Pub Date : 2026-01-09DOI: 10.1016/j.ecolmodel.2025.111455
Yuichi Sato, Kazuhide Hayakawa
Lakes are globally important freshwater resources, and their sustainable management requires not only controlling eutrophication but also maintaining biological productivity and ecosystem health. In this study, we proposed a statistical method to analyze the relationships among indicators of water quality and biological resources using a food chain model combined with the Monte Carlo method. This approach overcomes the limitations of conventional mathematical models, specifically their dependence on unknown parameters and the resulting uncertainty. The method was applied to Lake Biwa to identify indicators that contribute to both water quality improvement and enhancement of biological resources including fish stocks. The results showed that the biomass ratio of planktivorous fish to phytoplankton and the integrated trophic position (iTP) were positively associated with higher trophic transfer efficiencies (TE), indicating the importance of efficient energy flow through the food chain. A higher phosphorus-to-carbon (P:C) ratio in phytoplankton was also linked to improved fish biomass and water clarity. In contrast, dissolved phosphorus (DP) concentration showed no clear relationship with phytoplankton biomass and did not serve as a useful predictor under stable nutrient loading conditions. When a 1.5-fold increase in DP loading was simulated, changes in biomass and nutrient concentrations were small, suggesting that internal nutrient recycling plays a dominant role in the phosphorus dynamics in Lake Biwa. Therefore, simply increasing nutrient inputs to enhance fish biomass is unlikely to produce the desired effects.
{"title":"Indicators for lake environmental assessment considering water quality and biological resources: Analysis using a food chain model with the Monte Carlo method","authors":"Yuichi Sato, Kazuhide Hayakawa","doi":"10.1016/j.ecolmodel.2025.111455","DOIUrl":"10.1016/j.ecolmodel.2025.111455","url":null,"abstract":"<div><div>Lakes are globally important freshwater resources, and their sustainable management requires not only controlling eutrophication but also maintaining biological productivity and ecosystem health. In this study, we proposed a statistical method to analyze the relationships among indicators of water quality and biological resources using a food chain model combined with the Monte Carlo method. This approach overcomes the limitations of conventional mathematical models, specifically their dependence on unknown parameters and the resulting uncertainty. The method was applied to Lake Biwa to identify indicators that contribute to both water quality improvement and enhancement of biological resources including fish stocks. The results showed that the biomass ratio of planktivorous fish to phytoplankton and the integrated trophic position (iTP) were positively associated with higher trophic transfer efficiencies (TE), indicating the importance of efficient energy flow through the food chain. A higher phosphorus-to-carbon (P:C) ratio in phytoplankton was also linked to improved fish biomass and water clarity. In contrast, dissolved phosphorus (DP) concentration showed no clear relationship with phytoplankton biomass and did not serve as a useful predictor under stable nutrient loading conditions. When a 1.5-fold increase in DP loading was simulated, changes in biomass and nutrient concentrations were small, suggesting that internal nutrient recycling plays a dominant role in the phosphorus dynamics in Lake Biwa. Therefore, simply increasing nutrient inputs to enhance fish biomass is unlikely to produce the desired effects.</div></div>","PeriodicalId":51043,"journal":{"name":"Ecological Modelling","volume":"514 ","pages":"Article 111455"},"PeriodicalIF":3.2,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.ecolmodel.2026.111479
Christine E. Verhille , Sebastiaan A.L.M. Kooijman
Supply-species typically eat what is available, while demand-species eat what they need, almost independently of what is available. The trait ‘supply stress’ quantifies the supply–demand spectrum, in the context of the Dynamic Energy Budget (DEB) theory. This dimensionless trait is defined as the maturity maintenance times the squared somatic maintenance, divided by the cubed assimilation. This function of DEB parameters is mostly estimated from data on growth, reproduction and life history, typically applied for fully grown individuals. Only a minority of the over 7300 species in the Add-my-Pet collection also have respiration data, combined with other data. Consistent with a set of traits that characterizes the supply/demand spectrum, birds and mammals score high on the supply stress, reptiles, amphibians, cartilaginous fish score moderate and ray-finned fish and invertebrates score low. The structure of the standard DEB model explains why species must have a low supply stress to allocate a large fraction of their assimilation to reproduction. We show this for large taxa, but also for rodents, compared to carnivorans, where rodents have a lower position in the food chain. We list and discuss ecophysiological properties that characterize the spectrum. A decade ago, the factorial aerobic scope (FAS), i.e. the ratio of the maximum and basal metabolic rate (MMR and BMR), was predicted to be high for species at the demand-end of the spectrum, and low for those at the supply-end. The aim of this paper is to test this prediction for respiration data from the literature. Our conclusion is that the FAS indeed increases for increasing supply stress, but the scatter is substantial. The FAS roughly increases from 3.2 at zero supply stress to 32 at maximum supply stress. We discuss an application of this finding for the estimation of the maturity maintenance rate coefficient from data, which is otherwise difficult with simple data. We also discuss the large scatter of respiration rates and show, with a computer simulation study of the standard DEB model, that a little scatter in food intake translates into a much larger scatter of respiration rates. Despite the scatter, the measured BMR was found to be close to the DEB-predicted field metabolic rate. This is remarkable because DEB theory makes no direct assumptions about respiration, but can still predict it exploiting the conservation laws for the chemical elements C, H, O and N. Our findings not only suggest functionalities of the aerobic scope in a wider context, but also support the concept of maturity maintenance, which is key to DEB theory, but hard to make concrete.
{"title":"The aerobic scope is clearly linked to the supply–demand spectrum as quantified by DEB theory","authors":"Christine E. Verhille , Sebastiaan A.L.M. Kooijman","doi":"10.1016/j.ecolmodel.2026.111479","DOIUrl":"10.1016/j.ecolmodel.2026.111479","url":null,"abstract":"<div><div>Supply-species typically eat what is available, while demand-species eat what they need, almost independently of what is available. The trait ‘supply stress’ quantifies the supply–demand spectrum, in the context of the Dynamic Energy Budget (DEB) theory. This dimensionless trait is defined as the maturity maintenance times the squared somatic maintenance, divided by the cubed assimilation. This function of DEB parameters is mostly estimated from data on growth, reproduction and life history, typically applied for fully grown individuals. Only a minority of the over 7300 species in the Add-my-Pet collection also have respiration data, combined with other data. Consistent with a set of traits that characterizes the supply/demand spectrum, birds and mammals score high on the supply stress, reptiles, amphibians, cartilaginous fish score moderate and ray-finned fish and invertebrates score low. The structure of the standard DEB model explains why species must have a low supply stress to allocate a large fraction of their assimilation to reproduction. We show this for large taxa, but also for rodents, compared to carnivorans, where rodents have a lower position in the food chain. We list and discuss ecophysiological properties that characterize the spectrum. A decade ago, the factorial aerobic scope (FAS), i.e. the ratio of the maximum and basal metabolic rate (MMR and BMR), was predicted to be high for species at the demand-end of the spectrum, and low for those at the supply-end. The aim of this paper is to test this prediction for respiration data from the literature. Our conclusion is that the FAS indeed increases for increasing supply stress, but the scatter is substantial. The FAS roughly increases from 3.2 at zero supply stress to 32 at maximum supply stress. We discuss an application of this finding for the estimation of the maturity maintenance rate coefficient from data, which is otherwise difficult with simple data. We also discuss the large scatter of respiration rates and show, with a computer simulation study of the standard DEB model, that a little scatter in food intake translates into a much larger scatter of respiration rates. Despite the scatter, the measured BMR was found to be close to the DEB-predicted field metabolic rate. This is remarkable because DEB theory makes no direct assumptions about respiration, but can still predict it exploiting the conservation laws for the chemical elements C, H, O and N. Our findings not only suggest functionalities of the aerobic scope in a wider context, but also support the concept of maturity maintenance, which is key to DEB theory, but hard to make concrete.</div></div>","PeriodicalId":51043,"journal":{"name":"Ecological Modelling","volume":"514 ","pages":"Article 111479"},"PeriodicalIF":3.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-05DOI: 10.1016/j.ecolmodel.2025.111471
Hang Wang , Qing Kang , Fengqin Li , Zhoupeng Chen , Xin Nie
To clarify the comprehensive impact of Transfer of Development Rights (TDR) on ecosystem services (ES), this study constructs TDR scenario simulations using Guangxi, China as the study area. First, we identified two types of TDR transfer mechanisms—urban-rural and regional—based on Chinese policies that implicitly reflect the TDR concept. Second, TDR sending and receiving areas were delineated according to urban-rural relationships and objective indicators such as the ratio of developed area to total area in each city. Third, a top-down allocation method was employed to determine the quantity of Land Development Rights (LDR) transferred. Finally, the PLUS model was used to simulate land use under the TDR scenario. For comparison, four scenarios were constructed: the Baseline Scenario (BS), Development Scenario (DS), Protection Scenario (PS), and TDR Scenario (TDR). On this basis, the InVEST model was used to estimate three ES functions—Soil Conservation (SC), Habitat Quality (HQ), and Carbon Storage (C)—while a spatial analytical geometry model was applied to measure ES coordination deviation (CDD) and the degree of comprehensive transformation (CTD). The results show that: (1) TDR flexibly reallocates construction land through spatial transfer, meeting development needs while protecting agricultural and ecological spaces, thereby effectively reducing losses in SC, HQ, and C. (2) Taking 2020 as the baseline, compared with other scenarios, TDR improves ES coordination by 0.09%, with CTD decreasing by only 0.10%. Compared with the BS, TDR increases CTD by 0.255% while reducing coordination by only 0.197%, indicating the best overall ES performance. This study demonstrates the positive effects of TDR on ES protection and provides new insights for coordinating land development and ecological conservation in regional spatial planning.
{"title":"Does transfer of development rights (TDR) enhance or suppress ecosystem services? Evidence from Southern China","authors":"Hang Wang , Qing Kang , Fengqin Li , Zhoupeng Chen , Xin Nie","doi":"10.1016/j.ecolmodel.2025.111471","DOIUrl":"10.1016/j.ecolmodel.2025.111471","url":null,"abstract":"<div><div>To clarify the comprehensive impact of Transfer of Development Rights (TDR) on ecosystem services (ES), this study constructs TDR scenario simulations using Guangxi, China as the study area. First, we identified two types of TDR transfer mechanisms—urban-rural and regional—based on Chinese policies that implicitly reflect the TDR concept. Second, TDR sending and receiving areas were delineated according to urban-rural relationships and objective indicators such as the ratio of developed area to total area in each city. Third, a top-down allocation method was employed to determine the quantity of Land Development Rights (LDR) transferred. Finally, the PLUS model was used to simulate land use under the TDR scenario. For comparison, four scenarios were constructed: the Baseline Scenario (BS), Development Scenario (DS), Protection Scenario (PS), and TDR Scenario (TDR). On this basis, the InVEST model was used to estimate three ES functions—Soil Conservation (SC), Habitat Quality (HQ), and Carbon Storage (C)—while a spatial analytical geometry model was applied to measure ES coordination deviation (CDD) and the degree of comprehensive transformation (CTD). The results show that: (1) TDR flexibly reallocates construction land through spatial transfer, meeting development needs while protecting agricultural and ecological spaces, thereby effectively reducing losses in SC, HQ, and C. (2) Taking 2020 as the baseline, compared with other scenarios, TDR improves ES coordination by 0.09%, with CTD decreasing by only 0.10%. Compared with the BS, TDR increases CTD by 0.255% while reducing coordination by only 0.197%, indicating the best overall ES performance. This study demonstrates the positive effects of TDR on ES protection and provides new insights for coordinating land development and ecological conservation in regional spatial planning.</div></div>","PeriodicalId":51043,"journal":{"name":"Ecological Modelling","volume":"514 ","pages":"Article 111471"},"PeriodicalIF":3.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-03DOI: 10.1016/j.ecolmodel.2025.111467
Kohei Oka , Akio Sohma
Anchovy (Engraulis spp.) populations are globally important fishery resources that are being increasingly threatened by rising sea temperatures, nutrient decline, and hypoxia. In this study, we developed a novel Ecopath with Ecosim (EwE) model for Japanese anchovy (Engraulis japonicus) in Osaka Bay, integrating species-specific physiological responses to water temperature, nutrient availability, and dissolved oxygen across the food web. The model successfully reproduced long-term trends in biomass and catch, validated by PREBAL diagnostics and historical data. Sensitivity analyses revealed that moderate warming (+2°C) enhanced anchovy biomass, whereas excessive warming (+3°C) and severe nutrient reduction decreased biomass through prey scarcity and hypoxia-induced mortality. Moderate warming (+1°C) or moderate nutrient enrichment (×1.5) increased Japanese anchovy biomass. Excessive warming (+3°C) decreased biomass primarily due to prey loss, while excessive nutrient enrichment (×3.0) reduced biomass mainly through hypoxia. These findings emphasize the cascading interactions among nutrient dynamics, primary production, prey availability, and predator mortality under environmental stressors. Despite uncertainties, our modeling approach provides actionable insights for integrated coastal management and climate adaptation strategies, offering a practical tool for sustaining fishery resources in a changing ocean. This study applies EwE by explicitly integrating the physiological responses of primary producers to temperature and nutrient changes, as well as the responses of consumers to temperature and hypoxia effects. By validating this integrated formulation through single-stressor analyses, it provides a robust basis for future multi-stressor applications.
凤尾鱼（Engraulis spp.）种群是全球重要的渔业资源，正日益受到海水温度上升、营养物质下降和缺氧的威胁。在这项研究中，我们为大阪湾的日本凤尾鱼（Engraulis japonicus）开发了一个新的Ecopath with Ecosim （EwE）模型，整合了物种对水温、养分有效性和食物网中溶解氧的特定生理反应。该模型成功地再现了生物量和捕获量的长期趋势，并得到了PREBAL诊断和历史数据的验证。敏感性分析显示，适度增温（+2°C）增加了凤尾鱼生物量，而过度增温（+3°C）和严重的营养减少通过猎物稀缺和缺氧导致的死亡减少了凤尾鱼生物量。适度升温（+1°C）或适度营养富集（×1.5）增加了日本凤尾鱼生物量。过度变暖（+3°C）主要由于猎物损失而减少生物量，而过度营养丰富（×3.0）主要通过缺氧减少生物量。这些发现强调了在环境压力下营养动态、初级产量、猎物可得性和捕食者死亡率之间的级联相互作用。尽管存在不确定性，但我们的建模方法为沿海综合管理和气候适应战略提供了可操作的见解，为在不断变化的海洋中维持渔业资源提供了实用工具。本研究通过明确整合初级生产者对温度和营养变化的生理反应，以及消费者对温度和缺氧影响的反应来应用EwE。通过单一压力源分析验证了这一集成公式，为未来的多压力源应用提供了坚实的基础。
{"title":"Trophic modeling of temperature, nutrient, and hypoxia dynamics on Japanese anchovy populations in Osaka Bay","authors":"Kohei Oka , Akio Sohma","doi":"10.1016/j.ecolmodel.2025.111467","DOIUrl":"10.1016/j.ecolmodel.2025.111467","url":null,"abstract":"<div><div>Anchovy (<em>Engraulis</em> spp.) populations are globally important fishery resources that are being increasingly threatened by rising sea temperatures, nutrient decline, and hypoxia. In this study, we developed a novel Ecopath with Ecosim (EwE) model for Japanese anchovy (<em>Engraulis japonicus</em>) in Osaka Bay, integrating species-specific physiological responses to water temperature, nutrient availability, and dissolved oxygen across the food web. The model successfully reproduced long-term trends in biomass and catch, validated by PREBAL diagnostics and historical data. Sensitivity analyses revealed that moderate warming (+2°C) enhanced anchovy biomass, whereas excessive warming (+3°C) and severe nutrient reduction decreased biomass through prey scarcity and hypoxia-induced mortality. Moderate warming (+1°C) or moderate nutrient enrichment (×1.5) increased Japanese anchovy biomass. Excessive warming (+3°C) decreased biomass primarily due to prey loss, while excessive nutrient enrichment (×3.0) reduced biomass mainly through hypoxia. These findings emphasize the cascading interactions among nutrient dynamics, primary production, prey availability, and predator mortality under environmental stressors. Despite uncertainties, our modeling approach provides actionable insights for integrated coastal management and climate adaptation strategies, offering a practical tool for sustaining fishery resources in a changing ocean. This study applies EwE by explicitly integrating the physiological responses of primary producers to temperature and nutrient changes, as well as the responses of consumers to temperature and hypoxia effects. By validating this integrated formulation through single-stressor analyses, it provides a robust basis for future multi-stressor applications.</div></div>","PeriodicalId":51043,"journal":{"name":"Ecological Modelling","volume":"514 ","pages":"Article 111467"},"PeriodicalIF":3.2,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.ecolmodel.2025.111460
Anne A. Innes-Gold , Peter Houk , Tye L. Kindinger , Brett M. Taylor , Austin Humphries
Aquaculture-based fisheries enhancement (i.e., restocking) involves releasing hatchery-reared fish into the wild to support depleted populations and sustain fisheries. However, the benefits of these activities can be difficult to detect. We created a theoretical model to evaluate the potential benefits of restocking initiatives for a prominent forktail rabbitfish (Siganus argenteus) fishery in Guam. Forktail rabbitfish have three distinct life stages making them ideal for a discrete stage-structured modeling approach: mañahak (recruits), dagge (juveniles), and hiteng kahlao (adults). We modelled restocking scenarios whereby mañahak were harvested for grow-out and subsequently reintroduced into the population as dagge, thereby reinforcing the life stage transition with the lowest natural survival probability. We found that restocking had variable impacts on the population structure and resilience that were dependent on the intensity of exploitation. Under full exploitation, restocking improved resilience by shifting the most sensitive life-stage transition from mañahak-to-dagge to dagge-to-hiteng kahlao. Only under low-to-intermediate fishing could restocking reverse the population trajectory from a declining trend to a growing one. Restocking 2–10 % of the unfished biomass (B0) allowed the population to sustain 12–25 % higher yields while still maintaining the 50 % B0 benchmark. Overall, fishing and natural reproduction were consistently the strongest determinants of population structures, transitions, and trajectories; however, restocking augmented population resilience and improved fisheries yields. This study demonstrates the potential viability of restocking in combination with fishing regulations to enhance fisheries yield in a culturally important fishery.
{"title":"Evaluating rabbitfish restocking potential in support of Guam’s coastal fisheries","authors":"Anne A. Innes-Gold , Peter Houk , Tye L. Kindinger , Brett M. Taylor , Austin Humphries","doi":"10.1016/j.ecolmodel.2025.111460","DOIUrl":"10.1016/j.ecolmodel.2025.111460","url":null,"abstract":"<div><div>Aquaculture-based fisheries enhancement (i.e., restocking) involves releasing hatchery-reared fish into the wild to support depleted populations and sustain fisheries. However, the benefits of these activities can be difficult to detect. We created a theoretical model to evaluate the potential benefits of restocking initiatives for a prominent forktail rabbitfish (<em>Siganus argenteus</em>) fishery in Guam. Forktail rabbitfish have three distinct life stages making them ideal for a discrete stage-structured modeling approach: mañahak (recruits), dagge (juveniles), and hiteng kahlao (adults). We modelled restocking scenarios whereby mañahak were harvested for grow-out and subsequently reintroduced into the population as dagge, thereby reinforcing the life stage transition with the lowest natural survival probability. We found that restocking had variable impacts on the population structure and resilience that were dependent on the intensity of exploitation. Under full exploitation, restocking improved resilience by shifting the most sensitive life-stage transition from mañahak-to-dagge to dagge-to-hiteng kahlao. Only under low-to-intermediate fishing could restocking reverse the population trajectory from a declining trend to a growing one. Restocking 2–10 % of the unfished biomass (B<sub>0</sub>) allowed the population to sustain 12–25 % higher yields while still maintaining the 50 % B<sub>0</sub> benchmark. Overall, fishing and natural reproduction were consistently the strongest determinants of population structures, transitions, and trajectories; however, restocking augmented population resilience and improved fisheries yields. This study demonstrates the potential viability of restocking in combination with fishing regulations to enhance fisheries yield in a culturally important fishery.</div></div>","PeriodicalId":51043,"journal":{"name":"Ecological Modelling","volume":"514 ","pages":"Article 111460"},"PeriodicalIF":3.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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