Bibliometric analysis of Ecopath model in different ecosystem in China

ZHANG Wei,WU Huimin,WANG Jian,JIAO Jianhua,DAIYuanyuan,3＊

1.Tianjin Agricultural Development Service Center,Tianjin 300161,China;

2.Fisheries Research Institute of Tianjin,Tianjin 300221,China;

3.Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria of Nankai University,Tianjin 300350,China

Abstract:Ecopath model is an important evaluation model in the field of ecological research.At present,Ecopath model is mainly applied in the structure of food web,material circulation and energy flow,environmental capacity and so on.The Ecopath models in ocean,lake and reservoir ecosystems were reviewed,including the ecological nutrient conversion efficiency(EE),ecosystem characteristic index(CI),Niche Overlap and energy flow characteristics of trophic level.The practical significance of Ecopath model in marine ecosystem evaluation and application is expounded by comparing and analyzing the literature data,which provides the technical support for the scientific management of inland ecosystem in the future.

Keywords:Ecopath model,ecosystem,research progress

Ecopath with Ecosim(Ecopath)is a powerful ecosystem modelling software that has been validated in studies of different types of ecosystems in different latitudes around the world.Using Ecosystem ecology theory and modern computer technology,the Ecopath developed a mass-balanced model based on the food web and performed spatiotemporal dynamic simulations.The impacts of human activities on aquatic ecosystems are mainly manifested in two aspects:fishing and environmental pollution.The management and decision-making processes of aquatic ecosystems should not only take into account the impact of human activities on certain species,nor certain outputs,instead,it should be based on an in-depth understanding of the structure and function of ecosystems,as well as quantitative and integrated analysis.The traditional aquaculture mode mainly considers the maximum yield in the intensive pond,but the pollution of the water environment and the cost of production are only the secondary factors.With the continuous development of breeding technology,people begin to explore the high-efficiency ecological breeding mode and popularize it under the condition of intensive breeding.

The model has been widely used in ecosystem ecology and fisheries management studies.Research mainly focuses on the structure and function of ecosystems such as oceans,lakes and reservoirs,the flow of energy,the estimation of ecological capacity and the assessment of ecological effects.At present,only sea grass carp polyculture model,shrimp high-level ponds and other ecosystem structure and function,energy flow characteristics were studied.In the pond ecosystem,different ecological niche breeding species were constructed,and the multi-trophic level integrated breeding and breeding model was developed by making full use of the differences in food habits,water habitats,growth characteristics,etc.There are few reports on the ecology of material circulation and energy flow.This paper focuses on the research on the application of Ecopath model in the establishment of high-efficient ecological breeding model in pond ecosystem.It attempts to establish a comprehensive evaluation system of multi-trophic level integrated breeding in pond ecosystem,expecting to provide scientific reference for exploring the optimization scheme of the mixed culture mode of different breed.

1 Application research of Ecopath model

Ecopath model has been used to study the structure and function of marine ecosystem,such as ocean,lake,reservoir,pond,food web,energy flow and material cycle.As of April 7,2020,the research group carried out bibliometrics statistics based on CNKI database,entered the key word"Ecopath",and retrieved 541 articles,among which 54 articles were about the subject"Ecopath model",more than 40 articles on the application of marine ecosystems are revised Ecopath（Fig.1）.

Fig.1 Annual growth of papers included in CNKIdatabase

1.1 Study on Ecopath model in ocean,lake and reservoir Ecosystem

In China,the study of Ecopath model has increased rapidly in recent years,in marine ecosystems of Bohai Bay[1],Daya Bay[2],Artificial Reef Area[3],northern Continental Shelf of South China Sea[4],east China Sea[5],and the lake system of Great Lakes of Tai Lake[6],Chao Lake[7],Ge Lake[8],Wuli[9],Dianshan Lake[10]and Qiandao Lake[11].The model was used to study the trophic level,energy-material flow pathway,eco-nutritional transformation efficiency,and the characteristics of ecosystem development.Because of the difference in water environment,the Ecopath model's ecosystem characteristic parameter also has certain difference.

2 Document statistics

2.1 Keyword analysis

The key words in the literature can reflect the content,methods and objects of the research.From the distribution of high-frequency keywords,we can see the focus of the research.The keywords in 447 research papers were searched and the synonyms were manually cleared according to the meaning of the keywords.Primary producers,detritus,and aquatic food webs have higher frequency as keywords.When searching for words that are excluded,it is finally determined that the characterization of trophic level and aquatic food webs has the higher frequency of words.According to the ecosystem biomass,function group division,Ecopath model debugging and so on,it can be seen from Fig.2 that the common Ecopath model are mainly concentrated in the material circulation and the flow of energy.In addition,ecosystem structure,ecological role are also analyzed,and the subject words are classified by statistical methods.These search subject words can get visual analysis of the association between keywords.

Fig.2 The distribution of keywords

The dots in Fig.3 represent the topic of study.The connection between dots and their distances represents the degree of association between the contents of each other.The closer the line and the shorter the distance is,the higher the correlation between them.It can be seen from Fig.3 that there is a strong association between energy flow and trophic level,Ecopath model and trophic level between ecosystem structure and ecosystem,indicating that there is a large correlation between these research hotspots.

Fig.3 The association visualization graph of keywords

Fig.4 The distribution of subjects

2.2 Research field and periodical distribution

Based on the papers published in the main subject areas,field and periodical publications of the core statistical search in Chinese were carried out,and related statistical analysis was conducted.The publication of important source journals was collected and analyzed.The data show that the research papers involve multiple disciplines,with five of the most published being the fundamental science,and have received more attention in agricultural technology.

The authors selected 94 papers with high correlation to make a comprehensive analysis.Among them,66 papers on agricultural science and technology were published,accounting for 49.6%of the analysis papers;38 papers on fundamental science,accounting for 28.6%of the literature;and 26 papers on Engineering Science and Technology I,accounting for 19.5%.

2.3 Resource type distribution

A comprehensive analysis of the relevant literature shows that 57.4%of the articles mainly published in the form of periodicals,with a total of 54 articles published,followed by master's theses(19.1%)and 18 articles published,11 articles published in Chinese conferences(11.7%)and 8 doctoral theses(8.0%),and only 2 articles from international conferences,accounting for 2.1%.

2.4 Distribution of research institutions

It is clear from the statistical aspects of the institutions where the literature is published that,Shanghai Ocean University,the South China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Ocean University of China,the Yellow Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences,and Dalian Ocean University contributed to the publication.Among them,24 were published by Shanghai Ocean University,accounting for 17.8%,16 were published by the South China Sea Fisheries Research Institute,accounting for 11.9%,and 15 were published by Ocean University of China,as 11.1%.East China Normal University published 14,accounting for 10.4%;the Yellow Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences published 11,accounting for 8.1%;and other research institutions published 22,accounting for 16.3%.Marine science and technology research institutes are normally operated with marine field survey,marine environmental monitoring,marine biology identification and other resources,so their contribution rate in the literature published are the largest.

Fig.5 The distribution of subjects

Fig.6 The distribution of literature sources

2.5 The analysis of project fund sources

According to Fig.7 the source of fund is mainly the national science foundation.There are 21 articles from the National Natural Science Foundation,accounting 19.6%of the total number;the second is supported by State key basic research and development plan(Program 973),with 8.4%of the total number.National Science and Technology Support Program,Guangdong Natural Science Foundation contribution rate were 4.7%and 2.8%,respectively.There are,however,a number of important foundations that have funded work on this,and the proportion is as high as 57.0%.The fact that the Ecopath model is still in the development stage and some basic research is still in the exploratory stage may be the reason.Overall,the relevant research institutes along the eastern and southern coasts have done a lot of preliminary work in model application.

3 Expectation

Fig.7 The distribution of project fund sources

Bibliometric studies for a subject may be influenced by the type of database,the key words,the time of retrieval,and the tools of statistical analysis.

This article uses the literature metrology method for the analysis of Ecopath model related literature,to help with comprehensive understanding of the marine ecological environment researchers,marine fisheries producers,marine environmental monitoring departments and marine medicine research and development institutions.It is also expected to help production enterprises to understand and grasp the domestic Ecopath model research progress,especially its focus and problems to be solved,thus to strengthen academic exchanges,effective research cooperation,innovative ideas,and carry out new fields.

All the data are from the CNKI database,but because of the different retrieval conditions,may be different from the other two research results.Due to the author's knowledge level in the field of research,the analysis of the literature inevitably has omissions,and the analysis of the details is not perfect,which needs further study.

The present analysis are of uncertainty because of the following reasons:(1)retrieval style setting cannot fully include the target literature,different articles have multiple expressions of the same meaning,and words are diversified.(2)Domestic scientific research continuously updated literature database retrieval.The new literature and literature increased in a certain field keeps increasing day by day,and the study can only be locked in a specific time range.(3)The existence of error analysis,such as the different authors with the same name confusion or the same author mistakenly believes as different authors and other circumstances.

Acknowledgement

This paper is supported by the National large-scale freshwater fish industry technology system(CARS-45),Tianjin Freshwater Aquaculture Industry Technology System Innovation Team;Tianjin Science and Technology Program(16zzync00100),Tianjin Science and Technology Program(18ZXZYNC00150),and the Opening Foundation of Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria(2019-04).