Eastern Coastal Areas Of China Research Articles

Determining the carrying capacity and environmental risks of livestock and poultry breeding in coastal areas of eastern China: an empirical model.

The scale of regional livestock and poultry breeding (LPB) is generally not determined by the supporting capacity (fodder supply), but by the environmental carrying capacity of wastes from the LPB. The soil's own nutrient-supplying capacity used to be overlooked, which consequently produced an inaccurate result of carrying capacity estimation of the LPB. An empirical method was, therefore, employed to evaluate the soil's own nutrient-supplying capacity and further determine the carrying capacity and environmental risks of the LPB accurately. Thirteen counties along the coast of Jiangsu were selected to conduct this study, according to the framework of planting-breeding balance. Our results indicate that, including the soil's own nutrient-supplying capacity in the estimation of the carrying capacity of the LPB, it can reduce the original carrying capacity by 50%. This suggests that our empirical method can significantly increase the accuracy of estimating the carrying capacity of the LPB. The carrying capacity of the LPB in the study area varies from 1.5 to 48.08pigs/hm2, with a mean of 14pigs/hm2 based on phosphorus (P) balance. Furthermore, four sub-regions (Ganyu, Dongtai, Dafeng, and Guannan) that have a high P pollution risk should focus on controlling the scale of the LPB. The nitrogen (N) pollution risk in the study area is generally low. Results suggest that the soil's own nutrient-supplying capacity plays an important role in estimating the carrying capacity of the LPB accurately. This study can provide insights on reducing environmental risks of the LPB, which may be beneficial for decision makers.

Downstream oil supply security in China: Policy implications from quantifying the impact of oil import disruption

Unavoidable disruptions in the international oil supply create heavy pressures on the downstream oil market for oil-importing countries, especially China, whose high dependency on imported oil makes its downstream oil supply security an urgent issue. However, little attention has been paid to the supply security of the downstream oil industry with respect to dealing with import disruptions. Here, an integrated quantitative assessment framework is established to identify the impact of crude oil import disruptions on downstream oil supply security from the supply chain perspective. The dynamic scheduling process of the downstream oil supply chain under 72 import disruption scenarios is simulated by coupling a mathematical programming model with Latin hypercube sampling. The improved grey incidence evaluation method is applied for the comprehensive assessment of province-level and region-level oil product supply security based on the simulation results. The case of 31 provincial-level administrative regions in China in 2017 and 2020 is analysed as an example to demonstrate the framework. We find significant differences among provinces. The southwest and eastern coastal areas of China are vulnerable to potential oil supply disruptions, while the northwest China enjoys high supply security. Based on the results of this paper, policy implications are provided for the Chinese government. The design framework is not case-specific and can be applied for the quantitative assessment of other countries or regions.

Comparative genomic analysis and multi-drug resistance differences of Acinetobacter baumannii in Chongqing, China.

IntroductionMultidrug-resistance in Acinetobacter baumannii has emerged as a serious problem to public health. There is still a significant gap in the understanding of the multidrug-resistance and the genome diversity evolutionary process of A. baumannii in China, especially in the central and western regions.MethodsTen A. baumannii strains were collected from three hospitals in Chongqing, China. Whole-genome re-sequencing was used to obtain differences in genomic levels among strains. The diversity were determined by multi-locus sequence typing method, and investigate the genetic relationship between the ten strains and others by phylogenetic analysis. Comparative analysis focused on resistance genes related to insertions and deletions (InDels) and single-nucleotide polymorphisms (SNPs) was performed.ResultsThe overall G+C% content was 39.05%~39.43%, the average sequencing depth was 273.95~428.99, and the alignment ratio of the sequencing data was 92.93%~99.27%. A total of 42 InDels and 11,387 SNPs were detected in the coding sequence region of the isolates. Phylogenetic tree shows that the 10 A. baumannii isolates were divided into four relative groups, and there exist the possibility of cross-regional spread pattern. A total number of 19 drug resistance genes had been found in each strain, and efflux pump-related genes accounted for the most. Only AacA4 underwent a change in InDel. Six types of drug resistance genes were found in the SNPs resistance gene-related loci, among which gene ANT(3’’)-II and QacE mutations were found in each strain.ConclusionIn this study, the main mechanism of A. baumannii multi-drug resistance is due to the multi-drug efflux pump related genes. The point mutations at the SNPs sites of the six types of resistance genes are the main differences in A. baumannii between Chongqing and the eastern coastal areas of China.

Sea-level change as the driver for lake formation in the Yangtze Plain – A review

The Yangtze Plain (floodplains in the middle and lower reaches of the Yangtze River) is a region with numerous lakes, including the three largest freshwater lakes in China, i.e. Poyang Lake (PYL), Dongting Lake (DTL), and Taihu Lake (THL). The formation mechanism of these lakes offers insights into the ongoing debate concerning the interaction between tectonic activity, climate, sea-level, human impact, and Earth-surface processes. Previous studies have usually focused on individual lakes, so there remains no over-arching and consistent framework for lake formation in the region as a whole. Here we review published sedimentary and chronological records on the above three lakes and propose that sea-level change has determined their formation. During the last glacial maximum (LGM; ca 30–20 ka), with a sea-level >120 m lower than present, a landscape of incised valleys and interfluves prevailed over the entire Yangtze Plain, including the DTL area, which is >1400 km upstream from the modern river mouth, and there was no large lake on the plain. The lakes emerged in the Holocene, although more precise ages await further investigations. The glacial sea-level lowstand, with concomitant headward incision, was responsible for the extensive deeply incised landscape of the LGM, whereas the Holocene high sea-level, with resultant infilling of the incised valleys, accounted for the formation of lakes. This sea-level forcing hypothesis suggests a more far-reaching influence of sea-level change on the Yangtze Plain, and a closer relationship between Earth-surface processes and glacial–interglacial cycles (global climate) than is commonly believed. According to our newly hypothesized climate-controlled geomorphological (CCG) model, it is very likely that similar lake-forming processes could have occurred multiple times during earlier glacial–interglacial cycles, and that this pattern might also have occurred in many other river systems in the eastern coastal areas of China, as well as in other similar river plains worldwide, thus having an important role in shaping modern coastal-plain landscapes. Further work is required to test this CCG model. • We propose a model that sea level controlled the land surface processes and lake formation in Yangtze Plain. • During glacial period deep-cut landscape prevailed in the plain due to sea level lowering and concomitant headward incision. • Sea level rise after LGM raised Yangtze water level which filled up the incised valleys and depressions to form lakes. • Influence of sea level change on land surface at orbital timescales could be felt >1400 km upstream from the coast.

Nitrogen pollution and sources in an aquatic system at an agricultural coastal area of Eastern China based on a dual-isotope approach.

Nitrogen (N) pollution of water courses is a major concern in most coastal watersheds in eastern China with intensive agricultural production. We use hydrogeological and dual-isotopic approaches to analyze the N concentrations, pollution, transformations, and sources of surface water and groundwater in an agricultural watershed of the Jiaozhou Bay (JZB) area. Results showed that dissolved total N (DTN) concentrations in sub-rivers (SRs) ranged from 6.0 to 25.3mg NL-1 in the dry season and 9.1-26.7mg NL-1 in the wet season, which indicated a positive relationship with the percentages of agricultural land. Meanwhile, the dominant dissolved N species in SRs changed from nitrate (NO3-, 64-100%) to dissolved organic N (DON, 52-77%) from the dry season to the wet season and the increased DON concentrations showed a positive relationship with the planted proportions of vegetable production systems. The NO3- concentrations of groundwaters ranged from 10.6 to 121.4mg NL-1, which were over the limit for drinking water by the World Health Organization. Isotopic analysis indicated that most NO3- originated from the microbiological conversion via nitrification, whereas the deletion of denitrification was insignificant in this area. The results of the stable isotope analysis in R mixing model showed the contributions of potential NO3- sources which were in order of manure fertilizers (20.6-69.0%) > soil organic matter (19.5-53.2%) > chemical fertilizers (5.5-34.3%) > atmospheric deposition (1.3-18.8%). This study suggests that the management of crop productions and reasonable manure fertilizer application should be implemented to protect the quality of aquatic systems in the JZB area.

Effect of biochar on sweet corn and soil salinity under conjunctive irrigation with brackish water in coastal saline soil

Coastal areas of Eastern China possess substantial salt-affected lands and brackish water for agriculture usage. A novel method using biochar and conjunctive irrigation was conducted to explore the reliable utilization of these low-quality resources. Sweet corn (Z. mays L. saccharate) was grown in a coastal saline soil amended with biochar (0 and 5%). Conjunctive irrigation was carried out by alternately applying brackish water (non-saline, 2, 6, 10 dS m−1) and freshwater at the vegetative and reproductive phase. Biochar application improved sweet corn photosynthetic performance and mitigated oxidative damage as well as salt stress, further resulted in higher production and marketable value. Meanwhile, biochar amendment facilitated the availability of saline irrigation during salt sensitive stages, promoting the conjunctive irrigation with brackish water for the coastal reclamation. In addition, more salts were removed out due to biochar after leaching, and the addition of biochar reduced the salinity of the soil profile during conjunctive irrigation. In general, under conjunctive irrigation, biochar application led to enhanced growth of sweet corn and favorable salinity control in the soil profile. However, further long-term field studies should be conducted to evaluate the complex effects of biochar for agricultural production using low-quality soil and water resources in coastal regions.

Assessing the Economic-Environmental Efficiency of Energy Consumption and Spatial Patterns in China

The improvement of energy consumption efficiency represents a significant task and a critical step toward sustainable energy transformations. This study uses a data envelopment analysis (DEA) and spatial autocorrelation method to conduct comprehensive measurement and assessment research on the economic-environmental efficiency of energy consumption in 31 Chinese provinces. It then carries out a synthetic study on energy consumption efficiency in the context of temporal and spatial dimensions, analyzes the characteristics and patterns related to temporal and spatial evolution, and systematically summarizes the temporal and spatial evolution processes associated with China’s economic-environmental efficiency in energy consumption. The results show that economic efficiency and environmental efficiency, both directly related to energy consumption, are positively correlated and display a parallel and synchronizing relationship. China’s energy consumption efficiency displays an upward trend in general, although differences exist between economic efficiency and environmental efficiency about the growth rate and overall development level. In other words, economic efficiency is generally higher than environmental efficiency. A positive spatial correlation occurs between economic and environmental efficiency in energy consumption across all the Chinese provinces studied. Furthermore, some cluster characteristic can be identified. Accurately, the eastern coastal area of China with a higher efficiency represents a spatial cluster of high values, whereas the midwestern inland area of China with a lower efficiency represents a spatial cluster of low values. Therefore, a descending pattern is displayed from the east to the west. As time goes by, the extent of clustering could become more prominent, accompanied by an increasing spatial cluster of high values and a decreasing spatial cluster of low values. Accordingly, China needs to improve its energy consumption efficiency further and promote sustainable energy transformations.

Evaluation of satellite-based products for extreme rainfall estimations in the eastern coastal areas of China

ABSTRACTRemotely sensed rainfall plays an important role in providing efficient approaches for global or regional rainfall analysis. However, the accuracy of satellite-based products is mainly affected by the errors in sensor observation and retrieval algorithms, particularly with respect to extreme rainfall estimates. The objective of this study is to evaluate the accuracy of satellite-based products in capturing rainfall extremes. The eastern coastal areas of China were chosen as the case study area to compare the accuracy of three mainstream satellite-based products with respect to extreme rainfall estimates during 2003–2015 period. This included the Tropical Rainfall Measurement Mission (TRMM) rainfall product 3B42V7, the Climate Prediction Centre Morphing technique RAW (CMORPH-RAW), and the CMORPH bias-corrected product (CMORPH-CRT). In general, all satellite-based products demonstrated numerous errors in extreme rainfall estimates. Based on three different indices of extreme rainfall, it was observed that the satellite-based products underestimated the amounts of rainfall extremes and their respective average values. It was noted that CMORPH-RAW demonstrated the largest relative bias (RB) and underestimated the average extreme rainfall by −31% to −35%. Additionally, all satellite-based products exhibited poor capabilities in capturing the variations in hourly extreme rainfall processes. Finally, a simple potential flood index was developed to simulate the potential flood areas in the eastern coastal areas of China. We found that the potential flood areas can be simulated by combining the potential flood index with the amounts of rainfall derived by satellite-based products.

Enhanced nitrogen imbalances in agroecosystems driven by changing cropping systems in a coastal area of eastern China: from field to watershed scale.

Agricultural activities exacerbate nitrogen (N) imbalances in the agroecosystem by disturbing the N inputs and outputs, yet the influence of changes in cropping systems on the N balance of agroecosystems remains unclear. In this study, at the field scale, we calculated the N balance of four cropping systems, (1) traditional crops with traditional crop rotation (G-G), (2) vegetables with traditional crop rotation (V-G), (3) vegetables with vegetable rotation (V-V), and (4) greenhouse vegetables (GHV); then analyzed the influence of changes in cropping systems from 1995 to 2015 on the N balances in the agroecosystems in sub-watersheds of the Dagu River. The results indicate that N balances were higher in GHV, V-V, and V-G than G-G, due to significantly higher inputs of N fertilizers and lower N use efficiency (NUE) in vegetable cultivation compared to traditional crops. Driven by economic benefits between 1995 and 2015, V-G, V-V, and GHV replaced G-G in a considerable number of cultivation areas in the sub-watersheds. These changes resulted in an increase of 109.9-170.1% in the N balance in the agroecosystem in the sub-watersheds between 1995 and 2015. In the entire watershed, the total N surplus contribution by V-V, V-G, and GHV increased from 39.3% to 79.1% between 1995 and 2015. These findings suggest that increased vegetable cultivation contributed to the increased risk of N pollution in agricultural production. Thus, there should be a focus on the management of cropping systems to control N loss from agricultural lands.

Analyzing the variation of the precipitation of coastal areas of eastern China and its association with sea surface temperature (SST) of other seas

In this paper, we analyzed the effect of SST on the precipitation of coastal areas of the eastern China. The relationship between the precipitation and SST of different seasons based on CMDC's monthly precipitation data and NOAA's SST data from 1979 to 2016 was calculated. Analysis on the links between precipitation and SST has shown a significant correlation in winter and spring, with three positive strong oceanic signals and two negatively correlated sea areas. Meanwhile, the precipitation and SST of highly correlated regions have increased during the past 38 years. Considering the seasonal variation, precipitation presents upward trend in summer and winter with appreciable seasonal variations. For one of the highly related areas, such as the East China Sea (ECS) and the north of Philippine Sea (PS), the SST there has been increased in all four seasons. Spectral analysis also shows that the precipitation and the MEI have the same cycles about 3–5 years. Moreover, lead-lag analysis between precipitation time-series and three climate indexes (Niño 1 + 2 SST index, Niño 3 SST index and SIOD SST index) were applied. The results show that when the SSTs lead 2 to 4 months, they are highly related to the precipitation in the coastal areas of the eastern China.

Influence of vacuum preloading on vertical bearing capacities of piles installed on coastal soft soil

Land reclamation has increased significantly in the eastern coastal areas of China. The increased exploitation of offshore resources has made cast-in-situ piles more preferable in these regions. However, precise prediction of axial forces and shaft resistances of piles is particularly difficult because geological conditions are complex after the foundation is treated by vacuum preloading. In this study, two groups of cast-in-situ piles, each of which consisted of two piles installed in soft soil in Oufei Project, Wenzhou, China, were compared by conducting tests using the slow static loading method to evaluate the influence of applying vacuum preloading to deal with soft soil foundation on the vertical bearing capacities of the piles. Two piles were located in an untreated area, while the other two were located in a vacuum preloading treating area. All the piles had the same length and diameter. In addition, the axial forces and shaft resistances of piles were calculated based on the measured strains. The field tests revealed that the ultimate bearing capacities and shaft resistances of test piles were significantly improved compared to those of the piles in untreated area. The experimental results presented in this study are expected to be highly beneficial for practical engineering.

Ecosystem multifunctionality is highly related to the shelterbelt structure and plant species diversity in mixed shelterbelts of eastern China

Global change induced biodiversity loss has greatly affected ecosystem functioning, and thus the multiple services delivered by the ecosystem. Considerable recent works have focused on evaluating how species diversity changes impacts multiple ecosystem functions and services simultaneously (called ecosystem multifunctionality, EMF), but none of these evaluations were conducted in mixed shelterbelt ecosystems, which are valuable in providing multiple ecological benefits for coastal human settlements. Here, we measured the shelterbelt structure, plant species diversity, major individual ecosystem services and the EMFs of four single-species dominated mixed shelterbelts and a non-forested land along the coastal area of Eastern China and quantified how shelterbelt structure and plant species diversity affected EMF in a natural coastal scenario. Among the four mixed shelterbelts, the Populus nigra (PN) dominated mixture had significantly higher shelterbelt porosity and height, while Ligustrum compactum (LC) and Koelreuteria bipinnata (KB) dominated mixtures both had higher species richness. Concerning individual ecosystem services, the PN dominated mixture is statistically better at windbreak, C fixation and O2 releasing, plant diversity maintenance, nutrient transformation and cycling services, while the Taxodium distichum (TD) dominated mixture does better in soil and water conservation, therefore we observed the highest EMF in the PN dominated mixture. Also, we found that both shelterbelt porosity and height had significant positive effects on EMF, while no relationship was detected between shelterbelt permeability and EMF. Plant species richness and Shannon-Wiener index had significantly positive effects on EMF, but Pielow index had no significant effect on EMF. This indicated that the vertical structure of shelterbelts played a more important role than horizontal structure concerning ecosystem functioning, and EMF was not only positively affected by species richness but also species heterogenicity. These results will be informative in the policy-making and functional management of the shelterbelts and deepen the understanding of the biodiversity-ecosystem functioning relationship under alternative environmental scenarios.

Quantitative analysis of the spatio-temporal evolution of the anthropogenic transfer of lead in China

The redistribution of lead to meet human needs reflects the relationship between humans and land, and the redistribution process will influence the future evolution of the land surface. An analysis of the spatial transfer of lead was undertaken to determine the regional distribution of lead in each phase of its life cycle during 1990–2014 using the administrative unit of each province in Mainland China as the spatial unit. A quantitative analysis of the spatio-temporal evolution of the anthropogenic transfer of lead in China was conducted through a comparison of the differences in the spatio-temporal distribution of lead at different stages of its life cycle. The results showed that during 1990 to 2014, the mining of lead ore was gradually transferred from southern China to the northwest inland area and northern China, and lead within products was finally transferred to the eastern coastal area of China to complete its life cycle. The distribution of natural and social resources, supply and demand of markets, and foreign trade affect the lead anthropogenic transfer.

Determination of ultra-low level plutonium isotopes (239Pu, 240Pu) in environmental samples with high uranium

In order to measure trace plutonium and its isotopes ratio (240Pu/239Pu) in environmental samples with a high uranium, an analytical method was developed using radiochemical separation for separation of plutonium from matrix and interfering elements including most of uranium and ICP-MS for measurement of plutonium isotopes. A novel measurement method was established for extensively removing the isobaric interference from uranium (238U1H and 238UH2+) and tailing of 238U, but significantly improving the measurement sensitivity of plutonium isotopes by employing NH3/He as collision/reaction cell gases and MS/MS system in the triple quadrupole ICP-MS instrument. The results show that removal efficiency of uranium interference was improved by more than 15 times, and the sensitivity of plutonium isotopes was increased by a factor of more than 3 compared to the conventional ICP-MS. The mechanism on the effective suppress of 238U interference for 239Pu measurement using NH3-He reaction gases was explored to be the formation of UNH+ and UNH2+ in the reactions of UH+ and U+ with NH3, while no reaction between NH3 and Pu+. The detection limits of this method were estimated to be 0.55 fg mL-1 for 239Pu, 0.09 fg mL−1 for 240Pu. The analytical precision and accuracy of the method for Pu isotopes concentration and 240Pu/239Pu atomic ratio were evaluated by analysis of sediment reference materials (IAEA-385 and IAEA-412) with different levels of plutonium and uranium. The developed method were successfully applied to determine 239Pu and 240Pu concentrations and 240Pu/239Pu atomic ratios in soil samples collected in coastal areas of eastern China.

Effect of reclamation on soil organic carbon pools in coastal areas of eastern China

The coastal wetlands of eastern China form one of the most important carbon sinks in the world. However, reclamation can significantly alter the soil carbon pool dynamics in these areas. In this study, a chronosequence was constructed for four reclamation zones in Rudong County, Jiangsu Province, eastern China (reclaimed in 1951, 1974, 1982, and 2007) and a reference salt marsh to identify both the process of soil organic carbon (SOC) evolution, as well as the effect of cropping and soil properties on SOC with time after reclamation. The results show that whereas soil nutrient elements and SOC increased after reclamation, the electrical conductivity of the saturated soil extract (ECe), pH, and bulk density decreased within 62 years following reclamation and agricultural amendment. In general, the soil’s chemical properties remarkably improved and SOC increased significantly for approximately 30 years after reclamation. Reclamation for agriculture (rice and cotton) significantly increased the soil organic carbon density (SOCD) in the top 60 cm, especially in the top 0–30 cm. However, whereas the highest concentration of SOCD in rice-growing areas was in the top 0–20 cm of the soil profile, it was greater at a 20–60 cm depth in cottongrowing areas. Reclamation also significantly increased heavy fraction organic carbon (HFOC) levels in the 0–30 cm layer, thereby enhancing the stability of the soil carbon pool. SOC can thus increase significantly over a long time period after coastal reclamation, especially in areas of cultivation, where coastal SOC pools in eastern China tend to be more stable.

Using big data to improve cardiovascular care and outcomes in China: a protocol for the CHinese Electronic health Records Research in Yinzhou (CHERRY) Study

IntroductionData based on electronic health records (EHRs) are rich with individual-level longitudinal measurement information and are becoming an increasingly common data source for clinical risk prediction worldwide. However, few EHR-based...

Spatiotemporal variation of PM1 pollution in China

Understanding spatiotemporal variation of PM1 (mass concentrations of particles with aerodynamic diameter < 1 μm) is important due to its adverse effects on health, which is potentially more severe for its deeper penetrating capability into human bodies compared with larger particles. This study aimed to quantify the spatial and temporal distribution of PM1 across China as well as its ratio with PM2.5 (<2.5 μm) and relationships with meteorological parameters in order to deepen our knowledge of the drivers of air pollution in China. Ground-based monitoring PM1 and PM2.5 measurements, along with collocated meteorological data, were obtained from 96 stations in China for the period from November 2013 to December 2014. Generalized additive models were employed to examine the relationships between PM1 and meteorological parameters. We showed that PM1 concentrations were the lowest in summer and the highest in winter. Across China, the PM1/PM2.5 ratios ranged from 0.75–0.88, reaching higher levels in January and lower in August. For spatial distribution, higher PM1/PM2.5 ratios (>0.9) were observed in North-Eastern China, North China Plain, coastal areas of Eastern China and Sichuan Basin while lower ratios (<0.7) were present in remote areas in North-Western and Northern China (e.g., Xinjiang, Tibet and Inner Mongolia). Higher PM1/PM2.5 ratios were observed on heavily polluted days and lower ratios on clean days. The high PM1/PM2.5 ratios observed in China suggest that smaller particles, PM1 fraction, are key drivers of air pollution, and that they effectively account for the majority of PM2.5 concentrations. This emphasised the role of combustion process and secondary particle formation, the sources of PM1, and the significance of controlling them.

Effectiveness of protected areas for vertebrates based on taxonomic and phylogenetic diversity.

Establishing protected areas is the primary goal and tool for preventing irreversible biodiversity loss. However, the effectiveness of protected areas that target specific species has been questioned for some time because targeting key species for conservation may impair the integral regional pool of species diversity and phylogenetic and functional diversity are seldom considered. We assessed the efficacy of protected areas in China for the conservation of phylogenetic diversity based on the ranges and phylogenies of 2279 terrestrial vertebrates. Phylogenetic and taxonomic diversity were strongly and positively correlated, and only 12.1-43.8% of priority conservation areas are currently protected. However, the patterns and coverage of phylogenetic diversity were affected when weighted by species richness. These results indicated that in China, protected areas targeting high species richness protected phylogenetic diversity well overall but failed to do so in some regions with more unique or threatened communities (e.g., coastal areas of eastern China, where severely threatened avian communities were less protected). Our results suggest that the current distribution of protected areas could be improved, although most protected areas protect both taxonomic and phylogenetic diversity.

Regional differentiation of ecological conservation and its zonal suitability at the county level in China

China’s investments, financial incentives and deductions in terms of ecological conservation are based at the county level. Therefore, the monitoring and assessment of the effects of ecological conservation at the county level is important to provide a scientific basis for the assessment of the ecological and environmental quality at the county scale. This paper quantitatively estimated the dynamics of high-quality ecosystems and vegetation coverage over the past 15 years, and their relationships with the number of ecological conservation programs at the county level were analyzed. Then, the effects of ecological conservation measures on ecological changes at the county level and their regional suitability were assessed and discussed. The results showed that counties with a percentage of high-quality ecosystems greater than 50% were primarily distributed in northeastern China, southern subtropical China and the southeastern Qinghai-Tibet Plateau, and those with a percentage lower than 20% were mostly distributed in northwestern China, the southwestern karst region and the North China Plain. In recent decades, ecological conservation has focused on ecologically fragile regions; more than five ecological conservation programs have been implemented in most counties of the Three River Source Region in Qinghai Province, southeastern Tibet, western Sichuan, the Qilian Mountains, southern Xinjiang and other western regions, while only one or zero have been implemented in the eastern coastal area of China. Over the past 15 years, the proportional area of high-quality ecosystems has increased in approximately 53% of counties. The vegetation coverage of counties in the Loess Plateau, Huang-Huai-Hai Plain, Beijing-Tianjin-Hebei (Jing-Jin-Ji), Sichuan-Guizhou-Chongqing, and Guangdong-Guangxi provincial-level areas has increased significantly. However, it decreased in northern Xinjiang, central Tibet, central and eastern Inner Mongolia, the Yangtze River Delta and other regions. The relationships between the numbers of ecological conservation programs and the indicators of ecosystem restoration response, such as high-quality ecosystem and vegetation coverage, do not show positive correlations. These results suggest that ecological conservation programs should be planned and implemented according to the distribution patterns of high-quality ecosystems and that restoration measures such as afforestation should follow natural principles and regional differentiation under the background of climate change.

Research and application of ensemble forecasting based on a novel multi-objective optimization algorithm for wind-speed forecasting

Wind energy is rapidly emerging as an appealing energy option because it is both abundant and environmentally friendly. Because of the stochastic nature and intrinsic complexity of wind speed, precise and reliable wind-speed prediction is vital for wind-farm planning and the operational planning of power grids. To improve wind-speed forecasting accuracy or stability, many forecasting approaches have been proposed. However, these models usually only consider one criterion (accuracy or stability) and have limitations associated with using individual models. In this paper, an ensemble method optimized by a novel multi-objective optimization algorithm is introduced. With respect to ensemble weight coefficients, a bias-variance framework, which is formulated by a multi-objective optimization problem, is used to assess model accuracy and stability. A novel hybrid flower pollination with bat search algorithm is proposed to search for the optimal weight coefficients based on the previous step, while Pareto optimality theory provides the necessary conditions to identify an optimal solution. In addition, data decomposition and de-noising are also incorporated into the data pre-processing stage. To evaluate the forecasting ability of the proposed model, a case study of 12 wind-speed datasets from two wind farms in the eastern coastal areas of China was completed. The experimental results of this study indicate that the developed ensemble model is superior to other comparison models in terms of the high precision and stability of wind-speed prediction.