Human activities create novel food resources that can alter wildlife–pathogen interactions. If resources amplify or dampen, pathogen transmission probably depends on both host ecology and pathogen ...biology, but studies that measure responses to provisioning across both scales are rare. We tested these relationships with a 4-year study of 369 common vampire bats across 10 sites in Peru and Belize that differ in the abundance of livestock, an important anthropogenic food source. We quantified innate and adaptive immunity from bats and assessed infection with two common bacteria. We predicted that abundant livestock could reduce starvation and foraging effort, allowing for greater investments in immunity. Bats from high-livestock sites had higher microbicidal activity and proportions of neutrophils but lower immunoglobulin G and proportions of lymphocytes, suggesting more investment in innate relative to adaptive immunity and either greater chronic stress or pathogen exposure. This relationship was most pronounced in reproductive bats, which were also more common in high-livestock sites, suggesting feedbacks between demographic correlates of provisioning and immunity. Infection with both Bartonella and haemoplasmas were correlated with similar immune profiles, and both pathogens tended to be less prevalent in high-livestock sites, although effects were weaker for haemoplasmas. These differing responses to provisioning might therefore reflect distinct transmission processes. Predicting how provisioning alters host–pathogen interactions requires considering how both within-host processes and transmission modes respond to resource shifts.
This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.
Conservation of migration requires information on behavior and environmental determinants. The spatial distribution of forage resources, which migration exploits, often are altered and may have ...subtle, unintended consequences. Supplemental feeding is a common management practice, particularly for ungulates in North America and Europe, and carryover effects on behavior of this anthropogenic manipulation of forage are expected in theory, but have received limited empirical evaluation, particularly regarding effects on migration. We used global positioning system (GPS) data to evaluate the influence of winter feeding on migration behavior of 219 adult female elk (
Cervus elaphus
) from 18 fed ranges and 4 unfed ranges in western Wyoming. Principal component analysis revealed that the migratory behavior of fed and unfed elk differed in distance migrated, and the timing of arrival to, duration on, and departure from summer range. Fed elk migrated 19.2 km less, spent 11 more days on stopover sites, arrived to summer range 5 days later, resided on summer range 26 fewer days, and departed in the autumn 10 days earlier than unfed elk. Time-to-event models indicated that differences in migratory behavior between fed and unfed elk were caused by altered sensitivity to the environmental drivers of migration. In spring, unfed elk migrated following plant green-up closely, whereas fed elk departed the feedground but lingered on transitional range, thereby delaying their arrival to summer range. In autumn, fed elk were more responsive to low temperatures and precipitation events, causing earlier departure from summer range than unfed elk. Overall, supplemental feeding disconnected migration by fed elk from spring green-up and decreased time spent on summer range, thereby reducing access to quality forage. Our findings suggest that ungulate migration can be substantially altered by changes to the spatial distribution of resources, including those of anthropogenic origin, and that management practices applied in one season may have unintended behavioral consequences in subsequent seasons.
Aquaculture in Central Europe is mainly performed in man-made fishponds. Common carp (Cyprinus carpio), the main fish species, grows on natural food developing in fishponds and supplemental feeds ...(SF). Previously, it was found that common carp (CC) growth may be improved by selective breeding (SB). However, there is a question if such stocks could utilize the fishpond natural resources better and increase the mass yield per unit of water surface area. Otherwise, SB would be useless. In this study, we compared the production parameters of two mirror CC stocks (M2 and M2 x AMC) fed with two supplemental feeds (grain and carp plant-based pellets). The cross-bred M2 x AMC represented a model stock with higher performance potential comparable to a stock after several generations of SB for better growth. The study was performed in fishponds of Fish Farm Klatovy under their common practice over the three age categories of carp (CO – C3). Each mirror carp stock was reared separately with an internal scaly control group (CG) to evaluate potential environmental biases. Performance and production parameters between the two mirror carp groups and distributed SF were compared from a total of 43 fishponds using generalized linear models. It was found that the M2 x AMC showed remarkably higher overall mean individual weight gain (by 24.9%; 281 g vs. 351 g) and survival (by 16%; 46.6% vs. 54.4%). Moreover, fishponds stocked with the M2 x AMC displayed significantly higher (23.7 – 58.3%) mirror and total carp mass and mirror, total, standardized, relative and estimated carp mass yields, while the CG performed similarly in both groups of fishponds. No effects of the SFs on the production parameters were observed. Results suggest that SB for faster growth in common carp for a minimum of 3–5 generations should be manifested in a gradual increase of mass yields without changing the fishpond management.
•The group with higher performance potential showed remarkably higher overall mean individual weight gain and survival.•The group with higher performance potential achieved significantly higher mirror and total carp mass and mass yields.•No effect of the two supplemental feeds tested on the fishpond production parameters was observed.•Selective breeding for faster growth for minimum of 3–5 generations should be manifested in a gradual. increase of mass yields.
The influence of various diets on the quality of Apis mellifera queens was assessed. Colonies intended for queen cell production were assigned to four groups fed on (1) sugar-only, (2) mix of sugar, ...honey and fresh pollen, (3) sugar and pollen substitute (FeedBee®), and (4) natural sources. In addition, a fifth group had queen cells obtained naturally, by swarming. Sugar-only diet exerted a significant (p < 0.05) stimulating effect on the acceptance of queen cells and the weight of newly emerged queens, not affecting mated queens. Among mated queens those raised by bees fed on the mix of sugar, honey and fresh pollen had significantly (p < 0.05) larger numbers of ovarioles in comparison with all the others. Their weight was significantly higher than that of the queens from groups given FeedBee
®
and swarming queens. Compared to the latter, they had significantly wider spermatheca. Given the parameters monitored, FeedBee
®
proved not to be advantageous for queens.
Human behavior profoundly affects the natural world. Migratory birds are particularly susceptible to adverse effects of human activities because the global networks of ecosystems on which birds rely ...are undergoing rapid change. In spite of these challenges, the blackcap (Sylvia atricapilla) is a thriving migratory species. Its recent establishment of high‐latitude wintering areas in Britain and Ireland has been linked to climate change and backyard bird feeding, exemplifying the interaction between human activity and migrant ecology. To understand how anthropogenic influences shape avian movements and ecology, we marked 623 wintering blackcaps at 59 sites across Britain and Ireland and compiled a dataset of 9929 encounters. We investigated visitation behavior at garden feeding sites, inter‐annual site fidelity, and movements within and across seasons. We analyzed migration tracks from 25 geolocators fitted to a subset of individuals to understand how garden behavior may impact subsequent migration and breeding. We found that blackcaps wintering in Britain and Ireland showed high site fidelity and low transience among wintering sites, in contrast to the itinerant movements characteristic of blackcaps wintering in their traditional winter range. First‐winter birds showed lower site fidelity and a greater likelihood of transience than adults. Adults that frequented gardens had better body condition, smaller fat stores, longer bills, and rounder wingtips. However, blackcaps did not exclusively feed in gardens; visits were linked to harsher weather. Individuals generally stayed at garden sites until immediately before spring departure. Our results suggest that supplementary feeding is modifying blackcap winter ecology and driving morphological evolution. Supplemental feeding may have multifaceted benefits on winter survival, and these positive effects may carry over to migration and subsequent breeding. Overall, the high individual variability in blackcap movement and foraging ecology, and the flexibility it imparts, may have allowed this species to flourish during rapid environmental change.
Human behavior profoundly affects the natural world, and migratory birds are particularly susceptible. Recent changes in blackcap (Sylvia atricapilla) migration are linked to a warming climate and garden bird feeding. Using tracking data and visual observations, we found that blackcaps wintering in Britain and Ireland use gardens most frequently during harsher weather and are less mobile than individuals in their traditional Mediterranean winter range. Adults that favored gardens had better body condition and morphological traits linked to supplementary feeding and residency. We show that multiple anthropogenic forces are shaping blackcap biology, with implications for understanding responses to global change.
This study assessed potential improvement of sandfish (Holothuria scabra) culture using supplemental feeding with seaweed to explore its potential to support short-cropping. Three phased experiments ...evaluated juvenile growth and survival performance by: offering two types of seaweed-based supplemental feeds (Sargassum sp. and Gracilaria verrucosa) both processed by fermentation and pulverisation (Experiment 1); evaluating three stocking densities (25, 35 and 45 individuals per m2) using the best-performing diet from Experiment 1 (Experiment 2); and upscaling to commercial-level culture in three 400 m2 earthen ponds (Experiment 3). Fermented diets were prepared using a probiotic mixture (Saccharomyces boulardii, Lactobacillus acidophilus and Bacillus subtilis) added to ground, dried seaweed; while the pulverised diets were offered as a ground powder (350–450 µm particle sizes). Sandfish offered fermented Sargassum and Gracilaria reached 35.0% and 29.7% heavier mean final weights (18.18 ± 0.19 g and 16.81 ± 0.08 g, respectively), compared to their pulverised equivalents (11.82 ± 1.09 g across both seaweed species, p < 0.05) after 84 days of culture. Similar trends in growth rate (AGR and SGR) were evident. Fermented Sargassum sp. was therefore selected for subsequent experiments. During Experiment 2 the lowest density tested of 25 ind./m2 yielded the highest weight gain after 84 days, with juveniles 29.2% and 44.0% heavier respectively (final weight=18.20 ± 1.31 g), cf. 35 and 45 ind./m2, respectively (final weights=12.90 ± 0.71 and 10.20 ± 0.70 g, respectively). Growth at 25 ind./m2 was 15.7% faster (SGR=2.61 ± 0.09 g/day) compared to 35 ind./m2 (SGR=2.20 ± 0.07 g/day), and 26.5% faster relative to 45 ind./m2 (SGR=1.92±0.10 g/day). Sandfish grown in earthen ponds during Experiment 3 attained a final mean weight of 241.21 ± 0.84 g after 180 days. Final mean weights, weight gained and SGR (1.76 ± 0.06%/day) were not significantly different between ponds (p > 0.05). Valuable new information has been generated for further development of supplemental feeding of sandfish, and results here demonstrate high technical feasibility to support short cropping, with optimisation of this culture model required.
•Supplemental feeding of sandfish with seaweed is technically feasible.•Fermented Sargassum promoted fastest growth and heavier weights at harvest.•High utility for short cropping culture model in Vietnam using supplemental feed.•Increased system productivity and profitability benefits with supplemental feeding.
While urbanization is clearly contributing to biodiversity loss, certain wildlife assemblages can paradoxically be diverse and abundant in moderately developed areas. One hypothesis to explain this ...phenomenon is that abundant anthropogenic resources for wildlife (i.e., food and shelter) outweigh the costs associated with urbanization. To test this hypothesis, we used camera traps to measure mammal species richness, diversity, and relative abundance (i.e., detection rate) in 58 residential yards in Raleigh, North Carolina, focusing on six types of features that might be used as resources: animal feeding, vegetable gardens, compost piles, chicken coops, brushpiles, and water sources. We also placed cameras at random control sites within each yard and sampled forests in nearby suburban and rural areas for comparison. We fit mixed-effects Poisson models to determine whether yard features, yard-scale characteristics, or landscape-scale landcover predicted mammal relative abundance for eight species. We also tested if the relative abundance of native canid predators in yards was related to the number of prey (rodents and lagomorphs). Species richness, diversity, and relative abundance of most mammal species was higher in yards and suburban forests than in rural forests. Within a yard, purposeful feeding had the strongest effect on animal relative abundance, with eastern gray squirrels (Sciurus carolinensis) being the most common (32.3 squirrels/day at feeders; 0.55 at control sites; 0.29 in suburban forests; and 0.10 in rural forests). We observed species using (e.g., eating) most yard features, although canids were less likely than other taxa to use resources in yards. The presence of a yard feature did not strongly affect the abundance of species at the control site in the yard, suggesting the influence of these features was highly localized. The relative abundance of predators had a positive association with prey relative abundance, and predators were less common in yards with fences. These results demonstrate that there is high use of anthropogenic resources, especially supplemental feeding by urban wildlife, and this increase in prey species may then attract predators, which supports the hypothesis that use of supplemental food resources explains the abundance of urban wildlife.
Studying how animals interact with their environment is fundamental to informing conservation and management efforts, especially when examining large, wide-ranging carnivores in human-dominated ...landscapes. We hypothesized that the home ranges of bears are configured to exploit supplemental food (corn) and avoid people. In 2004–2016, we tracked 10 brown bears from the Dinaric-Pindos population using GPS telemetry, then used Brownian bridge movement models to estimate their home ranges. We related seasonal home range size to circadian period and density of supplemental feeding sites using generalized linear mixed-effect models. We also used ecological-niche factor analysis to study habitat composition within home range core areas in study areas characterized by different levels of human encroachment. We found that home range size was inversely related to density of supplemental feeding sites, and bears had larger home ranges at night (x̄ = 103.3 ± 72.8 km2) than during the day (x̄ = 62.3 ± 16.6 km2). Our results also revealed that bears living in more human-influenced areas concentrated their use far from human settlements and agricultural lands but stayed close to supplemental feeding sites. Our data suggest that bears alter their space-use patterns at the home range level in response to anthropogenic land use and food availability.
1. Supplemental food provided to wildlife by human activities can be more abundant and predictable than natural resources, and subsequent changes in wildlife ecology can have profound impacts on ...host-parasite interactions. Identifying traits of species associated with increases or decreases in infection outcomes with resource provisioning could improve assessments of wildlife most prone to disease risks in changing environments. 2. We conducted a phylogenetic meta-analysis of 342 host-parasite interactions across 56 wildlife species and three broad taxonomic groups of parasites to identify host-level traits that influence whether provisioning is associated with increases or decreases in infection. 3. We predicted dietary generalists that capitalize on novel food would show greater infection in provisioned habitats owing to population growth and food-borne exposure to contaminants and parasite infectious stages. Similarly, species with fast life histories could experience stronger demographic and immunological benefits from provisioning that affect parasite transmission. We also predicted that wide-ranging and migratory behaviours could increase infection risks with provisioning if concentrated and non-seasonal foods promote dense aggregations that increase exposure to parasites. 4. We found that provisioning increased infection with bacteria, viruses, fungi and protozoa (i.e. microparasites) most for wide-ranging, dietary generalist host species. Effect sizes for ectoparasites were also highest for host species with large home ranges but were instead lowest for dietary generalists. In contrast, the type of provisioning was a stronger correlate of infection outcomes for helminths than host species traits. 5. Our analysis highlights host traits related to movement and feeding behaviour as important determinants of whether species experience greater infection with supplemental feeding. These results could help prioritize monitoring wildlife with particular trait profiles in anthropogenic habitats to reduce infectious disease risks in provisioned populations.
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