A quick glance across the countryside of the northern 3 states of Australia (Western Australia, Northern Territory, and Queensland) and you are likely to see large earthen mounds dotting the landscape. Ranging from barely above ground level to an impressive 6 meters tall (~18 feet), these mounds are the construction results of one of several species of termite, smaller conical ones from Magnetic Termites (Amitermes meridionalis) or the massive buttressed cathedrals from Spinifex Termites (Nasutitermes triodiae). Unlike their cousins that are pests to homes globally due to their consumption of dead wood – the Spinifex termites’ diet consists entirely of grasses found near the mound.
The mound serves several keys functions to the life cycle of a termite colony and from the perspective of the termite – the mound is basically a refuge from predators that serves as a place to raise young. Inside the mound is a complex network of tunnels with several large ventilation shafts that run vertically to the actual nest chamber, which is found below the surrounding soil surface. The multiple tunnels and earthen construction provides shelter from outside environment, making the temperature and humidity stable inside the mound. Due to often being made of clay the mounds themselves are fire resistant, a frequent threat during the dry season in the open forests and grasslands that span northern Australia.
Despite the obvious impact mound construction has on the local environments (a large clay object dotting the landscape) – there are some other surprising effects the mound building termites have as well. Plant communities directly on and near the mound are considerably different than those further away from the mounds, both in species compositions and in functional groups. Despite it serving as a shelter – it is thought that termite colonies cease to exist after the queen dies, leaving only the mound behind. Many other species of animals make use of the now vacant mound, including reptiles, small mammals, and marsupials. Empty mounds are even a predictable enough resource, that several species of bird only make their nests in the abandoned termite mounds! One of these is the Golden-shouldered Parrot (Psephotus chrysopterygius), a species once found over most of the Cape York Peninsula but has been reduced to under 1500 individuals in all of Australia.
Mound building termites are truly ecosystem engineers, having a profound impact on the local ecosystems by creating a novel environment. It is through the construction of the mounds the termites provide habitat and food resources for many other species during and after habitation by the actual termites. Indeed northern Australia is an enormous region shaped and managed by a tiny insect.