Special issue: Questioning the roles of resources nutritional quality in ecology

Abstract

Our understanding of ecosystem functioning is strongly linked to the study of predator–prey relationships and food web structures. However, trophic ecology has often focused on identifying taxonomic relationships and quantifying the biomass or energy ingested by consumers, but has often failed to integrate the importance of the nutritional quality of resources in ecological dynamics. Underlying this gap is the multi‐dimensional nature of resource quality which has hampered any consensus on the definition of resource nutritional quality. In this special issue, we aimed at gathering a subset of articles exemplifying the diversity of variables by which resources quality is quantified, the diversity of research topics that can be tackled in ecology – from physiological or evolutionary aspects to ecosystem processes – and propose some perspectives on the integration of nutritional quality within broader ecological concepts. Using a semi‐automated literature analysis, we map the current landscape of the ‘resources nutritional quality' research of the last 30 years. We depict how it has been quantified through physical, biological or chemical indicators, the use of these parameters being largely dependent on the type of ecosystem studied and on the investigated ecological process. We then position the articles published in this special issue of Oikos within this landscape, showing they cover a small but relatively well representative subset of the domains of resources quality‐related issues. Articles in this special issue browse a range of individual and population‐level approaches (embracing evolutionary questions) to community related questions, include methodological issues and ecosystem‐wide approaches using trophic quality indicators as tracers of resources origin. Based on these studies and on the literature review, we identify a non‐exhaustive list of challenges and perspectives of research that we consider of highest priority in the large topic of trophic ecology.

Integrating isotopic and nutritional niches reveals multiple dimensions of individual diet specialisation in a marine apex predator

“…Integrating a nutritional dimension of individual diet specialisation could help better define nutritional generalism and establish mechanistic links, formulated around macronutrient balance, between individual fitness, foraging specialisation and its ecological outcomes. The wider adoption of nutrient‐specific approaches is a priority in trophic ecology (Danger et al, 2022 ) and linking SI with nutritional geometry more generally holds potential for a range of important questions, such as understanding the nutritional consequences (or drivers) of food use variation between populations (e.g. Manlick et al, 2019 ) or under a changing climate (e.g.…”

Ecosystem stability is determined by plant defence functional traits and population stability under mowing in a semi‐arid temperate steppe

“…Generally, the plant functional defence traits may respond to environmental changes earlier than the traits associated with acquisition and conservation of resource. In addition, plant functional defence traits offer a mechanistic link between plant physiological and ecological processes (Danger et al, 2022; Walker et al, 2022). Plant communities subjected to disturbances or herbivory have higher richness if the plant species have defence traits in comparison with communities with species ‘without’ defence traits (Endara et al, 2022; Ergon et al, 2017; Gargallo‐Garriga et al, 2020; Schaub et al, 2020).…”

“…The nutritional values not only influence livestock growth (Bergman et al, 2001), but also play defence roles in response of plants to environmental changes. For example, lignin and fibre provide mechanical support to plants, thus reducing their susceptibility to biotic stress (Danger et al, 2022; Khan et al, 2022; Xie et al, 2018). Numerous studies have focused on mean values of traits which predominantly reflect the effects of dominant species on ecosystem function (Huang et al, 2022; Xu et al, 2022).…”

Flow intermittency affects the nutritional quality of phototrophic biofilms and their capacity to support secondary production

“…Aquatic consumers generally select high‐quality resources (Marcarelli et al., 2011). Food quality depends on the elemental content of resources, such as the carbon (C):nitrogen (N) and C:phosphorus (P) ratios, and the biochemical composition, including the fatty acid (FA) profiles (Burian et al., 2018; Danger et al., 2022; Ruiz et al., 2021). In situations where only low‐quality resources are available, consumers can compensate by increasing their feeding rate to maintain their fitness (e.g., Cruz‐Rivera & Hay, 2000).…”