Impacts of multi-scenario land use change on ecosystem services and ecological security pattern: A case study of the Yellow River Delta

The Yellow River Delta(YRD), a critical economic zone along China's eastern coast, also functions as a vital ecological reserve in the lower Yellow River. Amidst rapid industrialization and urbanization, the region has witnessed significant land use/cover changes(LUCC), impacting ecosystem services(ES) and ecological security patterns(ESP). Investigating LUCC's effects on ES and ESP in the YRD is crucial for ecological security and sustainable development. This study utilized the PLUS model to simulate 2030 land use scenarios, including natural development(NDS), economic development(EDS), and ecological protection scenarios(EPS). Subsequently, the InVEST model and circuit theory were applied to assess ES and ESP under varying LUCC scenarios from 2010 to 2030. Findings indicate:(1) Notable LUCC from 2010 to 2030, marked by decreasing cropland and increasing construction land and water bodies.(2) From 2010 to 2020, improvements were observed in carbon storage,water yield, soil retention, and habitat quality, whereas 2020–2030 saw increases in water yield and soil retention but declines in habitat quality and carbon storage. Among the scenarios, EPS showed superior performance in all four ES.(3) Between 2010 and 2030, ecological sources, corridors, and pinchpoints expanded, displaying significant spatial heterogeneity. The EPS scenario yielded the most substantial increases in ecological sources,corridors, and pinchpoints, totaling 582.89 km^(2), 645.03 km^(2),and 64.43 km^(2), respectively. This study highlights the importance of EPS, offering insightful scientific guidance for the YRD's sustainable development.

Factors Influencing the Thermal Conductivity of Silt in the Yellow River Delta

The thermal conductivity of marine sediments is an important thermophysical parameter in the study of seafloor heat flow and marine engineering construction.Understanding the effect of thermal conductivity of marine sediments in the environment has a major engineering value and theoretical significance.In this work,a modified test method was used to measure the thermal conductivity of silt in the Yellow River Delta under different void ratios,moisture contents,temperatures,and salinities.Results showed that the thermal conductivity of silt in the Yellow River Delta decreased with the increase in the void ratio and increased with the water content.Compared with sand and clay,silt in the Yellow River Delta was the least affected by the void ratio and moisture content.Under low temperatures,the heat transfer of soil was controlled by the average velocity of the phonons;therefore,the thermal conductivity of silt in the Yellow River Estuary increased with temperature.The thermal conductivity of pore water decreased with increasing salinity.Moreover,certain salinity levels resulted in a phenomenon known as the‘compressing twin electrical layer’,which led to an increase in the contact area between soil particles.With the increase in salinity,the thermal conductivity of silt in the Yellow River Delta experiences an initial decline and a subsequent increase.The proposed thermal conductivity test method is more accurate than the existing technique,and the findings provide a basis for further study on the thermal characteristics of submarine sediments.

Dynamics Characteristics and Topographic Profile Shaping Process of Feiyan Shoal at the Yellow River Delta

Feiyan Shoal is a sub Yellow River Delta, which was formed from Jan. 1964 to May 1976, when the Yellow River entered sea via Diaokou Channel. Since the terminal reach shifted to Qingshuigou channel in 1976, Feiyan Shoal has been experiencing severe erosion and retreat. This paper explains the evolutionary characteristics of the typical profile of Feiyan Shoal from the perspective of dynamical force and sediments＇ characteristics. All this is on the basis of the data of topographic profiles observed since the 1970s and the samples of hydrology and sediments collected in situ in Apr. 2004, the analysis of the retreating distance, and the tidal and wave friction velocity distribution. Feiyan Shoal topographical profile has experienced a course of ＂fast erosion and retrogression - slow eroding modulation - fluctuate triggering change＂ in recent 30 years, which is also the gradual disappearing process of the delta front. The different intensity of sediment erosion resistance is the main reason for the erosion speed changes. Due to the hydrodynamic force changes, the water depth range of maximum retreating distance and between erosion and progradation became shallow. It indicates that the storm tide will still be the triggering force of seashore topographic profile evolutions in the future.

Tupu methods of spatial-temporal pattern on land use change:a case study in the Yellow River Delta

Comprehensive study on land-use change of spatial pattern and temporal process is the key component in LUCC study nowadays. Based on the theories and methods of Geo-information Tupu (Carto-methodology in Geo-information, CMGI), integration of spatial pattern and temporal processes of land-use change in the Yellow River Delta (YRD) are studied in the paper, which is supported by ERDAS and ARC/INFO software. The main contents include: (1) concept models of Tupu by spatial-temporal integration on land-use change, whose Tupu unit is synthesized by "Spatial·Attribute·Process" features and composed of relatively homogeneous geographical unit and temporal unit; (2) data sources and handling process, where four stages of spatial features in 1956, 1984, 1991, and 1996 are acquired; (3) integration of series of temporal-spatial Tupu, reconstruction series of "Arising" Tupu, spatial-temporal Process Tupu and the spatial temporal Pattern Tupu on land-use change by remap tables; (4) Pattern Tupu analysis on land-use change in YRD during 1956-1996; and (5) spatial difference of the Pattern Tupu analysis by dynamic Tupu units. The various landform units and seven sub-deltas generated by the Yellow River since 1855 are different. The Tupu analysis on land-use in the paper is a promising try on the comprehensive research of "spatial pattern of dynamic process" and "temporal process of spatial pattern" in LUCC research. The Tupu methodology would be a powerful and efficient tool on integrated studies of spatial pattern and temporal process in Geo-science.

Effect of Hydrological Connectivity on Soil Carbon Storage in the Yellow River Delta Wetlands of China

Hydrological connectivity has significant effects on the functions of estuarine wetland ecosystem.This study aimed to examine the dynamics of hydrological connectivity and its impact on soil carbon pool in the Yellow River Delta,China.We calculated the hydrological connectivity based on the hydraulic resistance and graph theory,and measured soil total carbon and organic carbon under four different hydrological connectivity gradients(Ⅰ0‒0.03,Ⅱ0.03‒0.06,Ⅲ0.06‒0.12,Ⅳ0.12‒0.39).The results showed that hydrological connectivity increased in the north shore of the Yellow River and the south tidal flat from 2007 to 2018,which concentrated in the mainstream of the Yellow River and the tidal creek.High hydrological connectivity was maintained in the wetland restoration area.The soil total carbon storage and organic carbon storage significantly increased with increasing hydrological connectivity fromⅠtoⅢgradient and decreased inⅣgradient.The highest soil total carbon storage of 0‒30 cm depth was 5172.34 g/m^(2),and organic carbon storage 2764.31 g/m^(2)inⅢgradient.The hydrological connectivity changed with temporal and spatial change during 2007‒2018 and had a noticeable impact on soil carbon storage in the Yellow River Delta.The results indicated that appropriate hydrological connectivity,i.e.0.08,could effectively promote soil carbon storage.

Increased salinity and groundwater levels lead to degradation of the Robinia pseudoacacia forest in the Yellow River Delta

Forest degradation is a worldwide problem,although its causes vary due to geographical and climatic differences and man-made causes.In recent years,the Robinia pseudoacacia forest in the Yellow River Delta has suffered severe degradation.The causative mechanisms were investigated in the field over two years,and the results show that increased forest degradation was reflected by increased tree mortality,high leaf and soil sodium salt levels and groundwater depth.Average tree diameters decreased,and leaf chlorophyll and soil microbial contents decreased.Redundancy discriminate analysis(RDA)showed that degradation of the forest was correlated positively with soil salt content,but negatively with groundwater depth.Correlation analysis showed that 0.79%–0.95%soil salt content and above 1.20 m groundwater depth caused the death of R.pseudoacacia trees due to localized anthropogenic economic activities,such as rice farming,that disrupted the original water–salt balance.Measures are recommended to prevent further degradation and restore degraded forests.

Saline-alkali land in the Yellow River Delta: amelioration zonation based on GIS

Soil salinization is one of the major land degradation types and has greatly influenced sustainable agricultural development. Zonation of saline-alkali land is the precondition for effective amelioration. The present situation of saline-alkali land is monitored by remote sensing image processing. Causes for land salinization are analyzed, especially the two key factors, ground water depth and its mineralization degree, are analyzed by using long-term observation data. Previously, zonation of saline-alkali soil was made descriptively and artificially. Based on the present situation of saline-alkali land, ground water depth and ground water mineralization degree, the zonation of saline-alkali land for amelioration in the Yellow River Delta was completed quantitatively. Four different types of saline-alkali land amelioration zones are delineated, namely, easy ameliorated zone, relatively difficult ameliorated zone, difficult ameliorated zone and unfavorable ameliorated zone. Countermeasures for ameliorating saline-alkali soils are put forward according to ecological conditions of different saline-alkali land zones.

Effects of Tidal Channels and Roads on Landscape Dynamic Distribution in the Yellow River Delta, China

Landscape characters in estuarine regions generally controlled by tidal regimes and human activities like road construction.In this work,tidal channels and road construction in the Yellow River Delta(YRD)were extracted by visual interpretation methods so as to decipher impacts of tidal channel development and road construction on landscape patch change during 1989–2016.Spatial distribution history of three wetlands,which covered by Phragmites australis(freshwater marsh,FM),Suaeda salsa(salt marsh,SM),and mudflats(MD)were also established.Results indicated that tidal channel,number,frequency,and fractal dimension were all the maximum in 2003,and the minimum in 1998,respectively.Road length,number,and density showed increasing trend during 1989–2016.MD were the predominant landscape type,followed by FM and SM during 1989-2016.Principal component analysis implied two extracted factors,F1 and F2,which could represent 91.93% of the total variations.F1 mainly proxied tidal channel development,while F2 represented road construction.A multiple linear regression analysis showed positive effects of both F1 and F2 on FM patch numbers and negative impacts on SM patch areaes with R^2 values of 0.416 and 0.599,respectively.Tidal channels were negatively related to MD patch numbers,while roads were positively related to that.In any case,road construction showed larger impacts on landscape type shifting than that of tidal channel development in the YRD.

Soil Organic Carbon Contents and Stocks in Coastal Salt Marshes with Spartina alterniflora Following an Invasion Chronosequence in the Yellow River Delta,China

Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.

Characteristics of Mulching Plastic Film Residue in Cotton Fields in the Yellow River Delta

In order to get a clear picture of distribution characteristics of mulching plastic film residue in cotton fields in the Yellow River Delta and make scientific pollution prevention and control strategies, an investigation was conducted in Dongying City. Five typical cotton fields were chosen, and then the number, distri- bution density and area of residual film were measured. The results showed that the residual film was 18. 84-53. 53 kg/hm^2 in cotton fields for more than 20 years, and the differences between fields were larger. The residual density was 225-340 thousand per hectare. There were great differences among residual pieces. The proportion of residual pieces over 25 cm^2 was 94. 1%, that between 100 cm^2 and 500 cm^2 was more than 50. 0%, and that bigger than 500 cm^2 was about 21. 0%. In the Yellow River Delta cotton region, large, thin and difficult to recovery were the main characteristics of mulching plastic film residue, and it had the possibility of mi- grating to deep soil. Thus, the ecological risk of mulching plastic film residue was higher. Key words The Yellow River Delta; Cotton field; Residue of mulching plastic film; Distribution characteristic

Study on Land Use Changes in the Yellow River Delta from 1980 to 2010

Taking the Yellow River Delta for example, this paper applied remote sensing and GIS to explore land use changes in the local area from 1980 to 2010. The results showed that arable land, and urban and rural construction land were major land use types in the Yellow River Delta, unused land also took a large ratio; land use changes occurred mainly in coastal regions, in terms of change matrix, 25.46% of the grassland was reclaimed as arable land, unused land also witnessed great changes, specifi cally, 11.14% turned to arable land, 23.25% to construction land. This study provided references for the land use planning and development of the local area.

Total Factor Productivity and Influence Factors of Economic Environment in the Yellow River Delta

The paper analyzed total factor productivity of Binzhou City, and key factors that influence its economic growth and effluent discharge. The results showed that(i) production efficiency of the city during 2005–2013 kept stable, mean of Malmquist-Luenberger index was 1.044,9 without considering effluent discharge, and the average annual increase rate was 4.49%, and that was 1.020,4 considering effluent discharge, the average annual increase rate was 2.04%, and the increase rate reduced by 2.45%.(ii) GDP growth showed significant negative correlation and positive correlation with capital input and energy input, but insignificant negative correlation and positive correlation with labor force input and technological progress.(iii) Effluent discharge showed insignificant negative correlation and positive correlation with capital input and energy input, but significant negative correlation and positive correlation with labor force input and technological progress.

Evaluation of Coordinated Development of Urbanization and Ecological Environment in the Efficient Ecological Economic Zone of the Yellow River Delta

Based on the statistical data of urbanization development level and ecological environment in the Yellow River Delta during 2009-2014,a comprehensive index system for the coordinated development of urbanization and ecological environment was established to evaluate the coordinated development level. The results showed that the coordinated development level of urbanization and ecological environment in the Yellow River Delta was generally high during 2009-2014. The development level of urbanization was higher than that of ecological environment on the whole,that is,the development of ecological environment lagged behind. The development of urbanization in the region was relatively slow during 2009-2011 but rapid during 2012-2014. The development level of ecological environment was relatively stable and always increased.

The Rise of the yellow River Delta

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Geospatial-temporal analysis of land-use changes in the Yellow River Delta during the last 40 years

Comprehensive study on land-use change of spatial pattern and temporal process is the key component in land use/land cover changes (LUCC) study nowadays. According to the theories and methods of Geo-information Tupu (Carto-methodology in Geo-information, CMGI) for geospatial and temporal analysis and integration models of spatial pattern and temporal processes in GIS, the paper puts forward Tupu methodology of land-use change and names the basic synthetic unit of spatial-temporal information Tupu unit. Tupu unit is the synthetic unit for geospatial-temporal analysis, which is synthesized by “space·attribute·process”features and composed of relatively homogeneous geographic unit and temporal unit. Based on the spatial features of 4 stages of land-use change in 1956, 1984, 1991, and 1996, a series of Tupu on land-use change in the Yellow River Delta (YRD) are created and studied in the paper, which includes 3 temporal units of spatial-temporal Tupu, process Tupu of land-use changes during the last 40 years, and reconstructions of a series of “arisen”Tupu, “arisen”process Tupu and pattern Tupu on land-use changes in the last 40 years by remapping tables of a reclassifying system. There are 3 methods of Tupu analysis on land-use change that are used to disclose change processes of land-use spatial conversion in YRD, such as spatial query and statistics, order of Tupu units by area and land-use conversion matrixes. In order to reveal the spatial pattern of land-use change processes, we analyze spatial-temporal changes of each Tupu above in various temporal units and spatial difference of pattern Tupu in the last 40 years by dynamic Tupu units. Tupu analysis on regional land-use is a promising trial on the comprehensive research of “spatial pattern of dynamic process”and “temporal process of spatial pattern”in LUCC research. The geo-information Tupu methodology would be a powerful and efficient tool on integrated studies of spatial pattern and temporal process in geoscience.

Influences of chronic contamination of oil field exploitation on soil nematode communities at the Yellow River Delta of China

Oil production related activities have led to many environmental problems.Around 80%of the total output of crude oil is generated from terrestrial oilfields in the world.However,the impact of oil exploitation procedures on soil animal communities has not been fully understood.This study investigated the responses of soil nematode communities to the oil exploitation activities in the Yellow River Delta of China.By setting 10 oilfield sites and 5 relatively uncontaminated sites(controls),we found that the content of soil total petroleum hydrocarbons(TPH)was significantly higher at oilfield sites than at controls.With a longer oil exploitation history,the content of soil TPH increased.Soil nematode community structure at oilfield sites was largely different from that at controls.Soil nematodes were significantly less abundant but more diverse at oilfield sites than at controls.The proportions of fungal feeders were significantly lower at oilfield sites than at controls,attaining only half of those at controls.The nematode trophic diversity and genus number negatively correlated with the duration of petroleum exploitation history.This study elucidated the difference in soil nematode communities caused by oilfield exploitation and indicated that the nematode diversity was most obviously influenced by the soil TPH content and the oil exploitation history.

Spatial and Temporal Pattern Changes and Driving Forces:Analysis of Salinization in the Yellow River Delta from 2015 to 2020

China’s Yellow River Delta represents a typical area with moist semi-humid soil salinization,and its salinization has seriously affected the sustainable use of local resources.The use of remote sensing technology to understand changes in the spatial and temporal patterns of salinization is key to combating regional land degradation.In this study,a feature space model was constructed for remote sensing and monitoring land salinization using Landsat 8 OIL multi-spectral images.The feature parameters were paired to construct a feature space model;a total of eight feature space models were obtained.An accuracy analysis was conducted by combining salt-loving vegetation data with measured data,and the model demonstrating the highest accuracy was selected to develop salinization inversion maps for 2015 and 2020.The results showed that:(1)The total salinization area of the Yellow River Delta displayed a slight upward trend,increasing from 4244 km^(2) in 2015 to 4629 km^(2) in 2020.However,the area’s salting degree reduced substantially,and the areas of saline soil and severe salinization were reduced in size;(2)The areas with reduced salinization severity were mainly concentrated in areas surrounding cities,and primarily comprised wetlands and some regions around the Bohai Sea;(3)Numerous factors such as the implementation of the“Bohai Granary”cultivation engagement plan,increase in human activities to greening local residential living environments,and seawater intrusion caused by the reduction of sediment contents have impacted the distribution of salinization areas in the Yellow River Delta;(4)The characteristic space method of salinization monitoring has better applicability and can be promoted in humid-sub humid regions.

Fluorescence characterization and microbial degradation of dissolved organic matter leached from salt marsh plants in the Yellow River Delta

Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods In this study,we conducted laboratory experiments to investigate the processes of DOM leaching from three common marsh plants(Phragmites australis,Suaeda salsa and Aeluropus littoralis)collected from the Yellow River Delta(YRD)salt marsh in October 2016.The YRD is one of the largest and most well-protected coastal ecosystems on the east coast of China.Important Findings We found that the plant leaves released DOM at much higher concentrations than the plant roots or stems,as measured by the dissolved organic carbon(DOC)and dissolved nitrogen(DN).On average,15%of the biomass C and 30%of the biomass N were released from the plant leaves as DOC and DN during the 27-day incubation period.The DOM released from the plants was very labile,and 92.4%-98.1%of the DOC and 88.0%-94.6%of the DN released from the plants were consumed by bacteria during the 27-day incubation period.The fluorescence characteristics of the plant-released DOM indicated that chromophoric dissolved organic matter was a major fraction of the DOM and that protein-like components were the primary organic fractions released from the plants.Bacterial degradation altered both the fluorescence properties and the chemical composition of the DOM.The results of the laboratory experiments were well supported by the field investigation,which indicated that a large amount of DOM was outwelled from the YRD salt marshes in late autumn.Our study suggests that the DOM released from the biomass of salt marsh plants provides an important source of both DOC and DN for marsh and coastal waters.The highly labile DOC and DN provide essential food sources to support microbial communities in the YRD salt marsh and adjacent coastal waters.

Response of reed community to the environment gradientwater depth in the Yellow River Delta, China

We investigated and monitored a reed community in the fields.Data on the bio-ecological characteristics and β-diversity of reed communities in different environmental gradients(mainly based on water depth)of the Yellow River Delta were collected through multianalysis,extremum analysis and β-diversity index analysis.In accordance with the square sum of deviations(Ward)cluster analysis,10 sampling plots were divided into six types with the dominant plants in different plots varying according to the change in environmental gradients.The dominant plants in these plots varied from aquatic plants to xerophytes and salt tolerant plants as water depth decreased.The average height and diameter of the reeds at breast level were significantly correlated with the average water depth.The fitness curves of average density and coverage with average water depth were nonlinear.When the average water depth was 0.3 m,the average density and coverage of reeds reached the apex value,while the height and diameter of the reeds at breast level increased with the water depth.There were obvious changes to the environmental gradient in the Yellow River Delta.The transitional communities were also found to exist in the Yellow River Delta by β-diversity analysis.Vicarious species appeared with the change in water depth.The occurrence of substitute species is determined by the function of common species between adjacent belts.The different functions of common species led to differences in community structure and function and differences in dominant plants.The result reflects the variations of species present in different habitats and directly reflects environmental heterogeneity.The values of β-diversity indices of adjacent plots were higher than those of nonadjacent plots.There are transition zones between the xerophytes and aquatic plants in the Yellow River Delta.In an aquatic environment,the similarity of reed community is higher than that of xeromorphic plants.The β-diversity index can reflect plant succession trends caused by the change in environmental gradients in the Yellow River Delta.The β-diversity index reveals plant responses to changes in environmental gradient and is helpful in observing changes in patterns of species diversity in relation to environmental gradient change and evolving trends in the future,which in turn plays a prominent role when environmental water requirements of wetland are discussed.

Dynamics of Bottom Boundary Layers in the Yellow River Subaqueous Delta Based on Long-Term In-Situ Observations

Objective In geo-marine science,the generalized bottom boundary layer（BBL）represents a layer between sediments and seawater.The BBL plays an important role in geological,geobiochemical,geophysical and geotechnical research because it is the connection region of hydrosphere,