Patterns Of Resource Use Research Articles

Seasonal Patterns of Resource Use Within Natural Populations of Burying Beetles.

For organisms in temperate environments, seasonal variation in resource availability and weather conditions exert fluctuating selection pressures on survival and fitness, resulting in diverse adaptive responses. By manipulating resource availability on a local spatial scale, we studied seasonal patterns of resource use within natural populations of burying beetles Nicrophorus vespilloides in a Norfolk woodland. Burying beetles are necrophagous insects that breed on vertebrate carcasses. They are active in Europe between April and October, after which they burrow into the soil and overwinter. Using breeding and chemical analyses, we compared the fecundity and physiological state of beetles that differed in their seasonal resource use. We found seasonal variation in carrion use by wild burying beetles and correlated differences in their reproductive success and cuticular hydrocarbon profiles. Our results provide novel insight into the seasonal correlates of behaviour, physiology and life history in burying beetles.

How can we measure resource quality when resources differ in many ways? Deconstructing shelter quality in a social fish.

Resource quality is an important concept in ecology and evolution that attempts to capture the fitness benefits a resource affords to an organism. Yet "quality" is a multivariate concept, potentially affected by many variables pertaining to the resource, its surroundings, and the resource chooser. Researchers often use a small number of proxy variables to simplify their estimation of resource quality, but without vetting their proxies against a wider set of potential quality estimators this approach risks overlooking potentially important characteristics that can explain patterns of resource use in their study systems. Here we used Neolamprologus multifasciatus, a group-living cichlid fish that utilizes empty snail shells as shelter resources, to examine how shells were used by, and partitioned among, group members in relation to a range of attributes, including shell size, intactness, texture, spatial position, and usage by heterospecifics. This approach generated a comprehensive picture of what characteristics contribute to the attractiveness and quality of each shell resource, confirming the importance of two previously proposed shell characteristics, size and intactness, but highlighting the influences of other unexplored variables, including shell spatial position and usage by heterospecifics. We also present a generally applicable "resource attractiveness index" as a means to estimate resource quality based on resource choice data. This index incorporates information from any number of resource characteristics and is of particular use when researchers wish to quantify resource value, but many characteristics jointly contribute to the value and attractiveness of the resource.

Patterns in Food Resource Use by Butterflies in an Experimental Macrocosm

Patterns in Food Resource Use by Butterflies in an Experimental Macrocosm

High-throughput sequencing and fatty acid profile analyses of the Black Amur bream (Megalobrama terminalis) reveal variation in dietary niche associated with geographic segregation.

Fish dietary niche is a core focus, and it reflects the diversity of resources, habitats, or environments occupied by a species. However, whether geographic segregation among different populations triggers dietary diversification and concomitant fish niche shift remains unknown. In the present study, we selected the Black Amur bream (Megalobrama terminalis) is a migratory fish species that plays an important role in the material transfer and energy cycling of river ecosystems, inhabiting southern China drainage with multiple geographic populations. Here, we utilized the combined analyses of 18S rDNA high-throughput sequencing in fish gut contents and fatty acid (FA) in muscle tissues to evaluate potential spatial patterns of habitat and resource use for M. terminalis in three rivers of southern China. Our results showed that prey items of the Xijiang (XR) population (Pearl River) exhibited the highest species diversity and richness among the three geographic populations. Moreover, diet composition of M. terminalis was affected by spatial differences associated with geographic segregation. Analyses of FA biomarkers indicated that the highest levels of C16:0, C18:3n-3, and C18:2n-6c were found in Wanquan (WS) population (Wanquan River). The XR population exhibited a distinct FA profile characterized by higher amounts of arachidonic acid (ARA) and docosahexaenoic acid (DHA). The Moyang (MY) population (Moyang River) acted as the linkage between WS and XR populations and consisted of middle levels of saturated FAs (SFAs) and polyunsaturated FAs (PUFAs). The XR population displayed a greater FA niche width compared with WS population. Furthermore, we observed a close positive relationship between the niche width and α-diversity indices of dietary resources for FA proflies. Our study provides valued information to develop different conservation strategies among different populations and improve fisheries management for M. terminalis and other endemic species in local rivers.

Factors Influencing Forest Dependency on the Gola Rainforest Reserve in Sierra Leone

Purpose: Forests are under intense human pressure due to a high level of dependency. Understanding socioeconomic and demographic incentives surrounding forest dependence is critical to mitigating the adverse impacts of forest degradation in Africa. Therefore, this study examines the factors promoting household forest dependence in Sierra Leone's Gola Rainforest Reserve through four research questions: (1) What is the contribution of forest income relative to total household income? (2) What are the key sources of relative forest income? (3) How do gender, age, and education influence forest dependency? (4) What factors drive dependence on forest resources?
 Methodology: The study's target population was rural households living near the Gola Rainforest Reserve in Gaura and Tunkia Chiefdoms in the Kenema district. The study used convenience sampling. A questionnaire and an interview guide were used for data collection. It drew from 101 survey responses analyzed using descriptive and inferential statistics, binary logistic regression on S.P.S.S., and then —seven expert interviews and three focus group discussions explored with thematic analysis on Google Docs. The study used tables and figures for data presentation.
 Findings: The study's results showed four key findings. First, forest income accounts for 46% of monthly household income in the sampled community. Second, the top five sources of forest income are cocoa (74%), moringa tea (9%), timber wood (4%), forest spices (4%), and forest fruit and vegetables (3%). Third, age, education, and gender influence forest dependence. Fourth, livelihood and direct consumption are the key factors driving dependence on forest resources. Therefore, the study recommended that decision-makers and conservationists consider socioeconomic factors like gender, age, education, and livelihood when designing forest management projects, strategies, or policies. 
 Unique Contribution to Theory, Practice, and Policy: The study’s outcome contributes to the growing literature on forest dependency. It provides key insights into the significant contribution of forest resources to household income. Analyzing the influence of socio-demographic factors, like gender, age, and education, on forest resources enhances the understanding of resource-use patterns. This study allows forest conservationists, government decision-makers, and academics to develop projects, policies, and strategies from an informed perspective, considering socio-economic realities, to promote sustainable forest management practices in Sierra Leone and other developing countries to mitigate deforestation.

Stable Isotope Analysis of Manatee Vibrissae to Investigate Individual Patterns of Resource Use in the Northern Gulf of Mexico

Stable Isotope Analysis of Manatee Vibrissae to Investigate Individual Patterns of Resource Use in the Northern Gulf of Mexico

Practice as you Teach: Comparing Ordering Practices Between Shared and Physician-Only Visits in Academically Affiliated Community Emergency Departments

BackgroundConsiderable variability exists in emergency physicians’ (EPs) rates of resource utilization, which may cluster in distinct patterns. However, previous studies have focused on academic and tertiary care centers, and it is unclear whether similar patterns exist in community practice. ObjectiveOur aim was to examine whether EPs practicing in community emergency departments (EDs) have practice patterns similar to those of academic EDs. Secondarily, we sought to investigate the effects of shared visits with advanced practice professionals and residents. MethodsThis was a retrospective study of two community EDs affiliated with an academic network. There were 62,860 visits among 50 EPs analyzed from October 1, 2018 through January 31, 2020 for rates of advanced imaging, admission, and shared visits. To classify practice patterns, we used a Gaussian Mixture Model (GMM), with groups and covariance determined by Bayesian Information Criteria. ResultsOur GMM revealed three groups. The largest had homogeneous patterns of resource use (n = 28; 50% were female; years of experience: 7; interquartile range [IQR] 2–11; advanced imaging: 28%; admission: 19%; shared: 34%), a small group with lower resource use (n = 4; 0% were female; years of experience: 6; IQR 4–10; advanced imaging: 28%; admission: 16%; shared: 8%), and a modest high-resource group (n = 18; 28% female; years of experience: 5; IQR 2–16; advanced imaging: 34%; admission: 23%; shared: 43%). Rates of shared visits had little direct correlation with imaging (r2 = 0.045) or admission (r2 = 0.093), and rates of imaging and admission were weakly correlated (r2 = 0.242). ConclusionsOur data suggest that community EPs may have multiple patterns of resource use, similar to those in academic EDs.

Accelerometry reveals limits to use of an energy-saving anthropogenic food source by a threatened species: A case of Carnaby's cockatoos (Zanda latirostris) and canola.

The use of anthropogenic resources is becoming increasingly common as species adapt to human-induced environmental changes, but their use can expose species to new risks. Understanding how animals exploit these resources is important for guiding conservation management, particularly where species are threatened. The introduction of canola cropping to breeding areas of endangered Carnaby's cockatoo (Zanda latirostris) has been attributed to an increase in the birds' reproductive success; however, the seed may be protein-limiting for nestling growth and its use by cockatoos has been implicated in the emergence of a new disease. We used high-resolution accelerometer-capable GPS tags to track eight birds. Accelerometer data were used to calculate overall dynamic body acceleration (ODBA), a proxy for energy expenditure, and to identify and quantify canola and native vegetation foraging behaviours. We used linear mixed models to determine which factors affected patterns of resource use and to determine whether, and to what extent, canola use was associated with reduced energetic and movement costs. We then compared the energetic content of canola seed and native food sources to inform patterns of behaviour and habitat use revealed by our tracking data. Use of canola was associated with reduced movement costs and energy expenditure. However, there was an apparent reluctance to increase foraging on canola above a threshold of time, even when conditions reduced time available to utilise native food sources. While anthropogenic resources may appear to improve population trends in some cases, careful investigations of patterns of resource use are necessary to guide appropriate conservation management efforts. For Carnaby's cockatoos, conservation efforts should focus on retention, protection and expansion of native food sources.

An analysis of the compliance of the environmental protection and waste management principles with the circular economy principles

Subject. This article discusses Russia's policy in the field of ecology. Objectives. The article aims to justify the need for a transition to cyclical patterns of resource use. Methods. For the study, I used the methods of content and comparative analyses. Results. The article finds that most of the principles of the basic cycle economy are enshrined in Russian legislation, which indicates Russia's readiness to implement sustainable development models. Conclusions and Relevance. The results of the study can be used in the development of federal and regional laws regulating environmental protection relations. The problem of transition to a circular economy is relevant in the context of an increase in the volume of production and consumption waste, as well as a decrease in the availability of natural resources.

Sources of intraspecific variation in the isotopic niche of a semi-aquatic predator in a human-modified landscape.

Intraspecific variation modulates patterns of resource use by species, potentially affecting the structure and stability of food webs. In human-modified landscapes, habitat disturbance modifies trophic interactions and intraspecific niche variation, impacting population persistence. Here, we investigated the relationship of sex, ontogeny, and habitat factors with the trophic niche of Caiman crocodilus in an agricultural landscape. We evaluated temporal variation in the trophic niche parameters using carbon and nitrogen stable isotope analysis from different body tissues. We found that caimans exploit the same carbon and nitrogen pools through time, with low isotopic variability between seasons, partly due to the slow isotope turnover rates of tissues in crocodilians. Conversely, the trophic niche of caimans varied across habitats, but with no evidence of a difference between natural and anthropogenic habitats. It apparently results from the influence of habitat suitability, connectivity, and caiman movements during the foraging. Our findings highlight the broader niches of juvenile caimans relative to adults, possibly in response of territorialism and opportunistic foraging strategy. Although using similar resources, females had a larger niche than males, probably associated with foraging strategies during nesting. Considering the sex and body size categories, caimans occupied distinct isotopic regions in some habitats, indicating apparent niche segregation. Ontogenetic trophic shifts in the isotopes (δ13C and δ15N) depended on sex, leading to resource partitioning that can potentially reduce intraspecific competition. Decision-makers and stakeholders should consider the trophic dynamics of sex and body size groups for the sustainable management and conservation of caiman populations, which implies in the maintenance of wetland habitats and landscape heterogeneity in the Formoso River floodplain.

An analysis of the resource use and costs of febrile neutropenia events in pediatric cancer patients in Australia.

Febrile neutropenia (FN) in children with cancer generally requires in-hospital care, but low-risk patients may be successfully managed in an outpatient setting, potentially reducing the overall healthcare costs. Updated data on the costs of FN care are lacking. A bottom-up microcosting analysis was conducted from the healthcare system perspective using data collected alongside the Australian PICNICC (Predicting Infectious Complications of Neutropenic sepsis In Children with Cancer) study. Inpatient costs were accessed from hospital administrative records and outpatient costs from Medicare data. Costs were stratified by risk status (low/high risk) according to the PICNICC criteria. Estimated mean costs were obtained through bootstrapping and using a linear model to account for multiple events across individuals and other clinical factors that may impact costs. The total costs of FN care were significantly higher for FN events classified as high-risk ($17,827, 95% confidence interval [CI]: $17,193-$18,461) compared to low-risk ($10,574, 95% CI: $9818-$11,330). In-hospital costs were significantly higher for high-risk compared to low-risk events, despite no differences in the cost structure, mean cost per day, and pattern of resource use. Hospital length of stay (LOS) was the only modifiable factor significantly associated with total costs of care. Excluding antineoplastics, antimicrobials are the most commonly used medications in the inpatient and outpatient setting for the overall period of analysis. The FN costs are driven by in-hospital admission and LOS. This suggests that the outpatient management of low-risk patients is likely to reduce the in-hospital cost of treating an FN event. Further research will determine if shifting the cost to the outpatient setting remains cost-effective overall.

Evaluating the current practice of therapeutic positioning in neurological rehabilitation: a qualitative interview study

Background/Aims Therapeutic positioning is believed to enable the achievement of a good postural alignment, optimise rehabilitation and prevent the complications of immobility. It is considered important in the management of people with physical neurological impairments, but achieving a favourable position in a bed can be challenging. There is little evidence to inform present practice. Therefore, this study explored staff views and experiences of bed positioning practice on a regional neurological rehabilitation unit. Methods Face-to-face, semi-structured interviews were completed with a purposive sample of nurses, physiotherapists and occupational therapists working on a neurological rehabilitation unit. The interviews were audio recorded, transcribed and analysed using inductive thematic analysis. Results A total of 12 participants completed an interview and six themes were identified relating to positioning practice. An interaction of four of these themes (patient needs, staff role, communication and knowledge) influenced a fifth theme of staff experiences. The sixth theme of practical positioning resources identified a pattern of resource use within current practice. Conclusions Positioning was recognised as integral to rehabilitation, and staff experiences were influenced by the interaction of a range of factors. The participants’ views and experiences around practical positioning resources provide a valuable new insight into positioning practice. Further research is needed to evaluate these resources.

The resource (in)sufficiency of the Caribbean: analyzing socio-metabolic risks (SMR) of water, energy, and food

IntroductionSocio-metabolic risks (SMRs) are systemic risks associated with the availability of critical resources, the integrity of material circulation, and the distribution of their costs and benefits in a socio-ecological system. For resource-stressed systems like small island nations, understanding trade-offs and synergies between critical resources is not only crucial, but urgent. Climate change is already putting small islands at high risk through more frequent and intense extreme weather events, changing precipitation patterns, and threats of inundation with future sea-level rise.MethodsThis study compares the shifting resource-baseline for 14 Caribbean island nations for the year 2000 and 2017. We analyze water, energy, and food (WEF) and their nexus through the lens of SMRs, using indicators related to their availability, access, consumption, and self-sufficiency.ResultsOur findings point to the decreasing availability of all three resources within the Caribbean region. Meanwhile, between 2000 and 2017, consumption levels have increased by 20% with respect to water (from 230 to 275 m3/cap/yr) and primary energy (from 89 to 110 GJ/cap/yr), and 5% for food (from 2,570 to 2,700 kcal/cap/day). While universal access to these resources increased in the population, food and energy self-sufficiency of the region has declined.DiscussionCurrent patterns of resource-use, combined with maladaptive practices, and climate insensitive development—such as coastal squeeze, centralized energy systems, and trade policies—magnify islands' vulnerability. Disturbances, such as climate-induced extreme events, environmental changes, financial crises, or overexploitation of local resources, could lead to cascading dysfunction and eventual breakdown of the biophysical basis of island systems. This research is a first attempt at operationalizing the concept of SMRs, and offers a deeper understanding of risk-related resource dynamics on small islands, and highlights the urgency for policy response.

Patterns of care and health care resource use among Medicaid-enrolled women with recurrent or metastatic cervical cancer.

BACKGROUND: Cervical cancer is a public health challenge and remains a disease with high unmet need. Previous real-world studies demonstrated significant variability in treatments for patients with recurrent or metastatic cervical cancer (r/mCC). A large proportion of patients with cervical cancer are insured through Medicaid; however, previous studies examining treatment patterns for r/mCC have not included Medicaid patients. As the r/mCC treatment landscape continues to evolve, there is a need to understand current real-world unmet need among patients with r/mCC enrolled in Medicaid. OBJECTIVE: To evaluate treatment patterns and health care resource utilization (HCRU) among Medicaid-enrolled women with r/mCC. METHODS: This is a retrospective analysis of nationwide Medicaid claims to assess patient characteristics, treatment patterns, and HCRU among patients with r/mCC between 2016 and 2019. First-line treatment (1L) for r/mCC was defined by the first administration of systemic therapy without concomitant radiation or surgery. Patient characteristics, treatment patterns, and HCRU were characterized by line of therapy. RESULTS: A total of 3,375 eligible adult female patients initiated systemic treatment for r/mCC between 2016 and 2019. Mean age at treatment initiation was 52.9 (SD ± 12.8) years. Nearly 1,300 (1,294, 38.3%) women had evidence of receiving second-line treatment (2L), with nearly one-third (N = 420) of those also having evidence of third-line treatment. The majority (60.5%) of 1L regimens were doublet chemotherapy ± bevacizumab, consistent with treatment guidelines. In contrast, no clear preferred treatment choice was observed among patients receiving 2L or later (2L+) therapy. Notably, immunotherapy accounted for 21.6% of treatment regimens in 2L/3L overall, with its use increasing substantially over time (<6% in 2016 to 40.8% in 2019). Despite increased use of immunotherapy, however, most patients did not remain on treatment for prolonged durations (immunotherapy median duration 2.2 months vs 2.4 months for nonimmunotherapy; P = 0.5). Across most HCRU measures (inpatient admissions, outpatient visits, emergency department visits, and pharmacy claims), 2L+ patients had significantly less utilization per patient compared with 1L patients in unadjusted analyses. CONCLUSIONS: This analysis found that the majority of Medicaid patients with r/mCC received guideline-recommended standard of care in 1L between 2016 and 2019. However, there was no clear standard of care for patients with 2L+ r/mCC enrolled in Medicaid over this time period. Although immunotherapy use is increasing, short durations of treatment suggest a potential unmet medical need among this population. New therapies should provide meaningful clinical benefit without significant increase in HCRU for Medicaid enrollees needing treatment for r/mCC. DISCLOSURES: Dr Leath has received consulting fees from Seagen Inc. for service on Scientific Advisory Boards, cervical cancer research funding from Agenus, Rubius Therapeutics, and Seagen Inc., and funding from the NCI UG1 CA23330 and P50 CA098252. Dr Ting and Dr Zhang are employees and stock owners of Seagen Inc. Mr Fiori and Dr Pauly are current employees and Ms Nysenbaum is a former employee of Manatt Health Strategies, which received funding from Seagen Inc. to conduct the study described here. Manatt Health Strategies has also previously received consulting fees from other pharmaceutical companies that they are not permitted to publicly disclose. This research was funded by Seagen Inc. Seagen Inc. conceptualized the study approach, methodology, and contributed to article writing and review but was not involved in data acquisition, manipulation, or analysis.

Patterns of Distress and Supportive Resource Use by Healthcare Workers During the COVID-19 Pandemic

Introduction:Healthcare workers (HCWs) are at increased risk of burnout, post-traumatic stress injury and suicide, compared to the public. Long-lasting increases in HCW distress are reported following pandemics. Such occupational stress can negatively impact individuals, organizations, and the overall healthcare system. Understanding HCW distress and needs can inform the development of resources to mitigate negative outcomes. Staff wellness data was gathered from a large academic health center during the COVID-19 pandemic, as part of a quality improvement project seeking to support staff wellbeing. Longitudinal trends of distress and preferences related to support were shared with leadership.Method:Monthly wellness assessments were sent to hospital staff via email. Assessments included screens for burnout, anxiety, depression and posttraumatic stress, questions regarding types of resources accessed, and open-ended questions regarding staff needs. Surveys were voluntary and confidential. Participants could provide their email to receive tailored resources based on individual results. Survey data was analyzed longitudinally to identify trends of distress over time.Results:A total of 2,518 wellness assessments were completed from April 2020-July 2021. An average of ~167 (range 17 – 946) HCWs responded per month and 638 staff provided their email addresses to receive a response; 497 of these completed assessments multiple times. The proportion of positive screens were, on average, 44%, 29%, 31% and 53%, for anxiety, depression, post-traumatic stress and burnout, respectively. Anxiety and post-traumatic stress scores decreased from April-August, then increased from September. The most reported source of support accessed was family/friends; ~40% of responders had not accessed formal mental health support.Conclusion:When COVID-19 cases decreased and stay-at-home mandates were lifted, HCW distress was reduced. Burnout trended upwards through the pandemic. Peer/family support remained favored compared to formal mental health support, suggesting the importance to HCW of social support. HCW reported a preference for convenient access to supportive resources.

Identification of Phytoplankton-Based Production of the Clam Corbicula japonica in a Low-Turbidity Temperate Estuary Using Fatty Acid and Stable Isotope Analyses

The brackish water clam, Corbicula japonica, acts as an ecosystem engineer in estuaries. To identify its resource-use patterns in the low-turbidity temperate Seomjin River estuary of Korea, we analyzed stable isotope and fatty acid (FA) biomarkers to differentiate allochthonous and autochthonous dietary sources, and examined the effects of clam size, salinity gradient, and season. The δ13C and δ15N values were consistent across the three factors. The δ13C values of the clams were similar to those of both riverine- and estuarine-suspended particulate organic matter (R- and E-SPOM), while their δ15N values were 2–4‰ higher, indicating an equal contribution of both sources to the clam diet. Biogeochemical proxies and FA compositions of SPOM indicate that estuarine phytoplankton significantly contribute to the E-SPOM pool. Moreover, the similarity in FA profiles between Corbicula and E-SPOM indicates that phytoplankton-derived organic matter is the primary source of nutrition for the clam, with minimal impact from growth, salinity gradient, or seasonal changes. Our study suggests that in low-turbidity estuaries with high phytoplankton production, allochthonous organic matter makes a negligible contribution to clam nutrition, compared to high-turbidity estuaries. This finding could provide insights into the variations in the trophic structure of estuarine food webs across diverse regions.

No ‘Wearing-Off Effect’ Seen with Fremanezumab in the Real-World: Retrospective, Claims-Based Analysis of Migraine-Related Healthcare Resource and Acute Medication Use (P12-12.005)

No ‘Wearing-Off Effect’ Seen with Fremanezumab in the Real-World: Retrospective, Claims-Based Analysis of Migraine-Related Healthcare Resource and Acute Medication Use (P12-12.005)

Energy regimes help tackle limitations with the prehistoric cultural‐phases approach to learn about sustainable transitions: Archaeological evidence from northern Spain

ABSTRACTHuman societies face challenges in transitioning towards low‐carbon economies and sustainable management of land use and natural resources. Documenting and learning from past transitions helps policy‐makers cope with such challenges. The agricultural revolution in Cantabrian Spain (ca. 7000 cal a bp) was one major adaptation of hunter‐gatherers to a changing environment that started with the Last Glacial Maximum (ca. 24 000 cal a bp) and lasted until the Mid‐Holocene (ca. 5300 cal a bp). Classic approaches to documenting prehistoric cultural timelines are based on manufacturing and technology, thus limited in their ability to describe the sustainability of past societies. Energy regimes, a functional societal approach independent from time, investigate and consider patterns of resource and energy use in various cohabiting and cooperating cultural phases. To examine past energy regimes, a database of archaeological remains was compiled to document four indicators: mobility, economy, overexploitation and societal complexity. Statistical analyses were conducted to elucidate trends, changes and continuity in subsistence strategies by hunter‐gatherers and sedentary societies. Results show that energy regimes act as a complement to cultural phases, adding novel functional analyses of past societies to cultural stratigraphy units common in archaeology, shedding light on the sustainability of past societal transitions.

From the light blue sky to the dark deep sea: Trophic and resource partitioning between epipelagic and mesopelagic layers in a tropical oceanic ecosystem

The connection between epipelagic and deep-sea mesopelagic realms controls a variety of ecosystem processes including oceanic carbon storage and the provision of harvestable fish stocks. So far, these two layers have been mostly addressed in isolation and the ways they connect remain poorly understood. Furthermore, both systems are affected by climate change, exploitation of resources, and increasing pervasion of pollutants. Here we use bulk isotopes of δ13C and δ15N of 60 ecosystem components to evaluate the trophic linkage between epipelagic and mesopelagic ecosystems in warm oligotrophic waters. Additionally, we we conducted a comparison of isotopic niche sizes and overlaps across multiple species to evaluate how environmental gradients between epipelagic and mesopelagic ecosystems shape ecological patterns of resource use and competition between species. Our database comprises siphonophores, crustaceans, cephalopods, salpas, fishes, and seabirds. It also includes five zooplankton size classes, two groups of fish larvae, and particulate organic matter collected at different depths. Through this wide taxonomic and trophic variety of epipelagic and mesopelagic species, we show that pelagic species access resources originating from different food sources, mostly autotrophic-based (epipelagics) and microbial heterotrophic-based (mesopelagics). This leads to a sharp trophic dissimilarity between vertical layers. Additionally, we show that trophic specialization increases in deep-sea species and argue that food availability and environmental stability are among the main drivers of this pattern. Finally, we discuss how the ecological traits of pelagic species highlighted in this study can respond to human impacts and increase their vulnerability in the Anthropocene.

Resource Use among Six Commercial Fish Species from the South-Eastern Gill Net Fisheries, Korea

Dietary habits and inter-specific differences in resource use among six commercial fish species, Chelidonichthys spinosus, Cleisthenes pinetorum, Glyptocephalus stelleri, Hexagrammos otakii, Lophius litulon, and Sebastes schlegelii, collected from the southern coast of the East Sea, Korea, were analyzed using stomach content and stable isotope analyses. Teleosts were the main prey items for C. pinetorum and L. litulon, while both crabs and teleosts contributed to the diets of C. spinosus and S. schlegelii. Glyptocephalus stelleri mainly consumed polycheates and carid shrimps, and H. otakii mostly ingested crabs. The composition of prey items was significantly different in the diets of the six fish species. Further, carbon (δ13C) and nitrogen (δ15N) stable isotope values were significantly different among the six species, indicating different trophic positions. L. litulon, C. pinetorum, and S. schlegelii had narrow niches, whereas C. spinosus, G. stelleri, and H. otakii had relatively wider niches. This study demonstrated differences in patterns of food resource use among the six fish species that were categorized into two patterns of resource use according to their main prey items: diet diversity, trophic niche width, and trophic position. These results could contribute to the understanding of trophic relationships among fish species inhabiting the East Sea, Korea.