Introduction
Aloe marlothii, the mountain aloe, is a large, single-stemmed succulent of southern African savannas and rocky slopes, famed for its armored leaves and broad, candelabra-like winter inflorescences. It thrives on stony or clayey substrates from the lowlands into foothills and often punctuates open, sun-baked hillsides. These same landscapes are patterned by mound-building termites whose earthworks restructure soils and microclimates. Where mounds are common, they frequently create microsites that favor establishment and long-term persistence of woody plants and large aloes, including A. marlothii.
The Details
Termite mounds are classic ecosystem-engineering structures. Fungus-growing termites excavate mineral-rich subsoils and bring nutrients up to the surface, concentrating phosphorus and other elements in stable, elevated knolls. Just as important, the maze of galleries and vents aerates the soil, creating macropores that improve gas exchange and infiltration. The mound core and apron also retain moisture and buffer extremes, so the substrate dries more slowly after rain and stays more humid than adjacent bare ground. Together, nutrient enrichment, enhanced aeration, and moderated moisture transform poor, fire-prone savannas into long-lived “resource islands” that differ sharply from the surrounding matrix.
These pedological shifts map neatly onto the needs of A. marlothii. The species tolerates clays and loams yet demands drainage and abundant sun. On and around old or eroding termitaria, seedlings can root into friable, well-aerated soils with improved access to nutrients; adults perched on mound shoulders avoid episodic waterlogging and cold-air pooling while still benefiting from the mound’s moisture buffering after summer storms. The slight elevation also lifts rosettes above fine fuels, reducing scorch during quick grass fires. Over time, repeated recruitment on these patches yields conspicuous local clustering of mountain aloes in otherwise lean terrain.
Mounds further drive biotic cascades that indirectly help A. marlothii. By boosting productivity and structural complexity, they concentrate insects and flowers and provide perches that increase bird activity. When aloes bloom in winter, these lively “islands” can amplify visits by nectar-feeding birds and insects, improving pollination—especially in landscapes where resources are patchy. Notably, termites seldom attack healthy succulent tissue; direct herbivory on living Aloe leaves is rare. Their influence is architectural and pedological: they bring deep soil upward, aerate it, and modulate its moisture, thereby building an archipelago of favorable microsites where mountain aloes can establish, mature, and, in good years, flower spectacularly above the savanna.
Additional Reading: Termites of Kruger National Park
