The southem Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an eco...The southem Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. Atrophic mass-balance model of the southern Yellow Sea during 2000-2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to 〉V was 5.0%, 5.7%, 18.5%, and 19.7%-20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum＇s ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.展开更多
To understand trophic interactions and the precise ecological role of each predatory species,it is important to know which arthropod and plant resources are used by generalist predators in agroecosystems.Molecular app...To understand trophic interactions and the precise ecological role of each predatory species,it is important to know which arthropod and plant resources are used by generalist predators in agroecosystems.Molecular approaches,such as the use of high-throughput sequencing(HTS),play a key role in identifying these resources.This study develops a multiprimer metabarcoding approach for screening the most common trophic interactions of two predatory arthropods with contrasting morphologies,Rhagonycha fulva(Coleoptera:Cantharidae)and Anthocoris nemoralis(Hemiptera:Anthocoridae)collected from a peach crop.To reduce the time and cost of this metabarcoding approach,we first evaluated the effect of using two different predator-pools of different size(10 and 23 individuals of the same species).We also used our system to analyze the performance of one and two primer pairs in the same library.Our results show that the analysis of 23 individuals together with the use of two primer pairs in the same library optimize the HTS analysis.Using these best-performing conditions,we then analyzed the entire bodies of field-collected predators as well as the washing solutions used to clean the insect bodies.We were able to identify both gut content(i.e.,diet)and external pollen load(i.e.,on the insects’bodies).This study also demonstrates the importance of washing predatory insects’bodies prior to HTS analysis when the target species have a considerable size(>10 mm)and hairy structures.This metabarcoding approach has significant potential for the study of trophic links in agriculture,revealing expected and unexpected trophic relationships.展开更多
Dear Editor,Life-history studies including dietary preferences and trophic interactions are essential for understanding community ecology in lizards(Pianka,1986).The family Agamidae is one of the largest in terms of s...Dear Editor,Life-history studies including dietary preferences and trophic interactions are essential for understanding community ecology in lizards(Pianka,1986).The family Agamidae is one of the largest in terms of species diversity and occurs in a variety of habitats(Uetz et al.,2024).展开更多
Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.Ho...Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.However,their effects are poor because of the complex water and temperature conditions,especially under sodic conditions.Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM,providing a new direction for promoting high-efficiency straw conversion into SOM.In this study,we conducted a^(13)C-labeled straw degradation experiment using small molecules derived from lignin(LSMs)and humus(HSMs)as activators,investigating their effects on the microbial communities and formation of newly formed mineral-associated(^(13)C-MAOM)and particulate(^(13)C-POM)organic matter from^(13)C-labeled straw in both sodic and non-sodic soils.The^(13)C-labeled straw was mainly converted into^(13)C-MAOM,accounting for 73.97%–92.67%of the newly formed SOM.Biopolymer-derived small molecules decreased the exchangeable sodium percentage(ESP),but increased contents of^(13)C-MAOM and^(13)C-POM by shifting microbial communities,strengthening microbial cross-trophic interactions,enhancing enzyme activities,and increasing microbial residues in both soils.Addition of HSMs had greater impacts on^(13)C-MAOM formation than LSM addition.The^(13)C-MAOM and^(13)C-POM formation negatively correlated with ESP,but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils.Our results suggest that biopolymer-derived small molecules promote^(13)C-MAOM and^(13)C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers.Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions.展开更多
A mass-balanced Ecopath model presents a quantitative description of the trophic structure,fl ow of energy and trophic interaction among ecological groups of an ecosystem.The Ecopath with Ecosim(EwE)modeling program(V...A mass-balanced Ecopath model presents a quantitative description of the trophic structure,fl ow of energy and trophic interaction among ecological groups of an ecosystem.The Ecopath with Ecosim(EwE)modeling program(Version 6.5)was used to develop a preliminary trophic model for a tropical freshwater reservoir.The total fi sh biomass was 6.245 t/km 2 and the highest trophic level of the reservoir was 3.362(for snakehead).The ecosystem is phytoplankton based because primary producers originated 68%and detritus originated 32%of the total fl ow from lower trophic level.The gross effi ciency of the fi shery was 0.004,suggesting the ineffi ciency of the system.The positive eff ect of phytoplankton and detritus on most of the other groups were evident from mixed trophic analysis while moderately higher ecotrophic effi ciency(EE)of phytoplankton shows the ecosystem’s potential bottom-up control.The competition for the same resources among diff erent groups was also obvious.The ratio of primary production/respiration(1.969)suggests that the ecosystem is at the developing stage and utmost contemplation should be given to concerned human activities.The low value of relative ascendancy(30.13)and overhead(69.87)reveals the stability of the ecosystem and some degrees of maturity.It also predicts the presence of signifi cant strength in reserve of the system to withstand or overcome any perturbation.However,ecologically sustainable resource management plans should be implemented to ensure the sustainability of this reservoir resources.展开更多
Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study e...Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study ecology from genes to the biosphere. Among this trend, N:P stoichiometry is used actively in ecological interactions since nitrogen (N) and phosphorus (P) are the two most important elements in most ecosystems. This article reviews the application of N:P stoichiometry to the studies of ecological problems at different levels, including ecosystem, community and species. Meanwhile, we also provide the cellular basis of N:P stoichiometry, identify the shortages in the use of N:P stoichiometry theory, and put forward some perspectives for future research to be conducted.展开更多
Multispecies ecological models have been used for predicting the effects of fishing activity and evaluating the performance of management strategies. Size-spectrum models are one type of physiologically-structured eco...Multispecies ecological models have been used for predicting the effects of fishing activity and evaluating the performance of management strategies. Size-spectrum models are one type of physiologically-structured ecological model that provide a feasible approach to describing fish communities in terms of individual dietary variation and ontogenetic niche shift. Despite the potential of ecological models in improving our understanding of ecosystems, their application is usually limited for data-poor fisheries. As a first step in implementing ecosystem-based fisheries management（EBFM）, this study built a size-spectrum model for the fish community in the Haizhou Bay, China. We describe data collection procedures and model parameterization to facilitate the implementation of such size-spectrum models for future studies of data-poor ecosystems. The effects of fishing on the ecosystem were exemplified with a range of fishing effort and were monitored with a set of ecological indicators. Total community biomass, biodiversity index, W-statistic, LFI（Large fish index）, Mean W（mean body weight） and Slope（slope of community size spectra） showed a strong non-linear pattern in response to fishing pressure, and largest fishing effort did not generate the most drastic responses in certain scenarios. We emphasize the value and feasibility of developing size-spectrum models to capture ecological dynamics and suggest limitations as well as potential for model improvement. This study aims to promote a wide use of this type of model in support of EBFM.展开更多
This article reviews biological invasions in which predation （or its absence） plays a major role in the success of the invader. Examples are described in which the invader out-competes native species for the same fo...This article reviews biological invasions in which predation （or its absence） plays a major role in the success of the invader. Examples are described in which the invader out-competes native species for the same food, and cases in which the in-vader consumes valued native species. In many instances, better predator avoidance by the invasive species or the absence of predators in the new habitat contributes to the success of the invaders; in other cases native or introduced predators appear to be able to keep the invasive species in check. A relatively new management approach in the US is the idea of adding another trophic level - to have humans act as the predators and consume the invasive species. This approach is being utilized in Florida and throughout the Caribbean against the lionfish, but could be extended to other fishes, as well as to various invasive crustaceans and mollusks. This idea is controversial, and current regulations prohibiting the possession of individuals of the invasive species （e.g., mitten crabs or snakefish） would preclude the development of a fishery for them [Current Zoology 57 （5）： 613~524, 2011].展开更多
Circuits in barrels of the rodent brain’s primary somatosensory (S1) cortex build up following constructivist rules. Previous evidence in mice supports that the precise addition of barrel neuropil is promoted by insu...Circuits in barrels of the rodent brain’s primary somatosensory (S1) cortex build up following constructivist rules. Previous evidence in mice supports that the precise addition of barrel neuropil is promoted by insulin-like growth factor-1 (IGF-1). The signaling cascades mediating this response remain undetermined. To address whether the effects of IGF-1 upon the growth of S1 circuits are mediated by insulin receptor substrate-1 (IRS-1), we studied barrel size in adult mice having the IRS-1 gene knocked out (IRS-1 ko). Our results reveal that barrel size is similar between wild type and IRS-1 ko mice suggesting that IRS-1 is not essential for barrel circuitry growth. Hence, investigations aimed at exploring other substrates activated by IGF-1, namely IRS-2 and IRS-4, are needed to reveal signaling pathways that mediate the precise addition of S1 neuronal circuitry.展开更多
Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we ...Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we investigated wheat(Triticum aestivum L.)rhizosphere protistan communities under naturally occurring salinity(NOS)and irrigation-reduced salinity(IRS),and linked a plant salinity stress index(PSSI)to different protistan groups in a nontidal coastal saline soil.We found that the PSSI was significantly correlated with rhizosphere cercozoan communities(including bacterivores,eukaryvores,and omnivores)and that these communities were important predictors of the PSSI.Structural equation modeling suggested that root exudation-induced change in bacterial community composition affected the communities of bacterivorous and omnivorous Cercozoa,which were significantly associated with the PSSI across wheat cultivars.Network analysis indicated more complex connections between rhizosphere bacteria and their protistan predators under IRS than under NOS,implying that alleviation of salinity stress promotes the predation of specific cercozoans on bacteria in rhizospheres.Moreover,the Cercomonas directa inoculation was conducive to alleviation of salinity stress.Taken together,these results suggest that the physiological response of wheat plants to salinity stress is closely linked to rhizosphere Cercozoa through trophic regulation within the rhizosphere microbiome.展开更多
Carbon dioxide （CO2） is the main anthropogenic gas which has drastically increased since the industrial revolution, and current concentrations are projected to double by the end of this century. As a consequence, el...Carbon dioxide （CO2） is the main anthropogenic gas which has drastically increased since the industrial revolution, and current concentrations are projected to double by the end of this century. As a consequence, elevated CO2 is expected to alter the earths＇ climate, increase global temperatures and change weather patterns. This is likely to have both direct and indirect impacts on plants, insect pests, plant pathogens and their distribution, and is therefore problematic for the security of future food production. This review summarizes the latest findings and highlights current knowledge gaps regarding the influence of climate change on insect, plant and pathogen interactions with an emphasis on agriculture and food production. Direct effects of climate change, including increased CO2 concentration, temperature, patterns of rainfall and severe weather events that impact insects （namely vectors of plant pathogens） are discussed. Elevated CO2 and temperature, together with plant pathogen infection, can considerably change plant biochemistry and therefore plant defense responses. This can have substantial consequences on insect fecun- dity, feeding rates, survival, population size, and dispersal. Generally, changes in host plant quality due to elevated CO2 （e.g., carbon to nitrogen ratios in C3 plants） negatively affect insect pests. However, compensatory feeding, increased population size and distribution have also been reported for some agricultural insect pests. This underlines the importance of additional research on more targeted, individual insect-plant scenarios at specific locations to fully understand the impact of a changing climate on insect-plant-pathogen interactions.展开更多
The core ecosystem functioning(e.g.trophic transfer efficiency)is at risk of being disrupted by the growing mismatch between nutrient content of primary producers and nutrient demand of grazing consumers.Ecological st...The core ecosystem functioning(e.g.trophic transfer efficiency)is at risk of being disrupted by the growing mismatch between nutrient content of primary producers and nutrient demand of grazing consumers.Ecological stoichiometry provides a conceptual framework that explains this trophic interaction using C,N and P elemental composition across trophic levels.In light of ongoing climate change and eutrophication,previous studies have raised concerns regarding the growing stoichiometric mismatch between phytoplankton and zooplankton,given the stoichiometric plasticity of phytoplankton.However,there is currently little conclusive evidence on the stoichiometric mismatch from a dual perspective of phytoplankton and zooplankton.To address this,we conducted a mesocosm experiment to investigate the separate and combined effects of climate warming(a constant increase of t3.5C plus heat waves)and eutrophication(nutrient addition)on stoichiometric mismatch between phytoplankton and zooplankton by examining stoichiometric changes in both communities.We observed a growing trend in stoichiometric mismatches when warming or nutrient addition acted individually,which was mediated by the increase in nutrient demand(N,P elements)of zooplankton growth.However,when these stressors acted jointly,the mismatches were reversed.This could be because climate warming and eutrophication combined would lead to changes in species composition,which accordingly reshaped the stoichiometric composition at the community level.These results illustrate the need of stoichiometric mismatches for understanding the implication of global change on trophic interactions and ecosystem functioning,requiring consideration not only of cross-trophic levels but also of compositional changes within communities.展开更多
Biochar applications have an enormous impact on the soil microbial community and functionality.However,the majority of the knowledge on biochar-microbe interaction derives almost exclusively from bacterial and fungal ...Biochar applications have an enormous impact on the soil microbial community and functionality.However,the majority of the knowledge on biochar-microbe interaction derives almost exclusively from bacterial and fungal studies,while the vast majority of eukaryotic diversity,protists,are mostly neglected.Protists play important roles in the soil ecosystem as microbial predators,decomposers,photoautotrophs,pathogens,and parasites and they are essential for a healthy soil ecosystem.Toward a comprehensive understanding of the effects of biochar application,we need more studies on protists across the full breadth of eukaryotic diversity.The aim of this article is to highlight the research needs and discuss potential research ideas on biochar-protist interaction,which would advance our knowledge of biochar-microbe interaction.展开更多
Benthic macroinvertebrates play key roles in shallow aquatic ecosystems and can contribute substantially to aquatic food webs.However,how macroinvertebrates with different behaviors(for example,pertaining to locomotio...Benthic macroinvertebrates play key roles in shallow aquatic ecosystems and can contribute substantially to aquatic food webs.However,how macroinvertebrates with different behaviors(for example,pertaining to locomotion,foraging and burrowing)impact water quality and primary producers has not been fully explored.Here,we performed two consecutive microcosm experiments to test the effects of(1)macroinvertebrates with different behaviors(a low mobility scraper aquatic snail Bellamya aeruginosa and a high mobility shredder freshwater shrimp Macrobrachium nipponense)and(2)different shrimp biomasses on water clarity and the composition of benthic primary producers.The results showed that presence of snails significantly increased the biomass of filamentous green algae and decreased the biomass of periphyton.In contrast,presence of shrimp significantly decreased the biomass of filamentous green algae and increased the biomass of periphyton,and these effects were biomass dependent.Filamentous green algae disappeared when shrimp biomass reached 9.8 g m^(-2).No interactive effects of snail and shrimp presence were found.This could be attributed to different food preferences by the two consumers,with snails preferring periphyton(mainly diatoms)and shrimp preferring filamentous green algae.The presence of snails decreased water turbidity,while shrimp increased water turbidity,which showed a hump-shaped response to shrimp biomass with a peak at 24.2 g m^(-2).These results are likely because the snail is a low mobility grazer and can filter suspended particles,while the shrimp is a high mobility shredder with burrows,which can strongly disturb sediment.The decrease in water disturbance at high shrimp biomass might be due to food limitation,thus reducing burrowing and foraging activities.Neither snail nor shrimp affected the biomass of H.verticillata,while the biomass of V.spinulosa increased with shrimp biomass.The reason for this could be that shrimp increased nutrient availability and decreased the growth of filamentous green algae that compete with macrophytes.Our study demonstrated that different macroinvertebrates have complementary functions in benthic habitats;thus,maintaining macroinvertebrate diversity is important for shallow aquatic ecosystems.Furthermore,the freshwater shrimp M.nipponense could be a potential consumer to control filamentous green algal blooms in its native range,but their biomass should be taken into consideration.展开更多
Bacillus thuringiensis var. israelensis （Bti） is the most commonly used larvicide to control mosquitoes worldwide. Considered as nontoxic to most organisms, Bti can nevertheless cause trophic perturbations to natura...Bacillus thuringiensis var. israelensis （Bti） is the most commonly used larvicide to control mosquitoes worldwide. Considered as nontoxic to most organisms, Bti can nevertheless cause trophic perturbations to natural communities by reducing the abundance of Chironomidae, which are a key element of wetland food webs. Since August 2006, up to 8400 of the 33 000 ha of mosquito larval biotopes in the Camargue （Rh6ne delta, in southern France）, are monitored by a public agency and Bti-sprayed （aqueous solution of VectoBac 12AS at 2.5 L/ha） whenever mosquito larvae （Ochlerotatus easpius and Oc. detritus） appeared in water bodies. This resulted in 30-50 aerial treatments/year, in addition to ground spraying of unknown frequency. The sprayed habitats include Phragmites australis reedbeds, which support a specific avifauna of conservation concern. We compared the abundance of invertebrate prey available to passerine birds at treated and control sites relative to the predicted values based on hydrology over a 9-year period. Food available to reed passerines was significantly reduced at treated areas, translating into a 34% decrease in breeding birds based on predictive modeling. The most affected arthropods were Diptera, Aranaea, Coleoptera, and Hymenoptera. No cumulative effects were observed over time, but the recovery of the invertebrate assemblage after the cessation of mosquito control was delayed due to Bti spore persistence and proliferation in the sediments. While hydrology remains a prime factor influencing primary and secondary productivity of the Camargue reed marshes, Bti spraying had significant negative effects on animal communities at several trophic levels.展开更多
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest (No. 200903005)the National Basic Research Program of China (973 Program) (Nos. 2011CB409805, 2010CB951204)+3 种基金the National Natural Science Foundation of China (No. 40976103)the Special Fund for the Basic R&D Program in the Central Non-profit Research Institutes (No. 2009-ts-10)the Taishan Scholar Program of Shandong Provincethe Yellow & Bohai Seas Scientific Observation and Experiment Station for Fishery Resources and Environment, Ministry of Agriculture
文摘The southem Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. Atrophic mass-balance model of the southern Yellow Sea during 2000-2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to 〉V was 5.0%, 5.7%, 18.5%, and 19.7%-20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum＇s ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.
基金The authors would like to thank Angels Tudo for technical assistance during the field collection of the.samples and laboratory procedures.We would like also to acknowledge the owners of the analyzed crop plot for allowing us access to their fields.This research was funded by the Spanish Ministry of Economy,Industry and Competitiveness(grant AGL2014-53970-C2-2-R)by the CERCA Program(Centres de Recerca de C atalunya)of the Generalitat de Catalunya.Ivan Batuecas received.funding from the grant BES-2015-075700 from the Span-ish Mimistry of Science,Innovation and Universities.
文摘To understand trophic interactions and the precise ecological role of each predatory species,it is important to know which arthropod and plant resources are used by generalist predators in agroecosystems.Molecular approaches,such as the use of high-throughput sequencing(HTS),play a key role in identifying these resources.This study develops a multiprimer metabarcoding approach for screening the most common trophic interactions of two predatory arthropods with contrasting morphologies,Rhagonycha fulva(Coleoptera:Cantharidae)and Anthocoris nemoralis(Hemiptera:Anthocoridae)collected from a peach crop.To reduce the time and cost of this metabarcoding approach,we first evaluated the effect of using two different predator-pools of different size(10 and 23 individuals of the same species).We also used our system to analyze the performance of one and two primer pairs in the same library.Our results show that the analysis of 23 individuals together with the use of two primer pairs in the same library optimize the HTS analysis.Using these best-performing conditions,we then analyzed the entire bodies of field-collected predators as well as the washing solutions used to clean the insect bodies.We were able to identify both gut content(i.e.,diet)and external pollen load(i.e.,on the insects’bodies).This study also demonstrates the importance of washing predatory insects’bodies prior to HTS analysis when the target species have a considerable size(>10 mm)and hairy structures.This metabarcoding approach has significant potential for the study of trophic links in agriculture,revealing expected and unexpected trophic relationships.
文摘Dear Editor,Life-history studies including dietary preferences and trophic interactions are essential for understanding community ecology in lizards(Pianka,1986).The family Agamidae is one of the largest in terms of species diversity and occurs in a variety of habitats(Uetz et al.,2024).
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA28110100 and XDA28020202)the National Key Research and Development Program of China(No.2022YFD1500203)+3 种基金the National Natural Science Foundation of China(No.42177332)the China Agriculture Research System(Nos.CARS-03 and CARS-52)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2023325)the Anhui Provincial Key Research and Development Project,China(No.2023n06020056).
文摘Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.However,their effects are poor because of the complex water and temperature conditions,especially under sodic conditions.Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM,providing a new direction for promoting high-efficiency straw conversion into SOM.In this study,we conducted a^(13)C-labeled straw degradation experiment using small molecules derived from lignin(LSMs)and humus(HSMs)as activators,investigating their effects on the microbial communities and formation of newly formed mineral-associated(^(13)C-MAOM)and particulate(^(13)C-POM)organic matter from^(13)C-labeled straw in both sodic and non-sodic soils.The^(13)C-labeled straw was mainly converted into^(13)C-MAOM,accounting for 73.97%–92.67%of the newly formed SOM.Biopolymer-derived small molecules decreased the exchangeable sodium percentage(ESP),but increased contents of^(13)C-MAOM and^(13)C-POM by shifting microbial communities,strengthening microbial cross-trophic interactions,enhancing enzyme activities,and increasing microbial residues in both soils.Addition of HSMs had greater impacts on^(13)C-MAOM formation than LSM addition.The^(13)C-MAOM and^(13)C-POM formation negatively correlated with ESP,but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils.Our results suggest that biopolymer-derived small molecules promote^(13)C-MAOM and^(13)C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers.Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions.
文摘A mass-balanced Ecopath model presents a quantitative description of the trophic structure,fl ow of energy and trophic interaction among ecological groups of an ecosystem.The Ecopath with Ecosim(EwE)modeling program(Version 6.5)was used to develop a preliminary trophic model for a tropical freshwater reservoir.The total fi sh biomass was 6.245 t/km 2 and the highest trophic level of the reservoir was 3.362(for snakehead).The ecosystem is phytoplankton based because primary producers originated 68%and detritus originated 32%of the total fl ow from lower trophic level.The gross effi ciency of the fi shery was 0.004,suggesting the ineffi ciency of the system.The positive eff ect of phytoplankton and detritus on most of the other groups were evident from mixed trophic analysis while moderately higher ecotrophic effi ciency(EE)of phytoplankton shows the ecosystem’s potential bottom-up control.The competition for the same resources among diff erent groups was also obvious.The ratio of primary production/respiration(1.969)suggests that the ecosystem is at the developing stage and utmost contemplation should be given to concerned human activities.The low value of relative ascendancy(30.13)and overhead(69.87)reveals the stability of the ecosystem and some degrees of maturity.It also predicts the presence of signifi cant strength in reserve of the system to withstand or overcome any perturbation.However,ecologically sustainable resource management plans should be implemented to ensure the sustainability of this reservoir resources.
文摘Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study ecology from genes to the biosphere. Among this trend, N:P stoichiometry is used actively in ecological interactions since nitrogen (N) and phosphorus (P) are the two most important elements in most ecosystems. This article reviews the application of N:P stoichiometry to the studies of ecological problems at different levels, including ecosystem, community and species. Meanwhile, we also provide the cellular basis of N:P stoichiometry, identify the shortages in the use of N:P stoichiometry theory, and put forward some perspectives for future research to be conducted.
基金The Special Fund for Agriscientific Research in the Public Interest under contract No.201303050the Fundamental Research Funds for the Central Universities under contract Nos 201022001 and 201262004
文摘Multispecies ecological models have been used for predicting the effects of fishing activity and evaluating the performance of management strategies. Size-spectrum models are one type of physiologically-structured ecological model that provide a feasible approach to describing fish communities in terms of individual dietary variation and ontogenetic niche shift. Despite the potential of ecological models in improving our understanding of ecosystems, their application is usually limited for data-poor fisheries. As a first step in implementing ecosystem-based fisheries management（EBFM）, this study built a size-spectrum model for the fish community in the Haizhou Bay, China. We describe data collection procedures and model parameterization to facilitate the implementation of such size-spectrum models for future studies of data-poor ecosystems. The effects of fishing on the ecosystem were exemplified with a range of fishing effort and were monitored with a set of ecological indicators. Total community biomass, biodiversity index, W-statistic, LFI（Large fish index）, Mean W（mean body weight） and Slope（slope of community size spectra） showed a strong non-linear pattern in response to fishing pressure, and largest fishing effort did not generate the most drastic responses in certain scenarios. We emphasize the value and feasibility of developing size-spectrum models to capture ecological dynamics and suggest limitations as well as potential for model improvement. This study aims to promote a wide use of this type of model in support of EBFM.
文摘This article reviews biological invasions in which predation （or its absence） plays a major role in the success of the invader. Examples are described in which the invader out-competes native species for the same food, and cases in which the in-vader consumes valued native species. In many instances, better predator avoidance by the invasive species or the absence of predators in the new habitat contributes to the success of the invaders; in other cases native or introduced predators appear to be able to keep the invasive species in check. A relatively new management approach in the US is the idea of adding another trophic level - to have humans act as the predators and consume the invasive species. This approach is being utilized in Florida and throughout the Caribbean against the lionfish, but could be extended to other fishes, as well as to various invasive crustaceans and mollusks. This idea is controversial, and current regulations prohibiting the possession of individuals of the invasive species （e.g., mitten crabs or snakefish） would preclude the development of a fishery for them [Current Zoology 57 （5）： 613~524, 2011].
基金supported in part by CONACyT(Grant No.82879 to G.G.O.)PAPIIT-UNAM(Grants Nos.IN203912-3 to G.G.O.and IA202013-2 to E.U.Q.)CIC-UMSNH(Grant No.8.37 to A.L.F.F.).
文摘Circuits in barrels of the rodent brain’s primary somatosensory (S1) cortex build up following constructivist rules. Previous evidence in mice supports that the precise addition of barrel neuropil is promoted by insulin-like growth factor-1 (IGF-1). The signaling cascades mediating this response remain undetermined. To address whether the effects of IGF-1 upon the growth of S1 circuits are mediated by insulin receptor substrate-1 (IRS-1), we studied barrel size in adult mice having the IRS-1 gene knocked out (IRS-1 ko). Our results reveal that barrel size is similar between wild type and IRS-1 ko mice suggesting that IRS-1 is not essential for barrel circuitry growth. Hence, investigations aimed at exploring other substrates activated by IGF-1, namely IRS-2 and IRS-4, are needed to reveal signaling pathways that mediate the precise addition of S1 neuronal circuitry.
基金financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA24020104,XDA28110100,XDA28020203)the National Key R&D Program of China(Grant Nos.2022YFD1500203,2022YFD1500401)+2 种基金the China Agriculture Research System(Grant Nos.CARS-03,CARS-52)the National Natural Science Foundation of China(Grant No.42177332)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023325).
文摘Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we investigated wheat(Triticum aestivum L.)rhizosphere protistan communities under naturally occurring salinity(NOS)and irrigation-reduced salinity(IRS),and linked a plant salinity stress index(PSSI)to different protistan groups in a nontidal coastal saline soil.We found that the PSSI was significantly correlated with rhizosphere cercozoan communities(including bacterivores,eukaryvores,and omnivores)and that these communities were important predictors of the PSSI.Structural equation modeling suggested that root exudation-induced change in bacterial community composition affected the communities of bacterivorous and omnivorous Cercozoa,which were significantly associated with the PSSI across wheat cultivars.Network analysis indicated more complex connections between rhizosphere bacteria and their protistan predators under IRS than under NOS,implying that alleviation of salinity stress promotes the predation of specific cercozoans on bacteria in rhizospheres.Moreover,the Cercomonas directa inoculation was conducive to alleviation of salinity stress.Taken together,these results suggest that the physiological response of wheat plants to salinity stress is closely linked to rhizosphere Cercozoa through trophic regulation within the rhizosphere microbiome.
文摘Carbon dioxide （CO2） is the main anthropogenic gas which has drastically increased since the industrial revolution, and current concentrations are projected to double by the end of this century. As a consequence, elevated CO2 is expected to alter the earths＇ climate, increase global temperatures and change weather patterns. This is likely to have both direct and indirect impacts on plants, insect pests, plant pathogens and their distribution, and is therefore problematic for the security of future food production. This review summarizes the latest findings and highlights current knowledge gaps regarding the influence of climate change on insect, plant and pathogen interactions with an emphasis on agriculture and food production. Direct effects of climate change, including increased CO2 concentration, temperature, patterns of rainfall and severe weather events that impact insects （namely vectors of plant pathogens） are discussed. Elevated CO2 and temperature, together with plant pathogen infection, can considerably change plant biochemistry and therefore plant defense responses. This can have substantial consequences on insect fecun- dity, feeding rates, survival, population size, and dispersal. Generally, changes in host plant quality due to elevated CO2 （e.g., carbon to nitrogen ratios in C3 plants） negatively affect insect pests. However, compensatory feeding, increased population size and distribution have also been reported for some agricultural insect pests. This underlines the importance of additional research on more targeted, individual insect-plant scenarios at specific locations to fully understand the impact of a changing climate on insect-plant-pathogen interactions.
基金supported by the National Natural Science Foundation of China[grant numbers 32171515,31800389]the Hundred-Talent Program of the Chinese Academy of Sciencesthe International Cooperation Project of the Chinese Academy of Sciences[grant numbers 152342KYSB20190025].
文摘The core ecosystem functioning(e.g.trophic transfer efficiency)is at risk of being disrupted by the growing mismatch between nutrient content of primary producers and nutrient demand of grazing consumers.Ecological stoichiometry provides a conceptual framework that explains this trophic interaction using C,N and P elemental composition across trophic levels.In light of ongoing climate change and eutrophication,previous studies have raised concerns regarding the growing stoichiometric mismatch between phytoplankton and zooplankton,given the stoichiometric plasticity of phytoplankton.However,there is currently little conclusive evidence on the stoichiometric mismatch from a dual perspective of phytoplankton and zooplankton.To address this,we conducted a mesocosm experiment to investigate the separate and combined effects of climate warming(a constant increase of t3.5C plus heat waves)and eutrophication(nutrient addition)on stoichiometric mismatch between phytoplankton and zooplankton by examining stoichiometric changes in both communities.We observed a growing trend in stoichiometric mismatches when warming or nutrient addition acted individually,which was mediated by the increase in nutrient demand(N,P elements)of zooplankton growth.However,when these stressors acted jointly,the mismatches were reversed.This could be because climate warming and eutrophication combined would lead to changes in species composition,which accordingly reshaped the stoichiometric composition at the community level.These results illustrate the need of stoichiometric mismatches for understanding the implication of global change on trophic interactions and ecosystem functioning,requiring consideration not only of cross-trophic levels but also of compositional changes within communities.
基金the Japan Society for the Promotion of Science(JSPS)to Asiloglu R(Grant No.JP22K14804).
文摘Biochar applications have an enormous impact on the soil microbial community and functionality.However,the majority of the knowledge on biochar-microbe interaction derives almost exclusively from bacterial and fungal studies,while the vast majority of eukaryotic diversity,protists,are mostly neglected.Protists play important roles in the soil ecosystem as microbial predators,decomposers,photoautotrophs,pathogens,and parasites and they are essential for a healthy soil ecosystem.Toward a comprehensive understanding of the effects of biochar application,we need more studies on protists across the full breadth of eukaryotic diversity.The aim of this article is to highlight the research needs and discuss potential research ideas on biochar-protist interaction,which would advance our knowledge of biochar-microbe interaction.
基金supported by the National Natural Science Foundations of China(Grant No.32001158 and Grant No.31872687)China Postdoctoral Science Foundation(Grant No.2019M652734)the Research funds of The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control(No.2001K003).
文摘Benthic macroinvertebrates play key roles in shallow aquatic ecosystems and can contribute substantially to aquatic food webs.However,how macroinvertebrates with different behaviors(for example,pertaining to locomotion,foraging and burrowing)impact water quality and primary producers has not been fully explored.Here,we performed two consecutive microcosm experiments to test the effects of(1)macroinvertebrates with different behaviors(a low mobility scraper aquatic snail Bellamya aeruginosa and a high mobility shredder freshwater shrimp Macrobrachium nipponense)and(2)different shrimp biomasses on water clarity and the composition of benthic primary producers.The results showed that presence of snails significantly increased the biomass of filamentous green algae and decreased the biomass of periphyton.In contrast,presence of shrimp significantly decreased the biomass of filamentous green algae and increased the biomass of periphyton,and these effects were biomass dependent.Filamentous green algae disappeared when shrimp biomass reached 9.8 g m^(-2).No interactive effects of snail and shrimp presence were found.This could be attributed to different food preferences by the two consumers,with snails preferring periphyton(mainly diatoms)and shrimp preferring filamentous green algae.The presence of snails decreased water turbidity,while shrimp increased water turbidity,which showed a hump-shaped response to shrimp biomass with a peak at 24.2 g m^(-2).These results are likely because the snail is a low mobility grazer and can filter suspended particles,while the shrimp is a high mobility shredder with burrows,which can strongly disturb sediment.The decrease in water disturbance at high shrimp biomass might be due to food limitation,thus reducing burrowing and foraging activities.Neither snail nor shrimp affected the biomass of H.verticillata,while the biomass of V.spinulosa increased with shrimp biomass.The reason for this could be that shrimp increased nutrient availability and decreased the growth of filamentous green algae that compete with macrophytes.Our study demonstrated that different macroinvertebrates have complementary functions in benthic habitats;thus,maintaining macroinvertebrate diversity is important for shallow aquatic ecosystems.Furthermore,the freshwater shrimp M.nipponense could be a potential consumer to control filamentous green algal blooms in its native range,but their biomass should be taken into consideration.
文摘Bacillus thuringiensis var. israelensis （Bti） is the most commonly used larvicide to control mosquitoes worldwide. Considered as nontoxic to most organisms, Bti can nevertheless cause trophic perturbations to natural communities by reducing the abundance of Chironomidae, which are a key element of wetland food webs. Since August 2006, up to 8400 of the 33 000 ha of mosquito larval biotopes in the Camargue （Rh6ne delta, in southern France）, are monitored by a public agency and Bti-sprayed （aqueous solution of VectoBac 12AS at 2.5 L/ha） whenever mosquito larvae （Ochlerotatus easpius and Oc. detritus） appeared in water bodies. This resulted in 30-50 aerial treatments/year, in addition to ground spraying of unknown frequency. The sprayed habitats include Phragmites australis reedbeds, which support a specific avifauna of conservation concern. We compared the abundance of invertebrate prey available to passerine birds at treated and control sites relative to the predicted values based on hydrology over a 9-year period. Food available to reed passerines was significantly reduced at treated areas, translating into a 34% decrease in breeding birds based on predictive modeling. The most affected arthropods were Diptera, Aranaea, Coleoptera, and Hymenoptera. No cumulative effects were observed over time, but the recovery of the invertebrate assemblage after the cessation of mosquito control was delayed due to Bti spore persistence and proliferation in the sediments. While hydrology remains a prime factor influencing primary and secondary productivity of the Camargue reed marshes, Bti spraying had significant negative effects on animal communities at several trophic levels.
