Uphill or downhill?Cropland use change and its drivers from the perspective of slope spectrum

The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic factors.However,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains rare.To address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the Yangtze River Basin(YRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope spectrum.Results showed that the slope spectrum curves of cropland area-frequency in the YRB showed a first upward then a downward trend.The change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution patterns.Quantitative analysis of morphological parameters of cropland slope spectrum revealed that the further down the YRB,the stronger the flattening characteristics,the more obvious the concentration.The province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was Zhejiang.The most common cropland use change type in the YRB was horizontal expansion type.The factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study period.This research is of practical significance for the rational utilization of cropland at the watershed scale.

Response of ecosystem carbon storage to land use change from 1985 to 2050 in the Ningxia Section of Yellow River Basin,China

Regional sustainable development necessitates a holistic understanding of spatiotemporal variations in ecosystem carbon storage(ECS),particularly in ecologically sensitive areas with arid and semi-arid climate.In this study,we calculated the ECS in the Ningxia Section of Yellow River Basin,China from 1985 to 2020 using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model based on land use data.We further predicted the spatial distribution of ECS in 2050 under four land use scenarios:natural development scenario(NDS),ecological protection scenario(EPS),cultivated land protection scenario(CPS),and urban development scenario(UDS)using the patch-generating land use simulation(PLUS)model,and quantified the influences of natural and human factors on the spatial differentiation of ECS using the geographical detector(Geodetector).Results showed that the total ECS of the study area initially increased from 1985 until reaching a peak at 402.36×10^(6) t in 2010,followed by a decreasing trend to 2050.The spatial distribution of ECS was characterized by high values in the eastern and southern parts of the study area,and low values in the western and northern parts.Between 1985 and 2020,land use changes occurred mainly through the expansion of cultivated land,woodland,and construction land at the expense of unused land.The total ECS in 2050 under different land use scenarios(ranked as EPS>CPS>NDS>UDS)would be lower than that in 2020.Nighttime light was the largest contributor to the spatial differentiation of ECS,with soil type and annual mean temperature being the major natural driving factors.Findings of this study could provide guidance on the ecological construction and high-quality development in arid and semi-arid areas.

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.

Spatially Heterogeneous Response of Carbon Storage to Land Use Changes in Pearl River Delta Urban Agglomeration, China

Carbon storage of terrestrial ecosystems plays a vital role in advancing carbon neutrality. Better understanding of how land use changes affect carbon storage in urban agglomeration will provide valuable guidance for policymakers in developing effective regional conservation policies. Taking the Pearl River Delta Urban Agglomeration(PRDUA) in China as an example, we examined the heterogeneous response of carbon storage to land use changes in 1990–2018 from a combined view of administrative units and physical entities. The results indicate that the primary change in land use was due to the expansion of construction land(5897.16 km2). The carbon storage in PRDUA decreased from 767.34 Tg C in 1990 to 725.42 Tg C in 2018 with a spatial pattern of high wings and the low middle. The carbon storage loss was largely attributed to construction land expansion(55.74%), followed by forest degradation(54.81%). Changes in carbon storage showed significant divergences in different sized cities and hierarchical boundaries. The coefficients of geographically weighted regression(GWR) reveal that the alteration in carbon storage in Guangzhou City was more responsive to changes in construction land(-0.11) compared to other cities, while that in Shenzhen was mainly affected by the dynamics of forest land(8.32). The change in carbon storage was primarily influenced by the conversion of farmland within urban extent(5.05) and the degradation of forest land in rural areas(5.82). Carbon storage changes were less sensitive to the expansion of construction land in the urban center, urban built-up area, and ex-urban built-up area, with the corresponding GWR coefficients of 0.19, 0.04, and 0.02. This study necessitates the differentiated protection strategies of carbon storage in urban agglomerations.

Analysis of Land Use Change and Driving Factors in Mojiang County Based on PLUS Model

[Objectives]To explore the characteristics of land use change and its main influencing factors in Mojiang County from 2000 to 2020,and try to provide a scientific reference for alleviating the contradiction between man and land in Mojiang County and realizing the sustainable development of regional land resources.[Methods]Based on the land cover data and socio-economic data of Mojiang County from 2000 to 2020,the dynamic degree of land use,land use transfer matrix and center-of-gravity transfer model were calculated,and the temporal and spatial change characteristics and driving factors of various types of land use were calculated by PLUS model.[Results]From 2000 to 2020,the area and proportion of grassland,waters and construction land in Mojiang County showed an upward trend,while the area and proportion of cultivated land and forest land showed a downward trend.Among them,cultivated land was mainly converted into forest land and grassland,and some were converted into waters and construction land;forest land was mainly converted into cultivated land and grassland,and part of it was converted into waters and construction land.From 2000 to 2020,the center-of-gravity of cultivated land,forest land and construction land in Mojiang County moved to the southeast of the county,and the moving rates were 0.66,1.97 and 10.58 km/yr,respectively;the center-of-gravity of grassland and waters moved to the southwest of the county,and the moving rates were 1.30 and 20.20 km/yr,respectively.Distance from road,distance from government and distance from waters are the main driving forces affecting land use change in Mojiang County;the forecast shows that in 2040,the area of grassland and forest land in Mojiang County will continue to decrease,the area of cultivated land will turn to rise,and the area of waters and construction land will continue to rise.[Conclusions]Reasonable planning and optimizing the allocation of cultivated land and forest land structure and strict control of the expansion scale of construction land are necessary measures to ensure the coordinated development of regional land rational use and economic construction.

Temporal and Spatial Evolution Characteristics of Habitat Quality in Kunming Based on Land Use Change

[Objectives]To analyze the change of urban habitat quality in different periods and study the influence of land use change on habitat quality,which plays an important role in regional sustainable development.[Methods]Taking Kunming as an example,based on land use change,InVEST model was used to evaluate the temporal and spatial evolution characteristics of habitat quality.[Results]During 2000-2020,cultivated land,grassland and woodland in Kunming decreased by 277.43,324.99 and 141.72 km 2,respectively;land use transfer presented obvious stage characteristics,with cultivated land,grassland and woodland changing into construction land as the main characteristics during 2005-2010,and 2015-2020.The average value of habitat quality index in Kunming decreased from 0.3119 to 0.3022,showing a downward trend as a whole;the spatial distribution pattern of habitat quality was"low in the middle and high around"(the high value areas of habitat quality are mainly distributed around Kunming,while the low value areas are mainly distributed in the urban aggregation areas of Kunming).[Conclusions]This study can provide theoretical support for future land use planning.

Considering Regional Connectivity and Policy Factors in the Simulation of Land Use Change in New Areas:A Case Study of Nansha New District,China

Numerous emerging development areas worldwide are receiving attention;however,current research on land use change simulation primarily concentrates on cities,urban clusters,or larger scales.Moreover,there is a limited focus on understanding the impact of regional connectivity with surrounding cities and policy factors on land use change in these new areas.In this context,the present study utilizes a cellular automata(CA)model to investigate land use changes in the case of Nansha New District in Guangzhou,China.Three scenarios are examined,emphasizing conventional locational factors,policy considerations,and the influence of regional connectivity with surrounding cities.The results reveal several key findings:(1)Between 2015 and 2021,Nansha New District experienced significant land use changes,with the most notable shifts observed in cultivated land,water area,and construction land.(2)The comprehensive scenario exhibited the highest simulation accuracy,indicating that Nansha New District,as an emerging area,is notably influenced by policy factors and regional connectivity with surrounding cities.(3)Predictions for land use changes in Nansha by 2030,based on the scenario with the highest level of simulation accuracy,suggest an increase in the proportion of cultivated and forest land areas,alongside a decrease in the proportion of construction land and water area.This study contributes valuable insights to relevant studies and policymakers alike.

Response of Ecosystem Service Value Based on Land Use Changes and Analysis of its Driving Factors in Typical Hilly Region with Red Soil

The contribution rate of ecosystem service value variation was used to analyze the effects of land use changes on the changes of ecosystem service value in Xingguo County during 1996-2005.Grey integrated correlation was employed to explore the contribution level of the indicators such as total population,urbanization level,proportion of primary industry and investment of social fixed assets on ecosystem service value,and the correlation analysis was also carried out.The results showed that the ecosystem service value in Xingguo County during 1996-2005 mainly was woodland,and the decrease of woodland area was the major reason for the sustained reduction of ecosystem service value.With the further increase of market demand and the incentives of local government,the garden area rapidly increased during 2001-2005,and the influence degree of garden towards the changes of ecosystem service value was only second to woodland,ranking No.2.Four socio-economic indicators had different correlation degree with ecosystem service value during the different research periods.Total population,urbanization level and proportion of primary industry had high correlation degree with ecosystem service value,whereas the influence degree of various socio-economic indicators on ecosystem service value was equal with each other day by day.Urbanization level,investment of social fixed assets and total population had significant negative correlation with ecosystem service value,while the proportion of primary industry had positive correlation with ecosystem service value.

Impacts of Land Use Change on Ecosystem Service Value in Yanchi County of Ningxia

Based on TM image data in 1989, 1995, 1999, 2003, 2006 and 2009 of Yanchi County of Ningxia, the land use date of Yanchi County in each year were extracted supported by RS and GIS technology, and used to analyze the dynamic change of land use. The land use data were studied for estimating the change of ecosystem services value caused by the land use change of Yanchi County, using the evaluation method of China terrestrial ecosystem services value. The results showed that the changes of land use were obvious during 1989 to 2009. The area of woodland and construction land had an increasing tendency; grassland area changed from decreasing to increasing, which was in contrary to farmland and un-used land areas （from increasing to decreasing）; water area fluctuated slightly. The ecosystem services value of Yanchi County had an increasing tendency during 1989 to 1995, because the increasing woodland area had took the major role in raising the total ecosystem services value. The grassland accounted for a large proportion of the total ecosystem service value of Yanchi County, with its contribution rate from 49.8% to 60.4%. And the composition of the ecosystem services value of Yanchi County happened benign change for the increasing contribution rate of woodland. The ecosystem services value sensitivity index of each land use type was less than 1, indicating that the ecosystem services value of Yanchi County lacks flexibility on its service value index, and the research results are reliable.

Geo-information Tupu Analysis of Land Use Change in Haihe River Basin

[Objective] This study was to provide basis for the scientific management of land use in Haihe River Basin （HRB） through the quantitative exploration of the land use conversion, changes of intensity and spatial distribution in this region. [Method] With the support of remote sensing technology and geographic information technology, the land use maps of the study area in 40 years （1970-2010） were in- terpreted and plotted. Four kinds of tupu, namely, land use change tupu, process tupu, arising tupu and evolution mode tupu were built through the spatial overlay of the land use maps to analyze the change rules of land use patterns. [Result] The conversion of arable land to construction land was the main characteristics of land use changes in HRB for the 40 years; the area of non-stable region accounted for 35% of the total, indicating that the land use changed remarkably, thus, it was nec- essary to strengthen the scientific land management in HRB; the new conversions to all land use patterns were all the lowest in 1980-1990, indicating that land use changed slowly during this period. [Conclusion] The results indicate that, compared with conventional transfer matrix method, geo-information tupu has obvious advantage in analyzing land use changes that it can demonstrate the spatial distribution of interest region, display the multi-dimensional spatial information.

Spatial patterns and driving forces of land use change in China during the early 21st century

Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science （LCS） in the study of global environmental change. Based on remotely sensed data of land use change with a spatial resolution of 1 km × 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21 st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the ＂Grain for Green＂ policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of ＂Western Development＂, ＂Revitalization of Northeast＂, coupled with rapidly economic development during this period.

Spatial-Temporal Pattern and Driving Forces of Land Use Changes in Xiamen

Using Landsat TM data of 1988, 1998 and 2001, the dynamic process of the spatial-temporal characteristics of land use changes during 13 years from 1988 to 2001 in the special economic zone of Xiamen, China was analyzed to improve understanding and to find the driving forces of land use change so that sustainable land utilization could be practiced. During the 13 years cropland decreased remarkably by nearly 11304.95 ha. The areas of rural-urban construction and water body increased by 10 152.24 ha and 848.94 ha, respectively. From 1988 to 2001, 52.5% of the lost cropland was converted into rural-urban industrial land. Rapid urbanization contributed to a great change in the rate of cropland land use during these years. Land-reclamation also contributed to a decrease in water body area as well as marine ecological and environmental destruction. In the study area 1) urbanization and industrialization, 2) infrastructure and agricultural intensification, 3) increased affluence of the farming community, and 4) policy factors have driven the land use changes. Possible sustainable land use measures included construction of a land management system, land planning, development of potential land resources, new technology applications, and marine ecological and environmental protection.

Land Suitability Assessment and Land Use Change in Fujian Province,China

To present the current status of land quality and distribution and the trends in land use change, the physical suitability of cropland and forestland and the associated changes in Fujian Province were evaluated and analyzed using data obtained from geographical information systems (GIS) and remote sensing (RS).Of the total land area of Fujian Province,first class suitable cropland accounted for only 4.21%, whereas unsuitable cropland accounted for 84.78%. The percentage of first class suitable cropland in the southeastern region (5.32%) was much higher than that in the northwestern area (2.91%).Only 13.63% of the existing cropland area consisted of first class cropland and 70.08% was classified as unsuitable for cultivation.Of the total land area of Fujian Province,the first class forestland comprised 55.25% and the unsuitable forestland (including third class) comprised 21.2%.The percentage of unsuitable forest area in the existing forestland was only 5.5%.From 1996 to 2001, cropland and unused land decreased significantly, whereas forestland and land used for urban and transport increased rapidly.Therefore,the major tasks ahead will be the land development for full grain production potential,the better coordination of allocating land to different uses, and the regulation inappropriate activities that damage agricultural ecosystems.

Quantifying Land Use Change in Zhejiang Coastal Region,China Using Multi-Temporal Landsat TM/ETM+Images

Landsat Thematic Mapper （TM） and Enhanced Thematic Mapper Plus （ETM＋） images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes （LUCC） in the Zhejiang coastal region with a stratified unsupervised classification technique in conjunction with visual interpretation and to attempt an identification of the socioeconomic driving forces. In level I an overall accurate classification was achieved using a modified Anderson＇s Ⅰ/Ⅱ/Ⅲ-level classification scheme. The overall accuracy of the land use classification at Anderson level Ⅰ were 89.7% （1985）, 91.6% （1993）, and 90.4% （2001）. The most rapid land use change was a dramatic increase in urban or built-up areas, which quadrupled from 1985 to 2001. Over 90% of this newly expanded built-up area was originally paddy fields or other croplands. In different parts of the Zhejiang coastal region, urban land expansion was spatially uneven. Temporally, land use development did not stabilized, and the two study periods of time （1985-1993 and 1993-2001） had different transition styles. Socioeconomic factors, such as gross domestic product, total population, and financial expenditure, were all highly correlated with the expansion of urban or built-up areas. Based on the degree of urban sprawl and socioeconomic factors, cities and towns were further divided into six subgroups, which may help decision makers improve land use for the region.

Simulation of Effects of Land Use Change on Climate in China by a Regional Climate Model

Climate effects of land use change in China as simulated by a regional climate model (RegCM2) are investigated. The model is nested in one-way mode within a global coupled atmosphere-ocean model (CSIRO R21L9 AOGCM). Two multi-year simulations, one with current land use and the other with potential vegetation cover, are conducted. Statistically significant changes of precipitation, surface air temperature, and daily maximum and daily minimum temperature are analyzed based on the difference between the two simulations. The simulated effects of land use change over China include a decrease of mean annual precipitation over Northwest China, a region with a prevalence of arid and semi-arid areas; an increase of mean annual surface air temperature over some areas; and a decrease of temperature along coastal areas. Summer mean daily maximum temperature increases in many locations, while winter mean daily minimum temperature decreases in East China and increases in Northwest China. The upper soil moisture decreases significantly across China. The results indicate that the same land use change may cause different climate effects in different regions depending on the surrounding environment and climate characteristics.

Groundwater quality and land use change in a typical karst agricultural region:a case study of Xiaojiang watershed,Yunnan

Taking the typical karst agricultural region, Xiaojiang watershed in Luxi of Yurman Province as a research unit, utilizing the groundwater quality data in 1982 and 2004, the aerial photos in 1982 and TM images in 2004, supported by the GIS, we probe into the law and the reason of its space-time change of the groundwater quality over the past 22 years in the paper. The results show： （1） There were obvious temporal and spatial changes of groundwater quality during the past 22 years. （2） Concentrations of NH4^＋, SO4^2- , NO3, NO2^-, Cl^- and the pH value, total hardness, total alkalinity increased significantly, in which NH4^2-, NO3, and NO2^- of groundwater exceeded the drinking water standards as a result of non-point pollution caused by the expansion of cultivated land and mass use of the fertilizer and pesticide. （3） Oppositely, Ca^2＋ and HCO3^- showed an obvious decline trend due to forest reduction and degradation and stony desertification. Meantime, there was a dynamic relation between the groundwater quality change and the land use change.

Impact of Land Use Changes on Surface Warming in China

Land use changes such as urbanization, agriculture, pasturing, deforestation, desertification and irrigation can change the land surface heat flux directly, and also change the atmospheric circulation indirectly, and therefore affect the local temperature. But it is difficult to separate their effects from climate trends such as greenhouse-gas effects. Comparing the decadal trends of the observation station data with those of the NCEP/NCAR Reanalysis (NNR) data provides a good method to separate the effects because the NNR is insensitive to land surface changes. The effects of urbanization and other land use changes over China are estimated by using the difference between the station and the NNR surface temperature trends. Our results show that urbanization and other land use changes may contribute to the observed 0.12℃ (10yr)-1 increase for daily mean surface temperature, and the0.20℃ (10yr)-1 and 0.03℃ (10 yr)-1 increases for the daily minimum and maximum surface temperatures, respectively. The urban heat island effect and the effects of other land-use changes may also play an important role in the diurnal temperature range change. The spatial pattern of the differences in trends shows a marked heterogeneity. The land surface degradation such as deforestation and desertification due to human activities over northern China, and rapidly-developed urbanization over southern China, may have mostly contributed to the increases at stations north of about 38°N and in Southeast China, respectively. Furthermore, the vegetation cover increase due to irrigation and fertilization may have contributed to the decreasing trend of surface temperature over the lower Yellow River Basin. The study illustrates the possible impacts of land use changes on surface temperature over China.

Land use change and its corresponding ecological responses:a review

This paper reviews the research on land use change and its corresponding ecological responses. Patterns of land use changes in spatio-temporal level are produced by the interaction of biophysical and socio-economic processes. Nowadays, the studies derived from different socioeconomic conditions and scales show that at short-term scale, human activities, rather than natural forces, have become a major force in shaping the environment, while biophysical factors control the trends and processes of land use change under the macro environmental background. Providing a scientific understanding of the process of land use change, the impacts of different land use decisions, and the ways that decisions are affected by a changing environment and increasing ecological variability are the priority areas for research： （1） explanation of scale dependency of drivers of land use change; （2） quantification of driving factors of land use change; （3） incorporation of biophysical feedbacks in land use change models： and （4） underlying processes and mechanisms of ecological impacts of land use change.

Land Use Changes in Northeast China Driven by Human Activities and Climatic Variation

Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland, marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the local climate. Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In terms of socio-economic driving forces, population augment, regional economic development, and national and provincial policies were confirmed as main driving factors for land use change.

Spatio-temporal Characteristics of Disturbance of Land Use Change on Major Ecosystem Function Zones in China

In recent years, because of increasing human activities, ecosystems have been substantially disturbed and their service functions have been greatly compromised. Based on the effect of land use changes on the major ecosystem services, we estimated the ecosystem comprehensive anthropogenic disturbance index(ECADI) and analyzed the spatio-temporal characteristics of changes in the ECADI in China from 1990 to 2010. The average ECADI of the major ecosystem function zones in China in 2010 is approximately 0.382. The ECADI of Northeast China and North China is slightly higher than that of Northwest China and Southwest China. Most zones have slight changes in the ECADI. The average increases of ECADI in the major ecosystem function zones in China from 1990 to 2000 and from 2000 to 2010 are 0.0024 and 0.0002, respectively. The increase is mainly due to reclamation and urbanization, whereas the decrease is due to the implementation of ecosystem protection policies. During the last 20 years, the ECADI of water resources conservation zones increased first, and then stopped. The ECADI of soil conservation zones increased first, and then declined. The ECADI of sandstorm prevention zones, biodiversity conservation zones and flooding mitigation zones increased continuously. Our results may provide proposals to the government regarding land use planning and ecosystem protection plans in the major ecosystem zones. The major ecosystem function zones in the western part of China have been protected effectively. However, the major ecosystem function zones in the eastern part of China require more protection in the future.