Structure and hydrology of mounds of the imported fire ants in the southeastern United States

Imported fire ants comprise two introduced species which build large mounds at high densities throughout the southeastern United States. They represent a new soil-forming factor for these soils. A study was conducted to quantify the channel network geometry, clod density, aggregate stability, and micromorphology of the mounds on three texturally different soils, and examine the moisture relationships in the mounds. The channels averaged 0.6 cm wide in mounds on a sandy loam and a silt loam, and 1.0 cm wide in a mound on a clay soil. Channels occupied 39% of the horizontal cross-sectional area in the mound on the sandy loam and 55% in the mounds on the silt loam and the clay. The interchannel matrix of the mound assembled by the ants consists of a porous, bridged-pellet framework which is separated from the channels by a thin (