Food Subsidy Effects on Host Foraging Behavior Shape Host-Macroparasite Infection Dynamics

This paper systematically analyzes the effect of agricultural input subsidies in developing countries on yield and income, using a meta-analysis. From three databases, the analysis identifies 12 studies with 32 estimated effects on yield and 23 estimated effects on income. The findings show that programs that provide subsidized fertilizer and improved seeds are associated with average increases of 18 percent in yields and 16 percent in farming household incomes. These findings suggest that agricultural subsidies can lead to increased yields and contribute to improved living standards.

Agricultural subsidies have an important effect on the farmer’s fertilizer application behavior, but the differences in the effect on different farmers and its mediating mechanism have not been sufficiently studied. Using relevant data from the CFHS database in 2015, this paper focused on the differences in the effect of agricultural subsidies on fertilizer application intensity among farmers with different operation scales and planting structures, as well as the mediating mechanism of the effect of agricultural subsidies on farmers’ fertilizer application intensity. It was found that agricultural subsidies in general helped farmers reduce fertilizer application. This finding still held after replacing the explanatory variables. However, the effect of agricultural subsidies on fertilizer application intensity varied significantly across farmers with different operation scales and planting structures. The fertilizer reduction effect of agricultural subsidies was weakened by the increase in the operation scale and the share of food crop cultivation, i.e., the fertilizer reduction effect of agricultural subsidies on smaller farmers and cash crop cultivation was greater relative to larger farmers and food crop cultivation. Farmers’ operation scale, planting structure and farm machinery inputs are important mediating variables of the effect of agricultural subsidies on farmers’ fertilizer application intensity. The agricultural subsidies played a role in reducing fertilizer application intensity by encouraging farmers to expand their operation scale and increase food crop cultivation, and increased fertilizer application intensity by incentivizing farmers to purchase farm machinery and adopt mechanical farming. Finally, some suggestions were put forward to play the fertilizer reduction effect of agricultural subsidies based on the findings of the study.

A Net-back Analysis of Irrigation Water Demand in East Anglia

Fiscal and land policies are important tools in developing agriculture in China. Understanding how agricultural subsidies and land fragmentation jointly affect agricultural Total Factor Productivity (TFP) is crucial for building a strong agricultural nation. This paper utilizes microdata from fixed observation points in rural China from 2003 to 2017 and employs panel bidirectional fixed-effect models and moderation-effect models to empirically analyze the impact of agricultural subsidies and land fragmentation on agricultural TFP. The research finds: (1) Agricultural subsidies positively affect agricultural TFP, while land fragmentation leads to decreased agricultural TFP. (2) Land fragmentation hinders the positive effects of agricultural subsidies on agricultural TFP. A 1% increase in land fragmentation could lead to approximately a 3% decrease in the enhancement effect of agricultural subsidies, with significant impacts on households in major grain-producing areas and those primarily engaged in agriculture. (3) There is no evidence that reforms in the “three agricultural subsidies” would alter the combined effect of agricultural subsidies and land fragmentation on agricultural TFP. The obstructive role of land fragmentation cannot be mitigated through the “three agricultural subsidies” reform. The study indicates that the incentivizing role of agricultural subsidies has not been fully realized, and land fragmentation remains a key bottleneck in agricultural development. Fiscal support for agriculture should be coupled with effective land reform policies for synergistic efforts.

This article assesses the impact of the world price-depressing effect of agricultural subsidies and border protection in Organization for Economic Co-operation and Development (OECD) countries on developing economies' exports, imports, and welfare. Developing economy exporters are likely to benefit from reductions in such subsidies and trade barriers, whereas net importers may lose as world prices rise. A simple partial equilibrium model of global trade in commodities that benefit from domestic support or export subsidies is developed to estimate the relevant elasticities. Simulation results suggest that a 50 percent reduction in border protection will have a much larger positive impact on developing economies' exports and welfare than a 50 percent reduction in agricultural subsidies. Although there is significant heterogeneity across developing economies, the results suggest that efforts in the Doha round of World Trade Organization (WTO) negotiations should be directed at substantially reducing border protection.

The poleward range shift of the red fox (Vulpes vulpes)>1,700km into the Arctic is one of the most remarkable distribution changes of the early twentieth century. While this expansion threatens a smaller arctic ecological equivalent, the arctic fox (Vulpes lagopus), the case became a textbook example of climate-driven range shifts. We tested this classical climate change hypothesis linked to an important range shift which has attracted little research thus far. We analysed Canadian fur harvest data from the Hudson's Bay Company Archives (14 trading posts; 1926-1950), testing hypotheses based on changes in summer and winter climates. Summer warming might have triggered a bottom-up increase in ecosystem productivity, while winter warming might have lowered thermal stress, both favouring red fox expansion. Additionally, we evaluated the hypothesis that red fox expansion was driven by the appearance of human sedentary sites (n=110) likely bringing food subsidies into the unproductive tundra. Analysis of red fox expansion chronologies showed that expansion speed was higher during warmer winters. However, the expansions occurred under both cooling and warming trends, being faster during cooler summers in the Baffin Island region. The increasing proportion of red fox in fox fur harvests was best explained by human activity, while generalized linear mixed models also revealed a marginal effect of warmer winters. Generalized additive models confirmed human presence as the most important factor explaining rates of change in the proportion of red fox in fox fur harvests. Using historical ecology, we disentangled the relative influences of climate change and anthropogenic habitat change, two global drivers that transformed arctic biodiversity during the last century and will likely continue to do so during this century. Anthropogenic food subsidies, which constitute stable food sources, facilitated the invasion of the tundra biome by a new mammalian predator and competitor, with long-term consequences that still remain to be understood.

Anthropogenic food subsidies hinder the ecological role of wolves: Insights for conservation of apex predators in human-modified landscapes

Predicting how elevated temperatures from climate change alter host-parasite interactions requires understandings of how warming affects host susceptibility and parasite virulence. Here, the effect of elevated water temperature and parasite exposure level was tested on parasite prevalence, abundance and burden, and on fish growth, using Pomphorhynchus laevis and its fish host Squalius cephalus. At 60 days post-exposure, prevalence was higher at the elevated temperature (22 °C) than ambient temperature (18 °C), with infections achieved at considerably lower levels of exposure. Whilst parasite number was significantly higher in infected fish at 22 °C, both mean parasite weight and parasite burden was significantly higher at 18 °C. There were, however, no significant relationships between fish growth rate and temperature, parasite exposure, and the infection parameters. Thus, whilst elevated temperature significantly influenced parasite infection rates, it also impacted parasite development rates, suggesting warming could have complex implications for parasite dynamics and host resistance.

Ants play a central role in seed dispersal and predation, shaping plant recruitment, yet their foraging behavior is increasingly influenced by anthropogenic food subsidies. In human-modified landscapes, processed food waste may disrupt ant-seed interactions by diverting foragers or altering activity patterns, but the extent and mechanisms of these effects across habitats remain unclear. We conducted three field experiments in Panama to test how common food residues affect seed removal by ants in urban and forest environments. Using oat seeds as standardized diaspores, we (1) tested whether potato chips surrounding seed depots reduced removal, (2) evaluated the effects of adjacent chips or cookies on removal rates, ant activity, and species composition, and (3) manipulated the distance between chips and seeds (0, 30, 60 cm) to distinguish behavioral distraction from physical obstruction. Across experiments, seeds near food residues were removed significantly more slowly than controls, approximately half as fast in both habitats, despite differences in ant assemblages. Ant activity near seeds declined in the presence of food, particularly in the urban site. Suppression of seed removal occurred at close range but disappeared at 60 cm. These findings indicate that food waste disrupts ant-mediated seed removal through fine-scale behavioral shifts across contrasting habitats.

Parental care often produces a trade-off between meeting nutritional demands of offspring and the duties of offspring protection, especially in altricial species. Parents have to leave their young unattended for foraging trips, during which nestlings are exposed to predators. We investigated how rodent mothers of altricial young respond to risk of nest predation in their foraging decisions. We studied foraging behavior of lactating bank voles (Myodes glareolus) exposed to a nest predator, the common shrew (Sorex araneus). We conducted the experiment in summer (high resource provisioning for both species) and autumn (less food available) in 12 replicates with fully crossed factors “shrew presence” and “season.” We monitored use of feeding stations near and far from the nest as measurement of foraging activity and strategic foraging behavior. Vole mothers adapted their strategies to shrew presence and optimized their foraging behavior according to seasonal constraints, resulting in an interaction of treatment and season. In summer, shrew presence reduced food intake from feeding stations, while it enhanced intake in autumn. Shrew presence decreased the number of visited feeding stations in autumn and concentrated mother’s foraging efforts to fewer stations. Independent of shrew presence or season, mothers foraged more in patches further away from the nest than near the nest. Results indicate that females are not investing in nest guarding but try to avoid the accumulation of olfactory cues near the nest leading a predator to the young. Additionally, our study shows how foraging strategies and nest attendance are influenced by seasonal food provision.

Gulls are opportunistic birds that take advantage of anthropogenic food subsidies, often leading to conflicts with human populations. In Argentina, the Kelp Gull ( Larus dominicanus ) is distributed along the Atlantic coast and in some freshwater environments. We evaluated the trophic ecology of a population nesting in Nahuel Huapi Lake, with access to anthropogenic food subsidies. We used complementary methodologies (pellets, stomach contents, stable isotopes) to determine their diet during the incubation and chick‐rearing periods in 2019 and 2020, in two colonies (~261 and 314 nests) located close to urban areas. Pellets showed a relatively high percentage of anthropogenic food resources (>40%) and terrestrial arthropod remains (>40%) in all breeding stages and years, except during incubation in 2019, when >70% of rodent remains were recorded. Stomach contents also showed a high percentage of garbage in both years (40–80% incubating adults, 30–40% chicks) and of terrestrial arthropods (30–60%). Isotopic niche width differed between years, and the isotopic composition ( δ 13 C and δ 15 N) of adult and chick red blood cells showed a significant proportion of terrestrial resource (natural and anthropogenic items combined) consumption in all stages and years and a lower proportion of garbage in 2019. This study shows the generalist and opportunistic habits of Kelp Gulls at the Nahuel Huapi Lake colonies, evidenced by the wide variety of food consumed and the ability to take advantage of the food that becomes available in the natural environment (e.g., rodent outbreak throughout 2019). This study of the trophic ecology of the Kelp Gulls in the Nahuel Huapi Lake provides essential baseline information for future assessments of the gulls' demographic behaviour and their role within the urban‐lake‐terrestrial ecosystem. Further studies to understand the use of resources during the non‐breeding season are recommended.

Synchrony can have important consequences for long-term metapopulations persistence, community dynamics and ecosystems functioning. While the causes and consequences of intra-specific synchrony on population size and demographic rates have received considerable attention only a few factors that may affect inter-specific synchrony have been described. We formulate the hypothesis that food subsidies can buffer the influence of environmental stochasticity on community dynamics, disrupting and masking originally synchronized systems. To illustrate this hypothesis, we assessed the consequences of European policies implementation affecting subsidy availability on the temporal synchrony of egg volume as a proxy of breeding investment in two sympatric marine top predators with differential subsidy use. We show how 7-year synchrony appears on egg volume fluctuations after subsidy cessation suggesting that food subsidies could disrupt interspecific synchrony. Moreover, cross correlation increased after subsidy cessation and environmental buffering seems to act during synchronization period. We emphasize that subsidies dynamics and waste management provide novel insights on the emergence of synchrony in natural populations.

This paper examines the economic impact of agricultural subsidies on both farmers and markets. Agricultural subsidies, designed to support farm income and stabilize food prices, have far-reaching implications for agricultural production, market dynamics, and farmer welfare. This study utilizes a comprehensive review of existing literature, economic models, and empirical data to assess how subsidies influence agricultural output, market prices, and the distribution of economic benefits among farmers. The analysis reveals that while subsidies can provide immediate financial relief to farmers, they may also distort market mechanisms, lead to inefficiencies, and have unintended consequences on both local and global scales. This paper provides policy recommendations aimed at enhancing the effectiveness of agricultural subsidies and mitigating potential adverse effects.

The Political Effects of Agricultural Subsidies in Africa: Evidence from Malawi

Impacts of agricultural incentive policies on land rental prices: New evidence from China