No abstract

In nutrient-poor wildlife reserves it has become common-place to provide supplemental mineral resources for wildlife. Yet, the impacts of anthropogenic mineral supplementation on community-wide wildlife nutrition, behaviour and subsequent impact on ecosystem processes remain poorly understood. Here, we examine the contribution of anthropogenic mineral lick provision to wildlife nutrient intake across a community of large mammals (>10kg) in the southern Kalahari Desert. Based on predicted daily nutrient requirements and a faecal nutrient assessment, large herbivores appear deficient in phosphorus (P), sodium (Na) and zinc (Zn). For these nutrients, anthropogenic salt and mineral licks constitute an important (>10%) source of nutrient intake helping to reduce or overcome requirement deficits. Larger-bodied species disproportionately consumed licks (p<0.01), acquiring more nutritional benefits. A comprehensive assessment of animal body condition indicated that in general large herbivores display good health. However, bulk grazers, hindgut fermenters and females were more likely to display signs of malnourishment. We discuss how provisioning of anthropogenic mineral licks may be inflating large herbivore populations beyond the long-term carrying capacity of the reserve, with subsequent impacts for ecosystem integrity and herbivore population instability. Based on results presented here, it is clear that anthropogenic provision of mineral licks should be considered carefully by wildlife managers aiming to conserve or restore natural processes in conservation and rewilding landscapes.

Ecological restoration is critical for climate and biodiversity resilience over the coming century. Today, there is strong evidence that wildlife can significantly influence the distribution and stoichiometry of elements across landscapes, with subsequent impacts on the composition and functioning of ecosystems. Consequently, any anthropogenic activity that modifies this important aspect of zoogeochemistry, such as changes to animal community composition, diet, or movement patterns, may support or hinder restoration goals. It is therefore imperative that the zoogeochemical effects of such anthropogenic modifications are quantified and mapped at high spatiotemporal resolutions to help inform restoration strategies. Here, we first discuss pathways through which human activities shape wildlife-mediated elemental landscapes and outline why current frameworks are inadequate to characterize these processes. We then suggest improvements required to comprehensively model, validate, and monitor element recycling and redistribution by wildlife under differing wildlife management scenarios and discuss how this might be implemented in practice through a specific example in the southern Kalahari Desert. With robust ecological forecasting, zoogeochemical impacts of wildlife can thus be used to support ecological restoration and nature-based solutions to climate change. If ignored in the restoration process, the effects of wildlife on elemental landscapes may delay, or even prevent, restoration success.

No abstract

Sodium (Na) plays a critical role in the functioning of terrestrial ecosystems. In Na‐poor regions, plant consumers may experience Na deficiency and adapt by seeking supplementary Na resources. This can markedly impact animal behavior, space‐use, and co‐existence, with concomitant impacts on ecosystems. Many studies have noted that Na‐seeking behaviors, such as soil consumption from mineral licks, are predominately observed for larger‐bodied herbivores. However, the mechanisms that drive interspecific variation in Na deficiency and mineral lick use remain poorly understood. Here, we examine whether allometric scaling of Na requirements can explain variation in mineral lick use by herbivorous and omnivorous mammals. We 1) collated data from published literature to derive an allometric scaling of Na requirements in mammals, 2) compared predicted Na requirements to estimated Na intake of mammal communities in three globally distant sites: the Peruvian Amazon, Kalahari Desert, and Malaysian Borneo and 3) examined the relationship between predicted Na deficiency and mineral lick use utilizing camera‐trap and mammal abundance data at each site. We found that minimum daily Na maintenance requirements in mammals scaled allometrically at a higher factor (BM0.91 (CI: 0.80–1.0)) than that of food and water Na intake (BM0.71–0.79), indicating that larger species may be more susceptible to Na limitation. This aligned with a positive association between mineral lick use and body mass (BM), as well as Na deficiency, by species at all sites, and increased artificial salt and mineral lick consumption by larger‐bodied mammals in the Kalahari. Our results suggest that larger herbivores may be more sensitive to anthropogenic impacts to Na availability, which may alter their functional roles in ecosystems, particularly in Na‐poor regions. Further research is needed to explore the consequences of changing Na availability on animals and ecosystems, as well as advance our understanding of Na physiology in mammals.

No abstract

Human-wildlife conflicts on farms and ranches are common and well-documented, particularly with apex predators. Predation of livestock, for example, can result in serious economic burdens for farmers and can become threats to wildlife populations as farmers take action to eliminate or displace populations. Among apex predators, bald eagles (Haliaeetus leucocephalus) have received increased media attention in recent years due to conflicts with farmers across the United States. This raises challenges for both farmers and wildlife managers as eagle abundance continues to increase and natural prey resources decline. Interestingly, a recent study in northwestern Washington State reported high eagle activity on dairy farms in response to declines in salmon carcass availability, an important resource for wintering eagles across western North America. Despite the potential for human-wildlife conflict in these areas, little is known of the relationship between eagles and dairy farms. In this study, we investigated the extent of eagle activity on dairy farms and the relationship between eagles and dairy farmers using semistructured interviews with dairy farmers. We found that (1) eagles were attracted to dairy farms to feed primarily on cow afterbirth and calf carcasses, (2) responding farmers had no issue with the presence of eagles on their farms, and (3) many dairy farmers felt that eagles provided services to their farms. Of these services, the most recognized were scavenging of dairy farm byproducts and removal or deterrence of unwanted pest species. Increased eagle abundance on dairy farms and the subsidy of anthropogenic resources may also influence the ecological role of eagles as top predators in agroecosystems. Ultimately, farmers' decisions to provide anthropogenic resources have apparently mitigated human-eagle conflict while potentially reducing top-down pressures on other wild prey species. Farmers and wildlife managers may each benefit through cooperation in continuing to understand the intricacies of dairy farm-eagle relationships.