Termite mounds as fertility islands and their benefits for raised-field agriculture in the floodplain of the Bangweulu Basin, Zambia
Abstract
Termite mounds are conspicuous features in tropical savannas, where the role of termites as ecosystem engineers is widely acknowledged. Among the many impacts of termites on the environment, modifications of the physicochemical properties of the soil are prominent, to the point that termites have influenced the agricultural and cultural practices of local communities. However, most studies have focused on dry savannas. We investigated the role of termite mounds as fertility islands, and their role in subsistence agriculture, in one of the world’s most extensive floodplain savannas, the Bangweulu basin in Zambia. First, based on inspection of satellite images, we showed that termite savannas and areas of raised-field agriculture (the main type of subsistence agriculture in the region) covered respectively 14 % and 23 % of the studied surface area, and overlapped. Second, investigating more specifically the area near the village of Yongolo, we evidenced two superimposed patterns of spatial distribution of termite mounds, one involving large mounds (mean height 1.7 m) and one involving small mounds (mean height 0.6 m), both regularly spaced with an average inter-mound distance of 68 m and 8 m, respectively. The two types of mounds differed in their termite communities, the large ones each hosting one nest of Odontotermes, the small ones hosting mostly nests of Trinervitermes and Cubitermes. Both mound types had soil properties that differed from those of the basin soil, leading to an expected increase in soil fertility on mounds (higher contents of N, C, organic matter and clay). Woody plants, including trees, occurred only on large mounds. On small mounds, the epigeal structure of termite nests was higher where depth of flood water was higher, showing plasticity in nest construction in response to environmental constraints. Termite mounds were extensively used by local people, in particular as preferred plots for building raised fields for cassava cultivation. Raised fields on termite mounds were richer in nitrogen and clay, but had a thinner layer of dark soil, than those off termite mounds. The main benefits of building raised fields on termite mounds appeared to be a longer duration of the cultivation period (allowing cultivation during the inundation period) and increased soil fertility through weathering of termite nest structures. Termite mounds (as fertility islands) and raised fields (built by piling up topsoil) both result in nutrient concentration. In addition, both termite nests and raised fields are built taller where flooding is deeper. Thus, termites and humans rely on analogous strategies to mitigate constraints in seasonally flooded savannas, showing convergence in niche construction.
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BibTeX
@misc{blatrix2026termite,
title = {{Termite mounds as fertility islands and their benefits for raised-field agriculture in the floodplain of the Bangweulu Basin, Zambia}},
author = {Rumsaïs Blatrix and Océane Bartholomée and Mashuta Kalebe and Sesele Sokotela and Mélisse Durécu and Doyle McKey},
howpublished = {HAL},
year = {2026},
month = oct,
url = {https://hal.science/hal-05625756v4},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Termite mounds as fertility islands and their benefits for raised-field agriculture in the floodplain of the Bangweulu Basin, Zambia
AU - Rumsaïs Blatrix
AU - Océane Bartholomée
AU - Mashuta Kalebe
AU - Sesele Sokotela
AU - Mélisse Durécu
AU - Doyle McKey
PY - 2026
DA - 2026/10/14
PB - HAL
UR - https://hal.science/hal-05625756v4
AB - Termite mounds are conspicuous features in tropical savannas, where the role of termites as ecosystem engineers is widely acknowledged. Among the many impacts of termites on the environment, modifications of the physicochemical properties of the soil are prominent, to the point that termites have influenced the agricultural and cultural practices of local communities. However, most studies have focused on dry savannas. We investigated the role of termite mounds as fertility islands, and their role in subsistence agriculture, in one of the world’s most extensive floodplain savannas, the Bangweulu basin in Zambia. First, based on inspection of satellite images, we showed that termite savannas and areas of raised-field agriculture (the main type of subsistence agriculture in the region) covered respectively 14 % and 23 % of the studied surface area, and overlapped. Second, investigating more specifically the area near the village of Yongolo, we evidenced two superimposed patterns of spatial distribution of termite mounds, one involving large mounds (mean height 1.7 m) and one involving small mounds (mean height 0.6 m), both regularly spaced with an average inter-mound distance of 68 m and 8 m, respectively. The two types of mounds differed in their termite communities, the large ones each hosting one nest of Odontotermes, the small ones hosting mostly nests of Trinervitermes and Cubitermes. Both mound types had soil properties that differed from those of the basin soil, leading to an expected increase in soil fertility on mounds (higher contents of N, C, organic matter and clay). Woody plants, including trees, occurred only on large mounds. On small mounds, the epigeal structure of termite nests was higher where depth of flood water was higher, showing plasticity in nest construction in response to environmental constraints. Termite mounds were extensively used by local people, in particular as preferred plots for building raised fields for cassava cultivation. Raised fields on termite mounds were richer in nitrogen and clay, but had a thinner layer of dark soil, than those off termite mounds. The main benefits of building raised fields on termite mounds appeared to be a longer duration of the cultivation period (allowing cultivation during the inundation period) and increased soil fertility through weathering of termite nest structures. Termite mounds (as fertility islands) and raised fields (built by piling up topsoil) both result in nutrient concentration. In addition, both termite nests and raised fields are built taller where flooding is deeper. Thus, termites and humans rely on analogous strategies to mitigate constraints in seasonally flooded savannas, showing convergence in niche construction.
ER -