Trust me? Consumer trust in expert information on food product labels.

Food product labels can provide consumers with rich, specific, expert-certified product information. However, sources of label information differ. How do consumers then evaluate label trustworthiness of expert labels in comparison to other commonly used label types? We present results from a representative online survey (N = 10,000) of consumers in Japan, the USA, Germany, China and Thailand using professionally designed labels for four food types (milk, honey, oil, wine) and five different sources of food information (farmers, government/administration, producer associations, experts, and consumers). We tested label legibility through identification of the label information source and asked respondents to evaluate the trustworthiness of labels using a six-scale instrument ranging from overall label trust to purchase intent. Results show that label legibility varied between countries, with expert labels scoring lowest. Nevertheless, respondents correctly identifying all label information sources chose expert labels as the most or second-most trustworthy across all countries and food types, while consumer labels scored low. Demographic factors exhibited weak influence. Results suggest expert labels might play an important role as trusted sources of information in an increasingly complex global food system. Finally, we consider the implications of the study for a potential institutionalization of expert labels based on the Japanese context.

Isotopic evidence for oligotrophication of terrestrial ecosystems.

Human societies depend on an Earth system that operates within a constrained range of nutrient availability, yet the recent trajectory of terrestrial nitrogen (N) availability is uncertain. Examining patterns of foliar N concentrations and isotope ratios (δ15N) from more than 43,000 samples acquired over 37 years, here we show that foliar N concentration declined by 9% and foliar δ15N declined by 0.6-1.6‰. Examining patterns across different climate spaces, foliar δ15N declined across the entire range of mean annual temperature and mean annual precipitation tested. These results suggest declines in N supply relative to plant demand at the global scale. In all, there are now multiple lines of evidence of declining N availability in many unfertilized terrestrial ecosystems, including declines in δ15N of tree rings and leaves from herbarium samples over the past 75-150 years. These patterns are consistent with the proposed consequences of elevated atmospheric carbon dioxide and longer growing seasons. These declines will limit future terrestrial carbon uptake and increase nutritional stress for herbivores.

Spatial variations in larch needle and soil δ15N at a forest-grassland boundary in northern Mongolia.

The spatial patterns of plant and soil δ15N and associated processes in the N cycle were investigated at a forest-grassland boundary in northern Mongolia. Needles of Larix sibirica Ledeb. and soils collected from two study areas were analysed to calculate the differences in δ15N between needle and soil (Δδ15N). Δδ15N showed a clear variation, ranging from -8 ‰ in the forest to -2 ‰ in the grassland boundary, and corresponded to the accumulation of organic layer. In the forest, the separation of available N produced in the soil with 15N-depleted N uptake by larch and 15N-enriched N immobilization by microorganisms was proposed to cause large Δδ15N, whereas in the grassland boundary, small Δδ15N was explained by the transport of the most available N into larch. The divergence of available N between larch and microorganisms in the soil, and the accumulation of diverged N in the organic layer control the variation in Δδ15N.