temporal abundance of mycelial mats in the soil of a tropical rain forest in Mexico and their effects on the concentration of mineral nutrients in soils and fine roots.

• Here, we investigated the spatial and temporal abundance of mycelial mats in a tropical rain forest to determine their effects on the concentration of mineral nutrients in soils and fine roots. • Mats were marked and followed over three seasons. Fine-root mass and the concentration of mineral nutrients in both soils and roots were determined for mat-associated soils and for a control group. • Mats were more abundant in the dry season than in the wet season. The concentration of mineral nutrients in soils and fine roots increased from the rainy season to the end of the dry season. Mats appeared to affect the concentration of phosphorus, potassium and calcium, and the carbon : nitrogen and nitrogen : phosphorus ratios in soils and roots during all seasons. • Mats appeared to compete with plants for certain minerals. This could be part of ‘bottom up’ effects that may influence underground herbivory, as well as the above-ground concentrations of mineral nutrients in plants. Mats are relevant to understanding soil biodiversity and the potential feedback paths between the soil and above-ground subsystems. © New Phytologist (2004) doi: 10.1111/j.1469-8137.2004.01099.x [ABSTRACT FROM AUTHOR]