Browsing by Author "Raubenheimer D"

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    Diet affordability: a key dimension in the assessment of sustainable food systems and healthy diets
    (Frontiers Media S.A., 2024-08-12) Chungchunlam SMS; Moughan PJ; Raubenheimer D
    A promulgated global shift toward a plant-based diet is largely in response to a perceived negative environmental impact of animal food production, but the nutritional adequacy and economic implications of plant-sourced sustainable healthy dietary patterns need to be considered. This paper reviews recent modeling studies using Linear Programming to determine the respective roles of animal- and plant-sourced foods in developing a least-cost diet in the United States and New Zealand. In both economies, least-cost diets were found to include animal-based foods, such as milk, eggs, fish, and seafood, to meet the energy and nutrient requirements of healthy adults at the lowest retail cost. To model a solely plant-based least-cost diet, the prevailing costs of all animal-sourced foods had to be increased by 1.1 to 11.5 times their original retail prices. This led to the inclusion of fortified plant-based foods, such as fortified soymilk, and a plant-based diet that was considerably (34–45%) more costly. The first-limiting essential nutrients were mostly the vitamins and minerals, with special focus on pantothenic acid, zinc, and vitamin B-12, when transitioning from an animal- and plant-containing least-cost diet to a plant-only based least-cost diet. Modeled least-cost diets based on contemporary food costs include animal-sourced foods, at least for developed high-income US and NZ food economies, and potentially for developing low- and middle-income countries, such as Indonesia. Modeling of least-cost diets that consist exclusively of plant-based foods is feasible, but at a higher daily diet cost, and these diets are often close to limiting for several key nutrients. Diet affordability, as a key dimension of sustainable healthy diets, and the respective economic roles of animal- and plant-sourced foods need to be considered.
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    Patterns, perceptions, and spatial distribution of human-elephant (Elephas maximus) incidents in Nepal
    (Wildlife Information Liaison Development Society, 2021-05-28) Koirala RK; Ji W; Timilsina YP; Raubenheimer D; Davidar P
    Nepal has an estimated population of 109 to 142 wild Asian Elephants Elephas maximus L.. We carried out a survey of humanelephant incidents (HEI) of conflict in the buffer zones of Chitwan National Park and Parsa National Park Nepal, using a structured questionnaire, focal interviews, and secondary data collection. Furthermore, data of HEI were also extracted from published literature in order to analyse spatial-temporal patterns of competition throughout Nepal. Elephant related incidents were higher in the pre-winter season and concentrated along the southern forest boundary; incidents decreased with increasing distance from the park/reserve. Crop damage by elephants occurred in pre-monsoon and winter seasons with the most impact on rice (the major crop). Bulls (single or in pairs) were involved in crop raids (44%), property damage (48%), and human casualties (8%); family herds were only recorded to have raided crops (39%) and damaged properties (36%). The average herd size recorded was 10 individuals, with a maximum group size of <22 elephants. Generally, incidents per elephant was high in western Nepal, whereas human and elephant casualties were higher in central and eastern regions. To reduce human-elephant incidents 53% of local residents suggested restoring core and boundary areas with native elephant food plants, 40% suggested planting alternative crops along park boundaries, 6% favoured elephant translocation, and only 1% percent was in favour of culling elephants. Mitigation measures already in place include wooden watch towers used by villagers to detect elephant incursions. Low impact traditional averting techniques, such as drumming and the use of flame torches, were used to deter intruding elephants at the areas surveyed. In conclusion we suggest potential mitigation measures such as identifying elephant refugia and mitigate the impact and assessing the year-round availability of preferred foods; in addition, we advocate for introducing an equitable compensation to gain support from local communities adjacent to protected areas.
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    Tolerance for nutrient imbalance in an intermittently feeding herbivorous cricket, the Wellington tree weta.
    (PUBLIC LIBRARY SCIENCE, 2013) Wehi PM; Raubenheimer D; Morgan-Richards M
    Organisms that regulate nutrient intake have an advantage over those that do not, given that the nutrient composition of any one resource rarely matches optimal nutrient requirements. We used nutritional geometry to model protein and carbohydrate intake and identify an intake target for a sexually dimorphic species, the Wellington tree weta (Hemideina crassidens). Despite pronounced sexual dimorphism in this large generalist herbivorous insect, intake targets did not differ by sex. In a series of laboratory experiments, we then investigated whether tree weta demonstrate compensatory responses for enforced periods of imbalanced nutrient intake. Weta pre-fed high or low carbohydrate: protein diets showed large variation in compensatory nutrient intake over short (<48 h) time periods when provided with a choice. Individuals did not strongly defend nutrient targets, although there was some evidence for weak regulation. Many weta tended to select high and low protein foods in a ratio similar to their previously identified nutrient optimum. These results suggest that weta have a wide tolerance to nutritional imbalance, and that the time scale of weta nutrient balancing could lie outside of the short time span tested here. A wide tolerance to imbalance is consistent with the intermittent feeding displayed in the wild by weta and may be important in understanding weta foraging patterns in New Zealand forests.