QUANTIFYING THE FOOTPRINT OF A DOMINANT ORGANISM: IMPACTS OF LEAF CUTTER ANTS ON BIOGEOCHEMICAL CYCLING IN TROPICAL FORESTS

One of the most conspicuous features of a tropical forest is the abundance of leaf cutter ants. Their networks of trails extend throughout the forest and workers walk single-file, carrying pieces of leaves into their nests, where special fungi break down the plant material and produce hyphae, on which the ants feed. Leaf cutter ant nests are massive in size and during nest construction and maintenance, ants mix soil particles and alter soil chemistry. Leaf cutters are also the dominant herbivores in tropical forest ecosystems, bringing 10-50 % of all surrounding vegetation into the nest, fertilizing nest soils, and promoting the release of carbon dioxide into the atmosphere. Leaf cutter ant activities can therefore influence ecosystem carbon dynamics, though their influence remains unquantified. To address this knowledge gap, carbon dynamics inside leaf cutter ant nests will be compared to areas without ants. This information will be used to model how leaf cutter nests influence soil and atmospheric carbon dynamics across a range of tropical ecosystems.

Leaf cutting ants are increasing in abundance in tropical and subtropical ecosystems that cover 17% of the Earth’s land mass and store approximately 40% of all carbon, much of it in soil. The global climate is changing and of particular concern is the potential influence of climate change on soil carbon dynamics. Understanding the contribution of an ecologically important ant species helps address a critical knowledge gap in the global carbon cycle and improve predictions of future carbon dynamics.

 

Atta cephalotes nest entrance

Atta cephalotes nest entrance

Gas wells installed to collect gases from across a soil depth profile

Gas wells installed to collect gases from across a soil depth profile

Atta cephalotes soldier

Atta cephalotes soldier

Small nest entrance of recently initiated nest

Small nest entrance of recently initiated nest

Fungal chamber inside a leaf cutter ant nest

Fungal chamber inside a leaf cutter ant nest