Context-dependent directional effects of termite mounds on soil nutrients, vegetation communities, and mammalian foraging
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Date
Authors
Davies, Andrew Byron
Levick, Shaun R.
Janse Van Rensburg, Berndt
Robertson, Mark P.
Parr, Catherine Lucy
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
Termite mounds are keystone structures in African savannas, affecting multiple ecosystem processes. Despite the large size of termite mounds having the potential to modify conditions around them, patterns of mound-induced ecosystem effects have been assumed to be isotropic, with little attention given to how effects might vary around mounds. We measured soil nitrogen content, grass species composition, and mammalian grazing on and off termite mounds in the four cardinal directions, and across wet and dry seasons at three savanna sites varying in mean annual rainfall in South Africa's Kruger National Park. Evidence of directional effects (anisotropy) on ecosystem properties around termite mounds varied with site. Grass species composition differed between north- and south-facing slopes at the two drier sites where mounds were taller. However, differences in grazing extent and soil nitrogen content around mounds were only present at the intermediate rainfall site where mammalian herbivore biomass was highest, and mounds were of medium height. Our results suggest that termite mound effects display significant variation with direction, but that the emergence of directional effects is context dependent. Our results further suggest that such context-dependent directional effects can lead to positive feedback loops between termites, abiotic conditions, and mammalian herbivores.
Description
DATA AVAILABILITY STATEMENT :
Data (Davies, 2024) are available from Figshare: https://doi.org/10.6084/m9.figshare.26340679.
Keywords
Anisotropy, Aspect, Feedback, Grazing, Kruger National Park (KNP), Kruger National Park (South Africa), Macrotermes, Savanna, Soil nutrients, Termites, SDG-15: Life on land
Sustainable Development Goals
SDG-15:Life on land
Citation
Davies, Andrew B.,
Shaun R. Levick, Berndt J. van Rensburg, Mark
P. Robertson, and Catherine L. Parr. 2024.
“Context-Dependent Directional Effects of Termite
Mounds on Soil Nutrients, Vegetation
Communities, and Mammalian Foraging.”
Ecosphere 15(9): e4978. https://doi.org/10.1002/ecs2.4978.