Abstract:
In nutrient-poor wildlife reserves it has become common-practice to provide supplemental mineral resources for
wildlife. Yet, the impacts of anthropogenic mineral supplementation on large herbivore nutrition, behaviour, and
subsequent impact on ecosystem processes have received little attention. Here, we examine the contribution of
anthropogenic mineral lick provision to wildlife nutrient intake across a community of mammalian herbivores
(>10 kg) in the southern Kalahari Desert. Based on predicted daily nutrient intake and a faecal nutrient
assessment, many large herbivore species appear deficient in phosphorus (P), sodium (Na), or zinc (Zn). For these
nutrients, anthropogenic salt and mineral licks constitute an important source of nutrient intake helping to
reduce or overcome requirement deficits. Larger-bodied species disproportionately consumed licks, acquiring
more nutritional benefits. A comprehensive assessment of animal body condition indicated that, in general, large
herbivores display good health. However, bulk grazers, non-ruminants and females displayed poorer body
condition. We discuss how provisioning of anthropogenic mineral licks may inflate large herbivore populations
beyond the long-term carrying capacity of the reserve by decoupling wildlife fecundity from nutrient-related
feedbacks on population growth. Over time, this could compromise ecosystem integrity through habitat
degradation, modified species interactions and trophic cascades. Based on results presented here, it is clear that
anthropogenic provisioning of mineral licks should be considered cautiously by wildlife managers aiming to
conserve natural processes in landscapes.
