Measurement of Digital Economy Development Level in Yangtze River Delta and Its Influence on Ecological Efficiency

Based on the panel data of 41 cities in the Yangtze River Delta from 2007 to 2018,this paper empirically tests the impact of digital economy development on urban ecological efficiency in the Yangtze River Delta.The results show that the development level of digital economy in Yangtze River Delta urban agglomeration is fluctuating and rising;the development of digital economy has a significant positive role in promoting the improvement of urban ecological efficiency;there is significant regional heterogeneity in the promotion of ecological efficiency by digital economy,especially in central cities.

Did Ecological Engineering Projects Have a Significant Effect on Large-scale Vegetation Restoration in Beijing-Tianjin Sand Source Region, China？ A Remote Sensing Approach

Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.

In situ determination on food consumption and ecological conversion efficiency of a marine fish species, Hyporhamphus sajori

The food consumption and ecological conversion efficiency of a species marine pelagic andsmall size fish, Hyporhamphus sajori, were determined by using in situ stomach content method presented by Eggers. The results showed that: (1) the fish was taken in food all day, so empty-stomach rate was very low, taking up about 4.5% of the total determined fish number. However, the fish still has significant daily feeding rhythm. A feeding peak was found 0:00 o'clock at night, but feeding level was always high in the daytime; (2) relationship between instantaneous food content in stomach and corresponding time could be described as S_t = a · e (-b·t). There was not significant difference of instantaneous gastric evacuation rate between two determinations, with average value being 0.13 × 10^(-2) g/ (g' h) (wet weight); (3) the daily food consumption tended to change in irregular waving form, with average value being (10.16Xl0^(-2)±1.19xl0(-2) g/ (g·d) (wet weight) or (55.56 × 10(-2) ±6.51 × 10^(-2) kJ/ (g·d). The wave distance is constant and about 14 d, but the wave height changed largely; (4) actual determining value of daily growth rate was 3.24 × 10^(-2)g/ (g·d) (wet weight) or 12.91 × 10^(-2)kJ/ (g·d), from which 31.89% (wet weight) or 23.24% kJ of ecological conversion efficiency could be obtained.

Application of ecological footprint in ecological industrial systems:a study case of maize-MSG production systems

To improve the comparability of the research results of ecological industry, the ecological footprint is appliedto analyze the resource utilization and environmental pollution in various subsystems, taking maize-MSG as a case.Results show that the production process from maize to MSG is a extended process of ecological footprint, and that theecological footprint of the maize production is the biggest; the extension of ecological footprint is followed by the increaseof footprint profit, which means that the extension of production chain is an important method to improve the resourcesprofit; the systems have a big proportion of the indirect energy ecological footprint; the air and water pollution in MSGsubsystem is the most serious. At last, it can be identified that ecological footprint is a good method to measure resourceutilization and environmental pollution in various subsystems of an integrated ecological industry.

Vertical and temporal distribution of nitrogen and phosphorus and relationship with their influencing factors in aquatic-terrestrial ecotone:a case study in Taihu Lake,China

Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone （ATE） of Taihu Lake were investigated, and the relations among N, P, ORP （oxidation reduction potential）, TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3^--N, DON （dissolved organic nitrogen） and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4^＋-N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3^--N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3^--N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation ofTN, TP, NO3^--N, NH4^＋-N and DON is significant, of which the variation coefficient of NO3^--N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.

County urbanization,agricultural servitization,and agricultural eco-efficiency:Statistical verification based on Chongqing

Agricultural ecologicalization is an important starting point to promote sustainable and high-quality development of agriculture.Based on the panel data of 37 districts(counties)in Chongqing from 2004 to 2019,the DDF-GML index method is used to measure the agricultural ecological efficiency of Chongqing.Based on the analysis of the interaction mechanism of urbanization,agricultural service,and agricultural ecological efficiency,with the help of the PVAR model verifies the relationship between the three.The study found that urbanization,agricultural service,and agricultural ecological efficiency have significant inertia effects and path dependence,especially agricultural ecological efficiency can provide more than 90%of its variance contribution,while urbanization and agricultural ecological efficiency have a significant impact on agricultural ecological efficiency.The influence will become weaker and weaker over time,obeying the law of diminishing margins.Therefore,to promote the development of agricultural ecologicalization,we must rely on the clean,green,and ecological development of agricultural production itself.At the same time,we also need to further improve the urbanization and agricultural service modernization system to maximize the benefits of agriculture.

Developing an integrated urban ecological efficiency framework for spatial ecological planning:A case on a tropical mega metropolitan area of the global south

Rapid urbanization has emerged as one of the most critical challenges to ecological sustainability in urban areas.In developing countries,the degradation of the ecosystem is more prominent due to the lack of urban planning.Thus,it has become urgent for researchers to identify the ecological efficiency(EE)changes imposed by urban expansion and promote sustainable land use planning.This study aims to develop a comprehensive urban ecological efficiency(UEE)framework in the Kolkata Metropolitan Area(KMA),India,from 2000 to 2020.Principal component analysis(PCA)was used to develop a remote sensing-based UEE index(UEEI)based on five effective ecological parameters(Greenness,Dryness,Heat,Wetness and vegetation health.A single sensitivity parameter was also calculated to determine the role of a single parameter based on which management strategies can be carried out.The findings showed that(i)there were substantial deteriorations of UEE in the last 20 years.In 2000 the areas with good EE were about 65.5%which declined to 53.72%in 2010 and 20.87%in 2020.The areas with good UEE decreased 68%and 61%from 2000 to 2020 and 2010 to 2020,respectively;(ii)the areas with good UEE were 52%in 2000,while 38%in 2010.Most urban centres(Bhadreshwar,Champdani,Srirampur,Bally,Howrah,Kamarhati,Baranagar,Dum Dum,South Dum Dum,Rajarhat,Bidhannagar)located around the Kolkata megacity are characterized by poor and very poor EE(ranges of 0.60-1.00).Thus,spatiotemporal pattern of UEE could assist to clarify the administrative responsibilities as well as obligations.In addition to this,the UEE framework can help for scientific guidance of urban ecosystem protection and restoration through comprehensive spatial landscape planning.

Contrastive Study of the Circular Economy of Coal Resource City Based on Ecological Efficiency and C Model

Being a developing country, the evaluation of Chinese circular economy should have its particular crite- rion that suits for specific national conditions. With the growth of economy, Chinese environmental loads should be permitted to increase at an appropriate speed. Based on this concept, this paper divides the process of evaluation into two parts which include evaluation of development level and evaluation of development performance. Firstly, this paper sets up a reference system which includes Zaozhuang City of Shandong Province, Jiaozuo City of Henan province, Shizuishan City of Ningxia Hui Autonomous Region and China that is regarded as a region respectively, analyzes the development level of circular economy of coal resource cities based on the evaluation indicator of ecological efficiency, and puts forward the future direction of circular economy of coal resource cities. Secondly, based on C Model of Circular Economy, this paper constructs the measurement model of development perform- ance in which study regions are analyzed in a particular period that is from 2000 to 2020, and evaluates the de- velopment performance of circular economy for study regions according to the relationship of growth multiples between economic scale and environmental loads. We can draw several main conclusions： firstly, the development pathways of all four study regions belong to type I[ which resource efficiency is preferred. Secondly, the com- prehensive energy consumption efficiencies of coal resource cities were left far behind by China＇s average level. Thirdly, the circular economies of all study regions have achieved remarkable progress. Fourthly, the development level of circular economy can be evaluated from two dimensions which consist of horizontal comparison method and vertical comparison method. Fifthly, C model is an appropriate development model that suits for Chinese na- tional conditions and could be selected as an important method to evaluate regional development performance of circular economy.

Thermodynamic performance of Dual-Miller cycle(DMC) with polytropic processes based on power output, thermal efficiency and ecological function

This study reports a new model of an air standard Dual-Miller cycle(DMC) with two polytropic processes and heat transfer loss.The two reversible adiabatic processes which could not be realized in practice are replaced with two polytropic processes in order to more accurately reflect the practical working performance. The heat transfer loss is taken into account. The expressions of power output, thermal efficiency, entropy generation rate(EGR) and ecological function are addressed using finite-time thermodynamic theory. Through numerical calculations, the influences of compression ratio, cut-off ratio and polytropic exponent on the performance are thermodynamically analyzed. The model can be simplified to other cycle models under specific conditions, which means the results have an certain universality and may be helpful in the design of practical heat engines. It is shown that the entropy generation minimization does not always lead to the best system performance.

Summarization on Evaluation of Ecological Value of Artificial Forest

This paper is a summarization on evaluation of value of artificial forest. The main contents include: (i) the difference in concepts between ecological function, ecological efficiency and ecological benefits of artificial forest; (ii) the motive and several taches of economic feedback or compensation for ecological benefit; (iii)the ecological efficiencies of artificial forest and the main correlative factors which includes the ecological efficiencies of artificial forest and the main correlation factors infecting the ecological efficiency; (iv) the basic math correlations between ecological efficiencies of artificial forest and the related factors; (v) service range of the ecological efficiencies of artificial forest; and (vi) the basic principle of measurement of ecological efficiencies of artificial forest. At the end, the basic methods of main ecological efficiencies of artificial forest are expatiated.

Spatio-temporal characteristics and typical patterns of eco-efficiency of cultivated land use in the Yangtze River Economic Belt, China

Identifying the dynamics of the eco-efficiency of cultivated land use(ECLU)is important to balance food security and environmental protection.The Yangtze River Economic Belt(YREB)is a vital region of national strategic development in China.However,the spatio-temporal characteristics and typical patterns of the ECLU in the YREB remain unclear.This study aims to reveal the spatio-temporal characteristics of the ECLU by using the super-efficiency slack-based measure(SBM)and a spatial autocorrelation model.The typical patterns of the ECLU were classified based on a decision tree algorithm.The results indicate that the overall ECLU increased from 0.78 to 0.87 from 2000 to 2019,dropping sharply in 2003 before rising again.Different reaches had similar trends.The local indicators of spatial association(LISA)cluster reflect that the spatial distributions of high-high and low-low agglomeration varied dramatically among these years.The ECLU was divided into three typical patterns considering the restriction of agrochemicals and water resources(RAW),cultivated land and agrochemicals(RCA),as well as technology(RT).Most cities belonged to the low ECLU category in RT pattern.Fully understanding the spatio-temporal characteristics and classification of the ECLU will provide a reference for decision-makers to improve the ECLU in different regions.

Energy budgets of the Chinese green lacewing （Neuroptera： Chrysopidae） and its potential for biological control of the cotton aphid （Homoptera： Aphididae）

Energy budgets of larval stages of the Chinese green lacewing, Chrysopa sinica （Tjeder） （Neuroptera： Chrysopidae） were determined under laboratory conditions at photoperiod of 14：10 L：D, 27 ± 1℃ and 75% ± 2% RH. The energy used as ingestion, assimilation, respiration, productivity and feces was constructed for each developmental stage. In addition, under these experimental conditions, the potential of C. sinica as a biological control agent was evaluated according to the ingestion by this predator and the energy content of cotton aphid, Aphis gossypii （Glover） （Homoptera： Aphididae）. The larval stage of C. sinica was able to consume 1281.4 1-day-old aphids, 1018.7 2-day-old aphids, 626.9 3-day-old aphids, 393.5 4-day-old aphids, 312.1 5-day-old aphids or 203.5 9-day-old aphids, respectively. No significant difference was detected between the estimated number of aphids consumed by the lacewings using energetic methods and the actual number of aphids consumed by the lacewings in this experiment. Our results showed that C. sinica is an important natural enemy of the cotton aphid, and energetic methods are very useful to quantify biological control efficacy of natural enemies.