From the report (link below):
"Here, we describe a vast array of soil mounds constructed by termites (Syntermes dirus) that has persisted for up to 4000 years and covers an estimated 230,000 square kilometers of seasonally dry tropical forest in a relatively undisturbed and climatically stable region of Northeast Brazil. The mounds are not nests, but rather they are generated by the excavation of vast inter-connecting tunnel networks, resulting in approximately 10 cubic kilometers of soil being deposited in 200 million conical mounds that are 2.5 m tall and approximately 9 m in diameter...
...The mean inter-mound distance is 20 m, giving mound density of 1800/sq. km, leading to an estimated 200 million mounds. Each mound is composed of approximately 50 cubic meters of soil that required the excavation of over 10 cubic kilometers of earth, equivalent to ~4000 great pyramids of Giza -- making this the greatest known example of ecosystem engineering by a single insect species...
...Inspection of hundreds of mounds bisected by road construction, supplemented by our own excavations, has revealed that each mound is simply an amorphous mass of soil without any internal structure. Newly forming mounds contain a single large (diameter of ~ 10 cm) central tunnel descending into the ground that intersects with an extensive network of underground tunnels (diameter of up to 10 cm) and narrow horizontal galleries containing harvested discs of dead leaves or brood, to date no royal chamber has been located either in or below a mound, despite extensive searching... At night, when food is available, groups of 10-50 workers and soldiers emerge onto the forest floor between the mounds from an array of small (diameter of ~ 8 mm) temporary tubes excavated from below; these temporary tubes are sealed shut after use... "
https://www.cell.com/action/showPdf?pii=...%2931287-9
https://www.cell.com/current-biology/ful...all%3Dtrue
"Here, we describe a vast array of soil mounds constructed by termites (Syntermes dirus) that has persisted for up to 4000 years and covers an estimated 230,000 square kilometers of seasonally dry tropical forest in a relatively undisturbed and climatically stable region of Northeast Brazil. The mounds are not nests, but rather they are generated by the excavation of vast inter-connecting tunnel networks, resulting in approximately 10 cubic kilometers of soil being deposited in 200 million conical mounds that are 2.5 m tall and approximately 9 m in diameter...
...The mean inter-mound distance is 20 m, giving mound density of 1800/sq. km, leading to an estimated 200 million mounds. Each mound is composed of approximately 50 cubic meters of soil that required the excavation of over 10 cubic kilometers of earth, equivalent to ~4000 great pyramids of Giza -- making this the greatest known example of ecosystem engineering by a single insect species...
...Inspection of hundreds of mounds bisected by road construction, supplemented by our own excavations, has revealed that each mound is simply an amorphous mass of soil without any internal structure. Newly forming mounds contain a single large (diameter of ~ 10 cm) central tunnel descending into the ground that intersects with an extensive network of underground tunnels (diameter of up to 10 cm) and narrow horizontal galleries containing harvested discs of dead leaves or brood, to date no royal chamber has been located either in or below a mound, despite extensive searching... At night, when food is available, groups of 10-50 workers and soldiers emerge onto the forest floor between the mounds from an array of small (diameter of ~ 8 mm) temporary tubes excavated from below; these temporary tubes are sealed shut after use... "
https://www.cell.com/action/showPdf?pii=...%2931287-9
https://www.cell.com/current-biology/ful...all%3Dtrue