Humans provide supplemental food to wildlife under many contexts, ranging from professional feeding areas for game species to backyard bird feeders. Such resources benefit wildlife by providing ...reliable resources during periods of food shortages, but may also alter the risk of pathogen transmission and development of disease. While several reviews have summarized the detrimental effects of supplemental food on infection risk, we conducted a comprehensive review to quantify support for mechanisms by which intentional wildlife feeding influences host condition (i.e. malnutrition and stress) and pathogen transmission on a global scale and provide a framework to mitigate these risks. We also examined whether the purpose of feeding, whether for game management, conservation, tourism, or in residential areas, influenced health outcomes. We found 115 studies that evaluated the health of wildlife with supplementary feeding, representing 68 species in 35 countries, although nearly half (46% of studies) were from North America. Supplemental feeding tended to increase the risk of pathogen transmission by increasing contact rates between hosts (95%) and promoting pathogen accumulation at feeders or the surrounding environment (77%). Provisioned food was also often a source of immunosuppressive contaminants (80%). Feeding associated with tourism frequently increased wildlife stress, rates of injury, pathogen prevalence, or malnutrition (85%), while feeding for conservation purposes had mostly positive effects on wildlife health (63%). We recommend adopting feeding practices that validate the nutritional appropriateness of wildlife feed for the target species, make food available at lower densities for short periods at unpredictable times and places to prevent aggregation, and avoid feeding during times of migration, pulses of new recruits, and epidemics. These strategies will help retain the recreational and management benefits of wildlife provisioning while mitigating negative effects for many species around the world.
•Studies on wildlife health with provisioning spanned 68 species in 35 countries.•Feeding negatively affected health through higher contact rates, stress, and contaminants.•Provisioning by tourists was most often associated with negative health outcomes.
Urbanisation and agriculture cause declines for many wildlife, but some species benefit from novel resources, especially food, provided in human‐dominated habitats. Resulting shifts in wildlife ...ecology can alter infectious disease dynamics and create opportunities for cross‐species transmission, yet predicting host–pathogen responses to resource provisioning is challenging. Factors enhancing transmission, such as increased aggregation, could be offset by better host immunity due to improved nutrition. Here, we conduct a review and meta‐analysis to show that food provisioning results in highly heterogeneous infection outcomes that depend on pathogen type and anthropogenic food source. We also find empirical support for behavioural and immune mechanisms through which human‐provided resources alter host exposure and tolerance to pathogens. A review of recent theoretical models of resource provisioning and infection dynamics shows that changes in host contact rates and immunity produce strong non‐linear responses in pathogen invasion and prevalence. By integrating results of our meta‐analysis back into a theoretical framework, we find provisioning amplifies pathogen invasion under increased host aggregation and tolerance, but reduces transmission if provisioned food decreases dietary exposure to parasites. These results carry implications for wildlife disease management and highlight areas for future work, such as how resource shifts might affect virulence evolution.
Urban environments are novel alternative habitats for wildlife. Anthropogenic food resources such as supplemental feeding (SF) are usually abundant, stable across seasons, and sometimes rich in ...calories. Although anthropogenic food resources could modify the seasonality and composition of the diets of urban animals, previous studies have been limited to qualitative assessments based on stomach content and food remains. Our study compared diet seasonality and niche width between rural and urban populations of Eurasian red squirrels (Sciurus vulgaris) in Hokkaido, Japan, using direct observation and stable isotope analysis. We found that dietary seasonality was lower in urban populations than in rural populations. The frequency of seed use was higher throughout the year in urban populations than in rural populations, possibly because of excessive seeds by SF in urban squirrels. Additionally, female body weights of the urban population were higher than those of the rural population. However, this was not true for males. Because high body weight can increase reproductive success in females, it is feasible that diet modification could contribute to population growth in urban squirrels. However, no differences in male body weight were observed, possibly due to energy loss caused by intense male–male competition at feeding sites. Our study highlights the importance of studying the multidimensional effects of anthropogenic foods on wildlife.
Adequate nutrition supports the development of healthy honey bee colonies. We give an overview of the nutritional demands of honey bee workers at three levels: (1) colony nutrition with the ...possibility of supplementation of carbohydrates and proteins; (2) adult nutrition and (3) larval nutrition. Larvae are especially dependant on protein and brood production is strongly affected by shortages of this nutrient. The number of larvae reared may be reduced to maintain the quality of remaining offspring. The quality of developing workers also suffers under conditions of larval starvation, leading to slightly affected workers. Larval starvation, alone or in combination with other stressors, can weaken colonies. The potential of different diets to meet nutritional requirements or to improve survival or brood production is outlined. We discuss nutrition-related risks to honey bee colonies such as starvation, monocultures, genetically modified crops and pesticides in pollen and nectar.
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.
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•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.
Prior research on baiting and feeding of wildlife found changes in habitat and the concentration of wildlife on a local scale (e.g., hundreds of meters). Since changes in habitat and host density ...affect ticks, feeding wildlife may lead to changes in tick and tick-borne disease ecology. We quantified the effect of feeding deer on ticks and tick-borne diseases at 79 pairs of sites with and without deer feeders during May-August of 2019 and 2020. We captured 0.4 fewer adult (p<0.05) and 1.2 fewer nymphal ticks (p=0.01) at feeder sites. This effect intensified over time with one fewer tick trapped at old feeders (≥5 years) compared to new feeders (<5 years, p<0.05). Greater daily wildlife visitation rates (p<0.001) may have allowed questing ticks to encounter hosts more readily. Most collected ticks were
(92.8%), a vector of
and
pathogens, though prevalence of these pathogens did not differ (p>0.13) at a local scale. Supplemental deer feeding appears to influence ticks, possibly due to decreased tick habitat and increased wildlife use around feeders. Our findings indicate feeding does not lead to increased prevalence of
or
bacteria within
locally.
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•Ungulate-adapted forestry increases food availability via felling and scarification.•Undamaged Scots pine (Pinus sylvestris) increased near ungulate-adapted slash piles.•Undamaged ...Scots pine increased near stands with intensive scarification.•Effects of ungulate-adapted forestry were greatest at smallest spatial scales.
High densities of ungulates can increase human-wildlife conflicts. Where forestry is an important economy, intensive browsing can lead to browsing damage, resulting in volume losses, poor stand regeneration, and reduced timber quality. The forestry industry thus looks for practical, long-term measures to mitigate browsing damage. We tested the effect of two mitigation measures on moose (Alces alces) browsing behaviour and damage to Scots pine (Pinus sylvetris): (1) ungulate-adapted slash piles (i.e., palatable species only) created during felling to increase short-term food availability and (2) intensified soil scarification to increase long-term food availability (collectively, ‘ungulate-adapted forestry’). Our study occurred in southern Norway where we established fixed vegetation and moose faecal pellet plots at varying distances from conventional and ungulate-adapted slash piles and scarified stands. We evaluated the effects of ungulate-adapted slash piles and intensified scarification on the density of undamaged Scots pine, moose bite diameters, browsing pressure, and moose faecal pellet density. To assess the effect of spatial scale, we created 250 m, 500 m, and 1000-m radius buffers centered on each plot. We found that ungulate-adapted logging near our plots increased the density of undamaged pines, as compared to no and conventional logging. We found that logging in general led to smaller bite diameters. We also found that plots near conventional logging had higher browsing pressure, whereas browsing pressure near ungulate-adapted logging was similar to unlogged stands. For scarification, density of undamaged pine increased when the ungulate-adapted stand aged whereas undamaged pine decreased as conventional scarification stands aged. Browsing pressure showed a response at the smallest spatial scale only for ungulate-adapted scarification. Peak moose habitat use near conventional and ungulate-adapted scarified stands differed by stand age and distance from scarification. The overall effects of ungulate-adapted forestry were most pronounced at the smallest spatial scale (250 m). Our results support ‘ungulate-adapted’ forestry as a practical solution to mitigate browsing damage but uncertainty in some of our estimates suggest further research on the area treated is needed.
There is growing recognition that variation in animal personality traits can influence survival and reproduction rates, and consequently may be important for wildlife population dynamics. Despite ...this, the integration of personality research into conservation has remained uncommon. Alongside the establishment of personality as an important source of individual variation has come an increasing interest in factors affecting the development of personality. Recent work indicates the early environment, including natal nutrition, may play a stronger role in the development of personality than previously thought. In this study, we investigated the importance of three personality metrics (activity, boldness and acclimation time) for estimating survival of a threatened species, the hihi (Notiomystis cincta), and evaluated the influence of early natal nutrition on those metrics. Our results showed that boldness (as measured from a one-off cage test) had a positive effect on the probability of juvenile hihi surviving to adulthood. There was also a tendency for juveniles that received carotenoid supplementation in the nest to be bolder than those that did not, suggesting that the early environment had some influence on the expression of boldness in juvenile hihi. Linking the development of personality traits with ultimate effects on vital rates may benefit conservation management, as it could enable developmentally targeted management interventions. To our knowledge, this study is the first to identify potential linkages between early natal nutrition, personality and fitness in a wild-living population. This article is part of the theme issue 'Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.
Wild boar Sus scrofa is increasing in numbers and extending its distribution across Europe and is difficult to control due to high reproductive potential. Dietary quality is a main determinant of ...wild boar population dynamics, and the extent to which they rely on human‐provided food provide a key to limit their distribution. Yet, we lack data on wild boar diet from northern Europe. Here we use DNA‐metabarcoding of faecal samples (n = 50) to determine wild boar diet during fall and winter in Norway. We mainly aimed to quantify the extent to which wild boar relies on natural or human‐provided food sources. A secondary aim was to determine whether diet varies with individual characteristics (sex, age or weight), season (winter or fall), and between the two regions with wild boar in Norway. We found a high degree of diet variability between individuals. Individuals consuming high amounts of edible fungi consumed low amounts of plant material. The (heavier) male wild boars consumed 50% more human provided food than the (lighter) female wild boars. There was no clear effect of age, season (winter versus fall), or region on diet with the sample size available. The negative correlation between plants and fungi in each sample suggests that using multiple primers targeting different taxa can provide quantitative diet information, and points to an important role of fungi (truffles) during winter and fall. The large individual variation in diet may reflect opportunistic feeding tactics in Scandinavian boreal forests, driven by a lack of acorns and few crops. Our study has relevance for understanding limitations of wild boars at their northern distribution range in Europe, and thus also provides important information for management.
Migratory animals undergo seasonal and often spectacular movements and perform crucial ecosystem services. In response to anthropogenic changes, including food subsidies, some migratory animals are ...now migrating shorter distances or halting migration altogether and forming resident populations. Recent studies suggest that shifts in migratory behaviour can alter the risk of infection for wildlife. Although migration is commonly assumed to enhance pathogen spread, for many species, migration has the opposite effect of lowering infection risk, if animals escape from habitats where pathogen stages have accumulated or if strenuous journeys cull infected hosts. Here, we summarize responses of migratory species to supplemental feeding and review modelling and empirical work that provides support for mechanisms through which resource-induced changes in migration can alter pathogen transmission. In particular, we focus on the well-studied example of monarch butterflies and their protozoan parasites in North America. We also identify areas for future research, including combining new technologies for tracking animal movements with pathogen surveillance and exploring potential evolutionary responses of hosts and pathogens to changing movement patterns. Given that many migratory animals harbour pathogens of conservation concern and zoonotic potential, studies that document ongoing shifts in migratory behaviour and infection risk are vitally needed.
This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.
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