Anthropogenic supply of nutrients in a wildlife reserve may compromise conservation success

• Published in: Biological conservation Vol. 284; p. 110149
• Main Authors: Abraham, Andrew J., Duvall, Ethan S., le Roux, Elizabeth, Ganswindt, Andre, Clauss, Marcus, Doughty, Christopher E., Webster, Andrea B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023
• Subjects: body condition; Carrying capacity; conservation areas; ecosystems; environmental impact; fecundity; habitat destruction; herbivores; Kalahari; Kalahari Desert; mammals; Mineral lick; nutrient intake; Nutrition; phosphorus; population growth; sodium; species; Supplemental feeding; wildlife; Wildlife management; zinc; Kalahari Desert; Carrying capacity; Nutrition; Kalahari; Wildlife management; Mineral lick; Supplemental feeding
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/j.biocon.2023.110149

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. [Display omitted] •Mineral licks are commonly used by wildlife managers.•Impacts of licks on large herbivore nutrition and behaviour is poorly understood.•Larger-bodied species disproportionately consume licks, acquiring benefits.•Anthropogenic licks may inflate herbivore populations beyond carrying capacity.•Wildlife managers should cautiously consider provision of mineral licks.