Explore the vast range of titles available.

Plant isotopic baselines are critical for accurately reconstructing ancient diets and environments and for using stable isotopes to monitor ecosystem conservation. This study examines the stable carbon and nitrogen isotope compositions (δ13C, δ15N) of terrestrial C3 plants in Elk Island National Park (EINP), Alberta, Canada, with a focus on plants consumed by grazers. EINP is located in a boreal mixed woodland ecozone close to the transition area between historic wood and plains bison habitats, and is currently home to separate herds of wood and plains bison. For this study, 165 C3 plant samples (grasses, sedges, forbs, shrubs, and horsetail) were collected from three habitat types (open, closed, and wet) during two seasons (summer and fall). There were no statistically significant differences in the δ13C or δ15N values of grasses, sedges, shrubs and forbs. On the other hand, plant δ13C and δ15N values varied among habitats and plant parts, and the values increased from summer to fall. These results have several implications for interpreting herbivore tissue isotopic compositions: (1) consuming different proportions of grasses, sedges, shrubs, and forbs might not result in isotopic niche partitioning, (2) feeding in different microhabitats or selecting different parts of the same types of plants could result in isotopic niche partitioning, and (3) seasonal isotopic changes in herbivore tissues could reflect seasonal isotopic changes in dietary plants rather than (or in addition to) changes in animal diet or physiology. In addition, the positively skewed plant δ15N distributions highlight the need for researchers to carefully evaluate the characteristics of their distributions prior to reporting data (e.g., means, standard deviations) or applying statistical models (e.g., parametric tests that assume normality). Overall, this study reiterates the importance of accessing ecosystem-specific isotopic baselines for addressing research questions in archaeology, paleontology, and ecology.

In-home and shared meals have been hypothesized to have positive effects. This narrative review examines research on the influence of in-home eating on diet quality, health outcomes, and family relationships. A combination search approach included a search of PubMed, backward searches of previous published reviews, and studies the authors were familiar with. A search identified 118 publications; 54 original studies and 11 review studies were included in this review. Each study was reviewed and summarized. The diverse designs precluded quantitative data synthesis. Relatively strong evidence from cross-sectional research supports the association of shared family meals with favorable dietary patterns in children and adolescents, including consumption of fruits, vegetables, and healthful nutrients. Correlational evidence links shared meals with health and psychosocial outcomes in youth, including less obesity, decreased risk for eating disorders, and academic achievement. Most evidence is cross-sectional, thus, limiting attribution of causality. There is insufficient evidence to conclude that interventions improve the frequency of shared meals, improve diet, or prevent child obesity. Despite the “common wisdom”, the evidence that in-home, shared meals, per se, have positive effects on diet quality, health outcomes, psychosocial outcomes, and family relationships is limited due to weak research designs and single-item measurement of the independent variable. More research, with stronger designs, is warranted.

Understanding woolly mammoth ecology is key to understanding Pleistocene community dynamics and evaluating the roles of human hunting and climate change in late Quaternary megafaunal extinctions. Previous isotopic studies of mammoths’ diet and physiology have been hampered by the ‘mammoth conundrum’: woolly mammoths have anomalously high collagen δ 15 N values, which are more similar to coeval carnivores than herbivores and which could imply a distinct diet and (or) habitat, or a physiological adaptation. We analyzed individual amino acids from collagen of adult woolly mammoths and coeval species and discovered greater   15 N enrichment in source amino acids of woolly mammoths than in most other herbivores or carnivores. Woolly mammoths consumed an isotopically distinct food source, reflective of extreme aridity, dung fertilization and (or) plant selection. This dietary signal suggests that woolly mammoths occupied a distinct habitat or forage niche relative to other Pleistocene herbivores.

Background School meal programs have a large reach and thus are ideal environments in which to implement interventions targeting improved youth eating behaviors and reduced food waste. This systematic review summarizes the evidence on the effectiveness of school meal nudge interventions on influencing children’s eating and waste behaviors. Methods Inclusion criteria required studies have participants in primary or secondary school (grades K-12) with interventions that occurred during school lunch or breakfast in the cafeteria and included at least one of the following outcomes: selection, consumption, waste, or school meal participation. Analyses of intervention outcomes were restricted to studies of strong and moderate quality. Results Twenty-nine studies were included in the quality assessment. Included interventions fell into three categories: 1) placement/convenience, 2) marketing/promotion, or 3) variety/portions. The 20 strong and moderate quality studies included in outcome analyses generally used strong data collection methods and study designs, but were limited by an overall lack of intervention fidelity checks. Multi-component interventions often did not use methods that allowed for separate analyses of outcomes for different intervention components. Conclusions School meal nudge interventions were positively associated with food selection, and had an inconsistent relationship with food consumption. There were few studies evaluating the impact of nudge interventions on meal participation or food waste. The limited evidence available links nudges to improved meal participation, as well as undesirable increases in food waste. Future research in this area should use methods that incorporate implementation metrics, attend to systems factors, and allow the outcomes of individual intervention components to be isolated.

Emerging evidence suggests a link between young people’s interest in alternative food production practices and dietary quality. The primary purpose of this study was to examine the impact of a student-driven sustainable food systems education and promotion intervention on adolescent school lunch selection, consumption, and waste behaviors. Sixth grade science teachers at two middle schools (n = 268 students) implemented a standards-based curriculum on sustainable food systems, addressing the environmental impacts of food choices and food waste. The cumulating curriculum activity required the 6th grade students to share their food systems knowledge with their 7th and 8th grade counterparts (n = 426) through a cafeteria promotional campaign to discourage food waste. School-wide monthly plate waste assessments were used to evaluate changes in vegetable consumption and overall plate waste using a previously validated digital photography method. At baseline, the intervention students consumed significantly less vegetables relative to the control group (47.1% and 71.8% of vegetables selected, respectively (p = 0.006). This disparity was eliminated after the intervention with the intervention group consuming 69.4% and the control consuming 68.1% of selected vegetables (p = 0.848). At five months follow up, the intervention group wasted significantly less salad bar vegetables compared to the control group (24.2 g and 50.1 g respectively (p = 0.029). These findings suggest that food systems education can be used to promote improved dietary behaviors among adolescent youth.

The main objective of this study was to evaluate the impact of the Market to MyPlate (M2MP) program on fruit and vegetable consumption and cooking behaviours. Secondary objectives were to examine factors that affected participant retention and program completion, and analyse program feedback provided by participants. This study conducted a mixed methods evaluation embedded within a cluster randomised controlled trial of the M2MP intervention. Adult participants completed a pre- and post-program survey reporting on their fruit and vegetable consumption and cooking behaviours. A subsample participated in structured interviews, providing feedback about M2MP and the impact of the program. Seven weekly classes took place in community centres and extension offices in central Illinois. 120 adults and their families participated. Class cohorts were randomly assigned to one of three treatment groups: (1) nutrition education and cooking classes with produce allocations (PAE, n 39); (2) nutrition education and cooking classes only (EO, n 36) or (3) control group (n 45). Compared to control, PAE participants reported larger increases from pre- to post-intervention in fruit (P = 0·001) and vegetable consumption (P = 0·002), with no differences in cooking frequency. Interview analyses identified key themes in behaviour changes due to M2MP, including reported increases in dietary variety, cooking self-efficacy and children's participation in cooking. PAE participants who received an intervention that directly increased their access to fresh produce (via produce allocations) increased their reported fruit and vegetable consumption. Though participants' cooking frequency did not change, interviewees reported increased variety, cooking confidence and family participation in cooking.

The isotopic compositions of plants can provide significant insights into paleodiets, ancient agricultural activities, and past environments. Isotopic compositions of charred (aka carbonized) ancient plant remains are typically preferred over those of uncharred/ -uncarbonized plants, both because charred plants are more commonly preserved and because early research suggested they experience less post-depositional isotopic alteration. In this paper, we re-explore the question of whether uncharred plants experience large-magnitude post-depositional changes in carbon and nitrogen isotope compositions by analyzing Terminal Pleistocene–Early Holocene plant specimens from rockshelters in the Escalante River Basin (Colorado Plateau, southeastern Utah). Several lines of evidence, including C3-CAM differences, plant-part comparisons, and dietary estimates from ancient herbivore collagen, suggest that the original carbon isotope compositions of these plants have not been significantly altered. The preservation status of plant nitrogen isotope compositions is equivocal. The direction of temporal shifts in plant δ15N matches global trends and the magnitude of the shift may have been exacerbated by the extinction of megafauna in an arid environment. However, the Pleistocene plant δ15N values are higher than would be expected based on herbivore bone collagen δ15N. Nevertheless, in contrast to previous research, the ancient uncharred plants in this study did not have exceptionally high δ15N values (> + 25‰). Overall, our research suggests that uncharred plants could be useful substrates for isotopic paleodietary and/or paleoenvironmental studies.

The objective of the current study was to evaluate the impact of the Market to MyPlate (M2MP) program on participants' reported farmers' market (FM) attitudes and shopping behaviours, frequency of serving vegetables to their families, food resource management behaviours and food security. A secondary objective was to identify facilitators and barriers to shopping at FM and food waste reduction techniques used by low-income families. The current study used a mixed methods evaluation embedded within a cluster randomised trial of the M2MP intervention. The 7-week M2MP program was delivered at Extension offices and community centres in central Illinois. Participants included 120 adults and their families. Class cohorts were randomly assigned to one of three treatment groups: (1) nutrition education and cooking classes with produce allocations (PAE, 39); (2) nutrition education and cooking classes only (EO, 36) or (3) control group ( 45). Compared with control participants, PAE participants were significantly more likely to report shopping at FM ( = 0·029) and reported serving more vegetables to their families ( = 0·010) (EO participants did not differ from the control group on any outcomes). There were no differences between conditions in survey-based measures of food security or food resource management behaviours. Interview results describe facilitators and barriers to shopping at FM and a variety of food waste reduction techniques (including food placement and food resource management). These findings suggest that fresh produce provision coupled with nutrition and culinary education can positively impact shopping and dietary behaviours.

The Promontory caves (Utah) and Franktown Cave (Colorado) contain high-fidelity records of short-term occupations by groups with material culture connections to the Subarctic/Northern Plains. This research uses Promontory and Franktown bison dung, hair, hide, and bone collagen to establish local baseline carbon isotopic variability and identify leather from a distant source. The ankle wrap of one Promontory Cave 1 moccasin had a δ13C value that indicates a substantial C4 component to the animal's diet, unlike the C3 diets inferred from 171 other Promontory and northern Utah bison samples. We draw on a unique combination of multitissue isotopic analysis, carbon isoscapes, ancient DNA (species and sex identification), tissue turnover rates, archaeological contexts, and bison ecology to show that the high δ13C value was not likely a result of local plant consumption, bison mobility, or trade. Instead, the bison hide was likely acquired via long-distance travel to/from an area of abundant C4 grasses far to the south or east. Expansive landscape knowledge gained through long-distance associations would have allowed Promontory caves inhabitants to make well-informed decisions about directions and routes of movement for a territorial shift, which seems to have occurred in the late thirteenth century.

Significance New radiocarbon ( ¹⁴C) dates on American mastodon ( Mammut americanum ) fossils in Alaska and Yukon suggest this species suffered local extirpation before terminal Pleistocene climate changes or human colonization. Mastodons occupied high latitudes during the Last Interglacial (∼125,000–75,000 y ago) when forests were established. Ecological changes during the Wisconsinan glaciation (∼75,000 y ago) led to habitat loss and population collapse. Thereafter, mastodons were limited to areas south of the continental ice sheets, where they ultimately died out ∼10,000 ¹⁴C years B.P. Extirpation of mastodons and some other megafaunal species in high latitudes was thus independent of their later extinction south of the ice. Rigorous pretreatment was crucial to removing contamination from fossils that originally yielded erroneously “young” ¹⁴C dates. Existing radiocarbon ( ¹⁴C) dates on American mastodon ( Mammut americanum ) fossils from eastern Beringia (Alaska and Yukon) have been interpreted as evidence they inhabited the Arctic and Subarctic during Pleistocene full-glacial times (∼18,000 ¹⁴C years B.P.). However, this chronology is inconsistent with inferred habitat preferences of mastodons and correlative paleoecological evidence. To establish a last appearance date (LAD) for M. americanum regionally, we obtained 53 new ¹⁴C dates on 36 fossils, including specimens with previously published dates. Using collagen ultrafiltration and single amino acid (hydroxyproline) methods, these specimens consistently date to beyond or near the ∼50,000 y B.P. limit of ¹⁴C dating. Some erroneously “young” ¹⁴C dates are due to contamination by exogenous carbon from natural sources and conservation treatments used in museums. We suggest mastodons inhabited the high latitudes only during warm intervals, particularly the Last Interglacial [Marine Isotope Stage (MIS) 5] when boreal forests existed regionally. Our ¹⁴C dataset suggests that mastodons were extirpated from eastern Beringia during the MIS 4 glacial interval (∼75,000 y ago), following the ecological shift from boreal forest to steppe tundra. Mastodons thereafter became restricted to areas south of the continental ice sheets, where they suffered complete extinction ∼10,000 ¹⁴C years B.P. Mastodons were already absent from eastern Beringia several tens of millennia before the first humans crossed the Bering Isthmus or the onset of climate changes during the terminal Pleistocene. Local extirpations of mastodons and other megafaunal populations in eastern Beringia were asynchrononous and independent of their final extinction south of the continental ice sheets.